模外装饰贴膜材料力学性能研究

Study of Mechanical Properties of Films for Outside Mold Decoration

以对聚甲基丙烯酸甲酯(PMMA)为膜外装饰贴膜材料,对其进行不同温度和不同拉伸速度的高温单向拉伸实验,得到相应条件下PMMA的真实应力-真实应变曲线,分别计算出不同温度和不同应变速率的DSGZ本构模型系数,将DSGZ模型的理论预测曲线与其拉伸实验数据曲线进行对比分析。结果表明,在同一温度下,随着应变速率的增大,其真实应力、拉伸比和屈服强度也相应地增大;在同一应变速率下,随着温度的逐渐升高,PMMA的应变软化和屈服现象随之减弱直至消失,其真实应力也明显减小;DSGZ模型的预测曲线与其实验数据曲线基本一致,DSGZ能够较真实地反映PMMA的力学性能。

To study the mechanical properties of outside mold decoration films,the true stress-strain curves under the corresponding conditions were obtained by uniaxial tensile tests of PMMA plastic sheets at high temperature with different temperature and strian rates,the coefficients of the viscoelastic constitutive model of DSGZ of different temperature and strian rate were calculated,and the predicted curve of DSGZ model and experimental data were compared and analysed.The analysis results show that at the same temperature the true stress,tensile ratio and yield strength would increase when the strain rate rose;at the same strain rate,the strain softening and yield phenomenon would decrease and then disappear,the true stress would also decrease when the temperature rose.The predicted curve of DSGZ model and experimental data were basically anastomotic,the mechanical properties of PMMA could be better reflected by the DSGZ model.