initial commit / add all books

83 files changed, 2188 insertions, 0 deletions

diff --git a/2921/CH1/EX1.2/Ex1_2.sce b/2921/CH1/EX1.2/Ex1_2.sce
new file mode 100755
index 000000000..c571fe7a9
--- /dev/null
+++ b/2921/CH1/EX1.2/Ex1_2.sce
@@ -0,0 +1,31 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-1.2   Page 13 ')    //Example 1.2
+
+Sy=61000                   //[psi] Tensile strength of AISI 1020 cold drawn steel from Appendix 4 Page no 470
+SF=2;                      //[] safety factor
+F=300;                     //[lb] Weight of the ball
+L=36;                      //[in] Length of round bar
+Sy=61000;                  //[psi] Tensile strength from Appendix 4
+M=F*L;                     //[in*lb] Bending moment Appendix 2
+
+Sall=Sy/SF;                //[psi] Allowable stress 
+Z=M/Sall;                  //[in^3] Section modulus for bending Sall=M/Z
+D=(32*Z/%pi)^(1/3);        //[in] Diameter of bar
+
+//Use 13/8 in bar
+D1=1.625;
+
+mprintf('\n\n Diameter of Bar is %f in',D1);
+
+//Checking Deflection
+I=%pi*D1^4/64;              //[in^4] Moment of inertia Appendix 3
+E=30*10^6;                  //[lb/in^2] Modulus of elasticity
+Delta=F*L^3/(3*E*I);        //[in] Deflection 
+
+//Note- In the book I=0.342 in^4 is used instead of I=0.3422814 in^4
+
+mprintf('\n The deflection of bar is %f in',Delta);
+
+
+//Note: The deviation of answer from the answer given in the book is due to round off error.(In the book values are rounded while in scilab actual values are taken)
diff --git a/2921/CH10/EX10.1/Ex10_1.sce b/2921/CH10/EX10.1/Ex10_1.sce
new file mode 100755
index 000000000..201aa19dc
--- /dev/null
+++ b/2921/CH10/EX10.1/Ex10_1.sce
@@ -0,0 +1,38 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-10.1 Page No.195\n');
+
+P=100;                //[lb/in^2] Hydraulic pressure
+F=450;                //[lb] Extension force
+Fr=400;               //[lb] Retraction force
+
+A=F/P;                //[in^2] Cross section area
+D=sqrt(4*A/%pi);      //[in] Bore of cylinder
+
+mprintf('\n The bore of cylinder is %f in.',D);
+
+//Use 2.5in bore cylinder
+
+Dm=2.5;               //[in] Bore of cylinder
+Dr=1;                 //[in] Diameter of rod
+A2=%pi*Dm^2/4-%pi*Dr^2/4; //[in^2]
+F2=P*A2;              //[lb] Force
+
+if F2>=Fr then
+    mprintf('\n The diameter of rod is %f in.',Dr);
+else 
+    mprintf('\n This would not meet requirement');
+end
+
+//This would meet requirement
+
+Ab=%pi*Dm^2/4;        //[in^2] Cross section area
+//Note-In the book V=180.7 is used instead of V=180.64158 
+d=20;                //[in] stroke
+V=Ab*d+A2*d;         //[in^3] Volume per cycle
+t=2;                 //[s] Cycle time
+FR=V/t;              //[in^3/s] Flowrate
+
+FR=FR*7.48*60/1728;  //[gal/min] Flowrate
+
+mprintf('\n Flow rate required is %f gal/min.',FR);
diff --git a/2921/CH10/EX10.2/Ex10_2.sce b/2921/CH10/EX10.2/Ex10_2.sce
new file mode 100755
index 000000000..ce24fa1dc
--- /dev/null
+++ b/2921/CH10/EX10.2/Ex10_2.sce
@@ -0,0 +1,35 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-10.2 Page No.198\n');
+
+Pa=100;              //[lb/in^2] Air pressure
+Da=4;                //[in] Diameter
+Aa=%pi*Da^2/4;       //[in^2] Cross section area
+
+F1=Pa*Aa;            //[lb] 
+Do=1;                //[in] 
+Ao=%pi*Do^2/4;       //[in] 
+Po=F1/Ao;            //[lb/in^2]
+
+mprintf('\n The oil pressure is %f lb/in^2.',Po);
+
+D2o=3;               //[in]
+A2o=%pi*D2o^2/4;     //[in^2]
+F2=Po*A2o;
+
+mprintf('\n Force F on piston rod is %f lb.',F2);
+
+D=1;                 //[in]
+d=4;                 //[in] 
+A=%pi*D^2/4;         //[in^2]
+
+V=A*d;               //[in^3]
+
+mprintf('\n The volume in 1-inch cylinder for the 4-inch travel is %f in^3.',V);
+
+A3=%pi*3^2/4;        //[in^2]
+l3=V/A3;             //[in]
+
+mprintf('\n Travel for 3-inch cylinder is %f in.',l3);
+
+
diff --git a/2921/CH11/EX11.1/Ex11_1.sce b/2921/CH11/EX11.1/Ex11_1.sce
new file mode 100755
index 000000000..6c745a8f1
--- /dev/null
+++ b/2921/CH11/EX11.1/Ex11_1.sce
@@ -0,0 +1,32 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-11.1 Page No.217\n');
+
+N2=60;
+N1=20;
+N3=20;
+N4=60;
+
+Vr=(N2/N1)*(N4/N3);
+
+//Output speed
+n1=3600;
+n4=n1/Vr;
+
+mprintf('\n The output speed is %f rpm.',n4);
+
+//Output torque
+T1=200;
+T4=T1*Vr;
+
+mprintf('\n The output torque is %f lb*in.',T4);
+
+//Input horsepower
+hpi=T1*n1/63000;
+
+mprintf('\n The input horsepower is %f hp.',hpi);
+
+//Output horsepower
+hpo=T4*n4/63000;
+
+mprintf('\n The output horsepower is %f hp.',hpo);
diff --git a/2921/CH11/EX11.2/Ex11_2.sce b/2921/CH11/EX11.2/Ex11_2.sce
new file mode 100755
index 000000000..77829670e
--- /dev/null
+++ b/2921/CH11/EX11.2/Ex11_2.sce
@@ -0,0 +1,35 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-11.2 Page No.219\n');
+
+Na=20;
+Nb=65;
+Nc=20;
+Nd=22;
+Ne=60;
+
+//train value
+Vr=(Nb/Na)*(Nd/Nc)*(Ne/Nd);
+
+mprintf('\n Train value = %f ',Vr);
+
+//Output speed
+na=3000;
+ne=na/Vr;
+
+mprintf('\n \Output speed = %f rpm.',ne);
+
+//Output torque
+Ta=10;
+Te=Ta*Vr;
+
+mprintf('\n Output torque = %f lb*in.',Te);
+
+//Direction
+
+mprintf('\n Direction\n   If Gear A is clockwise,\n   Gear B is counterclockwise.\n   Gear C is counterclockwise.\n   Gear D is clockwise. \n   Gear E is counterclockwise.');
+
+//Output power
+P=Te*ne;
+P=P*%pi/60;
+ mprintf('\n Output power = %f W.',P);
diff --git a/2921/CH11/EX11.3/Ex11_3.sce b/2921/CH11/EX11.3/Ex11_3.sce
new file mode 100755
index 000000000..f5d15d0a1
--- /dev/null
+++ b/2921/CH11/EX11.3/Ex11_3.sce
@@ -0,0 +1,26 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-11.3 Page No.231\n');
+
+Np=16;
+Ng=32;
+Pd=8;
+
+//Pitch diameter
+Dp=Np/Pd;
+
+mprintf('\n Pinion pitch diameter is %f in.',Dp);
+
+Dg=Ng/Pd;
+
+mprintf('\n Gear pitch diameter is %f in.',Dg);
+
+//Circular pitch
+Pc=%pi*Dp/Np;
+
+mprintf('\n Circular pitch is %f in.',Pc);
+
+//Centerline distance
+CC=(Dp+Dg)/2;
+
+mprintf('\n Centerline distance is %f in.',CC);
diff --git a/2921/CH11/EX11.4/Ex11_4.sce b/2921/CH11/EX11.4/Ex11_4.sce
new file mode 100755
index 000000000..74fc1bad5
--- /dev/null
+++ b/2921/CH11/EX11.4/Ex11_4.sce
@@ -0,0 +1,25 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-11.4 Page No.236\n');
+
+//Torque in input shaft
+hp=1.5;
+n=3450;
+T=63000*hp/n;
+
+mprintf('\n Torque in input shaft is %f lb*in.',T);
+
+//Note-In the book T=27.4 in-lb is used instead of T=27.391304
+
+//Output torque
+Ng=24;
+Np=10;
+Tout=(Ng/Np)*T;
+
+mprintf('\n Output torque is %f lb*in.',Tout);
+
+//Output speed
+nout=(Np/Ng)*n;
+
+mprintf('\n Output speed is %f rpm.',nout);
+
diff --git a/2921/CH11/EX11.5/Ex11_5.sce b/2921/CH11/EX11.5/Ex11_5.sce
new file mode 100755
index 000000000..a7d6df016
--- /dev/null
+++ b/2921/CH11/EX11.5/Ex11_5.sce
@@ -0,0 +1,37 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-11.5 Page No.241\n');
+
+//Gear train value
+Na=12;
+Nb=36;
+Nc=16;
+Nd=64;
+Vr=(Nb/Na)*(Nd/Nc);
+
+mprintf('\n Gear train value is %f ',Vr);
+
+//Motor torque
+hp=1.5;
+n=1750;
+T=63000*hp/n;
+
+mprintf('\n Motor torque is %f in-lb.',T);
+
+//Output torque
+Tout=T*Vr;
+
+mprintf('\n Output torque is %f in-lb.',Tout);
+
+//Output speed
+nout=n/Vr;
+
+mprintf('\n Output speed is %f rpm.',nout);
+
+//Directions
+mprintf('\n Directions\n  Gear A is clockwise.\n  Gear B is counterclockwise.\n  Gear C is counterclockwise.\n  Gear D is clockwise.');
+
+//Output power
+hp=T*n/63000;
+
+mprintf('\n Output power is %f hp.',hp);
diff --git a/2921/CH11/EX11.6/Ex11_6.sce b/2921/CH11/EX11.6/Ex11_6.sce
new file mode 100755
index 000000000..a6aeda841
--- /dev/null
+++ b/2921/CH11/EX11.6/Ex11_6.sce
@@ -0,0 +1,12 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-11.6 Page No.243\n');
+
+//Velocity ratio
+N2=2400;
+N1=20;
+Vr=N2/N1;
+
+mprintf('\n Velocity ratio = %f ',Vr);
+
+mprintf('\n Possible Solution: \n Three sets of gears \n   -20 tooth and 80 tooth\n   -20 tooth and 100 tooth\n   -20 tooth and 120 tooth.');
diff --git a/2921/CH12/EX12.1/Ex12_1.sce b/2921/CH12/EX12.1/Ex12_1.sce
new file mode 100755
index 000000000..b5269c579
--- /dev/null
+++ b/2921/CH12/EX12.1/Ex12_1.sce
@@ -0,0 +1,30 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-12.1 Page No.254\n');
+
+P=5;
+n=1725;
+T=63000*P/n;
+
+//Pitch circle diameter
+Np=20;
+Pd=8;
+Dp=Np/Pd;
+
+mprintf('\n Pitch circle diameter = %f in.',Dp);
+
+//Transmitted force
+Ft=2*T/Dp;
+
+mprintf('\n Transmitted force = %f lb.',Ft);
+
+//Separating force
+theta=20*%pi/180;
+Fn=Ft*tan(theta);
+
+mprintf('\n Separating force = %f lb.',Fn);
+
+//Maximum force
+Fr=Ft/cos(theta);
+
+mprintf('\n Maximum force = %f lb.',Fr);
diff --git a/2921/CH12/EX12.2/Ex12_2.sce b/2921/CH12/EX12.2/Ex12_2.sce
new file mode 100755
index 000000000..5ef68a3f6
--- /dev/null
+++ b/2921/CH12/EX12.2/Ex12_2.sce
@@ -0,0 +1,10 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-12.2 Page No.256\n');
+
