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Theoretic analysis and experiment on aeroelasticity of very flexible wing

Science China(Technological Sciences) 2012年第9期55卷 2489-2500页

作者： XIE ChangChuan LIU Yi YANG Chao Beijing University of Aeronautics and Astronautics Beijing 100190China

A high-altitude long-endurance aircraft with high-aspect-ratio wing usually generates large deformation,which brings the geometric nonlinear aeroelastic *** recent decades,it has become a key focus of the international researchers of *** some critical technologies are not developed systematically,such as aerodynamic calculation methods of the curved wing with deformation,moreover,there are few experimental validations of these *** this paper,we established the steady aerodynamic calculating method of the curved wing with quite large deformation based on the extended lifting line method,and calculated the unsteady aerodynamics using the strip theory considering curved surface *** the structure geometrical nonlinear finite element method,we constructed a systematic analytic approach for the static aeroelasticity and flutter of very flexible wing,and further designed the ground vibration and wind tunnel test to verify this *** the test and the theoretic results comparison,we concluded that the extended lifting line method has adaptable precision for the static aeroealsticity and the strip theory considering curved surface effects for flutter analysis can give exact critical speed and flutter mode when the dynamic stall does not *** work in this paper shows that the geometric nonlinear aeroelastic analytic approach for very flexible wing has very high efficiency and adaptable *** can be used in the engineering applications,especially the iterated design in preliminary stage.

关键词： geometry nonlinear aerodynamic aeroelastic modal testing wind tunnel test

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modal Strain Energy Based Structural Damage Localization for Offshore Platform using Simulated and Measured Data

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Journal of Ocean University of China 2014年第3期13卷 397-406页

作者： WANG Shuqing LIU Fushun ZHANG Min College of Engineering Ocean University of China

modal strain energy based methods for damage detection have received much attention. However, most of published articles use numerical methods and some studies conduct modal tests with simple 1D or 2D structures to verify the damage detection algorithms. Only a few studies utilize modal testing data from 3D frame structures. Few studies conduct performance comparisons between two different modal strain energy based methods. The objective of this paper is to investigate and compare the effectiveness of a traditional modal strain energy method(Stubbs index) and a recently developed modal strain energy decomposition(MSED) method for damage localization, for such a purpose both simulated and measured data from an offshore platform model being used. Particularly, the mode shapes used in the damage localization are identified and synthesized from only two measurements of one damage scenario because of the limited number of sensors. The two methods were first briefly reviewed. Next, using a 3D offshore platform model, the damage detection algorithms were implemented with different levels of damage severities for both single damage and multiple damage cases. Finally, a physical model of an offshore steel platform was constructed for modal testing and for validating the applicability. Results indicate that the MSED method outperforms the Stubbs index method for structural damage detection.

关键词： offshore platform damage localization strain energy mode shapes modal testing

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Modeling and Measurement of a Tunable Acoustoelastic System

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Sound & Vibration 2018年第3期52卷 12-17页

作者： Deborah Fowler Garrett Lopp Dhiraj Bansal Ryan Schultz Matthew Brake Micah Shepherd Undergraduate Student University of MassachusettsLowell01854 Graduate Research Assistant University of Central FloridaOrlandoFL32816 Graduate Student University of Colorado BoulderBoulderCO 80309 Sandia National Laboratories PO Box 5800-MS0557AlbuquerqueNM87123 Assistant Professor William Marsh Rice University6100 Main StMS 321HoustonTX 77005 Assistant Research Professor The Pennsylvania State UniversityPO Box 30State CollegePA 16804

Acoustoelastic coupling occurs when a hollow structure’s in-vacuo mode aligns with an acoustic mode of the internal *** impact of this coupling on the total dynamic response of the structure can be quite severe depending on the similarity of the modal frequencies and ***,acoustoelastic coupling is not a design feature,but rather an unintended result that must be remedied as modal tests of structures are often used to correlate or validate finite element models of the uncoupled ***,however,a test structure is intentionally designed such that multiple structural and acoustic modes are well-aligned,resulting in a coupled system that allows for an experimental ***,coupling in the system is identified using a measure termed the magnification ***,the structural-acoustic interaction is *** to the system demonstrate the dependency of the coupling on changes in the mode shape and frequency *** includes an investigation of several practical techniques used to decouple the system by altering the internal acoustic cavity,as well as the structure *** results show that acoustic absorption material effectively decoupled the structure while structural modifications,in their current form,proved *** available acoustic absorptive material was effective in reducing the coupled effects while presumably adding negligible mass or stiffness to the structure.

关键词： Structural-acoustic interaction coupled modes acoustic absorption acoustic modes modal testing

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Engineering Studies on a CFRP Structure for a High-Energy Physics Experiment

Engineering Studies on a CFRP Structure for a High-Energy Ph...

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第十三届国际复合材料会议

作者： R.Ribeiro S.daMotaSilva J.DiasRodrigues M.Vaz P.Reis CERN-European Laboratory for Particle Physics Geneva 23 CH-1211 Switzerland CERN-European Laboratory for Particle Physics Geneva 23 CH-1211 Switzerland Faculdade de Engenharia da Universidade do Porto Rua dos Bragas 4099 Porto Portugal Faculdade de Engenharia da Universidade do Porto Rua dos Bragas 4099 Porto Portugal Faculdade de Engenharia da Universidade do Porto Rua dos Bragas 4099 Porto Portugal CERN-European Laboratory for Particle Physics Geneva 23 CH-1211 Switzerl

＜正＞The performance of the future high-energy physics experiments depends on the stability and design of the supporting structures of the particle’s detection elements. These structures, typically with several meters long, must be light, highly stable, stiff and radiation tolerant in an environment where external vibrations, high radiation levels, material ageing, temperature and humidity gradients are not negligible [1]. These requirements generally orient the materials choice towards Carbon Fibre Reinforced Plastics （CFRP） with highly performing fibres and resins qualified for aerospace applications. The engineering design of these structures comprises a careful development of finite element models and further validation by prototype testing.

关键词： modal testing CFRP lightweight structures high-energy physics experiment

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Practice on Gravity-1 Rocket Dynamic Characteristics Design

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Aerospace China 2024年第1期25卷 9-17页

作者： BU Xiangwei SONG Yinghui HUANG Shuai Orienspace Technology(Shandong)Co. LtdBeijing 100076

Since the Dongfeng-2 missile, full-vehicle modal testing has been established as an indispensable part of the development and testing of rocket and missile models. However, as rockets have been developed larger, the cost and duration of such tests have significantly increased, magnifying their impact on model development. This article follows the process of the modal testing practice of the Gravity-1 rocket, reviewing and summarizing the design process of the rocket's dynamic characteristics. Initially, the article introduces common modeling techniques for launch rockets, including the mass-beam model and the hybrid element model. It then discusses the relationship between the structural dynamics model of the launch rocket and modal testing, aiming to reduce testing costs through refined structural dynamics modeling methods. Subsequently, the article describes the dynamic characteristics design process of the Gravity-1 carrier rocket, categorizes structural parameters, and studies how the selection of structural parameters affects the predicted dynamic characteristics of the rocket. Finally, it elaborates on the design of the modal testing scheme and the dynamic characteristics design based on the test data.

关键词： Gravity-1 dynamic characteristics modal testing structural dynamics model

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