Methods of modeling slope discontinuities in large size wind turbine blades using absolute nodal coordinate formulation

Bayoumy, Ahmed H.; Nada, Ayman A.; Megahed, Saïd M.

doi:10.1177/1464419314528319

Cited by 4 publications

(3 citation statements)

References 21 publications

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“…These elements have been widely used in the nonlinear analysis of a wide range of challenging applications, some of which have complex geometry. 38…”

Section: Ancf Mesh Topologymentioning

confidence: 99%

Mechanically induced temperature oscillations in the coupled thermo-elasticity analysis of articulated dynamical systems

Shabana

2023

Proceedings of the Institution of Mechanical Engineers, Part K:

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This article discusses a new approach for predicting and quantifying mechanically induced temperature oscillations in the coupled thermo-elasticity analysis of articulated mechanical systems (AMS). In this approach, the constrained equations of motion are solved simultaneously with discrete temperature equations obtained by converting heat partial-differential equation to a set of first-order ordinary differential equations. Dependence of the temperature gradients and their spatial derivatives on the position gradients, spinning motion, and curvatures is discussed. The approach captures dependence of the temperature-oscillation frequencies on the mechanical-displacement frequencies. The temperature field can be selected to ensure continuity of the temperature gradients at the nodal points. To generalize the AMS coupled thermo-elasticity formulation and capture the effect of the boundary and motion constraints (BMC) on the thermal expansion, the proposed method is based on integrating thermodynamics and Lagrange-D’Alembert principles. The absolute nodal coordinate formulation (ANCF) is used to describe continuum displacement and obtain accurate description of the reference-configuration geometry and change of this geometry due to deformations. A thermal-analysis large-displacement formulation is used to allow converting heat energy to kinetic energy, ensuring stress-free thermal expansion in case of unconstrained uniform thermal expansion. Cholesky heat coordinates are used to define an identity coefficient matrix for the efficient solution of the discretized heat equations. The approach presented is applicable to the two different forms of the heat equation used in the literature; one form is explicit function of the stresses while the other form does not depend explicitly on the stresses. Because of the need for using ANCF finite elements to achieve a higher degree of continuity in the coupled thermomechanical approach introduced in this article, the concept of the ANCF mesh topology is discussed.

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“…These elements have been widely used in the nonlinear analysis of a wide range of challenging applications, some of which have complex geometry. 38…”

Section: Ancf Mesh Topologymentioning

confidence: 99%

Mechanically induced temperature oscillations in the coupled thermo-elasticity analysis of articulated dynamical systems

Shabana

2023

Proceedings of the Institution of Mechanical Engineers, Part K:

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“…Under the umbrella of the multibody system dynamics, efficient procedure was developed for mapping airfoils geometry of wind turbine blades into flexible models using absolute nodal coordinate formulation (ANCF) [4,5]. This procedure is extended to involve the complete aerodynamical and structural behavior of blades with the nonuniform and twisted configuration [6]. The effectiveness of using ANCF in modeling large-size wind turbine blades is examined through dynamic/static simulation procedure, and a method for designing such blades within DFD process is introduced successfully for practical wind conditions [7].…”

Section: Introductionmentioning

confidence: 99%

Computational Design Scheme for Wind Turbine Drive-Train Based on Lagrange Multipliers

et al. 2017

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The design optimization of wind turbines and their subsystems will make them competitive as an ideal alternative for energy. This paper proposed a design procedure for one of these subsystems, which is the Wind Turbine Drive-Train (WTDT). The design of the WTDT is based on the load assumptions and considered as the most significant parameter for increasing the efficiency of energy generation. In industry, these loads are supplemented by expert assumptions and manipulated to design the transmission elements. In contrary, in this work, the multibody system approach is used to estimate the static as well as dynamic loads based on the Lagrange multipliers. Lagrange multipliers are numerical parameters associated with the holonomic and nonholonomic constraints assigned in the drive-train model. The proposed scheme includes computational manipulations of kinematic constraints, mapping the generalized forces into Cartesian respective, and enactment of velocity-based constrains. Based on the dynamic model and the obtained forces, the design process of a planetary stage of WTDT is implemented with trade-off’s optimization in terms of gearing parameters. A wind turbine of 1.4 megawatts is introduced as an evaluation study of the proposed procedure, in which the main advantage is the systematic nature of designing complex systems in motion.

