Identification Of Failure Modes Research Articles

Failure Mode Identification and End of Life Scenarios of Offshore Wind Turbines: A Review

In 2007, the EU established challenging goals for all Member States with the aim of obtaining 20% of their energy consumption from renewables, and offshore wind is expected to be among the renewable energy sources contributing highly towards achieving this target. Currently wind turbines are designed for a 25-year service life with the possibility of operational extension. Extending their efficient operation and increasing the overall electricity production will significantly increase the return on investment (ROI) and decrease the levelized cost of electricity (LCOE), considering that Capital Expenditure (CAPEX) will be distributed over a larger production output. The aim of this paper is to perform a detailed failure mode identification throughout the service life of offshore wind turbines and review the three most relevant end of life (EOL) scenarios: life extension, repowering and decommissioning. Life extension is considered the most desirable EOL scenario due to its profitability. It is believed that combining good inspection, operations and maintenance (O&M) strategies with the most up to date structural health monitoring and condition monitoring systems for detecting previously identified failure modes, will make life extension feasible. Nevertheless, for the cases where it is not feasible, other options such as repowering or decommissioning must be explored.

Design validation of the ITER EC upper launcher according to codes and standards

The ITER electron cyclotron (EC) upper launcher has passed the CDR (conceptual design review) in 2005 and the PDR (preliminary design review) in 2009 and is in its final design phase now. The final design will be elaborated by the European consortium ECHUL-CA with contributions from several research institutes in Germany, Italy, the Netherlands and Switzerland. Within this consortium KIT is responsible for the design of the structural components (the upper port plug, UPP) and also the design integration of the launcher.As the selection of applicable codes and standards was under discussion for the past decade, the conceptual and the preliminary design of the launcher structure were not elaborated in straight accordance with a particular code but with a variety of well-acknowledged engineering practices. For the final design it is compulsory to validate the design with respect to a typical engineering code in order to be compliant with the ITER quality and nuclear requirements and to get acceptance from the French regulator.This paper presents typical design validation of the closure plate, which is the vacuum and Tritium barrier and thus a safety relevant component of the upper port plug (UPP), performed with the ASME boiler and pressure vessel code. Rationales for choosing this code are given as well as a comparison between different design methods, like the “design by rule” and the “design by analysis” approach. Also the selections of proper load specifications and the identification of potential failure modes are covered. In addition to that stress categorizations, analyses results, and prove of the soundness of the design are presented.

Improved Failure Mode Identification and Reliability Estimates for Electricity Transmission Towers

Studies on the theory of structural system reliability includes identifi- cation of main the failure modes and calculation of inclusive failure probabilities for the structural system. The efficient and accurate identification of failure modes in structural systems is difficult and represents a key focus for research in sys- tem reliability. The fundamental theory of the branch and bound algorithm for stage critical strength is reviewed in this paper. Some deficiencies in this method are highlighted. Corresponding approaches to overcome these deficiencies are pro- posed. Calculated system reliability solutions to the classical model, a truss with 10 elements, indicate that the improvement measures proposed in this paper increase the efficiency of recognising the main failure modes of the structural system, and are readily validated. The outcomes of this type of benchmark analysis suggest that the proposed methodology may be capable of representing a suitable basis for the structural system reliability analysis of complex truss-like structures, includ- ing transmission towers. Using the proposed approach, the principal failure modes and system reliability of a transmission tower are calculated. Based on practical engineering considerations, effective methods to improve this structural system re- liability are proposed.

DESIGN FAILURE MODES AND EFFECTS ANALYSIS (DFMEA) OF AN ALL-TERRAIN VEHICLE

Society of Automotive Engineers (SAE) organizes a student engineering design competition named Baja in which an All-terrain vehicle (ATV) is designed and fabricated by undergraduate engineering students. ATV is a vehicle that can run on a wide variety of terrains and travels on low-pressure tires with a seat straddled by the operator. SAE BAJA involves designing and fabrication of a modified and scaled down smaller version of ATV. Starting from initial design and analysis to actual fabrication of ATV, everything is done by the students. As in any engineering design, there is a constant need to design a safe and sustainable vehicle. This involves predicting and defining all failure modes in the initial design step itself. An effective method of doing this failure analysis is DFMEA (Design Failure Modes and Effects Analysis), which is an extension of popular Failure Modes and Effects Analysis (FMEA) technique and is done in the design stage. In this paper DFMEA technique is used to list out all modes of failure for various components of the ATV, its causes, effects and ways of preventing it. Risk Priority Number methodology of FMEA is used to find out the components which are more susceptible to failure and needs more attention than others.

