一种计及分层效应的复合材料层合板疲劳寿命计算方法

A New Method to Predict Fatigue Life of Composite Laminate with Delaminating Effect Considered

给出了一种求解多向铺层复合材料层合板自由边层间应力的简化方法,并在此基础上提出了计及分层损伤的多向铺层复合材料层合板疲劳寿命的计算方法;算例与试验结果对比表明,该方法可以提高复合材料层合板疲劳寿命计算值与试验值的吻合程度。

The classic Tsai-Hill method did not consider delaminating effect; as a result, when delaminating effect can not be ignored, the deviation of its caculated fatigue life from test data becomes very large. We propose a new method, which takes delaminating effect into consideration, that can make the deviation of calculation life from test data much smaller. In the full paper, we explain our new method in much detail; here we give only a briefing. This edge delamination failure mode is caused by the high interlaminar stress concentrated near the free edges. In this paper, we present a simplified method for calculating the interlaminar stress near the free edge of composite laminate. Then the formula to calculate fatigue life of composite laminate is proposed. Finally we give a numeral example of a 16-layer laminate plate [-45/0/45/90/-45/0/45/0]xym. The loading tensile stress cyclically varied from 10% to 100%. When the maximum （100%） loading stress was 711,620, or 566 MPa respectively, we obtain the following results： the test fatigue life was 2 127, 27 612, or 91 327 cycles respectively; the life calculated by the classic Tsai-Hill method was 96 046, 358 543, or 1.29 × 10^6 cycles respectively; the life calculated by our new method was 17 955, 57 450, or 131 318 cycles respectively. These results show preliminarily that our new method can give calculated lives much closer to test fatigue lives.