Co-simulation Technology of Mold Flow and Structure for Injection Molding Reinforced Thermoplastic Composite (FRT) Parts

The co-simulation of mold flow and structure plays an important role in the design of injection molded fiber-reinforced thermoplastic (FRT) parts. The mold flow model is usually a single-part model, that is, the FRT part itself, but the mechanics model is often a multi-part model, an assembly of the FRT part and others. As the material properties of the FRT part can only be obtained from mold flow simulation, how to use them in structure simulation leaves a great difficulty to engineering applications. This paper presents an effective method to convert material data from mold flow simulation software Moldflow to structure simulation software Abaqus for thin-walled parts that can be meshed into 2D shell elements. First, a combination of hash-map and vector is used for quick element storage and search. The hash-map is three dimensional, indexed by the integer coordinates of the center of the cubes obtained from spatial subdivision. Each node of the hash-map contains a vector to store the elements, whose centroids fall in the same cube. Second, a fiber redirection method is proposed, aiming to adjust the fibers from lying within the flow elements to lying within the structure elements based on the coordinate transformation theory. Finally, the Poisson's ratio of the Tandon-Weng model is modified, which is the default model for Moldflow to measure the properties of the FRT material, but its Poisson's ratio is not correct. Test cases show that for an Abaqus FEM model, containing about 200,000 elements in total, and about 100,000 of them belonging to the FRT part, the conversion of material data can be done completely in less than 10 min with the method proposed in this paper. Importantly, the element matching rate can be up to 99%, and finally the accuracy of the structure simulation is significantly improved.