I am currently working on modelling water droplet and solid impact on different types of polyurethane coatings. Here we reach quite high strain rates, as the impact speed is in the range of 100-170 m/s, and we expect the strain rate and amplitude dependence to be significant. Using DMA master curve data, we have had some success in fitting a prony series that can be input in Abaqus, however it only works for some of the materials and is quite simplified.
We have tensile curves at different strain rates and max strain, however i believe such curves do not go near the strain rates we reach in the actual impacts. We also have DMA data both as temperature and frequency sweeps along with master curves, however here we do not reach the high strain rates we see in the experiments. I have tried to use MCalibration to fit different material models to the data but without much success – even when waiting more than a full day for the optimization to run. I am starting to think that we might be taking the wrong approach here, and would be grateful for some advice.
Do you have a suggestion on what kind of experiments makes most sense to use for fitting a material model for the above described problem? We are planning on trying to do cyclic tests similar to those mentioned as “smart testing” in some of the tutorials here on PolymerFEM. As for material model, I have been closest with the TNV model although I could not get a very nice fit, but what kind of material model would you suggest?
Thank you in advance,
Kristine Munk Jespersen