Multifidelity component interface reduction and modal truncation augmentation

The component mode synthesis based on the Craig-Bampton method has two strong limitations that appear when the number of the interface degrees of freedom is large. First, the reduced-order model obtained is overweighed by many unnecessary degrees of freedom. Second, the reduction step may become extremely time consuming. Several interface reduction techniques addressed successfully the former problem, while the latter remains open. In this paper we tackle this latter problem through a simple interface-reduction technique based on an a-priory choice of the interface modes. An efficient representation of the interface displacement field is achieved adopting a set of orthogonal basis functions determined by the interface geometry. The proposed method is compared with other existing interface reduction methods on a case study regarding a rotor blade of an axial compressor.

Download Full-text

A Metric for Modal Truncation in Model Reduction Problems Part 1: Performance and Error Analysis

Topics in Modal Analysis, Volume 7 - Conference Proceedings of the Society for Experimental Mechanics Series ◽

10.1007/978-1-4614-6585-0_73 ◽

2013 ◽

pp. 781-788 ◽

Cited By ~ 2

Author(s):

Sadegh Rahrovani ◽

Majid Khorsand Vakilzadeh ◽

Thomas Abrahamsson

Keyword(s):

Error Analysis ◽

Model Reduction ◽

Modal Truncation

Download Full-text

Automated Test System for Test and Evaluation of C-Band Transmitter Packages for Geosat Spacecrafts

International Journal of Recent Technology and Engineering - 2 ◽

10.35940/ijrte.b3350.078219 ◽

2019 ◽

Vol 8 (2) ◽

pp. 4591-4596

Keyword(s):

Rapid Development ◽

User Interaction ◽

Test System ◽

General Purpose ◽

Virtual Instrumentation ◽

Labview Software ◽

Test And Evaluation ◽

Automated Test System ◽

Automated Test ◽

Component Interface

The aim of this paper is to develop an Automated Test System (ATS) for the Test and Evaluation of C-Band Transmitter packages for GEOSAT Space crafts using Virtual Instrumentation. Efficiency, coverage, quality and accuracy for the test and evaluation of Device Under Test (DUT) can be increased by Automated Testing. Minimizing the errors anticipated with manual intervention. Automated Test System using Virtual instrumentation (VI) combines rapid development software and modular, flexible hardware to create user-defined test systems. Here Modular PXI (Peripheral component interface Extensions for Instrumentation) instruments from National Instruments are used with NI-LabVIEW software for realizing the ATS. For characterizing the C-Band Transmitter, Spectrum analyzer & Digital Multimeter (DMM) is configured in PXI form-factor and the Power supply is controlled through GPIB (General Purpose Interface Bus) bus. The complete software is developed using NI LabVIEW which takes care of configuring the test condition and analyzing the DUT performance. The user friendly GUI well takes care of user interaction to the ATS.

Download Full-text

The Elucidation of Mechanism of Local Sound Pressure Increase Phenomenon

Computer Technology and Applications ◽

10.1115/pvp2004-2764 ◽

2004 ◽

Cited By ~ 1

Author(s):

Reiko Koganei ◽

Shigemasa Ando ◽

Qinzhong Shi ◽

Ichiro Hagiwara

Keyword(s):

Structural Damage ◽

Sound Pressure ◽

Pressure Increase ◽

Narrow Gap ◽

Local Pressure ◽

Acoustic Environment ◽

Space Instruments ◽

Acoustic Cavity ◽

Lift Off ◽

Component Interface

Payloads of satellite are exposed on the severe acoustic environment at the process of lift-off and supersonic zone of a launcher. This acoustic environment excites the payload in high pressure and broad frequency band of random acoustical excitation, which may cause serious damage to the structures or instruments of the spacecraft inside. Space instruments are designed and verified to the acoustic environment by ground reverberant acoustic chamber in order to specify random vibration level at component interface and to verify the payloads are working in function and the structure does not have structural damage. The present load sound pressure specification assumes that the sound pressure interior fairing is uniformly distributed. In spacecraft system acoustic tests, local pressure increase occurs in the narrow gap between spacecraft primal structure and components facing toward the fairing wall. This acoustical environment load to the components differs from that the components were tested alone and the flight acoustic environment may not be actually simulated in the ground testing. It is important to clarify the mechanism of sound pressure increase in the narrow gap in order to predict the level of sound pressure increase. In this study, we focus to the investigation of the mechanism by basic experiment including acoustic testing and vibration modal survey. It is clarified that the main reason of the phenomenon is dominated by the acoustic cavity on the appropriate boundary condition rather than structure vibration. And more, we predict the frequency at which the sound pressure increase at the narrow gap and compare analysis results with experiment results by using Boundary Element Method (BEM).

Download Full-text