Design of a Parametrically Excited Tuning Fork Microgyroscope

Author(s):  
Yongsik Lee ◽  
Z. C. Feng

Parametrically excited tuning fork micro gyroscopes have several attractive features. Most of all, the excitation may be externalized, which could simplify the design and fabrication of micro gyroscopes. However, there are no readily applicable tools to guide the design of these gyroscopes since the gyro structures are more complex than those structures whose responses to parametric excitations are known and since finite element analysis tools are not capable of studying parametric excitations. In this work, we adopt a novel approach to obtain a simplified model of the parametrically excited structure. Parameters in the simplified model are obtained using dynamic analysis capability of typical finite element programs and static nonlinear analysis capabilities.

Author(s):  
Robert X. Wang ◽  
Graham M. Chapman

Abstract This paper reports on the application of Electronic Speckle Pattern Interferometry (ESPI) technique in vibration measurement of turbine blading. Using the time-averaged mode of ESPI, the first six modes of a turbocharger blade with airfoil profile were identified. The effect of the complicated profile of the blade was established by studying simplified model blades. Coupled modes were identified and successfully separated. Experimental results are compared with those obtained using finite element analysis.


Author(s):  
Ane de Boer ◽  
Max A. N. Hendriks ◽  
Eva O. L. Lantsoght

<p>The Dutch Ministry of Infrastructure and the Environment is concerned with the safety of existing infrastructure and expected re-analysis of a large number of bridges and viaducts. Nonlinear finite element analysis can provide a tool to assess safety; a more realistic estimation of the existing safety can be obtained.</p><p>Dutch Guidelines, based on scientific research, general consensus among peers, and a long-term experience with nonlinear analysis, allow for a reduction of model and user factors and improve the robustness of nonlinear finite element analyses.</p><p>The 2017 version of the guidelines can be used for the finite element analysis of basic concrete structural elements like beams, girders and slabs, reinforced or prestressed. Existing structures, like box-girder structures, culverts and bridge decks with prestressed girders in composite structures can be analysed.</p><p>The guidelines have been developed with a two-fold purpose. First, to advice analysts on nonlinear finite element analysis of reinforced and pre-stressed concrete structures. Second, to explain the choices made and to educate analysts, related to the responsibility of limiting model uncertainty.</p><p>This paper contains an overview of the latest version of the guideline and its latest validation extensions. Most important impact is the extended operational lifetime of an existing reinforced concrete slab structure.</p>


1978 ◽  
Vol 13 (3) ◽  
pp. 141-147 ◽  
Author(s):  
R Bell ◽  
P P Benham

Brittle-lacquer and strain-gauge methods and a finite-element analysis are used to determine stress distributions in a simplified model and an actual centrifugal fan impeller.


2014 ◽  
Vol 852 ◽  
pp. 447-451
Author(s):  
Yan Fang Yue ◽  
Zhi Bo Xin ◽  
Jin Ye Wang

The finite element method was applied in the construction design of the welding column of CNC boring machine for dynamic analysis and modal analysis. The laws of deformation and stress of a loaded column were obtained, and the natural frequency of each step and modes of column were also given according to this method. The results implied that the strength and the stiffness of welding column were met the machining requirements. Machine working frequency far less than inherent frequency, thus resonance is not easy to occur. Through the way, the optimization proposals of structure were given.


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