scholarly journals Verification and Validation of Supersonic Flutter of Rudder Model for Experiment

2021 ◽  
Author(s):  
Ju Qiu ◽  
Chaofeng Liu
Keyword(s):  
Finite Element ◽  
Optimization Technique ◽  
Wind Tunnel Test ◽  
Ground Vibration ◽  
Element Model ◽  
Experimental Information ◽  
Design Variables ◽  
Potential Applications ◽  
Supersonic Flutter ◽  
The Finite Element Model

The abrupt and explosive nature of flutter is a dangerous failure mode, which is closely related to the structural modes. In this work, the principal goal of the study is to produce the model, which is used very accurately for flutter predictions. Mode correctness of the model can correct the test deflects by the optimization technique----Sequential Quadratic Programming (SQP). The optimization of two finite element models for two flight conditions, transonic and supersonic speeds, had the different objectives which were defined by the nonlinear and linear eigenvector errors. The first and second frequencies were taken as constraints. And the stiffness of the rotation shaft was also restricted to some limits. The stiffness of the rudder axle was defined as design variables. Experiments were performed for considering springs both in plunge and in torsion of the rudder shaft. When the comparison between experimental information and analyzed calculations is described, generally excellent agreement is obtained between experimental and calculated results, and aeroelastic instability is predicted that agrees with experimental observations. Comments are also given concerning improvements of the flutter speed to be made to the model with changing stiffness of the rudder axle. Most importantly, V&V Method is used to provide the confidence in the results from simulation in this paper. Firstly, it introduces experimental data from Ground Vibration Test to build up or modify the Finite Element Model, during the Verification phase, which makes simulated models closer to the real world and guarantees satisfaction of final computed results to requirements, such as airworthiness. Secondly, the flutter consequence is validated by wind tunnel test. These enhancements could find potential applications in industrial problems.

Damage identification in concrete structures with uncertain but bounded measurements

2016 ◽  
Vol 16 (6) ◽  
pp. 649-662 ◽  
Author(s):  
Suryakanta Biswal ◽  
Ananth Ramaswamy
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Posterior Probability ◽  
Optimization Technique ◽  
Concrete Structures ◽  
Element Model ◽  
Reinforced Concrete Beams ◽  
Finite Element Software ◽  
Damage Indices ◽  
The Finite Element Model

The major sources of error in the measurements of concrete structures are the gauge sensitivities, calibration accuracies, amplitude linearities, and temperature corrections to the gauge sensitivities, which are given in terms of plus–minus ranges, and the round off errors in the measured responses, which are better represented by interval bounds. An algorithm is proposed adapting the existing modified Metropolis Hastings algorithm for estimating the posterior probability of the damage indices as well as the posterior probability of the bounds of the interval parameters, when the measurements are given in terms of interval bounds. A damage index is defined for each element of the finite element model considering the parameters of each element are intervals. Methods are developed for evaluating response bounds in the finite element software ABAQUS, when the parameters of the finite element model are intervals. The proposed method is validated against reinforced concrete beams with three damage scenarios mainly (1) loss of stiffness, (2) loss of mass, and (3) loss of bond between concrete and reinforcement steel, which have been tested in our laboratory. Comparison of the prediction from the proposed method with those obtained from Bayesian analysis and interval optimization technique show improved accuracy and computational efficiency in addition to better representation of measurement uncertainties through interval bounds.

scholarly journals Model Updating and Aeroelastic Correlation of a Scaled Wind Tunnel Model for Active Flutter Suppression Test

Aerospace ◽  
2021 ◽  
Vol 8 (11) ◽  
pp. 334
Author(s):  
Domenico Di Leone ◽  
Francesco Lo Balbo ◽  
Alessandro De Gaspari ◽  
Sergio Ricci
Keyword(s):  
Finite Element ◽  
Wind Tunnel ◽  
Model Updating ◽  
Three Dimensional ◽  
Wind Tunnel Test ◽  
Ground Vibration ◽  
Element Model ◽  
Sensitivity Analyses ◽  
Flutter Suppression ◽  
Active Flutter Suppression

This article presents a modal correlation and update carried out on an aeroelastic wind tunnel demonstrator representing a conventional passenger transport aircraft. The aim of this work is the setup of a corresponding numerical model that is able to capture the flutter characteristics of a scaled aeroelastic model designed to investigate and experimentally validate active flutter suppression technologies. The work described in this paper includes different finite element modeling strategies, the results of the ground vibration test, and finally the strategies adopted for modal updating. The result of the activities is a three-dimensional hybrid finite element model that is well representative of the actual aeroelastic behavior identified during the wind tunnel test campaign and that is capable of predicting the flutter boundary with an error of 1.2%. This model will be used to develop active flutter suppression controllers, as well as to perform the sensitivity analyses necessary to investigate their robustness.

Topological Optimization Design of Cistern Stents of the Planomiller Machine Based on Hyperworks

2011 ◽  
Vol 421 ◽  
pp. 423-426
Author(s):  
Fu Yun Liu ◽  
Ying Sun ◽  
Tian Chao Yu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Optimization Design ◽  
Element Model ◽  
Topological Optimization ◽  
Structural Deformation ◽  
Engineering Practice ◽  
Geometry Model ◽  
Design Variables ◽  
The Finite Element Model

Planomiller is a milling machine that widely used in processes of large parts. Cistern stents is a component of planomiller supporting the sink. In this paper, topological optimization of Cistern stents is implemented to reduce its weight. Firstly geometry model of Cistern stents is built in SolidWorks, a finite element model of Cistern stents is established. Then loads and boundary conditions are loaded to the finite element model according to engineering practice. Finally density of units is set as the design variables, energy of structural deformation is set as the objective function, Cistern stents can be optimized by optimizing analysis. The compared results show that the proposed optimization design is effective.

scholarly journals Updating the finite element model of a Colombian Bridge with Ansys

DYNA ◽  
2020 ◽  
Vol 87 (212) ◽  
pp. 209-218
Author(s):  
Diego Sequera Gutierrez ◽  
Luis Felipe Solano Rodríguez ◽  
Edgar Eduardo Muñoz Díaz ◽  
Yezid Alexander Alvarado Vargas ◽  
Jesús Daniel Villalba Morales ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Structural Model ◽  
Natural Frequencies ◽  
Element Model ◽  
Ambient Vibration ◽  
Normal Operation ◽  
Design Variables ◽  
Ambient Vibration Measurements ◽  
The Finite Element Model

Updating structural model is a knowledge field that have been studied in the last decades to guarantee the reliability on the model defined to represent the behavior of a structure, but generally implies the use of different software to carry out the different parts of the process. This paper presents the updating of the finite element model of a curve-alignment reinforced concrete bridge located near to the city of Ubaté in Colombia by using the optimization tool available in software Ansys and ambient vibration measurements. The use of such type of information avoids to carry out forced-vibration test, which affect the normal operation of the bridge. The objective function corresponds to the minimization of the error between analytical and experimental natural frequencies of the bridge. The design variables correspond to the material properties of the concrete and the elastomeric bearings. Results show that the error was decreased to less than 2%. The sensibility analysis allowed to determine which variables are more sensible to affect the natural frequencies in the structure.

Redrawing Operation a Star Shape from Cylindrical Shape Using Experimental and FE Analysis

2020 ◽  
Vol 38 (1A) ◽  
pp. 25-32
Author(s):  
Waleed Kh. Jawad ◽  
Ali T. Ikal
Keyword(s):  
Finite Element ◽  
Effective Strain ◽  
Element Model ◽  
Cylindrical Shape ◽  
Element Analysis ◽  
Punch Force ◽  
Maximum Value ◽  
Element Simulation ◽  
Blank Sheet ◽  
The Finite Element Model

