scholarly journals Modeling of the Evolution of the Microstructure and the Hardness Penetration Depth for a Hypoeutectoid Steel Processed by Grind-Hardening

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1182
Author(s):  
Yu Guo ◽  
Minghe Liu ◽  
Mingang Yin ◽  
Yutao Yan
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Cellular Automata ◽  
Penetration Depth ◽  
Hardened Layer ◽  
Grind Hardening ◽  
Study Results ◽  
1045 Steel ◽  
Hardness Penetration Depth ◽  
Element Method

Grind-hardening processing is an emerging approach that combines the grinding and surface quenching process. During the process, the hardened layer—mainly martensite—is produced on the surface of the workpiece to achieve the purpose of surface strengthening. Above all, the surface temperature field of the hypoeutectoid-1045 steel workpiece was determined by finite element method for fully revealing the formation mechanism of the hardened layer. Further, the cellular automata approach was applied to dynamically simulate the transformation of both austenitization and martensitization from the initial microstructure. The hardness penetration depth was also predicted. Finally, a grind-hardening experiment was conducted to assess the theoretical study. Results showed that a combination of the finite element method and the cellular automata approach can effectively simulate the microstructure transformation of hardened layer. The microstructure and the hardness penetration depth were affected by the maximum grinding temperature and the heating rate. Research on the influence of grinding parameters showed that the hardness penetration depth increased as the depth of the wheel cut and feeding speed increased. Experiments revealed that the difference between predicted value and experimental value of the hardness penetration depth varied between 2.83% and 7.31%, which confirmed the effectiveness of the predicted model.

scholarly journals Prediction of Viscoelastic Pavement Responses under Moving Load and Nonuniform Tire Contact Stresses Using 2.5-D Finite Element Method

2020 ◽  
Vol 2020 ◽  
pp. 1-16 ◽  
Author(s):  
Chaoyang Wu ◽  
Hao Wang ◽  
Jingnan Zhao ◽  
Xin Jiang ◽  
Qiu Yanjun ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Moving Load ◽  
Contact Stresses ◽  
Point Load ◽  
Dynamic Responses ◽  
Study Results ◽  
Tensile Strains ◽  
Strain Responses ◽  
Element Method

This study developed two-and-half dimensional (2.5-D) finite element method (FEM) to predict viscoelastic pavement responses under moving loads and nonuniform tire contact stresses. The accuracy of 2.5-D FEM was validated with two analytical solutions for elastic and viscoelastic conditions. Compared to three-dimensional (3-D) FEM, the computational efficiency of the 2.5-D method was greatly improved. The effects of loading pattern and speed on pavement surface deflection and strain responses were analyzed for asphalt pavements with four different asphalt layer thicknesses. The analyzed pavement responses included surface deflections, maximum tensile strains in the asphalt layer, and maximum compressive strains on top of subgrade. The loading patterns have influence on the mechanical responses. According to the equivalent rule, the point load, rectangle type, and sinusoid-shape contact stresses were studied. It was found that the point load caused much greater pavement responses than that of the area-based loading. When the tire loading was simplified as uniform contact stress in rectangular area, the maximum tensile strains in the asphalt layer varied with the width/length ratio of contact area. Additionally, it was shown that the dynamic responses of pavement structure induced by the sinusoid-shape contact stresses and realistic nonuniform stresses were quite similar to each other in all the cases. The pavement strain responses decreased as the speed increased due to viscoelastic behavior of asphalt layer. The study results indicate that asphalt pavement responses under moving load can be calculated using the proposed 2.5-D FEM in a fast manner for mechanistic-empirical pavement design and analysis.

Multiscale Model of Shape Rolling Taking into Account the Microstructure Evolution - Schedule Design by Finite Element Method

2013 ◽  
Vol 871 ◽  
pp. 263-268 ◽  
Author(s):  
Łukasz Łach ◽  
Dmytro Svyetlichnyy
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Cellular Automata ◽  
Microstructure Evolution ◽  
Fem Simulation ◽  
Multiscale Model ◽  
Fem Modeling ◽  
Shape Rolling ◽  
Strain And Strain Rate ◽  
Element Method

