ИСТИНА

This paper presents an approach to the formulation of models characterizing nonlinear deformation and damage of composite materials and includes the consideration as the simplest model as more complex ones. In this research, the assumptions to build up a theory for failure prediction in laminated composites are presented, which are generalized enough to serve as the basis for explanation of current models and for further development of modelling theory. The presented approach is a phenomenological one and introduces degradation parameters explicitly influencing on the stiffness characteristics of composite materials. The main part of the research focuses on development of simplified constitutive relations suitable for practical application in testing and characterization of composite materials. Additionally, the rest of this work is dedicated to the extension of formulated approach to capture and take into account the complex effects such as initial nonlinear shear deformation behavior of laminated composites and the influence of high strain rate on strength properties. The results obtained show a good correlation between the predictions obtained with proposed modelling method and analyzed experimental data.