Study on “Single Factor” Material Model Used in Finite Element Simulation of High Speed Cutting of Mo-Cr Cast Iron

2010 ◽  
Vol 29-32 ◽  
pp. 365-369
Author(s):  
Yong Yang ◽  
Cheng Jun Chen ◽  
Chang He Li

Theoretical analysis and material experiment are employed to study the “single factor” material model. Based on the dislocation theory, an analysis shows that material model is deeply affected by temperature. By the least squares best fit to experimental data, material parameters are found. Experiment curves analysis and material parameters comparison show that the material parameters of “single factor” model of Mo-Cr cast iron are temperature dependent. Using the mathematical mapping between material parameters and temperature, the “single factor” material model of Mo-Cr cast iron is established, which is proven to be right by comparing with experimental measurements. This work provides a useful insight for understanding the material model and helps to develop further finite element simulation of high speed cutting process of Mo-Cr cast iron.

2013 ◽  
Vol 579-580 ◽  
pp. 202-207
Author(s):  
Guo He Li ◽  
Hou Jun Qi ◽  
Bing Yan

For the high speed cutting process of hardened 45 steel (45HRC), a finite element simulation of cutting deformation, cutting force and cutting temperature is finished with the large general finite element software ABAQUS. Through the building of geometry model, material model and heat conduction model, also the determination of boundary conditions, separation rule and friction condition, a thermal mechanical coupling finite element model of high speed cutting for hardened 45 steel is built. The serrated chip, cutting force and cutting temperature can be predicted. The comparison of experiment and simulation shows the validity of the model. The influence of cutting parameters on cutting process is investigated by the simulation under different cutting depthes and rake angles. The results show that as the increase of rake angle, the segment degree, cutting force and cutting temperature decrease. But the segment degree, also the cutting force and cutting temperature increase with the increase of cutting depth. This study is useful for the selection of cutting parameters of hardened steel.


Author(s):  
Chong-Yang Gao ◽  
Liang-Chi Zhang ◽  
Peng-Hui Liu

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.


2020 ◽  
Vol 0 (12) ◽  
pp. 10-16
Author(s):  
V.V. Avtaev ◽  
◽  
D. V. Grinevich ◽  
A. V. Zavodov

Yielding tests of VTI-4 alloy specimens have been carried out at temperature 1010 °C under conditions of high-speed loading. Based on the test results the modulus of elasticity as well as axial and radial residual deformation values in the end and central zones for each loading stage were determined. Fitting criteria for finite element simulation and the experiment are proposed with tracing VTI-4 alloy diagram deformation at temperature 1010 °C and strain rate of 2.5 sec–1. As a result of finite element simulation the relationship between the material structures obtained during high-speed yielding and the deflected modes in different zones was determined.


Author(s):  
Swagatam Paul ◽  
Snehasish Bhattacharjee ◽  
Sanjib Kumar Acharyya ◽  
Prasanta Sahoo

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.


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