Synthetic Design of High Aspect Ratio Folding Wings Based on Aeroelastic Analysis

2014 ◽  
Vol 607 ◽  
pp. 409-412
Author(s):  
Sheng Li Lv ◽  
Cheng Wang ◽  
Yang Biao Ou ◽  
Guang Jun Yang ◽  
Xiao Yan Tong
Keyword(s):  
Engineering Application ◽  
Element Model ◽  
Expansion Process ◽  
Sweep Angle ◽  
Flutter Speed ◽  
Aeroelastic Analysis ◽  
Flutter Analysis ◽  
Practical Engineering ◽  
Analysis Models ◽  
Relationship Of

Finite element model of folding wings was designed in the light of structural scheme, and each part of the model used composites. Different aeroelastic analysis models were built from emission to cruise, and then the models were made the study focus on flutter analysis. The result showed the change relationship of the critical flutter speed of wings and flutter frequency with sweep angle in state of expansion process, and the change relationship of the critical flutter speed of wings and flutter frequency of folding wings with cruising altitude and cruise Mach number in state of cruise. The whole flight state was analyzed if the folding wings might flutter, and if it took place the structure optimization of wings was needed. Simulation results have a certain guiding significance for practical engineering application.

scholarly journals Kinematics, Dynamics, and Optimal Control of Pneumatic Hexapod Robot

2017 ◽  
Vol 2017 ◽  
pp. 1-16 ◽  
Author(s):  
Long Bai ◽  
Lu-han Ma ◽  
Zhifeng Dong ◽  
Xinsheng Ge
Keyword(s):  
Engineering Application ◽  
Pseudospectral Method ◽  
Hexapod Robot ◽  
Dynamics Modeling ◽  
Rescue Operation ◽  
The Matrix ◽  
Calculation Results ◽  
Practical Engineering ◽  
Body Joints ◽  
Relationship Of

Pneumatic hexapod robot is driven by inert gas carried by itself, which has board application prospect in rescue operation of disaster conditions containing flammable gas. Cruising ability is main constraint for practical engineering application which is influenced by kinematics and dynamics character. The matrix operators and pseudospectral method are used to solve dynamics modeling and numerical calculation problem of robot under straight line walking. Kinematics model is numerically solved and relationship of body, joints, and drive cylinders is obtained. With dynamics model and kinematics boundary conditions, the optimal input gas pressure of leg swing and body moving in one step is obtained by pseudospectral method. According to action character of magnetic valve, calculation results of control inputs satisfy engineering design requirements, and cruising ability under finite gas is obtained.

Research and Application of Composite Girder with Concrete Filled Tubular Flange

2011 ◽  
Vol 250-253 ◽  
pp. 2538-2541
Author(s):  
Chun Sheng Wang ◽  
Xiao Liang Zhai ◽  
Jing Wei Zhu ◽  
Shuang Jie Zheng
Keyword(s):  
Engineering Application ◽  
Bridge Engineering ◽  
Design Rules ◽  
Static And Dynamic Analysis ◽  
Girder Bridges ◽  
Composite Girder ◽  
Bridge Structures ◽  
Practical Engineering ◽  
Analysis Models ◽  
Mechanical Characters

In order to promote the applications of steel and concrete composite girder with concrete-filled tubular up-flange (SCCGCFTF) in practical bridge engineering, some actual issues for SCCGCFTF bridge structures have been discussed. The finite element static and dynamic analysis models of SCCGCFTF and conventional composite I-shape girder (CCIG) bridge structures were established. Then the stiffness, stress and dynamic characteristics of these composite girder bridges were studied and compared. Based on the numerical analysis results, the mechanical characters of SCCGCFTF bridges are obtained, and some design rules for SCCGCFTF bridges are also proposed. The analysis results show that SCCGCFTF bridges have high practical engineering application value.

scholarly journals Experimental Investigation and Numerical Modeling of Elastic Modulus Variation with Stress during Hydration and Expansion Process of Static Cracking Agent

