Prerequisite: Please read this post first: Time-Temperature Superposition (TTS), TRS, WLF
The test data pictured above, and included in this post was kindly donated by Professor David Jack of Baylor University. In his class on viscoelasticity, his students perform a variety of measurements, including DMA testing. His former student wrote the honors thesis you can find here.
Professor Jack was kind enough to share the raw test data for the PVC material that is shown in the honors thesis (Chapter 4, see for instance, Figure 4.8). This post will step through an Excel spreadsheet in which we:
- Shift the 9 separate pieces of test data (from 9 temperatures) into a Master Curve.
- Show how to use Frequency shift information to derive WLF parameters.
- Show the derivation of Prony parameters to match the Master Curve.
This video will play more clearly if downloaded first. (video file is 98MB, and 20 minutes in duration)
In a separate video, we will continue this story and show:
- Validation of the Prony series / Master Curve using an Abaqus SSD analysis
- Validation of the Prony series / Master Curve using MCalibration (by Veryst Corp.)
- Validation of the entire Hyper+Prony+TRS model using a PSF script
- Validation of the entire Hyper+Prony+TRS model using MCalibration
This video will play more clearly if downloaded first. (video file is 92MB, and 14 minutes in duration)
Other resources:
See Abaqus benchmark Manual article 5.1.7 COUPLED THERMOMECHANICAL ANALYSIS OF VISCOELASTIC DAMPERS
Nice paper with Abaqus material model in the Appendix: https://hal.archives-ouvertes.fr/hal-00867492/document
In the videos we focus on defining these parts:
*Elastic or *Hyperelastic
*Viscoelastic (Prony series)
*TRS
The "other resources" papers show that you will probably also want to specify the density, thermal expansion coefficient, conductivity, specific heat, and inelastic heat fraction.
The attached .zip file contains these three files:
PVC_Hyper_Prony_TRS_Final.xlsx This is the Excel file shown in the videos
Visco_Harmonic.inp This is the template unit-cube model used for validation (driven by .psf python file)
Run_All_Harmonics.psf This .psf file runs the 9 temps x 19 Frequencies = 171 analysis runs
Back to: Material Modeling and Calibration - An Overview and Curriculum
