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ME 271 STRENGTH OF MATERIALS Associate Prof Dr Bülent Ekici Example Example Example Example Example Example Example Example Example Example Example 1 A torsion bar spring is made of ASTM grade A-48 cast iron is load as shown. The stress concentration factors are 1.7 for bending and 1.4 for torsion. Determine the diameter d for the load P=25 N and T=10 Nm, using a factor of safety n=2.5. (Sut=170 MPa, Suc=650 MPa) Find the diameter Example 2 A steel rod of diameter d=50 mm (Sy=260 MPa SUT=280 MPa SUC=350 MPa) supports an axial load P=50R, vertical load of 0.2R at the midspan of 2m long cylindrical bar and vertical load R acting at the end of an 0.8 m long arm as shown in figure. Given of a factor of safety n=2, compute the largest permissible value of R, Example 3 Three forces are applied to the machine component ABD, as shown. Knowing that the cross section containing point H has a cross section of 20x40 mm rectangle, determine the principal stresses and the maximum shearing stres at point H. Example 4 The 6 kN force is vertical and the force P is paralel to the z-axis.Knowing that tall=60 MPa,, Determine the smallest permissible diameter of the solid shaft AD. Strength of shaft is 200 MPa T=450 Nm M=573.1 Nm Assume no stress concentration