scholarly journals Boundary element modeling and analysis of adhesive bonded structural joints

2007 ◽  
Vol 4 (1) ◽  
Author(s):  
G. Cavallini ◽  
G. Davi ◽  
A. Milazzo
Keyword(s):  
Boundary Element ◽  
Anisotropic Elasticity ◽  
Stress And Strain ◽  
Bonded Joints ◽  
Strain Fields ◽  
Modeling And Analysis ◽  
Structural Joints ◽  
Element Technique ◽  
Good Agreement

In this paper, a boundary element technique for modeling and analysis of adhesive bonded structural joints is presented. The formulation is developed in the framework of the anisotropic elasticity and attention is focused on the application to composite structural joints built with the splicing concept technique. To model and analyze composite bonded joints a multidomain implementation of the boundary element method has been used. It has been proven well suited and very effective for the characterization of the mechanical behavior of spliced joints, allowing the analysis of the high gradient stress and strain fields near the splice lines as well as the prediction of the overall distribution of the interlaminar tractions. Numerical results show good agreement with analytical solution and finite element analyses.

A Nonlinear Elastic Model for Isotropic Materials With Different Behavior in Tension and Compression

1982 ◽  
Vol 104 (1) ◽  
pp. 26-28 ◽  
Author(s):  
Gianluca Medri
Keyword(s):  
Mechanical Characterization ◽  
Three Dimensional ◽  
Small Deformation ◽  
Stress And Strain ◽  
Elastic Model ◽  
Strain Fields ◽  
Isotropic Materials ◽  
Tension And Compression ◽  
Nonlinear Elastic

This note presents a model suitable for the mechanical characterization of isotropic materials with different behavior in tension and compression. The model has been derived from the nonlinear elastic theory and elaborated to adapt it to the small deformation field; the constitutive relation may reliably correlate stress and strain fields even in three-dimensional elastic problems.

Mechanical Modeling and Characterization of the Curing Process of Underfill Materials

2002 ◽  
Vol 124 (2) ◽  
pp. 97-105 ◽  
Author(s):  
L. J. Ernst ◽  
C. van ’t Hof ◽  
D. G. Yang ◽  
M. S. Kiasat ◽  
G. Q. Zhang ◽  
...  
Keyword(s):  
Operating Conditions ◽  
Stress And Strain ◽  
Electronic Packages ◽  
Curing Process ◽  
Strain Fields ◽  
Starting Point ◽  
Polymer Curing ◽  
The Impact ◽  
Insight Into

Thermo-setting polymers are widely used as underfill materials to improve the reliability of electronic packages. In the design phase, the influence of underfill applications on reliability is often judged through thermal and mechanical simulations, under assumed operating conditions. Because of lacking insight into the mechanical processes due to polymer curing, the impact of processing induced residual stress fields is often neglected. To investigate the evolution of stress and strain fields during the curing process it is important to assume a more appropriate starting point for subsequent process modeling. Furthermore, study of possible damage originating from the fabrication process then comes within reach. To facilitate future analysis of stress and strain fields during the curing process a cure dependent constitutive relation is assumed. An approximate investigation method for the process-dependent mechanical properties, based on Dynamic Mechanic Analysis (DMA), is developed. As an illustration the parameter identification is performed for a selected epoxy resin.

Spectral FEM-Based Dynamic Characterization of Structural Joints: Theory and Experiment

2006 ◽  
Vol 326-328 ◽  
pp. 1629-1632
Author(s):  
Usik Lee ◽  
Joo Yong Cho ◽  
Chong Du Cho
Keyword(s):  
Experimental Work ◽  
Spectral Element ◽  
Dynamic Responses ◽  
Frequency Domain Method ◽  
Dynamic Characterization ◽  
Structural Joint ◽  
Structural Joints ◽  
Theory And Experiment ◽  
Good Agreement

A spectral element (SE)-model based frequency-domain method was proposed in the previous work [1] to identify the dynamic characteristics of a structural joint within onedimensional structures. In the present work, experimental work is conducted to verify the proposed method. The bolt-joint is represented by an equivalent joint model with four parameters, and the four parameters are determined by experimentally measured FRF data. The experimentally identified bolt-joint is shown to provide the dynamic responses which are in good agreement with measured dynamic responses.

Tumor Detection With a New Boundary Integral Equation Formulation

2004 ◽  
Author(s):  
F. Han ◽  
E. Pan ◽  
X. Jiang ◽  
Y. Qiao
Keyword(s):  
Elastic Moduli ◽  
Breast Tissue ◽  
Boundary Integral ◽  
Stress And Strain ◽  
Strain Fields ◽  
Tumor Mass ◽  
Integral Equation Formulation ◽  
Eshelby Inclusion ◽  
Inhomogeneity Problem

During pathological evolution, tissues mechanical properties, such as elastic moduli, will be changed. This feature has already been used in theory and application of elastography for detecting and characterizing tumors. In this paper, a tumor mass embedded in a breast tissue is modeled as an Eshelby inhomogeneity problem. Using a new anisotropic boundary element method (BEM) developed recently by the authors, the stress and strain fields due to an external load are solved efficiently and accurately. Furthermore, an inverse algorithm is also proposed for the detection and characterization of the embedded tumor mass. Numerical examples are presented to show that the BEM algorithm based on the Eshelby inclusion concept provides a useful method to solve certain biomedical problems.

