Mathematical and numerical simulation of geometry and mechanical behavior of sandwich composites reinforced with 1 × 1-Rib-Gaiting weft-knitted spacer fabric; compressional behavior

The first and most important step in the numerical analysis of the mechanical properties of complex structures is to create an accurate geometrical model. This paper aims to generate a mathematical model for the geometry of weft-knitted spacer fabrics in order to use in the numerical analysis of the mechanical properties of sandwich composites. For this purpose, the equations of path yarn were derived. A mathematical model was developed for the geometry of 1 × 1-Rib-Gaiting weft-knitted spacer fabric using derived equations. In order to simulate the matrix of the sandwich composite, a novel approach was proposed to apply the matrix to the structure of the generated model. The compressional behavior of sandwich composites reinforced with weft-knitted spacer fabrics was simulated using a generated model in the ABAQUS software. The maximum error of 4.04% and 4.2% were recorded in the prediction of geometry and compression modulus of sandwich composites, respectively. In addition, the results of the numerical and experimental compression test showed that the pile yarns have the main role in the compressional behavior of sandwich structures reinforced with spacer fabrics. The maximum Mises and shear stresses are occurred at the midpoint of pile yarns and connection points between piles and layers, respectively.