考虑夏季-光伏作用高温的经编织物膜材中心撕裂力学行为

Central tearing mechanical behavior of warp-knitted fabric materials considering high temperature of summer-photovoltaic effect

  • 摘要: 在太阳辐射和光伏组件传热形成的高温环境下,光伏膜结构的膜材易在外荷载作用下发生缺陷扩展并引发撕裂破坏。为揭示其高温撕裂机理,对PVDF涂层经编织物膜材进行了高温单轴中心撕裂试验,并利用数字图像相关技术分析了温度与偏轴角度对撕裂力学行为的影响。结果表明,PVDF膜材的撕裂过程及荷载-位移曲线可分为四个典型阶段,切缝尖端存在显著应变集中区。高温会削弱涂层与纤维之间的相互作用,并显著降低材料刚度,其中在100℃时的弹性刚度较25℃降低72.1%,失效模式由“缓性”转变为“剧烈”。偏轴角度对撕裂响应影响显著,临界撕裂抗力随偏轴角度呈“W”型变化,在45°时达到最大值,在约30°和60°降至最小值,仅为峰值的约30%,而峰值位移呈倒“V”型变化。本研究揭示了高温条件下织物膜的撕裂特征,为光伏膜结构系统的安全性评估提供了参考。

     

    Abstract: Under the high-temperature environment caused by solar radiation and heat transfer from photovoltaic components, the membrane material in photovoltaic membrane structures tends to experience defect propagation and tearing failure under external loads. To elucidate the tearing mechanism at elevated temperatures, high-temperature uniaxial central tearing tests were performed on PVDF-coated warp-knitted fabric materials. The effects of temperature and off-axis angle on the tearing behavior were analyzed using digital image correlation (DIC) techniques. Results indicate that the tearing process and the load-displacement response of the PVDF material can be divided into four distinct stages, with a pronounced strain concentration observed at the notch tip. High temperatures weaken the interaction between the coating and fibers, leading to a significant reduction in material stiffness. Specifically, at 100℃, the elastic stiffness decreases by 72.1% compared with that at 25℃, and the failure mode transitions from “gradual” to “abrupt”. The off-axis angle significantly affects the tearing response, with the critical tearing resistance exhibiting a “W-shaped” variation, peaking at 45° and decreasing to approximately 30% of the maximum value near 30° and 60°. The peak displacement displays an inverted “V-shaped” trend. This study elucidates the tearing characteristics of fabric membranes under high-temperature conditions, providing valuable insights for the safety assessment of photovoltaic membrane systems.

     

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