scholarly journals Cross-sectional Optimization of a Human-Powered Aircraft Main Spar using SQP and Geometrically Exact Beam Model

2018 ◽  
Vol 31 (4) ◽  
pp. 183-190
Author(s):  
Seung-Hoon Kang ◽  
◽  
Byeong-Uk Im ◽  
Hae-Seong Cho ◽  
Sang-Joon Shin
Keyword(s):  
Beam Model ◽  
Cross Sectional ◽  
Geometrically Exact Beam ◽  
Human Powered

scholarly journals A Numerical Solution for Modelling Mooring Dynamics, Including Bending and Shearing Effects, Using a Geometrically Exact Beam Model

2021 ◽  
Vol 9 (5) ◽  
pp. 486
Author(s):  
Tobias Martin ◽  
Hans Bihs
Keyword(s):  
Numerical Solution ◽  
Offshore Wind ◽  
Mooring Line ◽  
Beam Model ◽  
Tight Coupling ◽  
Energy Propagation ◽  
Two Phase ◽  
Geometrically Exact Beam ◽  
Mooring Dynamics ◽  
Rotational Deformation

During the operation of moored, floating devices in the renewable energy sector, the tight coupling between the mooring system and floater motion results in snap load conditions. Before snap events occur, the mooring line is typically slack. Here, the mechanism of energy propagation changes from axial to bending dominant, and the correct modelling of the rotational deformation of the lines becomes important. In this paper, a new numerical solution for modelling the mooring dynamics that includes bending and shearing effects is proposed for this purpose. The approach is based on a geometrically exact beam model and quaternion representations for the rotational deformations. Further, the model is coupled to a two-phase numerical wave tank to simulate the motion of a moored, floating offshore wind platform in waves. A good agreement between the proposed numerical model and reference solutions was found. The influence of the bending stiffness on the motion of the structure was studied subsequently. We found that increased stiffness increased the amplitudes of the heave and surge motion, whereas the motion frequencies were less altered.

Flexible Riser Top Connection Analysis With I-Tube Interface and Bending Hysteresis Effect

2019 ◽  
Author(s):  
Yangye He ◽  
Hailong Lu ◽  
Murilo Augusto Vaz ◽  
Marcelo Caire
Keyword(s):  
Kinematic Hardening ◽  
Bending Moment ◽  
Element Model ◽  
Beam Model ◽  
Flexible Riser ◽  
Nonlinear Bending ◽  
Cross Sectional ◽  
Irregular Wave ◽  
Global Dynamic ◽  
Curvature Distribution

Abstract The flexible riser top connection to the floating production platform is a critical region for fatigue lifetime (re)assessment. The interface with the I-tube and its curved sleeve combined with the gap between the riser and bend stiffener may lead to different curvature distribution when compared to the traditional modeling approach that considers the bend stiffener attached to the pipe. For a more accurate top connection assessment, the flexible riser bending hysteresis can also be directly incorporated in the global dynamic analysis helping to reduce curvature amplitude and lifetime prediction conservatism. This work investigates a 7” flexible riser-bend stiffener top connection with I-tube interface by performing irregular wave global dynamic analyses with the OrcaFlex package and considering a nonlinear bending moment vs curvature riser behavior obtained from a detailed cross sectional model developed in Abaqus. OrcaFlex curvature distribution results are also compared with a quasi-static finite element model that uses an elasto-plastic formulation with kinematic hardening to represent riser hysteresis through an equivalent beam model. A good curvature distribution correlation is observed for both top connection models (OrcaFlex x Abaqus) in the bend stiffener area with reduced amplitudes when riser bending hysteresis is considered.

Development of Parametric Model and Warping Analysis of Composite Beam with Multiple Rigid Regions

2011 ◽  
Vol 326 ◽  
pp. 29-36 ◽  
Author(s):  
Muhammad Mushtaq Tariq ◽  
Zahid Mehmood ◽  
Mohtashim Mansoor ◽  
Malik Nazir Ahmed ◽  
Mustafa Pasha
Keyword(s):  
Composite Materials ◽  
Parametric Model ◽  
Consumer Products ◽  
Parametric Modeling ◽  
Rate Of Change ◽  
Shear Stresses ◽  
Beam Model ◽  
Actual Behavior ◽  
Cross Sectional ◽  
Isotropic Composite

Composite materials are used extensively in aircraft structures, automobiles, sporting goods, and many consumer products. Thin-walled multicell beams made of composite materials, have important applications in aerospace structures. The torsion load on these beams is caused due to distance between Centre of Pressure (CP) and Centre of Gravity (CG) of aerospace vehicle in flight. Warping is a result of torsion load and its analysis is important to predict actual behavior of multicell beams. Study of warping displacements is necessary because prevention of warping leads to stress development. Enhancement in design requires design optimization generated by parametric modeling. Problem of cross-sectional distortion can be controlled through use of rigid diaphragms equally spaced along the length of beam. The aim of present study is to establish a procedure for parametric modeling in presence of rigid regions and simulate warping effects caused by torsion on multicell beams. Quasi-isotropic composite material has been used in multicell beams. Four models of multicell beams analyzed have same length and thickness, but different number of rigid regions and corresponding compatible mesh size. Warping is simulated by FEM based computational program ANSYS, and one; ten and seventy rigid regions inside beam were analyzed. Numerical simulations results show that beam with single rigid region has higher axial warping and more uniform rate of change as compared to beams with multiple rigid regions. It was found that first beam model with one rigid region has warping error 41.6%, second and third model each with ten rigid regions (but different edge size) have 2.5% error in warping, fourth model has 70 rigid regions and it has 0% error in warping. Results show that inaccurate interlaminar shear stresses do not affect the warping behavior of multicell beams. Once the parametric model is defined, then it becomes very quick and easy process to perform warping analysis of composite multicell beam with rigid regions.

