scholarly journals Simulation-driven product development of cast components with allowance for process-induced material behaviour

2020 ◽  
Vol 7 (1) ◽  
pp. 78-85
Author(s):  
J Jansson ◽  
J Olofsson ◽  
K Salomonsson
Keyword(s):  
Residual Stresses ◽  
Finite Element Analyses ◽  
Material Behaviour ◽  
Large Magnitude ◽  
Strength Differential ◽  
Design Engineers ◽  
Process Simulations ◽  
Specific Material ◽  
And Performance ◽  
Complex Relationships

Abstract This paper presents a methodology that can be used to consider local variations in thermomechanical and thermophysical material properties, residual stresses, and strength-differential effects in finite element analyses of cast components. The methodology is based on applying process simulations and structural analyses together with experimentally established, or already available literature data, in order to describe element-specific material variations. A cast-iron cylinder head was used in order to evaluate the influence of several simplifications that are commonly performed in computer aided engineering. It is shown that non-trivial errors of a potentially large magnitude are introduced by not considering residual stresses, compressive behaviour, temperature dependence, and process-induced material property variations. By providing design engineers with tools that allow them to consider the complex relationships between these aspects early in the development phase, cast components have the potential to be further optimized with respect to both weight and performance.

Crack Initiation in Railway Wheels Resulting From Rolling Contacts

2011 ◽  
Author(s):  
Steven L. Dedmon ◽  
Huseyin Guzel
Keyword(s):  
Crack Initiation ◽  
Residual Stresses ◽  
Cold Work ◽  
Finite Element Analyses ◽  
Metallic Inclusion ◽  
Destructive Testing ◽  
Rolling Contacts ◽  
Complex Relationships ◽  
Property Changes ◽  
Railway Wheels

Classic shelling of a railway wheel begins with crack initiation resulting from wheel rail interactions. This investigation shows the complex relationships that occur between contact stress, cold work, residual stresses, and temperatures from brake heating and non-metallic inclusion types which can lead to the formation of shelling cracks. Our investigation also includes an explanation of how these interactions affect mechanical properties such as yield strength, elastic modulus, and ductility. In turn, mechanical property changes also affect how cold work and its associated residual stresses develop under cyclic loading. Destructive testing and Finite Element Analyses were used in support of this work.

Fatigue analysis of rolled components considering transient cyclic material behaviour and residual stresses

2018 ◽  
Vol 13 (2) ◽  
pp. 189-200 ◽  
Author(s):  
David Kühne ◽  
Christina Guilleaume ◽  
Martha Seiler ◽  
Peter Hantschke ◽  
Franz Ellmer ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Fatigue Analysis ◽  
Material Behaviour

VIV Predictions for an SCR in Sheared Ocean Currents

2002 ◽  
Author(s):  
Christopher J. Wajnikonis
Keyword(s):  
Experimental Data ◽  
Design Parameters ◽  
Finite Element Analyses ◽  
Steel Catenary Riser ◽  
Specialized Software ◽  
Design Engineers ◽  
Sensitivity Studies ◽  
Deepwater Riser ◽  
Extended Program ◽  
Areas Of Interest

Vortex Induced Vibration (VIV) prediction is one of the key areas of interest in Deepwater Riser Engineering. Several Joint Industry Projects (JIPs) are currently in progress in this field, which results in an increase of experimental data available to design engineers, in revisions of specialized software and in development of new engineering tools. This paper presents VIV predictions for a hypothetical Steel Catenary Riser (SCR) using the latest versions of the SHEAR7 and the VIVA/VIVARRAY Programs. Both built-in and extended program capabilities are utilized and detailed plots of computation results are presented. Sensitivity studies on the influence of variations of selected design parameters are also included in the paper. Finite Element Analyses (FEAs) results and simple engineering tools were utilized in parallel to built-in program features. The calculations demonstrated, that for the riser investigated and presumably also for a wide variety of similar SCRs, that the built in program features are sufficient to predict VIVs conservatively. Notes on VIV predictions in a real ocean and on selected areas that require investigation are also included.

