BOND STRENGTH DEGRADATION OF ADHESIVE- BONDED CFRP COMPOSITE LAP JOINTS AFTER LIGHTNING STRIKE
BOND STRENGTH DEGRADATION OF ADHESIVE- BONDED CFRP COMPOSITE LAP JOINTS AFTER LIGHTNING STRIKE
复制标题
雷击后粘合剂粘合 CFRP 复合材料搭接接头的粘合强度下降
DOI：
10.12783/asc36/35742
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发表时间：
2021
期刊：
影响因子：
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通讯作者：
B. Davidson
中科院分区：
文献类型：
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作者：
Wenhua Lin;Yeqing Wang;Spencer Lampkin;Srihari Prasad;O. Zhupanska;B. Davidson
粘接连接纤维增强聚合物基复合材料有望取代传统的机械连接技术来连接复合材料部件。了解这些粘接接头在受到各种环境载荷(如雷击)时的行为，是粘接复合材料飞机和航天器结构安全设计中的一个重要问题。为了评价雷击对单层搭接接头力学行为的影响，在四种放电冲击电流水平(71.4kA、100.2 kA、141kA和217.8 kA)下进行了模拟雷击试验。在记录了目测到的雷击损伤后，进行了单搭接剪切试验，以确定剩余粘结强度。通过试验后的目视观察和横断面显微镜观察来记录粘结剂区域的破坏模式。虽然目前的工作是在有限数量的样品上进行的，但它为未来更全面地研究粘接复合材料的雷击效应确定了重要的趋势和方向。结果表明，雷击损伤(表面汽化面积和分层深度)随雷击电流的增大而增大。粘接接头的硬度和剪切粘接强度与雷电电流水平没有显示出明显的相关性，这可能是由于许多竞争因素，包括雷击造成的温升和粘接前粘结物的表面状况。所有试件粘结区的破坏模式都表现为粘结破坏和粘结破坏的混合模式，这可能是由于粘接前粘结体的表面特征不一致所致。在搭接剪切试验中吸收的能量通常随着雷电电流的增加而增加。
Adhesive bonding to join fiber reinforced polymer matrix composites holds great promise to replace conventional mechanical attachment techniques for joining composite components. Understanding the behavior of these adhesive joints when subjected to various environmental loads, such as lightning strike, represents an important concern in the safe design of adhesively bonded composite aircraft and spacecraft structures. In the current work, simulated lightning strike tests are performed at four elevated discharge impulse current levels (71.4, 100.2, 141, and 217.8 kA) to evaluate the effects of lightning strike on the mechanical behavior of single lap joints. After documentation of the visually observed lightning strike induced damage, single lap shear tests are conducted to determine the residual bond strength. Post-test visual observation and cross-sectional microscopy are conducted to document the failure modes of the adhesive region. Although the current work was performed on a limited number of specimens, it identified important trends and directions for future more comprehensive studies on lightning strike effects in adhesively bonded composites. It is found that the lightning strike induced damage (extent of the surface vaporization area and the delamination depth) increases as the lightning current increases. The stiffness of the adhesive joints and shear bond strength did not show a clear correlation with the lightning current levels, which could be due to many competing factors, including the temperature rise caused by the lightning strike and the surface conditions of the adherends prior to bonding. The failure modes of the adhesive regions for all specimens demonstrate a mixed mode of adhesive and cohesive failure, which may be due to inconsistent surface characteristics of the adherends before bonding. The energy absorbed during the lap shear tests generally increases as the lightning current increases.