Multi-Scale Finite-Element Analysis as a Base for a 3D Computerized Virtual Biopsy System

2008 ◽  
Author(s):  
Lev Podshivalov ◽  
Anath Fischer ◽  
Pinhas Z. Bar-Yoseph
Keyword(s):  
Bone Structure ◽  
Domain Decomposition Method ◽  
Three Dimensional ◽  
Local Solution ◽  
Fe Method ◽  
Element Analysis ◽  
Multi Scale ◽  
Non Invasive ◽  
And Behavior ◽  
Trabecular Bone Tissue

This paper proposes a novel multi-scale approach for three-dimensional non-invasive analysis of 3d bone models reconstructed from μCT/μMRI images. The feasibility of the proposed method is demonstrated on 2D models representing a simple 2D trabecular bone tissue structure. First, a fundamental domain decomposition method is applied to solve these models. Then, a numerical zoom technique is utilized for local solution enhancement. The proposed new multi-scale FE method has the potential to provide new insights into bone structure and behavior as a component of a computerized virtual biopsy system.

Fast Three-Dimensional Finite Element Analysis of Weld Overlay Application on a Formed Feeder Elbow

2011 ◽  
Author(s):  
Francis H. Ku ◽  
Pete C. Riccardella
Keyword(s):  
Residual Stress ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Residual Stresses ◽  
Nuclear Reactor ◽  
Three Dimensional ◽  
Fe Method ◽  
Element Analysis ◽  
Weld Overlay ◽  
Welding Processes

This paper presents a fast finite element analysis (FEA) model to efficiently predict the residual stresses in a feeder elbow in a CANDU nuclear reactor coolant system throughout the various stages of the manufacturing and welding processes, including elbow forming, Grayloc hub weld, and weld overlay application. The finite element (FE) method employs optimized FEA procedure along with three-dimensional (3-D) elastic-plastic technology and large deformation capability to predict the residual stresses due to the feeder forming and various welding processes. The results demonstrate that the fast FEA method captures the residual stress trends with acceptable accuracy and, hence, provides an efficient and practical tool for performing complicated parametric 3-D weld residual stress studies.

scholarly journals Micro- and Nano-Scales Three-Dimensional Characterisation of Softwood

2021 ◽  
Vol 7 (12) ◽  
pp. 263
Author(s):  
Alessandra Patera ◽  
Anne Bonnin ◽  
Rajmund Mokso
Keyword(s):  
Mechanical Response ◽  
Three Dimensional ◽  
Deep Understanding ◽  
Swelling Behaviour ◽  
Multi Scale ◽  
Non Invasive ◽  
X Ray Imaging ◽  
New Findings ◽  
Bordered Pits ◽  
Paul Scherrer

Understanding the mechanical response of cellular biological materials to environmental stimuli is of fundamental importance from an engineering perspective in composites. To provide a deep understanding of their behaviour, an exhaustive analytical and experimental protocol is required. Attention is focused on softwood but the approach can be applied to a range of cellular materials. This work presents a new non-invasive multi-scale approach for the investigation of the hygro-mechanical behaviour of softwood. At the TOMCAT beamline of the Paul Scherrer Institute, in Switzerland, the swelling behaviour of softwood was probed at the cellular and sub-cellular scales by means of 3D high-resolution phase-contrast X-ray imaging. At the cellular scale, new findings in the anisotropic and reversible swelling behaviour of softwood and in the origin of swelling hysteresis of porous materials are explained from a mechanical perspective. However, the mechanical and moisture properties of wood highly depend on sub-cellular features of the wood cell wall, such as bordered pits, yielding local deformations during a full hygroscopic loading protocol.

A Three-Dimensional Finite Element Analysis of Restored Deciduous Canine

2015 ◽  
Vol 638 ◽  
pp. 123-129 ◽  
Author(s):  
Florin Baciu ◽  
Claudia Bratosin ◽  
Aurelia Rusu-Casandra
Keyword(s):  
Finite Element ◽  
Structural Integrity ◽  
Bone Structure ◽  
Three Dimensional ◽  
Medical Problem ◽  
Ct Scanner ◽  
Chronic Infections ◽  
Element Analysis ◽  
Tooth Structure ◽  
Three Dimensional Finite Element

