Structural dynamic response analysis due to the slit flow between the tailplane and the elevator

2021 ◽  
pp. 095441002110169
Author(s):  
Ju Qiu ◽  
Jiali Tang ◽  
Chundu Sun ◽  
Fengyu Dai
Keyword(s):  
Flow Field ◽  
Vibration Analysis ◽  
Vibrational Frequency ◽  
Dynamic Loads ◽  
Structural Vibration ◽  
Response Analysis ◽  
Vibrational Motion ◽  
Structural Failure ◽  
Structural Dynamic ◽  
Slit Flow

Any aircraft in flight is subjected to dynamic loads. Following vibration-related accidents, a flow field and vibration analysis can be carried out to analyze the data and study the cause of the accident. When slit airflow enters the cavity between the tailplane structure and the elevator, a mixed vortex is formed. If the vortex-induced vibrational frequency of around 50 Hz happens to be close to the natural frequency of the structure at 46 Hz, it is likely to induce structural vibration (resonance). The resonance can cause excessive fatigue damage which can ultimately lead to structural failure and the loss of the component or the aircraft. Damping methods can be employed to control vibration within the structure by reducing the amplitude of that vibrational motion by 83%. This article details a recreation of one example of structural vibration within an airborne aircraft.

Dynamic Response of a Steel-Concrete Hybrid Frame to Support 15MW Compressor

2012 ◽  
Author(s):  
Seunghoon Shin ◽  
Guangyoung Sun ◽  
Juwon Lee ◽  
Kangboo Kim
Keyword(s):  
Dynamic Analysis ◽  
Structural Dynamics ◽  
Structural Design ◽  
Modal Testing ◽  
Dynamic Loads ◽  
Structural Vibration ◽  
Aerodynamic Load ◽  
Radial Load ◽  
Structural Dynamic ◽  
Test Result

In this paper, the structural dynamics study of the frame to support 15MW compressor is suggested. This study used the steel-concrete hybrid frame to support a large compressor system. This paper provided experimental and analytical method to structural design the hybrid frame by considering in rotordynamics and aerodynamics. Dynamic characteristics of the frame have to be identified to tune the finite element model’s boundary condition and to avoid resonance. Therefore modal testing of the frame is performed and boundary conditions are modified applying to the previously obtained modal parameters. While compressor is operated, multiple dynamic loads of compressor, motor and expander may excite on the frame. The total dynamic load is derived by axial aerodynamic load of impeller, radial load of gear and unbalance load of rotor. After dynamic analysis completion, the analysis result is compared with test result to verify the accuracy of analysis. Through this structural dynamic analysis, structural vibration response of hybrid frame can be estimated.

Structural Dynamic Analysis Approach Used in a GE Heavy Duty Gas Turbine Combustor for MTBM Enhancement

2013 ◽  
Author(s):  
Bihari lal Jangid ◽  
Michele Provenzale ◽  
Eugenio Del Puglia
Keyword(s):  
Gas Turbine ◽  
Life Prediction ◽  
Failure Modes ◽  
Dynamic Models ◽  
Structural Vibration ◽  
Response Analysis ◽  
Structural Dynamic ◽  
Combustion Dynamics ◽  
Rotor Imbalance ◽  
Heavy Duty Gas Turbine

Gas turbine combustors are subjected to vibrations due to combustion dynamics pressure and rotor imbalance force which results in forced excitation of hardware. Such structural vibration leads to high cycle fatigue and wear out of contact interfaces of combustor, thus limiting hardware durability with reduced maintenance intervals. To have more realistic hardware life prediction for both failure modes, it is vital to understand structural dynamic behavior of combustor assembly in the presence of vibratory loads. This paper describes the methodology used in developing MS5002D LHE combustor assembly linearized finite element dynamic models, the strategy to calibrate them with experimental data and the approach used to perform a forced responded analysis with harmonically varying combustion dynamics pressure and rotor imbalance force. Study shows that with adopted approach, an acceptable modal correlation between the model and the experimental test rig can be achieved. The forced dynamic response analysis results, in terms of dynamic stress distribution, interface sliding displacements and contact loads, represent the needed inputs for life prediction and for addressing the design improvements.

