The aim of this study is to provide a comprehensive review of the finite element absolute nodal coordinate formulation, which can be used to obtain efficient solutions to large deformation problems of constrained multibody systems. In particular, important features of different types of beam and plate elements that have been proposed since 1996 are reviewed. These elements are categorized by parameterization of the elements (i.e., fully parameterized and gradient deficient elements), strain measures used, and remedies for locking effects. Material nonlinearities and the integration of the absolute nodal coordinate formulation to general multibody dynamics computer algorithms are addressed with particular emphasis on visco-elasticity, elasto-plasticity, and joint constraint formulations. Furthermore, it is shown that the absolute nodal coordinate formulation has been applied to a wide variety of challenging nonlinear dynamics problems that include belt drives, rotor blades, elastic cables, leaf springs, and tires. Unresolved issues and future perspectives of the study of the absolute nodal coordinate formulation are also addressed in this investigation.

This study proposes a dynamic model of a deep-groove ball bearing with six degrees of freedom. The model includes descriptions of non-linear Hertzian contact deformation and elastohydrodynamic (EHD) fluid film. The geometry, material properties and diametral clearance of the bearing are given as the input to the proposed model. The bearing force and torque components are calculated from the relative displacements and velocities between bearing rings. Distributed defects, such as the waviness of the inner and outer ring, and localized defects, such as inner and outer ring defects, are taken into consideration in the proposed model. The proposed ball bearing model could be used in the general multi-body or rotor dynamics computer code as an interference element between the rotor and the housing. The numerical results obtained from the model are compared with those found in the literature in Part 2 of this paper.

Wind turbines are getting larger. Their rated power capacities are moving from the 3 MW range to 6 MW and beyond. As a result, their size and mass, which grow rapidly with power capacity, is becoming a problem in terms of capital cost, logistics and assembly. Moreover, there is a move to offshore installations. Offshore wind turbines demand higher reliability, encouraging wind turbine manufacturers to integrate into their new designs inherently more reliable direct-drive permanent magnet synchronous generators. However, today's high-power direct-drive generators are massive units that will need to become smaller to minimise costs. Here, the authors review the technological and economic benefits and limitations of direct-drive permanent magnet synchronous generators (DD-PMSGs). The authors examine the benefits and the physical and economic limitations of DD-PMSGs and consider their appropriateness as a key piece in the overall wind turbine system design. The authors look at why these generators are so big and propose a change that can lead to a more compact, more economical wind turbine nacelle.