scholarly journals Development of Finite Element Model for the Control of Solidification Shrinkage in Al-Si (A8011) Alloy Castings

2020 ◽  
Vol 4 (3) ◽  
Author(s):  
Olusanya Francis Dacosta ◽  
Samuel B Adejuyigbe ◽  
Bayode Olorunfemi ◽  
Adefemi Adekunle

The objective of this research work is to determine a realistic way of minimizing shrinkage in Aluminium-Silicon (Al-Si) alloy castings using finite element modelling. Finite Element method was used to discretize and solve the governing equations developed for the models using the commercial software, Comsol Multi-Physics. The models developed were validated from experimental data obtained from the foundry using six samples which were used to study the temperature profiles and nature of the solidification of the alloys. A comparison of the temperature profiles generated from the experiments and simulations show that in 64% of the processes, there were no significant differences between the experimental and simulated values. In comparing the Niyama values obtained from the experiments and those from the simulations, there were no significant differences in 46% of the processes. Threshold Niyama values of 0.143 (°C-s)1/2/mm was also established. Below these threshold values, it is predicted that shrinkage will occur in castings from these metals.Keywords— Aluminium alloy, Al-Si (A8011), Castings, Finite Element, Shrinkage, Solidification

2014 ◽  
Vol 657 ◽  
pp. 735-739 ◽  
Author(s):  
Emilian Ionut Croitoru ◽  
Gheorghe Oancea

This paper presents a method of finite element modelling used for the impact analysis of a composite panel. In this research, the composite panel consists of an oxygen mask locking panel of an aircraft. This panel is loaded with one concentrated abuse loading and three uniform distributed abuse loading cases and the stress variation within the composite panel for each load case is determined. In order to assess the impact analysis on the oxygen mask panel of the aircraft, a finite element model is created using Patran as the main application for pre/post-processing and Nastran as the main processor. The paper also presents a comparison between results obtained using the same finite element modelling of the composite panel CAD model of the panel with four load cases with different material types. The results are used to determine the most capable material stresswise.


Author(s):  
Martin Pletz ◽  
Werner Daves ◽  
Heinz Ossberger

A finite element model for the process of a wheel passing a crossing is presented. In the dynamic model, one wheel, the wing rails and the crossing nose (frog) are modelled. The bogie, the complete wheel set and the support of the crossing are represented as a system consisting of masses, springs, dampers and friction-generating elements. The rolling/sliding behaviour between the wheel and crossing is studied using the proposed model. Due to the conical shape of the wheel tread and multiple contacts between the wheel and the crossing parts, sliding occurs during the transition of the wheel from the wing rail to the crossing nose or vice versa. At the same time, an impact occurs that produces high contact forces. The parameters of the model are the train speed and passing direction, the wheel and the crossing geometry, the axle load and the support of the crossing. In this paper, the crossover process is studied for high axle loads and compared with results of simulations using a normal axle load. Further parameters are three train velocities, both directions of passing and different crossing materials. The loading of the crossing nose is calculated for all cases (axle load, train speed and direction) and materials.


2011 ◽  
Vol 2 (3) ◽  
pp. 416-423
Author(s):  
K. De Keyser ◽  
F. Van Acker ◽  
Stijn Hertelé ◽  
Matthias Verstraete ◽  
Wim De Waele ◽  
...  

To investigate the influence of global plastic deformations on girth weld defect tolerance inpipelines, a parametric finite element model has been developed. This paper provides an experimentalvalidation of the model. It describes the test setup and instrumentation used for the evaluation of plasticstrain fields around a notch in a tension loaded non-welded X65 mini wide plate. LVDT measurements anddigital image correlation (DIC) results are compared to each other and to the results of finite elementsimulations. Whereas some deviation is observed owing to unavoidable experimental uncertainties andlimitations of finite element modelling, the overall correspondence is more than satisfying.


2022 ◽  
Vol 7 (1) ◽  
pp. 8
Author(s):  
Thomas Sharry ◽  
Hong Guan ◽  
Andy Nguyen ◽  
Erwin Oh ◽  
Nam Hoang

As important links in the transport infrastructure system, cable-stayed bridges are among the most popular candidates for implementing structural health monitoring (SHM) technology. The primary aim of SHM for these bridges is to ensure their structural integrity and satisfactory performance by monitoring their behaviour over time. Finite element (FE) model updating is a well-recognised approach for SHM purposes, as an accurate model serves as a baseline reference for damage detection and long-term monitoring efforts. One of the many challenges is the development of the initial FE model that can accurately reflect the dynamic characteristics and the overall behaviour of a bridge. Given the size, slenderness, use of long cables, and high levels of structural redundancy, precise initial models of long-span cable-stayed bridges are desirable to better facilitate the model updating process and to improve the accuracy of the final updated model. To date, very few studies offer in-depth discussions on the modelling approaches for cable-stayed bridges and the methods used for model updating. As such, this article presents the latest advances in finite element modelling and model updating methods that have been widely adopted for cable-stayed bridges, through a critical literature review of existing research work. An overview of current SHM research is presented first, followed by a comprehensive review of finite element modelling of cable-stayed bridges, including modelling approaches of the deck girder and cables. A general overview of model updating methods is then given before reviewing the model updating applications to cable-stayed bridges. Finally, an evaluation of all available methods and assessment for future research outlook are presented to summarise the research achievements and current limitations in this field.


