On the methodologies of stress analysis of composite structures

Abstract

New, advanced experimental approaches, based on the principle of physical modelling of real events, have been applied to develop three new groups of experimental methods of stress analysis. They are briefly presented below and their efficacy is illustrated by examples: isodyne methods, strain gradient methods, and thermoelastic effect method. All three are nondestructive methods. The first two methods can be used to determine stress components or their spatial derivatives in materials that are transparent either in the visible band of electromagnetic radiation, or in the infrared, or--in principle--microwave band. The third group of methods is based on application of the thermoelastic effect which occurs in all bodies having non-zero values of the thermal expansion coefficient. These methods appear to be promising. For instance, they allow one to easily distinguish between elastic longitudinal and shear waves.