materialtest

This command category can be used to test most material models depend on strain input only without establishing a FE model. Some wrappers and material models that rely on other material models cannot be tested in this way.

Syntax

materialTest1D (1) (2) (3) [4...]
# (1) int, unique tag of the material model to use
# (2) double, size of per strain increment
# (3) int, number of steps along increment direction
# [4...] int, optional numbers of steps for strain history

materialTest2D (1) (2...4) (5) [6...]
# (1) int, unique tag of the material model to use
# (2...4) double, size of per strain increment
# (5) int, number of steps along increment direction
# [6...] int, optional numbers of steps for strain history

materialTest3D (1) (2...7) (8) [9...]
# (1) int, unique tag of the material model to use
# (2...7) double, size of per strain increment
# (8) int, number of steps along increment direction
# [9...] int, optional numbers of steps for strain history

Remarks

1. The increment size could be either positive or negative.
2. The loading direction reverses after given numbers of steps.
3. The strain-stress history would be saved to RESULT.txt. If HDF5 is used, the result would be additionally saved to RESULT.h5. Besides, a gnuplot file named RESULT.plt will be generated.

Usage

To use the tester, it is necessary to define a material beforehand. Here a Bilinear1D model is defined with elastic modulus $E=1000.0$, yield stress ${\sigma }_y=10.0$ and a negative hardening ratio $h=-0.2$.

material Bilinear1D 1 1000.0 10.0 -0.2

The following command loads towards positive strain direction for 300 increments with increment size of $0.0001$ then negative direction for another 300 increments and eventually 200 increments towards positive direction. The ending strain would be $\epsilon =0.02$.

materialTest1D 1 0.0001 300 300 200

The output is shown as follows.