2021 ◽  
Vol 11 (9) ◽  
pp. 3955
Author(s):  
Zhaoguo Qiu ◽  
You Ji ◽  
Fengpeng Zhang ◽  
Guangliang Yan
Keyword(s):  
Elastic Modulus ◽  
Poisson’S Ratio ◽  
Compressive Loading ◽  
Engineering Application ◽  
Element Model ◽  
Poisson's Ratio ◽  
Hydration Process ◽  
Expansion Process ◽  
Chemical Expansion ◽  
Amplitude Coefficient

Based on the “axial-output method”, the time histories of radial and axial expansive pressures during the hydration process of static cracking agent (SCA) in a cylinder with various diameters were obtained by experiments. With the load input taken as the product of the normalized axial expansive pressure and the amplitude coefficient, a finite element model was established to simulate the experimental chemical expansion process of SCA. The relationships between elastic modulus, radial and axial expansive pressures were then obtained. The results indicate that the elastic modulus increases with increasing radial and axial expansive pressures, and then tends to be constant. The effect of Poisson’s ratio was discussed with the elastic modulus unchanged. It is shown that the Poisson’s ratio is inversely proportional to the amplitude coefficient, and has no effect on the ratio between the axial and radial expansive pressures. Finally, a mechanical model for the variation of elastic modulus with stress during the hydration process of static cracking agent was established in terms of the major principal stress. The model was verified by the experimental results, which can be extended for numerical simulation of SCA expansion under other compressive loading conditions, and then provide practical mechanical parameters for engineering application of SCA.

VIBRATION AND TRANSONIC FLUTTER ANALYSIS FOR F-16 STORES CONFIGURATION CLEARANCE

2006 ◽  
Vol 06 (03) ◽  
pp. 377-395 ◽  
Author(s):  
ROBERT A. CANFIELD ◽  
RAYMOND G. TOTH ◽  
REID MELVILLE
Keyword(s):  
Frequency Tuning ◽  
Ground Vibration ◽  
Element Model ◽  
Limit Cycle Oscillation ◽  
Flight Tests ◽  
Flutter Speed ◽  
Flutter Analysis ◽  
Transonic Flutter ◽  
Cycle Oscillation ◽  
Nonlinear Aerodynamic

This paper supports quick and accurate prediction of the flutter onset speed of an F-16 Block 40/50 configured with external stores in the transonic flight regime. Current flutter prediction methods are reviewed and hypothesized mechanisms for limit cycle oscillation (LCO) are summarized. New efforts to correlate transonic small disturbance (TSD) theory methods with flight tests are outlined. Vibration analysis and structural optimization of an F-16 finite element model were used to match ground vibration testing results. Frequency tuning was found to be critical for accurate flutter speed predictions. Sensitivity to nonlinear aerodynamic effects and store modeling was examined.

Flutter Analysis of Hypersonic Wings Subject to Thermal Load

2011 ◽  
Vol 105-107 ◽  
pp. 466-469
Author(s):  
Yao Bin Niu ◽  
Zhong Wei Wang
Keyword(s):  
Elevated Temperature ◽  
Material Properties ◽  
Thermal Load ◽  
Thermal Stresses ◽  
Vital Role ◽  
Aerodynamic Loads ◽  
Flutter Speed ◽  
Aeroelastic Analysis ◽  
Flutter Analysis ◽  
Nature Frequency

Aeroelastic analysis plays a vital role in the design of hypersonic wings. The thermal flutter of hypersonic tail under different materials at different temperature is analyzed by using MSC.NASTRAN, and the hypersonic piston theory is used for the modeling of supersonic aerodynamic loads. The research results showed: nature frequency is reduced as temperature increased, elevated temperature tend to reduce model stiffness due to changes in material properties and development of thermal stresses. Increased temperature will decrease the flutter velocity, flutter speed of tail is different with different material of titanium, but the trend and the value of variety of flutter speed are same as temperature increase. When material is different, the value of variety of flutter speed is also different.

