Property Modelling and Durability of Composite Materials

Abstract

Composite materials are considered as complex systems with corresponding system attributes. The necessity of studying the properties and structure of composite materials as a whole as systems connected by relationships that generate integrative qualities is pointed out. When synthesizing a composite, it is proposed to use the principle of simulability: a complex system is represented by a finite set of models reflecting a certain facet of its essence. This makes it possible to investigate a certain property or group of properties of a building material using one or several simplified (narrowly-oriented) models. Identification of new properties and entities is done on the basis of building up a set of simplified models (the reflection of a complex system as a whole is provided by the interaction of simplified models). Using the principle of purposefulness makes it possible to describe the quality of the material by some functionality for an integrated system. Internal causal relationships, the existence and function of the composite material (system) are based on the principle described physicality (any system regardless of the inherent physical laws of nature, possibly unique); no other laws are required to describe the operation of the system. The study of material properties is made on the basis of parametric identification of kinetic processes of formation of physical and mechanical characteristics of composite materials. For special purpose building materials, a number of particular criteria (properties) are determined, and their description is formalized using the principal component method (reducing the dimensionality of problems in assessing the quality of a material with simultaneous determination of a set of independent partial criteria). The results of the practical application of the method for evaluating the quality of composite materials with special properties are presented. Among the priority criteria were: strength, density and porosity of the material. Their dependences on the coded volume fractions of aggregate and filler were obtained by methods of mathematical experiment planning. It is shown that for most properties one can confine oneself to second-order differential models; each of the properties of the composite is considered as one of the particular criteria. Appendices are given to the development of composite materials for various purposes. Using the methods of control theory, an analytical description of the durability of the composite material is given; parametric identification is reduced to the determination of time constants in a second-order differential model, taking into account their dependencies on the prescription and technological parameters. Assessment of durability of a radiation protective composite taking into account dependences of the main properties on the prescription and technological parameters received on the basis of the generalized model is made.