Residual Life Prediction Method Research Articles

Research on Residual Life Prediction for Electrical Connectors Based on Intermittent Failure and Hidden Semi-Markov Model

Based on the dynamic properties of electrical connector intermittent failure, the model and methods for residual life prediction for electrical connectors are studied in this paper. Firstly, the mechanism of electrical connector intermittent failure is analyzed, and the area enclosed by the contact resistance curve and the fault threshold is defined as the generalized severity of intermittent failure to describe how severe the electrical connector’s intermittent failure is. Then, the Hidden Semi-Markov Model (HSMM) is introduced to build the residual life prediction model of the electrical connector. Further, the evaluation method of using the state and prediction method for residual life are studied. Finally, by carrying out the residual life prediction test, the effectiveness of the residual life prediction method for electrical connectors based on intermittent failure and HSMM is verified.

A New Residual Life Prediction Method for Complex Systems Based on Wiener Process and Evidential Reasoning

A new residual life prediction method for complex systems based on Wiener process and evidential reasoning is proposed to predict the residual life of complex systems effectively. Moreover, the better maintenance strategies and decision supports are provided. For the residual life prediction of complex systems, the maximum likelihood method is adopted to estimate the drift coefficient, and the Bayesian method is adopted to update the parameters of Wiener process. The process of parameters estimation and the probability density function (PDF) of the residual life are deduced. To improve the accuracy of the residual life prediction results, the evidential reasoning (ER) is used to integrate the prediction results of Wiener process. Finally, a case study of gyroscope is examined to illustrate the feasibility and effectiveness of the proposed method, compared with fuzzy theory, which provides an important reference for the optimization of the reliability of complex systems and improvement.

Residual Service Life Prediction for Bridges Based on Critical Life Curves

AbstractA residual service life prediction method based on critical life curves of selected bridge members is presented in this paper for bridges in service. The lowest target reliability index is ...

Service fatigue life and service calendar life limits of aircraft structure: aircraft structural life envelope

ABSTRACTThe service life of aircraft structure includes the fatigue life and calendar life. The Aircraft Structural Life Envelop (ASLE) is a safe and reliable life scope of aircraft structures in service. The specific steps to establish the ASLE are developed, and a residual life prediction method for aircraft structure under service environments is established by combining the ASLE with the Miner theory. Furthermore, a service life extension method of aircraft structure is proposed based on a scope extension of the ASLE, including methods based on reliability analysis and structural repair. Finally, an application example of the ASLE is presented.

Residual life prediction based on dynamic weighted Markov model and particle filtering

In order to improve the prediction accuracy of non-Gaussian data and build reasonably the prediction model, a novel residual life prediction method is proposed. A dynamic weighted Markov model is constructed by real time data and historical data, and the residual life is predicted by particle filter. The particles of the state vector are predicted and updated instantaneously using particle filter. The probability distribution of the predicted value is estimated by the updated particles. The residual life can be predicted using the set threshold of the state. This method improves the accuracy of residual life prediction. Finally, the advantage of this proposed method was shown experimentally using the bearings’ full cycle data.

Recovery of Fatigue Damage and Life Prediction by Laser Irradiation Healing Treatment for Copper Film

A fatigue life prediction method was investigated after healing fatigue damage by excimer laser irradiation treatment for the damaged copper film. First, the variations of residual fatigue life and strain range for the damaged specimens after laser irradiation healing treatment were analyzed. The results showed that the fatigue damage can be effectively healed by laser irradiation for copper film. The presented healing phenomenon during laser irradiation process showed that the recovery of fatigue damage can result in the improvement in fatigue life for the damaged copper film. Then, based on the fact that the strain concentration factor of copper film had not been changed before and after laser irradiation treatment, a residual fatigue life prediction method was proposed by the local stress transformation. The predicted residual fatigue lives by the proposed method agreed well with the experimental results for copper film after laser irradiation treatment.

Equivalent damage-healing approach to residual fatigue life prediction for copper film by laser repair

A healing method for fatigue damage was investigated by laser shock peening and laser irradiation with excimer laser for polycrystalline copper film. It is found that the sum of the consumed fatigue ductility and the total fatigue ductility for the damaged specimen after both laser treatments is equal to the total fatigue ductility for the undamaged specimen after both laser treatments. The evolution of the damage healing can be replaced by that for the undamaged specimen after laser treatment. Based on the equivalent fatigue damage evolution, a residual fatigue life prediction method is proposed during the damage-healing process for the copper specimen. The predicted lives by the proposed method agree well with the experimental results.

A Study of Gearbox Residual Life Prediction Method Based on Stochastic Filtering and Recursive Expectation Maximization Model

Residual life prediction is a critical and difficult problem in condition-based maintenance decision-making. Aiming to deal with the problems that practical data is limited and the estimation of initial parameters is not accurate in maintenance practice, a residual life prediction method for gearbox based on stochastic filtering (SF) is proposed. In this method, recursive expectation maximization (REM) algorithm is introduced to update the parameters, and a maximum likelihood estimation method is designed to update the unknown parameters. Finally, the validity and practicability of the model are validated by an example.

Residual Life Prediction of Rotating Equipment in Thermal Power Plants Using Online Estimation with Forgetting Factor

SUMMARYIn this paper, an online deterioration prediction and residual life prediction method is proposed for maintenance of rotating equipment in thermal power plants. The condition of rotating equipment is inspected by vibration measurement. A mathematical model for the deterioration of the rotating equipment is derived in order to predict the future condition of the rotating equipment. The residual life of the rotating equipment is predicted by deterioration prediction using online estimation of the model parameters with a forgetting factor. The effectiveness of the residual life prediction method is assured by applying it to actual vibration data of rotating equipment.

