Experimental investigation of damping characteristics of sandwiched engine isolators using two-way isolator excitation method (TWIEM) and performance evaluation

Dynamic properties of engine isolators are of significant importance in determining the performance of the isolator and precise prediction of the dynamic behavior at the design stage. Unfortunately, the damping property can not be deduced deterministically from other structural properties because it is highly dependent on dynamic shear properties such as frequency and temperature of material under application. Generally damping properties are determined from experiments conducted on the desired setup. Many times, designers use the damping property data available in literature. Such data may not be recommended for development of predictive models for dynamic behavior. This paper presents a novel method of determination of damping property of the engine isolator. The method is called two-way isolator excitation method (TWIEM). The damping property is determined by excitation of the isolator for active and passive transmissibility. The purpose of this paper is to analyze the vibration isolation by checking the transmissibility ratio for various engine isolators. Sandwiched engine isolators are designed to blend the good properties of different isolation materials to make it more efficient. The experimentation was carried out using three different isolator designs and compared the performance of the isolator on the basis of isolation percentage. Mild steel plates, polymer foam sheets and natural rubber materials are used as Isolator materials. The results show that low damping ratio isolating material is more effective in isolating the vibration source.