A Simple Approach for Including Weld Residual Stresses in the Calculation of Pipe Circumferential Through-Wall Crack Opening Displacements

2016 ◽  
Author(s):  
Richard Olson
Keyword(s):  
Residual Stresses ◽  
Axial Force ◽  
Analytic Solution ◽  
Crack Opening ◽  
Bending Moment ◽  
Generalized Solution ◽  
Finite Element Analyses ◽  
Opening Displacement ◽  
Crack Face ◽  
Basic Equations

Current methodologies for predicting the crack opening displacement (COD) of circumferentially through-wall cracked pipe do not include the effect of weld residual stresses (WRS). Even the most advanced COD prediction methodology only includes the effect of applied axial force, bending moment, and crack face pressure. For some years, it has been known that weld residual stresses do alter the COD, but there has been no convenient way to include them in a COD prediction without doing case-specific finite element analyses. This paper documents a generalized solution for including WRS effects on COD. The model uses a closed-form analytic solution to approximate the crack face rotations that the WRS would induce which, subsequently, can be added to the typical axial force-bending-crack face pressure COD solution. The methodology is described and the basic equations for the solution are presented. Following this, application to cases to evaluate the efficacy of the approach are presented which show a mixture of results ranging from amazingly good to “of questionable value” with respect to the FEA results.

Performance Degradation Detection of Virtual Machines Via Passive Measurement and Machine Learning

2014 ◽  
Vol 5 (2) ◽  
pp. 40-56 ◽  
Author(s):  
Toshiaki Hayashi ◽  
Satoru Ohta
Keyword(s):  
Machine Learning ◽  
Virtual Machines ◽  
Performance Degradation ◽  
Training Data ◽  
Efficient Operation ◽  
Traffic Measurement ◽  
Passive Measurement ◽  
And Performance ◽  
Complex Relationships ◽  
Heavy Loads

Virtualization is commonly used for efficient operation of servers in datacenters. The autonomic management of virtual machines enhances the advantages of virtualization. Therefore, for the development of such management, it is important to establish a method to accurately detect the performance degradation in virtual machines. This paper proposes a method that detects degradation via passive measurement of traffic exchanged by virtual machines. Using passive traffic measurement is advantageous because it is robust against heavy loads, non-intrusive to the managed machines, and independent of hardware/software platforms. From the measured traffic metrics, performance state is determined by a machine learning technique that algorithmically determines the complex relationships between traffic metrics and performance degradation from training data. The feasibility and effectiveness of the proposed method are confirmed experimentally.

Analyze Physical Design Process Using Big Data Tool

2015 ◽  
Vol 7 (2) ◽  
pp. 31-49 ◽  
Author(s):  
Waseem Ahmed ◽  
Lisa Fan
Keyword(s):  
Design Process ◽  
Data Extraction ◽  
Daily Basis ◽  
Physical Design ◽  
Data Repository ◽  
Chip Design ◽  
Asic Design ◽  
Design Engineers ◽  
Statistical Representation ◽  
And Performance

Physical Design (PD) Data tool is designed mainly to help ASIC design engineers in achieving chip design process quality, optimization and performance measures. The tool uses data mining techniques to handle the existing unstructured data repository. It extracts the relevant data and loads it into a well-structured database. Data archive mechanism is enabled that initially creates and then keeps updating an archive repository on a daily basis. The logs information provide to PD tool is a completely unstructured format which parse by regular expression (regex) based data extraction methodology. It converts the input data into the structured tables. This undergoes the data cleansing process before being fed into the operational DB. PD tool also ensures data integrity and data validity. It helps the design engineers to compare, correlate and inter-relate the results of their existing work with the ones done in the past which gives them a clear picture of the progress made and deviations that occurred. Data analysis can be done using various features offered by the tool such as graphical and statistical representation.

scholarly journals Dancing in the 'Contact Zone'

2006 ◽  
Vol 3 (2) ◽  
Author(s):  
Monica Wulff
Keyword(s):  
Contact Zone ◽  
The West ◽  
Cultural Encounters ◽  
Performance Space ◽  
Arts Festival ◽  
And Performance ◽  
Complex Relationships ◽  
Multicultural Arts ◽  
Embodied Practice

