scholarly journals Finite Element Modeling of Microstructural Changes in Hard Machining of SAE 8620

2019 ◽  
Vol 10 (1) ◽  
pp. 121 ◽  
Author(s):  
Serafino Caruso ◽  
Giovanna Rotella ◽  
Antonio Del Prete ◽  
Domenico Umbrello

Surface and subsurface microstructural characterization after machining operations is a topic of great interest for both academic and industrial research activities. This paper presents a newly developed finite element (FE) model able to describe microstructural evolution and dynamic recrystallization (DRX) during orthogonal hard machining of SAE 8620 steel. In particular, it predicts grain size and hardness variation by implementing a user subroutine involving a hardness-based flow stress and empirical models. The model is validated by comparing its output with the experimental results available in literature at varying the cutting speed, insert geometry and flank wear. The results show a good ability of the customized model to predict the thermo-mechanical and microstructural phenomena taking place during the selected processes.

Author(s):  
Serafino Caruso ◽  
Stano Imbrogno

AbstractGrain refinement by severe plastic deformation (SPD) techniques, as a mechanism to control microstructure (recrystallization, grain size changes,…) and mechanical properties (yield strength, ultimate tensile strength, strain, hardness variation…) of pure aluminium conductor wires, is a topic of great interest for both academic and industrial research activities. This paper presents an innovative finite element (FE) model able to describe the microstructural evolution and the continuous dynamic recrystallization (CDRX) that occur during equal channel angular drawing (ECAD) of commercial 1370 pure aluminium (99.7% Al). A user subroutine has been developed based on the continuum mechanical model and the Hall-Petch (H-P) equations to predict grain size variation and hardness change. The model is validated by comparison with the experimental results and a predictive analysis is conducted varying the channel die angles. The study provides an accurate prediction of both the thermo-mechanical and the microstructural phenomena that occur during the process characterized by large plastic deformation.


2016 ◽  
Vol 852 ◽  
pp. 304-310
Author(s):  
M.M. Thamizharasan ◽  
Y.J. Nithiya Sandhiya ◽  
K.S. Vijay Sekar ◽  
V.V. Bhanu Prasad

The application of Metal Matrix Composite (MMC) has been increasing due to its superior strength and wear characteristics but the major challenge is its poor machinability due to the presence of reinforcement in the matrix which is a hindrance during machining. The material behaviour during machining varies with respect to input variables. In this paper the effect of cutting speed during the orthogonal turning of A359/SiCp MMC with TiAlN tool insert is analysed by developing a 2D Finite Element (FE) model in Abaqus FEA code. The FE model is based on plane strain formulation and the element type used is coupled temperature displacement. The matrix material is modeled using Johnson–Cook (J-C) thermal elastic–plastic constitutive equation and chip separation is simulated using Johnson–Cook’s model for progressive damage and fracture with parting line. Particle material is considered to be perfectly elastic until brittle fracture. The tool is considered to be rigid. The FE model analyses the tool interaction with the MMC and its subsequent effects on cutting forces for different cutting speeds and feed rates. The chip formation and stress distribution are also studied. The FE results are validated with the experimental results at cutting speeds ranging from 72 – 188 m/min and feed rates ranging from 0.111 – 0.446 mm/rev at constant depth of cut of 0.5mm.


2004 ◽  
Vol 127 (3) ◽  
pp. 484-491 ◽  
Author(s):  
Jing Shi ◽  
C. Richard Liu

A material softening model based on thermal activation energy has been successfully established through tempering experiments in the first part of this study. To apply the model to predicting material softening in hard turned surfaces, the thermal history of work material is needed. In this part, a three-dimensional finite element (FE) model of machining hardened 52100 steel is constructed, and coupled thermal-stress analysis is performed to obtain the material thermal history. Then the material softening model uses the computed thermal history as input to predict the material hardness profiles along the depth into the machined surfaces. Overall, the prediction precisely catches the trend of hardness change along depth and agrees reasonably well with the hardness measurement. What’s more, the sensitivity of material softening to cutting parameters is investigated both quantitatively and qualitatively. Within the investigation range, it is observed that the increase of tool flank wear and feed rate produces severe material softening and a deeper softened layer, while the increase of cutting speed causes significant softening to the surface material but hardly changes the softened depth.


