An Interface Model for the Periodontal Ligament

2002 ◽  
Vol 124 (5) ◽  
pp. 538-546 ◽  
Author(s):  
Massimiliano Gei ◽  
Francesco Genna ◽  
Davide Bigoni
Keyword(s):  
Simple Model ◽  
Finite Elements ◽  
Mechanical Behavior ◽  
Periodontal Ligament ◽  
Three Dimensional ◽  
Experimental Results ◽  
Constitutive Law ◽  
Numerical Calculations ◽  
Interface Model ◽  
Nonlinear Interface

A nonlinear interface constitutive law is formulated for modeling the mechanical behavior of the periodontal ligament. This gives an accurate interpolation of the few available experimental results and provides a reasonably simple model for mechanical applications. The model is analyzed from the viewpoints of both mathematical consistency and effectiveness in numerical calculations. In order to demonstrate the latter, suitable two- and three-dimensional nonlinear interface finite elements have been implemented.

Three-Dimensional Solutions for Rotor Blades Using High-Order Geometrical Nonlinear Beam Finite Elements

2019 ◽  
Vol 64 (3) ◽  
pp. 1-10
Author(s):  
Matteo Filippi ◽  
Alfonso Pagani ◽  
Erasmo Carrera
Keyword(s):  
Finite Elements ◽  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Shear Deformation Theory ◽  
High Order ◽  
Rotor Blades ◽  
Constitutive Law ◽  
Displacement Fields ◽  
Cross Sectional ◽  
The Cross

This paper proposes a geometrically nonlinear three-dimensional formalism for the static and dynamic study of rotor blades. The structures are modeled using high-order beam finite elements whose kinematics are input parameters of the analysis. The displacement fields are written using two-dimensional Taylor- and Lagrange-like expansions of the cross-sectional coordinates. As far as the Taylor-like polynomials are concerned, the linear case is similar to the first-order shear deformation theory, whereas the higher-order expansions include additional contributions that describe the warping of the cross section. The Lagrange-type kinematics instead utilizes the displacements of certain physical points as degrees of freedom. The inherent three-dimensional nature of the Carrera unified formulation enables one to include all Green–Lagrange strain components as well as all coupling effects due to the geometrical features and the three-dimensional constitutive law. A number of test cases are considered to compare the current solutions with experimental and theoretical results reported in terms of large deflections/rotations and frequencies related to small amplitude vibrations.

A Stochastic Nonlinear Constitutive Law for Concrete

1989 ◽  
Vol 111 (4) ◽  
pp. 443-449 ◽  
Author(s):  
A. Fafitis ◽  
Y. H. Won
Keyword(s):  
Stochastic Model ◽  
Elastic Moduli ◽  
Three Dimensional ◽  
Path Dependency ◽  
Experimental Results ◽  
Constitutive Law ◽  
Induced Anisotropy ◽  
Nonproportional Loading ◽  
Strain Relationship ◽  
Good Agreement

An incremental three-dimensional stress-strain relationship for concrete with induced anisotropy has been developed. The nonlinearity and path-dependency are modeled by expressing the elastic moduli at each increment as function of the octahedral and deviatoric strains, based on a uniaxial stochastic model developed earlier. Predictions of multiaxial response under proportional and nonproportional loading are in good agreement with experimental results.

Viscoplastic Analysis of Adhesive Joints

1996 ◽  
Vol 63 (1) ◽  
pp. 21-26 ◽  
Author(s):  
G. K. Hu ◽  
F. Schmit ◽  
D. Baptiste ◽  
D. Franc¸ois
Keyword(s):  
Hydrostatic Stress ◽  
Three Dimensional ◽  
Constant Strain Rate ◽  
Adhesive Layer ◽  
Butt Joint ◽  
Lap Joints ◽  
Experimental Results ◽  
Constitutive Law ◽  
Tensile Creep ◽  
Account Due

The uniaxial constitutive law for an adhesive is studied by constant strain rate tensile, creep and relaxation tests. The S-D effect of the adhesive is taken into account by using the Raghava yielding criterion in a three dimensional constitutive formulation. The obtained constitutive law is then used to analyze a single lap joint and a butt joint by a finite element method. Constant cross head speed tensile and creep loading cases are examined. For a butt joint, the results show that the viscous effect and the influence of the hydrostatic stress must be taken into account due to the variation of the hydrostatic stress and of the loading rate in the adhesive layer as function of its thickness. A comparison with experimental results is also given. A good agreement between viscoplastic calculations and experimental results is obtained for single-lap joints. A reasonable result is obtained for butt joints and the discrepancy is attributed to interfacial debonding.

Geometric Model and Elastic Constant Prediction of 3D Four-Step Braided Composites Based on the Cubic Spline Curve

2016 ◽  
Vol 08 (02) ◽  
pp. 1650019 ◽  
Author(s):  
Chenbing Ni ◽  
Gaofeng Wei
Keyword(s):  
Geometric Model ◽  
Three Dimensional ◽  
Cubic Spline ◽  
Numerical Results ◽  
Unit Cell ◽  
Experimental Results ◽  
Numerical Calculations ◽  
Braided Composites ◽  
Spline Curve ◽  
Cubic Spline Curve

In this paper, the three-dimensional (3D) four-step ([Formula: see text]) rectangular braided composites are analyzed, the internal yarn spatial topology and mechanical model are determined, a new geometric model, which uses a cubic spline curve to fit yarn trajectory, is presented. The new geometric model can be divided into three types of unit cell models which are the interior, surface and corner unit cell. Based on the new proposed geometric model and the stiffness averaging theory, the corresponding elastic constants are predicted. The predicted numerical results are calculated, and compared with the experimental results. Numerical examples indicate that the numerical calculations well agree with the experimental results. Error values between numerical calculations and experimental results are less than 7.5%. The numerical results verify the validity and accuracy of the new geometrical model.

