Design of large-deformation steady elastoplastic manufacturing processes. Part I: a displacement-based reference frame formulation

2000 ◽  
Vol 49 (7) ◽  
pp. 899-932 ◽  
Author(s):  
D. Balagangadhar ◽  
D. A. Tortorelli
Keyword(s):  
Large Deformation ◽  
Reference Frame ◽  
Manufacturing Processes ◽  
Displacement Based

Simulation of a Cantilevered Thin-Elastic Plate with Large Deformation Subjected to Axial Flow

2014 ◽  
Vol 1065-1069 ◽  
pp. 2069-2075
Author(s):  
Wei Bin Hong ◽  
Chang Qing Guo ◽  
Ye Zhou Sheng
Keyword(s):  
Flow Velocity ◽  
Large Deformation ◽  
Elastic Plate ◽  
Stokes Equations ◽  
Axial Flow ◽  
Navier Stokes ◽  
Thin Elastic Plate ◽  
Two Dimensional ◽  
Vibration Responses ◽  
Displacement Based

The instability and dynamics behavior of a cantilevered thin-elastic plate with large deformation subjected to axial flow is studied numerically. The structural dynamics equation is discretized by isoparametric displacement-based finite, and the motion of a continuous fluid domain is governed by two-dimensional incompressible viscous Navier-Stokes equations, which discretized by finite volume method. The two-dimensional numerical model of two-way fluid-structure coupling is established combined with moving mesh technology, realizing the interaction of thin-elastic plate and axial fluid. Firstly, under given different flow velocity, the stability of limit-cycle oscillations has been studied through Hopf bifurcation, time trace, vibration responses. Secondly, the fluid domain features are analyzed qualitatively by separately comparing with vorticity under given different flow velocity, and cloud diagram of pressure and velocity are also analyzed at U=3.6m/s.

F-Bar Aided Edge-Based Smoothed Finite Element Method with 4-Node Tetrahedral Elements for Static Large Deformation Elastoplastic Problems

2019 ◽  
Vol 16 (05) ◽  
pp. 1840010 ◽  
Author(s):  
Yuki Onishi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Large Deformation ◽  
Element Formulation ◽  
Tetrahedral Elements ◽  
Smoothed Finite Element Method ◽  
New Type ◽  
Displacement Based ◽  
Edge Based ◽  
Element Method

A new type of smoothed finite element method (S-FEM), F-barES-FEM-T4, is demonstrated in static large deformation elastoplastic cases. F-barES-FEM-T4 combines the edge-based S-FEM (ES-FEM) and the node-based S-FEM (NS-FEM) for 4-node tetrahedral (T4) elements with the aid of the F-bar method in order to resolve the major issues of Selective ES/NS-FEM-T4. As well as most of the other S-FEMs, F-barES-FEM-T4 inherits pure displacement-based formulation and thus has no increase in DOF. Moreover, the cyclic smoothing procedure introduced in F-barES-FEM-T4 is effective to adjust the smoothing level so that pressure checkerboarding (oscillation) is suppressed reasonably. Some examples of static large deformation analyses for elastoplastic materials proof the excellent performance of F-barES-FEM-T4 in contrast to the conventional hybrid T4 element formulation.

Dynamic Mechanical Behavior of Titanium Ti-6Al-4V at Transient Large Deformation Manufacturing Processes

2007 ◽  
Author(s):  
J. Sun ◽  
Y. B. Guo
Keyword(s):  
Flow Stress ◽  
Mechanical Behavior ◽  
Large Deformation ◽  
Large Deformations ◽  
Model Parameters ◽  
Manufacturing Processes ◽  
Strain Rates ◽  
Dynamic Mechanical ◽  
Dynamic Mechanical Behavior ◽  
Jc Model

Titanium Ti-6Al-4V alloy has been widely used in the aerospace, biomedical, automobile and petroleum industries. However, Ti-6Al-4V is a typical difficult-to-process material owning to its unique physical and mechanical properties which are characterized by low thermal conductivity, low modulus of elasticity, and high yield strength at elevated temperatures. The rapidly rising demand for titanium components demands more efficient manufacturing processes. Material property of Ti-6Al-4V plays an important role in process design and optimization especially for transient large deformations processes such as forming and machining. However, the dynamic mechanical behavior is poorly understood and accurate predictive models have yet to be developed. To obtain meaningful results which reflect the physical mechanisms of large deformation processes, it is essential to study the dynamic mechanical behavior of Ti-6Al-4V. The Johnson-Cook (JC) model has shown to be effective for modeling strain-hardening behavior of metals and it is numerically robust and can easily be used in finite element simulation models. However, the determination of JC model parameters is determined mostly based on split Hopkinson bar pressure (SHPB) test at isothermal conditions, which is very different from those of transient large deformations characterized by quick and high temperature changes. This study focuses on the dynamic mechanical behavior of titanium in transient manufacturing processes. The mechanical behavior of Ti-6Al-4V at large strains and strain rates beyond the isothermal conditions has been studied using the JC model coupled with the adiabatic condition. Heat fraction coefficient and temperature parameter have great effect on Flow stress-strain relationship. A significant drop of the flow stress occurs at large deformations with high strain rates. The flow stress sensitivity to JC strength model parameters was also investigated. The effect of pressure-stress ratio on material failure strain has shown the material may exhibit super plasticity before failure at hydro compression mode.

A displacement-based reference frame formulation for steady-state thermo-elasto-plastic material processes

1999 ◽  
Vol 36 (16) ◽  
pp. 2397-2416 ◽  
Author(s):  
D. Balagangadhar ◽  
G.A. Dorai ◽  
D.A. Tortorelli ◽  
University of Illinois at Urbana-Champaign
Keyword(s):  
Steady State ◽  
Reference Frame ◽  
Plastic Material ◽  
Displacement Based

Practical Realization of a Reference System for Earth Dynamics by Satellite Methods

1975 ◽  
Vol 26 ◽  
pp. 341-380 ◽  
Author(s):  
R. J. Anderle ◽  
M. C. Tanenbaum
Keyword(s):  
Reference Frame ◽  
Polar Motion ◽  
Pole Position ◽  
Control Points ◽  
Significant Information ◽  
Crustal Motion ◽  
Average Reference ◽  
Future Data ◽  
Existing Data

AbstractObservations of artificial earth satellites provide a means of establishing an.origin, orientation, scale and control points for a coordinate system. Neither existing data nor future data are likely to provide significant information on the .001 angle between the axis of angular momentum and axis of rotation. Existing data have provided data to about .01 accuracy on the pole position and to possibly a meter on the origin of the system and for control points. The longitude origin is essentially arbitrary. While these accuracies permit acquisition of useful data on tides and polar motion through dynamio analyses, they are inadequate for determination of crustal motion or significant improvement in polar motion. The limitations arise from gravity, drag and radiation forces on the satellites as well as from instrument errors. Improvements in laser equipment and the launch of the dense LAGEOS satellite in an orbit high enough to suppress significant gravity and drag errors will permit determination of crustal motion and more accurate, higher frequency, polar motion. However, the reference frame for the results is likely to be an average reference frame defined by the observing stations, resulting in significant corrections to be determined for effects of changes in station configuration and data losses.

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