Stochastic Modeling of Damage Physics for Mechanical Component Prognostics Using Condition Indicators

2009 ◽  
Author(s):  
David He ◽  
Ruoyu Li ◽  
Eric Bechhoefer
Keyword(s):  
Stochastic Modeling ◽  
Health Monitoring ◽  
Condition Indicators ◽  
Current Health ◽  
Modeling Methodology ◽  
Mechanical Component ◽  
Monitoring Applications ◽  
Deterioration Process ◽  
Physical Laws

The health of a mechanical component deteriorates over time and its service life is randomly distributed and can be modeled by a stochastic deterioration process. For most of the mechanical components, the deterioration process follows a certain physical laws and their mean life to failure can be determined approximately by these laws. However, it is not easy to apply these laws for mechanical component prognostics in current health monitoring applications. In this paper, a stochastic modeling methodology for mechanical component prognostics with condition indicators used in current health monitoring applications is presented. The effectiveness of the methodology is demonstrated with a real shaft fatigue life prediction case study.

scholarly journals Stochastic modeling and analysis of vapor cloud explosions domino effects in chemical plants

2019 ◽  
Vol 25 (1) ◽  
Author(s):  
Diego Sierra ◽  
Leonardo Montecchi ◽  
Ivan Mura
Keyword(s):  
Stochastic Modeling ◽  
Operating Conditions ◽  
Chemical Plants ◽  
Domino Effect ◽  
Modeling And Analysis ◽  
Modeling Methodology ◽  
Vapor Cloud ◽  
Maintenance Activities ◽  
Support Decision Making

Abstract Because of the substances they process and the conditions of operation, chemical plants are systems prone to the occurrence of undesirable and potentially dangerous events. Major accidents may occur when a triggering event produces a cascading accident that propagates to other units, a scenario known as domino effect. Assessing the probability of experiencing a domino effect and estimating the magnitude of its consequences is a complex task, as it depends on the nature of the substances being processed, the operating conditions, the failure proneness of equipment units, the execution of preventive maintenance activities, and of course the plant layout. In this work, we propose a stochastic modeling methodology to perform a probabilistic analysis of the likelihood of domino effects caused by propagating vapor cloud explosions. Our methodology combines mathematical models of the physical characteristics of the explosion, with stochastic state-based models representing the actual propagation among equipment units and the effect of maintenance activities. Altogether, the models allow predicting the likelihood of major events occurrence and the associated costs. A case study is analyzed, where various layouts of atmospheric gasoline tanks are assessed in terms of the predicted consequences of domino effects occurrence. The results of the analyses show that our approach can provide precious insights to support decision-making for safety and cost management.

Development of PZT fiber rosette to locate acoustic source

2021 ◽  
pp. 1045389X2199192
Author(s):  
Bao Chi Ha ◽  
Kevin Gilbert ◽  
Gang Wang
Keyword(s):  
Lead Zirconate Titanate ◽  
Health Monitoring ◽  
Lamb Wave ◽  
Lead Zirconate ◽  
Acoustic Source ◽  
Mechanical Coupling ◽  
Monitoring Applications ◽  
Commercial Off The Shelf ◽  
Lamb Wave Propagation ◽  
Strain Direction

Because of their electro-mechanical coupling property, Lead-Zirconate-Titanate (PZT) materials have been widely used for ultrasonic wave sensing and actuation in structural health monitoring applications. In this paper, a PZT rosette concept is proposed to conduct Lamb wave-based damage detection in panel-like structures by exploring its best directional sensing capability. First, a directivity study was conducted to investigate sensing of flexural Lamb wave propagation using a PZT fiber having d33 effects. Then, commercial off-the-shelf PZT fibers were polarized in-house in order to construct the PZT rosette configuration, in which three PZT fibers are oriented at 0°, 45°, 90°, respectively. Since Lamb wave responses are directly related to measured PZT fiber voltage signals, a simple interrogation scheme was developed to calculate principal strain direction in order to locate an acoustic source. Comprehensive tests were conducted to evaluate the performance of the proposed PZT rosette using an aluminum plate. It is shown that the PZT rosette is able to sense Lamb wave responses and accurately locate an acoustic source. We expect to further evaluate the PZT rosette performance when damages are introduced.

scholarly journals Hybrid Carbon Microfibers-Graphite Fillers for Piezoresistive Cementitious Composites

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 518
Author(s):  
Hasan Borke Birgin ◽  
Antonella D’Alessandro ◽  
Simon Laflamme ◽  
Filippo Ubertini
Keyword(s):  
Percolation Threshold ◽  
Health Monitoring ◽  
Cementitious Materials ◽  
Strain Sensing ◽  
Composite Matrix ◽  
Hybrid Fillers ◽  
Monitoring Applications ◽  
Conductive Fillers ◽  
Carbon Microfibers ◽  
Hybrid Carbon

Multifunctional structural materials are very promising in the field of engineering. Particularly, their strain sensing ability draws much attention for structural health monitoring applications. Generally, strain sensing materials are produced by adding a certain amount of conductive fillers, around the so-called “percolation threshold”, to the cement or composite matrix. Recently, graphite has been found to be a suitable filler for strain sensing. However, graphite requires high amounts of doping to reach percolation threshold. In order to decrease the amount of inclusions, this paper proposes cementitious materials doped with new hybrid carbon inclusions, i.e., graphite and carbon microfibers. Carbon microfibers having higher aspect ratio than graphite accelerate the percolation threshold of the graphite particles without incurring into dispersion issues. The resistivity and strain sensitivity of different fibers’ compositions are investigated. The electromechanical tests reveal that, when combined, carbon microfibers and graphite hybrid fillers reach to percolation faster and exhibit higher gauge factors and enhanced linearity.

A methodology for resiliency assessment of existing bridges – a study on a bridge from 1930

2021 ◽  
Author(s):  
Guy L. Larose ◽  
Pierre-Olivier Dallaire ◽  
Theresa Erskine ◽  
Chiara Pozzuoli ◽  
Emanuele Mattiello
Keyword(s):  
Hazard Assessment ◽  
Health Monitoring ◽  
Ad Hoc ◽  
Rehabilitation Program ◽  
Wind Loading ◽  
Close Collaboration ◽  
Current State ◽  
Design Life ◽  
Existing Bridges

<p>This paper introduces the methodology RWDI has developed, tested and consolidated over the years working in close collaboration with bridge designers, owners and operators, for the multi-hazard assessment of existing bridges and the ad hoc development of a structural health monitoring programme leading to enhanced resiliency. The work is highlighted through the presentation of a case study for a 2,725 m long cantilever bridge built in 1930. The dynamics of the structure in its current state were characterised and its capacity to today and future wind loading was assessed fully following the proposed methodology prior to the initiation of a structural rehabilitation program to extend the design life of the bridge beyond its 150th anniversary.</p>

scholarly journals Energy Efficiency of Fog Computing Health Monitoring Applications

2018 ◽  
Author(s):  
Ida Syafiza M. Isa ◽  
Mohamed O. I. Musa ◽  
Taisir E. H. El-Gorashi ◽  
Ahmed Q. Lawey ◽  
Jaafar M. H. Elmirghani
Keyword(s):  
Energy Efficiency ◽  
Health Monitoring ◽  
Fog Computing ◽  
Monitoring Applications
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