Multi-mode modeling of global and local deformation, and failure, in particle filled epoxy systems

2016 ◽  
Vol 88 ◽  
pp. 1-9 ◽  
Author(s):  
Sam Krop ◽  
Han E.H. Meijer ◽  
Lambert C.A. van Breemen
Keyword(s):  
Local Deformation ◽  
Deformation And Failure ◽  
Global And Local ◽  
Multi Mode ◽  
Epoxy Systems

scholarly journals Influencing factors of global and local deformation in hot compression

2018 ◽  
Vol 15 ◽  
pp. 381-387
Author(s):  
Baohui Tian ◽  
Siegfried Kleber ◽  
Silvia Schneller ◽  
Peter Markiewicz
Keyword(s):  
Influencing Factors ◽  
Local Deformation ◽  
Hot Compression ◽  
Global And Local

Non-Rigid Liver Registration in Liver Computed Tomography Images Using Elastic Method with Global and Local Deformations

2021 ◽  
Vol 11 (3) ◽  
pp. 810-816
Author(s):  
Taeyong Park ◽  
Jeongjin Lee ◽  
Juneseuk Shin ◽  
Kyoung Won Kim ◽  
Ho Chul Kang
Keyword(s):  
Computed Tomography ◽  
Liver Cancer ◽  
Ct Images ◽  
Local Deformation ◽  
Rigid Registration ◽  
Liver Ct ◽  
Liver Surface ◽  
Global And Local ◽  
Local Deformations

The study of follow-up liver computed tomography (CT) images is required for the early diagnosis and treatment evaluation of liver cancer. Although this requirement has been manually performed by doctors, the demands on computer-aided diagnosis are dramatically growing according to the increased amount of medical image data by the recent development of CT. However, conventional image segmentation, registration, and skeletonization methods cannot be directly applied to clinical data due to the characteristics of liver CT images varying largely by patients and contrast agents. In this paper, we propose non-rigid liver segmentation using elastic method with global and local deformation for follow-up liver CT images. To manage intensity differences between two scans, we extract the liver vessel and parenchyma in each scan. And our method binarizes the segmented liver parenchyma and vessel, and performs the registration to minimize the intensity difference between these binarized images of follow-up CT images. The global movements between follow-up CT images are corrected by rigid registration based on liver surface. The local deformations between follow-up CT images are modeled by non-rigid registration, which aligns images using non-rigid transformation, based on locally deformable model. Our method can model the global and local deformation between follow-up liver CT scans by considering the deformation of both the liver surface and vessel. In experimental results using twenty clinical datasets, our method matches the liver effectively between follow-up portal phase CT images, enabling the accurate assessment of the volume change of the liver cancer. The proposed registration method can be applied to the follow-up study of various organ diseases, including cardiovascular diseases and lung cancer.

Global and local deformation behavior and mechanical properties of individual phases in a quenched and partitioned steel

2015 ◽  
Vol 630 ◽  
pp. 27-35 ◽  
Author(s):  
I. de Diego-Calderón ◽  
D. De Knijf ◽  
M.A. Monclús ◽  
J.M. Molina-Aldareguia ◽  
I. Sabirov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Deformation Behavior ◽  
Local Deformation ◽  
Global And Local

The Deformation and Failure Mechanism of the Excavation Damage Soil Slope under the Action of Seismic Load

2011 ◽  
Vol 382 ◽  
pp. 444-449
Author(s):  
A. Fayou ◽  
Ji Ming Kong ◽  
Zhen Qiang Ni
Keyword(s):  
Wenchuan Earthquake ◽  
Local Deformation ◽  
Slope Deformation ◽  
Seismic Load ◽  
Soil Slope ◽  
The Finite Element Method ◽  
Deformation And Failure ◽  
Mountain Hazards ◽  
Excavation Damage

Wenchuan earthquak induced a large number of mountain hazards. Through the survey found that manual excavation slopes tend to become concentrated area of mountain disaster, it’s indicate that the effect of excavation damage on the slope deformation and failure under seismic load is very obvious. Soil slope deformation as one types of mountain hazards induced by Wenchuan earthquake, and it’s also seriously affected by excavation damage. In this paper, as Shui Caoping landslide for example, using the finite element method to simulate the landslide and analysis the overall stability and the local deformation and failure of slope affected by the excavation damage. Analysis shows that the local damage is significantly induced by excavation, and resulting in vertical stress and plastic strain increased in the local of slope near the excavation face. While excavating also has the role of unloading. The results basic agreement with the characteristics of the slope deformation and failure induced by Wenchuan earthquake.

scholarly journals Understanding the deformation gradient in Abaqus and key guidelines for anisotropic hyperelastic user material subroutines (UMATs)

2019 ◽  
Author(s):  
David Nolan ◽  
Caitriona Lally ◽  
Patrick McGarry
Keyword(s):  
Local Coordinate System ◽  
Deformation Gradient ◽  
Worked Examples ◽  
Local Deformation ◽  
Cauchy Stress ◽  
Precise Understanding ◽  
Key Issues ◽  
Key Steps ◽  
Orientation Systems ◽  
Global And Local

