中文摘要：

为建立玻璃钢管长期刚度理论模型并对其长期刚度进行预测。首先通过自主设计的恒位移加载试验装置,在不同初始挠度的恒位移条件下对纯环向缠绕和纯交叉缠绕铺层的玻璃钢管开展了长期刚度试验研究;然后,在试验基础上建立了不同初始挠度下玻璃钢管刚度与时间的折线双对数回归模型、50年后刚度降幅与初始挠度的线性回归模型,进而提出了玻璃钢管刚度降幅关于时间与初始挠度的二次曲面预测模型;最后,预测了玻璃钢管50年后的剩余刚度,研究了时间和初始挠度对玻璃钢管刚度的影响。结果表明：纯环向缠绕铺层的玻璃钢管抵抗刚度衰减的能力明显优于纯交叉缠绕铺层的玻璃钢管,纯环向缠绕铺层能有效提高玻璃钢管的刚度及其抵抗径向变形的能力,纯环向缠绕铺层的玻璃钢管有较好的长期力学性能。时间为8 313.2h的测试数据表明提出的玻璃钢管刚度降幅预测模型具有较高的精度和较强的实用性。

英文摘要：

In order to establish the theoretical model for long-term stiffness of fiber reinforced plastic pipes,and predict the long-term stiffness of them,using the autonomous designed constant displacement loading test apparatus,the testing investigations for long-term stiffness of glass fiber reinforced plastic pipes with of pure hoop winding and pure cross winding plies were performed under constant displacement conditions of different initial deflections firstly.Then,stiffness vs time broken line log-log regression model of glass fiber reinforced plastic pipes under different initial deflections,linear regression model of stiffness degradation rate after 50 years vs initial deflection were established based on the test,thus quadratic surfaces prediction model of glass fiber reinforced plastic pipes stiffness degradation rate vs time and initial deflection was proposed.Finally,the residual stiffness of glass fiber reinforced plastic pipes after 50 years was predicted,and the effects of time and initial deflection on stiffness of glass fiber reinforced plastic pipes were investigated.The results show that the ability to resist stiffness degradation of glass fiber reinforced plastic pipes with pure hoop winding ply are much more superior to that of glass fiber reinforced plastic pipes with pure cross winding ply,pure hoop winding ply can improve the stiffness of glass fiber reinforced plastic pipes and the ability to resist radial deformation of them effectively,glass fiber reinforced plastic pipes with pure hoop winding ply have better long-term mechanical performances.The test data when the time is 8 313.2hindicates that the proposed prediction model for stiffness degradation rate of glass fiber reinforced plastic pipes has relatively high precision and relatively great applicability.