# 2D plasticity

## Forward vs backward Euler for return algorithms

In Part 5 of my series on return mapping for plane stress plasticity, I claim that the obsession with backward Euler is not justified if accuracy is important.  See http://www.parresianz.com/mechanics/plasticity/algorithm/plane-stress-drucker-prager-return-part-5/.

Let me know if you disagree and why.

-- Biswajit

## More on plane stress Drucker-Prager plasticity

Parts 3 and 4 of the series on plane stress Drucker-Prager plasticity are now online.  More to come soon.

Check out

http://www.parresianz.com/mechanics/plasticity/algorithm/plane-stress-drucker-prager-return-part-3/

and

## Plane stress Drucker-Prager plasticity (part 2)

Part 2 of plane stress Drucker-Prager return algorithm: http://www.parresianz.com/mechanics/plasticity/algorithm/plane-stress-dr...

-- Biswajit

## Plane stress Drucker-Prager plasticity (part 1)

New blog post:  Plane stress Drucker-Prager plasticity (part 1): http://www.parresianz.com/mechanics/plasticity/algorithm/plane-stress-dr...

-- Biswajit

## How to use non-dimensional form in open source codes instead of Units

Choose a channel featured in the header of iMechanica:

I am using an open source FEM platform, which requires you to convert your equation system to non-dimensional form. So, there are no units specified for the parameters in the problem. If you use compatible input units, you should expect the output in matching unit - just like one would do in a normal python or C++ code for solving physical problems. I have an elasto-plastic dynamic problem to solve, and these are the parameters for the Drucker-Prager Soil Model for soft clay.

E = 5000000;                 // Young's Modulus in N/m^2 or Pa

## How to use non-dimensional form in open source codes instead of Units

I am using an open source FEM platform, which requires you to convert your equation system to non-dimensional form. So, there are no units specified for the parameters in the problem. If you use compatible input units, you should expect the output in matching unit - just like one would do in a normal python or C++ code for solving physical problems. I have an elasto-plastic dynamic problem to solve, and these are the parameters for the Drucker-Prager Soil Model for soft clay.

E = 5000000;                 // Young's Modulus in N/m^2 or Pa