Multi-institutional application of Failure Mode and Effects Analysis (FMEA) to CyberKnife Stereotactic Body Radiation Therapy (SBRT).

BackgroundA multidisciplinary and multi-institutional working group applied the Failure Mode and Effects Analysis (FMEA) approach to assess the risks for patients undergoing Stereotactic Body Radiation Therapy (SBRT) treatments for lesions located in spine and liver in two CyberKnife® Centres.MethodsThe various sub-processes characterizing the SBRT treatment were identified to generate the process trees of both the treatment planning and delivery phases. This analysis drove to the identification and subsequent scoring of the potential failure modes, together with their causes and effects, using the risk probability number (RPN) scoring system. Novel solutions aimed to increase patient safety were accordingly considered.ResultsThe process-tree characterising the SBRT treatment planning stage was composed with a total of 48 sub-processes. Similarly, 42 sub-processes were identified in the stage of delivery to liver tumours and 30 in the stage of delivery to spine lesions. All the sub-processes were judged to be potentially prone to one or more failure modes. Nineteen failures (i.e. 5 in treatment planning stage, 5 in the delivery to liver lesions and 9 in the delivery to spine lesions) were considered of high concern in view of the high RPN and/or severity index value.ConclusionsThe analysis of the potential failures, their causes and effects allowed to improve the safety strategies already adopted in the clinical practice with additional measures for optimizing quality management workflow and increasing patient safety.

A Literature Survey and Future Directions for Product Development: A Focus on Conceptual Design Stage

Product development process follows a sequence of activities, methods, and tools to design and develop a high quality product. An optimized strategy for a single generation product development may not be the best choice when multi-generation scenarios are considered. In this article an attempt has been made to study the nature of multi-generational product development and compare it with that of single generation product development to drive validating arguments. Further, a qualitative analysis framework for multi-generational product development is developed to identify correct user requirements and to propose a reusability concept during the concept design stage. In order to capture the right customer requirements clearly in the product definition phase, axiomatic design with design failure mode and effects analysis approach is reviewed. For architecture development, the design for modularity and design for reusability have been discussed. This qualitative analysis framework is based on the related case...

A performance evaluation of three inference engines as expert systems for failure mode identification in shafts

This paper aims to present performance evaluation of three different inference engines (rule based reasoning, fuzzy based reasoning and Bayesian based reasoning) for failure mode identification in shafts. This research was done with a focus on the validation cases and results after their use in failure cases from several industries where the three systems were tested under the same conditions.Each system was implemented using the same user interface and knowledge base, with different frameworks and techniques as follows: rule based inference reasoning (prolog, C#), Mamdani-fuzzy based reasoning (C, MATLAB®) and Bayesian based reasoning with a variable elimination algorithm (C, MATLAB®).The best performance was obtained using the Bayesian inference engine. The conditional probabilities give flexibility when evidence is not listed, while the fuzzy and classical IF-THEN systems depend on the rules in the inference engine.The process presented in this paper could be used for validation of any expert system or for comparison with other expert systems (inference engines) when the knowledge base is the same.

Masonry infill walls under blast loading using confined underwater blast wave generators (WBWG)

The vulnerability of the masonry envelop under blast loading is considered critical due to the risk of loss of lives. The behaviour of masonry infill walls subjected to dynamic out-of-plane loading was experimentally investigated in this work. Using confined underwater blast wave generators (WBWG), applying the extremely high rate conversion of the explosive detonation energy into the kinetic energy of a thick water confinement, allowed a surface area distribution avoiding also the generation of high velocity fragments and reducing atmospheric sound wave. In the present study, water plastic containers, having in its centre a detonator inside a cylindrical explosive charge, were used in unreinforced masonry infills panels with 1.7m by 3.5m. Besides the usage of pressure and displacement transducers, pictures with high-speed video cameras were recorded to enable processing of the deflections and identification of failure modes. Additional numerical studies were performed in both unreinforced and reinforced walls. Bed joint reinforcement and grid reinforcement were used to strengthen the infill walls, and the results are presented and compared, allowing to obtain pressure–impulse diagrams for design of masonry infill walls.

