A Numerical simulation of delamination caused by internal gas pressure for mid-density CFRP
A Numerical simulation of delamination caused by internal gas pressure for mid-density CFRP
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DOI：
10.1016/j.compositesa.2018.10.004
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发表时间：
2018-12-01
影响因子：
8.7
通讯作者：
Kogo, Yasuo
中科院分区：
文献类型：
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作者：
Koyanagi, Jun;Shinba, Kenta;Kogo, Yasuo
层间脱粘（分层）是碳纤维增强塑料（CFRP）在用于受到快速加热的热防护系统（例如在重返大气层的情况下）时的主要问题。在这项研究中，通过控制材料孔隙率来避免分层的可能性进行了实验和数值研究。制备具有各种初始孔隙率的CFRP试样（中密度CFRP），并进行快速加热试验（类似于6 MW/m2），并检查试样以确定是否发生分层。为了预测分层，传热和热解气体引起的内部气体压力增长作为加热时间的函数进行了数值模拟。关于温度依赖性的化学反应速率，正交各向异性系数的气体渗透性，和flatwise拉伸强度的参数进行了测定，通过单独的实验，使用CFRP试样。采用有限差分法，利用实验获得的参数，对遵循达西定律的传热和热解气体流动进行了耦合分析。当气体压力超过CFRP的水平拉伸强度时，假设发生分层。数值计算结果与实验结果吻合较好，表明采用中密度碳纤维复合材料可以有效地消除分层。
Interlaminar debonding (delamination) is a major problem for carbon fiber-reinforced plastic (CFRP) when it is used in thermal protection systems subjected to rapid heating, such as in a re-entry situation. In this study, the possibility of avoiding delamination by controlling material porosity was investigated experimentally and numerically. CFRP specimens having various initial porosities (mid-density CFRP) were prepared and rapid heating tests (similar to 6 MW/m(2)) were performed, and the specimens were examined to determine whether delamination had occurred. To predict the delamination, heat transfer and pyrolysis gas-induced internal gas pressure growth were simulated numerically as a function of heating time. The parameters regarding temperature-dependent chemical reaction rate, orthotropic coefficients for gas permeability, and flatwise tensile strength were determined by individual experiments using the CFRP specimens. The coupled analysis of thermal transfer and pyrolysis gas flow following Darcy's law was conducted by finite-difference form, employing the experimentally obtained parameters. When the gas pressure exceeds the flatwise tensile strength of CFRP, delamination is assumed to occur. The numerical results show good agreement with the experimental results, and it is concluded that delamination can be eliminated by using mid-density CFRP.