scholarly journals Simulation of cellular structures with a coupled FEM-FCM approach based on CT data

2021 ◽  
Vol 16 (1) ◽  
pp. 57-70
Author(s):  
Ulrich Gabbert ◽  
Mathias Würkner
Keyword(s):  
Strain Analysis ◽  
Theoretical Background ◽  
General Idea ◽  
Benchmark Problems ◽  
The Finite Element Method ◽  
Cellular Microstructure ◽  
Fatigue And Fracture ◽  
Ct Data ◽  
Specific Implementation ◽  
Finite Cell

The application of cellular structural materials provide new light-weight capabilities in many engineering fields. But the microstructure significantly influences the strength, the fatigue and fracture behavior as well as the life span of a structure made from cellular materials. The current paper illustrates the general idea how to take into account the cellular microstructure in the stress and strain analysis. The detailed geometry, including all discontinuities in the microstructure is available, for instance from measurements provided by the computed tomography (CT). The proposed simulation methodology is a combination of the finite element method (FEM) and the finite cell method (FCM). The FCM approach is applied in regions where discontinuities occur, avoiding a body-fitted mesh. As basis of the FEM-FCM coupling the commercial FEA package Abaqus is used. The theoretical background and the overall simulation workflow along with specific implementation details are discussed. Finally, academic benchmark problems are used to verify the developed coupling method.

scholarly journals DEVELOPMENT PROSPECTS OF 3D MODELLING IN FORENSIC MEDICINE: BIM-TECHNOLOGY AND 4D MODELLING

2020 ◽  
Vol 6 (1) ◽  
pp. 4-13
Author(s):  
S. V. Leonov ◽  
Yu. P. Shakiryanova ◽  
P. V. Pinchuk
Keyword(s):  
Forensic Medicine ◽  
3D Model ◽  
Three Dimensional ◽  
3D Modelling ◽  
Line Of Sight ◽  
The Finite Element Method ◽  
Practical Application ◽  
Cad Modelling ◽  
Ct Data ◽  
Development Prospects

The present article provides an overview of the main methods of three-dimensional modelling currently used in various fields of science and practice, including forensic medicine. The possibilities of used methods are described.The authors introduce the concept of BIM-technology, which allows various methods working in 3D to be applied comprehensively: from photogrammetry and computed tomography to line-of-sight and CAD modelling. The article presents a case involving practical application of BIM-technology within the practical work of a forensic expert. The possibilities of supplementing and expanding the model over time within a single information field (4D modelling) are shown.Using the example of a specific examination, it is shown for which studies the created BIM-model can be employed, as well as what issues can be solved with its help. To that end, CT data was studied with the subsequent reconstruction of the 3D model of the damaged skull; blood traces were analysed with the subsequent 3D modelling of circumstances at the scene. The following methods were used for the reconstruction: photogrammetry, the finite element method and line-of-sight modelling of gunshot trajectories.Applied within a situational forensic medical examination, BIM-technologies successfully provided answers to the investigator’s questions: mechanism underlying the formation of blood traces; location of the bleeding source; trajectories of projectiles and their elements; circumstances of the occurrence; position of the shooter; prediction of glass breakage caused by a bullet.Conclusion. New computer technologies (BIM-technology and 4D modelling) constitute the next step in the development of three-dimensional modelling. Their introduction into the practice of experts will help create a single information field for all objects under study, as well as consider all possible investigative leads as objectively as possible

3D finite element-based modeling of discontinuities

2020 ◽  
pp. 35-39
Author(s):  
I. E. Semenova ◽  
◽  
S. V. Dmitriev ◽  
A. A. Shestov ◽  
◽  
...  
Keyword(s):  
Finite Element ◽  
Rock Mass ◽  
Strain Analysis ◽  
Interface Element ◽  
The Finite Element Method ◽  
Stress Strain ◽  
Interface Elements ◽  
Strain Behavior ◽  
Improve Reliability ◽  
Optimal Type

A rock mass is composed of blocks, and the interfaces of various scale blocks represent different kind discontinuities. Such structure is also associated with nonuniformity of stresses. The stress–strain behavior of rock mass in the Khibiny apatite–nepheline massif in the course of mining is governed by natural geological and induced faulting. This study considers modification of the finite element method in the stress–strain analysis of rocks with regard to deformation at interfaces of different-modulus media. After 2D tests of interface elements, an optimal type of the interface element was selected for the 3D modification implementation. The latter can improve reliability of geomechanical forecasts in mineral mining in complicated geological and geodynamic conditions. From the test data on modification of interface elements, the optimal interface element is assumed to be the six-node interface element proposed by V. Kalyakin and Jianchao Li. The six-node interface element is introduced in the model of a tunnel with simulation of an unloading line at the boundary. The adequate results on adjacent rock deformation are obtained. The 3D interface element modification reveals its peculiarities and limitations as regards introduction in finite element models of mineral deposits and enclosing rock mass. The ways of solving these problems are proposed.

