Topic
Bending moment
About: Bending moment is a research topic. Over the lifetime, 14577 publications have been published within this topic receiving 158834 citations. The topic is also known as: bending moment.
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16 Oct 2018
TL;DR: In this paper, a model for quick load analysis of floating wind turbines (QuLAF) is presented and validated, which relies on state-of-the-art tools from which hydrodynamic, aerodynamic and mooring loads are extracted and cascaded into QuLAF.
Abstract: . A model for Quick Load Analysis of Floating wind turbines (QuLAF) is
presented and validated here. The model is a linear, frequency-domain,
efficient tool with four planar degrees of freedom: floater surge, heave,
pitch and first tower modal deflection. The model relies on state-of-the-art
tools from which hydrodynamic, aerodynamic and mooring loads are extracted
and cascaded into QuLAF. Hydrodynamic and aerodynamic loads are pre-computed
in WAMIT and FAST, respectively, while the mooring system is linearized
around the equilibrium position for each wind speed using MoorDyn. An
approximate approach to viscous hydrodynamic damping is developed, and the
aerodynamic damping is extracted from decay tests specific for each degree of
freedom. Without any calibration, the model predicts the motions of the
system in stochastic wind and waves with good accuracy when compared to FAST.
The damage-equivalent bending moment at the tower base is estimated with
errors between 0.2 % and 11.3 % for all the load cases
considered. The largest errors are associated with the most severe wave
climates for wave-only conditions and with turbine operation around rated
wind speed for combined wind and waves. The computational speed of the model
is between 1300 and 2700 times faster than real time.
45 citations
TL;DR: In this article, theoretical natural frequencies and mode shapes of the first four coupled modes of a uniform pretwisted cantilever blade and the first five coupled flexural frequencies of pre-tended tapered blading are determined by using the Reissner method.
45 citations
TL;DR: In this article, a non-traditional approach to the basic components of the traditional viscoelastic models, such as spring and damper, has been proposed for the back-relaxation of ionic electroactive polymer actuators.
Abstract: The mechanical model obtained by a non-traditional approach to the basic components of the traditional viscoelastic models—spring and damper—elucidates the back-relaxation of ionic electroactive polymer actuators. The corresponding PDE characterizes the curvature or bending moment of the actuators throughout stimulated bending forward followed by relaxation back towards the initial shape. Combining series of short entities containing the lumped electrical circuit, and the transient bending moment generated according to the PDE, results in a new model of the ionic electroactive polymer actuators. This model takes into account the back-relaxation of the actuators as well as the superposition principle. The experiments carried out with three actuators of different ionic electroactive polymer materials show excellent accordance with the model.
44 citations
TL;DR: In this article, a nonlocal finite element method (NFEM) is consistently developed to evaluate the displacement and the bending moment of nanobeams, based on a high-order Euler-Bernoulli nonlocal beam theory.
Abstract: Based on a high-order Euler–Bernoulli nonlocal beam theory, a nonlocal finite element method (NFEM) is consistently developed to evaluate the displacement and the bending moment of nanobeams. As a benchmark a simply supported nanobeam under a uniform external load is considered and the numerical solution obtained by means of the proposed NFEM is compared with the exact nonlocal solution obtained by solving a sixth-order differential equation. The comparison shows that the NFEM provides an exact solution of the nonlocal problem, for any value of the internal length parameter, with a coarse mesh. The proposed NFEM does not show pathological behaviours such as mesh dependence, numerical instability or boundary effects. Moreover a cantilever nanobeam subjected to an intermediate applied force is addressed. Contrary to what is reported in the literature, the proposed methodology shows that the nonlocal effects are apparent to both left and right of the application point of the external force.
44 citations
TL;DR: In this paper, the effect of brace end rotation on the global stability of buckling-restrained braces (BRBs) is investigated, and a simplified procedure to estimate the magnitudes of end bending moments is proposed.
44 citations