Preform permeability prediction and influence of shear deformation

The accurate prediction of preform permeability has important implications for mould-filling simulation of liquid composite molding. The shear deformation of textile during draping process has a great influence on the local permeability of preform. Considering the permeability of yarn, the unified mathematical model for the resin flow in unit-cell was established, and the geometry model close to the real orthogonal unit-cell structure was built. Based on the Adams-Bashforth difference scheme and Chorin projection method, a numerical method with high resolution TVD schemes for solving the governing equations of resin flow was developed, and then the permeability was predicted using Darcy's law. The prediction results agreed well with experimental results, the validity of the algorithm was proved. On the basis of the permeability prediction of orthogonal unit-cell, the body-fitted coordinates system was employed and the governing equations were converted from physical domain to computational domain to simulate the resin flow in the sheared unit-cell and predict its permeability, then the relationship between the ratio of principal permeability and shear angle was studied. The results indicate that the method provided by this paper is convenient and effective.