LITERATURE REVIEW, MODELING AND ANALYSIS, MECHANICAL DESIGN & FABRICTION & TESTING CONSIDERATIONS OF LIQUID SPRING SHOCK ABSORBER

Abstract

Liquid spring based Shock Isolation system is a state of the art light weight suspension system which is used for heavy duty applications. This dissertation work deals with a liquid spring shock absorber in an application to isolate sensitive electronic instrumentation from shock loads in a defence problem. The fragility level of the equipment has been the motivating factor to use highly pressurized liquid spring for shock attenuation. In this report, the problem area with various design and analysis requirements & constraints are discussed in detail. The important considerations such as available space, bi-directional working, preloading arrangement and pressure limits are discussed in detail., On the basis of detailed literature review a shock isolation system based on the concept of Liquid spring is adopted for this application. Unlike normal hydraulic shock absorbers, Liquid spring works on the compressibility of the hydraulic oil. Keeping in view, the loads and space constraints a double acting, adjustable shock absorber is designed which uses silicone oil as the working medium. The construction and working of the proposed Shock absorber is discussed in detail. Mathematical formulation of the complete system is carried out considering the geometrical, hydraulic and mechanical parameters and using fundamental laws of mechanics. The various forces developed in the shock absorber are of complex non-linear nature and are very difficult to model and simulate. Still, on the basis of geometric construction, adopting various degrees of simplifications regarding fluid-dynamic phenomenon a mathematical model is developed to describe the non-linear phenomenon occurring within the shock absorber. The spring and damping characteristics depends upon the oil properties (v, j3, p) viz, viscosity, bulk modulus and density and the orifice parameters (1, do, N) viz. orifice length, diameter and number of orifices. The developed governing equation of the liquid spring is a second order ordinary differential equation. It is solved by numerical integration technique using MATLAB tool to obtain the plots of displacement, velocity and acceleration of the mass versus time. The purpose of the simulation is to study the systems responses and check them with the acceptable limits of displacement, acceleration and pressure...