Service Life Evaluation of Fleet of Municipal Trains

2012 ◽  
Author(s):  
Przemyslaw Rakoczy ◽  
Cory J. Hogan
Keyword(s):  
Service Life ◽  
Time History ◽  
Operating Conditions ◽  
Life Extension ◽  
Stochastic Methods ◽  
Statistical Parameters ◽  
Remaining Service Life ◽  
Life Evaluation ◽  
Fatigue Damage Accumulation ◽  
Service Life Extension

When a fleet of trains is nearing the end of its service life, the city transit authorities have to decide whether to replace the aging train inventory or apply life extension remediation to the existing fleet. Replacement of the entire inventory comes at a significant cost. Therefore, evaluation of the remaining service life and possible life extension methods for the current fleet is worth investigating. The objective of this study is the evaluation of remaining service life of existing municipal trains and assessment of risk associated with life extension in order to help authorities in the decision making process of applying life extension measures or purchasing new equipment. The main factors limiting service life is exceedance of material fatigue resistance and fracture. To this end, finite element models (FEM) of the train cars in question were created in ABAQUS® modeling software to find locations of stress concentration under prescribed service loads. Locations of concern from the FEM were then used as the basis for instrumentation planning for on-site testing. A single train unit was instrumented with strain gages and accelerometers and then loaded and tested under regular operating conditions. Collected data from the on-site test was then used for calibration and validation of the FEM. Load-time history was constructed based on the calibrated FEM and the data from testing. Calculation of fatigue damage accumulation was done in accordance to the Rain-flow counting algorithm and Palmgren-Miner rule. The remaining fatigue life was evaluated based on available S-N curves from test data. Loads, as well as material resistance are random variables; therefore a reliability approach has to be applied in the calculation of risk associated with service life extension in order to make a sound recommendation as to the risk of continued service beyond the prescribed service life. Statistical parameters of load and resistance where gathered and used in calculations for this recommendation. This paper presents the approach for service life evaluation/extension, reliability and stochastic methods for risk assessment in a real world example.

A Real Time Fatigue Monitoring Platform for Flexible Risers

2021 ◽  
Author(s):  
Jiabei Yuan ◽  
Yucheng Hou ◽  
Eric Wilson ◽  
Zhimin Tan
Keyword(s):  
Service Life ◽  
Product Design ◽  
Real Time ◽  
Fatigue Damage ◽  
Input Data ◽  
Operating Conditions ◽  
Fatigue Performance ◽  
Life Extension ◽  
Service Life Extension ◽  
Flexible Risers

Abstract Fatigue life of flexible risers is a critical design factor in offshore riser system design. To estimate the fatigue damage, global and local analyses are performed inhouse with inputs from operators. Metocean data, riser properties, vessel or platform RAO data are typical inputs for the fatigue analysis. In addition to the conservatism inherited in the product design methodology and API safety factor 10 for fatigue estimation, the input data may also contain some additional conservatism compared to actual operational conditions as these were estimated/projected from limited time-span of observations or predicted purely from numerical modelling. In combination, these inheriated conservatism permits the feasibility of service life extension of the flexible riser systems. Many platforms or vessels already have real time monitoring of motions in multiple degrees of freedom and wave/current data. Furthermore, pipe internal operating conditions like pressure and temperature are usually recorded onboard. Compared to the typical input data/assumptions made in predictive analysis, these records are more precisely and directly related to the actual fatigue damage accumulation. With real time data, a more accurate estimation on fatigue performance of riser can be achieved, which could enable the service life extension without compromising the design safety factors. A special software tool has been developed to calculate the real time fatigue damage of flexible tensile wires. The software is based on product design tools which are calibrated and independently validated with over 30 years installed operational experience. Developed in Python, the software utilizes an OrcaFlex API and a local analysis algorithm in the background. The software can be customized towards different platforms and pipe systems, as well as input data types. Depending on clients’ needs, multiple fatigue hot spots like top end fitting, bend stiffener region or touch down zone can be monitored at the same time. Other parameters like riser real time extreme response or statistical results can also be checked in the software. This paper summarizes the development of the pipe monitoring system. It is believed that with real time inputs, the software can better assist clients to monitor the pipe fatigue performance and other related riser responses.

