Abstract An experimental and computational investigation was conducted to evaluate the underwater blast response of fully submerged carbon fiber composite plates after prolonged exposure to saline water. The material was a biaxial carbon fiber/epoxy composite with a [±45°] fiber orientation layup. The plates were placed in a saline water bath with a temperature of 65 °C for 35 and 70 days, which simulates approximately 10 and 20 years of operating conditions in accordance to Fick's law of diffusion coupled with Arrhenius's Equation and a reference ocean temperature of 17 °C. Underwater blast experiments were performed in a 2.1 m diameter pressure vessel. The composite plates were placed in the center of the vessel while fully submerged in water, and an RP-85 explosive was detonated at a standoff distance of 102 mm from the center of the plate. Two cases of fluid hydrostatic gage pressures were investigated: 0 MPa, and 3.45 MPa. Two high speed cameras were utilized for three-dimensional Digital Image Correlation, which provided full-field displacements and velocities of the composite plates during underwater blast loading. A third high speed camera captured the behavior of the explosive gas bubble. Moreover, the pressure fields generated by the explosive detonation and resulting gas bubble were recorded with tourmaline pressure transducers. A water diffusion study was completed which showed that the diffusion of water into the composites reached a point of complete saturation after 35 days of exposure. Quasi-static material characterization tests were performed before and after prolonged exposure to saline water. The properties obtained from quasi-static testing also served as material inputs for the numerical models. The quasi-static test results showed that the tensile modulus E1,2 does not change with exposure to saline water, whereas the in-plane shear modulus G12 decreases with saline water exposure. During blast loading, for the case of 0 MPa hydrostatic gage pressure, the gas bubble interacts with the composite plate substantially. In such an event, the out of plane displacement increased for saline water exposed plates when compared to virgin structures. For the case of 3.45 MPa hydrostatic gage pressure, the gas bubble does not visibly interact with the composite plate. In this case, the out of plane displacement for specimens exposed to saline water was similar to the virgin specimen. A fully coupled Eulerian–Lagrangian fluid structure interaction simulation was performed by using the DYSMAS code. The numerical simulations showed that the displacement of fully submerged composite plates is driven by the displacement of fluid, as well as the size of the gas bubble formed by the explosive rather than the peak pressure generated by the explosive. The numerical simulations were in agreement with the experimental findings in terms of pressure history and plate deformation.

中文翻译：

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水热降解碳纤维/环氧树脂板在完全淹没的环境中承受水下爆炸载荷

摘要 进行了实验和计算研究，以评估长时间暴露在盐水中后完全浸没的碳纤维复合板的水下爆炸响应。该材料是具有 [±45°] 纤维取向叠层的双轴碳纤维/环氧树脂复合材料。将板置于温度为 65 °C 的盐水浴中 35 天和 70 天，根据菲克扩散定律和阿伦尼乌斯方程以及参考海洋温度 17 度模拟大约 10 年和 20 年的操作条件。 ℃。水下爆破实验在直径为 2.1 m 的压力容器中进行。将复合板放置在容器的中心，同时完全浸入水中，RP-85 炸药在距板中心 102 毫米的距离处引爆。研究了两种流体静压表压：0 MPa 和 3.45 MPa。两台高速摄像机用于三维数字图像相关，在水下爆炸加载过程中提供复合板的全场位移和速度。第三台高速摄像机捕捉到爆炸性气泡的行为。此外，用电气石压力传感器记录了由爆炸爆炸和由此产生的气泡产生的压力场。已完成的水扩散研究表明，在暴露 35 天后，水扩散到复合材料中达到了完全饱和的点。在长时间暴露于盐水之前和之后进行准静态材料表征测试。从准静态测试中获得的属性也用作数值模型的材料输入。准静态测试结果表明，拉伸模量 E1,2 不随盐水暴露而变化，而面内剪切模量 G12 随盐水暴露而降低。在爆破加载过程中，对于 0 MPa 静水表压，气泡与复合板有明显的相互作用。在这种情况下，与原始结构相比，盐水暴露板的平面外位移增加。对于 3.45 MPa 静水表压，气泡与复合板没有明显的相互作用。在这种情况下，暴露于盐水的样本的平面外位移与原始样本相似。使用 DYSMAS 代码执行完全耦合的欧拉-拉格朗日流体结构相互作用模拟。数值模拟表明，完全浸没复合板的位移是由流体的位移以及炸药形成的气泡的大小而不是炸药产生的峰值压力驱动的。在压力历史和板变形方面，数值模拟与实验结果一致。数值模拟表明，完全浸没复合板的位移是由流体的位移以及炸药形成的气泡的大小而不是炸药产生的峰值压力驱动的。在压力历史和板变形方面，数值模拟与实验结果一致。数值模拟表明，完全浸没复合板的位移是由流体的位移以及炸药形成的气泡大小而不是炸药产生的峰值压力驱动的。在压力历史和板变形方面，数值模拟与实验结果一致。