VPF粘性介质粘弹性本构关系研究

Study on viscoelastic constitutive relationship of viscous medium used in viscous pressure forming

为研究粘性介质的力学性能对板材变形的影响,通过剪切蠕变-回复和松弛试验分析了甲基乙烯基粘性介质的流变性能.实验结果表明粘性介质可以简化为线性粘弹性材料.建立了粘性介质的积分型粘弹性本构方程,并结合剪切蠕变-回复过程的有限元分析确定了方程中的材料参数.利用该本构方程对粘性介质压力胀形过程进行了有限元分析,模拟结果与试验结果对比表明,所建立的本构方程可以较好的预测板材的变形过程.

To invesigate the effect of the mechanic properties of viscous mediums on the deformation of sheet metals, shear creep-recovery and relaxation tests were carried out to investigate the rheological property of one kind of viscous medium, methylvinylpolymer. The results show that viscous medium can be simplified as a linear viscoelastic material. An integral viscoelastic model was adopted as the constitutive equation of viscous medium. Parameters in the constitutive equation were determined by the combination of finite element analysis and experimental results of the creep - recovery process. This viscoelastic constitutive equation was then used to simulate the viscous pressure bulging periment demonstrates that the proposed als qualitatively and quantitatively. process. The comparison of the results between the simulation and exconstitutive equation can predict the deformation process of sheet metals qualitatively and quantitatively.