Residual life prediction for healing fatigue damaged copper film by laser shock peening

ABSTRACTA healing method for fatigue damage was studied by laser shock peening (LSP) with excimer laser for polycrystalline copper film. It is found that work hardening due to LSP could be responsible for the improvement of residual fatigue lives for the damaged and undamaged specimens by LSP, and the hardening degree for the damaged specimen by LSP is obviously higher than that for the undamaged specimen by LSP. In this paper, two basic mechanisms were identified. One is the dissipated energy enhancement mechanism, which improves the fatigue life caused by laser shock stress, and the other is the healing mechanism, which leads to a further improvement. Based on the two mechanisms, a residual fatigue life prediction method is proposed by the view of energy consumption before and after LSP. The predicted lives by the proposed method agree well with the experimental results.

Sustainment Engineering and Residual Life Prediction of Aluminum Alloy Structure at Service Environment

The effects of service environment will cause corrosion damage and fatigue cracks to initiate and grow, compromising structural integrity of the aircraft aluminum alloy structure. To develop an effective inspection and maintenance-scheduling program that takes advantage of life extension technologies, the sustainment engineering and residual life prediction method of aging aircraft aluminum alloy structure at service environment was proposed in this article. The whole algorithm of the sustainment engineering was described and the included situations of repairs, corrosion damage and widespread fatigue damage on aircraft structures were presented. At last, combining the results of FEM calculation with the AFGROW software of crack growth analyses, the residual life of corroded aluminum alloy structure was estimated.

Toward effective utilization of similarity based residual life prediction methods: Weight allocation, prediction robustness, and prediction uncertainty

Similarity based residual life prediction method is an emerging method for component residual life prediction. Studies on (a) the effect of weight function on prediction accuracy; (b) prediction robustness; and (c) prediction uncertainty of such method are rare. However, the abovementioned factors are essential concerns for wide application of a similarity based residual life prediction method. In this article, the essential elements of a similarity based residual life prediction method is outlined first with an extended weight function introduced. Afterward, an evaluation framework for investigating the prediction robustness of a similarity based residual life prediction method is established. In addition, a prediction uncertainty estimation method is proposed based on historical samples, inspired by cross-validation technique. In an extensive numerical investigation, a comparative study on the effect of weight function on prediction accuracy is conducted by tuning the parameters in the weight function. The prediction robustness of the similarity based residual life prediction method is evaluated in comparison with a time-series forecasting based residual life prediction method. Finally, the proposed prediction uncertainty estimation method is illustrated, which may facilitate further application of the similarity based residual life prediction method.

Residual Life Prediction of Rotating Equipment in Thermal Power Plants Using On-line Estimation with Forgetting Factor

In this paper, an on-line deterioration prediction and residual life prediction method is proposed for maintenance of rotating equipment in thermal power plants. Condition of rotating equipment is inspected by vibration measurement. A mathematical model for the deterioration of the rotating equipment is derived in order to predict future condition of the rotating equipment. Residual life of the rotating equipment is predicted by deterioration prediction using on-line estimation of model parameters with forgetting factor. The effectiveness of the residual life prediction method is assured by applying it to actual vibration data of rotating equipment.

Effects of low-cycle fatigue on static mechanical properties, microstructures and fracture behavior of 304 stainless steel

A series of experiments, including constant amplitude low-cycle fatigue tests, post-fatigue tension to failure tests, LOM (TEM) observations, and SEM examinations, were performed at room-temperature to investigate the effects of low-cycle fatigue damage on the static mechanical properties, microstructures and fracture behavior of 304 austenitic stainless steel. The changing characteristics of various static mechanical property parameters, including the strength parameters ( σ ys and σ ult), stiffness parameter ( E), ductility parameters ( δ and φ f ) and strain hardening exponent ( n) during fatigue damage process of the stainless steel were obtained experimentally and their micromechanisms were discussed by analyzing both the deformation microstructures and the fracture features of cyclically pre-deformed specimens. It was shown that the austenite/martensite transformation resulting from the accumulation of cyclic plastic strain was mostly responsible for the variation in the strength, ductility and strain hardening ability of the stainless steel during fatigue damage process. The depletion of the inherent ductility in the material due to fatigue damage evolution led to the ductile-to-brittle transition (DBT) in the fracture modes. Based on the macro/micro-experiments regarding the exhaustion of the ductility during fatigue damage, the ductility parameter was suggested as a damage indicating parameter for the present stainless steel in further studying the fatigue damage mechanics model as well as the residual fatigue life prediction method.

Prediction method of corrosion fatigue crack initiation life based on corrosion pit growth mechanism.

Corrosion fatigue crack initiation behavior of low alloy steel has been investigated in water. It was observed that corrosion fatigue process was composed of three stages, namely, corrosion pit growth, transition into crack from the corrosion pit and corrosion fatigue crack propagation. The corrosion pit size was found to increase with time t following the relation : corrosion pit size ∝ t1/3. The condition of transition into crack from the corrosion pit was determined by a stress intensity factor, by assuming the corrosion pit as a sharp crack. The critical pit condition (ΔK)p was 1.2 MPa √(m) for 2.5 NiCrMoV and 3.5 NiCrMoV in 90°C water with 100 ppb dissolved oxygen. Based on the abovementioned results, residual life prediction method for corrosion fatigue crack initiation was proposed.