scholarly journals A Review on Residual Life Assessment of Plain and Reinforced Concrete Members

2021 ◽  
Author(s):  
Ajimi S ◽  
Keerthy M Simon ◽  
Bharati Raj
Keyword(s):  
Reinforced Concrete ◽  
Residual Life ◽  
Process Zone ◽  
Maximum Amplitude ◽  
Fatigue Loading ◽  
Life Assessment ◽  
Moment Capacity ◽  
Strength Assessment ◽  
Fibre Bridging ◽  
Tension Softening

Under fatigue loading, concrete like quasi-brittle materials exhibit softening behaviour since an inelastic zone will be formed in front of the crack tip called the fracture process zone (FPZ). There are various toughening mechanisms that exhibiting in this region. Current design practices for reinforced concrete assumes a zero tensile strength for concrete which is actually overly conservative. In fact, concrete can bear significant tensile stress and strain. Therefore, the tension softening response of RC member should consider in the study. Under fatigue loading, strength and stiffness decrease progressively according to the maximum amplitude and the number of cycles of loading. Fracture plays an important role in failure of normally and lightly reinforced beam. Since FPZ mechanisms and fibre bridging action resist crack propagation, we have to consider these mechanisms while assessing remaining life of RC member. Fatigue failure occurs when applied load is much less than the moment capacity. Such structures susceptible to fatigue load need to be monitored and residual life is to be predicted. This paper is presenting a review on the residual strength assessment on plain and reinforced concrete. The review includes the influence of various tension-softening models in predicting the residual life of plain and reinforced concrete. A comparative study is also conducted in order to assess the residual life by considering various tension softening laws.

Assessment of the Effect of Pitting Corrosion on Fatigue Crack Initiation in Hydro Turbine Shaft

2013 ◽  
Vol 633 ◽  
pp. 186-196 ◽  
Author(s):  
Radivoje Mitrovic ◽  
Dejan Momcilovic ◽  
Ivana Atanasovska
Keyword(s):  
Pitting Corrosion ◽  
Fatigue Crack Initiation ◽  
Fatigue Loading ◽  
Critical Distance ◽  
Life Assessment ◽  
Stress Concentrations ◽  
Hydro Power ◽  
Turbine Shaft ◽  
Improved Design ◽  
Material Length

Energy efficiency is a key issue worldwide, and not confined solely to the realm of engineers. Past failures of mechanical power system components must be examined carefully in order to minimise future occurrences and increase energy efficiencies. Improved design procedures have been highly sought by engineers and researchers over the past few decades. The latest verified method with strong application potential within the power industry is that of the Theory of Critical Distances (TCD). TCD is not one method, but a group of methods that have a common feature; the use of a characteristic material length parameter, the critical distance L, for calculating the influence of notch-like stress raisers under static and fatigue loading. A case study from a hydro power plant turbine shaft was chosen to illustrate the development of this methodology. The paper illustrates the application of TCD to the fatigue life assessment of a turbine shaft with stress concentrations due to pitting corrosion.

Evaluation of Residual Life of Existing Offshore Platforms in Western Offshore, India

2021 ◽  
Author(s):  
A. Renugadevi ◽  
S. Nallayarasu ◽  
S. Karunanithi
Keyword(s):  
Residual Life ◽  
Probability Of Failure ◽  
Oil Field ◽  
Life Extension ◽  
Offshore Platforms ◽  
Strength Assessment ◽  
Encounter Probability ◽  
Reliability Method ◽  
Reserve Strength ◽  
Extension Period

Abstract Western offshore oil field in India has nearly 300 offshore platforms for oil and gas exploration, of which almost 50% of platforms have outlived their life. Life extension of these platforms has become essential for further production activities. In many cases, design level analyses combined with ultimate strength assessment, life extension has been granted. However, risk-based assessment based on the probability of failure based on available reserve strength linked to additional life extension could be a logical method. The Reserve Strength Ratio (RSR) is defined as a ratio of reserve capacity of the jacket structure and the design level environmental loads (1 year or 5year or 10 year or 100-year return period). The encounter probability of these design storms for the life extension period has been established probability for the extension period has been used as a threshold to determining the required RSR using the probability of collapse. For the present study, four typical aged wellhead platforms with different water depths are selected, and RSR is evaluated by carrying out push over analysis. The Monte Carlo Simulation method is used to generate the statistical values of RSR. The probability of failure is then calculated by First Order Reliability Method (FORM) using MATLAB for different RSR values. Reassessment criteria for the existing offshore platforms have been described from the reliability analysis results based on probability failure and encounter probability.

