scholarly journals Plastic Deformation of a Perforated Sheet With Nonuniform Circular Holes Along the Thickness Direction

2002 ◽  
Vol 124 (4) ◽  
pp. 434-439
Author(s):  
Fuh-Kuo Chen ◽  
Yi-Che Lee
Keyword(s):  
Plastic Deformation ◽  
Yield Criterion ◽  
Plastic Behavior ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Circular Holes ◽  
Perforated Sheet ◽  
Uniform Diameter ◽  
The Given ◽  
Equivalent Continuum

For a perforated sheet with circular holes, used in shadow masks, the diameter of the circular hole varies through the thickness, and the nonuniform circular holes are arranged in a triangular pattern. In order to simplify the analysis, a perforated sheet with equivalent circular holes of uniform diameter is proposed such that its plastic behavior is similar to that with the given nonuniform circular holes. In this study, a yield criterion is discussed for the perforated sheet with uniform circular holes by employing an equivalent continuum approach, which is then applied to examine the plastic deformation of the perforated sheet with nonuniform circular holes. The analytical results predicted by the theory, including those for the apparent yield stresses and strain ratios, are verified by the results obtained from the finite element analysis and also from experiments.

scholarly journals Plastic Deformation of a Perforated Sheet With Non-Uniform Circular Holes Along the Thickness Direction

2002 ◽  
Vol 125 (1) ◽  
pp. 75-80 ◽  
Author(s):  
Fuh-Kuo Chen ◽  
Yi-Che Lee
Keyword(s):  
Plastic Deformation ◽  
Yield Criterion ◽  
Plastic Behavior ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Circular Holes ◽  
Perforated Sheet ◽  
Uniform Diameter ◽  
The Given ◽  
Equivalent Continuum

For a perforated sheet with circular holes, used in shadow masks, the diameter of the circular hole varies through the thickness, and the non-uniform circular holes are arranged in a triangular pattern. In order to simplify the analysis, a perforated sheet with equivalent circular holes of uniform diameter is proposed such that its plastic behavior is similar to that with the given non-uniform circular holes. In this study, a yield criterion is discussed for the perforated sheet with uniform circular holes by employing an equivalent continuum approach, which is then applied to examine the plastic deformation of the perforated sheet with non-uniform circular holes. The analytical results predicted by the theory, including those for the apparent yield stresses and strain ratios, are verified by the results obtained from the finite element analysis and also from experiments.

scholarly journals Modeling of Size Effects in Bending of Perforated Cosserat Plates

2017 ◽  
Vol 2017 ◽  
pp. 1-19 ◽  
Author(s):  
Roman Kvasov ◽  
Lev Steinberg
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Numerical Study ◽  
The Finite Element Method ◽  
Classical Elasticity ◽  
Element Analysis ◽  
Plate Deformation ◽  
The Finite Element Analysis ◽  
Circular Holes ◽  
Different Shapes

This paper presents the numerical study of Cosserat elastic plate deformation based on the parametric theory of Cosserat plates, recently developed by the authors. The numerical results are obtained using the Finite Element Method used to solve the parametric system of 9 kinematic equations. We discuss the existence and uniqueness of the weak solution and the convergence of the proposed FEM. The Finite Element analysis of clamped Cosserat plates of different shapes under different loads is provided. We present the numerical validation of the proposed FEM by estimating the order of convergence, when comparing the main kinematic variables with an analytical solution. We also consider the numerical analysis of plates with circular holes. We show that the stress concentration factor around the hole is less than the classical value, and smaller holes exhibit less stress concentration as would be expected on the basis of the classical elasticity.

Failure Criteria for Brittle Notched Specimens

2022 ◽  
Author(s):  
Young W. Kwon ◽  
Carlos Diaz-Colon ◽  
Stanley Defisher
Keyword(s):  
Elliptical Hole ◽  
Failure Criteria ◽  
Homogeneous Material ◽  
Carbon Fiber Composites ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Theoretical Predictions ◽  
Circular Holes ◽  
Failure Loads ◽  
Stress Models

Abstract Recently, new failure criteria were proposed for brittle materials to predict their failure loads regardless of the shapes of a notch or a crack in the material. This paper is to further evaluate the failure criteria for different shapes of notches and different materials. A circular hole, elliptical hole or crack-like slit with a different angle with respect to the loading direction was considered. Double circular holes were also studied. The materials studied were an isotropic material like polymethyl methacrylate (PMMA) as well as laminated carbon fiber composites. Both cross-ply and quasi-isotropic layup orientations were examined. The lamination theory was used for the composite materials so that they can be modelled as an anisotropic and homogeneous material. The test results were compared to the theoretical predictions using the finite element analysis with 2-D plane stress models. Both theoretical failure stresses agreed well with the experimental data for the materials and notch geometries studied herein.

