A modification of the Tsai-Wu failure criterion for the biaxial strength of paper

Prediction of the in-plane biaxial strength of paper by the Tsai-Wu failure criterion has in general proved to be in good agreement with experimental data. However, the Tsai-Wu criterion overestimates the strength in some parts of the biaxial tension region. This shortcoming can be corrected by adding a pair of cubic terms to the existing Tsai-Wu criterion. The modified Tsai-Wu criterion presented here predicts the biaxial strength of paper more accurately than the Tsai-Wu
criterion. The extra pair of parameters introduced is determined ftom data obtained by standard tests.