Search results for "reliability"
showing 10 items of 1563 documents
A force measuring based strategy for failure prevention in incremental forming
2006
Abstract Incremental forming processes show a number of advantages compared to the traditional processes but, at the same time, some drawbacks are clearly known. Current problems, include the slowness of the process, low accuracy and a lack of knowledge in the field of material formability. This paper is focused on the latter issue: an industrially oriented methodology for detecting the approach of failure in incremental forming is proposed. The approach is based on the analysis of the trend of the forming force in order to assess whether the process can be run safely. If not, a proper strategy, to avoid material failure, is proposed and experimentally validated.
Product lifecycle management support: a challenge in supporting product design and manufacturing in a networked economy
2005
In this paper, we provide an overview of the changing design and manufacturing landscape in the 21st century that has come about because of IT and the changing global conditions. Based on this overview and a review of the current state of IT for PLM support in the design and manufacturing sector, we identify the areas of need for standards. A review of areas covered by standards leads us to the development of an initial typology of standards and a potential path for bringing convergence of these standards in support of PLM. We make a case throughout the paper that given the nature of the task we need to aspire to create open standards with wide participation. We conclude by arguing that the…
Fault diagnosis and modeling of the liquids packaging process. A research based on Petri Nets
2008
Searching for solutions to manufacture industries, which every day deal with problems of faults in their process, that generate economics and humans main losses, an algorithm to construct a Petri Nets based model and diagnoser to isolate and fault detection of discrete events systems is presented. This algorithm is developed in a real process of liquids packaging, where we can see that its implementation allows detecting individuals, simultaneous and dependents faults. The process to construct the model and diagnoser is systematic and useful, and it reduces the problems of combinational explosion, which is the main problem present in other investigations. This research has an excellent proj…
Variation Mode and Effect Analysis: a Practical Tool for Quality Improvement
2006
This paper describes a statistically based engineering method, variation mode and effect analysis (VMEA), that facilitates an understanding of variation and highlights the product/process areas in which improvement efforts should be targeted. An industrial application is also described to illustrate how the VMEA can be used for quality improvement purposes. Copyright © 2006 John Wiley & Sons, Ltd.
Automated Calculation Method to Determine the Output Power Based on the Frequency for Induction Heating IGBT Parallel Inverter
2007
The fact that some inverter topologies used in induction heating applications allow the soft switching working operation lets the progressive replacement of the MOSFET with the IGBT in high power inverters. This is due to two main reasons, the former is the IGBT reliability and the latter is the ratio defined as the price of the component per output power. In this article an automated method to determine the output power based on the frequency of an inverter build with different IGBT is described. To carry out this method is necessary to define the power cycle and to develop the calculation process which determines the energy losses in the working conditions of the resonant parallel inverte…
Semiactive control for floating offshore wind turbines subject to aero-hydro dynamic loads
2011
Wind and wave dynamic loads might cause undesirable vibrations that affect the structure integrity and system performance of floating offshore wind turbines. This paper addresses the problem of dynamic load mitigation by using semiactive control techniques with the tuned liquid column dampers placed on the turbine’s tower. The control law is formulated based on the mixed H2/H∞ methods for ensuring the system stability and reliability. Furthermore, the proposed controller only uses output feedback so as to avoid the dependence on the knowledge of the states of the system. Peer Reviewed
Requirements Engineering and Process Modelling in Software Quality Management— Towards a Generic Process Metamodel
2004
This paper examines the concept of Quality in Software Engineering, its different contexts and its different meanings to various people. It begins with a commentary on quality issues for systems development and various stakeholders' involvement. It revisits aspects and concepts of systems development methods and highlights the relevance of quality issues to the choice of a process model. A summarised review of some families of methods is presented, where their application domain, lifecycle coverage, strengths and weaknesses are considered. Under the new development era the requirements of software development change; the role of methods and stakeholders change, too. The paper refers to the …
Validation of the group nuclear safety climate questionnaire.
2013
Abstract Introduction Group safety climate is a leading indicator of safety performance in high reliability organizations. Zohar and Luria (2005) developed a Group Safety Climate scale (ZGSC) and found it to have a single factor. Method The ZGSC scale was used as a basis in this study with the researchers rewording almost half of the items on this scale, changing the referents from the leader to the group, and trying to validate a two-factor scale. The sample was composed of 566 employees in 50 groups from a Spanish nuclear power plant. Item analysis, reliability, correlations, aggregation indexes and CFA were performed. Results Results revealed that the construct was shared by each unit, a…
A combined multi-criteria approach to support FMECA analyses: A real-world case
2018
[EN] The paper proposes an approach that combines reliability analyses and multi-criteria decision methods to optimize maintenance activities of complex systems. A failure mode, effects, and criticality analysts (FMECA) is initially performed and the fuzzy TOPSIS (FTOPSIS) method is then applied to rank previously identified failure modes. For prioritization, failure modes are assessed against three evaluation criteria that differ from those traditionally involved in risk priority number (RPN) computation (i.e. severity, occurrence and detection). Two criteria refer to the maintenance management reflecting the operational time taken by the maintenance activity performed after the occurrence…
An optimized diagnostic architecture for real-time monitoring of MV networks
2006
Due to the electrical energy market liberalization, the Authority for electrical energy and gas (AEEG) in Italy and the other regulatory organizations in other European countries have concentrated their attention on the quality of the electrical service. One of the aspect of major importance in the definition of the quality of a public service is its continuity. In the aim of regulating this field the Authority has defined some continuity indicators, for example the number of interruptions per year and the cumulate duration of the interruptions per year. Recent statistics on these indicator show that the 80% of the number of interruptions in one year is caused by MV network. For this reason…