The literature reports that dental cavities are an international public health challenge and treatment of decays especially for young children is a medical problem of great importance. Early childhood caries progress rapidly and can cause functional, physical and dentofacial aesthetic impairment. Recent studies show that caries lesions can compromise children’s quality of life due to the pain and discomfort which could lead to disfigurement, acute and chronic infections and to alteration of meals and sleeping habits. Tooth decay occurs when acids in the mouth dissolve the outer layers of the tooth, stripping the tooth of important minerals. Because dental decay often goes untreated, the cavity grows and more tooth structure is lost. Restorative dentistry has the main purpose of rehabilitating the function and aesthetic of tooth. The structural integrity of the restored teeth depends on the state of stress in their different regions due to occlusal loads. The aim of this study performed with the finite element method is to evaluate the stress and strain distributions in bone structure-primary canine-restorative material assembly when a load of 120N is applied all over the upper surface of the model. Particular attention was given to an accurate computer reconstruction of the canine. Therefore with the aid of a CT scanner the tomography images obtained were processed with a special software (Mimics). Two dental restorative materials, commonly used in practice were chosen for the analysis and the results acquired are compared. Also the contact pressure at the interface bone-deciduous canine and deciduous canine-dental material is evaluated in both cases.

Deformation Behavior Analysis of Harmonic Structure Materials by Multi-Scale Finite Element Analysis

2015 ◽  
Vol 1088 ◽  
pp. 853-857 ◽  
Author(s):  
Han Yu ◽  
Ikumu Watanabe ◽  
Kei Ameyama
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Model Material ◽  
Structure Design ◽  
Coarse Grained ◽  
Harmonic Structure ◽  
Element Analysis ◽  
Multi Scale ◽  
Microscopic Deformation

The harmonic structure materials consist of coarse-grained areas enclosed in a three-dimensional continuously connected network of ultrafine-grained area. The concept of harmonic structure design has been successfully applied to a variety of pure metals and alloys by mechanical milling (MM) and subsequent powder metallurgy (PM) process. In harmonic structure material, core region with coarse grains maintains a high ductility while the shell region with ultrafine grains contributes for a higher strength. Therefore, the material with harmonic structure design can achieve both strength and ductility simultaneously. In this research, the SUS304L grade stainless steel has been used as a model material to understand and validate the response of the harmonic structure materials towards the applied external loads. The numerical simulation of multi-scale FEA (Finite Element Analysis) was carried out, and it was confirmed that microscopic deformation and the macroscopic tensile strength can be characterized by the present approach.

Biomimetic Design of Lightweight Vehicle Structures Based on Animal Bone Properties

2013 ◽  
Vol 633 ◽  
pp. 3-14 ◽  
Author(s):  
Yan Rui ◽  
Aleksandar Subic ◽  
Monir Takla ◽  
Chun H. Wang ◽  
Anja Niehoff ◽  
...  
Keyword(s):  
Energy Absorption ◽  
Computer Aided Design ◽  
Bone Structure ◽  
Three Dimensional ◽  
Fe Method ◽  
Static Compression ◽  
Biomimetic Design ◽  
Conventional Vehicle ◽  
Bone Properties ◽  
Bone Structures

This paper presents a comprehensive biomimetic design approach to developing novel load bearing lightweight vehicle structures inspired by the structural properties of animal bones. Lightweight vehicle structures developed in this way would have increased stiffness at significantly reduced weight. In this research, trabecular (cancellous) bone was analyzed at the metaphyses of four different species including rat, rabbit, chicken, and sheep. Three-dimensional models of bone structures were reconstructed from micro-CT scanned images using the computer aided design software Mimics. Force resistance and energy absorption properties of relevant bone structures subjected to quasi-static compression loads were investigated and analysed using the Finite Element (FE) method. Based on the obtained results, the paper discusses the effects of load directions, bone structure allocation and model thickness on the energy absorption and force resistance of the bone structures. The simulation results obtained in this research were compared to the results of conventional vehicle side intrusion bars.