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“…Numerical results can be compared to: measured values of a real engineering application [21], measured values of a custom-designed experimental setup [22] or to another…”

Section: Introductionmentioning

confidence: 99%

Absolute Nodal Coordinate Formulation in a Pre-Stressed Large-Displacements Dynamical System

Skrinjar

Slavič

Boltežar

2017

Stroj. vest. - Jour. Mech. Eng.

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The design process for dynamical models has to consider all the properties of a mechanical system that have an effect on its dynamical response. In multi-body dynamics, flexible bodies are frequently modeled as rigid, resulting in non-valid Keywords: ANCF, pre-stress, multibody system, measurement Highlights • A numerical model of a rigid-flexible multibody system is used in the analysis of kinematic properties during switch-off. • A flexible body is modeled with the Absolute Nodal Coordinate Formulation to include the pre-stress effect. • The influence of different parameters on the switch-off time and the contact distance is investigated. • The numerical model was validated and shows good agreement with the experimental values. INTRODUCTIONWhen modeling dynamical systems the proper material and contact properties of the numerical model are crucial for simulating an accurate dynamic response. One of the properties to be considered is the effect of pre-stress on rigid and flexible bodies, as it can have a significant impact on the dynamical response of multibody mechanical systems.The modeling of deformable bodies in a multibody system can be done using a floating frame of reference (FFR) [1], which is based on the classic finite element (FE) method that is widely used in a variety of applications [2] and [3]. While in a floating frame of reference formulation a mixed set of absolute reference and local elastic coordinates are used, in the absolute nodal coordinate formulation (ANCF) only absolute coordinates are used, which include global displacement and global vector gradients [4]. The ANCF is a non-incremental method and it has been used for solving many different problems in mechanics, such as vehicle components [5] and [6], the modeling of belt drives [7], railroad applications [8], bio-mechanics [9] and also in the field of digital image correlation (DIC) [10]. The main features of the ANCF are a constant mass matrix, zero centrifugal and Coriolis inertia forces and the possibility for exact modeling of rigid-body movement.The modeling of the pre-stress effect on bodies in mechanical systems is an interesting research topic in civil-engineering applications [11], where the static [12] and dynamic responses of structural elements are considered [13]. The effect of pre-stress is introduced to the ANCF finite elements to create an accurate model of a leaf spring, where pre-stress is evaluated based on the known geometrical states in the undeformed and deformed configurations that define the vector of absolute nodal coordinates [14]. In [15] the effect of the non-dimensional axial pre-stress of eigenfrequencies on a simply supported beam is researched. The pre-stress effect is included in the model of a flexible multibody belt-drive [16], where the belt-drive is modeled with ANCF two-dimensional shear deformable beam elements that account for the longitudinal and shear deformations.When modeling mechanical systems [17-20] a validation is needed to evaluate the results from the numerical model, this can be ...

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Methods of modeling slope discontinuities in large size wind turbine blades using absolute nodal coordinate formulation

Cited by 4 publications

References 21 publications

Mechanically induced temperature oscillations in the coupled thermo-elasticity analysis of articulated dynamical systems

Mechanically induced temperature oscillations in the coupled thermo-elasticity analysis of articulated dynamical systems

Computational Design Scheme for Wind Turbine Drive-Train Based on Lagrange Multipliers

Absolute Nodal Coordinate Formulation in a Pre-Stressed Large-Displacements Dynamical System

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