Case Study: Failure Analysis of a BFJ in Cyclic Service

2014 ◽  
Author(s):  
Trevor G. Seipp
Keyword(s):  
Temperature Cycle ◽  
Flange Joint ◽  
Element Analysis ◽  
Mean Time Between Failures ◽  
Time Between Failures ◽  
Cause Of Failure ◽  
Cyclic Service ◽  
Bolted Flange ◽  
Mean Time

A bolted flange joint was in cyclic temperature and pressure service in a natural gas dehydrator (mole sieve) vessel. The flange joint suffered from multiple failures on a frequent (9 month) basis. This paper details the investigation into the failure and highlights the most probable cause of failure. A finite element analysis of the pressure and temperature transients in the bolted flange joint pointed to the temperature cycle as tending to unload the joint. Then, a parametric study was undertaken to evaluate the effectiveness of potential solutions. The bolted flange joint was placed back into service and has been operating for more than three times the prior mean time between failures.

Reliability of on-site greywater treatment systems in Mediterranean and arid environments – a case study

2013 ◽  
Vol 67 (6) ◽  
pp. 1389-1395 ◽  
Author(s):  
Y. Alfiya ◽  
A. Gross ◽  
M. Sklarz ◽  
E. Friedler
Keyword(s):  
Arid Environments ◽  
Single Family ◽  
Mean Time Between Failures ◽  
Time Between Failures ◽  
Maintenance Work ◽  
Failure Tree ◽  
The Right ◽  
Mean Time ◽  
Impaired Quality

On-site greywater (GW) treatment and reuse is gaining popularity. However, a main point of concern is that inadequate treatment of such water may lead to negative environmental and health effects. Maintenance of single-family home GW systems is usually performed by home owners with limited professional support. Therefore, unless GW systems are reliable, environmental and public health might be compromised. This study is aimed at investigating the reliability of on-site recirculated vertical flow constructed wetlands (RVFCW) in 20 single-family homes. In order to ensure reliability, the failure-tree approach was adopted during the design and construction of the systems. The performance of the systems was monitored for 1.5 years, by evaluating treated GW flow and quality, and by recording all malfunctions and maintenance work. Only 39 failures occurred during this period, of which four caused irrigation with impaired quality GW, while the rest led to no irrigation. The mean time between failures (MTBF) was 305 days; two out of the 20 systems suffered from seven malfunctions (each), while nine systems did not fail at all. Thus, it can be postulated that if on-site GW treatment systems are designed with the right controls, and if scheduled (basic and relatively infrequent) maintenance is performed, GW reuse can be safe to the environment and human health.

Case Study on Reliability of Automotive Painting Shop Robots

2015 ◽  
Vol 1125 ◽  
pp. 516-520
Author(s):  
Mohd Amin Abd Majid ◽  
Ahmad Fauzi Fudzin
Keyword(s):  
Reliability Analysis ◽  
High Reliability ◽  
Mean Time Between Failures ◽  
Assembly Plant ◽  
Failure Data ◽  
Time Between Failures ◽  
Plant Maintenance ◽  
Automotive Assembly ◽  
Mean Time

Robots in automotive assembly plant are crucial for automation of the plant. As the robots are expensive, they are the main contributor to plant investment. Thus, it is important for the robots to have high reliability. This paper presents the reliability analysis of robots at an automotive assembly plant. The analysis was based on operating hours and frequency of the failures of the robots. The data were acquired from plant maintenance data. Using seven years of failure data, the robots’ mean time between failures (MTBF) and reliability were evaluated. Constant failure rate was assumed in the analysis. From the analysis it is noted that the reliability of the robots at the plant varies from 15% to 62% and 2% to 39% for 10,000 hours and 20,000 hours respectively. These findings could assist the maintenance manager to schedule the maintenance and replacement of the robot at the plant.

Review of Technological Advancements and HSE-Based Safety Model for Deep-Water Human Occupied Vehicles

2014 ◽  
Vol 48 (3) ◽  
pp. 25-42 ◽  
Author(s):  
Narayanaswamy Vedachalam ◽  
Gidugu Ananada Ramadass ◽  
Malayath Aravindakshan Atmanand
Keyword(s):  
Deep Water ◽  
Capital Expenditure ◽  
Mean Time Between Failures ◽  
Safety Integrity Level ◽  
Geological Surveys ◽  
Time Between Failures ◽  
High Resolution Bathymetry ◽  
Safety Systems ◽  
Mean Time ◽  
Safety And Environment

AbstractThis paper reviews the latest advancements in subsea technologies associated with the safety of deep-water human occupied vehicles. Human occupied submersible operations are required for deep-water activities, such as high-resolution bathymetry, biological and geological surveys, search activities, salvage operations, and engineering support for underwater operations. As this involves direct human presence, the system has to be extremely safe and reliable. Based on applicable IEC 61508 Standards for health, safety, and environment (HSE), the safety integrity level requirements for the submersible safety systems are estimated. Safety analyses are done on 10 critical submersible safety systems with the assumption that the submersible is utilized for 10 deep-water missions per year. The results of the analyses are compared with the estimated target HSE requirements, and it is found that, with the present technological maturity and safety-centered design, it is possible to meet the required safety integrity levels. By proper maintenance, it is possible to keep the mean time between failures to more than 9 years. The results presented shall serve as a model for designers to arrive at the required trade-off between the capital expenditure, operating expenditure, and required safety levels.