+//Surface speed
+Dp=2.5;
+n=1725;
+Vm=%pi*Dp*n/12;
+
+mprintf('\n Surface speed = %f ft/min.',Vm);
diff --git a/2921/CH12/EX12.3/Ex12_3.sce b/2921/CH12/EX12.3/Ex12_3.sce
new file mode 100755
index 000000000..ad2d8bdf6
--- /dev/null
+++ b/2921/CH12/EX12.3/Ex12_3.sce
@@ -0,0 +1,20 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-12.3 Page No.258\n');
+//Pinion
+Su=95*10^3;
+Sn=0.5*Su;
+Y=0.320;
+b=1;
+Pd=8;
+
+Fsp=Sn*b*Y/Pd;
+
+mprintf('\n Force allowable for pinion = %f lb.',Fsp);
+
+//Gear
+Sn=0.5*88*10^3;
+Y=0.421;
+Fsg=Sn*b*Y/Pd;
+
+mprintf('\n Force allowable for gear = %f lb.',Fsg);
diff --git a/2921/CH12/EX12.4/Ex12_4.sce b/2921/CH12/EX12.4/Ex12_4.sce
new file mode 100755
index 000000000..6e4981960
--- /dev/null
+++ b/2921/CH12/EX12.4/Ex12_4.sce
@@ -0,0 +1,19 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-12.4 Page No.262\n');
+
+//Dynamic load
+Vm=1129;
+Ft=146;
+Fd=(600+Vm)*Ft/600;
+
+mprintf('\n Dynamic load = %f lb.',Fd);
+
+Fs=1900;
+Nsf=2;
+
+//Comparing to the allowable stress
+
+if (Fs/Nsf)>Fd then
+    mprintf('\n This is an acceptable design.');
+end
diff --git a/2921/CH12/EX12.5/Ex12_5.sce b/2921/CH12/EX12.5/Ex12_5.sce
new file mode 100755
index 000000000..33e7126b5
--- /dev/null
+++ b/2921/CH12/EX12.5/Ex12_5.sce
@@ -0,0 +1,41 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-12.5 Page No.263\n');
+
+Su=55*10^3;
+Sn=0.5*Su;
+
+Np=24;
+Pd=12;
+Dp=Np/Pd;
+
+mprintf('\n Pitch circle diameter = %f in.',Dp);
+
+n=1800;
+Vm=%pi*Dp*n/12;
+
+mprintf('\n Surface speed = %f ft/min.',Vm);
+
+b=3/4;
+Y=0.302;
+Fs=Sn*b*Y/Pd;
+
+mprintf('\n Allowable stress = %f lb.',Fs);
+
+Fd=Fs;
+Ft=600*Fd/(600+Vm);
+
+mprintf('\n Force transmitted = %f lb.',Ft);
+
+T=Ft*Dp/2;
+
+P=T*n/63000;
+
+mprintf('\n Power transmitted = %f hp.',P);
+
+//Compared to catalog
+hp_catalog=4.14;
+
+Nsf=P/hp_catalog;
+
+mprintf('\n Safety factor = %f .',Nsf);
diff --git a/2921/CH12/EX12.6/Ex12_6.sce b/2921/CH12/EX12.6/Ex12_6.sce
new file mode 100755
index 000000000..7522f0026
--- /dev/null
+++ b/2921/CH12/EX12.6/Ex12_6.sce
@@ -0,0 +1,41 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-12.6 Page No.266\n');
+
+//Miscellaneous properties
+Np=48;
+Pd=12;
+Dp=Np/Pd;
+Vr=3;
+Ng=Np*Vr;
+
+//Surface speed
+n=900;
+Vm=%pi*Dp*n/12;
+
+mprintf('\n Surface speed = %f ft/min.',Vm);
+
+//Force on teeth
+hp=2;
+Ft=33000*hp/Vm;
+
+mprintf('\n Force on teeth = %f lb.',Ft);
+
+//Dynamic force
+Fd=(600+Vm)*Ft/600;
+
+mprintf('\n Dynamic force = %f lb.',Fd);
+
+//Width
+Su=30*10^3;
+Sn=0.4*Su;
+Y=0.344;
+Nsf=2;
+b=Fd*Nsf*Pd/(Sn*Y);
+b=round(b);
+
+mprintf('\n Width = %f in.',b);
+
+if (8/Pd)<b&b<(12.5/Pd) then
+    mprintf('\n This is an acceptable design.');
+end
diff --git a/2921/CH12/EX12.7/Ex12_7.sce b/2921/CH12/EX12.7/Ex12_7.sce
new file mode 100755
index 000000000..984811df9
--- /dev/null
+++ b/2921/CH12/EX12.7/Ex12_7.sce
@@ -0,0 +1,42 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-12.7 Page No.270\n');
+
+Su=95*10^3;
+Sn=0.5*Su;
+Np=24;
+Pd=16;
+Dp=Np/Pd;
+
+//Torque
+n=3450;
+P=3;
+T=P*63000/n;
+
+mprintf('\n Torque = %f in-lb.',T);
+
+//Force transmitted
+Ft=2*T/Dp;
+
+mprintf('\n Force transmitted = %f lb.',Ft);
+
+//Surface speed
+Vm=%pi*Dp*n/12;
+
+mprintf('\n Surface speed = %f ft/min.',Vm);
+
+//Force allowable
+Y=0.337;
+b=1;
+Fs=Sn*b*Y/Pd;
+
+mprintf('\n Force allowable = %f lb.',Fs);
+
+//Dynamic load using Buckingham's equation
+C=830;
+Fd=Ft+0.05*Vm*(b*C+Ft)/(0.05*Vm+(b*C+Ft)^0.5);
+
+Nsf=1.4;
+if (Fs/Nsf)>Fd then
+    mprintf('\n This is a suitable design');
+end
diff --git a/2921/CH12/EX12.8/Ex12_8.sce b/2921/CH12/EX12.8/Ex12_8.sce
new file mode 100755
index 000000000..e16e376d5
--- /dev/null
+++ b/2921/CH12/EX12.8/Ex12_8.sce
@@ -0,0 +1,29 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-12.8 Page No.272\n');
+
+Ng=42;
+Np=24;
+Q=2*Ng/(Ng+Np);
+
+Kg=270;
+Dp=1.5;
+b=1;
+
+Fw=Dp*b*Q*Kg;
+Fd=699;
+Nsf=1.2;
+
+if (Fw/Nsf)<Fd then
+    mprintf('\n (Fw/Nsf)<Fd So this would not be suitable design');
+end
+
+//If the surfaces each had a BHN = 450
+
+Kg=470;
+Fw=Dp*b*Q*Kg;
+
+if(Fw/Nsf)>Fd then
+    mprintf('\n\n If the surfaces each had a BHN = 450');
+    mprintf('\n (Fw/Nsf)>Fd So this would be suitable design.');
+end
diff --git a/2921/CH13/EX13.1/Ex13_1.sce b/2921/CH13/EX13.1/Ex13_1.sce
new file mode 100755
index 000000000..5ff997cdd
--- /dev/null
+++ b/2921/CH13/EX13.1/Ex13_1.sce
@@ -0,0 +1,31 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-13.1 Page No.280\n');
+
+//Pitch-line velocity
+Nt=24;
+Pd=12;
+Dp=Nt/Pd;
+n=1750;
+Vm=%pi*Dp*n/12;
+
+mprintf('\n Pitch-line velocity = %f ft/min.',Vm);
+
+//Transmitted force
+hp=5;
+Ft=33000*hp/Vm;
+
+mprintf('\n Transmitted force = %f lb.',Ft);
+
+//Axial force
+psi=15*%pi/180;
+Fa=Ft*tan(psi);
+
+mprintf('\n Axial force = %f lb.',Fa);
+
+//Separating force
+theta=20*%pi/180;
+psit=atan(tan(theta)/cos(psi));
+Fn=Ft*tan(psit);
+
+mprintf('\n Separating force = %f lb.',Fn);
diff --git a/2921/CH13/EX13.2/Ex13_2.sce b/2921/CH13/EX13.2/Ex13_2.sce
new file mode 100755
index 000000000..6beca29b7
--- /dev/null
+++ b/2921/CH13/EX13.2/Ex13_2.sce
@@ -0,0 +1,35 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-13.2 Page No.282\n');
+
+//Normal plane pitch
+Pd=16;
+psi=45*%pi/180;
+Pdn=Pd/cos(psi);
+
+mprintf('\n Normal plane pitch = %f in.',Pdn);
+
+N=24;
+S=30000;
+b=0.5;
+Ne=N/cos(psi)^3;
+Y=0.427;
+Fs=S*b*Y/Pdn;
+
+mprintf('\n Allowable force = %f lb.',Fs);
+
+Dp=24/16;
+n=600;
+Vm=%pi*Dp*n/12;
+
+mprintf('\n Surface speed = %f ft/min.',Vm);
+
+Ft=Fs/((600+Vm)/600);
+
+mprintf('\n Force transmitted = %f lb.',Ft);
+
+P=Ft*Vm/33000;
+
+mprintf('\n Power rating = %f hp.',P);
+
+//Note-There is an error in the answer given in textbook
diff --git a/2921/CH13/EX13.3/Ex13_3.sce b/2921/CH13/EX13.3/Ex13_3.sce
new file mode 100755
index 000000000..9f5096f42
--- /dev/null
+++ b/2921/CH13/EX13.3/Ex13_3.sce
@@ -0,0 +1,44 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-13.3 Page No.286\n');
+
+Np=24;
+Ng=36;
+Pd=8;
+Yp=33.7*%pi/180;
+Yg=56.3*%pi/180;
+theta=14.5*%pi/180;
+
+//Pitch diameter
+Dp=Np/Pd;
+
+mprintf('\n Pitch diameter = %f in.',Dp);
+
+//Transmitted force
+n=2200;
+P=8;
+T=63000*P/n;
+
+Ft=2*T/Dp;
+
+mprintf('\n Transmitted force = %f lb.',Ft);
+
+//Separating force - Pinion
+Fnp=Ft*tan(theta)*cos(Yp);
+
+mprintf('\n Separating force-Pinion = %f lb.',Fnp);
+
+//Separating force-Gear
+Fng=Ft*tan(theta)*cos(Yg);
+
+mprintf('\n Separating force = %f lb.',Fng);
+
+//Axial force-Pinion
+Fap=Ft*tan(theta)*sin(Yp);
+
+mprintf('\n Axial force-Pinion= %f lb.',Fap);
+
+//Axial force-Gear
+Fag=Ft*tan(theta)*sin(Yg);
+
+mprintf('\n Axial force-Gear = %f lb.',Fag);
diff --git a/2921/CH13/EX13.4/Ex13_4.sce b/2921/CH13/EX13.4/Ex13_4.sce
new file mode 100755
index 000000000..d34c6ac06
--- /dev/null
+++ b/2921/CH13/EX13.4/Ex13_4.sce
@@ -0,0 +1,42 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-13.4 Page No.288\n');
+
+//Pitch diameter
+Ng=60;
+Pd=6;
+Dp=Ng/Pd;
+
+mprintf('\n Pitch diameter = %f in.',Dp);
+
+//Circular pitch
+Pc=%pi*Dp/Ng;
+
+mprintf('\n Circular pitch = %f in.',Pc);
+
+L=Pc;
+
+//Lead angle
+D=2;
+LA=atan(L/(%pi*D));
+LA=LA*180/%pi;
+
+mprintf('\n Lead angle = %f deg.',LA);
+
+//Centerline distance
+CC=(D+Dp)/2;
+
+mprintf('\n Centerline distance = %f in.',CC);
+
+//Velocity ratio
+Ntgear=60;
+Nstarts_worm=1;
+Vr=Ntgear/Nstarts_worm;
+
+mprintf('\n Velocity ratio = %f',Vr);
+
+//Output speed
+nin=1750;
+nout=nin/Vr;
+
+mprintf('\n Output speed = %f rpm.',nout);
diff --git a/2921/CH13/EX13.5/Ex13_5.sce b/2921/CH13/EX13.5/Ex13_5.sce
new file mode 100755
index 000000000..4d5f6d9fa
--- /dev/null
+++ b/2921/CH13/EX13.5/Ex13_5.sce
@@ -0,0 +1,42 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-13.5 Page No.292\n');
+
+//Normal circular pitch
+Pc=0.524;
+LA=4.77*%pi/180;
+Pcn=Pc*cos(LA);
+
+mprintf('\n Normal circular pitch = %f in.',Pcn);
+
+//Force transmitted
+hp=5;
+n=29.2;
+T=63000*hp/n;
+Dp=10;
+Ft=2*T/Dp;
+
+mprintf('\n Force transmitted = %f lb.',Ft);
+
+Vm=%pi*Dp*n/12;
+
+//Dynamic load
+Fd=(1200+Vm)*Ft/1200;
+
+mprintf('\n Dynamic load = %f lb.',Fd);
+
+//Force allowable
+Su=95*10^3;
+Y=0.392;
+b=1;
+Sn=0.5*Su;
+Fs=Sn*Y*b*Pcn/%pi;
+
+mprintf('\n Force allowable = %f lb.',Fs);
+
+//Safty factor
+Nsf=Fs/Fd;
+
+mprintf('\n Safty factor = %f .',Nsf);
+
+//Note-There is an error in the answer given in textbook
diff --git a/2921/CH13/EX13.6/Ex13_6.sce b/2921/CH13/EX13.6/Ex13_6.sce
new file mode 100755
index 000000000..7d1876b1a
--- /dev/null
+++ b/2921/CH13/EX13.6/Ex13_6.sce
@@ -0,0 +1,22 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-13.6 Page No.294\n');
+
+//Efficiency
+LA=4.77*%pi/180;
+f=0.03;
+e=tan(LA)*(1-f*tan(LA))/(f+tan(LA));
+
+mprintf('\n Efficiency = %f .',e);
+
+//Torque input
+hp=5;
+n=1750;
+T=63000*hp/n;
+
+mprintf('\n Torque input = %f in-lb.',T);
+
+Vr=60;
+Tout=0.73*Vr*T;
+
+mprintf('\n Output torque = %f in-lb.',Tout);
