The members AD and CF in Figure P4.4 are made of elastic–perfectly plastic structural stee...

The members AD and CF in Figure P4.4 are made of elastic–perfectly plastic structural steel, and member BE is made of 7075-T6 aluminum alloy (see Appendix A for properties). The members each have a cross-sectional area of 100 mm2. Determine the load P = PY that initiates yield of the structure and the fully plastic load PP for which all the members yield.

FIGURE P4.4