Numerical simulation with experimental validation of the structural reaction injection moulding of 3D continuous fibre reinforced polyurethane foam

Abstract

Sandwich composite materials are established in the industry. Polyurethane foam reinforced with spacer fabric represents an innovative solution for a core in this field. It is manufactured in the Structural Reaction Injection Moulding (SRIM). This paper describes new investigations that provide the base for component and process design when using this Interpenetrating Phase Composite (IPC). Filling studies were carried out for this purpose in three moulding tools with different cavities with and without spacer fabric. It is shown that the PUR foam expansion and the foam bulk density are clearly influenced by the sprue type, cavity design and spacer fabric. Simulations are necessary to investigate all process-structure-property relationships in detail and to enable a user-friendly and efficient design of material and process. Adequate mathematical models to simulate the transport of mass, heat and momentum in the SRIM are presented in this paper. The resistance to the expansion process caused by the porous structures in the domain were taken into account. The transport of momentum in the mould is described with the Navier–Stokes-Brinkman equations which in the limit of the permeability tensor reduces to the Navier–Stokes equation. The model equations are solved numerically and the results show reasonable agreement with the experimental data.

Analysis of stentering and heat-setting on the structure and compression behavior of 3D mesh fabric using X-ray micro-computed tomography and microscopic modeling

“…18,19 , but the spacer monofilament geometries were still not realistic, and the material models were linear elasticity. X-ray micro-computed tomography (μCT) was used to scan spacer fabrics with meshed 7,8,[20][21][22][23] or closed outer layers [24][25][26][27] to obtain authentic geometries of spacer monofilaments. The true geometries and material nonlinearity of spacer monofilaments were employed to establish FE models for those fabrics with closed surfaces by treating the outer layers as isotropic and elastic plates.…”

Quantitative analysis of monofilament architecture in three-dimensional mesh fabric using micro X-ray computed tomography

“…[10][11][12][13] The mCT technique has been adopted to scan spacer fabrics to obtain their 3D geometric details. 1,4,5,[14][15][16][17][18][19] However, mCT scanning results in a large amount of voxel data, and automatically processing the data to intricate textile structures and a computable dataset for further mechanical and fluid simulation is difficult. 10 Hou et al, 14 Glombikova et al, 16 and Gao et al 17 scanned and reconstructed different spacer fabrics, but the reconstructions were used for general observations without any quantitative analysis.…”

“…10 Hou et al, 14 Glombikova et al, 16 and Gao et al 17 scanned and reconstructed different spacer fabrics, but the reconstructions were used for general observations without any quantitative analysis. Sch€ afer et al 18 scanned two spacer fabrics and directly imported the mCT data into the digital material laboratory software tool GeoDict V R of the Math 2 Market GmbH (Kaiserslautern, Germany) for calculating the flow through the spacer fabric in all three coordinate directions. Hou et al 15 and Liu and Hu 4 scanned a spacer fabric with closed outer layers along the thickness direction and extracted the centroids of the spacer monofilament cross-sections in each slice by image processing to digitize a unit cell including eight spacer monofilaments for finite element (FE) simulation.…”

“…10–13 The µCT technique has been adopted to scan spacer fabrics to obtain their 3D geometric details. 1,4,5,14–19 However, µCT scanning results in a large amount of voxel data, and automatically processing the data to intricate textile structures and a computable dataset for further mechanical and fluid simulation is difficult. 10 Hou et al., 14 Glombikova et al., 16 and Gao et al.…”

“…Schäfer et al. 18 scanned two spacer fabrics and directly imported the µCT data into the digital material laboratory software tool GeoDict® of the Math 2 Market GmbH (Kaiserslautern, Germany) for calculating the flow through the spacer fabric in all three coordinate directions. Hou et al.…”