scholarly journals Analytical corrections for double-cantilever beam tests

2021 ◽  
Author(s):  
T. Chen ◽  
C. M. Harvey ◽  
S. Wang ◽  
V. V. Silberschmidt
Keyword(s):  
Elastic Foundation ◽  
Analytical Solutions ◽  
Data Reduction ◽  
Crack Tip ◽  
Beam Theory ◽  
Dynamic Loads ◽  
Structural Vibration ◽  
Mode I ◽  
Mode I Fracture ◽  
Reduction Methods

AbstractDouble-cantilever beams (DCBs) are widely used to study mode-I fracture behavior and to measure mode-I fracture toughness under quasi-static loads. Recently, the authors have developed analytical solutions for DCBs under dynamic loads with consideration of structural vibration and wave propagation. There are two methods of beam-theory-based data reduction to determine the energy release rate: (i) using an effective built-in boundary condition at the crack tip, and (ii) employing an elastic foundation to model the uncracked interface of the DCB. In this letter, analytical corrections for a crack-tip rotation of DCBs under quasi-static and dynamic loads are presented, afforded by combining both these data-reduction methods and the authors’ recent analytical solutions for each. Convenient and easy-to-use analytical corrections for DCB tests are obtained, which avoid the complexity and difficulty of the elastic foundation approach, and the need for multiple experimental measurements of DCB compliance and crack length. The corrections are, to the best of the authors’ knowledge, completely new. Verification cases based on numerical simulation are presented to demonstrate the utility of the corrections.

Vibration behavior of an overhead conductor under updraft winds

2021 ◽  
pp. 107754632110058
Author(s):  
Qi Zhou ◽  
Liangtao Zhao ◽  
Chong Zheng ◽  
Feng Tu
Keyword(s):  
Induced Response ◽  
Response Analysis ◽  
Response Factor ◽  
Structural Dynamic ◽  
Resonance Response ◽  
Structural Dynamic Characteristics ◽  
Strong Winds ◽  
American Society ◽  
Gust Response Factor ◽  
Gust Response

At present, the wind-induced response analysis of an overhead conductor is mainly based on the action of horizontal normal wind. However, for crossing hillsides or extremely strong winds, such a conductor will bear the action of updraft wind, which will change the geometry of the conductor and make its structural dynamic characteristics nonlinear to some extent. In this work, the in-plane and out-of-plane two-dimensional nonlinear equations were established under the action of self-weight and updraft wind. Furthermore, the improved equations of conductor tension and sag were obtained, and the wind-induced vibration response was further investigated. The results showed that the updraft wind caused the nonlinearity of the tension and sag of the overhead conductor, and the nonlinear geometric change significantly affected its resonance response, which exceeded 25% if the wind speed was 50 m/s. In addition, because the proportion of the resonance response in the total wind-induced response was different, the influence of the wind attack angle calculated using the gust response factor method on the gust response factor was slightly larger than that calculated using the the American society of civil engineers method.

SIMP for Complex Structures

2016 ◽  
Vol 846 ◽  
pp. 535-540
Author(s):  
David J. Munk ◽  
David W. Boyd ◽  
Gareth A. Vio
Keyword(s):  
Natural Frequencies ◽  
Dynamic Loads ◽  
Topology Optimisation ◽  
Complex Structures ◽  
Structural Failure ◽  
Frequency Range ◽  
Aerodynamic Loading ◽  
Frequency Excitation ◽  
Wing Structure ◽  
Lifting Surfaces

Designing structures with frequency constraints is an important task in aerospace engineering. Aerodynamic loading, gust loading, and engine vibrations all impart dynamic loads upon an airframe. To avoid structural resonance and excessive vibration, the natural frequencies of the structure must be shifted away from the frequency range of any dynamic loads. Care must also be taken to ensure that the modal frequencies of a structure do not coalesce, which can lead to dramatic structural failure. So far in industry, no aircraft lifting surfaces are designed from the ground up with frequency optimisation as the primary goal. This paper will explore computational methods for achieving this task.This paper will present a topology optimisation algorithm employing the Solid Isotropic Microstructure with Penalisation (SIMP) method for the design of an optimal aircraft wing structure for rejection of frequency excitation.

