Numerical investigation of damage propagation of woven composite using decoupled multi-scale method

Abstract

Progressive damage behavior of woven composite structure is simulated, based on decoupled multi-scale damage analysis to consider microscopic woven structure. Since woven composites have complex microstructure, it is difficult to predict their damage behavior by only experimental approaches. Evaluating damage process is important for the assessment of safety, and numerical method of simulating damage behavior is demanded. In this paper, decoupled multi-scale analysis method was adopted. The constitutive law used in analysis of structural member scale (macroscopic scale) was identified by analysis of weave-structure scale (microscopic scale) and two-scale simultaneous analyses are no longer necessary. In microscopic scale, representative unit cell (RUC) of woven structure was considered, and in-plane periodicity was assumed to reflect inhomogeneity caused by woven structure. Microscopic analysis was carried out to identify the constitutive law which is used in the macroscopic analysis. Transverse crack of fiber bundle was modeled using enhanced continuum damage mechanics (ECDM) model. Fiber/matrix interface debonding was also modeled by cohesive zone model (CZM). In the macroscopic scale, structural member was modeled. Macroscopic analysis was carried out to investigate initial damage occurrence location and damage process. Damage progress was modeled by stiffness degradation, using CDM model and microscopic analysis results were reflected to determination of macroscopic damage variables. Four-point bending test of macroscopic specimen was carried out for validation of the analysis. Damage observation showed the macroscopic analysis effectively simulated damage occurrence and propagation. Localization analysis was then carried out to investigate damage behavior of woven structure, reflecting deformation history of macroscopic initial damage occurrence location to microscopic analysis. By comparing the analysis to cross-section observation, initial damage simulation showed good agreements with experiment.

Keywords

• composite materials
• numerical method
• multiscale approach
• homogenization
• woven structure
• structural mechanics
• damage prediction