diff --git a/2921/CH13/EX13.7/Ex13_7.sce b/2921/CH13/EX13.7/Ex13_7.sce
new file mode 100755
index 000000000..beb0e3326
--- /dev/null
+++ b/2921/CH13/EX13.7/Ex13_7.sce
@@ -0,0 +1,11 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-13.7 Page No.296\n');
+
+hpin=5
+e=0.73;
+Q=(1-e)*hpin*2544;
+
+mprintf('\n Heat generated by system = %f Btu/hr.',Q);
+
+//Note-There is an error in the answer given in textbook
diff --git a/2921/CH14/EX14.1/Ex14_1.sce b/2921/CH14/EX14.1/Ex14_1.sce
new file mode 100755
index 000000000..25851493f
--- /dev/null
+++ b/2921/CH14/EX14.1/Ex14_1.sce
@@ -0,0 +1,42 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-14.1 Page No.306\n');
+
+//Torque on small pulley
+hp=2;
+n=2450;
+T=63000*hp/n;
+
+mprintf('\n Torque on small pulley = %f in-lb.',T);
+r=6/2;
+Fd=T/r;
+
+//Front force
+Fb=10;
+Ff=Fd+Fb;
+
+mprintf('\n Front force = %f lb.',Ff);
+
+//Force pulling the shafts
+Ft=Ff+Fb
+
+mprintf('\n Force pulling the shafts = %f lb.',Ft);
+
+//Surface speed
+D=2*r;
+Vm=%pi*D*n/12;
+
+mprintf('\n Surface speed = %f ft/min.',Vm);
+
+//Ratio
+D2=10;
+Mw=D2/D;
+
+mprintf('\n Ratio = %f .',Mw);
+
+//Output speed
+no=n/Mw;
+
+mprintf('\n Output speed = %f rpm.',no);
+
+//Note-There is an error in the answer given in textbook
diff --git a/2921/CH14/EX14.2/Ex14_2.sce b/2921/CH14/EX14.2/Ex14_2.sce
new file mode 100755
index 000000000..465ddf592
--- /dev/null
+++ b/2921/CH14/EX14.2/Ex14_2.sce
@@ -0,0 +1,39 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-14.2 Page No.310\n');
+
+//Length of belt
+C=19;
+D1=4;
+D2=6;
+
+L1=2*C+1.57*(D1+D2)+(D2-D1)^2/(4*C);
+
+//Assuming a 54-inch belt is available
+L=54;
+
+mprintf('\n Length of belt = %f in.',L);
+
+//Centerline distance
+B=4*L-6.28*(D2+D1);
+
+C=(B+sqrt(B^2-32*(D2-D1)^2))/16;
+
+mprintf('\n Centerline distance = %f in.',C);
+
+//Ratio
+Mw=D2/D1;
+
+mprintf('\n Ratio = %f.',Mw);
+
+//Surface speed
+n=1800;
+Vm=%pi*D1*n/12;
+
+mprintf('\n Surface speed = %f ft/min.',Vm);
+
+//Angle of contact
+
+theta=180-2*(180/%pi)*asin((D2-D1)/(2*C));
+
+mprintf('\n Angle of contact = %f deg.',theta);
diff --git a/2921/CH14/EX14.3/Ex14_3.sce b/2921/CH14/EX14.3/Ex14_3.sce
new file mode 100755
index 000000000..c4921112e
--- /dev/null
+++ b/2921/CH14/EX14.3/Ex14_3.sce
@@ -0,0 +1,22 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-14.3 Page No.315\n');
+
+//Power rating of belt
+P1=27+2.98;
+SF=1.5;
+P=P1/SF;
+P=round(P);
+
+mprintf('\n Power rating = %f hp.',P);
+
+//Length of belt
+C=20;
+D1=8;
+D2=16;
+L1=2*C+1.57*(D1+D2)+(D2-D1)^2/(4*C);
+
+//Use an 80-inch belt
+L=80;
+
+mprintf('\n Length of belt = %f in.',L);
diff --git a/2921/CH14/EX14.4/Ex14_4.sce b/2921/CH14/EX14.4/Ex14_4.sce
new file mode 100755
index 000000000..6522ab95d
--- /dev/null
+++ b/2921/CH14/EX14.4/Ex14_4.sce
@@ -0,0 +1,48 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-14.4 Page No.321\n');
+
+P=5.31;
+
+mprintf('\n Horsepower rating = %f hp.',P);
+
+Nti=12;
+N1=1800;
+N2=900;
+
+//Output sprocket
+Nto=(N1/N2)*Nti;
+
+mprintf('\n Number of tooth on output sprocket = %f.',Nto);
+
+//Surface speed
+Pc=0.5;
+D1=Pc*Nti/%pi;
+n=1800;
+Vm=%pi*D1*n/12;
+
+mprintf('\n Surface speed = %f ft/min.',Vm);
+
+mprintf('\n Type of lubrication - Bath or disc lubrication');
+
+//Length of chain
+C=10;
+D2=Pc*Nto/%pi;
+
+L1=2*C+1.57*(D1+D2)+(D2-D1)^2/(4*C);
+
+//Use 29 or 30 inch chain
+
+L=30;
+
+mprintf('\n Length of chain = %f in.', L);
+
+hp=5.31;
+
+T=63000*hp/n;
+
+F=2*T/D1;
+
+mprintf('\n Force in chain = %f lb.',F);
+
+//Comparism with ultimate strength 3700 lb - not a valid comparison because of speed etc.
diff --git a/2921/CH15/EX15.1/Ex15_1.sce b/2921/CH15/EX15.1/Ex15_1.sce
new file mode 100755
index 000000000..13a06ceb0
--- /dev/null
+++ b/2921/CH15/EX15.1/Ex15_1.sce
@@ -0,0 +1,31 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-15.1 Page No.332\n');
+
+//Torque
+P=5;
+n=1750;
+T=63000*P/n;
+
+mprintf('\n Torque = %f in-lb.',T);
+
+//Length of key for shear
+Su=61000;
+Ss=0.5*Su;
+b=0.125;
+D=0.5;
+Ls1=2*T/(Ss*b*D);
+SF=2.5;
+
+Ls=SF*Ls1;
+
+mprintf('\n Length of key for shear = %f in.',Ls);
+
+//Length of key for compression
+Sc=51000;
+t=0.125;
+Lc1=4*T/(Sc*t*D);
+
+Lc=SF*Lc1;
+
+mprintf('\n Length of key for compression = %f in.',Lc);
diff --git a/2921/CH15/EX15.2/Ex15_2.sce b/2921/CH15/EX15.2/Ex15_2.sce
new file mode 100755
index 000000000..bf2070c96
--- /dev/null
+++ b/2921/CH15/EX15.2/Ex15_2.sce
@@ -0,0 +1,25 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-15.2 Page No.335\n');
+
+//Torque capacity
+Ss=30500;
+D=1;
+L=2;
+T1=Ss*%pi*D^2*L/16;
+
+SF=2;
+
+T=T1/SF;
+
+mprintf('\n Torque capacity 1 = %f in-lb.',T);
+n=6;
+d=0.81;
+A=(D-d)*L*n/2;
+
+S=1000;
+rm=(1+0.810)/4;
+
+T2=S*A*rm;
+
+mprintf('\n Torque capacity 2 = %f in-lb.',T2);
diff --git a/2921/CH16/EX16.1/Ex16_1.sce b/2921/CH16/EX16.1/Ex16_1.sce
new file mode 100755
index 000000000..d85c16d06
--- /dev/null
+++ b/2921/CH16/EX16.1/Ex16_1.sce
@@ -0,0 +1,18 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-16.1 Page No.358\n');
+
+//Torque capacity
+f=0.3;
+N=120;
+ro=12;
+ri=9;
+Tf=f*N*(ro+ri)/2;
+
+mprintf('\n Torque capacity = %f in-lb.',Tf);
+n=2000;
+//Power
+
+Pf=Tf*n/63000;
+
+mprintf('\n Power = %f hp.',Pf);
diff --git a/2921/CH16/EX16.2/Ex16_2.sce b/2921/CH16/EX16.2/Ex16_2.sce
new file mode 100755
index 000000000..d694e5192
--- /dev/null
+++ b/2921/CH16/EX16.2/Ex16_2.sce
@@ -0,0 +1,18 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-16.2 Page No.359\n');
+
+//Normal force
+W=100;
+L=20;
+a=4;
+N=(W*L)/a;
+
+mprintf('\n Normal force = %f lb.',N);
+
+//Torque friction
+f=0.4;
+D=12;
+Tf=f*N*D/2;
+
+mprintf('\n Torque friction = %f in-lb.',Tf);
diff --git a/2921/CH16/EX16.3/Ex16_3.sce b/2921/CH16/EX16.3/Ex16_3.sce
new file mode 100755
index 000000000..735ae09f2
--- /dev/null
+++ b/2921/CH16/EX16.3/Ex16_3.sce
@@ -0,0 +1,18 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-16.3 Page No.360\n');
+
+//For alpha=20 deg.
+alpha=20*(%pi/180);
+f=0.35;
+rm=12/2;
+Fa=75;
+Tf=(f*rm*Fa)/(sin(alpha)+f*cos(alpha));
+
+mprintf('\n Torque capacity (alpha=20 deg.) = %f in-lb.',Tf);
+
+//For alpha=10 deg.
+alpha=10*(%pi/180);
+Tf=(f*rm*Fa)/(sin(alpha)+f*cos(alpha));
+
+mprintf('\n Torque capacity (alpha=10 deg.) = %f in-lb.',Tf);
diff --git a/2921/CH16/EX16.4/Ex16_4.sce b/2921/CH16/EX16.4/Ex16_4.sce
new file mode 100755
index 000000000..969f6e581
--- /dev/null
+++ b/2921/CH16/EX16.4/Ex16_4.sce
@@ -0,0 +1,35 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-16.4 Page No.361\n');
+
+//Stopping rate
+V=60*5280/3600;
+Va=0.5*V;
+D=400;
+t=D/Va;
+a=V/t;
+
+mprintf('\n Stopping rate = %f ft/sec^2.',a);
+
+//Stopping force
+W=40000;
+g=32.2;
+F=W*a/g;
+
+//Torque
+r=36/2;
+T=F*r;
+
+mprintf('\n Torque = %f in-lb.',T);
+
+//For each wheel
+T=T/10;
+
+//Braking normal force
+rm=10;
+f=0.4;
+N=T/(f*rm);
+
+mprintf('\n Braking normal force = %f lb.',N);
+
+//Note-There is an error in the answer given in textbook
diff --git a/2921/CH16/EX16.5/Ex16_5.sce b/2921/CH16/EX16.5/Ex16_5.sce
new file mode 100755
index 000000000..b00b8e7ea
--- /dev/null
+++ b/2921/CH16/EX16.5/Ex16_5.sce
@@ -0,0 +1,33 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-16.5 Page No.365\n');
+W=3500;
+V=73;
+g=32.2;
+V=50*5280/3600;
+V=round(V);
+
+//Kinetic energy to be absorbed
+KE=W*V^2/(2*g);
+
+mprintf('\n Kinetic energy to be absorbed = %f ft-lb.',KE);
+
+//Temperature rise
+Uf=KE;
+Wb=40;
+c=93;
+deltaT=Uf/(Wb*c);
+
+mprintf('\n Temperature rise = %f deg.',deltaT);
+
+//Stopping time
+a=20;
+t=V/a;
+
+mprintf('\n Stopping time = %f sec.',t);
+
+//Frictional power
+t=round(t*10)/10;
+fhp=Uf/(550*t);
+
+mprintf('\n Frictional power = %f hp.',fhp)
diff --git a/2921/CH17/EX17.1/Ex17_1.sce b/2921/CH17/EX17.1/Ex17_1.sce
new file mode 100755
index 000000000..b0e5f2a18
--- /dev/null
+++ b/2921/CH17/EX17.1/Ex17_1.sce
@@ -0,0 +1,47 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-17.1 Page No.379\n');
+
+hp=5;
+n=1750;
+T=63000*hp/n;
+
+//Torsional stress in the shaft
+D=0.75;
+Z1=%pi*D^3/16;
+
+Ss=T/Z1;
+
+mprintf('\n Torsional stress in the shaft = %f lb/in^2.',Ss);
+
+//Load at the gear pitch circle
+Nt=40;
+Pd=10;
+Dp=Nt/Pd;
+
+Ft=2*T/Dp;
+
+mprintf('\n Load at gear pitch circle = %f lb.',Ft);
+
+//Resultant force on the shaft
+theta=20*%pi/180;
+Fr=Ft/cos(theta);
+
+mprintf('\n Resultant force = %f lb.',Fr);
+
+//Maximum moment
+L=15;
+Mm=Fr*L/4;
+
+mprintf('\n Maximum moment = %f in-lb.',Mm);
+
+//Stress
+D2=0.75;
+Z2=%pi*D2^3/32;
+Z2=round(Z2*1000)*10^-3;
+
+S=Mm/Z2;
+
+mprintf('\n Stress = %f lb/in^2.',S);
+
+//Note-There is an error in the answer given in textbook
diff --git a/2921/CH17/EX17.2/Ex17_2.sce b/2921/CH17/EX17.2/Ex17_2.sce
new file mode 100755
index 000000000..a9bcdffb9
--- /dev/null
+++ b/2921/CH17/EX17.2/Ex17_2.sce
@@ -0,0 +1,11 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-17.2 Page No.383\n');
