The Experts below are selected from a list of 1809 Experts worldwide ranked by ideXlab platform
T.h.g. Megson - One of the best experts on this subject based on the ideXlab platform.
-
Chapter 18 – Torsion of Beams
Aircraft Structures for Engineering Students, 2017Co-Authors: T.h.g. MegsonAbstract:The method for the determination of the shear stress distribution in the walls of a thin-walled Closed Section Beam is described as is the determination of the twisting and warping displacements. The nature of the warping displacements in the walls of a thin-walled rectangular Section box is discussed and the condition for the zero warping of a Beam Section established. Expressions for the stress distributions, the rate of twist and the warping displacements in a thin-walled open Section Beam are also derived.
-
Closed Section Beams
Aircraft Structures for Engineering Students, 2013Co-Authors: T.h.g. MegsonAbstract:Publisher Summary This chapter examines some relatively simple examples of determination of stresses and displacements produced by axial loads, shear forces and bending moments, and torsion effects. More complex cases require analysis by computer-based techniques such as the finite element method. Structural constraint stresses in either Closed or open Beams result from a restriction on the freedom of any Section of the Beam to assume its normal displaced shape under load. Such a restriction arises when one end of the Beam is built-in, although the same effect may be produced practically, in a variety of ways. This special case of structural constraint is of interest because the shear stress distribution at the built-in end of a Closed Section Beam is statically determinate. The chapter discusses thin-walled rectangular Section Beam subjected to torsion. A problem closely related to the restrained torsion of rectangular Section Beams is generally known as shear lag. The chapter ends with a discussion of this shear lag.
-
Shear of Beams
Aircraft Structures for Engineering Students, 2013Co-Authors: T.h.g. MegsonAbstract:Publisher Summary This chapter establishes the equations of equilibrium and expressions for strain necessary for the analysis of open Section Beams supporting shear loads and Closed Section Beams carrying shear and torsional loads. It discusses the general stress, strain, and displacement relationships for open and single-cell Closed Section thin-walled Beams. The chapter defines the position of the shear center as the point in the cross-Section through which shear loads produce no twisting. It may be shown by use of the reciprocal theorem that this point is also the center of twist of the Sections subjected to torsion. There are, however, some important exceptions to this general rule. Clearly, in the majority of practical cases, it is impossible to guarantee that a shear load will act through the shear center of a Section. Equally apparent is the fact that any shear load may be represented by the combination of the shear load applied through the shear center and a torque. The stresses produced by the separate actions of torsion and shear then may be added by superposition. It is, therefore, necessary to know the location of the shear center in all types of Section or to calculate its position. The chapter describes that the solution for a shear loaded Closed Section Beam follows a similar pattern to that described for an open Section Beam but with two important differences. First, the shear loads may be applied through points in the cross-Section other than the shear center, so that torsional effects, as well as shear effects, are included.
-
Chapter 17 – Torsion of Beams
2010Co-Authors: T.h.g. MegsonAbstract:The method for the determination of the shear stress distribution in the walls of a thin-walled Closed Section Beam is described as is the determination of the twisting and warping displacements. The nature of the warping displacements in the walls of a thin-walled rectangular Section box is discussed and the condition for the zero warping of a Beam Section established. Expressions for the stress distributions, the rate of twist and the warping displacements in a thin-walled open Section Beam are also derived.
-
Chapter 11 – Torsion of Beams
Structural and Stress Analysis, 2005Co-Authors: T.h.g. MegsonAbstract:Publisher Summary Torsion in Beams arises generally from the action of shear loads, whose points of application do not coincide with the shear center of the Beam Section. The solution of torsion problems is complex particularly in the case of Beams of solid Section and arbitrary shape for which exact solutions do not exist. Empirical formulae are used that are conveniently expressed in terms of correction factors based on the geometry of a particular shape of cross Section. The behavior of Closed and open Section Beams under torsional loads is similar, in that they twist and develop internal shear stress systems. A pure torque applied to a Beam Section produces a Closed, continuous shear stress system because the resultant of any other shear stress system would generally be a shear force unless the system was self-equilibrating. In a Closed Section Beam the Closed loop system of shear stresses is allowed to develop in a continuous path round the cross Section, whereas in an open Section Beam it can only develop within the thickness of the walls.