Modified Anisotropic Gurson Yield Criterion for Porous Ductile Sheet Metals

2000 ◽  
Vol 123 (4) ◽  
pp. 409-416 ◽  
Author(s):  
W. Y. Chien ◽  
J. Pan ◽  
S. C. Tang
Keyword(s):  
Finite Element ◽  
Closed Form ◽  
Yield Criterion ◽  
Plastic Anisotropy ◽  
Matrix Material ◽  
Plastic Behavior ◽  
Computational Results ◽  
Sheet Metals ◽  
Element Analysis ◽  
The Matrix

The influence of plastic anisotropy on the plastic behavior of porous ductile materials is investigated by a three-dimensional finite element analysis. A unit cell of cube containing a spherical void is modeled. The Hill quadratic anisotropic yield criterion is used to describe the matrix normal anisotropy and planar isotropy. The matrix material is first assumed to be elastic perfectly plastic. Macroscopically uniform displacements are applied to the faces of the cube. The finite element computational results are compared with those based on the closed-form anisotropic Gurson yield criterion suggested in Liao et al. 1997, “Approximate Yield Criteria for Anisotropic Porous Ductile Sheet Metals,” Mech. Mater., pp. 213–226. Three fitting parameters are suggested for the closed-form yield criterion to fit the results based on the modified yield criterion to those of finite element computations. When the strain hardening of the matrix is considered, the computational results of the macroscopic stress-strain behavior are in agreement with those based on the modified anisotropic Gurson’s yield criterion under uniaxial and equal biaxial tensile loading conditions.

scholarly journals Calculation of fracture mechanic parameters via FEM for some cracked plates under different loads

2006 ◽  
Vol 28 (2) ◽  
pp. 83-93 ◽  
Author(s):  
Ngo Huong Nhu ◽  
Nguyen Truong Giang
Keyword(s):  
Inclined Crack ◽  
Gravity Dams ◽  
Element Analysis ◽  
Cracked Plates ◽  
Failure State ◽  
The Finite Element Analysis ◽  
Arbitrary Position ◽  
Characteristic Values ◽  
The Given ◽  
Good Agreement

This paper describes some results in analyzing cracked plates via FEM based on the procedures in CASTEM 2000 [1]. The basic methods for computing the crack parameters by the finite element analysis are presented. Some programs written by GIBIAN languages to solve problems for cracked plates are given. In possible cases, the numerical results are composed with analytical solution or testing result that gives a good agreement. The influence of plate configurations, the crack length, the external load type on the crack characteristic values are considered. The numerical analysis for inclined crack at angle and in arbitrary position of plate, the crack at hole in the plate, the crack of gravity dams are realized. The given results and programs can be applied to practical problems for controlling the brittle failure state of a structure.

Elasto-Plastic Analysis of a Miniature Circular Disk Bending Specimen

2006 ◽  
Author(s):  
Vishnu Verma ◽  
A. K. Ghosh ◽  
G. Behera ◽  
Kamal Sharma ◽  
R. K. Singh
Keyword(s):  
Plastic Deformation ◽  
Finite Element ◽  
Yield Stress ◽  
Material Properties ◽  
Stable Solution ◽  
Bending Test ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Plastic Behavior ◽  
Element Analysis

Miniature disk bending test is used to evaluate the mechanical behavior of irradiated materials and its properties — mainly ductility loss due to irradiation in steel. In Miniature Disk Bending Machine the specimen is firmly held between the two horizontal jaws of punch, and an indentor with spherical ball travels vertically. Researchers have observed reasonable correlations between values of the yield stress, strain hardening and ultimate tensile strength estimated from this test and mechanical properties determined from the uniaxial tensile test. Some methods for the analysis of miniature disk bending, proposed by various authors have been discussed in the paper. It is difficult to distinguish between the regimes of elastic and plastic deformation since local plastic deformation occurs for very small values of load when the magnitude of spatially averaged stress will be well below the yield stress. Also, the analytical solution for large amplitude, plastic deformation becomes rather unwieldy. Hence a finite element analysis has been carried out. The finite element model, considers contact between the indentor and test specimen, friction between various pairs of surfaces and elastic plastic behavior. The load is increased in steps and converged solution has been obtained and analysis terminated at a load beyond which a stable solution cannot be obtained. A sensitivity study has been carried out by varying the various parameters defining the material properties by ±10% around the base values. This study has been carried out to generate a data base for the load-deflection characteristics of similar materials from which the material properties can be evaluated by an inverse calculation. It is seen that the deflection obtained by analytical elastic bending theory is significantly lower than that obtained by the elasto-plastic finite element solution at relatively small values of load. The FE solution and experimental results are in reasonably good agreement.

scholarly journals The Usage of the Johnson-Cook Constitutive Model in the Finite Element Analysis of the Caulking Process

2019 ◽  
Vol 290 ◽  
pp. 03013
Author(s):  
Claudiu Rodean ◽  
Livia-Dana Beju ◽  
Gabriela Rusu ◽  
Mihai Popp
Keyword(s):  
Finite Element Analysis ◽  
Plastic Deformation ◽  
World Wide ◽  
Cost Effective ◽  
Element Analysis ◽  
Plastic Deformations ◽  
Current State ◽  
The Finite Element Analysis ◽  
Cost Efficient ◽  
Deformation Models

