Invar 36合金厚板三点弯曲回弹规律研究

Study on springback law of thick Invar 36 alloy sheet during three-point bending

采用Ls-Dyna软件,利用Swift硬化模型、Mises屈服准则,建立三点弯曲有限元模型,模拟研究了不同厚度、不同温度下Invar 36合金厚板的回弹规律。依据模拟结果,设计制作三点弯曲模具,在万能液压机上进行三点弯曲回弹试验。结果表明,板料厚度越大,成形温度越高,回弹程度越小。室温下材料厚度从12.7增加至19.05 mm时,回弹量由19.73%降至10.76%,减小了45.5%;19.05 mm厚度的板料成形温度为室温时回弹量为10.76%,而当成形温度升高至800℃时回弹量则降至1.4%,减小了87.0%。有限元模拟结果和试验结果吻合度高,表明该有限元模型、材料模型可有效预测Invar 36合金不同厚度、不同温度下的回弹情况。

Effects of thickness and forming temperature on springback law of thick Invar 36 alloy sheet during three-point bending were studied by finite element simulation which carried out with Ls-Dyna software based on Swift hardening model and Mises yield criterion.According to the simulation results,a three-point bending die was designed to conduct springback experiment on an universal hydraulic machine. The result shows that springback value decreases with the increase of sheet thickness and forming temperature. When sheet thickness increases from 12. 7 to 19. 05 mm at ambient tempreture,springback value decreases from 19. 73% to 10. 76% which decreases by 45. 5%. Furthermore,springback value decreases from 10. 76% to 1. 4%,which decreases by 87. 0% with bending temperature increasing from ambient temperature to 800 ℃. The simulation results agree well with the experiment ones which indicates that finite element model and material model can accurately predict springback behavior of Invar 36 alloy with different thicknesses and forming temperatures.