A Study on the Material Modeling of a Robot Polyurethane Stopper

2009 ◽  
Author(s):  
Kyukwon Bang ◽  
Taewung Kim ◽  
Hyun-Yong Jeong
Keyword(s):  
Finite Element ◽  
Shear Test ◽  
Pure Shear ◽  
Material Model ◽  
Tension Test ◽  
Material Behavior ◽  
Prony Series ◽  
Material Constants ◽  
Torsion Vibration ◽  
Element Simulation

Polyurethane stoppers are used to protect heavy parts from damage in case of an unpredicted impact between parts in a robot. In order to evaluate the performance of a polyurethane stopper during impact, it was necessary to model the material behavior. Thus, the compression test, the tension test, the pure shear test, the torsion vibration test were conducted, and the hyperelastic material constants and viscoelastic material constants (Prony series parameters) were determined. Finite element simulations for the tests were conducted to check whether the material model adequately represented the material behavior. In addition, a finite element simulation for an impact between a part of a robot and a stopper was conducted to evaluate the performance of a stopper.

Effects of the Flow Stress in Finite Element Simulation of Machining Inconel 718 Alloy

2014 ◽  
Vol 611-612 ◽  
pp. 1210-1216 ◽  
Author(s):  
Farshid Jafarian ◽  
Mikel Imaz Ciaran ◽  
Pedro José Arrazola ◽  
Luigino Filice ◽  
Domenico Umbrello ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Simulation ◽  
Inconel 718 ◽  
Orthogonal Cutting ◽  
Material Model ◽  
Material Behavior ◽  
Machining Process ◽  
Inconel 718 Alloy ◽  
Element Simulation ◽  
Inconel 718 Superalloy

Inconel 718 superalloy is one of the difficult-to-machine materials which is employed widely in aerospace industries because of its superior properties such as heat-resistance, high melting temperature, and maintenance of strength and hardness at high temperatures. Material behavior of the Inconel 718 is an important challenge during finite element simulation of the machining process because of the mentioned properties. In this regard, various constants for Johnson–Cook’s constitutive equation have been reported in the literature. Owing to the fact that simulation of machining process is very sensitive to the material model, in this study the effect of different flow stresses were investigated on outputs of the orthogonal cutting process of Inconel 718 alloy. For each model, the predicted results of cutting forces, chip geometry and temperature were compared with experimental results of the previous work at the different feed rates. After comparing the results of the different models, the most suitable Johnson–Cook’s material model was indentified. Obtained results showed that the selected material model can be used reliably for machining simulation of Inconel 718 superalloy.

Texture Based Finite Element Simulation of a Two-Step Can Forming Process

2012 ◽  
Vol 504-506 ◽  
pp. 655-660 ◽  
Author(s):  
Vedran Glavas ◽  
Thomas Böhlke ◽  
Dominique Daniel ◽  
Christian Leppin
Keyword(s):  
Finite Element ◽  
Finite Element Simulation ◽  
Plastic Material ◽  
Large Strain ◽  
Material Model ◽  
Material Behavior ◽  
Flow Rule ◽  
Forming Process ◽  
Aluminum Sheets ◽  
Element Simulation

Aluminum sheets used for beverage cans show a significant anisotropic plastic material behavior in sheet metal forming operations. In a deep drawing process of cups this anisotropy leads to a non-uniform height, i.e., an earing profile. The prediction of this earing profiles is important for the optimization of the forming process. In most cases the earing behavior cannot be predicted precisely based on phenomenological material models. In the presented work a micromechanical, texture-based model is used to simulate the first two steps (cupping and redrawing) of a can forming process. The predictions of the earing profile after each step are compared to experimental data. The mechanical modeling is done with a large strain elastic visco-plastic crystal plasticity material model with Norton type flow rule for each crystal. The response of the polycrystal is approximated by a Taylor type homogenization scheme. The simulations are carried out in the framework of the finite element method. The shape of the earing profile from the finite element simulation is compared to experimental profiles.

Large Strain Viscoelastic Constitutive Models for Rubber, Part II: Determination of Material Constants

1995 ◽  
Vol 68 (2) ◽  
pp. 230-247 ◽  
Author(s):  
Claudia J. Quigley ◽  
Joey Mead ◽  
Arthur R. Johnson
Keyword(s):  
Finite Element ◽  
Large Strain ◽  
Strain Relaxation ◽  
Small Strain ◽  
Material Behavior ◽  
Prony Series ◽  
Relaxation Data ◽  
Material Constants ◽  
Tension And Compression ◽  
Step Strain

Abstract A method for determining material constants in large strain viscoelastic materials was demonstrated for a highly saturated nitrile rubber. Material constant selection was based on viscoelastic stress relaxation data at small and large strains, under both tension and compression, and was constrained to assure Drucker stability. Assuming that the viscoelastic strain energy function was both time and strain separable, a Prony series was constructed for the time dependent material constants. For comparison, four different Prony series were developed from collocation methods and a nonlinear regression analysis, each separately based on either large or small tensile strain relaxation data. In addition, a final Prony series was constructed from dynamic data. These Prony series were included in this comparison to judge their ability to predict both large and small strain material behavior. Finite element analyses of large and small step-strain relaxation tests and a single cycle hysteresis loop at large deformations were performed for each set of Prony series. The results were then compared to experimental behavior. The Prony series based on the constrained method accurately predicted step-strain relaxation behavior at all strain levels, for both tension and compression. The finite element results for the other Prony series show that large strain material behavior was best predicted by those Prony series based on large strain material behavior. Similar findings were found for small strain material behavior. The constrained Prony series and the two large strain based Prony series best modeled the experimental hysteresis loop.