Regeneration-Induced Forced Response in Axial Turbines

2013 ◽  
Author(s):  
Jens Aschenbruck ◽  
Christopher E. Meinzer ◽  
Linus Pohle ◽  
Lars Panning-von Scheidt ◽  
Joerg R. Seume
Keyword(s):  
Turbine Blades ◽  
Forced Response ◽  
Response Analysis ◽  
Geometrical Parameters ◽  
Turbine Stage ◽  
Structural Dynamic ◽  
Air Turbine ◽  
Axial Turbines ◽  
Interaction Approach ◽  
Stagger Angle

The regeneration of highly loaded turbine blades causes small variations of their geometrical parameters. To determine the influence of such regeneration-induced variances of turbine blades on the nozzle excitation, an existing air turbine is extended by a newly designed stage. The aerodynamic and the structural dynamic behavior of the new turbine stage are analyzed. The calculated eigenfrequencies are verified by an experimental modal analysis and are found to be in good agreement. Typical geometric variances of overhauled turbine blades are then applied to stator vanes of the newly designed turbine stage. A forced response analysis of these vanes is conducted using a uni-directional fluid-structure interaction approach. The effects of geometric variances on the forced response of the rotor blade are evaluated. It is shown that the vibration amplitudes of the response are significantly higher for some modes due to the additional wake excitation that is introduced by the geometrical variances e.g. 56 times higher for typical MRO-induced variations in stagger-angle.

A Time-Domain DQ Approach for Vibration Analysis of Beams

2013 ◽  
Vol 631-632 ◽  
pp. 957-961
Author(s):  
Jian She Peng ◽  
Gang Xie ◽  
Liu Yang ◽  
Yu Quan Yuan
Keyword(s):  
Time Domain ◽  
Vibration Analysis ◽  
Differential Quadrature Method ◽  
Boundary Value ◽  
Linear Equations ◽  
Initial Boundary ◽  
Differential Quadrature ◽  
Structural Vibration ◽  
Quadrature Method ◽  
Initial Boundary Value

This paper presents a new time-domain DQ (differential quadrature) method for structural vibration analysis. It adopts differential quadrature method both in space domain and in time domain on the basis of governing partial differential equation and initial-boundary value condition of vibration problems of structures, and gets new differential quadrature linear equations with complete initial-boundary value conditions for solving all parameters of the displacement-field. The examples in this paper show the time-domain differential quadrature method is a useful and efficient tool for structural vibration analysis.

scholarly journals Vibration Analysis of Kenyir Dam Power Station Structure Using a Real Scale 3D Model

2019 ◽  
Vol 29 (3) ◽  
pp. 48-59
Author(s):  
Azizi Arbain ◽  
Ahmad Zhafran Ahmad Mazlan ◽  
Mohd Hafiz Zawawi ◽  
Mohd Rashid Mohd Radzi
Keyword(s):  
Vibration Analysis ◽  
3D Model ◽  
Natural Frequencies ◽  
External Disturbance ◽  
Resonance Phenomenon ◽  
Mode Shapes ◽  
Response Analysis ◽  
Power Station ◽  
Real Scale ◽  
Station Structure

Abstract In this paper, the vibration analysis in terms of modal and harmonic responses are investigated for the power station structure of Kenyir Dam in Terengganu, Malaysia. Modal analysis is carried out to provide the dynamic characteristics of the power station which includes the natural frequencies and mode shapes. Meanwhile, the harmonic response analysis is performed by applying the force to the structure to obtain the Frequency Response Function (FRF) in certain range of frequencies. A real scale three-dimensional (3D) model of the Kenyir Dam power station is constructed using SolidWorks software and imported to ANSYS software for the Finite Element (FE) analysis. A proper boundary condition is taken into consideration to demonstrate the real behaviour of the power station structure. From the results, six most significant natural frequencies and mode shapes including the FRF in all three axes are selected. The highest natural frequency value occurred at 5.4 Hz with the maximum deflection of 0.90361 m in the z axis direction. This value is important in order to verify whether the structure can overcome the resonance phenomenon from the external disturbance forces in the future.

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