Off-the-shelf Simulation for Demoldable Mandrels: An Experimental and Numerical Approach to Thermoplastic Shape-Memory Polymers

Kurzfassung

The production of one-piece composite hollow profiles with undercuts presents significant challenges to conventional mold concepts. Mandrels made of thermoplastic shape-memory polymers could facilitate demolding and reduce tooling costs. To design molds in a commercial environment, it is critical to determine their behavior using off-the-shelf Finite Element Analysis (FEA) software. This study presents a shape-memory test procedure for coupon test specimens under tensile load. Furthermore, the test is used to validate a simulation using a generalized Maxwell model, a linear viscoelastic material model implemented in off-the-shelf commercial FEA software. The materials investigated are PA6 and PET. The simulation shows good results in comparison with the thermo-mechanical shape-memory test. The results are then transferred to blow-molded bottle-shaped mandrels e.g. for the manufacturing of Type V pressure vessels. Test results are compared with the simulation results and deviations are discussed. In conclusion, the straightforward -from material to solution- approach presented allows us to model and simulate the shape memory behavior of linear viscoelastic polymers with off-the-shelf commercial FEA software.