Buildings ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 5
Author(s):  
Madhushan Dissanayake ◽  
Thadshajini Suntharalingam ◽  
Konstantinos Daniel Tsavdaridis ◽  
Keerthan Poologanathan ◽  
Gatheeshgar Perampalam

The use of 3D printing in modular building connections is a novel and promising technique. However, the performance of 3D printed steel modular building connections has not been investigated adequately to date. Therefore, this paper presents a three-dimensional finite element model (FEM), using the multi-purpose software Abaqus, to study the effect of different geometrical and material parameters on the ultimate behaviour of modular building connections (herein named 3DMBC) using a wire and arc additive manufacturing (WAAM) method, as part of the UK’s 3DMBC (3D Modular Building Connections) project. The proposed model considers material and geometrical non-linearities, initial imperfections, and the contact between adjacent surfaces. The finite element results are compared with the currently available experimental results and validated to ensure developed FEM can be used to analyse the behaviour of 3DMBC with some adjustments. Case studies were investigated using the validated model to analyse the ultimate behaviour with different nominal and WAAM-produced materials under various loading arrangements. Based on the results, it is recommended to conservatively use the treated or untreated WAAM material properties obtained in θ = 90° print orientation in the finite element modelling of 3DMBCs considering the complex component arrangements and multi-directional loading in the modular connections. It is also noted that the thickness of beams and columns of fully 3D printed connections can be increased to achieve the same level of performance as traditional modular connections. For the 3DMBCs printed using untreated WAAM, the thickness increment was found to be 50% in this study.


Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2332 ◽  
Author(s):  
Alessandro Ruggiero ◽  
Roberto D’Amato ◽  
Saverio Affatato

In biomechanics and orthopedics, finite element modelling allows simulating complex problems, and in the last few years, it has been widely used in many applications, also in the field of biomechanics and biotribology. As is known, one crucial point of FEM (finite element model) is the discretization of the physical domain, and this procedure is called meshing. A well-designed mesh is necessary in order to achieve accurate results with an acceptable computational effort. The aim of this work is to test a finite element model to simulate the dry frictionless contact conditions of a hip joint prosthesis (a femoral head against an acetabular cup) in a soft bearing configuration by comparing the performances of 12 common meshing strategies. In the simulations, total deformation of the internal surface of the cup, contact pressure, and the equivalent von Mises stress are evaluated by using loads and kinematic conditions during a typical gait, obtained from a previous work using a musculoskeletal multibody model. Moreover, accounting for appropriate mesh quality metrics, the results are discussed, underlining the best choice we identified after the large amount of numerical simulations performed.


2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Ameze Big-Alabo

AbstractThe study presents the development of a 3D Finite Element modelling (FEM) technique for a uni-coupled Ge/SiGe superlattice-based module configuration. The methodological approach involved the development of the geometrical design of the Ge/SiGe – based Thermoelectric generator (TEG), defining the thermoelectric material properties and boundary conditions and then implementation of the governing equations to obtain an approximate solution via meshing of the TEG module. The developed FEM was then used to optimize the geometry of the TEG with the aim of reducing the contact resistance for improved performances. One way to achieve this is to reduce the thickness of the silicon substrate. Thus by reducing the thickness of the substrate, the thermal losses in the system will be minimized. Secondly, by increasing the superlattice heights, the output voltage also increased and given the anisotropic nature of the superlattice, it was inferred that the optimal voltage measurements can be obtained at the surface of the superlattice which yields the maximum leg height. The relevance of this study is that the FEM allows the simulation of the TEG module for different real-world conditions that would otherwise be expensive and time-consuming to investigate experimentally. It also gives insight to the temperature and voltage distribution of the TEG module under varying operating conditions.


Holzforschung ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jens U. Hartig ◽  
André Bieberle ◽  
Chris Engmann ◽  
Peer Haller

Abstract In this paper, voxel-based finite element modelling based on spatial geometry and density data is applied to simulate the detailed stress and strain distribution in a large wood element. As example, a moulded wooden tube with a length of 3 m and a diameter of 0.3 m is examined. Gamma-ray computed tomography is used to obtain both, its actual geometric shape and spatial density distribution. Correlation functions (R2 ≈ 0.6) between density and elastic material properties are experimentally determined and serve as link for defining the non-uniform distribution of the material properties in the finite element model. Considering the geometric imperfections and spatial variation of the material properties, a detailed analysis of the stress and strain distribution of a wood element is performed. Additionally, a non-destructive axial compression test is applied on the wooden tube to analyse the load-bearing behaviour. By means of digital image correlation, the deformation of the surface is obtained, which also serves for validation of the finite element model in terms of strain distributions.


2018 ◽  
Vol 17 ◽  
pp. 1
Author(s):  
Jaroslav Čech ◽  
Petr Haušild ◽  
Aleš Materna

Knowledge of the complex deformation behavior in the anisotropic materials is one of essential issues in materials science and it is crucial for the applications of a given material. In this study, mechanical response of Fe3(wt.%)Si single crystal to nanoindentation with spherical indenter was investigated. Hardness and indentation Young´s modulus were determined experimentally and by finite element modelling. Observed pop-in phenomenon, shape of the residual imprints and origin of the slip lines were explained on the basis of resolved shear stress computed by finite element model.


2008 ◽  
Vol 32 ◽  
pp. 251-254 ◽  
Author(s):  
Hei Jie Li ◽  
Jing Tao Han ◽  
Zheng Yi Jiang ◽  
Hua Chun Pi ◽  
Dong Bin Wei ◽  
...  

Taylor-type and finite element polycrstal models have been embedded into the commercial finite element code ABAQUS to carry out the crystal plasticity finite element modelling of BCC deformation texture based on rate dependent crystal constitutive equations. Initial orientations measured by EBSD were directly used in crystal plasticity finite element model to simulate the development of rolling texture of IF steel under various reductions. The calculated results are in good agreement with the experimental values. The predicted and measured textures tend to sharper with an increase of reduction, and the texture obtained from the Taylor-type model is much stronger than that by finite element model. The rolling textures calculated with 48 {110}<110>, {112}<111> and {123}<111> slip systems are close to the EBSD results.


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