2021 ◽  
Author(s):  
SERAFINO CARUSO ◽  
Stano Imbrogno

Abstract Grain refinement by severe plastic deformation (SPD) techniques, as a mechanism to control microstructure (recrystallization, grain size changes,…) and mechanical properties (yield strength, ultimate tensile strength, strain, hardness variation…) of pure aluminium conductor wires, is a topic of great interest for both academic and industrial research activities. This paper presents an innovative finite element (FE) model able to describe the microstructural evolution and the continuous dynamic recrystallization (CDRX) that occur during equal channel angular drawing (ECAD) of commercial 1370 pure aluminium (99.7% Al). A user subroutine has been developed based on the continuum mechanical model and the Hall-Petch (H-P) equations to predict grain size variation and hardness change. The model is validated by comparison with the experimental results and a predictive analysis is conducted varying the channel die angles. The study provides an accurate prediction of both the thermo-mechanical and the microstructural phenomena that occur during the process characterised by large plastic deformation.


2013 ◽  
Author(s):  
Long Meng ◽  
Xueping Zhang ◽  
Anil K. Srivastava

Finite Element Analysis (FEA) is widely used to simulate machining processes. However, in general, it is time consuming, error-prone, and requires repeated efforts to establish a verified successful Finite Element (FE) model. To rapidly investigate the effects of parameters such as tool angle, feed rate, cutting speed, and temperatures generated during the machining process, an efficient approach is proposed in this paper. The technique has been used to achieve rapid FF simulation during turning and milling processes using Python language programming of Abaqus. Sub-model 1 is programmed to simulate the chip formation process in Abaqus/Explicit. Sub-model 2 is programmed to simulate the cooling spring-back process by importing the machined surface into Abaqus/Implicit. The proposed method is capable of simulating the chip morphology, stress, strain and temperature of the machining process with different parameters immediately. The established FE models are automatically solved in batch by programming script. Post-processing is programmed by Abaqus script to easily achieve and evaluate the simulation results. The Programmed FE models are validated in terms of the predicted chip morphology, cutting forces and residual stresses. This method is extraordinarily efficient saving more than 33% simulation time in comparison to existing FEA approach used for machining processes. Moreover, the script is concise, easy to debug, and effectively avoiding interactive mistakes. The rapid programming model provides a novel, efficiency and convenient approach to thoroughly investigate the effects of a large number of parameters on machining processes.


Author(s):  
Xueping Zhang ◽  
Shenfeng Wu ◽  
Heping Wang ◽  
C. Richard Liu

To explore the effects of cutting speed, feed rate and rake angle on chip morphology transition, a thermomechanical coupled orthogonal (2-D) finite element (FE) model is developed, and to determine the effects of tool nose radius and lead angle on hard turning process, an oblique (3-D) FE model is further proposed. Three one-factor simulations are conducted to determine the evolution of chip morphology with feed rate, rake angle, and cutting speed, respectively. The chip morphology evolution from continuous to saw-tooth chip is described by means of the variations of chip dimensional values, saw-tooth chip segmental degree and frequency. The results suggest that chip morphology transits from continuous to saw-tooth chip with increasing feed rate and cutting speed, and changing a tool’s positive rake angle to negative rake angle. There exists a critical cutting speed at which the chip morphology transfers from continuous to saw-tooth chip. The saw-tooth chip segmental frequency decreases as the feed rate and the tool negative rake angle value increases; however, it increases almost linearly with the cutting speed. The larger negative rake angle, the larger feed rate and higher cutting speed dominate saw-tooth chip morphology while positive rake angle, small feed rate and low cutting speed combine to determine continuous chip morphology. The 3-D FE model considers tool nose radii of 0.4 mm and 0.8 mm, respectively, with tool lead angels of 0 deg and 7 deg. The model successfully simulates 3-D saw-tooth chip morphology generated by periodic adiabatic shear and demonstrates the continuous and saw-tooth chip morphology, chip characteristic line and the material flow direction between chip-tool interfaces. The predicted chip morphology, cutting temperature, plastic strain distribution, and cutting forces agree well with the experimental data. The oblique cutting process simulation reveals that a bigger lead angle results in a severer chip deformation, the maximum temperature on the chip-tool interface reaches 1289 deg, close to the measured average temperature of 1100 deg; the predicted average tangential force is 150N, with 7% difference from the experimental data. When the cutting tool nose radius increases to 0.8 mm, the chip’s temperature and strain becomes relatively higher, and average tangential force increases 10N. This paper also discusses reasons for discrepancies between the experimental measured cutting force and that predicted by finite element simulation.