The aim of this paper is to design and fabricate a star die and a cylindrical die to produce a star shape by redrawing the cylindrical shape and comparing it to the conventional method of producing a star cup drawn from the circular blank sheet using experimental (EXP) and finite element simulation (FES). The redrawing and drawing process was done to produce a star cup with the dimension of (41.5 × 34.69mm), and (30 mm). The finite element model is performed via mechanical APDL ANSYS18.0 to modulate the redrawing and drawing operation. The results of finite element analysis were compared with the experimental results and it is found that the maximum punch force (39.12KN) recorded with the production of a star shape drawn from the circular blank sheet when comparing the punch force (32.33 KN) recorded when redrawing the cylindrical shape into a star shape. This is due to the exposure of the cup produced drawn from the blank to the highest tensile stress. The highest value of the effective stress (709MPa) and effective strain (0.751) recorded with the star shape drawn from a circular blank sheet. The maximum value of lamination (8.707%) is recorded at the cup curling (the concave area) with the first method compared to the maximum value of lamination (5.822%) recorded at the cup curling (the concave area) with the second method because of this exposure to the highest concentration of stresses. The best distribution of thickness, strains, and stresses when producing a star shape by

Analysis of Hydroelectric Unit’s Upper Bracket Based on Test and FEM

2014 ◽  
Vol 721 ◽  
pp. 131-134
Author(s):  
Mi Mi Xia ◽  
Yong Gang Li
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Element Model ◽  
The Finite Element Method ◽  
Ansys Software ◽  
Element Analysis ◽  
Hydroelectric Unit ◽  
The Finite Element Analysis ◽  
Strain Rosette ◽  
The Finite Element Model

To research the load upper bracket of Francis hydroelectric unit, then established the finite-element model, and analyzed the structure stress of 7 operating condition points with the ANSYS software. By the strain rosette test, acquired the data of stress-strain in the area of stress concentration of the upper bracket. The inaccuracy was considered below 5% by analyzing the contradistinction between the finite-element analysis and the test, and match the engineering precision and the test was reliable. The finite-element method could be used to judge the stress of the upper bracket, and it could provide reference for the Structural optimization and improvement too.

Topology Optimization Design of High Pressure Storage Tank Structure

2012 ◽  
Vol 430-432 ◽  
pp. 828-833
Author(s):  
Qiu Sheng Ma ◽  
Yi Cai ◽  
Dong Xing Tian
Keyword(s):  
Finite Element ◽  
High Pressure ◽  
Topology Optimization ◽  
Storage Tank ◽  
Optimization Design ◽  
Influence Factors ◽  
Element Model ◽  
Design Variables ◽  
Calculation Results ◽  
Pressure Storage

In this paper, based on ANSYS the topology optimization design for high pressure storage tank was studied by the means of the finite element structural analysis and optimization. the finite element model for optimization design was established. The design variables influence factors and rules on the optimization results are summarized. according to the calculation results the optimal design result for tank is determined considering the manufacturing and processing. The calculation results show that the method is effective in optimization design and provide the basis to further design high pressure tank.

Structural Optimization of the Telescopic Boom of a Certain Type of Truck-Mounted Crane

2014 ◽  
Vol 548-549 ◽  
pp. 383-388
Author(s):  
Zhi Wei Chen ◽  
Zhe Cui ◽  
Yi Jin Fu ◽  
Wen Ping Cui ◽  
Li Juan Dong ◽  
...  
Keyword(s):  
Finite Element ◽  
Static Analysis ◽  
Cross Sections ◽  
Optimization Design ◽  
Structural Parameters ◽  
Vertical Direction ◽  
Element Model ◽  
Shape Parameters ◽  
Conventional Design ◽  
Design Variables

Parametric finite element model for a commonly used telescopic boom structure of a certain type of truck-mounted crane has been established. Static analysis of the conventional design configuration was performed first. And then an optimization process has been carried out to minimize the total weight of the telescopic structures. The design variables include the geometric shape parameters of the cross-sections and the integrated structural parameters of the telescopic boom. The constraints include the maximum allowable equivalent stresses and the flexure displacements at the tip of the assembled boom structure in both the vertical direction and the circumferential direction of the rotating plane. Compared with the conventional design, the optimization design has achieved a significant weight reduction of up to 24.3%.

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