The mechanical characteristics of short-fiber-reinforced thermoplastics should be evaluated based on viscoelastic theory because of the time and temperature dependent characteristics of the matrix resin. In this study, the viscoelastic characteristics of short-fiber-reinforced polybutylene terephthalate, PBT composite, are evaluated by material testing and micromechanics model. Firstly, tensile tests are carried out PBT composite with three fiber volume ratios under various temperature and strain rate conditions. The results show that the viscoelastic characteristics of the PBT composites can be obtained by the time-temperature superposition principle using shift factor of the PBT resin. Next, the Eshelby model combined with the Mori–Tanaka theory is used to predict to the viscoelastic characteristics of the PBT composites based on the measurement of fiber length and fiber orientation angle. The predicted viscoelastic characteristics of the PBT composites are in good agreement with the tensile test.

由于基体树脂的时间和温度相关特性，应基于粘弹性理论评估短纤维增强热塑性塑料的机械特性。在这项研究中，通过材料测试和微力学模型评估了短纤维增强的聚对苯二甲酸丁二醇酯（PBT）复合材料的粘弹性特征。首先，在不同的温度和应变速率条件下，以三种纤维体积比对PBT复合材料进行了拉伸试验。结果表明，利用PBT树脂的位移因子，可以通过时间-温度叠加原理获得PBT复合材料的粘弹性特征。下一个，Eshelby模型结合Mori–Tanaka理论用于基于纤维长度和纤维取向角的测量来预测PBT复合材料的粘弹性特征。PBT复合材料的预测粘弹性特性与拉伸试验非常吻合。