scholarly journals Aerodynamic Design and Strength Analysis of the Wing for the Purpose of Assessing the Influence of the Bell-Shaped Lift Distribution

Aerospace ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 13
Author(s):  
Pavel Hospodář ◽  
Armand Drábek ◽  
Aleš Prachař
Keyword(s):  
Structural Design ◽  
Bending Moment ◽  
Strength Analysis ◽  
Flight Performance ◽  
Fuel Saving ◽  
Reduce Fuel Consumption ◽  
Aerodynamic Design ◽  
Structural Part ◽  
Optimization Loop ◽  
Good Agreement

This article deals with aerodynamic and structural calculations of several wing designs to compare the influence of the shape on the lift distribution. Various shapes of wings for the required lift and bending moment were optimized to minimize drag and thereby reduce fuel consumption. One example was a wing with a bell-shaped lift distribution, which was proposed by Ludwig Prandtl and has been forgotten over the years. The first part of the paper focuses on minimization of the wing drag coefficient by a low fidelity method and the results are compared with the CFD calculation with good agreement. In the structural part of the analysis, the inner layout of the studied wings was designed. The structural design, containing elementary wing components and optimization loop, was carried out to minimize weight with respect to panel buckling. From these calculations the weights of wings were obtained and compared. In the last part of this study, an analysis of flight performance of an airplane with presented wings was performed for a selected flight mission. Results indicated that, for the free optimized wing, the fuel saving was about six percent.

Experimental Investigation on the Effect of Arm Length on Accuracy of Torque Wrench

2016 ◽  
Vol 853 ◽  
pp. 216-220 ◽  
Author(s):  
You Gang Peng ◽  
Yong Wang
Keyword(s):  
Experimental Investigation ◽  
Structural Design ◽  
Bending Moment ◽  
Theoretical Solution ◽  
Calibration Laboratory ◽  
Moment Measurement ◽  
Torque Wrench ◽  
Actual Use ◽  
Good Agreement

Experiments were carried out to investigate the effect of arm length on the accuracy of two typical conventional torque wrenches, namely, setting type torque wrench (STW) and indicating type torque wrench (ITW). The experiment results demonstrate that the measurement values of STW rises rapidly with decreasing arm length while measured torque of ITW shows irrelevant to arm length. Theoretical solution with respect to STW shows quite good agreement with experiment results. Irrelevance of arm length regard to ITW may be attributable to compensation of bending moment measurement due to proper arrangement of circuit and structural design. In order to conduct a proper assessment at a calibration laboratory or ensure its reliability with reference to actual use conditions, a torque wrench should be used by a customer at the loading point as recommended.

Buckling/Ultimate Strength Evaluation for Continuous Stiffened Panel Under Combined Shear and Thrust

2016 ◽  
Author(s):  
Hiroaki Ogawa ◽  
Tomoki Takami ◽  
Akira Tatsumi ◽  
Yoshiteru Tanaka ◽  
Shinichi Hirakawa ◽  
...  
Keyword(s):  
Ultimate Strength ◽  
Fem Analysis ◽  
Strength Analysis ◽  
Stiffened Panel ◽  
Fe Modeling ◽  
Test Results ◽  
Strength Evaluation ◽  
Shear Buckling ◽  
Collapse Behavior ◽  
Good Agreement

In this study, FE modeling method for the buckling/ultimate strength analysis of a continuous stiffened panel under combined shear and thrust is proposed. In order to validate the proposed method, shear buckling collapse tests of a stiffened panel and FEM analysis are carried out. As the result of these, it is confirmed that the buckling collapse behavior and the ultimate strength estimated by the proposed method are in good agreement with the test results.

