复合材料拉伸剩余强度及其分布

复合材料剩余强度是强度退化疲劳寿命预测模型的基础，本文研究了连续纤维树脂基复合材料（ＦＲＰ）的剩余强度随疲劳载荷加载次数退化的规律，按照ＦＲＰ疲劳损伤的产生和发展的规律，提出了一个ＦＲＰ剩余强度退化的模型，并得到了大量的实验结果的支持。在此基础上提出了一个复合材料剩余强度退化的统计模型：在寿命的初始，剩余强度即为静强度，服从Ｗｅｉｂｕｌ分布；在寿命结束时，即为疲劳强度，服从Ｗｅｉｂｕｌ分布；在不同时刻剩余强度也服从Ｗｅｉｂｕｌ分布，且其方差随加载次数线性变化

A Model of Tensile Residual Strength of FRP and Its Distribution

The residual strength is the basis of the strength based wearout models for predicting the fatigue life of composite structures subjected to fatigue loading. It is known that the residual strength is a monotonically decreasing function of the number of loading cycles, and the loss of the strength follows the damage development. In this paper, the degradation rule of fibre reinforced plastics (FRP) is studied based on the development of the damage in the FRP under cyclic loading and a model to describe the degradation of tensile residual strength of FRP is presented. Large amounts of experimental data have been employed to support this model and the comparison between prediction and experiment demonstrates that this model has better capacity of predicting the degradation of tensile residual strength. On the basis of this model, the statistical model of tensile residual strength of FRP is developed, in which the distribution of the residual strength is presumed to follow Weibull function, whose deviation changes linearly from the one of ultimate strength to that of fatigue strength.