102,107 research outputs found
Stress concentration analysis of plate with circular hole : elasticity theory and finite element comparison
Stress concentration factor for a plate with circular free stress hole subjected to a uniform far field tension in single was investigated in this study. The stress concentration level along X and Y axis was determined by the elasticity theoritical method. Finite element analysis using LISA free source software was validate by the elasticity theoritical results. It was found that finite element analysis stress concentration factor results shows similar pattern as theoretical but higher near of the hole. Plain strain analysis with Quad 8 element type showed better results compared to plain stress with Quad 4 element type and plain strain with Quad 4 element type
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Brian Clegg, Mining The Internet — Information Gathering and Research on the Net, Kogan Page: London, 1999. ISBN: 0–7494–3025–7. Paperback, 147 pages, £9.99
Automating embedded analysis capabilities and managing software complexity in multiphysics simulation part I: template-based generic programming
An approach for incorporating embedded simulation and analysis capabilities
in complex simulation codes through template-based generic programming is
presented. This approach relies on templating and operator overloading within
the C++ language to transform a given calculation into one that can compute a
variety of additional quantities that are necessary for many state-of-the-art
simulation and analysis algorithms. An approach for incorporating these ideas
into complex simulation codes through general graph-based assembly is also
presented. These ideas have been implemented within a set of packages in the
Trilinos framework and are demonstrated on a simple problem from chemical
engineering
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Understanding construction delay analysis and the role of pre-construction programming
Copyright © 2013, American Society of Civil Engineers. This is the author's accepted manuscript. The final published article is available from the link below.Modern construction projects commonly suffer from delay in their completions. The resolution of time and cost claims consequently flowing from such delays continues to remain a difficult undertaking for all project parties. A common approach often relied on by contractors and their employers (or their representatives) to resolve this matter involves applying various delay analysis techniques, which are all based on construction programs originally developed for managing the project. However, evidence from literature suggests that the reliability of these techniques in ensuring successful claims resolution are often undermined by the nature and quality of the underlying program used. As part of a wider research carried out on delay and disruption analysis in practice, this paper reports on an aspect of the study aimed at exploring preconstruction stage programming issues that affect delay claims resolutions. This aspect is based on an in-depth interview with experienced construction planning engineers in the United Kingdom, conducted after an initial large-scale survey on delay and disruption techniques usage. Summary of key findings and conclusions include: (1) most contractors prefer to use linked bar chart format for their baseline programs over conventional critical path method (CPM) networks; (2) baseline programs are developed using planning software packages. Some of these pose difficulties when employed for most delay analysis techniques, except for simpler ones; (3) manpower loading graphs are not commonly developed as part of the main deliverables during preconstruction stage planning. As a result, most programs are not subjected to resource loading and leveling for them to accurately reflect planned resource usage on site. This practice has detrimental effects on the reliability of baseline programs in their use for resolving delay claims; and (4) baseline program development involves many different experts within construction organizations as expected, but with very little involvement of the employer or its representative. Active client involvement is however quite important as it would facilitate quick program approval/acceptance before construction, a necessary requirement for early delay claims settlement, which otherwise are often left unresolved long after the delaying events with the potential of generating into expensive disputes. The study results provide a better understanding of the key issues that need attention if improvements are to be made in delay claim resolutions. Additional research focusing on the testing of these results using a much larger sample and rigorous statistical analysis for generalization purposes would be helpful in advancing the limited knowledge of this subject matter
Modelling an End to End Supply Chain system Using Simulation
Within the current uncertain environment industries are predominantly faced with various challenges
resulting in greater need for skilled management and adequate technique as well as tools to manage
Supply Chains (SC) efficiently. Derived from this observation is the need to develop a generic/reusable
modelling framework that would allow firms to analyse their operational performance over time (Mackulak
and Lawrence 1998, Beamon and Chen 2001, Petrovic 2001, Lau et al. 2008, Khilwani et al. 2011, Cigollini et
al. 2014). However for this to be effectively managed the simulation modelling efforts should be directed
towards identifying the scope of the SC and the key processes performed between players.
Purpose: The research attempts to analyse trends in the field of supply chain modelling using simulation
and provide directions for future research by reviewing existing Operations Research/Operations
Management (OR/OM) literature. Structural and operational complexities as well as different business
processes within various industries are often limiting factors during modelling efforts. Successively, this
calls for the end to end (E2E) SC modelling framework where the generic processes, related policies and
techniques could be captured and supported by the powerful capabilities of simulation.
Research Approach: Following Mitroff’s (1974) scientific inquiry model and Sargent (2011) this research will
adopt simulation methodology and focus on systematic literature review in order to establish generic OR
processes and differentiate them from those which are specific to certain industries. The aim of the
research is provide a clear and informed overview of the existing literature in the area of supply chain
simulation. Therefore through a profound examination of the selected studies a conceptual model will be
design based on the selection of the most commonly used SC Processes and simulation techniques used
within those processes. The description of individual elements that make up SC processes (Hermann and
Pundoor 2006) will be defined using building blocks, which are also known as Process Categories.
Findings and Originality: This paper presents an E2E SC simulation conceptual model realised through
means of systematic literature review. Practitioners have adopted the term E2E SC while this is not
extensively featured within academic literature. The existing SC studies lack generality in regards to
capturing the entire SC within one methodological framework, which this study aims to address.
Research Impact: A systematic review of the supply chain and simulation literature takes an integrated and
holistic assessment of an E2E SC, from market-demand scenarios through order management and planning
processes, and on to manufacturing and physical distribution. Thus by providing significant advances in
understanding of the theory, methods used and applicability of supply chain simulation, this paper will
further develop a body of knowledge within this subject area.
Practical Impact: The paper will empower practitioners’ knowledge and understanding of the supply chain
processes characteristics that can be modelled using simulation. Moreover it will facilitate a selection of
specific data required for the simulation in accordance to the individual needs of the industry
Evaluation of electric and magnetic fields distribution and SAR induced in 3D models of water containers by radiofrequency radiation using FDTD and FEM simulation techniques
In this study, two software packages using different numerical techniques
FEKO 6.3 with Finite-Element Method (FEM) and XFDTD 7 with Finite Difference
Time Domain Method (FDTD) were used to assess exposure of 3D models of square,
rectangular, and pyramidal shaped water containers to electromagnetic waves at
300, 900, and 2400 MHz frequencies. Using the FEM simulation technique, the
peak electric field of 25, 4.5, and 2 V/m at 300 MHz and 15.75, 1.5, and 1.75
V/m at 900 MHz were observed in pyramidal, rectangular, and square shaped 3D
container models, respectively. The FDTD simulation method confirmed a peak
electric field of 12.782, 10.907, and 10.625 V/m at 2400 MHz in the pyramidal,
square, and rectangular shaped 3D models, respectively. The study demonstrated
an exceptionally high level of electric field in the water in the two identical
pyramid shaped 3D models analyzed using the two different simulation
techniques. Both FEM and FDTD simulation techniques indicated variations in the
distribution of electric, magnetic fields, and specific absorption rate of
water stored inside the 3D container models. The study successfully
demonstrated that shape and dimensions of 3D models significantly influence the
electric and magnetic fields inside packaged materials; thus, specific
absorption rates in the stored water vary according to the shape and dimensions
of the packaging materials.Comment: 22 pages, 30 figures and 2 table
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