A. H. Shirmohammadi,
Volume 19, Issue 2 (1-2001)
Abstract
The present study is intended to develop a Preventive Maintenance (PM) policy for industrial applications, while considering two different objectives: the first objective is to optimize the total maintenance costs, i.e., the Preventive Maintenance (PM) and Emergency Maintenance (EM) Costs Per Unit Time. (CPUT). The second objective is to design the policy in such a way that the simplicity of its application in a production industry environment is improved.
A simulation model is constructed and, using a Monte Carlo simulation, the model is run for a sufficient number of cycles in order to determine the optimum value of a decision parameter (TX). The TX value provides the PM planning section with the possibility of economically postponing the PM action to its next scheduled date. Numerical examples are given to show the validity of the model and comparisons are made with existing PM policies in industry and in the literature to evaluate the cost reduction values that can be obtained through the adoption of the policy, while the implementation simplicity is also maintained
F. Shirmohammadi, M. M. Saadatpour,
Volume 37, Issue 1 (9-2018)
Abstract
In this article spectral modal method is developed for studying wave propagation in thin plates with constant or variable thickness. Theses plates are subjected to the impact forces and different boundary conditions. Spectral modal method can be considered as the combination of Dynamic Stiffness Method (DSM), Fourier Analysis Method (FAM) and Finite Stripe Method (FSM). Using modeling of continuous distribution of mass and an exact stiffness causes solutions in frequency domain. Unlike the most numerical methods, in this method refining meshes is no longer necessary in which the cost and computational time is decreased. In this paper the important parameters of the method and their effects on results are studied through different examples.