+
+//Combined stress using the maximum shear stress theorem
+
+Ss=2170;
+S=8780;
+Sr=sqrt(Ss^2+(S/2)^2);
+
+mprintf('\n Combined stress = %f lb/in^2.',Sr);
diff --git a/2921/CH17/EX17.3/Ex17_3.sce b/2921/CH17/EX17.3/Ex17_3.sce
new file mode 100755
index 000000000..d73d83e6d
--- /dev/null
+++ b/2921/CH17/EX17.3/Ex17_3.sce
@@ -0,0 +1,12 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-17.3 Page No.383\n');
+
+//Combined stress using the maximum normal stress theory
+Ss=2170;
+S=8780;
+Sr=S/2+sqrt(Ss^2+(S/2)^2);
+
+mprintf('\n Combined stress = %f lb/in^2.',Sr);
+
+//Note-There is an error in the answer given in textbook
diff --git a/2921/CH17/EX17.4/Ex17_4.sce b/2921/CH17/EX17.4/Ex17_4.sce
new file mode 100755
index 000000000..ba28e5e9f
--- /dev/null
+++ b/2921/CH17/EX17.4/Ex17_4.sce
@@ -0,0 +1,21 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-17.4 Page No.385\n');
+
+//Modifying factors for Sn
+Su=88000;
+Csize=0.85;
+Csurface=0.88;
+Ctype=1;
+
+Sn=Csize*Csurface*Ctype*(0.5*Su);
+Kt=2.3;
+S=9300;
+
+N=Sn/(Kt*S);
+
+if N>2 then
+    mprintf('\n It would be an acceptable design.');
+else
+    mprintf('\n N<2,So this is not a suitable design for long term use.');
+end
diff --git a/2921/CH17/EX17.5/Ex17_5.sce b/2921/CH17/EX17.5/Ex17_5.sce
new file mode 100755
index 000000000..36f6e790c
--- /dev/null
+++ b/2921/CH17/EX17.5/Ex17_5.sce
@@ -0,0 +1,16 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-17.5 Page No.388\n');
+
+//Deflection
+D=0.75;
+E=30*10^6;
+L=15;
+F=96;
+I=%pi*D^4/64;
+
+delta=F*L^4/(48*E*I);
+delta=floor(100*delta)*10^-2;
+Nc=188/sqrt(delta);
+
+mprintf('\n Critical speed = %f rpm.',Nc);
diff --git a/2921/CH18/EX18.1/Ex18_1.sce b/2921/CH18/EX18.1/Ex18_1.sce
new file mode 100755
index 000000000..a08dd93d6
--- /dev/null
+++ b/2921/CH18/EX18.1/Ex18_1.sce
@@ -0,0 +1,13 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-18.1 Page No.399\n');
+
+//Torque
+Dp=(1.5+1.208)/2;
+F=5800;
+L=1/3;
+f=0.15;
+
+Tup=(F*Dp/4)*(L+%pi*f*Dp)/(%pi*Dp-f*L);
+
+mprintf('\n Torque up = %f in-lb.',Tup);
diff --git a/2921/CH18/EX18.2/Ex18_2.sce b/2921/CH18/EX18.2/Ex18_2.sce
new file mode 100755
index 000000000..52ce63d4d
--- /dev/null
+++ b/2921/CH18/EX18.2/Ex18_2.sce
@@ -0,0 +1,28 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-18.2 Page No.400\n');
+
+//Lead angle
+L=1/3;
+Dp=1.354;
+LA=atan(L/(%pi*Dp));
+
+mprintf('\n Lead angle = %f deg.',LA*180/%pi);
+
+//Efficiency
+f=0.15;
+e=tan(LA)*(1-f*tan(LA))/(tan(LA)+f);
+
+mprintf('\n Efficiency = %f',e*100);
+
+//Power
+n=175;
+T=454;
+P=T*n/63000;
+Pt=P*2;
+
+mprintf('\n Power = %f hp per lead screw.',P);
+
+if f>tan(LA) then
+    mprintf('\n It is self-locking');
+end
diff --git a/2921/CH18/EX18.3/Ex18_3.sce b/2921/CH18/EX18.3/Ex18_3.sce
new file mode 100755
index 000000000..58c71d643
--- /dev/null
+++ b/2921/CH18/EX18.3/Ex18_3.sce
@@ -0,0 +1,23 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-18.3 Page No.402\n');
+L=1/4;
+
+Dp=1.375;
+LA=atan(L/(%pi*Dp));
+
+mprintf('\n Lead angle = %f deg.',LA*180/%pi);
+
+//Torque
+phi=14.5*%pi/180;
+f=0.15;
+F=5800;
+Tup=(F*Dp/4)*(cos(phi)*tan(LA)+f)/(cos(phi)-f*tan(LA));
+
+mprintf('\n Torque = %f in-lb.',Tup);
+
+//Power
+n=175*4/3;
+P=Tup*n/63000;
+
+mprintf('\n Power = %f hp per lead screw.',P)
diff --git a/2921/CH18/EX18.4/Ex18_4.sce b/2921/CH18/EX18.4/Ex18_4.sce
new file mode 100755
index 000000000..df93a3c52
--- /dev/null
+++ b/2921/CH18/EX18.4/Ex18_4.sce
@@ -0,0 +1,16 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-18.4 Page No.405\n');
+
+//Torque
+L=0.5;
+F=5800/2;
+T=0.177*F*L;
+
+mprintf('\n Torque = %f in-lb.',T);
+
+//Power
+n=175*2/3;
+P=T*n/63000;
+
+mprintf('\n Power = %f hp.',P);
diff --git a/2921/CH19/EX19.1/Ex19_1.sce b/2921/CH19/EX19.1/Ex19_1.sce
new file mode 100755
index 000000000..fa76375cb
--- /dev/null
+++ b/2921/CH19/EX19.1/Ex19_1.sce
@@ -0,0 +1,27 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-19.1 Page No.417\n');
+
+//Length
+F=20;
+n=500;
+PV=3000;
+L1=%pi*F*n/(12*PV);
+
+//Use 7/8-inch or longer bearing
+
+L=7/8;
+
+mprintf('\n Length of bearing = %f in.',L);
+
+//Maximum pressure
+A=(3/4)*(7/8);
+P=F/A;
+
+mprintf('\n Maximum pressure = %f lb/in^2.',P);
+
+//Maximum velocity
+D=3/4;
+V=%pi*D*n/12;
+
+mprintf('\n Maximum velocity = %f ft/min.',V);
diff --git a/2921/CH19/EX19.2/Ex19_2.sce b/2921/CH19/EX19.2/Ex19_2.sce
new file mode 100755
index 000000000..f58351e33
--- /dev/null
+++ b/2921/CH19/EX19.2/Ex19_2.sce
@@ -0,0 +1,14 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-19.2 Page No.421\n');
+
+//Life in hours of operation
+t=0.01;
+K=12*10^-10;
+P=30.5;
+V=98;
+T=t/(K*P*V);
+
+mprintf('\n Life = %f hours.',T);
+
+//Note-There is an error in the answer given in textbook
diff --git a/2921/CH2/EX2.1/Ex2_1.sce b/2921/CH2/EX2.1/Ex2_1.sce
new file mode 100755
index 000000000..bb6e0baf6
--- /dev/null
+++ b/2921/CH2/EX2.1/Ex2_1.sce
@@ -0,0 +1,9 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-2.1   Page 26 ')    //Example 2.1
+
+T=1080*12;                  //[in*lb] Torque in axle
+d=30;                       //[in] Diameter of tire
+F=T/(d/2);                  //[lb] Force exerted on the road surface
+
+mprintf('\n\n The tire exerts %f lb force on the road surface',F);
diff --git a/2921/CH2/EX2.2/Ex2_2.sce b/2921/CH2/EX2.2/Ex2_2.sce
new file mode 100755
index 000000000..395c3bc56
--- /dev/null
+++ b/2921/CH2/EX2.2/Ex2_2.sce
@@ -0,0 +1,28 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-2.2   Page 28 ')    //Example 2.2
+
+G=3.6;                           //Diffential ratio
+N=3500/G;                        //[rpm] Axle rotational speed
+d=30;                            //[in] Diameter of tire
+dist=N/(60)*(%pi*d)              //[in] Distance traveled in 1 sec
+dist=dist/12;                    //[ft] Distance traveled in 1 sec
+t=1;                             //[sec] Time period
+F=864;                           //[lb] Force exerted by tire on road surface
+
+W=F*dist;                        //[ft*lb] Workdone in 1 sec
+P=F*dist/t;                      //[ft*lb/sec] Power
+hp=P/550;                        //[hp] Power in horse power 1hp=550 ft*lb/sec
+
+mprintf('\n\n Power to do work %f hp',hp);
+
+//Comparing it to motor output:
+
+Tm=300*12;                        //[in*lb] Engine torque
+Nm=3500;                          //[rpm] Engine speed
+Pm=Tm*Nm/63000; 
+
+mprintf('\n Motor output %f hp',Pm);
+mprintf('\n The power output equaled the power at tire/road surface.');
+
+//Note: The deviation of answer from the answer given in the book is due to round off error.(In the book values are rounded while in scilab actual values are taken)
diff --git a/2921/CH2/EX2.3/Ex2_3.sce b/2921/CH2/EX2.3/Ex2_3.sce
new file mode 100755
index 000000000..9fd946f0a
--- /dev/null
+++ b/2921/CH2/EX2.3/Ex2_3.sce
@@ -0,0 +1,13 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-2.3   Page 29 ')    //Example 2.3
+
+T=300*12;               //[in*lb] Engine torque 
+d=8;                    //[in] Crankshaft effective diameter
+
+F=T/(d/2);              //[lb] Force exerted by piston
+
+A=%pi*(2^2)/4;          //[in^2] Area of cross section of piston
+P=F/A;                  //[lb/in^2] Pressure in cylinder
+
+mprintf('\n\n Pressure inside cylinder %f lb/in^2',P);
diff --git a/2921/CH20/EX20.1/Ex20_1.sce b/2921/CH20/EX20.1/Ex20_1.sce
new file mode 100755
index 000000000..315c9aaae
--- /dev/null
+++ b/2921/CH20/EX20.1/Ex20_1.sce
@@ -0,0 +1,12 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-20.1 Page No.431\n');
+
+//L10 design life
+Cd=5050;
+Pd=2400;
+k=3;
+Ld1=(Cd/Pd)^k*10^6;
+Ld=Ld1/(1750*60);
+
+mprintf('\n L10 design life = %f hr.',Ld);
diff --git a/2921/CH20/EX20.2/Ex20_2.sce b/2921/CH20/EX20.2/Ex20_2.sce
new file mode 100755
index 000000000..af6c7f4df
--- /dev/null
+++ b/2921/CH20/EX20.2/Ex20_2.sce
@@ -0,0 +1,18 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-20.2 Page No.432\n');
+
+//Dynamic load capacity
+T=200;
+n=1750;
+L=T*n*60/10^6;
+Pd=2400;
+Ld=21;
+Lc=1;
+k=1/3;
+
+Cd=Pd*(Ld/Lc)^k
+
+mprintf('\n Dynamic load capacity required = %f lb.',Cd);
+
+mprintf('\n Bearing 6211 meets this criterion.');
diff --git a/2921/CH20/EX20.3/Ex20_3.sce b/2921/CH20/EX20.3/Ex20_3.sce
new file mode 100755
index 000000000..700ed0fab
--- /dev/null
+++ b/2921/CH20/EX20.3/Ex20_3.sce
@@ -0,0 +1,52 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-20.3 Page No.434\n');
+
+R=1200;
+Ft=500;
+n=1500;
+L10=5000;
+
+//Assume thrust factor=1.6
+
+Y=1.6;
+
+Pd=0.56*R+Y*Ft;
+
+Ld=n*L10*60/10^6;
+Lc=1;
+k=3;
+Cd=Pd*(Ld/Lc)^(1/k);
+
+//For bearing number 6215
+
+Cd1=11400;
+Cs1=9700;
+
+//Verify the assumption for Y
+Ft_Cs1=Ft/Cs1;
+
+Y=(0.056-Ft_Cs1)*(1.99-1.71)/(0.056-0.028)+1.71;
+
+Pd=0.56*R+Y*Ft;
+
+Cd=Pd*(Ld/Lc)^(1/k);
+
+if Cd>Cd1 then
+    mprintf('\n Since Cd of bearing < Cd required, So bearing number 6215 is not acceptable.');    