scholarly journals Small Caliber Bulletproof Test of Warships’ Hulls

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3848
Author(s):  
Radosław Kiciński ◽  
Andrzej Kubit
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Boundary Conditions ◽  
Finite Element Method Simulation ◽  
Material Model ◽  
Experimental Results ◽  
Material Constants ◽  
Steel Core ◽  
Calculation Results ◽  
Simulation Results

The article presents the characteristics of 1.3964 steel and the results of firing a 7.62 mm projectile with a steel core. A simplified Johnson–Cook material model for steel and projectile was used. Then, a FEM (finite element method) simulation was prepared to calibrate the material constants and boundary conditions necessary to be used in simulations of the entire hull model. It was checked how projectile modeling affects the FEM calculation results. After obtaining the simulation results consistent with the experimental results, using the model of a modern minehunter, the resistance of the ship’s hull to penetration by a small-caliber projectile was tested.

Finite element simulation of fracture toughness testing of 20MnMoNi55 steel and the effect of loading rate on reference temperature

2020 ◽  
pp. 146442072095667
Author(s):  
Swagatam Paul ◽  
Snehasish Bhattacharjee ◽  
Sanjib Kumar Acharyya ◽  
Prasanta Sahoo
Keyword(s):  
Fracture Toughness ◽  
Finite Element ◽  
Finite Element Simulation ◽  
Loading Rate ◽  
Flow Characteristics ◽  
Material Model ◽  
Compact Tension ◽  
Reference Temperature ◽  
Viscoplastic Material ◽  
Element Simulation

Fracture toughness of ferritic steel in the ductile-to-brittle transition zone is scattered and probabilistic owing to embrittlement. Use of master curve along with the reference temperature ( T0) adopted in ASTM E-1921 is widely accepted for characterization of this embrittlement. Reference temperature is a measure of embrittlement in the temperature scale. Factors affecting fracture toughness like geometry and loading rate are expected to influence the reference temperature. In the present study, the role of the loading rate on the reference temperature for 20MnMoNi55 steel is assessed experimentally using compact tension C(T) and three-point bend (TPB) specimens. Finite element simulation of tests at different loading rates and cryogenic temperature are carried out using a suitable viscoplastic material model that incorporates flow characteristics of the material for varying displacement rates and cryogenic temperatures. Results from simulation studies are compared with experimental ones.

The role of material model in the finite element simulation of high-speed machining of Ti6Al4V

2016 ◽  
Vol 230 (17) ◽  
pp. 2959-2967 ◽  
Author(s):  
Chong-Yang Gao ◽  
Liang-Chi Zhang ◽  
Peng-Hui Liu
Keyword(s):  
Finite Element ◽  
Finite Element Simulation ◽  
High Speed ◽  
Material Model ◽  
Machining Process ◽  
High Speed Machining ◽  
Serrated Chip ◽  
Finite Element Program ◽  
Element Simulation ◽  
Improved Model

This paper provides a comprehensive assessment on some commonly used thermo-viscoplastic constitutive models of metallic materials during severe plastic deformation at high-strain rates. An hcp model previously established by us was improved in this paper to enhance its predictability by incorporating the key saturation characteristic of strain hardening. A compensation-based stress-updating algorithm was also developed to introduce the new hcp model into a finite element program. The improved model with the developed algorithm was then applied in finite element simulation to investigate the high-speed machining of Ti6Al4V. It was found that by using different material models, the simulated results of cutting forces, serrated chip morphologies, and residual stresses can be different too and that the improved model proposed in this paper can be applied to simulate the titanium alloy machining process more reliably due to its physical basis when compared with some other empirical Johnson–Cook models.

Effect of Material Model on Finite Element Modeling of Aerospace Alloys

2013 ◽  
Vol 554-557 ◽  
pp. 151-156 ◽  
Author(s):  
Mehdi Saboori ◽  
Javad Gholipour ◽  
Henri Champliaud ◽  
Augustin Gakwaya ◽  
Jean Savoie ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Material Model ◽  
Constitutive Laws ◽  
Material Behavior ◽  
Constitutive Law ◽  
Expansion Process ◽  
Free Expansion ◽  
Element Modeling ◽  
Bulge Height

Increasing acceptance and use of hydroforming technology within the aerospace industry requires a comprehensive understanding of critical issues such as the material characteristics, friction condition and hydroformability of the material. Moreover, the cost of experiments that can be reduced by accurate finite element modeling (FEM), which entails the application of adapted constitutive laws for reproducing with confidence the material behavior. In this paper, the effect of different constitutive laws on FEM of tubular shapes is presented. The free expansion process was considered for developing the FEM. Bulge height, thickness reduction and strains were determined at the maximum bulge height using different constitutive models, including Hollomon, Ludwik, Swift, Voce, Ludwigson. In order to minimize the effect of friction, the free expansion experiments were performed with no end feeding. The simulation results were compared with the experimental data to find the appropriate constitutive law for the free expansion process.

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