Research And Exploration On The Fracture Criterion Of Sheet Metal Based On Laser Shock Forming

Laser shock forming(LSF) is a novel forming technique which makes sheet metal deform by laser-induced shock wave.People want to introduce this technology to the practical use as soon as possible when it was invented,but there are many problems needed to solve,such as the sheet metal’s fracture prediction,which hinder the practical use of LSF. So this paper researched on the fracture criterion of sheet metal forming based on LSF, hoping to solve the fracture problem on the forming process of LSF,provide the reference for predicting the formability of sheet metal and ensure the forming quality,and aslo offers the basis for parameter optimization based on LSF in the future.In this paper,the main contents and results are as following:1.Researched on the theory analysis of LSF.Based on the preliminary study on LSF both at home and abroad,this paper researched on the theory analysis of LSF,discussed the mechanical effect of laser shock power and it’s effection to the sheet metal forming behavior, analyzed its fracture mechanism,discussed the thickness thinning of sheet metal based on LSF,pointed out that the phenomenon of thinning out is the significantly manifestations of localized instability.2.Established the thickness reduction criterion based on LSF.Modified the thickness reduction criterion,determined the modified parameter by the fracture test of LSF,got the thickness reduction ratio based on LSF.Took the numerical simulation,and its result was in good agreement with the test,the fracture criterion is basically suitable for LSF.3.The application of this fracture criterion.Choose three typical size of sheet metal, apply this fracture criterion to the simulation to research on the effect of sheet metal size to the formability based on LSF,it can be obtained that the thickness reduction limit and forming depth limit is different when the sheet metal size is changed.