Cure cycle effect on impact resistance under elevated temperatures in carbon prepreg laminates investigated using acoustic emission

Voids in composites have been a perennial problem, since the amount of porosities is deemed to bear a strong relation with the degradation of service performance of laminates. On the other side, the effect of porosity on impact resistance of laminates is often dependant on their distribution in the material, especially with respect to the location and severity of impact damage in it. In this study, the influence of void content percentage on the residual flexural strength of CFRP laminates impacted at very low energy, in the region of 1 J, at different temperatures was investigated. Laminates were fabricated using 16 layers of Cycom 977-2 prepreg material in a [0/90/90/0]2S layup with different void contents in the range from 1 to 7% by varying cure conditions. Low velocity impact tests were conducted on three categories of laminates, defined as high pressure cured, low pressure debulked and low pressure non debulked respectively, each of these at ambient temperature (30 °C) and elevated temperatures of 50, 70 and 90 °C. Post-impact residual flexural strength of the laminates was measured by three-point bending tests followed in real time by acoustic emission (AE) monitoring. From the separation of frequency bands and of their amplitude levels, identification of the different failure modes, such as matrix cracking, delamination and fibre failure, was performed. The results indicated that in the case of very low impact energy high porosity laminates, such as non debulked ones, may possess slightly higher residual flexural strength and an enhanced delamination resistance with respect to debulked ones.

Practical Implementation of Failure Mode and Effects Analysis for Safety and Efficiency in Stereotactic Radiosurgery

To improve the safety and efficiency of a new stereotactic radiosurgery program with the application of failure mode and effects analysis (FMEA) performed by a multidisciplinary team of health care professionals. Representatives included physicists, therapists, dosimetrists, oncologists, and administrators. A detailed process tree was created from an initial high-level process tree to facilitate the identification of possible failure modes. Group members were asked to determine failure modes that they considered to be the highest risk before scoring failure modes. Risk priority numbers (RPNs) were determined by each group member individually and then averaged. A total of 99 failure modes were identified. The 5 failure modes with an RPN above 150 were further analyzed to attempt to reduce these RPNs. Only 1 of the initial items that the group presumed to be high-risk (magnetic resonance imaging laterality reversed) was ranked in these top 5 items. New process controls were put in place to reduce the severity, occurrence, and detectability scores for all of the top 5 failure modes. FMEA is a valuable team activity that can assist in the creation or restructuring of a quality assurance program with the aim of improved safety, quality, and efficiency. Performing the FMEA helped group members to see how they fit into the bigger picture of the program, and it served to reduce biases and preconceived notions about which elements of the program were the riskiest.

A case study on FMEA-based quality improvement of packaging designs in the TFT-LCD industry

Nowadays enterprises are encountering diversified customer requirements, and using market information well is critical to product development. It is extremely important to conduct risk planning, prevent potential failures, and reduce uncertain factors by transforming customer requirements into exact development targets. This study is based on the method of quality function deployment (QFD) and failure modes and effects analysis (FMEA). The package design for semi-finished products of thin film transistor-liquid crystal display (TFT-LCD) modules in the photoelectricity industry was selected as a case study. First, customers conducted a questionnaire survey which helped determine the items they demanded. Second, QFD has been combined with FMEA to serve as the standard of evaluating the importance of customer requirements. Through mutual assessments and investigations by QFD and design failure mode and effects analysis (DFMEA), the key factors of a product design can be determined. The results of design of experiments verified that this method indeed effectively reduced defective products and customer complaints. The average number of customer complaints per year has been reduced from 9.5 to just only one after the introduction of the proposed method, which has been verified to assist in rapidly developing new products during the early design stage. This approach also reduces possible losses and enhances competitiveness.

Failure Modes and Effects Analysis (FMEA) Technique:A Literature Review

Risk management and improve the reliability of the process, are the issues which have become more important in production and operations management literature. Risk assessment is an important tool in risk management to reduce project risks and achieve sustainable development. At present the risk assessment is concerned in planning and policy-making in most of the world countries. There are several techniques for identifying hazards and assessing risks. One of the most important of these techniques is Failure Modes and Effects Analysis (FMEA). FMEA is an efficient tool for the identification of potential failure modes and their effects in order to increase the reliability and safety of complex systems. Also this technique is useful to gather data needed for decision making and risk control. In fact, the purpose of this technique is: a. to identify failure modes and their effects; b. to specify the corrective actions to eliminate or reduce the probability of failure and ultimately c. development of efficient maintenance system to reduce the occurrence of potential scenarios. In this study, several other studies have investigated and tried to explore a range of its benefits and uses and also the method of risks computation using this technique is presented.

