Abstract This work focuses on the constitutive modeling of a graded porous polymer pipeline coating based on X-ray micro computed tomography (XRMCT). Previous work has revealed that finite element (FE) models generated from XRMCT scans of cylindrical coating specimens reproduce their response in uniaxial compression accurately. In this work, we use FE models generated from XRMCT scans to study the pressure-sensitive yield strength of the porous coating. Since the coating is known to have a graded pore structure through its thickness, data from an XRMCT scan of a full coating sample is divided into twenty-four sublayers across the coating thickness, from which FE models are generated. These FE models are used to perform numerical limit analyses to map the yield locus for each sublayer, which are utilized to calibrate an analytical yield surface. A strong correlation is found between the fitted yield surface parameters and the average porosity of the sublayers. This observation is used to propose a constitutive model where the yield strength depends on the porosity and its evolution with deformation. The constitutive model is implemented as a user subroutine in a commercial explicit FE solver and validated against experimental component tests, showing good agreement.

中文翻译：

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基于 X 射线计算机断层扫描的梯度多孔聚合物本构建模

摘要 这项工作的重点是基于 X 射线显微计算机断层扫描 (XRMCT) 的梯度多孔聚合物管道涂层的本构建模。以前的工作表明，从圆柱形涂层试样的 XRMCT 扫描生成的有限元 (FE) 模型准确地再现了它们在单轴压缩中的响应。在这项工作中，我们使用从 XRMCT 扫描生成的有限元模型来研究多孔涂层的压敏屈服强度。由于已知涂层在其厚度范围内具有分级孔隙结构，因此将整个涂层样品的 XRMCT 扫描数据在涂层厚度上分为 24 个子层，并从中生成 FE 模型。这些有限元模型用于执行数值极限分析，以绘制每个子层的屈服轨迹，用于校准分析屈服面。在拟合的屈服面参数和子层的平均孔隙率之间发现了很强的相关性。该观察结果用于提出一个本构模型，其中屈服强度取决于孔隙率及其随变形的演变。本构模型在商业显式有限元求解器中作为用户子程序实现，并针对实验组件测试进行验证，显示出良好的一致性。