3 files changed, 163 insertions, 0 deletions
diff --git a/764/CH7/EX7.21.b/graph7_21.png b/764/CH7/EX7.21.b/graph7_21.png
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+++ b/764/CH7/EX7.21.b/graph7_21.png
diff --git a/764/CH7/EX7.21.b/result7_21.txt b/764/CH7/EX7.21.b/result7_21.txt
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+-->//(Threaded Joints) Example 7.21
+ 
+-->//Maximum internal pressure MAXP (MPa)
+ 
+-->MAXP = 2
+ MAXP  =
+ 
+    2.  
+ 
+-->//Minimum internal pressure MINP (MPa)
+ 
+-->MINP = 0
+ MINP  =
+ 
+    0.  
+ 
+-->//Diameter of the circle on which pressure acts D (mm)
+ 
+-->D = 400
+ D  =
+ 
+    400.  
+ 
+-->//Assume the stiffness of the bolts to be 1N/mm kb
+ 
+-->kb = 1
+ kb  =
+ 
+    1.  
+ 
+-->//Calculate the stiffness of the parts kc (N/mm)
+ 
+-->kc = 4 * kb
+ kc  =
+ 
+    4.  
+ 
+-->//Ultimate tensile strength Sut (N/mm2)
+ 
+-->Sut = 900
+ Sut  =
+ 
+    900.  
+ 
+-->//Yield strength Syt (N/mm2)
+ 
+-->Syt = 700
+ Syt  =
+ 
+    700.  
+ 
+-->//Endurance limit in bending Sdash (N/mm2)
+ 
+-->Sdash = 300
+ Sdash  =
+ 
+    300.  
+ 
+-->//Fatigue stress concentration factor Kf
+ 
+-->Kf = 2.2
+ Kf  =
+ 
+    2.2  
+ 
+-->//Factor of safety fs
+ 
+-->fs = 1.5
+ fs  =
+ 
+    1.5  
+ 
+-->//Number of bolts N
+ 
+-->N = 8
+ N  =
+ 
+    8.  
+ 
+-->//Assume expected reliability (%)
+ 
+-->reliability = 90
+ reliability  =
+ 
+    90.  
+ 
+-->//Assume diameter of the bolt to be less than 7.5mm for Kb to be 1
+ 
+-->d = 1
+ d  =
+ 
+    1.  
+ 
+-->//As Ka is incorporated into Kf, assume the assembly to be ground
+ 
+-->//This is just to obtain a random value of Ka
+ 
+-->op = 1
+ op  =
+ 
+    1.  
+ 
+
+Core cross-section area of the bolt(A) = 85.172067 mm2
+ 
+\ No newline at end of file
diff --git a/764/CH7/EX7.21.b/solution7_21.sce b/764/CH7/EX7.21.b/solution7_21.sce
new file mode 100755
index 000000000..acef2b3bf
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+++ b/764/CH7/EX7.21.b/solution7_21.sce
@@ -0,0 +1,58 @@
+
+function[] = plot_format()
+    //Get the handle of current axes
+    g = gca()
+    //Give labels and set label properties
+    g.labels_font_color=5
+    g.font_size=3
+    g.grid=[1,1]
+    g.box="off"
+endfunction
+
+//Obtain path of solution file
+path = get_absolute_file_path('solution7_21.sce')
+//Obtain path of data file
+datapath = path + filesep() + 'data7_21.sci'
+//Obtain path of function file
+funcpath = path + filesep() + 'functions7_21.sci'
+//Clear all
+clc
+//Execute the data file
+exec(datapath)
+exec(funcpath,[-1])
+//Calculate Ka, Kb and Kc
+[Ka, Kb, Kc] = fluctuate(op, d, reliability)
+//Calculate Kd 
+Kd = 1/Kf
+//Calculate the corrected endurance limit stress Se (N/mm2)
+Se = Kb * Kd * Sdash
+//Plot modified Goodman diagram
+//The common quadrilateral in the plot is the area of concern
+y1 = {Se 0}
+x1 = {0 Sut}
+y2 = {Syt 0}
+x2 = {0 Syt}
+plot(x1,y1,'--*')
+plot(x2,y2,'-*')
+plot_format()
+title('Modified Goodman diagram (Example 7.21)')
+xlabel('sigmaM (N/mm2)')
+ylabel('sigmaA (N/mm2)')
+//Calculate the maximum and minimum force of fluid on cover P (N)
+P1 = (%pi/4)*(D^2)*MAXP
+P2 = (%pi/4)*(D^2)*MINP
+//Calculate the initial pre-load on the bolts Pi (N)
+Pi = 1.3 * P1
+//Calculate the maximum and minimum forces in the bolt (N)
+Pmax = Pi + ((kb/(kb + kc))*P1)
+Pmin = Pi + ((kb/(kb + kc))*P2)
+//Calculate the mean force and force amplitude
+Pm = (Pmax + Pmin)/2
+Pa = (Pmax - Pmin)/2
+//Calculate the actual core cross-section area of the bolts Atotal (mm2)
+Atotal = (Pa + (Pi/((1 + (Sut/Se)) * fs)))/(Sut/((1 + (Sut/Se))*fs))
+//Calculate the cross-section area of each bolt A (mm2)
+A = Atotal/N
+//Choose proper diameter from Table 7.1
+//Print results
+printf('\nCore cross-section area of the bolt(A) = %f mm2\n',A)