Modeling and Simulation of Airflow Omnibearing Posture Sensor

2014 ◽  
Vol 889-890 ◽  
pp. 817-820
Author(s):  
Qi Rui Yang ◽  
Lin Hua Piao ◽  
Wen Jie Tian

In order to improve the performance of sensor, Using ANSYS software, the three-dimensional finite element modelling method and simulation results of micromachined airflow omnibearing level posture sensor are presented. The results show that: (1)Using the sense organ’s symmetry characteristic, a half model is built first, which is convenient for modelling and observing the simulation results;(2) Gridding should be meshed more densely where fluid grads is large, which is helpful of saving simulation time and improving precision. Compared to two-dimensional modeling, the simulation results of three-dimensional modeling are more comprehensive and exact, which provides dependable basis for further research of the sensor.

Author(s):  
S. Khajehpour ◽  
R. G. Sauve´ ◽  
N. Badie

A method has been developed to incorporate the local three-dimensional shell behavior of two concentric tubes in the two-dimensional beam modeling of the problem. The two dimensional modeling of fuel channels in CANDU pressurized heavy water nuclear reactors is used in lieu of a more accurate three dimensional finite element approach in order to reduce the on-line simulation time which greatly affects the SLAR (Spacer Location And Repositioning) maintenance operation cost during outage. However, effort must be made to include the three-dimensional shell behavior of these channels into the two-dimensional modeling. In recent studies a nonlinear force-dependent model for contact stiffness between the calandria tube and pressure tube has been developed. However, local deformation of calandria the tube at spacer locations due to in-reactor creep leads to settling of the spacer into the calandria tube that consequently reduces the gap between the two tubes. In this work, the effect of local deformation (elastic and creep) of calandria tubes on modeling of contact at spacer locations is assessed using a three dimensional finite element code. The result is incorporated into a two-dimensional beam model of the problem as a reduction in size of the spacers that separate the two tubes. It is shown that the proposed method increases the accuracy of prediction of contact time and the spacer. In general, the method described in this paper suggests a way to incorporate local shell deformation into beam models of slender shell structure.


2007 ◽  
Vol 353-358 ◽  
pp. 1072-1077 ◽  
Author(s):  
Ren Ping Shao ◽  
Xin Na Huang ◽  
Pu Rong Jia ◽  
Wan Lin Guo ◽  
Kaoru Hirota

A method of damage detection and fault diagnosis for gears is presented based on the theory of elastomeric dynamics according to the theory of cracked beam. It takes an advantage of accurate fault diagnosis of gear body using the change of dynamic features and has some advantages for dynamic design of gear systems.The dynamics characteristics, i.e., natural frequency, vibration shape,dynamic response and so on, due to crack of gear tooth are studied, and the gear dynamics characteristics caused by the position and size of crack are deeply investigated by comparison with FEM. The theoretical analysis results are contrasted with numerical simulation results and shows good agreement with the result by FEM. The proposed method can be used to detect damage and diagnose fault for gear structures and also can be applied to designing dynamic characteristics for gear systems.


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