Consider a low-carbon square steel bar 20 mm on a side and 1.7 m long having a material yield point of 275 MPa and E = 200 GPa. An applied axial load gradually builds up from zero to a value such that the elongation of the bar is 15 mm, after which the load is removed. Determine the permanent elongation of the bar after removal of the load. Assume elastic, perfectly plastic behavior as shown in Fig. 1-23. 275 (MPa) 0.00882- C B