NONLINEAR AEROELASTIC ANALYSIS OF A MORPHING FLAP

2012 ◽  
Vol 22 (05) ◽  
pp. 1250099 ◽  
Author(s):  
DAOCHUN LI ◽  
SHIJUN GUO ◽  
YUANYUAN HE ◽  
JINWU XIANG
Keyword(s):  
Element Model ◽  
Curved Beams ◽  
Reduced Order ◽  
Actuation Mechanism ◽  
Influence Coefficients ◽  
Aeroelastic Analysis ◽  
Aeroelastic Model ◽  
Freeplay Nonlinearity ◽  
Flutter Analysis ◽  
Structural Mass

A morphing flap integrated with an actuation mechanism was designed and investigated. Based on structure parameters from static experiments, a finite element model of the flap was created within MSC Patran software. Normal modal analysis and linear flutter analysis were carried out firstly. V–g and V–f curves were obtained to determine the critical flutter speeds with and without the actuation mechanism. Structural mass, damping, stiffness, and aerodynamic matrixes were printed with DMAP language to form an aeroelastic equation in modal coordinate. The freeplay nonlinearity between disks attached to the curved beams and wing skins was considered in the aeroelastic analysis. An unsteady aerodynamic influence coefficients matrix was calculated by Roger's approximation. The nonlinear aeroelastic equation in modal coordinate was solved by an iterative program written with MATLAB software. Based on the reduced-order aeroelastic model, the effect of freeplay on aeroelastic responses was investigated. Numerical results show that the freeplay nonlinearity may reduce critical flutter speed, leading to supercritical Hopf bifurcation.

PERSEPSI PEMAHAMAN PERANAN AUDITOR, ETIKA AUDITOR DAN INDEPENDENSI AUDITOR INTERNAL DALAM MEWUJUDKAN GOOD UNIVERSITY GOVERNANCE DENGAN GAYA KEPEMIMPINAN SEBAGAI VARIABEL MODERASI

2019 ◽  
Vol 4 (1) ◽  
pp. 474
Author(s):  
Fipitriany Any
Keyword(s):  
Leadership Style ◽  
University Governance ◽  
Primary Data ◽  
Study Program ◽  
Internal Auditor ◽  
Internal Auditors ◽  
Analysis Models ◽  
Relationship Of ◽  
Role Ethics

ABSTRACT The purpose of this study is to examine and analyze the influence of the role, ethics, and independence of internal auditors in implementing good university governance (GUG) with leadership style as a moderation variable. Multiple linear regression and moderation regression analysis models are used to test the hypothesis. The primary data are obtained through questionnaires that are distributed to the respondents, namely the dean and head of study program at the UniversitasBinaDarma and UniversitasMuhammadiyahPalembang. The results of this study indicate that the instruments in each variable proved to be valid and reliable. Based on the results of hypothesis testing, it can be seen that simultaneously the variable of role, ethics, and independence of internal auditors have positively and significantly effect in implementing good university governance (GUG). These results provide justification or endorsement of the theoretical truths used as the theoretical references of Stewardship Theory and Attitude and Behavioral Theory. Based on the partial test, role of auditor does not significantly affect the variable of GUG, but ethics and independence variable are found to be significant in influencing GUG. The leadership style is negative and insignificant in moderating the role of internal auditors and GUC and also the independence of internal auditor and GUC. The leadership style is found to be positive and insignificant in moderating the relationship of internal auditors’ ethics and GUC.Keywords        Role, Ethics, Independence, Internal Auditor, Leadership Style, Good University Governance  ABSTRAK Tujuan dari penelitian ini adalah untuk menguji dan menganalisis pengaruh peran, etika, dan independensi auditor internal dalam menerapkan good university governance (GUG) dengan gaya kepemimpinan sebagai variabel moderasi. Model analisis regresi linier berganda dan regresi moderasi digunakan untuk menguji hipotesis. Data primer diperoleh melalui kuesioner yang dibagikan kepada responden, yaitu dekan dan ketua program studi di Universitas Bina Darma dan Universitas MuhammadiyahPalembang. Hasil penelitian ini menunjukkan bahwa instrumen dalam setiap variabel terbukti valid dan dapat diandalkan. Berdasarkan hasil pengujian hipotesis dapat dilihat bahwa secara simultan variabel peran, etika, dan independensi auditor internal berpengaruh positif dan signifikan dalam penerapan good university governance (GUG). Hasil ini memberikan pembenaran atau pengesahan kebenaran teoretis yang digunakan sebagai referensi teoretis dari Teori Penatalayanan dan Teori Sikap dan Perilaku. Berdasarkan uji parsial, peran auditor tidak secara signifikan mempengaruhi variabel GUG, tetapi variabel etika dan independensi ditemukan signifikan dalam mempengaruhi GUG. Gaya kepemimpinan negatif dan tidak signifikan dalam memoderasi peran auditor internal dan GUC dan juga independensi auditor internal dan GUC. Gaya kepemimpinan ditemukan menjadi positif dan tidak signifikan dalam memoderasi hubungan etika auditor internal dan GUC Kata Kunci            Peran, Etika, Independensi, Auditor Internal, Gaya Kepemimpinan, Tata Kelola Universitas

