A round AB bar (L = 600 mm in length and with Ø = 55 mm of diameter) is machined from the heat-treated AISI 1060 steel (quenched and tempered at T = 1200 °C) will be analysed as a candidate for static structural application in the aerospace sector. A system of external loadings acting on the bar is depicted as in Fig. 1 where the two vertical bars OA and BC (L= 280 mm each) forming a working mechanism comprising OABC and can be assumed to be of a one-piece structure. As such, the effect of stress concentration factors due to geometrical discontinuities can be discounted. A summary of the three loadings are given as follows;

Problem 15 The compound bar shown below is made of a light, strong material with E= 70,000 N/mm². Two forces are applied to the rigid plates connecting the bars. The yield strength is o, = 200 N/mm². The bar has a rectangular cross section with height H = 12.5 mm and thickness t = 1.0 mm. You may neglect the weight of the bars. (a) Calculate the x-direction internal force in segments AB and BC of the compound bar. Show all work. (b) Calculate the total length change of the compound bar. (c) The plane 1-2 represents a lap joint. Calculate the normal stress on the lap joint. L₂= 625 mm A L₁ = 775 mm H = 12.5 mm X 1800 N B 1 H = 12.5 mm =35° 2 F₂ = 1000 N Cross section H-12 H = 12.5 mm t = 1.0 mm