Behavior of 3-D orthogonally woven composites under tensile loading

A three-dimensional woven fabric composite strength model is presented for predicting the failure behavior of three-dimensional orthogonally woven com posites under on-axis, uniaxial, static tensile loading. The representative unit cell is discretized into sections and elements. The method predicts t he stress levels at which secondary failures take place at element level. T he effect of secondary failure is considered for further analysis, and the ultimate tensile-failure strength and failure strain are predicted. It is o bserved that for the same fiber volume fractions, 3-D orthogonally woven co mposites show a significant increase in through-the-thickness properties wi thout a comparable reduction in in-plane properties. It is found that the a ssumed cross-sectional geometry of the strand with the same overall fiber v olume fraction does not make a significant difference to the elastic and st rength properties, and hence a square cross-section can be considered.