穿孔泡沫夹层复合材料低速冲击性能试验研究

针对普通泡沫夹层复合材料层间性能较弱的问题，提出在泡沫上预先打孔的方法，在泡沫芯材中形成胶钉从而提高泡沫夹层材料的力学性能，并对穿孔泡沫夹层复合材料的低速冲击性能进行了研究。通过手糊和真空辅助成形工艺制备穿孔泡沫夹层复合材料试验件，对其进行不同能量的低速冲击试验，记录接触力、冲头位移和能量吸收率等力学响应，并采用目视检测和超声C扫无损检测两种方法确定冲击损伤的范围，探究胶钉密度、打孔深度和泡沫槽宽等变量对穿孔泡沫夹层复合材料低速冲击阻抗性能的影响。试验结果表明，随着冲击能量的增加，最大接触力、最大冲头位移和残余变形均增加，凹坑深度和内部损伤面积也增大，同时结构的能量吸收率也有所提高；适当地增加胶钉密度和泡沫槽宽能提高穿孔泡沫夹层材料的低速冲击阻抗性能，而泡沫孔深度对其冲击性能的影响较小。     

Review on residual stress and its effects on manufacturing of aluminium alloy structural panels with typical multi-processes

In the aerospace industry, integrated aluminium alloy plates and stiffened panels with high accuracy and performance attract significant interest. To manufacture these panels as integrity with high accuracy, multiple processes need to be utilised, such as machining, welding and forming. During the whole manufacturing chain, residual stresses can be generated and redistributed in the components among different processes. The residual stress would significantly affect the shapes and properties of the final products. Currently, these great effects are not well considered in the design and manufacturing processes. This paper aims to draw a general understanding of the residual stress generated in the pre-manufacturing processes and its effects on subsequent manufacturing processes. The mechanisms and distributions of residual stresses generated in typical pre-manufacturing processes of structural panels, including machining, welding and additive manufacturing (AM), are firstly summarised. The detailed effects of generated residual stresses on distortion and application properties in subsequent manufacturing processes are then concluded. In addition, current methods developed for the investigation of residual stress effect in multi-processes manufacturing are critically reviewed, including experimental, analytical, finite element (FE) and machine learning methods. Furthermore, the future development trend of methods for residual stress consideration and control in the design of manufacturing processes is summarised, providing comprehensive guidance to achieve the high accurate manufacturing of aluminium alloy structural components.