On the Effect of Hull Girder Flexibility on the Vertical Wave Bending Moment for Ultra Large Container Vessels

2012 ◽  
Author(s):  
Ingrid Marie Vincent Andersen ◽  
Jørgen Juncher Jensen
Keyword(s):  
Bending Moment ◽  
Main Concern ◽  
Hull Girder ◽  
Numerical Predictions ◽  
Strip Theory ◽  
Reliability Method ◽  
Non Linear ◽  
Large Container ◽  
The Waves ◽  
Good Agreement

Currently, a number of very large container ships are being built and more are on order, and some concerns have been expressed about the importance of the reduced hull girder stiffness to the wave-induced loads. The main concern is related to the fatigue life, but also a possible increase in the global hull girder loads as consequence of the increased hull flexibility must be considered. This is especially so as the rules of the classification societies do not explicitly account for the effect of hull flexibility on the global loads. In the present paper an analysis has been carried out for the 9,400 TEU container ship used as case-ship in the EU project TULCS (Tools for Ultra Large Container Ships). A non-linear time-domain strip theory is used for the hydrodynamic analysis of the vertical bending moment amidships in sagging and hogging conditions for a flexible and a rigid modelling of the ship. The theory takes into account non-linear radiation forces (memory effects) through the use of a set of higher order differential equations. The non-linear hydrostatic restoring forces and non-linear Froude-Krylov forces are determined accurately at the instantaneous position of the ship in the waves. Slamming forces are determined by a standard momentum formulation. The hull flexibility is modelled as a non-prismatic Timoshenko beam. Generally, good agreement with experimental results and more accurate numerical predictions has previously been obtained in a number of studies. The statistical analysis is done using the First Order Reliability Method (FORM) supplemented with Monte Carlo simulations. Furthermore, strip-theory calculations are compared to model tests in regular waves of different wave lengths using a segmented, flexible model of the case-ship and good agreement is obtained for the longest of the waves. For the shorter waves the agreement is less good. The discrepancy in the amplitudes of the bending moment can most probably be explained by an underestimation on the effect of momentum slamming in the strip-theory applied.

A review of aerodynamic studies on dragonfly flight

2019 ◽  
Vol 233 (18) ◽  
pp. 6519-6537 ◽  
Author(s):  
Erfan Salami ◽  
Thomas A Ward ◽  
Elham Montazer ◽  
Nik Nazri Nik Ghazali
Keyword(s):  
Web Of Science ◽  
Micro Air Vehicles ◽  
Flight Performance ◽  
Aerodynamic Design ◽  
Journal Articles ◽  
Dragonfly Wing ◽  
Thomson Reuters ◽  
Gliding Flight ◽  
And Control ◽  
Air Vehicles

In the recent decades, the design and development of biomimetic micro air vehicles have gained increased interest by the global scientific and engineering communities. This has given greater motivation to study and understand the aerodynamics involved with winged insects. Dragonflies demonstrate unique and superior flight performance than most of the other insect species and birds. They are capable of sustained gliding flight as well as hovering and able to change direction very rapidly. Pairs of independently controlled forewings and hindwings give them an agile flying ability. This article presents a review of all published journal articles, listed in the Thomson-Reuters Web-of-Science database (1985–2018), that are related to the flight aerodynamics of dragonflies or micro air vehicles that biomimic them. The effects of dragonfly wing motions and interactions (between forewing and hindwing) that are necessary to generate the appropriate aerodynamic forces in different flight modes are described. The associated power requirements of these modes are also addressed. This article aims to provide a valuable reference to the aerodynamic design and control of dragonfly-inspired biomimetic micro air vehicles.

Large deflection of elastoplastic, non-linear strain-hardening cantilevers

2001 ◽  
Vol 216 (4) ◽  
pp. 433-446 ◽  
Author(s):  
X Huang ◽  
B Wang ◽  
G Lu ◽  
T X Yu
Keyword(s):  
Strain Hardening ◽  
Large Deflection ◽  
Rectangular Cross Section ◽  
Bending Moment ◽  
Linear Strain ◽  
Non Linear ◽  
Theoretical Predictions ◽  
Strain Relationship ◽  
Inclined Angle ◽  
Good Agreement

This paper concerns the large deflection of elastoplastic, non-linear strain-hardening cantilevers of rectangular cross-section, for which the stress-strain relationship after yielding is described by σ= K1εq. Both the bending moment and axial force are included in the yielding criterion, and the corresponding strain increments obey the associated normality rule. Comparisons between the experimental data and the theoretical predictions are made for mild steel cantilevers subjected to a tip force with an inclined angle ϕ = 67.5,90 and 157° respectively. Reasonable agreement is obtained. The theoretical analysis has described the large deflection behaviour of the cantilever and is in good agreement with tests.

