Polyurethane foam (PUF) is a porous material and significantly affected by compressive loads. Under a uniaxial compressive load, the PUF exhibits various types of material nonlinear behavior under varying conditions, such as density, foaming direction, and strain rate. This study investigates the nonlinear behavior of a PUF through phenomenological approach. A Frank–Brockman–Zairi elasto-viscoplastic constitutive model was adopted to investigate the behavior of PUFs with different densities, directions, and strain rates when subjected to compressive loads. The proposed model was discretized using the implicit time integration algorithm and implemented into a user-defined subroutine of ABAQUS. In this study, parameter determination method was also implemented to identify material parameters containing the constitutive equations. Furthermore, the detailed process of determining the material parameters containing the shape of the work-hardening rate–stress curve dependent on the type of material behavior was presented. Consequently, the macroscopic material response of the PUF, such as the stress–strain curve, can be predicted based on the proposed constitutive model. In future studies, the mechanical behavior of porous materials can be analyzed more successfully by supplementing the constitutive model. This can allow the model to simulate the complex plastic flow of porous materials after yielding that is presently difficult to implement.

聚氨酯泡沫 (PUF) 是一种多孔材料，受压缩载荷的影响很大。在单轴压缩载荷下，PUF 在不同条件下表现出各种类型的材料非线性行为，例如密度、发泡方向和应变率。本研究通过现象学方法研究 PUF 的非线性行为。采用 Frank-Brockman-Zairi 弹粘塑性本构模型来研究不同密度、方向和应变率的 PUF 在承受压缩载荷时的行为。所提出的模型使用隐式时间积分算法进行离散化，并在 ABAQUS 的用户定义子程序中实现。在这项研究中，还实施了参数确定方法来识别包含本构方程的材料参数。此外，介绍了确定材料参数的详细过程，包括取决于材料行为类型的加工硬化率-应力曲线的形状。因此，PUF 的宏观材料响应，例如应力-应变曲线，可以基于所提出的本构模型进行预测。在未来的研究中，通过补充本构模型可以更成功地分析多孔材料的力学行为。这可以让模型在屈服后模拟多孔材料的复杂塑性流动，目前难以实现。例如应力-应变曲线，可以根据建议的本构模型进行预测。在未来的研究中，通过补充本构模型可以更成功地分析多孔材料的力学行为。这可以让模型在屈服后模拟多孔材料的复杂塑性流动，目前难以实现。例如应力-应变曲线，可以根据建议的本构模型进行预测。在未来的研究中，通过补充本构模型可以更成功地分析多孔材料的力学行为。这可以让模型在屈服后模拟多孔材料的复杂塑性流动，目前难以实现。