Damage evolution during the service life of structures made of anisotropic materials

In modern mechanical engineering, aviation, shipbuilding, aerospace, and energy industries, anisotropic materials with high specific strength and stiffness are increasingly used. However, their operational reliability is largely determined by complex aniso-tropic damage mechanisms that differ significantly from analogous processes in isotropic materials. When designing and operating products and structures made from polymer anisotropic materials, it is essential to determine the service life, which directly depends on the degradation of the material's physico-mechanical properties over time during the operation of engineering objects.The analysis of recent studies and publications shows that the degradation of mechanical properties of anisotropic materials under elastoplastic loading of engineering structures is insufficiently studied and is the subject of an extensive body of scientific work. The purpose of this article is to develop a methodology for calculating the kinetics of damage accumulation in anisotropic materials, taking into account changes in volume and shape of the material under elastoplastic loading of engineering structures.The work derives relationships characterizing the kinetics functions of damage accumulation based on changes in volume and shape of a representative elementary volume (REV) during the operation of engineering objects made of anisotropic mate-rials. The limits of variation in volume and shape functions from the start of loading to failure are established. A generalized damage tensor function for anisotropic materials is obtained, which accounts for changes in volume and shape as a result of damage accumulation during the operation of engineering objects.