MECHANICAL ASPECTS OF A SINGLE-BUNDLE TIBIAL INTERFERENCE SCREW FIXATION IN A TENDON GRAFT ACL RECONSTRUCTION

2010 ◽  
Vol 22 (04) ◽  
pp. 271-278 ◽  
Author(s):  
Mahmoud Chizari ◽  
Bin Wang ◽  
Martyn Snow ◽  
Mel Barrett
Keyword(s):  
Soft Tissues ◽  
Bone Structure ◽  
Cruciate Ligament ◽  
Three Dimensional ◽  
Image Data ◽  
Qualitative Evaluation ◽  
Tendon Graft ◽  
Single Bundle ◽  
Element Analysis ◽  
Reconstructed Knee

Numerical methods applicable to the tibia bone and soft tissue biomechanics of an anterior cruciate ligament (ACL) reconstructed knee are presented in this paper. The aim is to achieve a better understanding of the mechanics of an ACL reconstructed knee. The paper describes the methodology applied in the development of an anatomically detailed three-dimensional ACL reconstructed knee model for finite element analysis from medical image data obtained from a computed tomography scan. Density segmentation techniques are used to geometrically define the knee bone structure and the encapsulated soft tissues configuration. Linear and nonlinear elastic constitutive material models are implemented to mechanically characterize the behavior of the biological materials. Preliminary numerical results for the model qualitative evaluation are presented.

Nonlinear Finite Element Analysis of Non-Structural Components Anchorage under Extreme Wind Loads

2019 ◽  
Author(s):  
Sálvio A. ALMEIDA Jr ◽  
Serhan Guner
Keyword(s):  
Finite Element ◽  
Elevated Temperatures ◽  
Concrete Slab ◽  
Three Dimensional ◽  
Nonlinear Finite Element ◽  
Scale Model ◽  
Structural Components ◽  
Element Analysis ◽  
Multi Scale ◽  
Service Load

<p>Steel anchors are widely used to fasten structures and non-structural components (NSC) to rooftop concrete slabs, especially in high-rise buildings. However, several NSC anchorage failures have been observed in the last decades upon the incidence of hurricanes, resulting in loss of service in essential buildings, detachment of the component, and water intrusion, all of which significantly delayed the recovery of the affected communities. From the observed failures, three main mechanisms were identified: steel rupture, concrete breakout, and bond failure. In this study, a three-dimensional nonlinear finite element methodology using a concrete damaged plasticity approach is developed to predict the response of steel anchors installed into a concrete slab. The methodology is verified with experimental results for each failure mechanism and subsequently used to study the effect of service-load concrete cracking and elevated temperatures – common conditions at rooftop level – on the response of the anchors. In addition, a first-of-its-kind multi-scale model of an NSC and its anchorage is created using the proposed methodology to investigate its behavior under dynamic hurricane load application. The findings suggest that these conditions can compromise the performance of NSC or promote its failure.</p>

scholarly journals Non-invasive implementation of nonlinear isogeometric analysis in an industrial FE software

2019 ◽  
Vol 37 (1) ◽  
pp. 237-261 ◽  
Author(s):  
Marie Tirvaudey ◽  
Robin Bouclier ◽  
Jean-Charles Passieux ◽  
Ludovic Chamoin
Keyword(s):  
Finite Element ◽  
Isogeometric Analysis ◽  
Three Dimensional ◽  
Nonlinear Problems ◽  
The Novel ◽  
Input Output ◽  
Element Analysis ◽  
Content Type ◽  
Lagrange Polynomials ◽  
Non Invasive

Purpose The purpose of this paper is to further simplify the use of NURBS in industrial environnements. Although isogeometric analysis (IGA) has been the object of intensive studies over the past decade, its massive deployment in industrial analysis still appears quite marginal. This is partly due to its implementation, which is not straightforward with respect to the elementary structure of finite element (FE) codes. This often discourages industrial engineers from adopting isogeometric capabilities in their well-established simulation environment. Design/methodology/approach Based on the concept of Bézier and Lagrange extractions, a novel method is proposed to implement IGA from an existing industrial FE code with the aim of bringing human implementation effort to the minimal possible level (only using standard input-output of finite element analysis (FEA) codes, avoid code-dependent subroutines implementation). An approximate global link to go from Lagrange polynomials to non-uniform-rational-B-splines functions is formulated, which enables the whole FE routines to be untouched during the implementation. Findings As a result, only the linear system resolution step is bypassed: the resolution is performed in an external script after projecting the FE system onto the reduced, more regular and isogeometric basis. The novel procedure is successfully validated through different numerical experiments involving linear and nonlinear isogeometric analyses using the standard input/output of the industrial FE software Code_Aster. Originality/value A non-invasive implementation of IGA into FEA software is proposed. The whole FE routines are untouched during the novel implementation procedure; a focus is made on the IGA solution of nonlinear problems from existing FEA software; technical details on the approach are provided by means of illustrative examples and step-by-step implementation; the methodology is evaluated on a range of two- and three-dimensional elasticity and elastoplasticity benchmarks solved using the commercial software Code_Aster.

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