Designing Hot Working Processes of Nickel Base Superalloys Using FEM Simulation

2001 ◽  
Author(s):  
R. Kopp ◽  
M. Tschirnich ◽  
M. Wolske ◽  
J. Klöwer
Keyword(s):  
Testing Machine ◽  
Fem Simulation ◽  
Material Model ◽  
Hydraulic Testing ◽  
Compression Tests ◽  
Finite Element Program ◽  
Real Process ◽  
Forming Temperature ◽  
Element Program ◽  
Nickel Base

Knowledge of correct flow stress curves of Ni-based alloys at high temperatures is of essential importance for reliable plasto-mechanical simulations in materials processing and for an effective planning and designing of industrial hot forming schedules like hot rolling or forging. The experiments are performed on a computer controlled servo-hydraulic testing machine at IBF (Institute of Metal Forming). To avoid an inhomogeneous deformation due to the influence of friction and initial microstructure, a suitable specimen geometry and lubricant is used and a thermal treatment before testing has to provide a microstructure, similar to the structure of the material in the real process. The compression tests are performed within a furnace, which keeps sample, tools and surrounding atmosphere at the defined forming temperature. The uniaxial compressions were carried out in the range of strain rates between 0.001 and 50 s−1 and temperatures between 950 and 1280°C. Furthermore two-stage step tests are carried out to derive the work hardening and softening behaviour as well as the recrystallisation kinetics of the selected Ni-based alloys. At the end of this work a material model is adapted by the previously determined material data. This model is integrated into the Finite Element program LARSTRAN/SHAPE to calculate a forging process of the material Alloy 617.

Designing Hot Working Processes of Nickel-Based Superalloys Using Finite Element Simulation

2002 ◽  
Vol 124 (4) ◽  
pp. 931-935 ◽  
Author(s):  
R. Kopp ◽  
M. Tschirnich ◽  
M. Wolske ◽  
J. Klo¨wer
Keyword(s):  
Finite Element ◽  
Testing Machine ◽  
Material Model ◽  
Compression Tests ◽  
Finite Element Program ◽  
Softening Behavior ◽  
Real Process ◽  
Element Simulation ◽  
Forming Temperature ◽  
Element Program

Knowledge of correct flow stress curves of Ni-based alloys at high temperatures is of essential importance for reliable plastomechanical simulations in materials processing and for an effective planning and designing of industrial hot forming schedules like hot rolling or forging. The experiments are performed on a computer controlled servohydraulic testing machine at IBF. To avoid an inhomogeneous deformation due to the influence of friction and initial microstructure, a suitable specimen geometry and lubricant is used and a thermal treatment before testing has to provide a microstructure, similar to the structure of the material in the real process. The compression tests are performed within a furnace, which keeps sample, tools, and surrounding atmosphere on the defined forming temperature. The uniaxial compressions were carried out in the range of strain rates between 0.001 and 50s−1 and temperatures between 950 and 1280°C. Furthermore, two-stage step tests are carried out to derive the work hardening and softening behavior as well as the recrystallization kinetics of the selected Ni-based alloys. At the end of this work a material model is adapted by the previously determined material data. This model is integrated into the Finite Element program LARSTRAN/SHAPE to calculate a forging process of the material Alloy 617.

FEM Simulation of a Magnetic Shape Memory Foil Actuator Under Different Loading Conditions

2011 ◽  
Author(s):  
B. Krevet ◽  
M. Kohl ◽  
V. Pinneker
Keyword(s):  
Finite Element ◽  
Shape Memory ◽  
Fem Simulation ◽  
Material Model ◽  
Element Model ◽  
Magnetic Shape Memory ◽  
Finite Element Program ◽  
Model And Simulation ◽  
Element Program ◽  
Mechanical Spring

This paper presents a finite element model and simulation results on the performance of a novel linear actuator using the magnetic shape memory (MSM) effect in a Ni-Mn-Ga foil loaded by a mechanical spring. We present finite element simulations with a material model based on the thermodynamic Gibbs free energy in a finite element program (FEM) using beam elements, which is combined with an integral magnetic solver. The simulations qualitatively describe the observed tensile stress-dependence of magneto strain of a first demonstrator of a MSM foil actuator. We demonstrate that complete reversible cycles of the magnetic field induced strain are possible if the spring is preloaded to induce a prestress in the foil. The effect of inhomogeneous material on variant reorientation and corresponding magneto strain are discussed.

