Principal Stress – Lesson 3

In the previous lesson, we saw how the stress developed in a body is represented in the form of a second-order tensor. We have used a simple cube to illustrate how the stresses act on a small element inside a body. But we haven't talked about whether the orientation of such a cube affects the stresses acting on it.

Why is this important? If you inspect the fracture surface of any broken object, you get an idea about the direction in which the object began to fail. So, it's important to learn where the object experiences maximum stresses to realize how the failure occurs.

Understanding the concept of principal stresses is key here, so it’s the focus of this lesson.

Lecture

Alternate video link.

Handout

Here are the accompanying handout slides for this lesson.