OPTIMAL DESIGN FOR RANDOMLY REINFORCED COMPOSITE STRUCTURES

The application of composites in structures excited the development of traditional optimal design problems and the formulation of qualitatively new optimal problems.'The principle of simultaneous optimal design of structure and material has become of practical importance.The simultaneous design principle was borrowed from nature.It extends the possibilities of improving the characteristics of structures.This principle is the further development of the idea of reinforcement, which is of great importance in engineering.Under the loading of the structure, the latter is in the complex stress-strain state.Actual stresses and deformations are different in different parts of the body.This circumstance is the main reason for using of nonhomogeneous and anisotropic materials.Removing of material from "unloaded" parts of the structures and, on the contrary, supporting the sharp stressed regions is the embodiment of the idea of reinforcing.Namely the application of composite material, which represents heterogeneous structures and is formed from the reinforcement (high modulus inclusions, fibers) and isotropic matrix, gives us new possibilities of wide variation of mechanical and physical properties in accordance with the stress state of structure and the type of loading.The variation is realized by means of redistribution of reinforcement concentration, changing of the shape of the inclusion and fibers orientation 'and other parameters of composite structure.The effective mechanical characteristics are varied in wide limits, what allows to obtain the structures with optimal properties.In present paper a number of solutions, characteristic optimal distributions of non-homogeneity for elastic structures, are represented.