+end
+
+//For bearing number 6216
+Cd2=12600;
+Cs2=10500;
+
+Ft_Cs2=Ft/Cs2;
+Y=(0.056-Ft_Cs2)*(1.99-1.71)/(0.056-0.028)+1.71;
+
+Pd=0.56*R+Y*Ft;
+
+Cd=Pd*(Ld/Lc)^(1/k);
+
+if Cd<Cd2 then
+    mprintf('\n Since Cd of bearing > Cd required, So bearing number 6215 meets the design criteria.');
+end
diff --git a/2921/CH20/EX20.4/Ex20_4.sce b/2921/CH20/EX20.4/Ex20_4.sce
new file mode 100755
index 000000000..fa42a02bb
--- /dev/null
+++ b/2921/CH20/EX20.4/Ex20_4.sce
@@ -0,0 +1,26 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-20.4 Page No.436\n');
+
+//Thrust factor
+Ft=300;
+Cs=2320;
+Ft_Cs=Ft/Cs;
+
+Y=(0.17-Ft_Cs)*(1.45-1.31)/(0.17-0.11)+1.31;
+
+mprintf('\n Thrust factor = %f ',Y);
+
+V=1.2;
+X=0.56;
+R=1000;
+
+P=V*X*R+Y*Ft;
+
+Cd=3350;
+Pd=1095;
+k=3;
+
+Ld=(Cd/Pd)^k*10^6;
+
+mprintf('\n Life = %f revolutions.',Ld);
diff --git a/2921/CH3/EX3.1/Ex3_1.sce b/2921/CH3/EX3.1/Ex3_1.sce
new file mode 100755
index 000000000..7733b31a9
--- /dev/null
+++ b/2921/CH3/EX3.1/Ex3_1.sce
@@ -0,0 +1,24 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-3.1   Page No-41 \n');
+
+F=20000;               //[lb] Load applied to steel bar
+L=6;                   //[in] Length of steel bar
+d=1;                   //[in] Diameter of steel bar
+A=%pi*(d^2)/4;         //[in^2] Area of cross section of steel bar
+E=30*10^6;             //[lb/in^2] Modulus of elasticity for AISI 1020 hot-rolled steel
+Sy=30000;              //[lb/in^2] Yield limit
+
+S=F/A;                 //[lb/in^2] Stress in bar
+mprintf('\na. Stress in bar=%f lb/in^2.',S);
+
+delta=F*L/(A*E);       //[in] Change in length of bar
+mprintf('\nb. bar shorten by %f in.',delta);
+
+if Sy>S then
+    mprintf('\nc. The stress of %f psi is less than Sy of %f psi, so it will\n   return to its original size because the yield limit was not exceeded.',S,Sy);
+else 
+    mprintf('The bar will not return to its original length')
+end
+
+//Note: The deviation of answer from the answer given in the book is due to round off error.(In the book values are rounded while in scilab actual values are taken)
diff --git a/2921/CH3/EX3.2/Ex3_2.sce b/2921/CH3/EX3.2/Ex3_2.sce
new file mode 100755
index 000000000..ca43440b7
--- /dev/null
+++ b/2921/CH3/EX3.2/Ex3_2.sce
@@ -0,0 +1,45 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-3.2 Page No.43\n');
+
+b=2;                      //[in] Width of beam
+h=2;                      //[in] Height of beam
+I=(b*h^3)/12;             //[in^4] Moment of inertia
+F=3000;                   //[lb] Load applied to beam
+L=36;                     //[in] Length of beam
+c=1;                      //[in] Distance of outer most fiber from neutral axis
+E=30*10^6;                //[lb/in^2] Modulus of elasticity
+Sy=30000;                 //[lb/in^2] Yield strength
+Su=55000;                 //[lb/in^2] Ultimate strength
+SF=2;                     //[] Safety factor based on ultimate stress
+
+M=F*L/4;                  //[lb*in] Bending moment
+S=(M/I)*c;                //[lb/in^2] Bending stress
+
+//Note-In the book I=1.33 in^4 is used instead of I=1.3333333 in^2
+
+mprintf('\na. The maximum stress in beam is %f lb/in^2',S);
+
+delta=-F*L^3/(48*E*I);     //[in] Maximum deflection in this beam
+
+mprintf('\nb. The maximum deflection in this beam is %f in.',delta);
+
+if Sy>S then
+    mprintf('\nc. Yes, the stress of %f lb/in^2 is less than the yield of Sy=%f lb/in^2.',S,Sy);
+else
+    mprintf('\nc. No, the stress of %f lb/in^2 is greater than the yield of Sy=%f lb/in^2',S,Sy);
+end
+
+Sall=Su/SF;                //[lb/in^2] Allowable stress
+
+if Sall>S then
+    mprintf('\nd. It is acceptable because allowable stress is greater than the acttual stress of %f lb/in^2.',S);
+else
+    mprintf('\nd. Design is not acceptable because allowable stress is less than the actual stress of %f lb/in^2.',S)
+end
+
+//Note: The deviation of answer from the answer given in the book is due to round off error.(In the book values are rounded while in scilab actual values are taken)
+
+
+
+
diff --git a/2921/CH3/EX3.3/Ex3_3.sce b/2921/CH3/EX3.3/Ex3_3.sce
new file mode 100755
index 000000000..4ecf77239
--- /dev/null
+++ b/2921/CH3/EX3.3/Ex3_3.sce
@@ -0,0 +1,16 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-3.3 Page No.45\n');
+
+Su=80*10^3;          //[lb/in^2] Ultimate strength
+d=0.5;               //[in] Diameter of pin
+As=%pi*d^2/4;        //[in^2] Area of cross section of pin
+F=20*10^3;           //[lb] Load acting
+
+Ss=F/(2*As);         //[lb/in^2] Shear stress
+
+if 0.5*Su>=Ss & 0.6*Su>=Ss then
+    mprintf('Pin would not fail');
+else
+    mprintf('\n Actual stress is too high and the pin would fail.');
+end
diff --git a/2921/CH3/EX3.4/Ex3_4.sce b/2921/CH3/EX3.4/Ex3_4.sce
new file mode 100755
index 000000000..ff6d87e2c
--- /dev/null
+++ b/2921/CH3/EX3.4/Ex3_4.sce
@@ -0,0 +1,32 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-3.4 Page No.46\n');
+
+hp=10;             //[hp] Power transmitted
+rpm=1750;          //[rpm] Turning speed
+d=0.5;             //[in] Diameter of shaft
+L=12;              //[in] Length of shaft
+G=11.5*10^6        //[lb/in^2] shear modulus of elasticity
+Su=62000;          //[lb/in^2] 
+
+T=63000*hp/rpm;    //[in*lb] Torque transmitted
+Z=%pi*d^3/16;      //[in^3] Polar section modulus
+Ss=T/Z;            //[lb/in^2] Torsional shear stress
+
+//Note- In the book Z=0.025 in^3 is used instead of Z=0.0245437 in^3
+
+mprintf('\na. Stress in the shaft is %f lb/in^2.',Ss)
+
+J=%pi*d^4/32;      //[in^4] Polar moment of inertia
+theta=T*L/(J*G);   //[radians] 
+
+//Note- In the book J=0.0061 in^4 is used instead of J=0.0061359 in^4
+
+mprintf('\nb. The angular deflection of shaft would be %f radians',theta);
+
+SF=3;               //[] Safety factor based on ultimate strength
+
+Zd=T/(0.5*Su/SF);   //[in^3] Polar section modulus required for SF=3
+Dd=(16*Zd/%pi)^(1/3); //[in] Diameter of shaft required Z=%pi*d^3/16
+
+mprintf('\nc. Diameter of shaft required is %f in.',Dd);
diff --git a/2921/CH3/EX3.5/Ex3_5.sce b/2921/CH3/EX3.5/Ex3_5.sce
new file mode 100755
index 000000000..2648cc2e5
--- /dev/null
+++ b/2921/CH3/EX3.5/Ex3_5.sce
@@ -0,0 +1,43 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-3.5 Page No.53\n');
+
+L=30;                      //[in] Length of link
+d=5/8;                     //[in] Diameter of link
+I=%pi*d^4/64;              //[in^4] Moment of inertia
+A=%pi*d^2/4;               //[in^2] Area of cross section
+E=30*10^6;                 //[lb/in^2] Modulus of elasticity
+
+r=sqrt(I/A);               //[in] Radius of gyration
+
+mprintf('\n The radius of gyration %f in.',r);
+
+K=1;                       //[] End support condition factor
+
+Le=K*L;                    //[in] Effective length
+
+mprintf('\n Effective length is %f in',Le);
+
+SR=Le/r;                   //[] Slenderness ratio
+
+mprintf('\n Slenderness ratio is %f.',SR)
+
+Sy=42000;                 //[lb/in^2] Yield strength
+
+Cc=sqrt(2*%pi^2*E/Sy);    //[] Column constant
+
+mprintf('The column constant is %f.',Cc);
+
+if SR>Cc then
+    mprintf('\n Slenderness ratio is greater than column constant, so use the euler formula')
+end
+
+I=%pi*d^4/64;             //[in^4] Moment of inertia
+
+mprintf('\n The moment of inertia is %f in^4',I);
+
+Pc=%pi^2*E*I/Le^2;        //[lb] Critical force
+
+//Note- In the book I=0.0075 in^4 is used instead of I=0.0074901 in^4
+
+mprintf('\n The critical force is %f lb.',Pc);
diff --git a/2921/CH3/EX3.6/Ex3_6.sce b/2921/CH3/EX3.6/Ex3_6.sce
new file mode 100755
index 000000000..f62d9a4a8
--- /dev/null
+++ b/2921/CH3/EX3.6/Ex3_6.sce
@@ -0,0 +1,34 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-3.6 Page No.55\n');
+
+L=60;                    //[in] Length of column
+Sy=36000;                //[lb/in^2] Yield strength
+SF=2;                    //[]Safty factor
+E=30*10^6;               //[lb/in^2] Modulus of elasticity
+
+A=2.26;                  //[in^2] Area of cross section (Appendix 5.4)
+I=0.764;                 //[in^4] Moment of inertia (Appendix 5.4)
+
+r=sqrt(I/A);             //[in] Radius of gyration
+
+K=0.65;                  //[] End support condition factor from Figure 3.8
+Le=K*L;                  //[in] Effective length
+
+mprintf('\n The effective length is %f in.',Le);
+
+SR=Le/r;                 //[] Slenderness ratio
+
+mprintf('\n The slenderness ratio is %f.',SR);
+
+Cc=sqrt(2*%pi^2*E/Sy);   //[] Column constant
+
+mprintf('\n The column constant is %f.',Cc);
+
+if Cc>SR then
+    mprintf('\n The column constant is greater than slenderness ratio, so use the Johnson formula.');
+end
+
+F=(A*Sy/SF)*(1-Sy*SR^2/(4*%pi^2*E));
+
+mprintf('\n The acceptable load for a safty factor of 2 is %f lb.',F);
diff --git a/2921/CH4/EX4.1/Ex4_1.sce b/2921/CH4/EX4.1/Ex4_1.sce
new file mode 100755
index 000000000..1dd82f3eb
--- /dev/null
+++ b/2921/CH4/EX4.1/Ex4_1.sce
@@ -0,0 +1,21 @@
+clc;

