Springback Prediction Of Roll Forming Of Magnesium Alloy Sheet

In recent years,the research on metal plastic forming has been increasingly thorough with the continuous emergence of new technology and new materials,the requirements of various sheet metal forming were also increasing.Magnesium alloy has the advantages of low density,high specific strength,high specific rigidity,high damping and shock absorption,high thermal conductivity,and easy recycling.Playing an increasingly important role in aerospace,automobile manufacturing,equipment manufacturing and other fields.The obvious tension and compression asymmetry peculiar to magnesium alloys has gradually become a hot issue in the research of magnesium alloy plastic forming technology.In this project,the mechanical properties of AZ31 B magnesium alloy sheet are obtained through uniaxial tensile,uniaxial compression and biaxial tensile tests.The finite element simulation of mechanical property test is carried out,and verify the accuracy of the simulation results.The four parameter method and five parameter method were extended from the stress anisotropy data method and deformation anisotropy data method of hill48 yield criterion.The uniaxial tensile test and uniaxial compression test of AZ31 B magnesium alloy were solved to obtain the anisotropic parameters and verified the convexity,exploring the influence of asymmetry of tension and compression on the Hill48 yield criterion.Design the cyclic loading test,verify its effect on the elongation and elastic modulus of the material.Conduct bending tests and roll forming tests to study the effect of the difference between the true stress-true strain curves of AZ31 B magnesium alloy in tension and compression during bending on spring-back.For the error caused by the asymmetry of tension and compression.Innovatively proposed that the specimen model is divided into two parts in the thickness direction with the neutral layer of the sheet material as the boundary.When assigning material properties,the upper and lower ends of the specimen are respectively given compression and tensile mechanical properties data.Analyze the influence of this method on the simulation spring-back prediction in the bending test.Comparing the bending test and simulation results at different angles,it is found that the spring-back prediction accuracy of the above simulation method is significantly higher than that of the simulation based solely on the uniaxial tensile mechanical properties of the material.The application range of the new simulation method in spring-back prediction is further explored.