Grey Systems: Theory and Application

Purpose – The purpose of this paper is to present an analytical modelling approach to predict engineering elastic constants of 3D woven orthogonal composites (3DWOCs) at representative volume element (RVE) level using a volume averaging method.

Design/methodology/approach – The present analytical modeling approach uses a more realistic internal geometry representation of the 3DWOC. A RVE which is a repeating element at macroscopic level is first identified and volume proportions and engineering elastic constants of various constituents (matrix and family of constituent tows; warp, weft and z-fibers) which contribute to the global stiffness of RVE/composite are next determined. For accurate predictions, emphasis is given to accurate measurements of micro-structural data such as fiber volume fraction and fiber volume proportion of constituent tows and internal geometry of the 3DWOC structure-in particular, undulation of z-fibers. Microscopic study has been conducted in this regard.

Findings – The predicted engineering elastic constants are compared against experimental data, showing a strong correlation between predicted and experimental values.

Practical implications – The methodology presented in the paper can be used for accurate computation of the engineering elastic constants of 3DWOCs. The method can also be used for other types of 2D or 3D textile composites such as 2D woven composites, 2D braided composites, 3D woven angle interlock composites and 3D braided composites.

Originality/value – The paper succeeds in relating the micro-structural properties and analytical model for the accurate prediction of engineering elastic constants.