… for extension

The constitutive relation for extension is based on the force on a infinitesimal small part of the cross and Hooke’s law, leading to:

\[N = EA \epsilon\]

This is treated in chapter 2.2.2 of the book Engineering Mechanics Volume 2 (Hartsuijker and Welleman, 2007).

Instructions from lecture

This topic is presented in a lecture available from 0:09:00 - 0:12:30 here for TU Delft students