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The Elastic Vector Method. By T. Bart Quimby, P.E., Ph.D. Quimby & Associates. Elastic Method. Move Horizontal Force to Center of Bolt Group. Break force into it’s components. Move Vertical Force to Center of Bolt Group. Combine the Two Moments into One. Find Bolt Stresses due to Moment.
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The Elastic Vector Method By T. Bart Quimby, P.E., Ph.D. Quimby & Associates
Elastic Method Move Horizontal Force to Center of Bolt Group Break force into it’s components Move Vertical Force to Center of Bolt Group Combine the Two Moments into One
Find Bolt Stresses due to Moment Elastic Method fy =Py/(Abnb) fmi = M ri / J fmxi = fmi * dyi/ci fmyi = fmi * dxi/ci fx =Px/(Abnb) Find Bolt Stresses due to Vertical Force Find Bolt Stresses due to Horizontal Force Bolt stresses due to Moment are perpendicular to radial lines from the center of the bolt group
Elastic Method The resultant stress in each fastener equals the vector sum of the stresses applied to it. fi = sqrt[(fyi + fmyi)2 + (fxi + fmxi)2] Pi = fi Ab
Elastic Method • Good • Very easy and straight forward use of Mechanics • Not so Good • Very conservative • Not consistent with test results resulting in a widely variable factor of safety