基于本构模型的发泡聚乙烯缓冲特性曲线研究

目的 建立EPE本构模型，并基于本构模型研究EPE缓冲系数-最大应力曲线。方法 通过静态压缩实验得到EPE应力-应变曲线，利用三次Bezier曲线拟合实验曲线，根据拟合曲线求得缓冲系数，从而得到缓冲系数-最大应力曲线。结果 利用三次Bezier曲线拟合得到了EPE分段本构模型，基于本构模型建立了EPE分段缓冲系数-最大应力曲线参数方程。本构模型、基于本构模型建立的EPE缓冲系数-最大应力曲线均收敛于分段点（0.3，0.1075），且当拟合应力值为0.4529 MPa时，得到缓冲系数最小值（5.0362）。结论 利用三次Bezier曲线拟合得到的应力-应变曲线与实验曲线有很好的拟合度，分别基于本构模型建立的和由实验数据得到的2条EPE缓冲系数-最大应力曲线有较好的拟合度，基于三次Bezier曲线拟合的本构模型研究EPE缓冲特性曲线是可行的。

Expanded Polyethylene Cushion Curve Based on Constitutive Model

The work aims to establish EPE constitutive model and study EPE buffer coefficient-maximum stress curve according to the model. The EPE stress-strain curve was obtained by static compression test. The cubic Bezier curve was used to fit the experimental curve. According to the fitting curve, the cushioning coefficient was acquired, and then the buffer coefficient-maximum stress curve was obtained. The sectioned EPE constitutive models were obtained through fitting with cubic Bezier curve. Based on the constitutive models, the parametric equations of buffer coefficient-maximum stress curve in EPE sections were established. Both the constitutive models and the EPE buffer coefficient-maximum stress curves based on the constitutive models were converged to the subsection point (0.3, 0.1075). When the stress value fitted was 0.4529 MPa, the minimum value of the buffer coefficient was 5.0362. The stress-strain curve of EPE fitted by the cubic Bezier curve has good fitness with the experimental curve. The two EPE buffer coefficient-maximum stress curves based on the constitutive model and the experimental data have good fitness. It is feasible to study the EPE cushion characteristic curve based on the constitutive model fitted by cubic Bezier curve.