Problem 5 (Deformation) For shock loading in a ductile material, Table 3-2 recommends the following design stress. The percent elongation of 12%% is in the ductile range. 04 - s./12 = 196 kei/12 = 16 33 ksi = 16 330 psi Because the actual expected stress is below the design stress, the bar should be safe. Axial deformation: Use Equation (5-9). All data are known except the modulus of elasticity, E. From the footnotes of Appendix A-14 we find E = 30 = 106 pai. Then, FL (40 000 lb) (68 5 in) ME (3.14 in' )(30 x 10 1b/in ) -0,029 in Let's solve the above problem for different load values as given below. The tie rods in the press in Figure 3-3 are made of the steel alloy AIS: 5160 OCT 900. Each rod has a diameter of 2:00 in and an initial length of 68 5 in, An axial tensile load of 40 000 Jo is Problem Case Load (2s) Deformation [in) exerted on each rod during operation of the press. Compute the deformation of the rods. Check also if the strength of the material is adequate. Guided Practice 45000 Solution 1 49000 Objective Compute the deformation of the tie rods. Given Rods are steel, AISI 5160 OCT 900, gg = 179 bud gy = 196 bai, 1216 elongation Diameter = 2 55000 D . 2.00 in. Length . L. 68.5 in. Axial force . F= 40 000 lb. Analysis Equation (3-9) will be used to compute deformation. The stress in the rods must be 75000 checked to ensure that it is below the proportional limit and safe under repeated shock loading Results Axial tensile stress: g = FA. Aram " (20in) = 3.14 in . Then, G . 40 000 lb =12 700 pal. 3.14 in Therefore, the stress is well below the proportional limit