The behaviour of structures made of brittle or plastic materials, such as rock, concrete, metals and composites, under the action of thermal, mechanical, electromagnetic and fluid-flow forces, is largely depicted by the interactions of defects present in these materials. Thus the quantitative evaluation of interactions among the various defects such as inclusions, holes, inhomogeneities and cracks, is of critical importance in the design of economical and safe multiply-connected structures. Some of these coupled and defect-interaction boundary value problems under certain fields of forces can be solved analytically. In general, however, such complicated problems (contact, engineering mechanics of composite structures, fracture mechanics, thermo-mechanical, etc.) can be treated only by appropriate numerical techniques with appropriate physico-mathematical formulation and experimental techniques. The research will investigate certain engineering problems concerning the behaviour of structures made of materials, such as rock, concrete, metals and composites, under the influence of one or more fields of forces: thermal, mechanical, electromagnetic and fluid-flow. This investigation will be carried out by applying mathematical methods (integral transforms and equations, singular integral equations, theory of fractals, etc.); modern numerical methods (finite and boundary elements) and fractal theory supported by interactive computer graphics; and appropriate experimental methods. The participants from the NIS have developed rigorous analytical methodologies to attack these problems but not numerical and experimental methods to the same degree. On the other hand, participants from INTAS member countries have developed computer-aided numerical schemes and experimental methods. A major aim of this programme, therefore, is the coupling of these approaches through fruitful co-operation and exchange of knowledge between scientists from the NIS and from INTAS member countries in order to attack successfully the aforementioned engineering problems.