Zhang Yunlong, Tao Wang, Chen Yanbin, Lei Zhenkun, Bai Ruixiang, Lei Zhenglong
State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China.
State Key Laboratory of Structural Analysis for Industrial Equipment, Dalian University of Technology, Dalian 116024, China.
Materials (Basel). 2020 Aug 14;13(16):3599. doi: 10.3390/ma13163599.
The aim of this work was to study the buckling behavior and failure mode of the double-sided laser-welded Al-Li alloy panel structure under the effect of axial compression via experimental and numerical simulation methods. In the test, multi-frequency fringe projection profilometry was used to monitor the out-of-plane displacement of the laser-welded panel structure during the axial compression load. In addition, the in-plane deformation was precisely monitored via strain gauge and strain rosette. The basic principles of fringe projection profilometry were introduced, and how to use fringe projection profilometry to obtain out-of-plane displacement was also presented. Numerical simulations were performed using the finite element method (FEM) to predict the failure load and buckling modes of the laser-welded panel structure under axial compression, and the obtained results were compared with those of the experiment. It was found that the fringe projection profilometry method for monitoring the buckling deformation of the laser-welded structure was verified to be effective in terms of a measurement accuracy of sub-millimeter level. The structural failure was caused by local buckling of the skin. The observed failure modes such as local buckling of the skin, bending deformation of the stringers, continuous fracture of several welds, and failure of local strength and stiffness were attributed to the deformed laser-welded panel structure under the axial compression. The predicted failure load in the numerical simulation was slightly smaller than that of the experimental test, and the error of the simulation result relative to the test result was -2.7%. The difference between them might be due to the fact that the boundary and loading conditions used in the FEM model could not be completely consistent with those used in the actual experiment.
本工作的目的是通过实验和数值模拟方法研究双面激光焊接铝锂合金板结构在轴向压缩作用下的屈曲行为和失效模式。在试验中，采用多频条纹投影轮廓术监测激光焊接板结构在轴向压缩载荷作用下的面外位移。此外，通过应变片和应变花精确监测面内变形。介绍了条纹投影轮廓术的基本原理，并阐述了如何利用条纹投影轮廓术获取面外位移。采用有限元方法（FEM）进行数值模拟，以预测激光焊接板结构在轴向压缩下的失效载荷和屈曲模式，并将所得结果与实验结果进行比较。结果表明，条纹投影轮廓术用于监测激光焊接结构的屈曲变形，在亚毫米级测量精度方面被验证是有效的。结构失效是由蒙皮的局部屈曲引起的。观察到的失效模式，如蒙皮的局部屈曲、桁条的弯曲变形、多条焊缝的连续断裂以及局部强度和刚度的失效，均归因于激光焊接板结构在轴向压缩下的变形。数值模拟中预测的失效载荷略小于实验测试值，模拟结果相对于测试结果的误差为-2.7%。两者之间的差异可能是由于有限元模型中使用的边界和加载条件与实际实验中使用的条件不完全一致。
