Question

As part of the product development process for go-kart drive shaft, the engineer has instrumented a critical area of the shaft with a solid bar. A drive shaft bar is designed to carry a tensile load. The engineer has proposed a circular bar with cross-section having a radius of 26 mm. It carries an axial tensile load of 140 kN. By using equation;

i) Calculate the values of principal stresses at the critical area of the bar.

ii) Determine the rotation of the longitudinal axis of the bar if the normal stress value after the rotation is 50 MPa.

iii) If the load on the bar changed to 264 kN, calculate the new principle stresses.

iv) State the location of principal stresses in part (iii) to be maximum. Give your reason

Answer 1

i) P = 140kN d= 26mm TTx 262 4- 7% 42 Stress element diagram . Principal stresses 2. 办5 = 62,十 67と Tx 릅 243 . 6 8 MRa іり 0e =らOMPa 6- 咏+4 + 1Tok-Fj] cos 2 txy si n29 t 2 2 oyTy o 50 263 63 263-68 cos2e 2e 128-371 8-64-1850 tHence Longituánal arfs is rotated by 64 18 to set normal stress of ら0 MPa ili) iF P 264 KN , then 264x10 -497-241 MPa T/4 x 262

26: 0,180° o and 9o ocation of principal stresses are Ge 497241 = Max: Principal stress occurs at 6-0. Alorf bar- σ2 : O Min principal stress occurs at6-98 ax pr