Dynamic Characteristics and Stability Analysis of Two-Dimensional (2D) Electro-Hydraulic Proportional Directional Valve

2015 ◽  
Author(s):  
S. Li ◽  
J. Ruan ◽  
B. Meng ◽  
W. A. Jia ◽  
H. Y. Xie
Keyword(s):  
Dynamic Characteristics ◽  
Magnetic Force ◽  
Engineering Application ◽  
Proportional Valve ◽  
Acceptable Range ◽  
Hydrostatic Force ◽  
Practical Engineering ◽  
Direct Operation ◽  
Electrohydraulic Valve ◽  
Proportional Directional Valve

A 2D electrohydraulic proportional directional valve is proposed, which integrates both direct and pilot operation of the valve. In this valve, the output magnetic force of the proportional solenoid is converted to rotate the spool through a thrust-torsion coupling and thus the pressure in the valve sensitive chamber is varied. The varied pressure exerted on the areas of the spool end produces a hydrostatic force to move the spool linearly, which will rotate the spool reversely. Theoretical analysis is carried to the proposed valve and the effects of the key geometric parameters on the dynamic characteristics of the 2D valve and stability are investigated. Experiments are also designed to access to the characteristics of the valve working under direct and pilot operation. The 2D electrohydraulic valve can work properly for both direct operation and pilot operation. The hysteresis and frequency response are measured and the results are within the acceptable range in practical engineering application required of the directional proportional valve.

Optimization Design of Pressure Shell in Underwater Vehicle Based on Response Surface Model

2009 ◽  
Vol 419-420 ◽  
pp. 89-92
Author(s):  
Zhuo Yi Yang ◽  
Yong Jie Pang ◽  
Zai Bai Qin
Keyword(s):  
Finite Element ◽  
Response Surface ◽  
Optimization Design ◽  
Engineering Application ◽  
Element Model ◽  
Response Surface Model ◽  
Design Stage ◽  
Surface Model ◽  
Design Variables ◽  
Structure Strength

Cylinder shell stiffened by rings is used commonly in submersibles, and structure strength should be verified in the initial design stage considering the thickness of the shell, the number of rings, the shape of ring section and so on. Based on the statistical techniques, a strategy for optimization design of pressure hull is proposed in this paper. Its central idea is that: firstly the design variables are chosen by referring criterion for structure strength, then the samples for analysis are created in the design space; secondly finite element models corresponding to the samples are built and analyzed; thirdly the approximations of these analysis are constructed using these samples and responses obtained by finite element model; finally optimization design result is obtained using response surface model. The result shows that this method that can improve the efficiency and achieve optimal intention has valuable reference information for engineering application.

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