Global Local Framework Research Articles

A global–local discontinuous Galerkin finite element for finite-deformation analysis of multilayered shells

We present a global–local finite element formulation for the analysis of doubly-curved laminated composite shells. The proposed formulation is applicable to a wide range of problems, including those involving finite strains/rotations, nonlinear constitutive behavior, and static or dynamic structural response. Moreover, in dynamic analysis applications, it can be combined with either explicit or implicit time integration schemes. The global–local framework is based on the superposition of a global displacement field, spanning the thickness of the entire laminate, and local (i.e. layerwise) displacement fields associated with each layer in the laminate. This approach affords highly-resolved representations in regions of critical interest, and allows a smooth transition from higher to lower resolution zones. Discontinuous Galerkin fluxes are used to enforce interlaminar continuity conditions in perfectly-bonded laminates, and the cohesive-zone methodology is used to represent interfacial delamination. Stresses and surface normals are referred to the initial configuration in the proposed total Lagrangian formulation. Assumed natural strain and enhanced assumed strain techniques are employed to alleviate shear locking and other pathologies that are known to afflict bilinear shell elements. The performance of the proposed finite element is examined with the aid of several numerical examples involving thick as well as thin shells.

A global–local discontinuous Galerkin shell finite element for small-deformation analysis of multi-layered composites

This paper focuses on the development of a global–local doubly-curved shell element, suitable for small-deformation implicit and/or explicit dynamic analysis of laminated composite structures. The global–local framework is based on the superposition of a global displacement field, spanning the thickness of the entire laminate, and local (layerwise) displacement fields associated with each layer of the laminate. This approach affords highly-resolved representations in regions of critical interest, and allows a smooth transition from higher to lower resolution zones. Continuity between adjacent layers is enforced by means of discontinuous Galerkin fluxes. Parasitic phenomena characteristic of bilinear shell elements, such as shear locking, are alleviated with the aid of assumed natural strain techniques. Performance characteristics of the proposed finite element are examined with the aid of several numerical examples involving static and dynamic analysis of thick as well as thin shells.

Overview: Restructuring Chinese space in the new millennium

This collection is concerned with understanding the nature of China’s spatial development during the transition to a socialist market economy. It does so primarily by questioning the applicability of the ‘desakota’ model and extended metropolitan region (EMR) concept to the contemporary Chinese space economy. Yu Zhu’s contribution extends the ‘desakota’ model by applying it to rural areas without the attraction of large cities. Wing‐Shing Tang and Him Chung’s contribution discusses illegal land use and construction to highlight the rural‐urban transition’s negative and disintegrative aspects glossed over by the ‘desakota’ model, which stem from the extension of urban administration to former rural areas and the redistributive effects of land use reform. Andrew Marton sees the original ‘desakota’ model being rejuvenated by introducing the notion of rural agglomeration, a clearer recognition of local administrative structures and an appreciation that development issues now take place within a global‐local framework. George Lin explores the lingering effects of rural origins on Chinese identity and how this affects subsequent social and commercial groups within the Chinese diaspora. Peter Rimmer and Claude Comtois show how changes in China’s transport and telecommunications industry underlie, to a significant degree, the restructuring of China’s space economy and the country’s links to the rest of the world. Overall the contributions highlight that a new consensus will be required for any revised model of the Chinese space economy if this is to provide guidance for planners engaged in restructuring Chinese space in the new millennium.