基于非对称双悬臂梁模型优化的双金属板界面结合强度研究

An Investigation of Interface Bonding Strength of Bimetal Plate Based on the Optimization of Asymmetric Double Cantilever Beam Model

基于非对称双悬臂梁模型,在充分考虑金属复合材料界面的塑性变形行为的基础上,提出解析计算双金属板界面结合强度的改进方法,以解决金属界面结合强度高于基材强度时金属复合材料界面结合强度难以获得的难题。借助渐进成形实验验证了该方法的正确性,并获得爆炸复合的T2/A1050 Cu-Al复合板界面结合强度为208 MPa。界面结合强度与最大成形深度相关,当界面结合强度增加38%时,最大成形深度增加了210%。压下量和工具头直径严重影响鼓包高度,当压下量由2.0 mm降低至0.5 mm,鼓包高度降低57%;工具头直径由10 mm升高至22 mm,鼓包高度下降38%。最后,优选了合理的成形参数,使双金属复合板底面鼓包高度下降53%。

The bimetal sheet products obtained by the incremental forming are gradually gaining popularity because of their excellent properties.The forming process of the bimetal sheets is more complicated than that of the single metal sheet because it involves a complex interface between the two metal sheets.The bonding strength of the interface is an important parameter for evaluating the bonding properties of a bimetal sheet.However,if the required bonding strength is higher than the strength of the substrate,appropriate strength is difficult to achieve using only experimental methods.An improved analytical method to calculate the interface bonding strength has been proposed based on the widely used interface model of an asymmetric double cantilever beam.This improved analytical method considers the plasticity of the interface.The interface bonding strength of the explosively welded T2/A1050 copperaluminum bimetal sheet has been assessed using the improved method,and its interface bonding strength has been found to reach 208 MPa.This bonding strength has been used in a finite element model for the forming process of the bimetal sheet.The correctness of the method has been verified by comparing the analytical results with the experimental data.Furthermore,the influence of interface bonding strength on the maximum forming depth has been explored,and it has been found that the maximum forming depth increased by 210%when the interface bonding strength increased by 38%.Moreover,a threedimensional model including a tool,the Cu-Al bimetal sheet,and a cohesive element between the two metal sheets has been suggested for investigating the bulge defect of the forming part.The bonding strength of the interface obtained above has again been utilized in the finite element analysis.The impacts of different reductions and tool diameters on the bulge defect of the forming part have systematically been discussed.The results show that bulge defect decreased by 57%when the reduction decreased from 2.0 mm to 0.5 mm,and the bulge defect decreased by 38%when the tool diameter increased from 10 mm to 22 mm.Optimized parameters have been suggested to effectively reduce the bulge defect by 53%.