Conceptual Design of Shock Absorbing Bicycle Wheel

Bicycle suspension helps to cushion and insulate rider from the roughness of terrain. Till now fork suspension attached to the steering column is used to save the rider from impact. In this paper, a research involving the design of bicycle wheel that has a spring system between the hub and rim of wheel which provide tangential suspension to the rider from bumps and potholes on the road is reported. During this research, concept sketches for the proposed design were arrived from morphological chart and then Pugh chart was used for concept selection. Material indices were arrived for bow spoke that act as spring system and suitable material was suggested. Design Failure Mode and Effects Analysis was done for the proposed design concept and recommendations to reduce the risk priority number were discussed. Detailed design was carried out by considering factors that affect the stability of the bicycle.

The Pennsylvania State University's Advanced Vehicle Team: EcoCAR3 Year One Final Technical Report

This paper details the powertrain modeling and control strategies the Penn State Advanced Vehicle Team (PSUAVT) developed for submission to the EcoCAR 3 competition, an advanced vehicle design competition in which university teams compete to hybridize a stock 2016 Chevrolet Camaro. The team utilized model-in-the-loop studies using both public-domain and custom-built vehicle simulation packages to undergo an iterative powertrain model development process. This analysis lead to the development of a pre-transmission plug-in parallel hybrid electric vehicle that uniquely meets PSUAVT's goals. The design process was guided by vehicle technical specifications (VTS) based on consumer market research as well as the team's emphasis on producing a technically-feasible but performance-weighted hybrid architecture.Component models are presented that blend physics-based and map-based methods. A heuristic master vehicle controller (MVC) is described that splits the required driving torque between the motor and engine so engine brake-specific fuel consumption (BSFC) is minimized. Fault analysis of this controller is also presented based on design failure mode and effects analysis (DFMEA) performed in previous studies.

SRB Field Joints Failure Analysis Using Fuzzy FMEA

SRB Field Joints Failure Analysis Using Fuzzy FMEA Kouroush Jenab, Raymond M. Blecher, Saeid Moslehpour Abstract The Challenger space shuttle disaster was due to failure of a solid rocket booster field joint. The NASA management and engineering team’s failed in utilizing Failure Mode & Effect Analysis (FMEA) in proper identification and communication of critical system failure modes and their effects. The benefits of fuzzy logic and its application to FMEA methodology could have made a major difference in the outcome as it would have provided more granularities to the risk priority rating. This study reports a platform for performing FMEA that utilizes a conflict resolution module in order to dilute the conflict in risk priority ratings. The platform has been applied to a real case to demonstrated the its application. Full Text: PDF DOI: 10.15640/ijpa.v3n1a1

DesktopLabs] Desktop Laboratories: Web Share and Additive Manufacture of Engineering Educational Models

Physical models are desirable in engineering education as they enhance visual literacy, provide insight into critical design failure modes and design attributes, and can be implemented in a classroom scenario in concert with multimedia displays and lecture slides. Despite the advantage, such physical models are often: not commercially available; are excessively costly; are not tailored to the intended learning outcomes; or are difficult to share across multiple geographic locations. In this work, the authors have developed an approach to address these shortcomings by exploiting the emerging capabilities of additive manufacturing equipment, increasingly present within educational institutions. The [DesktopLabs] project engages students to develop and additively manufacture physical models, to allow in-class demonstration of complex systems that would not be otherwise possible. By engaging with physical models of technical systems, students enhance their capacity to engage with emerging engineering technologies, and to solve new and complex problems. Combined with access to online sharing facilities, [DesktopLabs] allow web share of the developed model files, thereby allowing ready dissemination amongst other educators for additive manufacture in other geographic locations. Although applied in an engineering context, the benefit of [DesktopLabs] are directly transferrable to teaching areas to aid in the education of successive generations of undergraduate and postgraduate students.