On Modeling the Mechanical Behavior of Amorphous Polymers for the Micro-Hot-Embossing of Microfluidic Devices

2008 ◽  
Author(s):  
Vikas Srivastava ◽  
Lallit Anand
Keyword(s):  
Three Dimensional ◽  
Amorphous Polymers ◽  
Hot Embossing ◽  
Compression Tests ◽  
Predictive Capability ◽  
Finite Element Program ◽  
Rate Dependent ◽  
Wide Range ◽  
Element Program ◽  
Simple Compression

In this paper, a brief summary of some of our recent work [1, 2] is presented, with the goal of developing an engineering science-based process-simulation capability for micro-hot-embossing of amorphous polymers. To achieve this goal: (i) a three-dimensional thermo-mechanically-coupled large deformation constitutive theory has been developed to model the temperature and rate-dependent elastic-viscoplastic response of amorphous polymers; (ii) the material parameters in the theory were calibrated by using new experimental data from a suite of simple compression tests on Zeonex-690R (cyclo-olefin polymer), that covers a wide range of temperatures and strain rates; (iii) the constitutive model was implemented in the finite element program ABAQUS/Explicit; and (iv) the predictive capability of the numerical simulation procedures were validated by comparing results from the simulation of a representative micro-hot-embossing process against corresponding results from a physical experiment.

Stability Analysis of Unsaturated Soil Slopes under Rainfall Infiltration

2012 ◽  
Vol 594-597 ◽  
pp. 126-129 ◽  
Author(s):  
Rong Fang Zhou ◽  
Xue Wen Lei ◽  
Qing Shan Meng ◽  
Cong Lin
Keyword(s):  
Unsaturated Soil ◽  
Equivalent Plastic Strain ◽  
Material Model ◽  
Rainfall Infiltration ◽  
Finite Element Program ◽  
Soil Material ◽  
Element Program ◽  
Stability Of Slope ◽  
Transient Seepage ◽  
The Stability

The principle of effective stress based on unsaturated soil material model and the boundary conditions of rainfall infiltration on the slope are introduced. The numerical model is built according to the example, and then the ABAQUS finite element program, which is combined with fluid-solid coupling, is used to simulate the problem of transient seepage field caused by rainfall infiltration. With the powerful post processing functions ability of ABAQUS program, we can observe the variation law with the time of pore-pressure distribution and displacement field and equivalent plastic strain. Moreover, the effect on the stability of slope under rainfall infiltration is analyzed.

Computer Aided Modeling of Deep-Drawing

2007 ◽  
Vol 344 ◽  
pp. 341-348
Author(s):  
Mehmet Ali Pişkin ◽  
Bilgin Kaftanoğlu
Keyword(s):  
Finite Element ◽  
Deep Drawing ◽  
Plastic Material ◽  
Yield Criterion ◽  
Shell Element ◽  
Material Model ◽  
Industrial Applications ◽  
Finite Element Program ◽  
Element Program ◽  
Von Mises

Deep-drawing operations are performed widely in industrial applications. It is very important for efficiency to achieve parts with no defects. In this work, a finite element method is developed to simulate deep-drawing operation including wrinkling. A four nodded five degree of freedom shell element is formulated. Isotropic elasto-plastic material model with Von Mises yield criterion is used. By using this shell element, the developed code can predict the bending behavior of workpiece besides membrane behavior. Simulations are carried out with four different element sizes. The thickness strain and nodal displacement values obtained are compared with results of a commercial finite element program and results of previously conducted experiments.

Finite Element Analysis of Synchronous Belt Tooth Failure

1993 ◽  
Vol 207 (2) ◽  
pp. 145-153 ◽  
Author(s):  
K W Dalgarno ◽  
A J Day ◽  
T H C Childs
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Material Model ◽  
Element Model ◽  
Element Analysis ◽  
Finite Element Program ◽  
Interface Elements ◽  
Dimensional Finite Element ◽  
Element Program ◽  
Critical Strains

This paper describes a finite element analysis of a synchronous belt tooth under operational loads and conditions with the objective of obtaining a greater understanding of belt failure by tooth root cracking through an examination of the strains within the facing fabric in the belt. The analysis used the ABAQUS finite element program, and was based on a two-dimensional finite element model incorporating a hyperelastic material model for the elastomer compound. Contact between the belt tooth face and the pulley groove was modelled using surface interface elements which allowed only compression and shear forces at the contact surfaces. It is concluded that the critical strains in the facing fabric of the belt, and therefore the belt life, are largely determined by the tangential loading condition on the belt teeth.