The material properties are strongly depended on the microstructure. Recently, for modeling and prediction of microstructure evolution during the forming processes a cellular automata method is used. Combination of several methods in multiscale model allows to extend the possibilities of each method and obtain more reliable results, which are close to the real conditions. The objective of this study is development of multiscale model of microstructure evolution during the shape rolling process and use it for simulation of rolling of 5 mm round bars. Model uses for calculations the finite element (FEM) and cellular automata (CA) methods. Modeling consists of three stages: design of the shape rolling schedule with the definition of shape and sizes of grooves (FEM simulation of each pass, starting from the last pass), FEM modeling of shape rolling in the proper sequence of the passes, modeling of microstructure evolution by frontal cellular automata (FCA). Stages (especially the last two) can be repeated several times to optimize the technology in view of final microstructure. The paper presents the first stage of modeling, which includes design and selection of grooves scheme with used the finite element method. The last six passes were modeled. The rolling scheme obtained from the modeling in the next stage is simulated by FEM to obtain thermomechanical parameters of the process. Then, temperature, strain and strain rate distributions in bar cross-sections, rolling time and inter-pass time will be used as input data for modeling by FCA.

scholarly journals Determining and Analysing Support Conditions at Variable Construction of Crankshafts

2018 ◽  
Vol 1 (1) ◽  
pp. 553-560 ◽  
Author(s):  
Krzysztof Nozdrzykowski ◽  
Zenon Grządziel ◽  
Jozef Harušinec
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Research Subject ◽  
Elastic Deformations ◽  
Study Results ◽  
Reaction Forces ◽  
Support Conditions ◽  
Angle Of Rotation ◽  
Element Method

Abstract The article presents study results of the influence of crankshaft construction changes on the choice of support conditions allowing to eliminate deflections and elastic deformations of crankshafts under their self-weight. For the purpose of this study we implemented a programme for strength calculations Nastran FX 2010 which enables modelling the research subject with a finite element method and counting the value if reaction forces ensuring zero value of deflections on main journals at a change in the crankshaft’s angle of rotation.

An Investigation of the Shell Nosing Process by the Finite-Element Method. Part 2: Nosing at Elevated Temperatures (Hot Nosing)

1982 ◽  
Vol 104 (3) ◽  
pp. 312-318 ◽  
Author(s):  
Ming-Ching Tang ◽  
Shiro Kobayashi
Keyword(s):  
Heat Transfer ◽  
Finite Element Method ◽  
Finite Element ◽  
Elevated Temperatures ◽  
Heat Transfer Analysis ◽  
Coupled Analysis ◽  
The Finite Element Method ◽  
Quadrilateral Elements ◽  
1045 Steel ◽  
Element Method

The metal-forming processes of shell nosing at elevated temperatures were analyzed by the finite-element method. The strain-rate effects on materials properties and the flow stress dependence on temperatures were included in the finite-element analysis. A thermodynamic theory of visco-plasticity based on rational mechanics was adapted to a rigid-plastic material idealization. An implicit scheme is used for the time integration of heat transfer equations, which is coupled to the plasticity equations. The nine-node quadrilateral elements with quadratic velocity distribution were used for the workpiece, and four-node quadrilateral elements were used for the die in the heat transfer analysis and temperature calculations. The coupled analysis of heat transfer and deformation was applied to the forming of AISI 1045 steel shells. Correlation between simulation and experimental results are good.

Modeling and Analyzing for Rotor System with Imbalance-Misalignment Coupling Faults Based on Nonlinear Finite Element Method

2013 ◽  
Vol 312 ◽  
pp. 292-295
Author(s):  
Fu Ze Xu ◽  
Xue Jun Li ◽  
Guang Bin Wang ◽  
Yi Lin He
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Rotor System ◽  
Nonlinear Finite Element ◽  
Rolling Element Bearing ◽  
Nonlinear Finite Element Method ◽  
Time Frequency ◽  
Coupling Faults ◽  
Study Results ◽  
Element Method

This thesis constructs the dynamical model of the imbalance-misalignment coupling faults and the finite element model of the rotor system which are supported by rolling element bearing. It analyses the impacts from the coupling faults to the system on the basis of nonlinear finite element method, dynamic theory and Newmark-beta numerical integration method. It also studies the influence of the unbalance, misalignment and coupling faults to the system by applying the dynamic response chart and time-frequency properties. The study shows that there exist unstable high and low harmonic components, the unbalanced signal overshadowed by misalignment. It also discovers that besides the working frequency, there also exist tow times frequency and other high doubling components on the response spectra with two times frequency for the most. All those study results provide some theoretical reference for the fault diagnosing of the rotor bearing system, the vibration control and the stability research.

Sign in / Sign up

Export Citation Format

Share Document