Finite Element Analysis of a Gasketed Flange Joint Under Combined Internal Pressure and Thermal Transient Loading

2007 ◽  
Author(s):  
Muhammad Abid ◽  
Javed A. Chattha ◽  
Kamran A. Khan
Keyword(s):  
Finite Element Analysis ◽  
Steady State ◽  
Internal Pressure ◽  
Thermal Loading ◽  
Flange Joint ◽  
Element Analysis ◽  
Transient Loading ◽  
Thermal Transient ◽  
Transient Thermal ◽  
Bolted Flange

Performance of a bolted flange joint is characterized mainly by its ‘strength’ and ‘sealing capability’. A number of analytical and experimental studies have been conducted to study these characteristics only under internal pressure loading. In the available published work, thermal behavior of the pipe flange joints is discussed under steady state loading with and without internal pressure and under transient loading condition without internal pressure. The present design codes also do not address the effects of steady state and thermal transient loading on the structural integrity and sealing ability. It is realized that due to the ignorance of any applied transient thermal loading, the optimized performance of the bolted flange joint can not be achieved. In this paper, in order to investigate gasketed joint’s performance i.e. joint strength and sealing capability under combined internal pressure and transient thermal loading, an extensive nonlinear finite element analysis is carried out and its behavior is discussed.

Bolted Flange Joint Made of Glass Fibre Reinforced Polymer (GFRP) for Oil and Gas Pipelines

2018 ◽  
Author(s):  
Muhsin Aljuboury ◽  
Md Jahir Rizvi ◽  
Stephen Grove ◽  
Richard Cullen
Keyword(s):  
Glass Fibre ◽  
Oil And Gas ◽  
High Strength ◽  
Flange Joint ◽  
Element Analysis ◽  
Glass Fibre Reinforced Polymer ◽  
Linear Behaviour ◽  
Glass Fibre Reinforced ◽  
Gasket Material ◽  
Bolted Flange

The objective of this work is an experimental and numerical investigation for a bol Richard Cullen ted composite flange connection for composite pipes, which are used in the oil and gas applications, and obtain a joint with high strength and high corrosion resistance. For the experimental part, we have designed and manufactured the required mould, which ensures the quality of the composite materials and controls its surface grade. Based on the ASME Boiler and Pressure Vessel Code, Section X, this GFRP flange has been fabricated using biaxial glass fibre braid and polyester resin in a vacuum infusion process. Numerically, an investigation is carried out using 3D finite element analysis (FEA) of a bolted GFRP flange joint including flange, pipe, gasket and bolts. This model has taken into account the orthotropy of the GFRP material and the non-linear behaviour of the rubber gasket material for both the loading and non-loading conditions. Furthermore, the leakage propagation between the flange and the gasket has also been simulated in this investigation by using the pressure-penetration criteria PPNC in ANSYS. Finally, the flange has been tested under the internal pressure and the agreement between the experimental and numerical results is excellent.

scholarly journals A Statistical State Analysis of a Marine Gas Turbine

Actuators ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 54 ◽  
Author(s):  
Suzana Lampreia ◽  
Valter Vairinhos ◽  
Victor Lobo ◽  
José Requeijo
Keyword(s):  
Gas Turbine ◽  
Point Of View ◽  
Operating Conditions ◽  
Environmental Data ◽  
Statistical Point ◽  
Mean Time Between Failures ◽  
Time Between Failures ◽  
Intervention Plan ◽  
Mean Time

This paper describes the analysis, from a statistical point of view, of a maritime gas turbine, under various operating conditions, so as to determine its state. The data used concerns several functioning parameters of the turbines, such as temperatures and vibrations, environmental data, such as surrounding temperature, and past failures or quasi-failures of the equipment. The determination of the Mean Time Between Failures (MTBF) gives a rough estimate of the state of the turbine, but in this paper we show that it can be greatly improved with graphical and statistical analysis of data measured during operation. We apply the Laplace Test and calculate the gas turbine reliability using that data, to define the gas turbine failure tendency. Using these techniques, we can have a better estimate of the turbine’s state, and design a preventive observation, inspection and intervention plan.

Comparison of the Mean Time Between Failures for Two Systems Under Short Tests

2009 ◽  
Vol 58 (4) ◽  
pp. 589-596 ◽  
Author(s):  
Y.H. Michlin ◽  
G.Y. Grabarnik ◽  
E. Leshchenko
Keyword(s):  
Mean Time Between Failures ◽  
Time Between Failures ◽  
Two Systems ◽  
The Mean ◽  
Mean Time
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