An Insight into the Effect of Deformation on Carbide Dissolution in the Band Structure of Bearing Steel

2013 ◽  
Vol 334-335 ◽  
pp. 171-176 ◽  
Author(s):  
Mitra Basirat ◽  
Hasse Fredriksson
Keyword(s):  
Band Structure ◽  
Volume Fraction ◽  
Testing Machine ◽  
Recovery Process ◽  
Hydraulic Testing ◽  
Bearing Steel ◽  
Dendritic Segregation ◽  
Compression Tests ◽  
Uphill Diffusion ◽  
Carbide Dissolution

Dendritic segregation in deformed samples remains in the form of band structure, which is a high-strained region. The present work investigates the effect of the uphill diffusion process, occurring during deformation, on the dissolution of carbide particles in the band structure. A series of hot compression tests are performed on the cast structure of bearing steel by using a hydraulic testing machine, MTS 810. Cylindrical specimens are deformed in a temperature range of 800°C to 900°C and at strain rates of 5s-1and 0.5s-1. In order to eliminate the recovery process, samples are immediately quenched after the compression. The microsegregation of Cr, Mo, Mn and Si are investigated in the band structure, which shows a tendency of uphill diffusion during deformation process. The results show that the volume fraction of carbides varies with the increased straining. The results also show that deformation causes the fragmentation, dispersion of pearlite in the dendrites and the dissolution of spheroidized carbides in the band structure.

Implementation of the Nonlocal Microplane Concrete Model Within an Explicit Dynamic Finite Element Program

1992 ◽  
Vol 45 (3S) ◽  
pp. S132-S139 ◽  
Author(s):  
William F. Cofer
Keyword(s):  
Finite Element ◽  
Strain Tensor ◽  
Material Model ◽  
Material Behavior ◽  
Concrete Material ◽  
Finite Element Program ◽  
Dynamic Finite Element ◽  
Weighted Integral ◽  
Element Program ◽  
Explicit Dynamic

The microplane concrete material model is based upon assumptions regarding the behavior of the material components. At any point, the response to the strain tensor on arbitrarily oriented surfaces is considered. Simple, softening stress-strain relationships are assumed in directions perpendicular and parallel to the surfaces. The macroscopic material behavior is then composed of the sum of the effects. The implementation of this model into the explicit, nonlinear, dynamic finite element program, DYNA3D, is described. To avoid the spurious mesh sensitivity that accompanies material failure, a weighted integral strain averaging approach is used to ensure that softening is nonlocal. This method is shown to be effective for limiting the failure zone in a concrete rod subjected to an impulse loading.

Calculation of Reloading Stress Relaxation Behavior Based on Creep Equations for 1Cr-0.5Mo-0.25V Steel

2013 ◽  
Vol 811 ◽  
pp. 131-134
Author(s):  
Wei Wei Zhang ◽  
Hong Xu
Keyword(s):  
Stress Relaxation ◽  
Material Model ◽  
Relaxation Behavior ◽  
National Research Institute ◽  
Time Intervals ◽  
Finite Element Program ◽  
Stress Relaxation Behavior ◽  
Proposed Model ◽  
Element Program ◽  
Good Agreement

In order to analyze the stress relaxation behavior under repeated loadings for 1Cr-0.5Mo-0.25V steel, a stress relaxation model based on creep equations has been developed. The model was implemented into the ANSYS finite element program in terms of user define material model. The calculated results were compared to the observed results of uniaxial reloading stress relaxation testing, which were performed by the National Research Institute for Metals of Japan (NRIM) for 1Cr-0.5Mo-0.25V stainless steel bolting material at 500°C. It was shown that the proposed model could be applied for the present data. The calculated residual stresses versus time curves were in good agreement with the observed for initial stress level of 297.1MPa at 500°C and for specific reloading time intervals of 24, 72, 240, and 720 hours.

Material Modeling and Springback Analysis Considering Tension/Compression Asymmetry of Flow Stresses

2014 ◽  
Vol 611-612 ◽  
pp. 33-40 ◽  
Author(s):  
Nobuyasu Noma ◽  
Toshihiko Kuwabara
Keyword(s):  
Dual Phase Steel ◽  
Testing Machine ◽  
Material Model ◽  
Tensile Tests ◽  
Yield Function ◽  
Test Material ◽  
Finite Element Analyses ◽  
Compression Tests ◽  
Springback Prediction ◽  
Tension Compression Asymmetry

In-plane tension/compression tests of a dual phase steel sheet with a tensile strength of 780 MPa were carried out using in-plane stress reversal testing machine. Remarkable tension/ compression asymmetry of flow stress (TCA) has been observed. Moreover, biaxial tensile tests using cruciform specimens were performed to measure contours of plastic work. The test material exhibited differential work hardening (DWH). In order to reproduce the TCA, an asymmetric quadratic yield function proposed by Verma et al. (2011) was used. The parameters of the yield function were changed as a function of reference plastic strain to reproduce the DWH. Furthermore, to assess the springback prediction accuracy of the developed model, a 3-point bending experiment and finite element analyses (FEA) were performed. It is concluded that the use of the material model that is capable of reproducing DWH and TCA is a must for a highly accurate FEA of springback.

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