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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。
In order to establish the long-term stiffness model of FRP pipe and predict the long-term stiffness of FRP pipe. Firstly, the long-term stiffness test of purely circularly wound and purely cross-wound ply fiberglass pipes was carried out under constant displacement with different initial deflection through a self-designed constant displacement load test device. After that, The linear regression model of the stiffness and time of the FRP under the initial deflection and the linear regression model of the stiffness decrease and the initial deflection after 50 years, and then proposed the quadric surface prediction model of the FRP stiffness reduction with time and initial deflection. Finally, The residual stiffness of FRP pipe after 50 years is predicted. The influence of time and initial deflection on FRP pipe stiffness is studied. The results show that the pure circularly wound glass fiber reinforced plastic (FRP) pipe has much better resistance to stiffness attenuation than the purely cross-wound glass fiber reinforced plastic pipe. The pure toroidal winding can effectively increase the FRP pipe stiffness and resistance to radial deformation , Pure ring wrapped fiberglass pipe has better long-term mechanical properties. The time of 8 313.2h test data show that the proposed FRP pipe stiffness drop prediction model with high accuracy and strong practicality.