Stress-strain condition of flat manhole covers under internal pressure in presence of mechanical defect with different dislocation on surface

Abstract

One of the most common damage to the structural elements of vessels and apparatus of hydrocarbon processing plants is mechanical damage, which mainly occurs during repair and installation operations. One of the prerequisites for the occurrence of this type of defects is the use of a locksmith tool and other devices, tools and devices, upon contact of which with the surface of the elements to be repaired and mounted, risks, scratches, balls, nicks and other damage are formed. The vast majority in terms of the degree of occurrence on the surface of structural elements of all defects of a mechanical nature occupy scratches. There is practically no technical device operating in a hazardous production facility and does not have at least one of the elements of this type on the external surface. With respect to the surface on which the scratches are arranged, these defects can be both small geometrical dimensions and sufficiently extended. Such defects generally do not limit the life cycle of the object, but can have a significant effect on the redistribution of the stress-strain state in the element. The redistribution of the stress-strain state can serve as an initial stage for the generation of potential fracture sites from the concentration of increased stresses in these zones. Also, not only the presence of a scratch, but also the length, as well as the nature of the location on the surface of the element, can affect the stressed-deformed state of the element. Therefore, the actual work is a study of the change in the stress-deformed state of the flat manhole cover with a scratch, the arrangement of which on the surface has various options. In this work, the stress-strain state of the flat manhole cover is simulated depending on the change in the angle of inclination and the location of the scratch on it relative to the central zone.