The pin-jointed structure shown in Fig. P11.21 is constructed of two 0.025-...

The pin-jointed structure shown in Fig. P11.21 is constructed of two 0.025- m-diameter tubes having the following properties: A = 5.4 x 10^-5 m² I = 3.91 x 10^-9 m⁴, E = 210 GPa. The stress–strain curve for the tube

material can be accurately approximated by three straight lines as shown. If the load P is increased until the structure fails, which tube fails first? Describe the nature of the failure and determine the critical load.