Impact analysis

Features

Impact analysis is a CAE technology that predicts the response of an object, such as stress and displacement, in phenomena such as collisions and drops where sudden force is applied to the object in a short period of time.

Strain rate dependence of resins.

Plastics have the property of becoming harder as the deformation speed increases.
This is called strain rate dependence.

If the phenomenon you want to predict becomes faster, you cannot express only by the normal resin characteristics (low-speed stress-strain curve).

Tester for impact velocity and physical property measurement

stress-strain curve

Asahi Kasei’s unique material model

Crystalline resin represented by polyamide has a crystalline part and an amorphous part as shown in the figure.

When a non-reinforced dumbbell-shaped specimen of polyamide is pulled, then necking occurs in this way, which causes ductile fracturing.

This is because the polymer of the amorphous part is stretched and the resin has the characteristic that the fracture occurs at the boundary between the crystalline part and the amorphous part.

We have developed a material model that considers such microscopic damage and applied it to impact analysis so that we can predict the failure mode and the amount of energy absorbed at the time of failure.

Asahi Kasei 's proprietary material model Microscopic damage model Fig.4 Material model considering the craze effect

Application examples of Asahi Kasei's unique material model

By applying a unique material model, the analysis results are more consistent with actual failure modes compared to conventional material models.

Our unique model matches the failure modes of analysis results and experimental results

Application example for oil pan chipping evaluation

We compared a simulation of a test in which a metal bullet that simulates a bouncing stone collides with a resin oil pan, and the actual test shot with a high-speed camera. The analytical results and experimental results are in good agreement, and the results obtained are suitable for complex shapes other than test specimens.

For details, please refer to CAE Case Studies "Accuracy validation of impact analysis ".

Oil pan chipping evaluation analysis results Simulation result