scholarly journals Simulation, Modeling and Experimental Research on the Thermal Effect of the Motion Error of Hydrostatic Guideways

Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1445
Author(s):  
Pengli Lei ◽  
Zhenzhong Wang ◽  
Chenchun Shi ◽  
Yunfeng Peng ◽  
Feng Lu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Thermal Effect ◽  
Degrees Of Freedom ◽  
Machining Accuracy ◽  
The Finite Element Method ◽  
Initial State ◽  
Motion Error ◽  
Kinematics Model ◽  
Element Method

Hydrostatic guideways are widely applied in ultra-precision machine tools, and motion errors undermine the machining accuracy. Among all the influence factors, the thermal effect distributes most to motion errors. Based on the kinematic theory and the finite element method, a 3-degrees-of-freedom quasi-static kinematics model for motion errors containing the thermal effect was established. In this model, the initial state of the closed rail as a “black box” is regarded, and a self-consistent setting method for the initial state of the guide rails is proposed. Experiments were carried out to verify the thermal motion errors simulated by the finite element method and our kinematics model. The deviation of the measured thermal vertical straightness error from the theoretical value is less than 1 μm, which ensured the effectiveness of the model we developed.

Research on Machining Accuracy in Milling Ti6Al4V Thin-Walled Component with Paraffin Reinforcement

2012 ◽  
Vol 268-270 ◽  
pp. 504-509
Author(s):  
Biao Gao ◽  
Jie Sun ◽  
Jian Feng Li
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Machining Accuracy ◽  
The Finite Element Method ◽  
Technical Problems ◽  
Low Stiffness ◽  
Thin Walled ◽  
Element Method

According to the technical problems such as low stiffness vibration and dimension error in milling Ti6Al4V thin-walled component, the manufacturing with paraffin reinforcement is studied. Firstly, paraffin formula for milling thin-walled component is researched. Secondly, applying the finite element method (FEM) to predict the deformation of machining with paraffin reinforcement and the corresponding milling experiments is done to check the the validity of the model. Finally, the influences of machining accuracy about different paraffin formulas for the same component are obtained. This study supplies support for the research of paraffin formula which are based on reducing the distortion of workpiece.

Optimization Research on Workpiece Clamping Deformation Using Genetic Algorithm and Finite Element Method

2011 ◽  
Vol 189-193 ◽  
pp. 2153-2160
Author(s):  
Yu Wen Sun ◽  
Chuan Tai Zhang ◽  
Qiang Guo
Keyword(s):  
Genetic Algorithm ◽  
Finite Element Method ◽  
Finite Element ◽  
Machining Accuracy ◽  
Clamping Force ◽  
The Finite Element Method ◽  
Linear Programming Method ◽  
Fixture Layout ◽  
The Stability ◽  
Element Method

Optimal fixture involves fixture layout and clamping force determination. It is critical to ensure the machining accuracy of workpiece. In this paper, the clamping process is analyzed with the consideration of cutting forces and frictions using the finite element method. Then the fixture layout and clamping force are optimized by minimizing the workpiece deformation via a Genetic Algorithm (GA). Subsequently, linear programming method is used to estimate the stability of workpiece. It is shown through an example that the proposed method is proved to be efficient. The optimization result is not only far superior to the experiential one, but also the total optimization time can be reduced significantly.

COMPUTATIONAL CONTACT MECHANICS BASED ON THE rp-VERSION OF THE FINITE ELEMENT METHOD

2011 ◽  
Vol 08 (03) ◽  
pp. 493-512 ◽  
Author(s):  
DAVID FRANKE ◽  
ERNST RANK ◽  
ALEXANDER DÜSTER
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Degrees Of Freedom ◽  
The Finite Element Method ◽  
Problem Size ◽  
Element Mesh ◽  
Polynomial Degree ◽  
Adaptive Discretization ◽  
Loss Of Regularity ◽  
Element Method

In this paper we present an rp-adaptive discretization strategy to perform unilateral two-dimensional (2D) mechanical contact simulations by combining the r- and p-versions of the finite element method (FEM). The p-version leaves the finite element mesh unchanged and increases the shape function's polynomial degree in order to obtain convergence toward the exact solution of the underlying mathematical model. The r-method relocates nodes of an existing FE-mesh to improve the discretization of a given problem without introducing additional degrees of freedom, therefore, keeping the problem size fixed. The rp-version, which is a combination of the two aforementioned methods, is used in our study to move a node of the FE-mesh to the end of the contact zone to account for the loss of regularity that arises due to the change from contact to noncontact along the edge. It will be shown that highly accurate results can be obtained by using high-order (p) finite elements in combination with the penalty method and a relocation (r) of element nodes.

