Elastoplastic Analysis of a Miniature Circular Disk Bending Specimen

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Vishnu Verma ◽  
A. K. Ghosh ◽  
G. Behera ◽  
Kamal Sharma ◽  
R. K. Singh
Keyword(s):  
Finite Element ◽  
Analytical Solutions ◽  
Material Properties ◽  
Finite Element Solution ◽  
Bending Test ◽  
Experimental Result ◽  
Strain Hardening Exponent ◽  
Plastic Behavior ◽  
Element Solution ◽  
Element Analysis

The miniature disk bending test is used to evaluate the mechanical behavior of irradiated materials and their properties (e.g., yield stress and strain hardening exponent) to determine mainly ductility loss in steel due to irradiation from the load-deflection behavior of the disk specimen. In the miniature disk bending machine the specimen is firmly held between the two horizontal jaws of punch, and an indentor with a spherical ball travels vertically. Analytical solutions for large amplitude plastic deformation become 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. This paper presents the load versus deflection results of a parametric study where the values of various parameters defining the material properties have been varied by ±10% around the base values. Some well-known analytical solutions to this problem have also been considered. It is seen that the deflection obtained by analytical elastic bending theory is significantly lower than that obtained by the elastoplastic finite element solution at relatively small values of load. The finite element solution has been compared with one experimental result and values are in reasonably good agreement. With these results it will be possible to determine the material properties from the experimentally obtained values of load and deflection.

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.

Scaling of Solutions for the Lateral Buckling of Elastic-Plastic Pipelines

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Ralf Peek ◽  
Heedo Yun
Keyword(s):  
Finite Element ◽  
Analytical Solutions ◽  
Finite Element Solution ◽  
Reference Solution ◽  
Element Solution ◽  
Lateral Buckling ◽  
Elastic Plastic ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic ◽  
The Moment

Analytical solutions for the lateral buckling of pipelines exist for the case when the pipe material remains in the linearly elastic range. However for truly high temperatures and/or heavier flowlines, plastic deformation cannot be excluded. One then has to resort to finite element analyses, as no analytical solutions are available. This paper does not provide such an analytical solution, but it does show that if the finite element solution has been calculated once, then that solution can be scaled so that it applies for any other values of the design parameters. Thus the finite element solution need only be calculated once and for all. Thereafter, other solutions can be calculated by scaling the finite element solution using simple analytical formulas. However, the shape of the moment-curvature relation must not change. That is, the moment-curvature relation must be a scaled version of the moment-curvature relation for the reference problem, where different scale factors may be applied to the moment and curvature. This paper goes beyond standard dimensional analysis (as justified by the Bucklingham Π theorem), to establish a stronger scalability result, and uses it to develop simple formulas for the lateral buckling of any pipeline made of elastic-plastic material. The paper includes the derivation of the scaling result, the application procedure, the reference solution for an elastic-perfectly plastic pipe, and an example to illustrate how this reference solution can be used to calculate the lateral buckling response for any elastic-perfectly plastic pipe.

scholarly journals Extracting elastic constitutive parameters using the VFM within peridynamics

2019 ◽  
Author(s):  
Rolland Delorme ◽  
Patrick Diehl ◽  
Ilyass Tabiai ◽  
Louis Laberge Lebel ◽  
Martin Levesque
Keyword(s):  
Finite Element ◽  
Displacement Field ◽  
Material Properties ◽  
Noise Analysis ◽  
Image Correlation ◽  
Bending Test ◽  
Virtual Fields Method ◽  
Element Analysis ◽  
Constitutive Parameters

This paper implements the Virtual Fields Method within the ordinary state based peridynamic framework to identify material properties. The key equations derived in this approach are based on the principle of virtual works written under the ordinary state based peridynamic formalism for two-dimensional isotropic linear elasticity. In-house codes including a minimization process have also been developed to implement the method. A three-point bending test and two independent virtual fields arbitrarily chosen are used as a case study throughout the paper. The numerical validation of the virtual fields method has been performed on the case study by simulating the displacement field by finite element analysis. This field has been used to extract the elastic material properties and compared them to those used as input in the finite element model, showing the robustness of the approach. Noise analysis and the effect of the missing displacement fields on the specimen’s edges to simulate digital image correlation limitations have also been studied in the numerical part. This work focuses on pre-damage properties to demonstrate the feasibility of the method and provides a new tool for using full-field measurements within peridynamics with a reduced calculation time as there is no need to compute the displacement field. Future works will deal with damage properties which is the main strength of peridynamics.