Residual service life estimation of bridges

2021 ◽  
Author(s):  
Mayank Bajaj ◽  
Biswajit Bhattacharjee
Keyword(s):  
Residual Life ◽  
Concrete Bridges ◽  
Life Assessment ◽  
Residual Service Life ◽  
Chloride Ingress ◽  
Service Life Estimation ◽  
Residual Life Assessment ◽  
Existing Bridges ◽  
Residual Service

<p>While concrete structures perform well in many situations, lack of durability has emerged as a significant issue for asset owners. A review of past bridge failures was done to identify the most probable causes of bridge failures. This study has tended to focus on current models used for estimating the time to deterioration of concrete bridges instigated by Chloride ingress and Fatigue. Subsequently, mathematical modelling of the best-suited deterioration model is done to arrive at the residual life of two existing bridges. This work has highlighted high variability in the parameters used to describe the durability related properties of in-situ aged concrete. A realistic residual life assessment can be achieved by correct evaluation of these parameters by periodic testing of bridge samples</p>

Criterial relationships for residual life assessment of materials

2006 ◽  
Vol 38 (4) ◽  
pp. 348-353 ◽  
Author(s):  
A. A. Lebedev ◽  
V. M. Mikhalevich
Keyword(s):  
Residual Life ◽  
Life Assessment ◽  
Residual Life Assessment

scholarly journals Study on Life Model of MOV Based on Multiple Parameters and Surge History

2021 ◽  
Author(s):  
RUAN Xiaofei ◽  
Shaoyun JIN ◽  
WEN Weigang ◽  
CHENG Weidong
Keyword(s):  
Life Prediction ◽  
Residual Life ◽  
Cumulative Effect ◽  
Degradation Process ◽  
Life Assessment ◽  
Lightning Protection ◽  
Multiple Parameters ◽  
History Information ◽  
Life Model ◽  
Metal Oxide Varistor

Abstract With the advance of intelligent operation and maintenance in china railways, the requirement of condition monitoring and remaining life prediction for lightning protection equipment has become increasingly urgent. MOV(Metal Oxide Varistor) is the key component of railway surge protector, and it is necessary to study the description model of its degradation process. The output of the model that uses a single parameter to characterize degradation is more prone to contingency, and cannot truly and fully reflect the life state of the MOV. The degradation of MOV is a cumulative effect, and its life model should consider the surge history information. In view of the above problems, a prediction model of the residual life value of MOV is given by combining various degradation related parameters and surge history. Firstly, nine degradation related parameters are fused to construct degradation core. Then, the degradation core and surge history are fused through Markov chain to build a life model of MOV. Then, the model is calibrated with experimental data. Finally, the model is validated and analyzed by experiments. The model can describe the degradation process of MOV more comprehensively and accurately, and can predict the residual life value at the same time, and it has potential application in the life assessment of surge protective devices.

Residual Life Assessment for Boiler Pressure Components Based on Measurements of Creep Strains

1988 ◽  
Vol 110 (3) ◽  
pp. 308-313 ◽  
Author(s):  
F. Mlynarski ◽  
J. Taler
Keyword(s):  
Residual Life ◽  
Life Assessment ◽  
Strain Measurements ◽  
Years Of Service ◽  
Residual Life Assessment ◽  
Outside Diameter ◽  
Creep Strains

This paper discusses different methods for calculating the residual life for boiler pressure components operating under creep conditions, based on tube outside diameter strain measurements. These measurements were made for over 20 yr. The methods have been applied to the residual life calculation for pipelines of 20 or more years of service. Then the results have been compared.

Sign in / Sign up

Export Citation Format

Share Document