Modeling the Response of Surface Micromachined Thermal Actuators

Author(s):  
Amarendra P. Atre

Thermal microactuators, devices that use the principle of thermal expansion to amplify motion, have several advantages in comparison with other actuators used to motivate surface micromachined components such as rotary microengines. They provide higher output forces and have simple geometries. Accurate steady-state and transient modeling of such thermal actuators provides a tool for design optimization to obtain better actuator performance. This paper describes the development, modeling issues and results of a three dimensional multiphysics non-linear finite element model of a surface micromachined thermal actuator. The simulation results are compared with experimentally measured data. Reasonable agreement is observed for static actuator deflection response. The measured transient response is observed to be significantly slower than that predicted by the finite element model.

1999 ◽  
Vol 122 (3) ◽  
pp. 569-575 ◽  
Author(s):  
Alejandro Felix ◽  
Shreyes N. Melkote ◽  
Yoichi Matsumoto

This paper addresses the modeling and prediction of the normal holding force in an electromagnetic chuck used in precision machining applications. Knowledge of the normal holding force is necessary to determine if a given chuck is capable of preventing workpiece slip during machining. First, an analytic model termed the magnetic circuit model was developed and compared with experimental holding force data. It was found that this model, although simple in form, was limited in its ability to accurately predict the holding force over the entire range of conditions investigated. The discrepancies in the model were attributed to its inability to accurately model the leakage flux and nonuniform distribution of the magnetic flux. A three-dimensional finite element model was then developed to overcome these limitations. Predictions with this model were found to be in better agreement with experiments, yielding prediction errors within 25 percent in most cases. The finite element model also provided an explanation for the observed decrease in the measured holding force at current values beyond a certain threshold. [S1087-1357(00)01503-3]


2011 ◽  
Vol 317-319 ◽  
pp. 2373-2377
Author(s):  
Guo Juan Shang ◽  
Gen Li Shan ◽  
Xi Juan Qi

Based on sufficient market research, a new model of self-unloading semi-trailer, whose maximum loading capacity is 30 tons, has been designed. The paper describes its overall structure, the three-dimensional diorama model and the finite element model of the frame. Based on the analysis of the models and the results of the calculation, the parameters of the frame are optimized. The advantages of the new design are as follows: the new design makes the most of the advantages of self-unloading trailers and semi-trailers, that is, self-unloading, security, stability, high efficiency, environmental protection.


2011 ◽  
Vol 101-102 ◽  
pp. 1002-1005 ◽  
Author(s):  
Jing Zhao ◽  
Li Qun Lu

The process of multi-wedge cross wedge rolling is an advanced precision technology for forming long shaft parts such as automobile semi-axes. Three-dimensional solid model and the finite element model of semi-axes on automobile and dies of its cross wedge rolling were established. The process of cross wedge rolling was simulated according to the actual dimension of semi-axes on automobile utilizing the finite element method (FEM)software ANSYS/LS-DYNA. The required force parameters for designing semi-axes mill are determined. The appropriate roller width was determined according to the length and diameter of semi-axes on automobile. The results have provided the basis for the design of specific structure of automobile semi-axes cross wedge rolling mill.


2019 ◽  
Vol 5 (4) ◽  
pp. 121
Author(s):  
Aykut Uray ◽  
Hasan Selim Şengel ◽  
Serdar Çarbaş

In this study, non-destructive tests and laboratory tests were carried out in order to determine the material properties in Iznik Yeşil Mosque, Iznik District, Bursa Province. For the purpose of determining the soil characteristics of the building, the soil survey studies conducted in the Iznik Yeşil Mosque area were investigated. The finite element model was formed by making a three dimensional model study of the structure. With the finite element model, static analysis, modal analysis and behavioral spectrum analysis were performed under vertical loads in order to collect data for the damaged areas of the structure.


2011 ◽  
Vol 199-200 ◽  
pp. 1273-1280
Author(s):  
Hong Wei Guo ◽  
Rong Qiang Liu ◽  
Zong Quan Deng

The dynamic equivalent continuum model of beamlike space deployable lattice truss which is repetition of the basic truss bay is established based on the energy equivalence. The finite element model of the lattice truss is also developed. Free vibration frequencies and mode shapes are calculated and simulated based on equivalent continuum model and discrete finite element model. The analytical solutions calculated by equivalent continuum model match well with the finite element model simulation results. A prototype of deployable lattice truss consist of 20 truss bays is manufactured. The dynamic response of lattice truss with different truss bays are tested by dynamic vibration experiment, and natural frequencies of lattice truss with different length are obtained from acceleration response curves. The experiment results are compared with simulation results which verifies that the correctness of finite element model, which also validate the effectiveness of equivalent continuum model indirectly.


1993 ◽  
Vol 17 (2) ◽  
pp. 257-269 ◽  
Author(s):  
R.L. Kushwaha

A non-linear finite element model was developed for three dimensional soil cutting by tillage tools. A hyperbolic constitutive relation for soil was used in the model. Analysis was carried out to simulate soil cutting with rectangular flat and triangular tillage blades at different rake angles and with curved blades. Interface elements were used to model the adhesion and the friction between soil and blade surface. Soil forces obtained from the finite element model for the straight blades were verified with the results from laboratory tillage tests in the soil bin. The finite element model predicted draft force accurately for both tillage tools. Results indicated that the draft was a function of rake angle, tool shape and the curvature.


Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2121
Author(s):  
Jianpeng Wu ◽  
Liyong Wang ◽  
Le Li ◽  
Yuechao Shu ◽  
Li Yang ◽  
...  

Local high temperature, stress concentration, and abnormal friction coefficients will appear at the friction pair in a wet clutch as a result of surface topography real-time changing. In order to improve the reliability of clutch friction components and reduce the failure phenomenon, the three-dimensional fractal surface topography data of the actual rough surface asperities are scanned, extracted, and processed successively, and then the finite element model of the rotary sliding friction pair is established considering the micro surface topography. Based on the finite element model, the variation of surface stress and strain is analyzed, and the friction coefficient measured experimentally is taken as the model input. It is concluded that when the rough surface and smooth surface make contact with each other, the maximum stress and plastic strain appear at the inner radius edge. Therefore, this research has a guiding significance for the structural design and processing technology of the friction components in a vehicle clutch.


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