scholarly journals Structure Life Extension towards the Structural Integrity of Sukhoi Su-30MKM

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5562
Author(s):  
Arvinthan Venugopal ◽  
Roslina Mohammad ◽  
Md Fuad Shah Koslan ◽  
Ashaari Shafie ◽  
Alizarin Ali ◽  
...  
Keyword(s):  
Service Life ◽  
Structural Integrity ◽  
Simulation Analysis ◽  
Fatigue Loading ◽  
Operating Conditions ◽  
Life Assessment ◽  
Life Extension ◽  
Destructive Testing ◽  
Fighter Aircraft ◽  
Service Life Extension

The airframe structures of most fighter aircraft in the Royal Malaysian Airforce have been in service for 10 to 20 years. The effect of fatigue loading, operating conditions, and environmental degradation has led to the structural integrity of the airframe being assessed for its airworthiness. Various NDT methods were used to determine the current condition of the aircraft structure after operation of beyond 10 years, and their outcomes are summarized. In addition, although there are six critical locations, the wing root was chosen since it has the highest possibility of fatigue failure. It was further analyzed using simulation analysis for fatigue life. This contributes to the development of the maintenance task card and ultimately assists in extending the service life of the fighter aircraft. Using the concept of either safe life or damage tolerance as its fatigue design philosophy, the RMAF has adopted the Aircraft Structural Integrity Program (ASIP) to monitor the structural integrity of its fighter aircraft. With the current budget constraints and structural life extension requirements, the RMAF has embarked on the non-destructive testing method and engineering analysis. The research outcome will enhance the ASIP for other aircraft platforms in the RMAF fleet for its structure life assessment or service life extension program.

Initial Implementation of IHI Zone Logic Technology at Philadelphia Naval Shipyard

1989 ◽  
Vol 5 (02) ◽  
pp. 79-89
Author(s):  
Koichi Baba ◽  
Takao Wada ◽  
Soichi Kondo ◽  
M. S. O'Hare ◽  
James C. Schaff
Keyword(s):  
Service Life ◽  
Life Extension ◽  
Initial Application ◽  
Initial Implementation ◽  
Late Fall ◽  
The Future ◽  
Service Life Extension ◽  
Extension Program ◽  
Technical Services

Philadelphia Naval Shipyard's application of zone logic to ship overhaul is neither small nor isolated. PNSY started its implementation of zone logic in the late fall of 1986, targeting the Service Life Extension Program (SLEP) for USS Kitty Hawk (CV-63) as the initial application. The technical services of Ishikawajima-Harima Heavy Industries Co., Ltd. (IHI), Japan were contracted to assist in this transition. This implementation on the Kitty Hawk is not a trial effort but involves about one third of the production man-days and covers over one half of the compartments on the ship. The actual SLEP production work on Kitty Hawk began in January 1988. Even though it is early in the three-year SLEP, zone logic already is proving its worth. This paper explains the zone logic methods and methodology applied at PNSY on Kitty Hawk. It also discusses the future of zone logic at PNSY and its continued application.

scholarly journals Sensitivity of Service Life Extension and CO2 Emission due to Repairs by Silane Treatment Applied on Concrete Structures under Time-Dependent Chloride Attack

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Aruz Petcherdchoo
Keyword(s):  
Service Life ◽  
Concrete Structures ◽  
Treatment Strategies ◽  
Time Dependent ◽  
Life Extension ◽  
Silane Treatment ◽  
Application Time ◽  
Free Service ◽  
Chloride Attack ◽  
Service Life Extension

This paper presents sensitivity of service life extension and CO2 emission due to silane (alkyltriethoxysilane) treatment on concrete structures under time-dependent chloride attack. The service life is predicted by the Crank–Nicolson-based finite difference approach for avoiding the complexity in solving Fick’s second law. The complexity occurs due to time-dependent chloride attack and nonconstant diffusion coefficient of concrete with silane treatment. At the application time of silane treatment, the cumulative CO2 emission is assessed. The effectiveness of silane treatment is defined as the ratio of the service life extension to the cumulative CO2 emission assessed within the corrosion-free service life. The service life extension is defined as the difference between corrosion-free service life of concrete structures without and with time-based application of silane treatment. From the study, the diffusion of chlorides in concrete with silane treatment is found to be retarded. In comparison, the strategy without deterioration of silanes during effective duration is more suitable for service life extension but less effective than that with deterioration. In the sensitivity analysis, there are up to eight parameters to be determined. The service life of concrete structures without silane treatment is most sensitive to the water-to-cement ratio and the threshold depth of concrete structures. Considering only five parameters in silane treatment strategies, the service life is most sensitive to the first application time of silane treatment. The cumulative CO2 emission is most sensitive to either the first application time of silane treatment or the amount of CO2 emission per application.

