|Coordinator||CHALMERS TEKNISKA HÖGSKOLA AKTIEBOLAG - Institutionen för industri och materialvetenskap|
|Funding from Vinnova||SEK 522 000|
|Project duration||November 2017 - March 2019|
|Venture||Traffic safety and automated vehicles -FFI|
|End-of-project report||2017-03049sv.pdf(pdf, 960 kB) (In Swedish)|
Purpose and goal
The primary target of the current project was to develop a material model for the PVB-interlayer, which connects the two glass layers to a laminate. It is of utmost importance that the properties of the PVB-material can be modelled with high accuracy. The most pronounced property of the PVB-material is its high strain-rate dependency. The current PVB-model is based on a numerical description of the material properties, and the stress states are obtained by interpolation in tables relating stress, strain, and strain-rate.
Expected results and effects
The developed material model has been shown to be able to correctly simulate the tension tests, which results it is based on. It has also been shown to accurately simulate bi-axial tension tests at different strain rates. Unfortunately, it has been shown that the model gives rise to numerical instabilities in certain examples. At present we do not have a model that can fulfill all demands concerning numerical robustness. Currently, we are working with a substantially revised version of the model. It is our intention to further evaluate this model after the project officially has finished.
Planned approach and implementation
The theory, on which the PVB-model is based, has been deveoped at Chalmers. The different versions of the model have been tested in applications to various testexamples and to real windshields at Chalmers and Volvo Cars. The original intention was that Dynamore Nordic should implement the model as a standard model in the FE-program LS-DYNA, provided that the developed model could fulfill all requirements regarding accuracy and robustness. Since these requirements are not fully fulfilled, this part of the project has been cancelled.