TP008

Test program for modeling the large strain, viscoplastic response of a thermoplastic material at high strain rates (up to ~ 1000-5000/s), with temperature dependence

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 over a range of temperatures and subject to high strain rates (~ 1000-5000/s).

Test Program 
We recommend the following base tests: 

Test ID
 
Description
 
# Temps
 
# Rates per Temp (min) # Repeats
 
# Specimens
 
UT001 Tensile test 3 1 2 6
UC004 Compression testing: load/hold/unload cycles 2 3 2 12
HRC001 High strain rate, Split Hopkinson Pressure Bar (SHPB) compression testing (up to ~1000-5000/s) - room temperature 1 2 3 6

Depending on the material, we may also recommend the following additional tests:

Test ID Description # Repeats # Specimens
VC001 Volumetric compression test 2 2

Notes: 

  • High strain rate testing only available at room temperature.  The temperature-dependent behavior is adequately captured using low strain rate data.
  • Slow strain rate tests are performed for at least three temperatures spanning the range of interest (Room temperature (RT), High Temperature (HT) or Cryogenic Temperature (CT)).  If the temperature range is sufficiently large, more temperatures may be recommended.
  • VC001 is not needed for an incompressible material.
  • Highest strain rate achievable depends on the material and available specimen geometries.  Contact Veryst for more info.
  • 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

  • 8 tensile (dog-bone) specimens
  • 15 compression cylinder specimens
  • 8 Split Hopkinson Pressure Bar compression 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 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 (TP008), type of material, test temperatures, specimen geometries available, or other relevant details.

How can we help?