In October 2002 I performed and exhibited Troppo Obscura: A Peepshow of Historical Perversity at the Performance Space as part of the multicultural Arts festival, Carnivale, in Sydney, Australia. Troppo Obscura is a multimedia installation that explores some aspects of the complex relationships between the West and Asia. The work looks at a large range of possibilities, from the colonial gaze through to personal relationships forged through artistic endeavor. This paper—the first of two extended mediations on the topic—focuses on one such personal relationship addressed in the installation, namely that between traditional master mask dancer Ibu Sawitri from Cirebon on the West coast of Java, Indonesia and myself, a Sydney based contemporary dancer and performance artist. Between 1992 and 1999, the year Ibu Sawitri passed away, I spent many long-term visits learning dance and living in Ibu Sawitri’s house in Losari. This essay focuses on Ibu Sawitri’s family and dance background and how she, the younger generation of dancers, the dance context, and the dance itself, have been transformed over time as a result of rapidly changing socio-historical conditions. In the second half of this paper I move the discussion to the broader issues of cross-cultural encounters in what Pratt terms the ‘contact zone’ (1992). This includes looking at dance as an embodied practice and its function in the ‘contact zone’ as well as dealing with Spivak’s debates about the subaltern voice in reference to my telling of Ibu Sawitri’s story, both in the installation and in text. A closer analysis of the dynamics of my dance with Ibu Sawitri in the ‘contact zone’ is addressed here.

Estimation of Stress Intensity Factors due To Welding Residual Stresses for Circumferentially Cracked Pipes

2012 ◽  
Author(s):  
Chang-Young Oh ◽  
Ji-Soo Kim ◽  
Yun-Jae Kim ◽  
Young-Jin Oh ◽  
Kyoungsoo Lee ◽  
...  
Keyword(s):  
Finite Element ◽  
Stress Intensity ◽  
Residual Stresses ◽  
Stress Intensity Factors ◽  
Finite Element Analyses ◽  
Intensity Factors ◽  
Crack Face ◽  
Simple Method ◽  
Weld Geometry ◽  
Nonlinear Stress

This paper proposes a simple method to estimate stress intensity factors due to welding residual stresses. In this study, finite element analyses for circumferentially cracked pipe are performed to calculate stress intensity factors. Four cracked geometries and two types of weld geometry are considered. KI-solutions for the nonlinear stress distribution on the crack face were determined in accordance with codes and standards. The results are compared with KI-solutions from finite element results. It is found that proposed simple method agrees well with FE results.

The Effect of Modelling Simplifications on the Prediction of Residual Stresses in a Multi-Pass Plate Groove Weld

2007 ◽  
Author(s):  
A. P. Warren ◽  
S. K. Bate ◽  
P. Hurrell
Keyword(s):  
Finite Element ◽  
Heat Source ◽  
Residual Stresses ◽  
Finite Element Analyses ◽  
Computational Power ◽  
Test Pieces ◽  
Single Bead ◽  
Welding Processes

The inherent complexity of modelling welding processes and the lack of computational power available to analysts have resulted in simplified methods being commonly utilised when predicting residual stresses in welded components. Despite considerable advances in computational power, it is still often not possible to run detailed 3D analyses of complex welded geometries within practical timescales. Against this background, a programme of work has been undertaken in order to investigate the effect these simplifications will have on the prediction of residual stresses on a number of test-pieces. The geometry investigated in this paper is a plate containing a “V” groove, which runs the length of the plate and is filled with eight mechanised TIG weld passes. This paper presents the results of a number of finite element analyses conducted of this geometry. The analyses presented have been conducted using the commercial finite element packages SYSWELD and ABAQUS, using a number of modelling simplifications. These simplifications include modelling the plate in 2D and the use of the bead lumping technique to idealise a number of beads as a single bead. Also considered are various methods of heat source representation, namely; a moving ellipsoidal heat source, prescribed temperature and block dumping. These analyses are compared and qualitative conclusions are drawn.

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