Mechanics of Materials

Lesson 34

Stress Transformation I

Learning outcomes

    1. Cut FBDs through inclined planes and place them in static equilibrium.
    2. Correctly identify and name all of the nine 3D stresses using correct symbols, correct subscripts, and correct sign conventions.
    3. Explain what is meant by “plane stress.”
    4. Understand that all stress transformations are conducted one rotation at a time, about x, about y, or about z.
    5. Understand the definition and sign convention for theta: the angular measurement from an input (native) coordinate system to an output (desired) coordinate system.
    6. Apply the stress transformation equations to transform (plane) stresses from one coordinate system to another.
    7. Properly interpret the results of the stress transformation equations and illustrate the transformed state of stress on a properly oriented stress element (include: x-axis, x’-axis, y’-axis, angular rotation, stress element in the rotated geometry, and all applicable stresses in the proper direction and with the proper units).

In-Class Notes

LE34 Stress Transformation I.pdf


HW34 Stress Transformation I.pdf