A Stochastic Approach to Integrated Vehicle Reliability Prediction

2009 ◽  
Author(s):  
Justin Madsen ◽  
Dan Ghiocel ◽  
David Gorsich ◽  
David Lamb ◽  
Dan Negrut
Keyword(s):  
Integrated Approach ◽  
Stochastic Approach ◽  
Reliability Prediction ◽  
Operational Environment ◽  
Research Project ◽  
Element Analysis ◽  
Ground Vehicle ◽  
Us Army ◽  
University Of Wisconsin ◽  
Prediction Approach

This paper addresses some aspects of an on-going multiyear research project of GP Technologies in collaboration with University of Wisconsin-Madison for US Army TARDEC. The focus of this research project is to enhance the overall vehicle reliability prediction process. A combination of stochastic models for both the vehicle and operational environment are utilized to determine the range of the system dynamic response. These dynamic results are used as inputs into a finite element analysis of stresses on subsystem components. Finally, resulting stresses are used for damage modeling and life and reliability predictions. This paper describes few selected aspects of the new integrated ground vehicle reliability prediction approach. The integrated approach combines the computational stochastic mechanics predictions with available statistical experimental databases for assessing vehicle system reliability. Such an integrated reliability prediction approach represents an essential part of an intelligent virtual prototyping environment for ground vehicle design and testing.

US Army Ground Vehicle Crew Compartment Halon Replacement Program

2000 ◽  
Author(s):  
Mike Clauson ◽  
Steve McCormick ◽  
Hal Cross
Keyword(s):  
Ground Vehicle ◽  
Us Army ◽  
Halon Replacement

Tolerance Analysis and Synthesis for Composite Assemblies of Resin Transfer Molded Components

Manufacturing ◽  
2003 ◽  
Author(s):  
Chensong Dong ◽  
Chuck Zhang ◽  
Zhiyong Liang ◽  
Ben Wang
Keyword(s):  
Composite Structures ◽  
Dimensional Accuracy ◽  
Tolerance Analysis ◽  
Process Models ◽  
Design Parameters ◽  
Element Analysis ◽  
Control Dimension ◽  
And Control ◽  
Prediction Approach ◽  
Variation Model

With the increasing demand for composite products to be affordable, net-shaped and efficiently assembled, tight dimension tolerance is critical. Due to lack of accurate process models, dimension analysis and control for resin transfer molding (RTM) processes are often performed using trial-and-error approaches based on engineers’ experiences or previous production data. Such approaches are limited to specific geometry and materials and often fail to achieve the required dimensional accuracy in the final products. This paper presents an innovative dimension variation prediction approach. First a dimension variation model was developed based on process simulation, the classical laminate theory (CLT) and finite element analysis (FEA). The FEA-based dimension variation model was validated against experimental data. The deformations of common features in typical composite structures were analyzed using the FEA-based dimension variation model. Design parameters were identified and the regression-based dimension variation model was developed. The model provides a fast, practical and proactive tool to predict and control dimension variations in RTM processes. The structural tree method (STM) is presented for design optimization and tolerance analysis/synthesis of composite assemblies.

FEA Based Simplified Integrated Analysis for Mudmat Design

2019 ◽  
Author(s):  
Srikanth Srigiriraju ◽  
Arindam Chakraborty ◽  
Burak Ozturk ◽  
Devvrat Rathore
Keyword(s):  
Traditional Approach ◽  
Limit Equilibrium ◽  
Integrated Approach ◽  
American Petroleum Institute ◽  
Integrated Analysis ◽  
Element Analysis ◽  
Simplified Approach ◽  
Artificial Boundary Conditions ◽  
Limit Equilibrium Methods ◽  
Fea Model

Abstract The objective of this study is to explore the opportunity to improve the design and sizing of mudmat for subsea structures, such as Pipeline End Termination (PLET). This is done by comparing the traditional approach following the limit equilibrium methods in API RP 2GEO with a more rigorous simplified integrated analysis approach that involves a single finite element analysis (FEA) model that includes both the pipeline and jumpers together along with the soil-mudmat interaction modeled as non-linear springs, and to quantify any conservatism inherent in the traditional approach. A mudmat design with aspect ratio of 1:2 was considered for detailed analysis. Initially, jumper and pipeline loads were determined by imposing artificial boundary conditions at the hubs and end terminals. Using analytical methods and considering a total dead (submerged) weight of the mudmat and superstructure, a mudmat size was determined per the American Petroleum Institute (API) approach. Factor of Safety (FOS) for bearing and sliding loads were also determined. Thereon, using this mudmat size, the FOS for bearing and sliding were determined using the simplified integrated approach with nonlinear springs representing soil-mudmat interactions. The FOS values using the simplified approach were observed to be higher than those obtained using the traditional approach. This provides an opportunity for a “leaner” design, especially as new high pressure, high temperature (HPHT) fields are made feasible where the mudmat size, if designed with conservatism in API RP 2GEO, may be impractically large for installation.