This tutorial paper provides a step-by-step guide to developing a comprehensive understanding of the different forms of the deformation gradient used in Abaqus, and outlines a number of key issues that must be considered when developing an Abaqus user defined material subroutine (UMAT) in which the Cauchy stress is computed from the deformation gradient. Firstly, we examine the "classical" forms of global and local deformation gradients. We then show that Abaqus/Standard does not use the classical form of the local deformation gradient when continuum elements are used, and we highlight the important implications for UMAT development. We outline the key steps that must be implemented in developing an anisotropic fibre-reinforced hyperelastic UMAT for use with continuum elements and local orientation systems. We also demonstrate that a classical local deformation gradient is provided by Abaqus/Standard if structural (shell and membrane) elements are used, and by Abaqus/Explicit for all element types. We emphasise, however, that the majority of biomechanical simulations rely on the use of continuum elements with a local coordinate system in Abaqus/Standard, and therefore the development of a hyperelastic UMAT requires an in-depth and precise understanding of the form of the non-classical deformation gradient provided as input by Abaqus. Several worked examples and case studies are provided for each section, so that the details and implications of the form of the deformation gradient can be fully understood. For each worked example in this tutorial paper the source files and code (Abaqus input files, UMATs, and Matlab script files) are provided, allowing the reader to efficiently explore the implications of the form of the deformation gradient in the development of a UMAT.

REORIENTATION OF FIBRES AND LOCAL MECHANISMS OF DEFORMATION IN A WOOD-INSPIRED COMPOSITE

2012 ◽  
Vol 04 (01) ◽  
pp. 1250003
Author(s):  
E. I. SAAVEDRA FLORES ◽  
M. S. MURUGAN ◽  
M. I. FRISWELL ◽  
E. A. DE SOUZA NETO
Keyword(s):  
Mechanical Response ◽  
Local Deformation ◽  
Simple Expression ◽  
Deformation And Failure ◽  
Multi Scale ◽  
Wide Range ◽  
Present Composite ◽  
Computational Homogenisation ◽  
Mechanisms Of Deformation ◽  
Good Agreement

This paper investigates the reorientation of fibres and local mechanisms of deformation in a composite material inspired by the mechanics and structure of wood cell-walls. The mechanical response of the material is calculated under tensile loading conditions by means of the computational homogenisation of a two-dimensional representative volume element (RVE) of material. Here, the fibres are represented by a periodic alternation of alumina and magnesium alloy fractions, embedded in a soft epoxy matrix. In order to validate the present multi-scale framework, we compare our numerical prediction for the reorientation of fibres in the wood cell-wall composite with experimental data, finding a good agreement for a wide range of strains. Numerical simulations show that the model is able to describe the reorientation of fibres and the different stages of local deformation and failure in the proposed wood-inspired material. Furthermore, we assess a simple expression to calculate the reorientation of fibres and the in-plane Poisson's ratio of the present composite.

Numerical Investigation of Tearing Fracture of Wrinkled Pipe

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Arman U. Ahmed ◽  
Sreekanta Das ◽  
J. J. Roger Cheng
Keyword(s):  
Local Buckling ◽  
Element Model ◽  
Local Deformation ◽  
Slope Instability ◽  
Pipe Material ◽  
Large Displacements ◽  
Key Factor ◽  
Detailed Assessment ◽  
Deformation Patterns ◽  
Global And Local

Steel pipelines, buried in cold regions, often respond to thermal strains and/or geotechnical movement caused by factors such as thaw settlement, frost heave, and slope instability. These complex field conditions can impose large displacements on these pipelines, resulting in localized wrinkles well into the plastic range of the pipe material. Eventually, there is a possibility of a fracture occurring at a wrinkled location under continuous deformation. A recent field fracture and a failed laboratory specimen have been observed within a telescopic wrinkle under tearing action and the loading histories have been found to be monotonic, without significant strain reversals. These incidents underscore the need for a detailed investigation, which seeks to answer fundamental questions regarding this unique mode of failure. In this study, a finite element model has been developed, which is capable of accounting for material nonlinearity effects, large displacements, large rotations, initial imperfections, and possible complex contact surfaces. Based on limited test data, the comparison of the numerical and the experimental results demonstrates the ability of the present model to predict the local buckling behavior of pipes when deformed well into the postwrinkling range. The results of this analytical work include the global and local deformation patterns and a detailed assessment of the stress-strain relations at the region of the telescopic wrinkle. The results obtained from this study have recognized the occurrence of strain reversal at the sharp fold of the wrinkle on the compression side of the pipe, a phenomenon that could be considered to be the key factor for triggering this unique failure mechanism.

Three-dimensional systolic kinematics of the right ventricle

2005 ◽  
Vol 289 (5) ◽  
pp. H1826-H1833 ◽  
Author(s):  
Idith Haber ◽  
Dimitris N. Metaxas ◽  
Tal Geva ◽  
Leon Axel
Keyword(s):  
Right Ventricle ◽  
Three Dimensional ◽  
Normal Subjects ◽  
Local Deformation ◽  
Thin Wall ◽  
Image Processing Techniques ◽  
Strain Pattern ◽  
The Right ◽  
Processing Techniques ◽  
Global And Local

The right ventricle (RV) of the heart is responsible for pumping blood to the lungs. Its kinematics are not as well understood as that of the left ventricle (LV) due to its thin wall and asymmetric geometry. In this study, the combination of tagged MRI and three-dimensional (3-D) image-processing techniques was used to reconstruct 3-D RV-LV motion and deformation. The reconstructed models were used to quantify the 3-D global and local deformation of the ventricles in a set of normal subjects. When compared with the LV, the RV exhibited a similar twisting pattern, a more longitudinal strain pattern, and a greater amount of displacement.

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