Numerical Calculations of Wing Tip Vortices and Effects of Suction at Wing Tip

2002 ◽  
Author(s):  
S. Okada ◽  
N. Arai ◽  
K. Hiraoka
Keyword(s):  
Three Dimensional ◽  
Turbulence Models ◽  
Experimental Results ◽  
Numerical Calculations ◽  
Analysis Software ◽  
Tip Vortices ◽  
Fluid Analysis ◽  
Induced Drag ◽  
Wing Tip ◽  
Good Agreement

In three-dimensional wing, the induced drag occurs by wing tip vortices. So it is important to study the characteristics of wing tip vortices in order to reduce the induced drag. In this paper, at first comparing the numerically calculated results of three-dimensional incompressible flow using several turbulence models and the law speed wind tunnel experimental results using a two-dimensional hot wire anemometer, the characteristics of wing tip vortices are studied. In the numerical calculations, the multipurpose fluid analysis software FLUENT and the pre-processor GAMBIT are used on popular PC. The numerical results that were obtained by using the RNG k-ε turbulence model is good agreement with the experimental results. Then controlling the flow near the wing tip by suction, the effects against wing tip vortices are studied by numerically and experimentally. It is shown by numerical calculation and experiment that the strength of wing tip vortices decrease by appropriate suction at the wing tip.

The Bending Interface Model for Flexible Three-Dimensional Microstructure

2011 ◽  
Vol 58-60 ◽  
pp. 1082-1087
Author(s):  
Yi Yong Yao ◽  
Li Ping Zhao
Keyword(s):  
Composite Materials ◽  
Mechanical Behavior ◽  
Single Cell ◽  
Mechanical Model ◽  
Three Dimensional ◽  
Interfacial Properties ◽  
Interface Stress ◽  
Interface Model ◽  
Bending Properties ◽  
Cell Method

For the flexible three-dimensional microstructure, the GMC single-cell method was applied to establish the mechanical model of the bending interface, and then the interface micro-element method based on composite materials was performed to work on the interfacial properties of weak interfaces and micro-mechanical behavior. As a result, a flexible interface model for the interface stress was constructed and it would be helpful to improve the bending properties of the flexible three-dimensional microstructure.

scholarly journals Lath Martensite Microstructure Modeling: A High-Resolution Crystal Plasticity Simulation Study

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 691
Author(s):  
Francisco-José Gallardo-Basile ◽  
Yannick Naunheim ◽  
Franz Roters ◽  
Martin Diehl
Keyword(s):  
High Resolution ◽  
Mechanical Behavior ◽  
Crystal Plasticity ◽  
Lath Martensite ◽  
Three Dimensional ◽  
Building Blocks ◽  
Quantitative Agreement ◽  
Carbon Steels ◽  
Plastic Behavior ◽  
Austenitic Phase

Lath martensite is a complex hierarchical compound structure that forms during rapid cooling of carbon steels from the austenitic phase. At the smallest, i.e., ‘single crystal’ scale, individual, elongated domains, form the elemental microstructural building blocks: the name-giving laths. Several laths of nearly identical crystallographic orientation are grouped together to blocks, in which–depending on the exact material characteristics–clearly distinguishable subblocks might be observed. Several blocks with the same habit plane together form a packet of which typically three to four together finally make up the former parent austenitic grain. Here, a fully parametrized approach is presented which converts an austenitic polycrystal representation into martensitic microstructures incorporating all these details. Two-dimensional (2D) and three-dimensional (3D) Representative Volume Elements (RVEs) are generated based on prior austenite microstructure reconstructed from a 2D experimental martensitic microstructure. The RVEs are used for high-resolution crystal plasticity simulations with a fast spectral method-based solver and a phenomenological constitutive description. The comparison of the results obtained from the 2D experimental microstructure and the 2D RVEs reveals a high quantitative agreement. The stress and strain distributions and their characteristics change significantly if 3D microstructures are used. Further simulations are conducted to systematically investigate the influence of microstructural parameters, such as lath aspect ratio, lath volume, subblock thickness, orientation scatter, and prior austenitic grain shape on the global and local mechanical behavior. These microstructural features happen to change the local mechanical behavior, whereas the average stress–strain response is not significantly altered. Correlations between the microstructure and the plastic behavior are established.

Influence of the Welded Joint on the Mechanical Behavior of Steel Piles during Static and Dynamic Deformation

2007 ◽  
Vol 345-346 ◽  
pp. 1469-1472
Author(s):  
Gab Chul Jang ◽  
Kyong Ho Chang ◽  
Chin Hyung Lee
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Mechanical Behavior ◽  
Welded Joint ◽  
Dynamic Deformation ◽  
Three Dimensional ◽  
Steel Structures ◽  
Residual Stress Distribution ◽  
Dynamic Mechanical Behavior ◽  
Steel Piles

During manufacturing the welded joint of steel structures, residual stress is produced and weld metal is used inevitably. And residual stress and weld metal influence on the static and dynamic mechanical behavior of steel structures. Therefore, to predict the mechanical behavior of steel pile with a welded joint during static and dynamic deformation, the research on the influence of the welded joints on the static and dynamic behavior of steel pile is clarified. In this paper, the residual stress distribution in a welded joint of steel piles was investigated by using three-dimensional welding analysis. The static and dynamic mechanical behavior of steel piles with a welded joint is investigated by three-dimensional elastic-plastic finite element analysis using a proposed dynamic hysteresis model. Numerical analyses of the steel pile with a welded joint were compared to that without a welded joint with respect to load carrying capacity and residual stress distribution. The influence of the welded joint on the mechanical behavior of steel piles during static and dynamic deformation was clarified by comparing analytical results

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