2020 ◽  
Vol 14 (3) ◽  
pp. 7141-7151 ◽  
Author(s):  
R. Omar ◽  
M. N. Abdul Rani ◽  
M. A. Yunus

Efficient and accurate finite element (FE) modelling of bolted joints is essential for increasing confidence in the investigation of structural vibrations. However, modelling of bolted joints for the investigation is often found to be very challenging. This paper proposes an appropriate FE representation of bolted joints for the prediction of the dynamic behaviour of a bolted joint structure. Two different FE models of the bolted joint structure with two different FE element connectors, which are CBEAM and CBUSH, representing the bolted joints are developed. Modal updating is used to correlate the two FE models with the experimental model. The dynamic behaviour of the two FE models is compared with experimental modal analysis to evaluate and determine the most appropriate FE model of the bolted joint structure. The comparison reveals that the CBUSH element connectors based FE model has a greater capability in representing the bolted joints with 86 percent accuracy and greater efficiency in updating the model parameters. The proposed modelling technique will be useful in the modelling of a complex structure with a large number of bolted joints.


2020 ◽  
Vol 2020 (10) ◽  
pp. 22-28
Author(s):  
Vadim Kuc ◽  
Dmitriy Gridin

The work purpose was the investigation of dependence impact of tool geometrical parameters upon shaping effort during internal groove cutting. As a realization for the fulfillment of the helical groove processing investigation there was used a software complex based on a finite element method and a computer mathematic system. As a result of the investigations carried out there was obtained a regression equation manifesting the dependence of factors impact upon axial force falling on one tooth of the tool in the set scale of factor parameters. The scientific novelty consists in that in the paper there is considered a new method for helical groove cutting in which a shaping motion is carried out at the expense of the contact interaction of a tool and a billet performing free cutting. The investigation results obtained allowed determining the number of teeth operating simultaneously, that can be used further at cutting mode setting, and also as recommendations during designing tool design.


2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110090
Author(s):  
Peiyu He ◽  
Qinrong Qian ◽  
Yun Wang ◽  
Hong Liu ◽  
Erkuo Guo ◽  
...  

Slewing bearings are widely used in industry to provide rotary support and carry heavy load. The load-carrying capacity is one of the most important features of a slewing bearing, and needs to be calculated cautiously. This paper investigates the effect of mesh size on the finite element (FE) analysis of the carrying capacity of slewing bearings. A local finite element contact model of the slewing bearing is firstly established, and verified using Hertz contact theory. The optimal mesh size of finite element model under specified loads is determined by analyzing the maximum contact stress and the contact area. The overall FE model of the slewing bearing is established and strain tests were performed to verify the FE results. The effect of mesh size on the carrying capacity of the slewing bearing is investigated by analyzing the maximum contact load, deformation, and load distribution. This study of finite element mesh size verification provides an important guidance for the accuracy and efficiency of carrying capacity of slewing bearings.


Author(s):  
Ashwini Gautam ◽  
Chris Fuller ◽  
James Carneal

This work presents an extensive analysis of the properties of distributed vibration absorbers (DVAs) and their effectiveness in controlling the sound radiation from the base structure. The DVA acts as a distributed mass absorber consisting of a thin metal sheet covering a layer of acoustic foam (porous media) that behaves like a distributed spring-mass-damper system. To assess the effectiveness of these DVAs in controlling the vibration of the base structures (plate) a detailed finite elements model has been developed for the DVA and base plate structure. The foam was modeled as a poroelastic media using 8 node hexahedral elements. The structural (plate) domain was modeled using 16 degree of freedom plate elements. Each of the finite element models have been validated by comparing the numerical results with the available analytical and experimental results. These component models were combined to model the DVA. Preliminary experiments conducted on the DVAs have shown an excellent agreement between the results obtained from the numerical model of the DVA and from the experiments. The component models and the DVA model were then combined into a larger FE model comprised of a base plate with the DVA treatment on its surface. The results from the simulation of this numerical model have shown that there has been a significant reduction in the vibration levels of the base plate due to DVA treatment on it. It has been shown from this work that the inclusion of the DVAs on the base plate reduces their vibration response and therefore the radiated noise. Moreover, the detailed development of the finite element model for the foam has provided us with the capability to analyze the physics behind the behavior of the distributed vibration absorbers (DVAs) and to develop more optimized designs for the same.


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