统一型三次强度准则及其耦合项系数的确定

本文是在研究了复合材料统一型二次强度准则的基础上,对统一型强度准则的进一步研究。统一型强度准则应是三次型的,它比其它三次型强度准则,更适合于纤维增强复合材料的强度估算,也更简单。三次统一型强度准则会遇到三次耦合应力项强度系数的确定问题,本文为此作了讨论,同试验数据的比较表明,三次统一型强度准则更合理些。

THE CUBIC STRENGTH CRITERION OF INTEGRATED MODES AND DETERMINATION OF COUPLING COEFFICIENTS

This paper is a development of the quadratic strength criterion of integrated modes for fiber-reinforced composite materials. For simplification of evalution, the Cubic terms of the strength criterion in the reference 1] is neglected. From the point of view of principle, the criterion that includes the cubic terms has better accuracy, but it is not the truncating cubic tensor polynomial expansion. The criterion is mathematically expressed in a general cubic equation in terms of stress invariants. Considering two basic failure modes of unidirectionally fiber-reinforced composites, the criterion can be simplified. Two methods for determining cubic coupling coefficients are discused. This criterion has the characteristics more rational and simpler than that in the reference 4], and agre-es better with experimental data.