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针对单道多层的直薄件激光立体成形过程,建立了基板预变形和无预变形条件下的3D参数化有限元模型,进行了应力和变形的瞬时热弹塑性有限元模拟分析。模拟结果表明,基板预变形处理影响成形件应力和变形的分布与大小,并可减轻基板的翘曲变形。预变形下基板下表面具有初始拉应力点的残余应力值比无预变形要小,基板与熔覆层接触的界面中间位置残余应力也小于无预变形的情况,直薄壁件最大残余压应力所在位置也发生变化。在两模型中,熔覆层两侧边缘位置变形严重,而中间位置变形较小。熔覆层首层的沉积对基板变形量影响最大,后续熔覆层的沉积对基板变形量影响程度逐渐减小并最终趋于稳定。成形前对基板进行适当的预变形处理可以有效控制成形件变形和改善应力分布。
A 3D parametric finite element model with pre-deformation and pre-deformation of substrate was established for single-layer and multi-layer thin laser processing. The transient thermal elasto-plastic finite element simulation of stress and deformation was carried out. The simulation results show that the pre-deformation of the substrate affects the distribution and size of the stress and deformation of the formed part, and can reduce the warpage of the substrate. Under the pre-deformation, the residual stress of the lower surface of the substrate with the initial tensile stress is smaller than that without pre-deformation, the residual stress at the interface between the substrate and the cladding is smaller than that without pre-deformation, and the maximum residual compressive stress The location is also changing. In the two models, the positions of the edges on both sides of the cladding layer deform seriously, but the deformation in the middle position is smaller. The deposition of the first cladding layer has the greatest influence on the deformation of the substrate, and the influence of subsequent cladding layer deposition on the deformation of the substrate decreases gradually and eventually stabilizes. Pre-deformation of the substrate before the appropriate pre-deformation treatment can effectively control the deformation and improve the stress distribution.