Prediction of Welding Residual Stresses, Crack Initiation and Creep Crack Driving Forces C(t) Within a Continuous Finite Element Solution

2010 ◽  
Author(s):  
D. P. Bray ◽  
R. J. Dennis ◽  
M. C. Smith
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Driving Forces ◽  
Welding Process ◽  
Creep Damage ◽  
Operating Conditions ◽  
Finite Element Solution ◽  
Element Solution ◽  
Element Analysis ◽  
Creep Crack

The work reported in this paper investigates the manufacture, through-life operation and cracked behaviour of an attachment weld in a UK AGR boiler. A structural assessment of the attachment weld was performed to demonstrate its integrity. This assessment made use of complex finite element analysis of both the welding process and postulated defects. A simulation of the welding process was performed in order to predict the residual stresses and hardened material state throughout the attachment weld. The welding simulation was performed in two stages since a butter weld was deposited prior to the attachment weld itself. The accumulation of creep damage was predicted during steady normal operating conditions for the lifetime of the component. A contour map of creep damage was used to postulate the location and size of hypothetical single and double edge surface cracks within the weld. These postulated cracks were then explicitly introduced into the finite element model. The crack tip stress parameter C(t) was evaluated in order to predict the creep crack driving forces. The results from a cracked body simulation suggested that the creep crack driving force C(t) reduces as the crack grows, due to relief of the dominant welding residual stresses. The residual stress, creep damage and cracked body simulations have been brought together into a novel continuous finite element solution. The results can be used to support a safety case for continued operation of existing plant.

Comparison of Flexural Behaviour of Composite FRP with UHPC I-Beam Using Finite Element Analysis

2021 ◽  
Vol 1042 ◽  
pp. 151-156
Author(s):  
Siti Shahirah Saidin ◽  
Adiza Jamadin ◽  
Sakhiah Abdul Kudus ◽  
Norliyati Mohd Amin
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Construction Materials ◽  
Flexural Behavior ◽  
Advanced Materials ◽  
Bending Test ◽  
Fiber Reinforced Polymers ◽  
Experimental Result ◽  
Beam Model ◽  
Element Analysis

Concrete can be considered as the ultimate construction material since it is the most widely used in the construction materials due to its extensive strength and reasonable cost. Recent years, large investments have been spent for studies on the new advanced materials to enhance the performance and functionality of conventional concrete especially for bridge structure. The application of Ultra-high-performance concrete (UHPC) as advanced materials in bridge application is well established since it able to construct 100m long highway bridge without reinforcement, while fiber reinforced polymers (FRP) required some studies on the optimum composition for bridge application. In this paper, A33 composite FRP from the previous research is studied under 4-point bending test to study the flexural behavior and compared to the UHPC. Three-dimensional finite element analysis of FRP and UHPC I-beam are modelled using Abaqus software to determine and compare the beam deflection and stress. The deflection and stress UHPC and FRP I-beam model being validated with experimental result of four-point bending test and theoretical of equivalent method in previous research. The results from the analytical and experimental are compared and shows good agreements. The presented modeling offers an economical and efficient tool to investigate the structural performance of FRP and UHPC in construction materials.

scholarly journals Evaluation of ultimate bending moment of circular concrete–filled double skin steel tubes using finite element analysis

2019 ◽  
Vol 13 (1) ◽  
pp. 21-32
Author(s):  
Vu Quang Viet ◽  
Hoang Ha ◽  
Pham Thai Hoan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Bending Moment ◽  
Bending Test ◽  
Experimental Result ◽  
Fe Model ◽  
Shear Connector ◽  
Steel Tubes ◽  
Element Analysis ◽  
Double Skin

