ISRO Mechanical & Aerospace 2018 - Question 80

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Topic: Machine Design

If an element is loaded as shown in figure below, the Von Mises stress will be close to (Principal stresses: 300 MPa, 150 MPa, -100 MPa)

Figure for question 80, ISRO Mechanical & Aerospace 2018

  • A. 180 MPa
  • B. 350 MPa
  • C. 255 MPa
  • D. 495 MPa

Answer: B. 350 MPa

Explanation: Using Von Mises theory: (sigma1 - sigma2)^2 + (sigma2 - sigma3)^2 + (sigma3 - sigma1)^2 = 2 * sigma_y^2. Substituting the values gives (-100 - 300)^2 + (300 - 150)^2 + (150 - (-100))^2 = 160000 + 22500 + 62500 = 245000 = 2*sigma_y^2. Thus sigma_y^2 = 122500, making sigma_y = 350 MPa.

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