Dynamic Analysis of Cold-Rolling Process Using the Finite-Element Method

2015 ◽  
Vol 138 (4) ◽  
Author(s):  
Sajan Kapil ◽  
Peter Eberhard ◽  
Santosha K. Dwivedy
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Governing Equation ◽  
Degrees Of Freedom ◽  
Vertical Displacement ◽  
Work Roll ◽  
Equation Of Motion ◽  
Element Formulation ◽  
The Finite Element Method ◽  
Element Method

In this work, the finite-element method (FEM) is used to develop the governing equation of motion of the working roll of a four-high rolling mill and to study its vibration due to different process parameters. The working roll is modeled as an Euler Bernoulli beam by taking beam elements with vertical displacement and slope as the nodal degrees-of-freedom in the finite-element formulation. The bearings at the ends of the working rolls are modeled using spring elements. To calculate the forces acting on the working roll, the interaction between the working roll and the backup roll is modeled by using the work roll submodel, and the interaction between the working roll and the sheet is modeled by using the roll bite submodel (Lin et al., 2003, “On Characteristics and Mechanism of Rolling Instability and Chatter,” ASME J. Manuf. Sci. Eng., 125(4), pp. 778–786). Nodal displacements and velocities are obtained by using the Newmark Beta method after solving the governing equation of motion of the working roll. The transient and steady-state variation of roll gap, exit thickness profile, exit stress, and sheet force along the length of the strip have been found for different bearing stiffnesses and widths of the strip. By using this model, one can predict the shape of the outcoming strip profile and exit stress variation which will be useful to avoid many defects, such as edge buckling or center buckling in rolling processes.

An integrated finite element method, response surface methodology, and evolutionary techniques for modeling and optimization of machining fixture layout for 3D hollow workpiece geometry

2016 ◽  
Vol 231 (23) ◽  
pp. 4344-4359 ◽  
Author(s):  
KA Sundararaman ◽  
KP Padmanaban ◽  
M Sabareeswaran ◽  
S Guharaja
Keyword(s):  
Genetic Algorithm ◽  
Finite Element Method ◽  
Finite Element ◽  
Response Surface Methodology ◽  
Response Surface ◽  
Quadratic Model ◽  
Machining Accuracy ◽  
The Finite Element Method ◽  
Fixture Layout ◽  
Element Method

Machining fixtures play inevitable role in manufacturing to ensure the machining accuracy and workpiece quality. The layout of fixture elements, clamping forces, and machining forces significantly affect the workpiece elastic deformation during machining. The clamping and machining forces are necessary to immobilize and machine the workpiece, respectively. Finding the appropriate layout of fixture elements is the other possible way to reduce the workpiece deformation, which in turn improves the machining accuracy. The finite element method interfaced with evolutionary techniques is normally used for fixture layout optimization. In the finite element method, the workpiece is discretized into a number of small elements and fixture elements are placed only on the nodes. Hence, evolutionary techniques are capable of searching the optimal fixture layout from those discrete nodal points than from the entire area on the locating and clamping face. To overcome these limitations, in this research paper, response surface methodology is employed to establish a quadratic model between the position of fixture elements and maximum workpiece deformation. This enables the optimization techniques to search for the optimal solution in the continuous domain of the solution space. Then, the real-coded genetic algorithm based discrete optimization, continuous optimization based on binary-coded genetic algorithm and particle swarm optimization are employed to optimize the developed quadratic model and their performances are compared. The result clearly shows that the integration of finite element method, response surface methodology with particle swarm optimization is better than the integration with genetic algorithm to optimize the machining fixture layout and also reduces the computational complexity and time to a greater extent.

Simulation of tuning graphene plasmonic behaviors by ferroelectric domains for self-driven infrared photodetector applications

Nanoscale ◽  
2019 ◽  
Vol 11 (43) ◽  
pp. 20868-20875 ◽  
Author(s):  
Junxiong Guo ◽  
Yu Liu ◽  
Yuan Lin ◽  
Yu Tian ◽  
Jinxing Zhang ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Interfacial Effect ◽  
Infrared Photodetector ◽  
The Finite Element Method ◽  
Ferroelectric Domains ◽  
Element Method

We propose a graphene plasmonic infrared photodetector tuned by ferroelectric domains and investigate the interfacial effect using the finite element method.

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