+clear;

+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-4.1   Page 66 ')

+ 

+D=2;               //[in] Dia. of short column

+F=10000;          //[lb] Load applied

+L=15;              //[in] Length of column

+e=2;               //[in] Offset of load

+

+A=(%pi*D^2)/4;      //[in^2] Area of cross section of column

+SA=F/A;             //[lb/in^2] Axial Stress

+

+Z=(%pi*D^3)/32;     //[in^4] Section modulus for bending

+M=F*e;              //[lb*in] Bending moment

+SB=M/Z;             //[lb/in^2] Bemding stress

+

+S=-SA-SB;           //S=(+-)SA+(+-)SB Max. stress

+

+//The bending stress and axial stress are added on inner side of column 

+

+mprintf('\n\n Maximum stress in column is %f lb/in^2.\n',S)

diff --git a/2921/CH4/EX4.2/Ex4_2.sce b/2921/CH4/EX4.2/Ex4_2.sce
new file mode 100755
index 000000000..3c943b29b
--- /dev/null
+++ b/2921/CH4/EX4.2/Ex4_2.sce
@@ -0,0 +1,14 @@
+clc;

+clear;

+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-4.2   Page 67 ')

+

+F1=800;             //[lb] Vertical force

+F2=600;             //[lb] Horizontal force

+D=0.5;              //[in] Pin diameter

+A=(%pi*D^2)/4;     //[in^2] Area of cross section of pin

+

+F=sqrt(F1^2+F2^2);   //[lb] Resultant force on pin

+S=F/A;               //[lb/in^2] Shear stress in pin

+

+//If forces were not perpendicular, they would be added vectorially.

+mprintf('\n\n Shear stress in pin is %f lb/in^2.',S);

diff --git a/2921/CH4/EX4.3/Ex4_3.sce b/2921/CH4/EX4.3/Ex4_3.sce
new file mode 100755
index 000000000..b1e9d0f19
--- /dev/null
+++ b/2921/CH4/EX4.3/Ex4_3.sce
@@ -0,0 +1,25 @@
+clc;

+clear;

+mprintf('MACHINE DESIGN\n Timothy H. Wentzell, P.E.\n Example 4.3   Page no 68');

+

+P=50;            //[hp] Power transmitted

+N=300;           //[rpm] Speed

+D=10;            //[in] Effective pitch diameter of sprocket

+d=1;             //[in] Diameter of shaft from figure 4.3

+Z=(%pi*d^3)/16;  //[in^3] Section modulus of shaft

+A=(%pi*d^2)/4;   //[in^2] Area of cross section

+

+T=(63000/N)*P;  //[lb*in] Torque required to transmit power

+F=T/(D/2);       //[lb] Driving force in chain

+

+Ss=F/A;          //[lb/in^2] Shear stress in shaft

+

+St=T/Z;          //[lb/in^2] Torsional stress in shaft

+

+S=Ss+St;         //[lb/in^2] Resultant stress

+

+//Note-There is mistake in addition of Ss and St.

+

+//This value would be compared to shear stress allowable for shaft material

+

+mprintf('\n\n The combined stress in 1 inch diameter shaft is %f lb/in^2.',S);

