Instructions: This exam consists of three problems worth a total of 60 points. T
ID: 2326387 • Letter: I
Question
Instructions: This exam consists of three problems worth a total of 60 points. The only materials permitted are the 3 handouts posted on Pilot, a calculator, and both sides of an 8.5"x11" handwritten crib sheet, which MUST be turned in with the exam. 1. A cantilever spring is loaded with a force F = 5 Ibf, as shown in the figure below. The spring has a rectangular cross section of width w 3/8" and thickness t =3/32".The remaining dimensions are L_1 = 4.5", L_2 = 2" and r = 0.150". Using curved beam theory. Find the stress at the outer surface of the bend. Required for those registered for 6140. optional extra credit for those registered for 4140: find the stress at the inner surface of the bend? Find the maximum shear stress at the outer surface of the bend.Explanation / Answer
F= 5lbf conert to N
22.421N
w = 3/8 inch = 0.9525 cm
t = 3/32 inch= 0.238 cm
L1 = 4.5 inch =11.43cm
L2 = 2 inch = 5.08 cm
r = 0.150 inch = 0.381 cm
1.maximum shear stress
stress max = F/l.b{B/8(H2-h2)+b.h2/8}
= 1604 MPa
2.curved beam thoery
stress at outer surface of beam