Question

Question 6. A) The load, a black box, is fixed at the point B, fig. 6A, and is supported by the weightless bars AB and DB. Draw the free body diagram for the point B. [2 marks] B D Fig. 6A. The diagram of the load and the supporting system. B) A thin-walled cylindrical pipe with an outer diameter of 250 mm and a wall thickness of 3 mm, experiences an internal gauge pressure of 5 MPa. Show with the evidence that the hoop stress must be taken for the structural and safety calculation of the pipe, instead of the longitudinal stress.

Answer 1

(А.). ROD AB & DB are weightless Assuming, mass of Бо ще т. (99). АСС. due to gravity grity = 9 = 9. | m/s 3 NOW, 1 р В T3 TI 09 КУ в Тэ Т - 19 T where, T, , T. wy are Tention in the weightless bars. CSScanned with CamScanner

2. (B.) Given - diameter (d) = 250 mm Thickness (t 3 mm Internas Gauge pressure (P) = 5MPa. NOW, EL *? 6H - Where 64 & EL are HOOP & Longitudina Stress. 64 = pd 5MPa. 250 mm - 2t 2. 3mm 64 = 208.34 MPa 62 = pd ut - 104.167 MPa. CSScanned with CamScanner

3 So, CH = 261 Би > 5 Since, би ية muen larger than El. on other hand, at is directed along circumference, which es may be tensile in Dature. Thus, There, charee to increase in diameter. Therefore, HOOP stress is taken for the struefuray a Bafety purpose. CSScanned with CamScanner