diff --git a/2921/CH4/EX4.4/Ex4_4.sce b/2921/CH4/EX4.4/Ex4_4.sce
new file mode 100755
index 000000000..f80a3856e
--- /dev/null
+++ b/2921/CH4/EX4.4/Ex4_4.sce
@@ -0,0 +1,35 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN\n Timothy H. Wentzell, P.E.\n Example 4.4  Page no 71')
+
+P=20;             //[hp] Power transmitted by chain drive
+n=500;            //[rpm] speed
+d=8;              //[in] Pitch diameter of sprocket
+fos=2;
+D=1.25;           //[in] Diameter of shaft
+L=12;             //[in] Distance between two supporting bearings
+Z1=%pi*D^3/16;    //[in^3] Section modulus for torsion
+Z2=%pi*D^3/32;    //[in^3] Section modulus for bending
+
+T=63000*P/n;      //[in*lb] Torque on shaft
+
+F=T/(d/2);        //[lb] Force in chain
+
+M=F*L/4;          //[in*lb] Bending moment in shaft
+
+Ss=T/Z1;          //[lb/in^2] Torsional shear stress
+
+Sb=M/Z2;          //[lb/in^2] Bending normal stress
+
+//Note- In the book Sb=9860 lb/in^2 is used instead of Sb=9856.7075 lb/in^2
+
+S=(Sb/2)+sqrt(Ss^2+(Sb/2)^2);  //[lb/in^2] Combined max. stress
+
+Sy=30000;         //[lb/in^2]From APPENDIX 4 Page no-470 for AISI 1020 and Hot-rolled steel
+FOS=(Sy/2)/S;     //[]Actual factor of safty
+
+if S < Sy/2 then  //Strength is greater than combined stress so design is safe
+    mprintf('\n\n Design is acceptable and Combined stress is %f lb/in^2',S);
+else 
+    mprintf('\n\n Design is not acceptable');
+end
diff --git a/2921/CH5/EX5.1/Ex5_1.sce b/2921/CH5/EX5.1/Ex5_1.sce
new file mode 100755
index 000000000..1ecd0a97e
--- /dev/null
+++ b/2921/CH5/EX5.1/Ex5_1.sce
@@ -0,0 +1,34 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-5.1 Page No.93\n');
+
+SF=2;                     //[] Safety factor
+F=500;                    //[lb] Load
+L=40;                     //[in] Length of shaft
+Su=95000;                 //[lb/in^2] Ultimate strength (Appendix 4)
+Sy=60000;                 //[lb/in^2] Yield strength (Appendix 4)
+
+Mmax=F*L/4;               //[lb*in] Maximum bending moment
+Mmin=-F*L/4;              //[lb/in^2] Minimum bending moment
+
+Csurface=1;               //[] As surface is polished
+Csize=0.85;               //[] Assuming 0.5<D<2
+Ctype=1;                  //[] Bending stress
+
+Sn=Csize*Csurface*Ctype*(0.5*Su); //[lb/in^2] Endurance limit
+
+if Mmax==abs(Mmin) then
+    Sm=0;                //[lb/in^2] Mean stress
+end
+
+Sa=Sn/SF;                //[lb/in^2] As (1/SF)=(Sm/Sy)+(Sa/Sn) from soderberg equation
+
+Sa_Z=(Mmax-Mmin)/2;      //[lb*in^2] Product of altenating stress and section modulus
+
+Z=Sa_Z/Sa;               //[in^4] Section modulus
+
+D=(32*Z/%pi)^(1/3);      //[in] Diameter of shaft
+
+D1=1.375;                //[in] Next higher available is 1.375 in. so use D1
+
+mprintf('\n The required diameter of rotating shaft is %f in.', D1);
diff --git a/2921/CH5/EX5.2/Ex5_2.sce b/2921/CH5/EX5.2/Ex5_2.sce
new file mode 100755
index 000000000..3f7c59791
--- /dev/null
+++ b/2921/CH5/EX5.2/Ex5_2.sce
@@ -0,0 +1,30 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-5.2 Page No.95\n');
+
+Su=90000;                  //[lb/in^2] Ultimate strength (Appendix 8)
+Sy=37000;                  //[lb/in^2] Yield strength (Appendix 8)
+Sni=34000;                 //[lb/in^2] Endurance limit (Appendix 8)
+SF=1.6;                    //[] Safety factor
+
+F=1000;                    //[lb] Load
+L=12;                      //[in] Length of cantilever beam
+
+Mmax=F*L;                  //[lb*in] Maximum bending moment
+Mmin=0;                    //[lb*in] Minimum bending moment
+
+Csize=0.85                 //[] Assuming 0.5<D<2 in
+Ctype=1;                   //[] Bending stress
+Csurface=1;                //[] As surface is polished
+
+Malt=(Mmax-Mmin)/2;        //[lb*in] Alternating bending moment
+
+Mmean=(Mmax+Mmin)/2;       //[lb*in] Mean bending moment
+
+Sn=Csize*Csurface*Ctype*Sni; //[lb/in^2] Modified endurance limit
+
+Z=((Mmean/Sy)+(Malt/Sn))*SF; //[in^3] Section modulus
+
+D=(32*(Z)/%pi)^(1/3);        //[in] Diameter of bar
+
+mprintf('\n The required diameter of bar using the soderberg method is %f in.',D);
diff --git a/2921/CH5/EX5.3/Ex5_3.sce b/2921/CH5/EX5.3/Ex5_3.sce
new file mode 100755
index 000000000..c97f70acc
--- /dev/null
+++ b/2921/CH5/EX5.3/Ex5_3.sce
@@ -0,0 +1,32 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-5.3 Page No.97\n');
+
+Su=90000;                  //[lb/in^2] Ultimate strength (Appendix 8)
+Sy=37000;                  //[lb/in^2] Yield strength (Appendix 8)
+Sni=34000;                 //[lb/in^2] Endurance limit (Appendix 8)
+SF=1.6;                    //[] Safety factor
+
+F=1000;                    //[lb] Load
+L=12;                      //[in] Length of cantilever beam
+
+Mmax=F*L;                  //[lb*in] Maximum bending moment
+Mmin=0;                    //[lb*in] Minimum bending moment
+
+Csize=0.85                 //[] Assuming 0.5<D<2 in
+Ctype=1;                   //[] Bending stress
+Csurface=1;                //[] As surface is polished
+
+Malt=(Mmax-Mmin)/2;        //[lb*in] Alternating bending moment
+
+Mmean=(Mmax+Mmin)/2;       //[lb*in] Mean bending moment
+
+Sn=Csize*Csurface*Ctype*Sni; //[lb/in^2] Modified endurance limit
+
+Z=((Mmean/Su)+(Malt/Sn))*SF; //[in^3] Section modulus
+
+D=(32*(Z)/%pi)^(1/3);        //[in] Diameter of bar
+
+mprintf('\n The required diameter of bar using the soderberg method is %f in.',D);
+
+//Note that the modified Goodman results in a less conservative size as would be expected from figure 5.10
diff --git a/2921/CH5/EX5.4/Ex5_4.sce b/2921/CH5/EX5.4/Ex5_4.sce
new file mode 100755
index 000000000..40714fa23
--- /dev/null
+++ b/2921/CH5/EX5.4/Ex5_4.sce
@@ -0,0 +1,26 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-5.4 Page No.98\n');
+
+Su=95000;              //[lb/in^2] Ultimate strength
+Sy=60000;              //[lb/in^2] Yield strength
+SF=1.5;                //[] Safety factor
+
+Fmax=1000;            //[lb] Maximum load
+Fmin=-6000;           //[lb] Minimum load
+
+Fmean=(Fmax+Fmin)/2;   //[lb] Mean load
+Fmean=abs(Fmean);      //[lb] Considering absolute value
+Falt=(Fmax-Fmin)/2;    //[lb] Alternating load
+
+Csize=1                //[] Assuming b<0.5 in
+Ctype=0.8              //[] Axial stress
+Csurface=0.86          //[] Machined surface Figure 5.7b
+
+Sn=Csize*Csurface*Ctype*(0.5*Su); //[lb/in^2] Modified endurance limit
+
+A=((Fmean/Sy)+(Falt/Sn))*SF;      //[in^2] Area of cross section of rod
+
+b=sqrt(A);                        //[in] Side of square cross section
+
+mprintf('\n The required square size in the center section is %f in.',b);
diff --git a/2921/CH5/EX5.5/Ex5_5.sce b/2921/CH5/EX5.5/Ex5_5.sce
new file mode 100755
index 000000000..2810d5d77
--- /dev/null
+++ b/2921/CH5/EX5.5/Ex5_5.sce
@@ -0,0 +1,31 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-5.5 Page No.100\n');
+
+Su=80000;                 //[lb/in^2] Ultimate strength
+Sy=71000;                 //[lb/in^2] Yield strength
+
+D=0.6;                    //[in] Diameter of shaft
+d=0.5;                    //[in] Diameter of shaft at notch
+r=0.05;                   //[in] Radius of notch
+Z=%pi*d^3/16;             //[in^3] Polar section modulus
+Tmax=200;                 //[lb*in] Maximum load
+Tmin=0;                   //[lb*in] Minimum load
+
+Smax=Tmax/Z;              //[lb/in^2] Maximum stress
+Smin=Tmin/Z;              //[lb/in^2] Minimum stress
+
+Smean=(Smax+Smin)/2;      //[lb/in^2] Mean stress
+Salt=(Smax-Smin)/2;       //[lb/in^2] Alternating stress
+
+Csize=0.85;               //[] Assume 0.5<D<2 in
+Csurface=0.88;            //[] Machined surface Figure 5.7b
+Ctype=0.6;                //[] Torsional stress
+
+Sn=Csize*Csurface*Ctype*(0.5*Su);  //[lb/in^2] Modified endurance limit
+
+Kt=1.32;                  //[] (D/d)=1.2, (r/d)=0.1 from Appendix 6c
+
+N=inv(Smean/(0.5*Sy)+Kt*Salt/Sn);  //[] Safety factor
+
+mprintf('\n The factor of safety for this design is %f',N);
diff --git a/2921/CH5/EX5.6/Ex5_6.sce b/2921/CH5/EX5.6/Ex5_6.sce
new file mode 100755
index 000000000..9767b4732
--- /dev/null
+++ b/2921/CH5/EX5.6/Ex5_6.sce
@@ -0,0 +1,20 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-5.6 Page No.102\n');
+
+//From Example Problem 5.5
+Sy=71000;                 //[lb/in^2] Yield strength
+Smax=8148.7331 ;          //[lb/in^2] Maximum stress
+Smin=0;                   //[lb/in^2] Minimum stress
+Smean=(Smax+Smin)/2;      //[lb/in^2] Mean stress
+Salt=(Smax-Smin)/2;       //[lb/in^2] Alternating stress
+Sn=18000;                 //[lb/in^2] Modified endurance strength
+Kt=1.32                   //[] Stress concentration factor
+
+Nd=100000;                //[cycles] Desired life
+
+Snn=Sn*(10^6/Nd)^0.09;          //[lb/in^2]
+
+N=inv(Smean/(0.5*Sy)+Kt*Salt/Snn);  //[] Factor of safety
+
+mprintf('\n The new factor of safety for this condition is %f.',N);
diff --git a/2921/CH6/EX6.1/Ex6_1.sce b/2921/CH6/EX6.1/Ex6_1.sce
new file mode 100755
index 000000000..8bc582eae
--- /dev/null
+++ b/2921/CH6/EX6.1/Ex6_1.sce
@@ -0,0 +1,14 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-6.1 Page No.120\n');
+
+As=0.334;              //[in^2] Tensile stress area (Table 6.1)
+Sp=85000;              //[lb/in^2] Proof strength (Table 6.3)
+D=3/4;                 //[in] Nominal diameter of thread
+
+Fi=0.85*As*Sp;         //[lb] Desired intial preload
+C=0.2;                 //[] Torque coefficient
+
+T=C*D*Fi;              //[in*lb] Torque
+
+mprintf('\n The required torque is %f lb*in.',T);
diff --git a/2921/CH6/EX6.2/Ex6_2.sce b/2921/CH6/EX6.2/Ex6_2.sce
new file mode 100755
index 000000000..c4d4f29b4
--- /dev/null
+++ b/2921/CH6/EX6.2/Ex6_2.sce
@@ -0,0 +1,16 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-6.2 Page No.121\n');
+
+L=5;                   //[in] Length of engagement
+E=30*10^6;             //[lb/in^2] Modulus of elasticity
+As=0.334;              //[in^2] Tensile stress area (Table 6.1)
+Sp=85000;              //[lb/in^2] Proof strength (Table 6.3)
+Fi=0.85*As*Sp;         //[lb] Desired intial preload
+
+Delta=Fi*L/(As*E)      //[in] Elongation
+
+pitch=0.1;             //[in] Pitch for 3/4 UNC
+TA=Delta*360/pitch;    //[Degree] Torque angle
+
+mprintf('\n The angle of rotation needed is %f degree.',TA);
diff --git a/2921/CH6/EX6.3/Ex6_3.sce b/2921/CH6/EX6.3/Ex6_3.sce
new file mode 100755
index 000000000..ebaea175a
--- /dev/null
+++ b/2921/CH6/EX6.3/Ex6_3.sce
@@ -0,0 +1,12 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-6.3 Page No.122\n');
+
