scholarly journals Thermal Cracks Development Study in Newly Built Reinforced Concrete Residences

2021 ◽  
Vol 1203 (2) ◽  
pp. 022036
Author(s):  
Hymabaccus El Fez Hashmi ◽  
Seeboo Asish

Abstract Concrete blocks and concrete assemblies are affected by natural physical conditions, which impacts on the durability and service life of the structures. In this paper, site data was gathered, which was used to perform a numerical and a finite element modelling to investigate the impacts of several conditions on thermal cracking in a structure. The field recorded data was used for the numerical modelling, using MATLAB software, and the finite element modelling, using ANSYS Mechanical software. It was observed that among the conditions considered, the wall ratio in the structure and formation of microcracks have significant impacts, while the age of the structure, the compressive strength of the concrete have minimal impacts, as the shifting in the curve is small. Finally, a probabilistic crack development model was made to study the potential crack development in the finite element model, which was seen to tally with observed site data, demonstrating the potential of predicting cracks development.

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.


Author(s):  
Yongtao Lu ◽  
Zhuoyue Yang ◽  
Yongxuan Wang

Compression therapy is an adjuvant physical intervention providing the benefits of calibrated compression and controlled stretch and consequently is increasingly applied for the treatment of chronic venous insufficiency. However, the mechanism of the compression therapy for chronic venous insufficiency is still unclear. To elaborate the mechanism of compression therapy, in recent years, the computational modelling technique, especially the finite element modelling method, has been widely used. However, there are still many unclear issues regarding the finite element modelling of compression therapy, for example, the selection of appropriate material models, the validation of the finite element predictions, the post-processing of the results. To shed light on these unclear issues, this study provides a state-of-the-art review on the application of finite element modelling technique in the compression therapy for chronic venous insufficiency. The aims of the present study are as follows: (1) to provide guidance on the application of the finite element technique in healthcare and relevant fields, (2) to enhance the understanding of the mechanism of compression therapy and (3) to foster the collaborations among different disciplines. To achieve these aims, the following parts are reviewed: (1) the background on chronic venous insufficiency and the computational modelling approach, (2) the acquisition of medical images and the procedure for generating the finite element model, (3) the definition of material models in the finite element model, (4) the methods for validating the finite element predictions, (5) the post-processing of the finite element results and (6) future challenges in the finite element modelling of compression therapy.


2015 ◽  
Vol 74 (4) ◽  
Author(s):  
Mariyana A. A. K. ◽  
A. S. M. Abdul Awal ◽  
Mahmood Md. Tahir

This paper presents finite element modelling (FEM) of a reinforced concrete (RC) frame subjected to elevated temperature. The work presented is part of the UK-India Education and Research Initiative (UKIERI) project. In this project, an experimental test of sub-assemblage frame with elevated temperature has been performed at Indian Institute of Technology (IIT) Roorkee, India. The finite element model using ABAQUS software has been used to validate the increased in temperature distribution on reinforced concrete frame exposed to fire. The idea of this study is to design a compartment fire, and determination of emissivity value at different height. And composition of hot gases was calculated. Gas temperatures used was based on the average temperature-curve obtained in the fire test. The validity of the finite element model was established by comparing the predicted values from the FEM with test data direct from fire test results. The results obtained indicate that suggested FEM analysis procedure is capable of modelling temperature in compartment fires.  


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.


2014 ◽  
Vol 553 ◽  
pp. 769-773 ◽  
Author(s):  
E.A. Flores-Johnson ◽  
J.G. Carrillo ◽  
R.A. Gamboa ◽  
Lu Ming Shen

In this work, a 3D finite-element model of the ballistic impact of a multi-layered plain-woven aramid fabric style 720 (Kevlar®129 fibre, 1420 denier, 20×20 yarns per inch) impacted by a 6.7-mm spherical projectile was built at the mesoscale in Abaqus/Explicit by modelling individual crimped yarns. Material properties and yarn geometry for the model were obtained from reported experimental observations. An orthotropic elastic model with a failure criterion based on the tensile strength of the yarns was used. Numerical predictions were compared with available experimental data. It was found that the finite-element model can reproduce the physical experimental observations, such as the straining of primary yarns and pyramidal-shaped deformation after perforation. The permanent deformation of fabric targets predicted by the numerical simulations was compared with available experimental results. It was found that the model fairly predicted the permanent deformation with a difference of about 21% when compared with experiments.


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.


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.


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