The Methodology of the Determination of Accumulated Damage Level and Achievement of the Limit State in Ferromagnetic Steel Structures

Abstract

The insurance of the safety of extended facilities, such as pipeline systems, raises the issue of continuous monitoring of their technical condition and control of accumulated damage. A similar problem arises in the operation of hazardous facilities with a large surface area, which include oil and gas technology reactors, reservoirs. The complexity of the problem lies in the large uncertainty of the state of the system, the initial conditions of which are not always known. At the same time, such objects are distinguished by a non-uniform distribution of mechanical properties and a non-uniform stressed-deformed state. It is shown that the traditional ways of ensuring the security of complex systems exhaust their resources, because the destruction occurs despite the improvement of diagnostic tools. The authors, formulating a new approach to assessing the degree of resource exhaustion, proceed from the fact that it is necessary to distinguish the resource of a structural material and the resource of a structure, while the structural material when introducing energy from the outside tends to include various mechanisms of adaptation to external influences. The level of accumulated damage in metal structures is determined by monitoring changes in the electrical and magnetic characteristics of metal during cyclic loading. The dependence of the change in electrical and magnetic characteristics on the number of loading cycles has an extremum, which determines the limiting state of the metal.

Destruction of Epoxy-Based Composite Materials under the Influence of Impact Load

“…On the other hand, all complex structures are arranged in such a way that many of their properties are determined by the ratio of ordered and chaotic parts. For polycrystalline solids we can distinguish the so-called Frank grid which is a set of connected dislocations [10]. From this point of view hybrid composite materials should have a tendency to increase the impact viscosity as the test temperature decreases.…”

“…In the zone of destruction there are three peaks, the interpretation of the nature of which is possible with the involvement of the deformation curve of the composite material. Figure 5 shows such a diagram [10]. The authors of [10] pay attention to the fact that the presence of non-equilibrium breakdowns on the downward branch of deformation may indicate the existence of additional equilibrium states of the medium which has not been realized.…”

“…Figure 5 shows such a diagram [10]. The authors of [10] pay attention to the fact that the presence of non-equilibrium breakdowns on the downward branch of deformation may indicate the existence of additional equilibrium states of the medium which has not been realized. This correlates with our assumption about the influence of the hierarchy of the structure of a composite material on the destruction process.…”