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Hard disk drives (HDDs) are sensitive devices responsible for storing and retrieving digital information in computer systems and electronic products. In particular, HDDs of laptop personal computers (LPCs) are very sensitive especially in harsh mechanical environments. Accordingly, it is necessary to protect them against damages attributable to shock and vibration so as to reach better magnetic read/write performance. In this paper, the nonlinear multi-objective optimization method is utilized to enhance the passive control performance of rubbers through minimizing destructive effects of shock and random excitations. As a matter of fact, this investigation will focus on improving the shock and vibration isolation system with special emphasis on the role of rubber feet. A zero mean, stationary process with Gaussian distribution is applied to the base in order to consider effects of random excitation. Moreover, a half-sine pulse of acceleration is assumed as the base shock excitation. According to limitations of geometrical parameters and lumped modal parameters, twelve inequality constraints are presented. Modal parameters of rubber mounts and rubber feet are selected as design variables of optimization, and the multi-objective optimization problem is solved for three commercial cases of HDD by using non-dominated sorting genetic algorithm II (NSGA-II), which was proposed based on Pareto-optimality concept. Therefore, new characteristics of rubber mounts and rubber feet are recommended to be manufactured for the purpose of protecting HDDs against shock and random excitations. [ABSTRACT FROM AUTHOR]

Hard disk drives (HDDs) of laptop personal computers (LPCs) are devices vulnerable in harsh mechanical environments. Hence, they need to be protected against damages due to vibration in order to have better read/write performance. In the present study, a LPC and its HDD are modeled as a system with two degrees of freedom and the nonlinear optimization method is employed to perform a passive control through minimizing the root mean square of HDD absolute acceleration due to a base random excitation. The presented random excitation is considered as a stationary, zero mean process with Gaussian distribution. In addition, eleven inequality constraints are defined based on geometrical limitations and allowable intervals of lumped modal parameters. The target of the optimization is to obtain optimum modal parameters of rubber mounts and rubber feet as design variables and subsequently propose new characteristics of rubber mounts and rubber feet to be manufactured for HDD protection against random excitation. In this paper, a nonlinear optimization problem is separately solved for three widely-used cases of HDD by using modified constrained steepest descent algorithm (PLBA) which was extended based on sequential quadratic programming. Finally, the genetic algorithm is used to verify results of the PLBA algorithm. [ABSTRACT FROM AUTHOR]