A failure-path independent method for analysis of structural system reliability

In order to overcome the disadvantages of traditional system reliability methods in the identification of significant failure modes and calculation of joint failure probability, a failure-path independent method is presented for structural system reliability analysis by combining the elastic modulus reduction method and the stochastic finite element method (SFEM). The stochastic responses by the SFEM were employed to define the element bearing ratio and the reference EBR, based on which an efficient dynamic criterion was developed for identification of highly stressed elements. The stochastic elastic modulus reduction method was proposed for simulation of internal force redistribution and damage evolution based on the principle of deformation energy conservation. The significant failure modes of structural system were identified according to the elastic modulus of the highly stressed elements in the limit state, while structural system reliability was calculated based on the joint failure probability of multi-failure modes. Investigation demonstrated the advantages of the proposed method over the traditional system reliability methods and its high accuracy and efficiency.

The Improvement of a Novel Radiation Therapy Workflow by Failure Mode and Effects Analysis

The Improvement of a Novel Radiation Therapy Workflow by Failure Mode and Effects Analysis

Safety and feasibility of STAT RAD: Improvement of a novel rapid tomotherapy-based radiation therapy workflow by failure mode and effects analysis

PurposeThe clinical challenge of radiation therapy (RT) for painful bone metastases requires clinicians to consider both treatment efficacy and patient prognosis when selecting a radiation therapy regimen. The traditional RT workflow requires several weeks for common palliative RT schedules of 30 Gy in 10 fractions or 20 Gy in 5 fractions. At our institution, we have created a new RT workflow termed “STAT RAD” that allows clinicians to perform computed tomographic (CT) simulation, planning, and highly conformal single fraction treatment delivery within 2 hours. In this study, we evaluate the safety and feasibility of the STAT RAD workflow. Methods and materialsA failure mode and effects analysis (FMEA) was performed on the STAT RAD workflow, including development of a process map, identification of potential failure modes, description of the cause and effect, temporal occurrence, and team member involvement in each failure mode, and examination of existing safety controls. A risk probability number (RPN) was calculated for each failure mode. As necessary, workflow adjustments were then made to safeguard failure modes of significant RPN values. After workflow alterations, RPN numbers were again recomputed. ResultsA total of 72 potential failure modes were identified in the pre-FMEA STAT RAD workflow, of which 22 met the RPN threshold for clinical significance. Workflow adjustments included the addition of a team member checklist, changing simulation from megavoltage CT to kilovoltage CT, alteration of patient-specific quality assurance testing, and allocating increased time for critical workflow steps. After these modifications, only 1 failure mode maintained RPN significance; patient motion after alignment or during treatment. ConclusionsPerforming the FMEA for the STAT RAD workflow before clinical implementation has significantly strengthened the safety and feasibility of STAT RAD. The FMEA proved a valuable evaluation tool, identifying potential problem areas so that we could create a safer workflow.

A systematic approach to improving intrauterine device services in family planning clinics

ObjectivesTo improve the quality of intrauterine device (IUD) services at Title X clinics. Study DesignFailure Modes Effects and Criticality Analysis (FMECA) is a step-by-step approach, adopted for healthcare, in which team members evaluate the systems and processes of a specific type of clinical care (e.g., IUD care) in order to identify practices that contribute to poor quality, unsafe, unreliable, or inefficient care. These weaknesses are termed “failures.” The FMECA uses qualitative (e.g., meetings) and quantitative (e.g., clinical operations) data to determine failure frequency and impact in order to prioritize the parts of a clinical care system or process to be redesigned and improved.An FMECA was conducted in three community-based Title X family planning clinics on the South and West Sides of Chicago, IL with all care team members; IUD clients were also interviewed regarding their visit. Clinic administrative data was also assessed to determine the frequency and impact of the identified failures. ResultsAfter combining the FMECA and clinical operations data, “critical” areas across all three clinics were: (1) client does not show up for or cancels appointment; (2) client is ineligible for an IUD insertion due to unprotected intercourse; and (3) limited time for counseling, informing, and placing IUDs. As most insertions were successful, failed IUD insertion was not considered a high-risk failure. ConclusionsThis process revealed that the failures most in need of improvement and redesign were the scheduling and intake processes and the lack of time for counseling during certain types of visits. ImplicationsA systematic assessment of the underlying problems in IUD-care revealed three important issues across three clinics: (1) client does not show up for appointment or cancels appointment; (2) client recently had unprotected intercourse; and (3) limited time for counseling, informing, and placing IUDs.