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Numerical Simulation of Liquid Composite Injection/Compression Moding. Part 1: Mesh Generation



K M. Pillai, C L. Tucker, Frederick R. Phelan Jr.


This paper presents a numerical simulation of the injection/compression type of liquid composite molding (LCI/CM), where the fiber preform is compressed to a desired degree at the same time as the resin is being injected into the mold. Due to the possibility of an initial gap at the top of the preform and out-of-plane heterogeneity in the multi-layered preform, a full three-dimensional (3D) flow simulation is essential. We propose an algorithm to generate of the mod cavity. Since different layers of the preform have different compressibilities, and since properties such as permeability are a strong function of the degree of compression, a simultaneous prediction of preform compression along with the resin flow is necessary for accurate mold-filling simulation. The algorithm creates a coarser mechanical mesh to simulate compression of the preform, and a finer flow mesh to simulate motion of resin the preform and gap. Lines connected to the top and bottom plates of the mold, called spines, are used as conduits for the nodes; this reduces the number of unknowns at a node point from the usual three components of displacement to a single scalar parameter marking position of the node along the spine. A method to generate a surface parallel to a given surface, thereby maintaining the thickness of the intermediate space, is used to construct the layers of the preform in the mechanical mesh. The mechanical mesh is further subdivided along the spines to create the flow mesh. The algorithm is robust and can generate mechanical and flow meshes from the shell mesh of any arbitrary three-dimensional mold shape. Since the algorithm assumes that gap height varies continuously with position in the shell mesh, it has the drawback of requiring a finer shell mesh near step changes in the mold thickness. Examples of the three-dimensional meshes generated by the algorithm are presented.
Polymer Composites


injection/compression, liquid composite molding, mesh generation, preform deformation, RTM


Pillai, K. , Tucker, C. and Phelan Jr., F. (2000), Numerical Simulation of Liquid Composite Injection/Compression Moding. Part 1: Mesh Generation, Polymer Composites, [online], (Accessed June 14, 2024)


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Created June 13, 2000, Updated October 12, 2021