Service Life Extension and CO2 Emission due to Silane Treatment on Chloride-Exposed Concrete Structures

2017 ◽  
Vol 728 ◽  
pp. 384-389
Author(s):  
Aruz Petcherdchoo ◽  
Chotima Ongsopapong
Keyword(s):  
Service Life ◽  
Concrete Structures ◽  
Treatment Strategies ◽  
Life Extension ◽  
Chloride Diffusion ◽  
Silane Treatment ◽  
Free Service ◽  
Before And After ◽  
Chloride Attack ◽  
Service Life Extension

This study presents assessment of the environmental impact in terms of the CO2 due to silane treatment for extending corrosion-free service life of concrete structures under chloride attack. To achieve this, there are two issues to be addressed; prediction of corrosion-free service life extension, and assessment of the amount of CO2 emission. In predicting the corrosion-free service life extension, the behaviors of chloride diffusion before and after time-based silane treatment are considered. Then, the cumulative CO2 due to silane treatment is accordingly calculated. The ratio of the corrosion-free service life extension to the cumulative CO2 is defined as the effectiveness of silane treatment, and used to compare different silane treatment strategies.

Structural Impact in FPSO Life Extension: A Class Perspective

2013 ◽  
Author(s):  
Christiane L. Machado ◽  
Sudheer Chand
Keyword(s):  
Service Life ◽  
Oil And Gas ◽  
Structural Response ◽  
Oil And Gas Industry ◽  
Environmental Data ◽  
Life Extension ◽  
Element Analysis ◽  
Actual Performance ◽  
Remaining Service Life ◽  
The Impact

The Offshore Oil and Gas Industry has converted a large number of units from trading tankers and carriers into Floating Production, Storage and Offloading units (FPSOs). Several of these have been moored offshore Brazil during the last 15 years. Following the discovery of offshore pre-salt fields some years ago, demand for FPSOs has increased, and the forecasts for productive field lives have grown. The result of these developments is the need to extend the service lives of existing FPSOs. The main aim of this study is to investigate FPSO structural response to environmental conditions and functional loads, considering the actual available tools for numerical simulations and Rule requirements, which currently are basic requirements for design review for Classification. The procedure was developed from one selected FPSO converted from a trading Very Large Crude Carrier (VLCC) tanker approximately 15 years ago and includes investigation of the impact on hull behavior comparing the motion analyses of the production unit under environmental data and software capabilities available at the period of conversion and actual performance: variances in the environmental (sea scatter diagrams) datasets; updates to Classification requirements for defining offloading conditions, environmental loads, acceptance criteria and remaining fatigue life (RFL); and incorporating the most recent gauged thickness for primary structure. The selected FPSO was evaluated according to prescriptive Rule requirements and also using finite element analysis, taking into account the previous conditions of Classification approval as well as the actual requirements and available data. Structural analysis included one global model and some local refined models to address strength, buckling and fatigue capacity of the typical portions/connections of the hull. The comparisons performed from the results of these analyses are a crucial step toward understanding the structural capacity of the FPSO at the conversion stage, its performance during the last 15 years, and its remaining service life. Differences were tabulated and evaluated so that a more precise level of uncertainty could be achieved for predicting the estimated remaining service life, and consequently, a new and dedicated approach to investigate the existing FPSO fleet is being generated.

Service life extension for rock cutters by increasing wear resistance of holders by thermomechanical treatment

2019 ◽  
pp. 67-71 ◽  
Author(s):  
V. I. Bolobov ◽  
◽  
S. A. Chupin ◽  
V. S. Bochkov ◽  
I. I. Mishin ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Service Life ◽  
Thermomechanical Treatment ◽  
Life Extension ◽  
Service Life Extension
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