Test program for modeling the large strain, viscoplastic response of a thermoplastic material with moderate rate dependence (up to ~1/s)
Description
This test program is recommended for developing a constitutive model of a thermoplastic material intended to capture the large strain, viscoplastic response of the material at a fixed temperature, including strain rate effects up to moderate strain rates (~1/s).
Test Program
We recommend the following base tests:
| Test ID | Description | # Rates | # Repeats | # Specimens |
|---|---|---|---|---|
| UT001 | Tensile test | 3 | 2 | 6 |
| UT005 | Tensile testing: load/hold/unload cycles | 3 | 2 | 6 |
| UC004 | Compression testing: load/hold/unload cycles | 1 | 2 | 2 |
Depending on the material, we may also recommend the following additional tests:
| Test ID | Description | # Repeats | # Specimens |
|---|---|---|---|
| VC001 | Volumetric compression test | 2 | 2 |
Notes:
- These tests are performed at a fixed temperature [Room Temperature (RT), High Temperature (HT) or Cryogenic Temperature (CT)].
- Strain rates typically span three decades over the range of interest.
- Compression testing in base test program done at one rate comparable to tensile testing to evaluate tension/ compression yield and flow symmetry.
- VC001 is not needed for an incompressible material.
- The test program assumes the material is isotropic. If the material is anisotropic, Veryst recommends a different suite of tests. Contact Veryst for more information.
Specimen Requirements
- 15 tensile (dog-bone) specimens
- 3 compression cylinder specimens
- 3 volumetric compression specimens
See the description of individual tests for details on specimen geometries. Note that we request extra specimens to ensure a sufficient supply of specimens for valid testing.
Veryst can also assist in molding standard and non-standard test specimens. Please contact us if you are interested in discussing this option.
Material Model Calibration
Veryst can use the above test program to calibrate an appropriate elastic-plastic constitutive model for use in finite element simulations. Veryst can calibrate models built-in to commercial finite element (FE) codes (Abaqus, ANSYS, COMSOL Multiphysics, LS-DYNA, etc.) or advanced models from the PolyUMod® library, which may also be used with most commercial FE codes.
Typical candidate material models include advanced polymer viscoplasticity models [Bergstrom-Boyce, three-network model (TNM), parallel network model (PNM), parallel rheological flow (PRF), etc.] The specific model selected depends on the material behavior and your FE software.
Additional Validation
Veryst can perform additional validation, depending on the target material and the simulation application, through any of the following tests and any necessary component level FE simulation:
- Impact testing
- Micro-to-macro indentation responses
More Information
For a customized quotation, please write to us at testing@veryst.com and indicate the Test ID (TP005), type of material, test temperatures, specimen geometries available, or other relevant details.