Yongsheng Ren - One of the best experts on this subject based on the ideXlab platform.
-
Vibration and flutter of wind turbine blade modeled as anisotropic thin-walled Closed-Section Beam
Science China Technological Sciences, 2011Co-Authors: Tingrui Liu, Yongsheng RenAbstract:Based on a variational asymptotic analytical model, vibration and aeroelastic stability of rotor blades modeled as anisotropic thin-walled Closed-Section Beams are systematically addressed. The analysis is applied to a laminated composite construction of the circumferentially asymmetric stiffness (CAS) that produces bending-twist coupling. The vibration characteristics of composite Beam are determined by the Extended Galerkin Method. The unsteady aerodynamic loads and centrifugal force are integrated with the classical aerodynamic model to deal with aeroelastic stability analysis. The influence of some related factors, ply angle, rotating velocity, and wind speed, is investigated. The paper gives methods of eigenvalue analysis and aeroelastic response, and gives the approaches to restrain classical flutter.
Eric R. Johnson - One of the best experts on this subject based on the ideXlab platform.
-
Cross-Sectional Analysis of Anisotropic, Thin-Walled, Closed-Section Beams with Embedded Strain Actuation
46th AIAA ASME ASCE AHS ASC Structures Structural Dynamics and Materials Conference, 2005Co-Authors: Mayuresh J. Patil, Eric R. JohnsonAbstract:The paper presents a theory for the analysis of active anisotropic Beams. The focus of the paper is on the calculation of 2-D, Beam, cross-Sectional properties that can then be incorporated into any 1-D Beam analysis. Closed-form expressions for the cross-Section flexibilities as well as actuation strains for an active, anisotropic, thin-walled, Closed-Section Beam are derived and presented in a form that can be easily applied. Test cases presented in the paper indicate that the theory can be used to eciently calculate accurate crossSectional properties for preliminary design and optimization.
Tingrui Liu - One of the best experts on this subject based on the ideXlab platform.
-
Vibration and flutter of wind turbine blade modeled as anisotropic thin-walled Closed-Section Beam
Science China Technological Sciences, 2011Co-Authors: Tingrui Liu, Yongsheng RenAbstract:Based on a variational asymptotic analytical model, vibration and aeroelastic stability of rotor blades modeled as anisotropic thin-walled Closed-Section Beams are systematically addressed. The analysis is applied to a laminated composite construction of the circumferentially asymmetric stiffness (CAS) that produces bending-twist coupling. The vibration characteristics of composite Beam are determined by the Extended Galerkin Method. The unsteady aerodynamic loads and centrifugal force are integrated with the classical aerodynamic model to deal with aeroelastic stability analysis. The influence of some related factors, ply angle, rotating velocity, and wind speed, is investigated. The paper gives methods of eigenvalue analysis and aeroelastic response, and gives the approaches to restrain classical flutter.
Yang Shulian - One of the best experts on this subject based on the ideXlab platform.
-
Aeroelastic Stability Analysis of Composite Wind Turbine Blade Dynamic Stall
Journal of Mechanical Engineering, 2011Co-Authors: Yang ShulianAbstract:A nonlinear aeroelastic analysis model of the composite wind turbine blade is presented.The composite structural model is an anisotropic thin-walled Closed-Section Beam with bending-twist coupling produced by a special ply-angle configuration,referred to as circumferentially asymmetric stiffness(CAS).The aerodynamic model used in the present paper is the differential dynamic stall model developed at ONERA.By means of Galerkin's method,the nonlinear aeroelastic equations are reduced to ordinary equations.The general aerodynamic forces are obtained from strip theory.The resulting equations are then linearized for small perturbation about the equilibrium point and the stability characteristics are investigated through eigenvalue analysis and time domain integration.