dmises¶

Purpose:

Form the elasto-plastic continuum matrix for an isotropic hardening von Mises material.

Syntax:

D = dmises(ptype, mp, es, st)

Description:

dmises forms the elasto-plastic continuum matrix for an isotropic hardening von Mises material.

The input variable ptype is used to define the type of analysis, cf. hooke.

The vector mp contains the material constants:

mp = [\(\small{\, E\;\nu\;h\,}\)]

where \(E\) is the modulus of elasticity, \(\nu\) is the Poisson’s ratio, and \(h\) is the plastic modulus.

The matrix es contains current stresses obtained from plants or some similar s-function, and the vector st contains the current state parameters:

st = [\(\small{\, yi\;\sigma_y\;\varepsilon_{eff}^p\,}\)]

where \(yi = 1\) if the material behaviour is elasto-plastic, and \(yi = 0\) if the material behaviour is elastic. The current yield stress is denoted by \(\sigma_y\), and the current effective plastic strain by \(\varepsilon_{eff}^p\).

Note:

Only the case ptype = 2 is implemented.