Theoretical-experimental study of mechanical behavior in 3D composites under quasi-steady damage

Composite materials are used to manufacture all modern aircrafts and aircraft engines. The development of these materials is labour-intensive and expensive, as it is necessary to carry out extensive experimental studies of anisotropic material properties. There are also certain constraints which make it impossible to obtain some material properties via experiments. There are various numerical techniques to reduce development time and costs for such materials, e.g. construction of a virtual prototype, a series of numerical experiments and use of different varieties of continuous damage mechanics method (CDM). Continuous damage mechanics method (CDM) is a popular tool for modelling damage development in reinforced composites. It is based on the assumption that any given volume of a damaged material can be equivalently changed by the undamaged volume of material with a decreased elastic modulus. Thus, material damage is only reflected by lowered elastic properties; and damage growth is reflected by a degree of material’s elastic modulus reduction. APDL macros was developed for the application of a variant of this method in finite elements analysis problem. The method of building an idealized virtual prototype of a 3D-reinforced composite material using tomography is considered in the paper. The method of determining effective elastic properties of a 3D-reinforced composite material by a series of numerical experiments is presented here. Continuous damage mechanics is used for obtaining materials’ strength parameters. Acoustic emission diagrams and stress-strain relations for material specimens in uniaxial tension and shear stress states are shown. Numerical modelling results are compared with the experimental data obtained.