scholarly journals Models of stents – Comparison and applications

2007 ◽  
pp. S115-S121
Author(s):  
J Záhora ◽  
A Bezrouk ◽  
J Hanuš
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Analytical Model ◽  
Model Evaluation ◽  
Structural Mechanics ◽  
Theoretical Background ◽  
Measurement Equipment ◽  
The Finite Element Method ◽  
Basic Properties ◽  
New Models

The aim of this study was to analyze the possibilities of various types of stent modeling and to develop some new models. A brief survey of basic properties of stents and a list of basic designs of stents is presented. Two approaches to stent modeling were identified. Structural mechanics is the theoretical background of our analytical model of a spiral stent. The finite element method was also used. The measurement equipment for model evaluation was developed.

In situdiffraction strain analysis of elastically deformed polycrystalline thin films, and micromechanical interpretation

2009 ◽  
Vol 42 (6) ◽  
pp. 1073-1084 ◽  
Author(s):  
D. Faurie ◽  
O. Castelnau ◽  
R. Brenner ◽  
P.-O. Renault ◽  
E. Le Bourhis ◽  
...  
Keyword(s):  
Thin Films ◽  
Crystallographic Texture ◽  
Elastic Anisotropy ◽  
Large Strain ◽  
Strain Analysis ◽  
Tensile Tests ◽  
Theoretical Background ◽  
Polycrystalline Thin Films ◽  
Au Thin Films ◽  
Supported Gold

In situtensile tests have been carried out under synchrotron radiation on supported gold (Au) thin films exhibiting a pronounced crystallographic texture. The 2θ shift of X-ray diffraction lines has been recorded for different specimen orientations and several loading levels in the elastic domain. The data obtained demonstrate the large strain heterogeneities generated within the specimen because of the intergranular interactions associated with the large elastic anisotropy of Au grains. To interpret these results, the use of a multi-scale micromechanical approach is unavoidable. The theoretical background of such methods is described, and the points where exact results can be obtained and where approximations have to be introduced are highlighted. It is shown that the Vook–Witt model, for which a general formulation is provided, is the exact solution for polycrystals exhibiting a laminate microstructure, which is a significant departure from the standard thin-film microstructures. Among several standard models used in the field, the self-consistent model is the only one that reproduces the experimental data correctly. This is achieved by accounting for the actual crystallographic texture of the specimen, and assuming pancake-shaped two-point statistics for the morphological texture. A discussion of the limitations of this approach, originally developed for bulk materials, is given for the specific case of thin films.

scholarly journals Nonlinear stress-strain analysis of terrain using the finite element method

2012 ◽  
pp. 301-320
Author(s):  
Slobodan Coric ◽  
Laslo Caki ◽  
Dragoslav Rakic ◽  
Stanko Coric
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Strain Analysis ◽  
The Finite Element Method ◽  
Stress Strain ◽  
Nonlinear Stress ◽  
Element Method

scholarly journals Experimental design and biometric research. Toward innovations

2021 ◽  
Keyword(s):  
Electrodermal Activity ◽  
Theoretical Background ◽  
T Test ◽  
Wilcoxon Test ◽  
General Idea ◽  
Research Report ◽  
Standard Procedures ◽  
Dependent Sample ◽  
Guided Tours ◽  
Dependent Samples

This e-book aims to present the most critical aspects of knowledge about using experiments in economics and practical tools for using them. The topic is extended to the more advanced and increasing in popularity area of biometric research. The book is divided into three parts mirroring experimentation. The first part provides theoretical background and tips about organising own research. The chapter is concluded with a guide focused on writing a research report in APA style. This part includes an example of the actual research report. The next part has two chapters, and both are guided tours allowing to plan and conduct eye-tracking research and electrodermal activity research (EDA). The chapters contain details about preparing experiments, conducting them, using the dedicated software to analyse collected data and interpreting the default charts. The last part is devoted to the data analysis and is universal, goes beyond the biometric experiments. There are three chapters in this part covering the standard procedures used in the analysis of experiments. The first part includes tests for one hypothesis: parametric t-test and One-Way ANOVA and non-parametric siblings: Mann Whitney U test and Kruskal-Wallis test. The next part describes tests allowing testing more hypotheses: ANOVA without repetition and ANOVA with repetitions. Furthermore, the last chapter deals with dependent samples, which are a popular approach in experiments. This part describes the dependent sample t-test and Wilcoxon test. The effect sizes calculations are included; each test is shown with screenshots from SPSS and some additional screenshots from Excel. This approach allows following the procedure step by step. The examples help easily understand procedures and interpretations; they were chosen from areas of sustainability and innovations to match the general idea of the e-books series prepared within the CENETSIE program. The book contains texts that can be useful in the teaching process. It can be helpful in graduate programs in economics and business schools. Programs of doctoral schools cab benefit from this book as well.

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