Damage Mechanics Formulation of Cracking Evolution in Composite Laminates (2nd Report, FormuIation of Laminate Constitutive Equation)

摘要

In Part I of this study, the constitutive equation of a cracking layer was formulated introducing the new concept that a cracked lamina was replaced by an equivalent uniform work-softening layer. Part II formulates laminate constitutive equation in damage process using the results obtained in Part I and the laminate theory. In this formulation, influence of lamina stacking sequence is discussed through the magnification of an initial damage surface. It is shown that the damage evolution law in Part I can be used for general laminates even if the initial damage surface is enlarged, as long as cracking layer energy release rate is adopted as a cracking criterion. Present model is shown to reproduce experimental results with good accuracy. Finally, discussions about laminate stiffness reduction and stress path in damage process are given.