Preventive Replacement Policies with Aging Failure and Third-part Damage

2016 ◽  
Author(s):  
Xufeng Zhao ◽  
Khalifa N. Al-Khalifa ◽  
Abdel Magid Hamouda
Keyword(s):  
Preventive Replacement

A weak derivative approach to optimization of threshold parameters in a multicomponent maintenance system

2001 ◽  
Vol 38 (02) ◽  
pp. 386-406 ◽  
Author(s):  
Bernd Heidergott
Keyword(s):  
Optimization Problems ◽  
Estimation Algorithm ◽  
Replacement Policy ◽  
Cost Performance ◽  
Weak Derivative ◽  
Preventive Replacement ◽  
Maintenance System ◽  
Threshold Optimization ◽  
Age Replacement ◽  
The Cost

We consider a multicomponent maintenance system controlled by an age replacement policy: when one of the components fails, it is immediately replaced; all components older than a threshold age θ are preventively replaced. Costs are associated with each maintenance action, such as replacement after failure or preventive replacement. We derive a weak derivative estimator for the derivative of the cost performance with respect to θ. The technique is quite general and can be applied to many other threshold optimization problems in maintenance. The estimator is easy to implement and considerably increases the efficiency of a Robbins-Monro type of stochastic approximation algorithm. The paper is self-contained in the sense that it includes a proof of the correctness of the weak derivative estimation algorithm.

Optimal repair/replacement policy for a general repair model

2001 ◽  
Vol 33 (1) ◽  
pp. 206-222 ◽  
Author(s):  
Xiaoyue Jiang ◽  
Viliam Makis ◽  
Andrew K. S. Jardine
Keyword(s):  
Average Cost ◽  
Failure Time ◽  
Operating Time ◽  
Replacement Policy ◽  
Repair Cost ◽  
Virtual Age ◽  
Preventive Replacement ◽  
Long Run ◽  
Special Cases ◽  
Cost Limit

In this paper, we study a maintenance model with general repair and two types of replacement: failure and preventive replacement. When the system fails a decision is made whether to replace or repair it. The repair degree that affects the virtual age of the system is assumed to be a random function of the repair-cost and the virtual age at failure time. The system can be preventively replaced at any time before failure. The objective is to find the repair/replacement policy minimizing the long-run expected average cost per unit time. It is shown that a generalized repair-cost-limit policy is optimal and the preventive replacement time depends on the virtual age of the system and on the length of the operating time since the last repair. Computational procedures for finding the optimal repair-cost limit and the optimal average cost are developed. This model includes many well-known models as special cases and the approach provides a unified treatment of a wide class of maintenance models.

Preventive replacement policies for parallel systems with deviation costs between replacement and failure

2020 ◽  
Author(s):  
Xufeng Zhao ◽  
Satoshi Mizutani ◽  
Mingchih Chen ◽  
Toshio Nakagawa
Keyword(s):  
Parallel Systems ◽  
Preventive Replacement

scholarly journals A FEA-Based Methodology to Predict the Osteotome Wear Status during Nasal Bone Surgical Operations

Coatings ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 855 ◽  
Author(s):  
G. Skordaris ◽  
F. Stergioudi ◽  
A. Boumpakis ◽  
D. Stergioudi ◽  
H. Behrbohm
Keyword(s):  
Fatigue Strength ◽  
Nasal Bone ◽  
Bone Geometry ◽  
Test Results ◽  
Surgical Instrument ◽  
Preventive Replacement ◽  
Fea Model ◽  
Von Mises ◽  
Von Mises Stresses ◽  
Surgical Operations

A FEA-based methodology was developed in order to predict the wear status of an osteotome (surgical instrument) during its use in a lateral nasal bone osteotomy considering its fatigue strength. The latter parameter was determined by appropriate FEM-evaluation of the perpendicular impact test results. For the simulation of the surgical procedure, two scenarios were examined: (i) when utilizing a brand new osteotome and (ii) when utilizing an already used osteotome characterized by decreased fatigue strength. The actual nasal bone geometry used in the FEA model was obtained from a high-resolution, maxillofacial, computed tomography (CT) scan of a single patient. In both cases examined, depiction of fracture patterns for the osteotome and the nasal bone were obtained. The wear of a new osteotome and an already used osteotome was also calculated and compared. The developed von Mises stresses in both the osteotome and nasal bone were depicted. The proposed methodology allowed an accurate prediction of the critical number of impacts that the osteotome can receive during the lateral nasal osteotomy which is followed in all rhinoplasties. Based on the developed methodology, a preventive replacement of the osteotome before its extensive fracture can be determined, thereby minimizing the risk of postoperative complications.

Optimal preventive replacement policy for homogeneous cold standby systems with reusable elements

2020 ◽  
Vol 204 ◽  
pp. 107135 ◽  
Author(s):  
Gregory Levitin ◽  
Maxim Finkelstein ◽  
Yuanshun Dai
Keyword(s):  
Replacement Policy ◽  
Preventive Replacement ◽  
Cold Standby

Decision and Optimization for Preventive Replacement Contents of Ship Equipment with Multistate System

2015 ◽  
Vol 741 ◽  
pp. 594-598
Author(s):  
Jia Liu ◽  
Jian Wei Lv ◽  
Jing Bo Yan
Keyword(s):  
Heuristic Algorithm ◽  
Pareto Optimality ◽  
Case Analysis ◽  
Replacement Cost ◽  
Preventive Replacement ◽  
Optimality Model ◽  
Multistate System ◽  
Replacement Time

To scientifically analyze the preventive replacement contents of ship equipment with multiple performance states during sea service, this paper builds a Pareto optimality model for replacement contents based on mission reliability, replacement time and replacement cost, brings forward a heuristic algorithm to constantly eliminate non-inferior solution and impossible solution, and presents a case analysis to verify accuracy of model and operability of algorithm.

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