This article investigates the material behavior within multiple-component systems. Specifically, a structural concrete element strengthened to flexure with externally-bonded fiber-reinforced polymer (FRP) material is considered. Enhancements of mechanical performances of the composite structural element resulting from synergies in the framework of the multiple-component system are studied. The research work comprises the determination of the constitutive relations for the materials considered separately as well as the investigation of materials’ response within a complex system such as the composite structural element. The definition of the material models involves a calibration of the model constants based on characterization tests. The constitutive relations are integrated into the finite element model to study the material behavior within the multiple-component system. Results obtained by finite element analysis are compared with experimental results from the literature. The finite element analysis provides valuable information about the evolution of some internal variables, such as mechanical damage accumulation. The material synergies find expression in the load-carrying capacity enhancement and the delay in the damage accumulation in concrete.

This paper presents a virtual experiment on the behaviour of a self-healing material from the family of cement-based composites, that contains a healing agent. A numerical model of a specimen made of a cement-based material, and containing a healing agent is subjected to the loading configuration of the four-point bending test, whereby the forces are applied in a quasi-static way. The response of the healed specimen is compared to the response of a specimen that doesn’t contain a healing agent. For the specimen that contains a healing agent, homogenization techniques are used to determine the characteristics of the equivalent material (cement-based composite / healing agent) in zones where damage and macro-cracking have occurred, i.e., zones in which the healing agent has been activated. The main result of this contribution is the formulation and validation of a numerical simulation approach suitable for modelling the mechanical behaviour of self-healing cement-based composites.

Currently, the widespread use of tubular belt conveyors is constrained by insufficient justification of the conveyor parameters. In the work, on the basis of the theory of the limiting equilibrium state of bulk load, equations of equilibrium of load on the belt of an inclined tubular conveyor are obtained. It is assumed that the belt was a rigid cylinder filled with bulk material in extreme equilibrium. Based on the obtained equilibrium equation, the analytical dependences of the limiting angle of inclination of the belt conveyor with a tubular belt on the degree of unfilling with the bulk load of the belt and the properties of the bulk load are found. From the analysis of these dependencies it follows that the limiting angle of inclination of the tubular belt conveyor depends on the angle of internal friction of the transported load, the angle of friction of the load on the conveyor belt, the angle of unfilling of the belt with load and does not depend on the radius of the conveyor belt.

Self-healing of a crack is a relatively novel technique allowing for the partial recovery of the initial mechanical characteristics of a structural element after some period of exploitation. By a widely accepted convention, self-healing is either autogenous or autonomous. The former is a mechanism inherent for cementitious composites (in particular—concrete), while the latter is an engineered process. Both autogenous and engineered healing have recently been the object of numerous studies. Despite the large amount of research work being carried out, the potential of this technique has not yet been fully realized. The article focuses on the modeling and the finite element simulation of the recovery of the initial material properties resulting from the sealing of cracks. The employed numerical procedure uses a constitutive relation for concrete based on the continuum damage mechanics. It captures both the strain-softening and the inverse process—the crack healing. Finite element simulations of benchmark cases illustrate the effect of self-healing. The numerically obtained constitutive relations for specimens with and without a healing agent are compared.