Class Summary – 26 Jan, 2015 – Stress & Strain

We finished stress and strain and I introduced Hooke’s Law and the equations of motion. You should be able to read Chapter 3 of the text now, not all of it is simple, but you have the basic definitions. Understanding all the mathematical details should be your goal, but at least now, so we can move forward, you should understand how the key ideas of stress, strain, Hooke’s Law and Newton’s 2nd Law are combine to produce the equations of motion.

$$\sigma_{ij,j} + f_i = \rho \ddot{u}_{i,t}$$