The present paper highlights the importance of generating a model for analysing the caulking process. The caulking operation is a fast, cost-efficient, cost-effective way of assembling, which is currently less studied in world-wide papers. The operation is at the border between plastic deformation and cutting process. It is therefore necessary to create a model to describe the process. In the paper are presented the main examples of applications, the main parameters that characterize the process, the current state of the cutting and plastic deformation models. After the analysis we concluded that the most valuable model for describing plastic deformations is the Johnson-Cook model. This information is the basis for developing a model for describing the caulking process.

scholarly journals Series-Based Solution for Analysis of Simply Supported Rectangular Thin Plate with Internal Rigid Supports

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Abubakr E. S. Musa ◽  
Husain J. Al-Gahtani
Keyword(s):  
Analytical Solution ◽  
Bending Moment ◽  
Accurate Solution ◽  
Rectangular Plates ◽  
Compatibility Conditions ◽  
Element Analysis ◽  
Simply Supported ◽  
The Finite Element Analysis ◽  
Rigid Supports ◽  
The Given

In this study, Navier’s solution for the analysis of simply supported rectangular plates is extended to consider rigid internal supports. The proposed method offers a more accurate solution for the bending moment at the critical section and therefore serves as a better analytical solution for design purposes. To model the plate-support interaction, the patched areas representing the contact between the plate and supports are divided into groups of cells. The unknown internal reactions at the centers of the divided cells are obtained by satisfying the compatibility conditions at the centers of the cells. Three numerical examples are presented to demonstrate the accuracy of the proposed analytical solution. The given examples reveal good agreements with those obtained by the finite element analysis. In addition, they show the advantage of the new solution as compared to the existing analytical solution which inaccurately estimates the location and magnitude of the maximum bending moment.

Process Induced Stresses of a Flip-Chip Packaging by Sequential Processing Modeling Technique

1998 ◽  
Vol 120 (3) ◽  
pp. 309-313 ◽  
Author(s):  
J. Wang ◽  
Z. Qian ◽  
S. Liu
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Field ◽  
Flip Chip ◽  
Residual Stress Field ◽  
Element Analysis ◽  
Sequential Processing ◽  
The Finite Element Analysis ◽  
Flip Chip Packaging ◽  
The Given

In this paper, a nonlinear finite element framework was established for processing mechanics modeling of flip-chip packaging assemblies and relevant layered manufacturing. In particular, topological change was considered in order to model the sequential steps during the flip-chip assembly. Geometric and material nonlinearity, which includes the viscoelastic properties of underfill and the viscoplastic properties of solder alloys, were considered. Different stress-free temperatures for different elements in the same model were used to simulate practical manufacturing process-induced thermal residual stress field in the chip assembly. As comparison, two FEM models (processing model and nonprocessing model) of the flip-chip package considered, associated with different processing schemes, were analyzed. From the finite element analysis, it is found that the stresses and deflections obtained from nonprocessing model are generally smaller than those obtained from the processing model due to the negligence of the bonding process-induced residual stresses and warpage. The stress values at the given point obtained from the processing model are about 20 percent higher than those obtained from the nonprocessing model. The deflection values at the given points obtained from the processing model are usually 25 percent higher than those obtained from the nonprocessing model. Therefore, a bigger error may be caused by using nonprocessing model in the analysis of process-induced residual stress field and warpage in the packaging assemblies.

Identification of Kinematic Hardening Material Parameters for Martensitic Steel Sheets

2016 ◽  
Vol 866 ◽  
pp. 186-190
Author(s):  
Jung Han Song ◽  
J.S. Park ◽  
C.A. Lee ◽  
H.Y. Kim ◽  
W.H. Choi
Keyword(s):  
Mechanical Behavior ◽  
Martensitic Steel ◽  
Yield Criterion ◽  
Kinematic Hardening ◽  
Uniaxial Tensile ◽  
Plastic Behavior ◽  
Element Analysis ◽  
Hardening Material ◽  
Compression Load ◽  
Material Parameters

The identification of the material models which are used in the finite element analysis for the forming operation and springback are very important in terms of accurate predictions. The aim of this paper is to characterize both the anisotropy and the hardening of the ultra-high strength steel such as martensitic steel (MS steel) in order to identify material parameters of constitutive equation, which able to reproduce the mechanical behavior. Uniaxial tensile tests were carried out for characterizing the anisotropic plastic behavior of the MS steel. Cyclic tests under tension-compression load were also carried out for characterizing the Bauschinger effect during reverse deformation. Yoshida-Uemori hardening model associated with orthotropic yield criterion Hill’s 1948 is used to represent the in-plane mechanical behavior of the martensitic steel. The resented results show a very good agreement between model predictions and experiments: flow stresses during loading and reverse loading are well reproduced.

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