scholarly journals Prediction and Measurement of Machining Distortion in Aluminium Alloy 7085

2014 ◽  
Vol 996 ◽  
pp. 640-645 ◽  
Author(s):  
Zhang Zheng ◽  
Liang Li ◽  
Yin Fei Yang ◽  
Ning He ◽  
Wei Zhao
Keyword(s):  
Numerical Methods ◽  
Stress Field ◽  
Residual Stresses ◽  
Aluminium Alloy ◽  
Experimental Verification ◽  
Structural Part ◽  
Cold Compression ◽  
Manufacturing Operations ◽  
Part Distortion ◽  
Good Agreement

It is essential to accurately predict or model the residual stresses in a material resulting from various manufacturing operations. Numerical methods were used in this study to predict the residual stresses after quenching and cold compression of an Al 7085 forged block. Experimental verification was provided by comparing the measured distortions due to a relaxation of the residual stresses with the predictions obtained by using a simulated stress field. The validation was carried out on a simplified structural part. The measured and simulated distortions were found to be in good agreement with each other. The results indicated that part distortion is attributable to the relaxation of bulk residual stresses.

Effect of Dielectric-Layer on the Stress Field of Micro Cantilever Beams at the Onset of Pull-In Instability

2013 ◽  
Vol 30 (1) ◽  
pp. 49-56 ◽  
Author(s):  
E. Yazdanpanahi ◽  
A. Noghrehabadi ◽  
M. Ghalambaz
Keyword(s):  
Stress Distribution ◽  
Dielectric Layer ◽  
Adomian Decomposition Method ◽  
Bending Moment ◽  
Distributed Parameter ◽  
Cantilever Beams ◽  
Layer Parameter ◽  
Adomian Decomposition ◽  
Micro Cantilever ◽  
Good Agreement

ABSTRACTIn this paper, stress distribution of micro cantilever beams in the presence of a dielectric-layer is studied using an analytic method. The Modified Adomian Decomposition Method (MADM) is applied to obtain a semi-analytical solution for a distributed parameter model of the micro cantilever beam. The important parameters for designing and manufacturing micro-actuators such as shear force, bending moment and stress distribution along the cantilevers are computed for different values of the dielectric-layer parameter. The results of MADM are compared with the numerical results, and they found in good agreement. It is found that increase of the dielectric-layer parameter increases the dimensionless pull-in voltage, tip deflection, internal stress and bending moment of the micro cantilever actuators at the onset of pull-in instability.

FEM Stress Analysis and Sealing Performance in Pipe Flange Connections With Adhesive Subjected to Internal Pressure and External Bending Moments

2005 ◽  
Author(s):  
Masahide Katsuo ◽  
Toshiyuki Sawa ◽  
Yuki Kikuchi
Keyword(s):  
Internal Pressure ◽  
Stress Analysis ◽  
Bending Moment ◽  
Fem Analysis ◽  
Bending Moments ◽  
3 Dimensional ◽  
Leakage Test ◽  
Sealing Performance ◽  
Flange Thickness ◽  
Good Agreement

This study deals with the stress analysis and the estimation of sealing performance of the pipe flange connections with an adhesive under an internal pressure and an external bending moment are analyzed by using the 3-dimensional elastic finite element method (FEM). The experiment of the leakage test of the connections with an adhesive was carried out by applying the above loads to the connections. From the FEM analysis, the following results were obtained; (1) when an internal pressure is applied to the flange connections, the compressive stress at the interface between a flange and an adhesive increases proportionally from the inner side of the interface to outside, and (2) when an internal pressure and a bending moment apply to the flange connections, the stress distribution at the half part of the interface increases as the external bending moments increase and also Young’s modulus of the adhesive increases. From the experiments, the following results were obtained: (1) sealing performance of the pipe flange connections with an adhesive under an internal pressure and an external bending moment increases as the flange thickness and an initial clamping force of bolts increases and (2) the sealing performances were not found between the connections with an adhesive and that with a gasket combining an adhesive. Furthermore, the numerical results are in fairly good agreement with the experimental results.

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