The strength and toughness of components made of polyamide is humidity dependent. Additionally, humidity changes cause dimensional changes and warping. So, a good understanding of a component’s water content is sometimes necessary.
In our laboratory we condition and test polyamide specimens. Accordingly, we created a FE model, which takes thickness, temperature and transient water content into account. By solving the diffusion equation, the transient (time dependent) water content of each point through the thickness was computed. Then the volume-weighted mean water content was derived. This value was directly compared to measured changes of specimen weight.
Test and FE model together serve some purposes:
- material model parameter calibration (swelling)
- model validation
- for developing and checking conditioning guidelines