In this study, the ultimate bending moment of circular concrete-filled double skin steel tubes (CFDSTs) was investigated. A CFDSTs made of two concentric circular steel tubes with concrete infill and M16 shear connector system was fabricated. The four-point bending test of the 10 m long CFDST consisting of outer and inner steel tubes with 914.4 mm and 514.4 mm in diameter, respectively, was carried out and the ultimate bending moment of the CFDST was investigated. A finite element (FE) simulation of the CFDSTs subjected to bending was developed using the commercial software ABAQUS and the accuracy of the developed FE model was verified by comparing to the experimental result. The ultimate bending moment of CFDSTs was then evaluated with respect to different concrete infill compressive strengths and yield strengths of the steel tubes. The corresponding design ultimate bending moments of the CFDST with regard to the design codes AISC and EC4 were also computed. The results revealed that EC4 and AISC can accurately predict the ultimate moment capacities of the CFDST with shear connector. Keywords: ultimate bending moment; concrete-filled double skin tube; shear connector system; finite element analysis. Received 19 November 2018, Revised 04 January 2019, Accepted 04 January 2019

Scaling of Solutions for the Lateral Buckling of Elastic-Plastic Pipelines

2004 ◽  
Author(s):  
Ralf Peek ◽  
Heedo Yun
Keyword(s):  
Finite Element ◽  
Analytical Solutions ◽  
Finite Element Solution ◽  
Reference Solution ◽  
Element Solution ◽  
Lateral Buckling ◽  
Elastic Plastic ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic ◽  
The Moment

Analytical solutions for the lateral buckling of pipelines exist for the case when the pipe material remains in the linearly elastic range. However for truly high temperatures and/or heavier flowlines, plastic deformation cannot be excluded. One then has to resort to finite element analyses, as no analytical solutions are available. This paper does not provide such an analytical solution, but it does show that if the finite element solution has been calculated once, then that solution can be scaled so that it applies for any other values of the design parameters. Thus the finite element solution need only be calculated once and for all. Thereafter, other solutions can be calculated by scaling the finite element solution using simple analytical formulae. The only significant limitation is that the shape of the moment-curvature relation must not change. I.e. the moment-curvature relation for the problem to be solved must be a scaled version of the moment-curvature relation for the reference problem, where different scale factors may be applied to the moment and curvature. This paper goes beyond standard dimensional analysis (as justified by the Bucklingham Π theorem), to establish a stronger scalability result, and uses it to develop simple formulae for the lateral buckling of any pipeline made of elastic-plastic material. The paper includes the derivation of the scaling result, the application procedure, the reference solution for an elastic-perfectly plastic pipe, and an example to illustrate how this reference solution can be used to calculate the lateral buckling response for any elastic-perfectly plastic pipe.

A Method to Calculate Volumetric Integral Averages From a Finite Element Solution

2000 ◽  
Author(s):  
Echo M. Miller ◽  
Peter S. Donzelli ◽  
Robert L. Spilker
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Articular Cartilage ◽  
Mechanical Behavior ◽  
Material Property ◽  
Finite Element Solution ◽  
Element Solution ◽  
Element Analysis ◽  
Parametric Studies ◽  
Biphasic Finite Element

Abstract The inhomogeneity and anisotropy of articular cartilage has been experimentally verified, but little has been done to quantify the effects of such material variation on mechanical behavior. We present a method to calculate volume-averaged quantities over tissue regions, used in conjunction with a 3D biphasic finite element analysis. Such average quantities can be used in parametric studies of different material property models, readily permitting statistical comparisons that are difficult with point-wise quantities.

Finite-Element Solution of Added Mass and Damping of Oscillation Rods in Viscous Fluids

1979 ◽  
Vol 46 (3) ◽  
pp. 519-523 ◽  
Author(s):  
C.-I. Yang ◽  
T. J. Moran
Keyword(s):  
Finite Element ◽  
Viscous Fluid ◽  
Interpolation Method ◽  
Reaction Force ◽  
Closed Form Solution ◽  
Added Mass ◽  
Form Solution ◽  
Finite Element Solution ◽  
Element Solution ◽  
Element Analysis

This paper presents a finite-element analysis for the cylindrical rods oscillating periodically in an incompressible viscous fluid. A system of discretized equation is obtained from the appropriate Navier-Stokes and continuity equations through Galerkin’s process. The basic unknowns are velocity and pressure. A mixed interpolation method is used. The added mass and viscous damping coefficients which characterize the fluid reaction force due to the rods oscillation can be obtained through a line integration of stress and pressure around the circumference of the rods. For the special case of a cylindrical rod oscillating in a viscous fluid enclosed by a rigid, concentric cylindrical shell, the finite-element solution agrees well with the analytical closed-form solution, which, in turn, has been verified experimentally [1].

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