# Continuum Damage Mechanics (2D Notched Beam)

**URL:** <https://community.freefem.org/t/continuum-damage-mechanics-2d-notched-beam/425>\
**Category:** General Discussion\
**Created:** [May 21, 2020, 8:30pm UTC](https://community.freefem.org/t/continuum-damage-mechanics-2d-notched-beam/425 "2020-05-21T20:30:23Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![geoyanzhan3](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/geoyanzhan3/32/147_2.png) [@geoyanzhan3](https://community.freefem.org/u/geoyanzhan3)\
**Post date:** [May 21, 2020, 8:30pm UTC](https://community.freefem.org/t/continuum-damage-mechanics-2d-notched-beam/425/1 "2020-05-21T20:30:23Z")

</div>

Hi,

Does anyone, by chance, know how to implement FEA for the continuum damage mechanics?

I have questions on how to use the Newton-Raphson method to calculate the damage propagation.

Currently, I am building a 2D Notched Beam model (attached). I am using a straightforward secant stiffness to calculate the stress evolution, which gives me a very wrong solution. I know I need to use tangential stiffness. I don’t know the detailed algorithm.

Thank you very much if you have any clue! It will also be helpful to provide me some literature with detailed implements, examples, and codes. I am attaching my code and the description of the 2D notch beam problem for COMSOL, which I want to benchmark the code with.

Thank you,  
Yan

[NotchedBeam\_2d\_CB.edp](https://community.freefem.org/uploads/short-url/qol9fxTHi687nlW5V2dYjSvBr8e.edp) (5.0 KB) [models.nsm.notched\_beam\_damage.pdf](https://community.freefem.org/uploads/short-url/n0nRVY03cHV1UUkNqkE4RulgoGa.pdf) (1.4 MB)