Predictive Residual Ovality for Reel-Laid Pipelines in Deepwater

2015 ◽  
Author(s):  
T. Sriskandarajah ◽  
Venu Rao
Keyword(s):  
Finite Element ◽  
Limit State ◽  
Accurate Determination ◽  
Integrated Approach ◽  
External Pressure ◽  
Full Scale ◽  
Finite Element Analyses ◽  
Element Analysis ◽  
Laser Measurements ◽  
Numerical Finite Element

Accurate determination of residual ovality is an important parameter for a successful deployment of single pipeline and pipe-in-pipe in deep waters wherein the integrity of empty pipes during installation depends upon the collapse resistance under external hydrostatic pressure. The reel-lay process of installation during which pipeline undergoes multiple strain cycles due to spooling, reeling and straightening has a significant bearing on pipe ovalisation and hence accurate determination residual ovality at the end of straightening process is one of the key inputs. It is industry practice to use numerical finite element analysis techniques to predict residual ovality of pipelines as full scale testing is expensive and time consuming. In view of the importance of residual ovality on the pipeline integrity particularly for deepwater applications, an integrated approach of testing and finite element simulation have been used to identify the correct numerical model that predicts residual ovality accurately. This paper discusses the full scale tests performed which include material testing and bend tests performed to simulate spooling and straightening process and the pipeline deformations recorded using laser measurements at different cycles of bending process. The paper presents a brief summary of numerical finite element analyses performed to validate the test results and the effect of element types and material models used in the finite element analyses on the predictability of residual ovality. The material evolution models and their effect on the predictability of remaining ovality are discussed in the paper. Comparisons are made on the predictive residual ovality for reel lay process on single pipe and pipe-in-pipe. The effect of residual ovality on the pipeline integrity for the lateral buckling limit state under combined bending and external pressure are discussed in the paper.

Using High-Resolution Digital Scans in Multimedia Cartographic Applications

1994 ◽  
pp. 26-30
Author(s):  
David W. Tilton
Keyword(s):  
Native American ◽  
High Resolution ◽  
Research Project ◽  
Cd Rom ◽  
University Of Wisconsin ◽  
The Creation ◽  
Scanned Images ◽  
The University

Since June of 1993, the Geography Department at the University of Wisconsin-Milwaukee has been engaged in a research project to develop the Archive of Native American Maps on CD-ROM. A major component of this project involves the creation of high-resolution scans of the maps in the archive. This paper discusses several issues encountered in the acquisition, manipulation and display of these scanned images. The issues include scanning resolution, file compression, palette shifts, and image tiling.

The climatic influence on sustainable refurbishments and life cycle investing in Australia

2015 ◽  
Vol 33 (1) ◽  
pp. 19-35
Author(s):  
Chris Heywood ◽  
Eckhart Hertzsch ◽  
Mirek Piechowski
Keyword(s):  
Life Cycle ◽  
Asset Management ◽  
Net Present Value ◽  
Capital Expenditure ◽  
Ghg Emissions ◽  
Integrated Approach ◽  
Building Envelope ◽  
Research Project ◽  
Content Type ◽  
The Impact

Purpose – The purpose of this paper is to report an investigation of the effect of location on refurbishment strategies to reduce greenhouse gas (GHG) emissions using the temperate and sub-tropical urban locations in Australia. This occurred within a larger research project that investigated methods for sustainable refurbishments to office buildings and their optimized timing from an investment perspective. Design/methodology/approach – An office building in Melbourne was used to develop seven sets of improvements using an integrated approach to upgrade mechanical services and the building envelope. Using asset management trigger points the impact on net present value and internal rate of return were calculated, taking into account the capital expenditure required, the energy savings due to the refurbishment, as well as a possible rental increase due to the upgrade and lesser operational energy bills for the tenants. To investigate the importance of the location attribute the upgraded building’s performance was modelled in a different climate by using a Brisbane weather file. Findings – A number of unexpected results were found, including that the same sets of improvements had similar reductions in GHG emissions in the two locations, they had similar impacts on the investment criteria and when using the National Australian Building Energy Rating System it was shown that it was easier and cheaper to get an uplift in stars in Melbourne than Brisbane. Research limitations/implications – This location-specific analysis is the result of using a more sophisticated and holistic methodology to analyse sustainable refurbishments that more closely resembles the complexity of the decision making required to make buildings more sustainable. Practical implications – This paper provides a basis for property investors to make decisions about sustainable investments when location is important. This can occur when a portfolio is distributed across various climate zones. Originality/value – The research project that the paper reports addresses the complexity of building attributes, possible sets of improvements to reduce GHG emissions and their investment decisions, within a life cycle view of assets. It is rare that this complexity is addressed as a whole, and rarer that locational climatic differences are examined.

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