The Estimation of Large Deflections of a Portal Frame Under Asymmetric Pulse Loading

1984 ◽  
Vol 51 (3) ◽  
pp. 494-500 ◽  
Author(s):  
J. L. Raphanel ◽  
P. S. Symonds
Keyword(s):  
Local Deformation ◽  
Elastic Response ◽  
Sensitive Material ◽  
Rigid Plastic ◽  
Finite Element Program ◽  
Perfectly Plastic ◽  
Portal Frame ◽  
Element Program ◽  
Loaded Column ◽  
Asymmetric Pulse

Modifications of a simple elastic-plastic technique [1-4] are shown which allow estimation of local deformation in the loaded column of a portal frame as well as the side-sway deflections of the frame. A wholly elastic response stage provides input to a simplified rigid-plastic solution, in which velocity patterns first of local and then of modal (side-sway) type occur, and which furnishes estimates of final plastic deflections. Maximum (elastic plus plastic) deflections are estimated by adding displacements corresponding to the elastic strain field defined by the stresses of the closing rigid-plastic mode. The method is described for perfectly plastic and for strain-rate sensitive material, and comparisons are shown here with values computed3 for both types of material by a finite element program. Emphasis in this paper is put on the inclusion of elastic and vicoplastic effects.

Modelling of Dynamic Recrystallization in Hot Working

2007 ◽  
Vol 340-341 ◽  
pp. 779-786
Author(s):  
Bing Ye Xu ◽  
Jie Qu ◽  
Quan Lin Jin ◽  
Han Xiong Huang
Keyword(s):  
Finite Element ◽  
Dynamic Recrystallization ◽  
Microstructure Evolution ◽  
Optimization Method ◽  
Experimental Result ◽  
Element Formulation ◽  
Rigid Plastic ◽  
Finite Element Program ◽  
Element Program ◽  
Updated Lagrangian

Dynamic recrystallization, on which grain size of the final forging depends mainly, is one of the most important microstructure evolution processes in moderate-to-low stacking fault energy metals. In this paper, the process of dynamic recrystallization is simulated by numerical method. The paper first gives a visco-plastic model considering dynamic recrystallization in detail; secondly gives the applied finite element formulation and compiles an finite element program in Visual Fortran 6.5 based on the updated Lagrangian formulation rigid-plastic finite element; thirdly the material parameters are identified through inverse analysis, based on the compiled finite element program and the developed global optimization method; at last, the compiled finite element program is applied to simulate the microstructure evolution caused by dynamic recrystallization, the calculated result agrees with the experimental result relatively well.

Finite Element Analysis of Metal Forming Processes on Personal Computers

1991 ◽  
Vol 113 (4) ◽  
pp. 441-445 ◽  
Author(s):  
Li-lai Yan ◽  
Song-qing Xu ◽  
Guo-ji Li
Keyword(s):  
Finite Element ◽  
Metal Forming ◽  
Industrial Applications ◽  
Rigid Plastic ◽  
Element Analysis ◽  
Finite Element Program ◽  
Forming Analysis ◽  
Element Program ◽  
Linear Problems ◽  
Shape Complexity

The main difficulty in running a rigid-plastic finite element program for metal forming analysis on a personal computer lies in the lengthy computation, typical of non-linear problems. To make the PC more acceptable for forming analyses in industrial applications, some measures have been proposed, such as using a higher order IVP solver and modifying the generation of the initial velocity field to account for the existence of rigid zones, if any. As a result, 2-D metal forming problems with moderate shape complexity can be solved on PCs within a reasonable length of time.

Application of an Eigenfunction Expansion Method in Plasticity

1974 ◽  
Vol 41 (2) ◽  
pp. 448-452 ◽  
Author(s):  
T. Wierzbicki
Keyword(s):  
Plastic Material ◽  
Expansion Method ◽  
Plastic Behavior ◽  
Sensitive Material ◽  
Rigid Plastic ◽  
Simple Method ◽  
Elastic Mode ◽  
Perfectly Plastic ◽  
Eigenfunction Expansion Method ◽  
Expansion Technique

Possibilities of extending the eigenvalue expansion method to dynamic problems for plastic continua and structures are examined. A model of a pseudo strain rate sensitive material is introduced as an approximation to the concept of rigid-perfectly plastic material. A simple method is then developed which parallels the familiar elastic mode expansion technique but yet retains the main features of rigid-plastic behavior. The accuracy of the method is discussed and comparison with previous theories is made. An illustrative example is presented.

scholarly journals Comparison between Experimental and 3D Finite Element Analysis of Reinforced and Partially Pre-Stressed Concrete Solid Beams Subjected to Combined Load of Bending, Torsion and Shear

2008 ◽  
Vol 5 (1) ◽  
pp. 79
Author(s):  
A. S. Alnuaimi
Keyword(s):  
Finite Element ◽  
Prestressed Concrete ◽  
Failure Load ◽  
Element Analysis ◽  
Finite Element Program ◽  
3D Finite Element ◽  
Combined Load ◽  
Perfectly Plastic ◽  
Non Linear ◽  
Element Program

This paper presents a non-linear analysis of three reinforced and two partially prestressed concrete solid beams based on a 20 node isoparametric element using an in-house 3D finite element program. Anon linear elastic isotropic model, proposed by Kotsovos, was used to model concrete behaviour, while steel was modelled as an embedded element exhibiting elastic-perfectly plastic response. Allowance was made for shear retention and for tension stiffening in concrete after cracking. Only in a fixed direction, smeared cracking modelling was adopted. The beams dimensions were 300x300 mm cross section, 3800 mm length and were subjected to combined bending, torsion and shear. Experimental results were compared with the non-linear predictions. The comparison was judged by load displacement relationship, steel strain, angle of twist, failure load, crack pattern and mode of failure. Good agreement was observed between the predicted ultimate load and the experimentally measured loads. It was concluded that the present program can confidently be used to predict the behaviour and failure load of reinforced and partially prestressed concrete solid beams subjected to a combined load of bending, torsion and shear. 