+Alpha=6.5*10^-6;       //[in/(in*F)] Thermal expansion coefficient (Appendix 8)
+L=5;                   //[in] Length of engagement
+
+Delta=0.01204;       //[Degree] Elongation
+
+DT=Delta/(Alpha*L);    //[F] The temperature we would need to heat this bolt above the sevice temperature
+
+mprintf('\n The temperature we would need to heat this bolt above the sevice temperature is %f F.',DT);
diff --git a/2921/CH6/EX6.4/Ex6_4.sce b/2921/CH6/EX6.4/Ex6_4.sce
new file mode 100755
index 000000000..94e51bf46
--- /dev/null
+++ b/2921/CH6/EX6.4/Ex6_4.sce
@@ -0,0 +1,30 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-6.4 Page No.124\n');
+
+Dp=20;                 //[in] Pressure vessel head diameter
+Ds=1.25;               //[in] Stud diameter
+Ls=6;                  //[in] Stud length
+Af=50;                 //[in^2] Clamped area of flanges
+
+E=30*10^6;             //[lb/in^2] Modulus of elasticity
+C=0.15;                //[] Torque coefficient
+Si=120000;             //[lb/in^2] Proof strength (Table 6.3)
+A=1.073;               //[in^2] Tensile stress area (Table 6.1)
+
+Fi=0.9*Si*A;           //[lb] Desired intial load
+
+T=C*Ds*Fi;             //[lb*in] Torque
+
+mprintf('\n1. The required torque is %f lb*in.',T);
+
+Pp=500;                 //[lb/in^2] Pressure inside the pressure vessel
+Ap=%pi*Dp^2/4;          //[in^2] Pressure vessel head cross section area
+
+Kb=A*E/Ls;              //[lb/in] Stiffness per stud
+Kf=Af*E/Ls;             //[lb/in] Stiffness per flange
+Fe=Pp*Ap;               //[lb] Force on pressure vessel head
+
+Ft=10*Fi+(10*Kb/(10*Kb+Kf))*Fe;  //[lb] Total load on the bolt
+
+mprintf('\n2. The total load on the bolt is %f lb.',Ft);
diff --git a/2921/CH7/EX7.1/Ex7_1.sce b/2921/CH7/EX7.1/Ex7_1.sce
new file mode 100755
index 000000000..892dd3810
--- /dev/null
+++ b/2921/CH7/EX7.1/Ex7_1.sce
@@ -0,0 +1,18 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-7.1 Page No.137\n');
+
+D=2;                  //[in] Diameter of bar
+W=500;                //[lb] Weight
+h=1;                  //[in] Height from which the weight falls
+A=%pi*D^2/4;          //[in^2] Area of cross section of bar
+L=10;                 //[in] Length of bar
+E=30*10^6;            //[lb/in^2] Modulus of elasticity
+
+S=(W/A)+(W/A)*(1+(2*h*E*A/(L*W)))^(0.5);  //[lb/in^2] Stress in the bar
+
+mprintf('\n Stress in the bar is %f lb/in^2.',S);
+
+Delta=S*L/E;          //[in] Deflection
+
+mprintf('\n Deflecton in the bar is %f in.',Delta);
diff --git a/2921/CH7/EX7.2/Ex7_2.sce b/2921/CH7/EX7.2/Ex7_2.sce
new file mode 100755
index 000000000..b592e37fe
--- /dev/null
+++ b/2921/CH7/EX7.2/Ex7_2.sce
@@ -0,0 +1,24 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-7.2 Page No.139\n');
+
+W=2000;             //[lb] Weight of automobile
+L=36;               //[in] Length of stop
+D=2;                //[in] Diameter of steel bar
+V=5*5280*12/3600;   //[in/s] Velocity of automobile
+
+A=%pi*D^2/4;        //[in^2] Area of cross section of bar
+E=30*10^6;          //[lb/in^2] Modulus of elasticity
+
+k=A*E/L;            //[lb/in] Stiffness of the bar
+g=386;              //[in/s^2] Acceleration due to gravity
+
+Delta=sqrt(2/k*W*(V^2/(2*g)+0));  //[in] Deflection
+
+mprintf('\n The deflection in the bar is %f in.',Delta);
+
+S=Delta*E/L;        //[in] Stress in the bar
+
+//Note-In the book Delta=0.124 is used instead of Delta=0.123800
+
+mprintf('\n The stress in the bar is %f lb/in^2.',S);
diff --git a/2921/CH7/EX7.3/Ex7_3.sce b/2921/CH7/EX7.3/Ex7_3.sce
new file mode 100755
index 000000000..a92161b0d
--- /dev/null
+++ b/2921/CH7/EX7.3/Ex7_3.sce
@@ -0,0 +1,22 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-7.3 Page No.141\n');
+
+W=3000;                //[lb] Weight of automobile
+L=40*12;               //[in] Length of the beam
+I=64.2;                //[in^4] Moment of inertia of the beam
+Sy=48000;              //[lb/in^2] Yield strength of the beam
+c=8/2;                 //[in] Distance from the outermost fiber to neutral axis
+E=30*10^6;             //[lb/in^2] Modulus of elasticity
+g=32.2;                //[ft/s^2] Acceleration due to gravity
+
+M=I*Sy/c;              //[lb*in] Moment at which beam will yield
+F=4*M/L;               //[lb] Force at which beam will yield
+
+Delta=F*L^3/(48*E*I);  //[in] Deflection
+KE=F*Delta/2;          //[lb*in] Kinetic energy
+
+V=sqrt(2*g*KE/W);      //[in/s] Velocity
+V=V/5280*3600;         //[miles/hr] Velocity
+
+mprintf('\n At %f miles/hr velocity the beam will yield.',V);
diff --git a/2921/CH7/EX7.4/Ex7_4.sce b/2921/CH7/EX7.4/Ex7_4.sce
new file mode 100755
index 000000000..ce013fe1d
--- /dev/null
+++ b/2921/CH7/EX7.4/Ex7_4.sce
@@ -0,0 +1,45 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-7.4 Page No.143\n');
+
+D=3/4;                //[in] Diameter of the bolt
+At=0.334;             //[in^2] Area of thread
+As=%pi*D^2/4;         //[in^2] Area of shank
+
+//Note-In the book As=0.442 in^2 is used instead of As=0.4417865 in.
+
+E=30*10^6;            //[lb/in^2] Modulus of elasticity
+Lt=2;                 //[in] Length of the thread
+Ls=6;                 //[in] Length of the shank
+h=0.03;               //[in] Height from which the weight falls
+W=500;                //[lb] Falling load
+
+Kt=At*E/Lt;           //[lb/in] Stiffness of threaded portion
+Ks=As*E/Ls;           //[lb/in] Stiffness of shank
+
+K=Kt*Ks/(Kt+Ks);      //[lb/in] Overall stiffness
+
+Delta=(W/K)+(W/K)*sqrt(1+2*h*K/W); //[in] Deflection
+
+A=[Ls/E, Lt/E; 0.442, -0.334];
+b=[Delta; 0];
+S=A\b;
+
+S=max(S);            //[lb/in^2] Maximum stress in the bolt
+
+//Note-In the book Delta=0.0048 in is used instead of Delta=0.0047619 in.
+
+mprintf('\n The maximum stress in this bolt is %f lb/in^2.',S);
+
+Ln=8;               //[in] Length when shank has same area as threads
+Kn=At*E/Ln;         //[lb/in] Stiffness
+Deltan=(W/Kn)+(W/Kn)*sqrt(1+2*h*Kn/W);  //[in] Deflection
+S=Deltan*E/Ln;      //[ln/in^2] Stress
+
+mprintf('\n If shank has the same area as threads then stress is %f lb/in^2 and deflection is %f in.',S,Deltan);
+
+
+
+
+
+
diff --git a/2921/CH8/EX8.1/Ex8_1.sce b/2921/CH8/EX8.1/Ex8_1.sce
new file mode 100755
index 000000000..07372f967
--- /dev/null
+++ b/2921/CH8/EX8.1/Ex8_1.sce
@@ -0,0 +1,18 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-8.1 Page No.160\n');
+
+Dm=0.625;            //[in] Mean diameter of spring
+F=35;              //[lb] Load
+
+
+K=1.25;           //[] Wahl factor for Dm/Dw=6.25 (figure 8.8)
+Q=190000;         //[lb/in^2] Expected ultimate strength 
+
+LF=0.263;         //[] Loading factor
+
+Dw=(K*8*F*Dm/(LF*%pi*Q))^(1/2.846); //[in] Wire diameter
+
+mprintf('\n The wire diameter of spring is %f in.',Dw);
+
+//Use U.S Steel 12-gage wire: Dw=0.105 in.
diff --git a/2921/CH8/EX8.2/Ex8_2.sce b/2921/CH8/EX8.2/Ex8_2.sce
new file mode 100755
index 000000000..8bbc929c6
--- /dev/null
+++ b/2921/CH8/EX8.2/Ex8_2.sce
@@ -0,0 +1,29 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-8.2 Page No.163\n');
+
+Dw=0.105;          //[in] Wire diameter
+Dm=0.620;          //[in] Mean diameter of spring
+F=35;              //[lb] Load
+G=11.85*10^6;      //[lb/in^2] Shear modulus of elasticity
+Delta=0.5;         //[in] Deflection
+
+Na=Delta*G*Dw^4/(8*F*Dm^3); //[] Number of active coils
+
+Nat=Na+2;          //[] Total number of coils
+
+Lf=2;              //[in] Free length of spring
+
+P=(Lf-2*Dw)/Nat;   //[in] Pitch (Table 8.1)
+
+mprintf('\n Pitch is %f in.',P);
+
+k=G*Dw^4/(8*Dm^3*Na); //[lb/in] Spring rate
+
+mprintf('\n Spring rate is %f lb/in.',k);
+
+mprintf('\n The total number of coils necessary to meet design criteria are %f.',Nat);
+
+//Note: The deviation of answer from the answer given in the book is due to round off error.(In the book values are rounded while in scilab actual values are taken)
+
+//Note: The deviation of answer from the answer given in the book is due to round off error.(In the book values are rounded while in scilab actual values are taken)
diff --git a/2921/CH8/EX8.3/Ex8_3.sce b/2921/CH8/EX8.3/Ex8_3.sce
new file mode 100755
index 000000000..7e257b3d6
--- /dev/null
+++ b/2921/CH8/EX8.3/Ex8_3.sce
@@ -0,0 +1,10 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-8.3 Page No.165\n');
+Lf=2;            //[in] Free length of spring
+Dm=0.620;        //[in] Mean diameter of spring
+
+R=Lf/Dm;         //[] Free lengtth to mean diameter ratio
+
+mprintf('\n The ratio of the free length of spring to mean diameter of spring is %f.',R);
+mprintf(' From Figure 8.9 for squared and ground ends, this is a stable spring.');
diff --git a/2921/CH8/EX8.4/Ex8_4.sce b/2921/CH8/EX8.4/Ex8_4.sce
new file mode 100755
index 000000000..0f35c966d
--- /dev/null
+++ b/2921/CH8/EX8.4/Ex8_4.sce
@@ -0,0 +1,10 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-8.4 Page No.165\n');
+
+F=35;              //[lb] Load
+k=73.3;            //[lb/in] Spring rate
+
+x=F/k;             //[in] Deflection 
+
+mprintf('\n The deflection in the spring would be %f in.',x);
diff --git a/2921/CH8/EX8.5/Ex8_5.sce b/2921/CH8/EX8.5/Ex8_5.sce
new file mode 100755
index 000000000..d4fd3cae7
--- /dev/null
+++ b/2921/CH8/EX8.5/Ex8_5.sce
@@ -0,0 +1,23 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-8.5 Page No.166\n');
+
+b=12;                  //[in] Width of plate
+h=1;                   //[in] Thickness of plate
+L=72;                  //[in] Length of plate
+I=b*h^3/12;            //[in^4] Moment of inertia
+
+Delta=4;               //[in] Deflection
+E=10*10^6;             //[lb/in^2] Modulus of elasticity
+
+F=3*Delta*E*I/L^3;     //[lb] Force
+
+mprintf('\n The force at this point is %f lb.',F);
+
+k=F/Delta;             //[lb/in] Stiffness
+
+mprintf('\n stiffness is %f lb/in.',k);
+
+//Note: The deviation of answer from the answer given in the book is due to round off error.(In the book values are rounded while in scilab actual values are taken)
+
+//Note: The deviation of answer from the answer given in the book is due to round off error.(In the book values are rounded while in scilab actual values are taken)
diff --git a/2921/CH8/EX8.6/Ex8_6.sce b/2921/CH8/EX8.6/Ex8_6.sce
new file mode 100755
index 000000000..1e384df88
--- /dev/null
+++ b/2921/CH8/EX8.6/Ex8_6.sce
@@ -0,0 +1,10 @@
+clc;
+clear;
+mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-8.6 Page No.167\n');
+
+F=322;             //[lb] Force
+Delta=4;           //[in] Deflection
+
+U=F*Delta/2;       //[in*lb] Energy
+
+mprintf('\n The energy from the 4-inch deflection was %f lb*in.',U);