A Study on Predicting the Long-term Creep Behavior of Plastics using the Short-term Creep Test

Abstract: The creep performance of plastics is one of the main criteria for a variety of applications with strict dimensional stability needs, including electrical/electronic parts and various automotive applications. However obtaining or generating accurate creep data is very difficult for both resin suppliers and product designers because the creep property is time dependent, which means it takes over several weeks or even a year time span. Hence a faster and more reliable method of predicting creep behavior of plastics is required when designing plastic products that will encounter long-term loading. This work presents an easy method for predicting the long-term creep behavior of plastics using the short-term creep experimental data. The flexural creep experiments of three plastics, ABS (Acrylonitrile butadiene styrene), PC/ABS (PC and ABS alloy) and LFT (Long fiber reinforced thermoplastics), are performed. For quick and reliable prediction of long-term creep behavior of plastics, time regional power-law model and time-stress modulus are introduced. To analyze the reliability and validity of the proposed method, the creep analyses based on the proposed method are performed. The comparison between the FEA results and the creep tests has shown that the new method can track both primary and secondary creep behavior over a long time. The creep analyses have been carried out by commercial FE Code.