diff options
Diffstat (limited to '3774/CH7')
-rw-r--r-- | 3774/CH7/EX7.1/Ex7_1.sce | 100 | ||||
-rw-r--r-- | 3774/CH7/EX7.10/Ex7_10.sce | 46 | ||||
-rw-r--r-- | 3774/CH7/EX7.2/Ex7_2.sce | 108 | ||||
-rw-r--r-- | 3774/CH7/EX7.3/Ex7_3.sce | 19 | ||||
-rw-r--r-- | 3774/CH7/EX7.4/Ex7_4.sce | 17 | ||||
-rw-r--r-- | 3774/CH7/EX7.6/Ex7_6.sce | 87 | ||||
-rw-r--r-- | 3774/CH7/EX7.7/Ex7_7.sce | 17 | ||||
-rw-r--r-- | 3774/CH7/EX7.8/Ex7_8.sce | 29 | ||||
-rw-r--r-- | 3774/CH7/EX7.9/Ex7_9.sce | 83 |
9 files changed, 506 insertions, 0 deletions
diff --git a/3774/CH7/EX7.1/Ex7_1.sce b/3774/CH7/EX7.1/Ex7_1.sce new file mode 100644 index 000000000..bbd4ed075 --- /dev/null +++ b/3774/CH7/EX7.1/Ex7_1.sce @@ -0,0 +1,100 @@ +// exa 7.1 Pg 195 +clc;clear;close; + +// Given Data +P=20;// kW +N=240;// rpm +tau_s=45;// MPa +tau_b=30;// MPa +sigma_b=60;// MPa +sigma_cs=2*tau_s;// MPa +tau_ci=15;// MPa +//Tmax=1.25*Tm +mu=0.15;// coefficient of friction + +//SHAFT DIAMETER +// P= 2*%pi*N*Tm/60/1000 +Tm=P/(2*%pi*N/60/1000);// N.m +Tmax=1.25*Tm;// N.m +// %pi*d**3*tau_s/16= Tmax +d=(Tmax/(%pi*tau_s/16)*1000)**(1/3);// mm +printf('shaft diameter = %.2f mm. Use d = 50 mm.',d) +d=50;// mm + +// HUB DIAMETER +// Tmax=%pi/16*((d1**4-d**4)/d1)*tau_h +tau_h=tau_ci;// MPa +//d1*(Tmax/(%pi/16)/tau_h)-d1**4=d**4 -- eqn(1) +Tmax=Tmax*1000;// N.mm +p=[1 0 0 -Tmax/(%pi*tau_h/16) -d**4] ;// polynomial coefficients from eqn(1) +d1=roots(p);// roots of poly +d1=d1(1);// mm (taking +ve value) +d1=100;// mm (empirically adopted) +t1=(d1-d)/2;// mm (thickness of hub) +printf('\n thickness of hub = %.f mm',t1) +d4=d+t1;// mm (diameter of recess in flanges) +printf('\n diameter of recess in flanges = %.f mm',d4) +d3=4*d;// mm (outside diameter of protecting flange) +printf('\n outside diameter of protecting flange = %.f mm',d3) + +// Hub length +b=d/4;// mm (width of key) +l=1.5*d;// mm (length of key) +printf('\n width of key = %.1f mm. Use b = 15 mm',b) +b=15;// mm +printf('\n length of key = %.f mm.',l) +t=b;// mm (thickness for square key) +printf('\n thickness for square key = %.f mm',t) +printf('\n Hub length = %.f mm',l) + +//Number of bolts +n=floor(4*d/150+3);// no. of bolts +printf('\n Number of bolts = %.f',n) + +// Bolt diameter +r2=1.5*d;// mm +F=Tmax/r2/n;// N +//%pi/4*db**2*tau_b=F +db=sqrt(F/(%pi/4*tau_b));// mm +printf('\n Bolt diameter = %.2f mm. Use db=12 mm',db) +bolt_dia=db;//mm + +// Bolt diameter based on Tensile load +r3=d3/2;// mm +r4=d4/2;// mm +rf=2/3*((r3**3-r4**3)/(r3**2-r4**2));// mm +//Tmax=n*mu*Pi*rf;// N +Pi=Tmax/(n*mu*rf);// N +// Pi=%pi/4*db**2*sigma_t +sigma_t=sigma_b;// MPa +db=sqrt(Pi/(%pi/4*sigma_t));// mm +printf('\n Bolt diameter (based on Tensile load) = %.1f mm. Use db=15 mm',db) +db=15;// mm (adopted) + +// Flange thickness +t2=0.5*t1+6;// mm (empirically) +printf('\n Flange thickness = %.1f mm. Use t=20 mm',t2) +t2=20;// mm (adopted) +//F=n*db*t2*sigma_c +sigma_ci=F/n/db/t2;// MPa +//2*%pi*d1**2*tau*t2/4=Tmax +tau=Tmax/(2*%pi*d1**2*t2/4);// MPa +printf('\n permissible bearing stress in flange = %.2f MPa < 30 MPa',sigma_ci) +printf('\n shearing of the flange at the junction with hub = %.2f MPa < 15 MPa.',tau) +printf(' Values are acceptable.') + +// Check for crushing of bolt +//n*db*t2*sigma_cb*d2/2=Tmax +d2=d1+d;// mm +db=bolt_dia;//mm +sigma_cb=Tmax/(n*db*t2*d2/2);// MPa +printf('\n permissible crushing strength of bolts = %.1f MPa < 60 MPa.',sigma_cb) +printf(' Hence design is safe.') + +// Thickness of protecting flange +t3=0.5*t2;// mm +printf('\n Thickness of protecting flange = %.f mm', t3) +// Hub overlap +ho=3;// mm (min) +printf('\n Hub overlap = %.f mm (min)',ho) +//Note - Answer for **Bolt diameter based on Tensile load** is calculated wrong in the textbook(error in Pi calculation). diff --git a/3774/CH7/EX7.10/Ex7_10.sce b/3774/CH7/EX7.10/Ex7_10.sce new file mode 100644 index 000000000..459f61a17 --- /dev/null +++ b/3774/CH7/EX7.10/Ex7_10.sce @@ -0,0 +1,46 @@ +// exa 7.10 Pg 212 +clc;clear;close; + +// Given Data +d=35;// mm +d2=125;// mm +n=6;// factor of safety +T=800;// N.m +N=350;// rpm +tau_s=63;// MPa +tau_b=56;// MPa +tau_CI=10;// MPa +tau_k=46;// MPa + +// Diameter of bolts: +F=2*T*10**3/d2/n;// N +//%pi/4*db**2*tau_b=F +db=sqrt(F/(%pi/4*tau_b));// mm +printf('\n (i) Diameter of bolts = %.2f mm. Use 8 mm.',db) + +// Flange thickness +d1=2*d;// mm +//T=%pi/2*d1**2*t2*tau_CI +t2=T*1000/(%pi/2*d1**2*tau_CI);// mm +printf('\n (ii) Flange thickness = %.1f mm. Use t2 = 12 mm',t2) +t2=12;// mm + +//Key dimensions +b=10;// mm (width of key) +t=7;// mm (from tables) +//T=l*b*tau_k*d/2 +l=T*10**3/(b*tau_k*d/2);// mm +l=ceil(l);// mm +printf('\n (iii) Length of key = %.f mm\n\t\td=%.f mm\n\t\tb=%.f mm',l,d,b) + +// Hub length +lh=l;// mm (length of hub) +printf('\n (iv) Hub length = %.f mm',l) +tau_c=T*10**3/(%pi/16*(d1**4-d**4)/d1);// N/mm.sq. +printf('\n shear stress in hub = %.2f N/mm.sq.',tau_c) +printf('It is nearly equal to %.f N/mm.sq.',tau_CI) +printf('\n hence design parameters are fine.') + +// Power transmitted +P=2*%pi*N*T/60/10**3;// kW +printf('\n (v) Power transmitted = %.2f kW',P) diff --git a/3774/CH7/EX7.2/Ex7_2.sce b/3774/CH7/EX7.2/Ex7_2.sce new file mode 100644 index 000000000..bcc5fef40 --- /dev/null +++ b/3774/CH7/EX7.2/Ex7_2.sce @@ -0,0 +1,108 @@ +// exa 7.2 Pg 200 +clc;clear;close; + +// Given Data +P=30;// kW +N=750;// rpm +//Tmax=1.2*Tm;// MPa +tau_s=35;// MPa +tau_b=35;// MPa +tau_k=35;// MPa +sigma_cs=70;// MPa +sigma_ck=70;// MPa +sigma_cb=70;// MPa +tau_ci=15;// MPa +pb=0.8;// MPa + +//sigma_cs=2*tau_s;// MPa + +//Tmax=1.5*Tm +mu=0.15;// coefficient of friction + +//SHAFT DIAMETER +// P= 2*%pi*N*Tm/60/1000 +Tm=P/(2*%pi*N/60/1000);// N.m +Tmax=1.2*Tm;// N.m +// %pi*d**3*tau_s/16= Tmax +d=(Tmax/(%pi*tau_s/16)*1000)**(1/3);// mm +printf('shaft diameter = %.2f mm. Use d = 42 mm.',d) +d=42;// mm + +// HUB DIAMETER +// Tmax=%pi/16*((d1**4-d**4)/d1)*tau_h +tau_h=tau_ci;// MPa +//d1*(Tmax/(%pi/16)/tau_h)-d1**4=d**4 -- eqn(1) +Tmax=Tmax*1000;// N.mm +p=[1 0 0 -Tmax/(%pi*tau_h/16) -d**4] ;// polynomial coefficients from eqn(1) +d1=roots(p);// roots of poly +d1=d1(1);// mm (taking +ve value) +d1=2*d;// mm (empirically adopted) +t1=(d1-d)/2;// mm (thickness of hub) +printf('\n thickness of hub = %.f mm',t1) +//d4=d+t1;// mm (diameter of recess in flanges) +//printf('\n diameter of recess in flanges = %.f mm',d4) +d3=4*d;// mm (outside diameter of protecting flange) +printf('\n outside diameter of protecting flange = %.f mm. Use 170 mm',d3) +d3=170;// mm (adopted) + +//Key size & Hub length +b=d/4;// mm (width of key) +l=1.5*d;// mm (length of key) +printf('\n width of key = %.1f mm. Use b = 12 mm',b) +b=12;// mm +printf('\n length of key = %.f mm.',l) +t=b;// mm (thickness for square key) +printf('\n thickness for square key = %.f mm',t) +printf('\n Hub length = %.f mm',l) + +//Number of bolts +n=(0.04*d+3);// no. of bolts +printf('\n Number of bolts = %.2f. Use n=6',n) +n=6;// adopted + +// Bolt diameter +db=0.5*d/sqrt(n);// mm +printf('\n Bolt diameter = %.2f mm. Use db=20 mm for design purpose',db) +db=20;//mm (adopted) +bolt_dia=db;//mm +dsb=24;// mm(shank diameter of bolt for design) + +// Outer diameter of rubber bush +trb=2;// mm (thickness of rubber bush) +tbb=6;// mm (thickness of brass bush) +d3=dsb+2*trb+2*tbb;// mm +d2=d1+d3+2*tbb;// mm (pitch circle diameter of bolts) +printf('\n pitch circle diameter of bolts = %.f mm ',d2) + +// Check of shear in bolt +F=2*Tmax/n/d2;// N +//%pi/4*db*2*tau=F +tau=F/(%pi/4*db**2);//MPa +printf('\n Permissible shear stress in bolts = %.2f MPa < 35 MPa. Hence design is safe.', tau) + +// Length of brush +pb=0.8;// MPa(bearing pressure of brush) +//F=l2*d3*pb; +l2=F/d3/pb;// mm +printf('\n length of bush = %.f mm',l2) + +// Check for pin in bending +c=5;// mm (clearance between two flanges) +l3=(l2-c)/2+c;//mm +//M=%pi/32*db**3*sigma_b & M=F*l3 +sigma_b = F*l3/(%pi/32*db**3);// MPa +printf('\n Bending stress in pin = %.1f MPa',sigma_b) + +// Maximum shear stress in pin +tau_max=sqrt((sigma_b/2)**2+tau**2);//MPa +printf('\n Maximum shear stress in pin = %.2f MPa < 35 MPa. Hence design is safe.',tau_max) + +// Flange thickness +t2=0.5*t1+6;// mm (empirically) +printf('\n Flange thickness = %.1f mm. Use t=18 mm',t2) +t2=18;// mm (adopted) +tau=Tmax/(2*%pi*d1**2*t2/4);// MPa +printf('\n shearing of the flange at the junction with hub = %.2f MPa < 15 MPa.',tau) +printf(' Values are acceptable.') + +//Note - Answer in llast part is calculated wrong in the textbook(error in calculation). diff --git a/3774/CH7/EX7.3/Ex7_3.sce b/3774/CH7/EX7.3/Ex7_3.sce new file mode 100644 index 000000000..681ceb911 --- /dev/null +++ b/3774/CH7/EX7.3/Ex7_3.sce @@ -0,0 +1,19 @@ +// exa 7.3 Pg 204 +clc;clear;close; + +// Given Data +n=8;// no. of spline +d=52;// mm +D=60;// mm +pm=6;// MPa +mu=0.06;// coefficient of friction +N=320;// rpm +P=20;// kW + +T=60*10**3*P/2/%pi/N;// N.m +l=8*T*10**3/pm/n/(D**2-d**2);// mm +printf('length of hub = %.f mm',l) +Rm=(D+d)/4;// mm +F=T*10**3/Rm;// N +Ff=mu*F;//N (Force of friction) +printf('\n Force required to shift the connection = %.1f N',Ff) diff --git a/3774/CH7/EX7.4/Ex7_4.sce b/3774/CH7/EX7.4/Ex7_4.sce new file mode 100644 index 000000000..112ac9a80 --- /dev/null +++ b/3774/CH7/EX7.4/Ex7_4.sce @@ -0,0 +1,17 @@ +// exa 7.4 Pg 204 +clc;clear;close; + +// Given Data +d=75;// mm +tau=50;// MPa +sigma_c=75;// MPa +printf('for key to be equally strong in shear & crushing - \n') +b=d/4;// mm +printf(' b= %.2f mm. Use b=20 mm.',b) +b=20;//mm +//2*b/t=sigma_c/tau for key to be equally strong in shear & crushing +t=2*b/(sigma_c/tau);// mm +printf('\n t=%.2f mm. Use t=27 mm',t) +l= %pi*d**2/8/b;// mm (for key to be equally strong in shear as shaft) +printf('for key to be equally strong in shear as shaft - \n') +printf(' l=%.1f mm. Use l=115 mm',l) diff --git a/3774/CH7/EX7.6/Ex7_6.sce b/3774/CH7/EX7.6/Ex7_6.sce new file mode 100644 index 000000000..915d8510a --- /dev/null +++ b/3774/CH7/EX7.6/Ex7_6.sce @@ -0,0 +1,87 @@ +// exa 7.6 Pg 205 +clc;clear;close; + +// Given Data +P=135;// kW +N=120;// rpm +tau_s=55;// MPa +tau_b=45;// MPa +tau_ci=175;// MPa +sigma_ci=75;// MPa + +//sigma_cs=2*tau_s;// MPa + +//Tmax=1.5*Tm +mu=0.15;// coefficient of friction + +//SHAFT DIAMETER +// P= 2*%pi*N*Tm/60/1000 +Tm=P/(2*%pi*N/60/1000);// N.m +// %pi*d**3*tau_s/16= Tm +d=(Tm/(%pi*tau_s/16)*1000)**(1/3);// mm +d=ceil(d) +printf('shaft diameter = %.2f mm.',d) +Tmax=Tm;// N.m + +// HUB DIAMETER +// Tmax=%pi/16*((d1**4-d**4)/d1)*tau_h +tau_h=tau_ci;// MPa +//d1*(Tmax/(%pi/16)/tau_h)-d1**4=d**4 -- eqn(1) +Tmax=Tmax*1000;// N.mm +p=[1 0 0 -Tmax/(%pi*tau_h/16) -d**4] ;// polynomial coefficients from eqn(1) +d1=roots(p);// roots of poly +d1=d1(1);// mm (taking +ve value) +d1=2*d;// mm (empirically adopted) +t1=(d1-d)/2;// mm (thickness of hub) +printf('\n thickness of hub = %.f mm',t1) +d4=d+t1;// mm (diameter of recess in flanges) +printf('\n diameter of recess in flanges = %.f mm',d4) +d3=4*d;// mm (outside diameter of protecting flange) +printf('\n outside diameter of protecting flange = %.f mm.',d3) + +//Key size & Hub length +b=d/4;// mm (width of key) +l=1.5*d;// mm (length of key) +printf('\n width of key = %.1f mm.',b) +printf('\n length of key = %.f mm.',l) +t=b;// mm (thickness for square key) +printf('\n thickness for square key = %.f mm',t) +printf('\n Hub length = %.f mm',l) + +//Number of bolts +n=ceil(4*d/150+3);// no. of bolts +printf('\n Number of bolts = %.2f.',n) + +// Bolt diameter +r2=1.5*d;// mm +F=Tm*1000/r2/n;//N +//(%pi/4)*db**2*tau_b=F +db=sqrt(F/((%pi/4)*tau_b));// mm +printf('\n Bolt diameter = %.2f mm. Use db=20 mm for design purpose',db) +db=20;// mm (adopted for design) +bolt_dia=db;//mm + +// Flange thickness +t2=0.5*t1+6;// mm (empirically) +printf('\n Flange thickness = %.1f mm. Use t=20 mm',t2) +//F=n*db*t2*sigma_c +sigma_ci=F/n/db/t2;// MPa +//2*%pi*d1**2*tau*t2/4=Tmax +tau=Tmax/(2*%pi*d1**2*t2/4);// MPa +printf('\n permissible bearing stress in flange = %.2f MPa < 75 MPa',sigma_ci) +printf('\n shearing of the flange at the junction with hub = %.2f MPa < 175 MPa.',tau) +printf(' Values are acceptable.') + +// Check for crushing of bolt +//n*db*t2*sigma_cb*d2/2=Tmax +d2=d1+d;// mm +db=bolt_dia;//mm +sigma_cb=Tmax/(n*db*t2*d2/2);// MPa +printf('\n permissible crushing strength of bolts = %.2f MPa < 60 MPa.',sigma_cb) +printf(' Hence design is safe.') +// Thickness of protecting flange +t3=0.5*t2;// mm +printf('\n Thickness of protecting flange = %.f mm', t3) +// Hub overlap +ho=3;// mm (min) +printf('\n Hub overlap = %.f mm (min)',ho) diff --git a/3774/CH7/EX7.7/Ex7_7.sce b/3774/CH7/EX7.7/Ex7_7.sce new file mode 100644 index 000000000..8ec7ff5b3 --- /dev/null +++ b/3774/CH7/EX7.7/Ex7_7.sce @@ -0,0 +1,17 @@ +// exa 7.7 Pg 208 +clc;clear;close; + +// Given Data +d=50;// mm +tau=42;// MPa +sigma_c=72;// MPa +printf('for key to be equally strong in shear & crushing - \n') +b=d/4;// mm +printf(' b= %.2f mm. Use b=15 mm.',b) +b=15;//mm +//2*b/t=sigma_c/tau for key to be equally strong in shear & crushing +t=2*b/(sigma_c/tau);// mm +printf('\n t=%.2f mm. Use t=20 mm',t) +l= %pi*d**2/8/b;// mm (for key to be equally strong in shear as shaft) +printf('\n for key to be equally strong in shear as shaft - \n') +printf(' l=%.2f mm. Use l=70 mm',l) diff --git a/3774/CH7/EX7.8/Ex7_8.sce b/3774/CH7/EX7.8/Ex7_8.sce new file mode 100644 index 000000000..161af8ede --- /dev/null +++ b/3774/CH7/EX7.8/Ex7_8.sce @@ -0,0 +1,29 @@ +// exa 7.8 Pg 208 +clc;clear;close; + +// Given Data +d=25;// mm +N=550;// rpm +P=12;// kW +sigma_yt=400;// N/mm.sq. +sigma_yc=400;// N/mm.sq. +n=2.5;// factor of safety + +// P= 2*%pi*N*T/(60*10**3) +T=P/(2*%pi*N/(60*10**3));// N.m +tau=0.5*sigma_yt;// MPa +tau_d=tau/n;// N/mm.sq. +printf('design shear stress = %.f N/mm.sq.',tau_d) +sigma_d=sigma_yc/n;// N/mm.sq. +printf('\n design crushing strength = %.f N/mm.sq.',sigma_d) +b=d/4;//mm +printf('\n width of key = %.f mm. Use 7mm',b) +b=ceil(d/4);// mm +t=b;// mm +printf('\n thickness of key = %.f mm.',t) +l_s=2*T*10**3/(d*b*tau_d);// mm (length of key based on shear failure) +printf('\n length of key based on shear failure = %.2f mm or %.f mm',l_s, l_s) +l_c=4*T*10**3/(d*t*sigma_d);// mm (length of key based on crushing failure) +printf('\n length of key based on crushing failure = %.2f mm or %.f mm',l_c, l_c) + + diff --git a/3774/CH7/EX7.9/Ex7_9.sce b/3774/CH7/EX7.9/Ex7_9.sce new file mode 100644 index 000000000..c800ac040 --- /dev/null +++ b/3774/CH7/EX7.9/Ex7_9.sce @@ -0,0 +1,83 @@ +// exa 7.9 Pg 209 +clc;clear;close; + +// Given Data +d=36;// mm +P=15;// kW +N=720;// rpm +//Tmax=1.25*Tm +sigma_yt=245;// MPa (for C20 steel) +n=3;// factor of safety +sigma=82;// MPa (Design tensile stress) + +tau=0.577*sigma;// MPa (shear stress) +sigma_u=200;// MPa (for FG 200 cast Iron) +n2=5;// factor of safety (for FG 200 cast Iron) +tau2=20;// MPa shear stress (for FG 200 cast Iron) + +// Max. torque transmitted +//P=2*%pi*N*Tm/(60*10**3) +Tm=P/(2*%pi*N/(60*10**3))*1000;// N.mm +Tmax=1.25*Tm;// N.mm +printf('\n Maximum transmitted torque = %.f N.mm',Tmax) + +// Hub diameter +tau_h=20;// MPa (permissible shear stress in hub) +//Tmax=(%pi/16)*(d1**4-d**4)/d1*tau_h ...eqn(1) +d1=2*d;//mm (empirically) +tau_h=Tmax*1000/((%pi/16)*(d1**4-d**4)/d1);// MPa +t1=(d1-d)/2;// mm (thickness of hub) +printf('\n Hub diameter = %.f mm',d1) +printf('\n Thickness of hub = %.f mm',t1) +d4=d+t1;// mm +printf('\n Diameter of recess in flanges = %.f mm',d4) +d3=4*d;//mm +printf('\n Outside diameter of protecting flange = %.f mm',d3) + +//Hub length +b=d/4;// mm (width of key) +l=1.5*d;// mm (length of key) +printf('\n width of key = %.1f mm.',b) +printf('\n length of key = %.f mm.',l) +t=b;// mm (thickness for square key) +printf('\n thickness for square key = %.f mm',t) +printf('\n Hub length = %.f mm',l) + +//Number of bolts +n=ceil(4*d/150+3);// no. of bolts +printf('\n Number of bolts = %.2f.',n) + +// Bolt diameter +r2=1.5*d;// mm +F=Tmax/r2/n;//N +//(%pi/4)*db**2*tau_b=F +db=sqrt(F/((%pi/4)*tau));// mm +printf('\n Bolt diameter = %.2f mm. Use db=6 mm for design purpose',db) +db=6;// mm (adopted for design) +bolt_dia=db;//mm + +// Flange thickness +t2=0.5*t1+6;// mm (empirically) +printf('\n Flange thickness = %.1f mm. Use t=20 mm',t2) +//F=n*db*t2*sigma_c +sigma_ci=F/n/db/t2;// MPa +//2*%pi*d1**2*tau*t2/4=Tmax +tau=Tmax/(2*%pi*d1**2*t2/4);// MPa +printf('\n permissible bearing stress in flange = %.2f MPa < 40 MPa',sigma_ci) +printf('\n shearing of the flange at the junction with hub = %.2f MPa < 20 MPa.',tau) +printf(' Values are acceptable.') + +// Check for crushing of bolt +//n*db*t2*sigma_cb*d2/2=Tmax +d2=d1+d;// mm +db=bolt_dia;//mm +sigma_cb=Tmax/(n*db*t2*d2/2);// MPa +printf('\n permissible crushing strength of bolts = %.2f MPa < 82 MPa.',sigma_cb) +printf(' Hence design is safe.') +// Thickness of protecting flange +t3=0.5*t2;// mm +printf('\n Thickness of protecting flange = %.f mm', t3) +// Hub overlap +ho=3;// mm (min) +printf('\n Hub overlap = %.f mm (min)',ho) + |