A Research On Fatigue Behaviour Of Polymethyl Methacrylate

Polymethyl Methacrylate(PMMA) has been widely used in the wind shield of aircraft because of its excellent transparency and strength. The fatigue behaviour of PMMA is very important for the aircraft windshield structure. The commonly used creep models, relaxation models and the relationships between creep and relaxation of PMMA are reviewed in the present thesis. The prediction approaches of fatigue life of PMMA structures are discussed. A simple test device for creep experiment was designed. Axial creep experiment and fatigue experiment of YB-3 PMMA had been carried out. Based on continuum damage mechanics, a modified model to describe the creep damage of YB-3 is developed. Creep experiment data proved that this model can explain creep behavior better and predict creep fracture time of YB-3 more accurately. A creep and fatigue damage model has been presented to explain fatigue test results. There is excellent consistency between the predicted and experiment data.