MODELING THE ACTION OF THE SHOCK-WAVE LOAD ON THE HULLS ELEMENTS OF VEHICLES

To study the effect of shock wave load on the body elements of vehicles, a setting has been developed that takes into account the mobile nature of this load. A specialized parametric finite-element model of the body layout has been created armored-carrier, taking into account the peculiarities of the studied process. The problem of determining the stress-strain state armored-hulls solved in static and dynamic formulation. The space-time distributions of components and characteristics of the stress-strain state of the investigated model armored-carrier of armored hulls are given. The results of research in the used formulations indicate the need to solve the problem in a complete dynamic formulation with account for plastic deformations. This establishes a new methodology for the rational choice of engineering solutions. Keywords: stress-strain state; armored carrier; armored hulls; shock wave; moving load; sample; rational constructive decision

Effects of wave loads on the strength of semisubmersible drilling platform

In order to reduce the failure risk of the structures of semisubmersible drilling platform during its service life, this research studies the effects of ocean wave loads on the strength of the platform’s structures. The response spectra of the platform obtained from model test in wave tank were used to verify the accuracy of the numerical model employed in this research. Eight wave load cases, which may affect the strength of the platform but not involved in the classification societies such as ABS and DNV, were newly considered in this research. The results of the research indicate that a) four of the eight newly added wave load cases are found to be greatly affecting the strength of the platform and need to be considered in designing the structures; b) torsional moment and shearing force caused by the ocean wave would cause the stress of the structures of platform at a high level and need to be carefully evaluated.

Analysis of changes in the survivability of building structures reinforced after an emergency dynamic impact in the context of assessing the security of buildings in the oil and gas industry

The relevance of the subject matter is conditioned by the technical complexity of the oil and gas facilities due to the increase in the volume and rate of raw materials production, which may be affected by shock-wave loads in emergency situations. The causes of the impact can be explosions, heavy cargo falls, terrorist attacks, natural and anthropogenic disasters, etc. These situations are very likely to cause significant damage to the building structures of industrial facilities, which necessitates their reinforcement. For further safe operation of the facility, reinforced structures must have survivability under repeated impacts no less than before the reinforcement. Given the fact that the survivability of buildings is a complex characteristic influenced by many factors, and it itself is a component of the security of a hazardous production facility, research in this area is topical. The purpose of the study is to test the developed method for assessing the survivability of a building structure under short-term shock-wave load based on the energy parameter and to analyze the results obtained in the context of assessing the security of critical oil and gas facilities. Research methods: Measurement of accelerations, deflections, and loads by strain measurement methods, graphoanalytical method of study using the Microsoft Excel software. A method for assessing the level of survivability of a building structure under shock-wave loading for critical oil and gas facilities using the survivability coefficient is developed. Using specific tests of conventional and cage-reinforced bending concrete elements for short-term dynamic load, the values of the specified coefficient are obtained. The values are compared and conclusions are drawn.

Influence of Mooring Tension on Dynamic Performance of Semi-submersible Wind Turbine under Typhoon Condition

A numerical model of a 5 MW semi-submersible wind turbine is established based on the reference wind turbine of American national renewable energy laboratory (NREL). The nominal diameter of the mooring chains was determined after the static wind load and wave load of the turbine under the action of typhoon being calculated by CFD method and Morison method. Finally, the dynamic responses of the turbine and the internal forces of the chains are obtained by the dynamic finite element analysis for three cases. The results show that when pretension chains are used, the turbine motion frequency is consistent with wave frequency, the surge is small, the pitch is reciprocally symmetrical, and the peak internal force of the chains is quite high. When mooring chains without pretension are adopted, the motion of the turbine consists of low-frequency drift and forced motion in sync with the wave frequency, the pitch is asymmetrical, and the internal tension force of the chains is relatively low.

THE BEHAVIOR OF THE SOIL UNDER FOUNDATION OF OFFSHORE GRAVITY STRUCTURES SUBJECTED TO DIFFERENT COMBINATION OF LOADS

This study aims at analyzing the behavioral rules of the soil under the bottom of the offshore gravity structures when it had been subjected to the combination of load types; in which the problem of determining the deformation of the ground in semi-infinite space is determined by the view of deformed solid mechanics and elastic theory. The ground plane displacement of the soil is simulated by the computer when the structural system is subjected to concentrated loads and the distribution load is consist of the eccentricity due to wave load and other horizontal loads.