Defining Multi-Layered Composite Structure in Finite Element Analysis

 In modern structural analysis, multi-layer composite materials are often encountered. These composites frequently appear as a complete shell structure, made up of multiple layers stacked on top of each other. The angles, thicknesses, and materials of the layers may all vary. For the analysis of such composite materials, simulation software needs to provide relevant features, with users inputting data based on the actual materials.

The WELSIM composite parameter input provides a simplified method. This article introduces the steps to define composites.

1. Create a new FEM project.
2. Add two material objects, named Glass and Plastic Film, respectively.

3. Double-click the Glass material object to enter the editing mode. Enter the initial density of 2.5e-6 kg/mm³, Young’s modulus of 70 GPa, Poisson’s ratio of 0.2, plastic yield stress of 80 MPa, hardening parameter of 500 MPa, and hardening exponent of 0.8. Add Orthotropic Brittle Failure properties with the default parameters set to 0.

4. Double-click the Plastic Film material object to enter the editing mode. Enter the initial density of 2.5e-6 kg/mm³, Young’s modulus of 100 MPa, Poisson’s ratio of 0.2, plastic yield stress of 10 MPa, hardening parameter of 20 MPa, and hardening exponent of 0.5. Add orthotropic brittle failure properties with strain at the beginning of tensile failure set to 0.6, maximum tensile strain set to 0.7, and the maximum tensile strain for element deletion set to 0.8.

5. Add a plane shape to represent the shell structure. Users can also import a real shell structure. In the properties window, set the Structural Type to Multi-Layer Shell structure.

6. Once the Structural Type is set to Multi-Layer Shell, the table window is activated to edit layer data. This allows users to define the number of layers, angle, thickness, Z position, and materials for each layer. Here, a total of three layers are defined, with thicknesses of 1 mm, 0.5 mm, and 1 mm, and materials of Glass, Plastic Film, and Glass, respectively.

7. At this point, the multi-layer shell structure is defined and ready for subsequent analysis and computation. For example, an OpenRadioss input script can be generated to view the input layer data. As shown in the picture below, the material information and multi-layer shell structure properties are fully defined for solver.

Conclusion

This blog demonstrates the definition of a multi-layer shell structure and the associated material properties. This is the first step in composite material analysis. WELSIM makes it easy and quick to define multi-layer structures. This feature has been implemented in the 2025R2 development version and will continue to be optimized in future versions.

WelSim and the author is not directly associated with or the OpenRadioss development team or institutions. OpenRadioss is cited here only as a reference for the technical blog article and software usage.

定义有限元分析中，复合材料的多铺层结构

现代结构分析中，常常会遇到多铺层复合材料。这些复合材料常常以板壳的整体结构形式出现，内部由多层铺层叠加而成。铺层的角度，厚度，材料都有可能不同。对于这种符合材料的分析，仿真软件需要提供相关的功能，由用户根据实际材料输入数据。

WELSIM复合材料的参数输入提供了简洁的方式。本文介绍定义复合材料的步骤。

1. 新建一个FEM工程。

2. 添加两个材料节点，分别命名为玻璃Glass，和塑性薄膜Plastic Film。

3. 双击玻璃材料节点，进入编辑模式。输入初始密度 2.5e-6 kg/mm3, 杨氏模量70GPa, 泊松比0.2，塑性屈服应力80MPa, 硬化参数500MPa，硬化指数0.8。并添加正交各项异性脆性失效属性，保持默认参数为0。

4. 双击塑性胶片材料节点，进入编辑模式。输入初始密度 2.5e-6 kg/mm3, 杨氏模量100 MPa, 泊松比0.2，塑性屈服应力10MPa, 硬化参数 20MPa，硬化指数0.5。添加正交各项异性脆性失效属性，拉伸失效应变为0.6，最大拉伸应力为0.7，单元删除最大拉伸应变为0.8。

5. 添加一个平面模型，用于表示板壳结构。用户也可以导入一个真实的板壳模型。并在属性窗口中将结构类型设置为多层壳体结构。

6. 当结构类型设置为多层壳体后，表格窗口被激活用于编辑层信息。支持用户定义，层数，铺层角度，铺层厚度，铺层位置高度，和每个铺层的材料。这里定义一共3个铺层，每层的厚度分别是，1 mm, 0.5 mm, 1 mm，材料分别是玻璃，塑性胶片，和玻璃。

7. 至此，多铺层板壳结构就定义完成了。可以用于后续的分析与计算。如可以生成OpenRadioss的输入文件，查看输入的铺层数据。如下图所示，材料信息和铺层板壳结构属性都定义完整。可以用于求解器的计算。

总结

本文演示了多铺层板壳结构的定义，和相关材料属性的定义。这是复合材料分析的第一步。WELSIM可以方便快速的定义多铺层结构。此功能已经在2025R2开发版中实现，会在以后的版本中不断优化。

WelSim与作者和OpenRadioss开发团队与机构没有直接关系。这里引用OpenRadioss仅用作技术博客文章与软件使用的参考。