Robust design studies for vibration and shock isolation of sensitive electronic equipments

Robust design methodology is concerned with the process and the product design while minimizing the effects of uncertainties in design and external noises. In robust design, optimum system design is sought with special emphasis on the insensitiveness of objective functions due to uncertainties. This study focuses on the robust design studies of vibration and shock isolation of sensitive electronic equipment. The performance of three types of isolators due to vibration and shock loading is analyzed. The methodology is based on minimizing the Root Mean Square (RMS) of the linear and angular vibrations and the Square Root of Sum of Squares (SRSS) of shock response. The variations for the inertial properties of the equipment, the material properties of viscoelastic isolators and the isolator locations with respect to the equipment mass center are considered as the noise variables. The electronic equipment to be isolated are modeled as a rigid body having 6 degrees of freedom. Signal to Noise (S/N) ratios of the linear acceleration and the angular velocity responses due to vibration loading, along with the (S/N) ratios of the linear acceleration and linear displacement responses due to shock loading are defined. The first order tolerance analysis is also performed to assess the sensitivities of responses to noise variables to determine the key variables for which the variations are to be reduced.