DYNAMIC ANALYSIS OF EQUIPMENT WITH MOTION LIMITING DEVICES

Abstract

Equipments are often mounted on resilient support so as to minimize the transmission of mechanical vibration to the structure. In most of the equipments large longitu-dinal and small transverse movement due to thermal stresses is provided. Large transverse displacement due to seismic forces is not permitted due to other constraints. Therefore to arrest the large transverse movement of the equipment motion limiting devices are often used. In this work an attempt has been made to study the dynamic behaviour of equipment with motion limiting devices, which envisage mathematical idealisation of the problem, formulation of equation of motion and to identify the para-meters of the devices which significantly affect the behaviour of the equipment and the ,sensitivity of these parameters have been studied here. A solution algorithm employing contact and release of the two masses (i.e. of equipment and the device) condition has been developed. Computer code LRSDF & NRSDF has also been developed for the dynamic analysis of equipment implementing the above procedure. The curves between various parameters of the device and equipment -response (displacement & acceleration) has been plotted. Finally these curves will be utilised to decide the stiffness of the motion limiting device given the gap spacing ratio and equipment dynamic properties