Multi-Scale Modeling the Mechanical Properties of Biaxial Weft Knitted Fabrics for Composite Applications Mohammad Javad Abghary 1 & Reza Jafari Nedoushan 2 & Hossein Hasani 1 Received: 23 October 2016 / Accepted: 24 October 2016 # Springer Science+Business Media Dordrecht 2016 Abstract In this paper a multi-scale numerical model for simulating the mechanical behavior of biaxial weft knitted fabrics produced based on 1×1 rib structure is presented. Fabrics were produced on a modern flat knitting machine using polyester as stitch yarns and nylon as straight yarns. A macro constitutive equation was presented to model the fabric mechanical behavior as a continuum material. User defined material subroutines were provided to implement the constitutive behavior in Abaqus software. The constitutive equation needs remarkable tensile tests on the fabric as the inputs. To solve this drawbacks meso scale modeling of the fabric was used to predict stress–strain curves of the fabric in three different directions (course, wale and 45°). In these simulations only the yarn properties are needed. To evaluate the accuracy of the proposed macro and meso models, fabric tensile behavior in 22.5 and 67.5° directions were simulated by the calibrated macro model and compared with experimental results. Spherical deformation was also simulated by the multi scale model and compared with experimental results. The results showed that the multi-scale modeling can successfully predict the tensile and spherical deformation of the biaxial weft knitted fabric with least required experiments. This model will be useful for composite applications. Keywords Biaxial weft knitted fabric . Multi-scale finite element modeling . Tensile behavior in various directions . Fabric spherical deformation 1 Introduction Nowadays, technical textiles, which have excellent mechanical behavior at the time of application, have attracted attention of engineers and designers. The use of these textiles in Appl Compos Mater DOI 10.1007/s10443-016-9551-y * Mohammad Javad Abghary mj.abghary@gmail.com 1 Department of Textile Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran 2 Department of Mechanical Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran