Compostte Structures 13 (1989) 115-121 Correlation between Stress and Strain Based Polynomial Failure Criteria Wenchao Zhang* & K. E. Evans Department of Materials Scienceand Engineering, Universityof Liverpool, PO Box 147, Liverpool L69 3BX, UK ABSTRACT The correlation between stress and stram based polynomtal fadure crtterm ts considered. Spectfic attention ts patd to the clartfication of the dtsnnctton between the fundamental experimental tests requtred for these crttena Detaded exammatton of correlattons between these tests suggests that only one set of untamal tests (etther deforrnatton or loadmg tests) may be necessary to determme both stress and stram based polynomtal fadure crlterta, provided the effect of the transverse Potsson' s ratto ts constdered exphcttly. INTRODUCTION As advanced fibre reinforced composites gain in technological import- ance, a number of phenomenological criteria for predicting the strength of anisotropic composites have been developed. These have been derived primarily in stress space; m particular, the stress tensor polynomial failure criterion suggested by Tsai and Wu I and Wu 2 is considered the most rationally developed. However, the difficulty and complexity of determin- ing the interaction strength terms (F,j, i 4: j) from biaxial test conditions, which must be selected with great care 3 and measured with great accuracy, still obstructs the widespread use of such criteria. Bearing this m mind and considering, m many cases, the advantage of measuring strain to failure *On leave from Department of Mechanics,Tlanjm University, Tlanjin, People's Repubhc of China 115 Compostte Structures 0263-8223/89/$03.50 (~ 1989 Elsevier Science Publishers Ltd, England. Pnnted in Great Britain