scholarly journals MULTISURFACE PLASTICITY MODELS UNDER YIELDING CONDITIONS/MULTISURFACE-PLASTIZITÄTS-MODELLE MIT ZUSAMMENGESETZTEN FLIESSBEDINGUNGEN

1999 ◽  
Vol 5 (5) ◽  
pp. 329-334
Author(s):  
Dagmar Hintze ◽  
Johannes Will
Keyword(s):  
Numerical Solutions ◽  
Numerical Algorithms ◽  
Jointed Rock ◽  
Implicit Integration ◽  
Integration Algorithm ◽  
Finite Element Program ◽  
Surface Plasticity ◽  
Perfectly Plastic ◽  
Implicit Integration Algorithm ◽  
Element Program

An implicit integration algorithm for arbitrary multi- surface plasticity is presented. This perfectly-plastic model uses isotrop and anisotrop Mohr-Coulomb criteria with tension-cutoff and associated or non-associated flow rules. So materials with anisotropic deformation and strength behaviour like intact rock with sets of joints can be described. With an extended Drucker-Prager-criterion for the isotrop material matrix this model can be used as well for modelling other materials such as masonry or concrete. Problems resulting from arbitrary multisurface yield criteria are discussed. Consistent numerical algorithms for robust numerical solutions are presented. The Multisurface plasticity model was implemented in a finite-element-program. The example of calculation of a dam on jointed rock mass shows the applicability and new possibilities for the description of anisotropic materials.

Friction Force and Stresses Analysis for Contact of Assembled Details

2006 ◽  
Vol 113 ◽  
pp. 334-338
Author(s):  
Z. Dreija ◽  
O. Liniņš ◽  
Fr. Sudnieks ◽  
N. Mozga
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Plastic Deformation ◽  
Friction Force ◽  
Sliding Friction ◽  
Friction Model ◽  
Contact Interface ◽  
Finite Element Program ◽  
Elastic Plastic ◽  
Element Program

The present work deals with the computation of surface stresses and deformation in the presence of friction. The evaluation of the elastic-plastic contact is analyzed revealing three distinct stages that range from fully elastic through elastic-plastic to fully plastic contact interface. Several factors of sliding friction model are discussed: surface roughness, mechanical properties and contact load and areas that have strong effect on the friction force. The critical interference that marks the transition from elastic to elastic- plastic and plastic deformation is found out and its connection with plasticity index. A finite element program for determination contact analysis of the assembled details and due to details of deformation that arose a normal and tangencial stress is used.

scholarly journals The impact of drilling and slitting construction on damage field: evolution characteristics in low-permeability coal seam

2021 ◽  
Vol 37 ◽  
pp. 205-215
Author(s):  
Heng Chen ◽  
Hongmei Cheng ◽  
Aibin Xu ◽  
Yi Xue ◽  
Weihong Peng
Keyword(s):  
Finite Element ◽  
Rock Mass ◽  
Damage Mechanics ◽  
Effective Strain ◽  
Secondary Development ◽  
Distribution Area ◽  
Finite Element Program ◽  
Element Program ◽  
Mining Face ◽  
The Impact

ABSTRACT The fracture field of coal and rock mass is the main channel for gas migration and accumulation. Exploring the evolution law of fracture field of coal and rock mass under the condition of drilling and slitting construction has important theoretical significance for guiding efficient gas drainage. The generation and evolution process of coal and rock fissures is also the development and accumulation process of its damage. Therefore, based on damage mechanics and finite element theory, the mathematical model is established. The damage variable of coal mass is defined by effective strain, the elastoplastic damage constitutive equation is established and the secondary development of finite element program is completed by FORTRAN language. Using this program, the numerical simulation of drilling and slitting construction of the 15-14120 mining face of Pingdingshan No. 8 Mine is carried out, and the effects of different single borehole diameters, different kerf widths and different kerf heights on the distribution area of surrounding coal fracture field and the degree of damage are studied quantitatively. These provide a theoretical basis for the reasonable determination of the slitting and drilling arrangement parameters at the engineering site.

Mechanical Property Analysis and Numerical Simulation of Honeycomb Sandwich Structure’s Core

2013 ◽  
Vol 631-632 ◽  
pp. 518-523 ◽  
Author(s):  
Xiang Li ◽  
Min You
Keyword(s):  
Numerical Simulation ◽  
Elastic Constants ◽  
Sandwich Structure ◽  
Optimization Design ◽  
Simulation Analysis ◽  
Finite Element Program ◽  
Honeycomb Sandwich ◽  
Calculation Results ◽  
Element Program ◽  
Typical Satellite

Owing to the lack of a good theory method to obtain the accurate equivalent elastic constants of hexagon honeycomb sandwich structure’s core, the paper analyzed mechanics performance of honeycomb sandwich structure’s core and deduced equivalent elastic constants of hexagon honeycomb sandwich structure’s core considering the wall plate expansion deformation’s effect of hexagonal cell. And also a typical satellite sandwich structure was chose as an application to analyze. The commercial finite element program ANSYS was employed to evaluate the mechanics property of hexagon honeycomb core. Numerical simulation analysis and theoretical calculation results show the formulas of equivalent elastic constants is correct and also research results of the paper provide theory basis for satellite cellular sandwich structure optimization design.

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