Question

Select the correct answer to the following multiple-choice questions. Briefly explain your choice.

16. The von Mises stress when displayed in a different coordinate system
    A) will not change,
    B) will change according to the new coordinate system,
    C) will change with the coordinate system, but that change will be in general relatively small.

17. In plane-stress analysis when the stress components are displayed the choice of the coordinate system in which to represent the components will have the following effect:
    A) the components will change according to the coordinate system,
    B) will remain the same,
    C) will only change when displayed as averaged at the nodes,
    D) none of the above.

Answer 1

Ans 16) Option C - Von mises stress is the value used to determine if the material will yield or fracture.The Von Mises vriteria states that if Von Mises stress of material is equal to or greater than yield limit of same material under sumple tension,then material will yield. Since, the material and properties are same and only expressiing method (different coordinate system) is changing, hence their is no significant change in value of Von Mises stress.However, due to different graphical approach , their will be a little difference in final result but it is negligible.

Ans 17) Option A - The components of stress will change according to coordinate system .Only state of stress at a point will remain same with different coordinate system and rest of components will change .A member may experience larger stress on inclined plane than the cross section .Hence, stress component changes with different coordinate system