Effect of Material Model in PMMA Forming Process; a Case Study

Thermoforming, as a common and simple method offorming polymeric parts, is a deformation process of apolymer in the rubbery state above its glass transitiontemperature. However the contact of the softenedpolymeric sheets with the mould surface at differentstages of thermoforming can affect the final geometryof the component.Poly metal methacrylate (PMMA) is a type ofpolymer with many industrial applications such asmanufacturing airplane canopy bubble which is carriedout at high temperature (۱۳۰ºC). The behavior ofPMMA is highly nonlinear and depends on thetemperature, so simulation of its forming process is auseful solution to verify the effect of relevantparameters using FEM. Process simulation requires anappropriate mechanical behavior for PMMA. In thispaper, different mechanical behaviors of PMMA areused to simulate the canopy bubble forming process.First, four simulations with elastic-plastic model,Mooney-Rivlin, Ogden and polynomial are done byAbaqus/Implicit. Then, two cross sections aredemonstrated in two perpendicular path samplesthrough final shapes. Finally section profiles arecompared with experimental profile and an appropriatemechanical behavior for PMMA in high temperatureforming processes is suggested.

کلیدواژه ها:

PMMA forming ، FEM simulation ، mechanicalbehaviors ، airplane canopy