Examples of nonlinear homogenization involving degenerate energies. I. Plane strain

2005 ◽  
Vol 461 (2063) ◽  
pp. 3681-3703 ◽  
Author(s):  
Isaac V Chenchiah ◽  
Kaushik Bhattacharya
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Plane Strain ◽  
Stress And Strain ◽  
Strain Fields ◽  
Perfectly Plastic ◽  
Plastic Materials ◽  
Nonlinear Homogenization

The study of polycrystals of shape-memory alloys and rigid-perfectly plastic materials gives rise to problems of nonlinear homogenization involving degenerate energies. This paper presents a characterization of the stress and strain fields in a class of problems in plane strain, and uses it to study examples including checkerboards and hexagonal microstructures. Consequences for shape-memory alloys and rigid-perfectly plastic materials are discussed.

Mathematical Model of the Effective Properties of a Fiber Reinforced Composite with a Linearly Graded Transition Zone

2010 ◽  
Vol 38 (4) ◽  
pp. 286-307
Author(s):  
Carey F. Childers
Keyword(s):  
Mathematical Model ◽  
Transition Zone ◽  
Effective Properties ◽  
Local Stress ◽  
Stress And Strain ◽  
Fiber Reinforced ◽  
Strain Fields ◽  
Shear Moduli ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite

Abstract Tires are fabricated using single ply fiber reinforced composite materials, which consist of a set of aligned stiff fibers of steel material embedded in a softer matrix of rubber material. The main goal is to develop a mathematical model to determine the local stress and strain fields for this isotropic fiber and matrix separated by a linearly graded transition zone. This model will then yield expressions for the internal stress and strain fields surrounding a single fiber. The fields will be obtained when radial, axial, and shear loads are applied. The composite is then homogenized to determine its effective mechanical properties—elastic moduli, Poisson ratios, and shear moduli. The model allows for analysis of how composites interact in order to design composites which gain full advantage of their properties.

scholarly journals Characterization of Tiled Architecture for C-Band 1-Bit Beam-Steering Transmitarray

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1259
Author(s):  
Dmitry Kozlov ◽  
Irina Munina ◽  
Pavel Turalchuk ◽  
Vitalii Kirillov ◽  
Alexey Shitvov ◽  
...  
Keyword(s):  
Communication Systems ◽  
Beam Steering ◽  
Unit Cell ◽  
Electromagnetic Simulations ◽  
Fifth Generation ◽  
Full Wave ◽  
Array Architecture ◽  
Modulation Pattern ◽  
Good Agreement

A new implementation of a beam-steering transmitarray is proposed based on the tiled array architecture. Each pixel of the transmitarray is manufactured as a standalone unit which can be hard-wired for specific transmission characteristics. A set of complementary units, providing reciprocal phase-shifts, can be assembled in a prescribed spatial phase-modulation pattern to perform beam steering and beam forming in a broad spatial range. A compact circuit model of the tiled unit cell is proposed and characterized with full-wave electromagnetic simulations. Waveguide measurements of a prototype unit cell have been carried out. A design example of a tiled 10 × 10-element 1-bit beam-steering transmitarray is presented and its performance benchmarked against the conventional single-panel, i.e., unibody, counterpart. Prototypes of the tiled and single-panel C-band transmitarrays have been fabricated and tested, demonstrating their close performance, good agreement with simulations and a weak effect of fabrication tolerances. The proposed transmitarray antenna configuration has great potential for fifth-generation (5G) communication systems.

scholarly journals Visco-Hyperelastic Characterization of the Equine Immature Zona Pellucida

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1223
Author(s):  
Elisa Ficarella ◽  
Mohammad Minooei ◽  
Lorenzo Santoro ◽  
Elisabetta Toma ◽  
Bartolomeo Trentadue ◽  
...  
Keyword(s):  
Zona Pellucida ◽  
Soft Matter ◽  
Mechanical Response ◽  
Mechanical Characterization ◽  
Nonlinear Material ◽  
Prony Series ◽  
Critical Comparison ◽  
Highly Nonlinear ◽  
Good Agreement

This article presents a very detailed study on the mechanical characterization of a highly nonlinear material, the immature equine zona pellucida (ZP) membrane. The ZP is modeled as a visco-hyperelastic soft matter. The Arruda–Boyce constitutive equation and the two-term Prony series are identified as the most suitable models for describing the hyperelastic and viscous components, respectively, of the ZP’s mechanical response. Material properties are identified via inverse analysis based on nonlinear optimization which fits nanoindentation curves recorded at different rates. The suitability of the proposed approach is fully demonstrated by the very good agreement between AFM data and numerically reconstructed force–indentation curves. A critical comparison of mechanical behavior of two immature ZP membranes (i.e., equine and porcine ZPs) is also carried out considering the information on the structure of these materials available from electron microscopy investigations documented in the literature.

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