Prediction of elastic behavior of plain weft-knitted composites

Abstract

Design and analysis of parts constructed from weft-knitted textile composites need the elastic and fracture behavior of the composite. To avoid time-consuming and expensive experimental procedures, micromechanical models and finite element simulations can be used to estimate stiffness matrix of these composites. In the present study, at first, a 3D model of a plain weft-knitted fabric is presented. Then a micromechanical approach is proposed to derive the mechanical properties of the weft-knitted composite using this geometrical model. A finite element simulation is carried out to extract the elastic properties of the composite as an alternative procedure. Finally, obtained moduli from both methods are validated by comparing them with existing experimental values. Results show a good agreement between the calculated and measured data. It can be concluded that the proposed micromechanical approach can predict weft-knitted composite behavior well without any great effort; however, the finite element analysis gives acceptable results too. The effects of composite variables on the stiffness are investigated and discussed.

Experimental and numerical study on stiffness and damage of glass/epoxy biaxial weft-knitted reinforced composites

“…Several finite element and analytical approaches have been proposed to predict the mechanical performance of knitted reinforced composites in terms of composite stiffness and strength. 16–18 Shekarchizadeh et al. 18 derived the stiffness matrix of plain weft-knitted reinforced composites through a micromechanical approach.…”

The effect of core geometry on flexural stiffness and transverse shear rigidity of weight‐wise identical corrugated core sandwich panels reinforced with 3D flat spacer knitted fabric

“…As is shown in Table 3, in line with the work of Ramakrishna [ 19 ] and ASTM D3039 [ 20 ] standard, modulus of elasticity E 1 and E 2 along the wale and course directions of the lamina were experimentally determined using tensile tests. Other characteristics such as modulus of elasticity along thickness of sheet, E 3 , shear modulus, and Poisson's ratio of the sheets, as is shown in Table 4, were determined in accordance to the analytical method proposed by Shekarchizadeh et al [ 21 ]…”

Numerical Modelling of the Mechanical Behaviour of Biaxial Weft-Knitted Fabrics on Different Length Scales

“…A simulation approach would reduce the developing time and cost. Therefore, many models for various textile structures such as woven fabrics [9,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29], 3D woven fabrics [30,31,32,33,34,35,36], non-crimp fabrics [37], weft-knitted fabrics [17,38,39,40,41,42,43,44,45,46,47], and multiaxial warp-knitted fabrics [48] were developed. The models could be classified by the mathematical approach: Analytical [44,49,50] or numerical models, in which they are divided into smaller groups by the length scale of the modelled components into three categories: Micro-scale models [20,21,35,36,39], meso-scale models [16,17,18,19,22,31,32,33,34,37,40,41,42,…”

“…A composite unit cell with 3D tetrahedral elements coupled with a matrix mesh helps to predict the mechanical behavior of the weft-knitted reinforced composite. Similar approaches using a meso-scale model on a repeated unit cell are also used for numerical analysis of the mechanical behavior of the weft-knitted structure [40,42,46] or weft-knitted reinforced composite structure [38,47,53,54]. The obtained properties can be transferred to macro-scale model for further analysis.…”