A super-convergent thin-walled 3D beam element for analysis of laminated composite structures with arbitrary cross-section

2021 ◽  
pp. 1-23
Author(s):  
M. Talele ◽  
M. van Tooren ◽  
A. Elham
Keyword(s):  
Cross Sections ◽  
Composite Structures ◽  
Three Dimensional ◽  
Laminated Composite ◽  
Beam Element ◽  
Arbitrary Cross Section ◽  
Beam Model ◽  
Cross Sectional ◽  
Thin Walled ◽  
The Cross

Abstract An efficient, fully coupled beam model is developed to analyse laminated composite thin-walled structures with arbitrary cross-sections. The Euler–Lagrangian equations are derived from the kinematic relationships for a One-Dimensional (1D) beam representing Three-Dimensional (3D) deformations that take into account the cross-sectional stiffness of the composite structure. The formulation of the cross-sectional stiffness includes all the deformation effects and related elastic couplings. To circumvent the problem of shear locking, exact solutions to the approximating Partial Differential Equations (PDEs) are obtained symbolically instead of by numerical integration. The developed locking-free composite beam element results in an exact stiffness matrix and has super-convergent characteristics. The beam model is tested for different types of layup, and the results are validated by comparison with experimental results from literature.

scholarly journals Surface Effects on the Vibration and Buckling of Double-Nanobeam-Systems

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Dong-Hui Wang ◽  
Gang-Feng Wang
Keyword(s):  
Natural Frequency ◽  
Surface Elasticity ◽  
Surface Effects ◽  
Nanoelectromechanical Systems ◽  
Beam Model ◽  
Cross Sectional ◽  
Axial Buckling ◽  
Cross Sectional Size ◽  
Euler Bernoulli Beam ◽  
Deformation Modes

Surface effects on the transverse vibration and axial buckling of double-nanobeam-system (DNBS) are examined based on a refined Euler-Bernoulli beam model. For three typical deformation modes of DNBS, we derive the natural frequency and critical axial load accounting for both surface elasticity and residual surface tension, respectively. It is found that surface effects get quite important when the cross-sectional size of beams shrinks to nanometers. No matter for vibration or axial buckling, surface effects are just the same in three deformation modes and usually enhance the natural frequency and critical load. However, the interaction between beams is clearly distinct in different deformation modes. This study might be helpful for the design of nano-optomechanical systems and nanoelectromechanical systems.

A geometrically exact beam model with non-uniform warping coherently derived from the Saint Venant rod

2014 ◽  
Vol 68 ◽  
pp. 33-46 ◽  
Author(s):  
Andrea Genoese ◽  
Alessandra Genoese ◽  
Antonio Bilotta ◽  
Giovanni Garcea
Keyword(s):  
Beam Model ◽  
Geometrically Exact Beam

Energy Harvesting From Aeroelastic Instabilities for Highly Flexible Aircraft

2014 ◽  
Author(s):  
Zahra Sotoudeh
Keyword(s):  
Energy Harvesting ◽  
Smart Materials ◽  
Vibrational Energy ◽  
Piezoelectric Materials ◽  
The Body ◽  
Limit Cycle Oscillation ◽  
Beam Model ◽  
Cross Sectional ◽  
Energy Harvesters ◽  
Cycle Oscillation

Aeroelastic instabilities such as flutter, limit cycle oscillation (LCO), and divergence are traditionally considered undesirable. Designers try to avoid these instabilities by adding enough stiffness or damping to structures. A new approach to suppressing these instabilities is to use smart material to harvest energy from airflow. In this way not only are the aeroelastic instabilities avoided, but also some energy will be harvested. The harvested energy can be used for powering sensors, morphing parts of the structure, and ultimately increasing the performance of the aircraft. Energy harvesting from aeroelastic phenomena can also be used in designing small wind energy harvesters for home use. In this paper we will explore both capabilities. Piezoelectric materials are among the attractive smart materials for energy harvesting. Piezoelectric materials generate electric potential as they deform. We will explore the use of these materials in aeroelastic harvesting. Ref. 1 has a general overview of different forms of vibrational energy harvesting, including the use of piezoelectric materials. Harvesting energy from aeroelastic instabilities is a relatively new area; therefore, the body of literature on this subject is relatively young. Most of the analysis is limited to a 2-D cross-sectional analysis with steady or quasi-steady flow. We will use a 2-D model with an unsteady aerodynamic model as the preliminary result. More realistic cases with a beam model will be added to the final version of the paper. For the beam model, we will use fully intrinsic equations.

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