Dynamic Analysis of Free-standing Equipment under Blast Shock

Abstract

Analysis of the motion state of the free-standing equipment under blast shock and vibration has important guiding significance for the safety of the equipment. In this paper, the model of shaking motion of the free-standing equipment under blast shock was established, and the governing equations of shaking motion of the free-standing equipment were derived. The semi-sinusoidal pulse recommended by the specification was used to describe the motion waveform of the explosion blast location. Analytical calculation method was used to solve shaking motion governing equations of the free-standing equipment under the impact of horizontal shock. Numerical calculation method was used to analyze the motion governing equations of the free-standing equipment under the coupling effect of horizontal shock and vertical shock. The factors affecting the toppling of the free-standing equipment were analyzed. Introduction There has been a great increase in advanced equipment adopted in teaching, research, production and other fields in China, such as precision machinery, instruments and apparatus, regulator, checkout and detection equipment, etc. Many of these devices, which are not fixed to the foundation but are placed directly on the table rest or on the ground, are called free-standing equipment. When nuclear explosion and conventional weapon explosion reacting, it will cause strong impact and vibration of the surrounding medium and engineering structure of the protection project, thus cause the free-standing equipment inside the project to slide, shake or even topple over, which will cause damage to the equipment and loss of corresponding functions. Therefore, the study of the motion characteristics of the free-standing equipment on the basis of motion and the determination of the factors affecting the toppling of the free-standing equipment are of great guiding significance for the safe work, safekeeping, updated design of the isolation and anti-seismic of the free-standing equipment. Basic Assumption The motion of the free-standing equipment on dynamic foundation is very complicated. In this paper, the free-standing equipment was assumed as a homogeneous rigid body and the ground was assumed as a rigid plane to simplify the analysis. The model adopted is shown in Figure 1: is equipment shape angel and θ is equipment shaking angle. The engineering structure vibrated under impact and vibration result in the foundation of the free-standing equipment vibrated. When the movement increased to a certain extent, the free-standing equipment will shake or slide or even slide and shake. Due to the space limitation, only pure shaking motion was studied in this paper.