Nodal integration of meshless methods

Meshless methods offer interesting properties for the simulation of bulk forming\ud processes. This research concerns the investigation of the stabilized conforming nodal integration scheme (SCNI) for use in metal-forming processes. Two tests are carried out. Firstly, the performance of SCNI is compared to a standard integration scheme. The performance seems problem specific. Secondly the footing of a piece of nearly incompressible material is used for testing the locking behavior of the method. No volumetric locking was found

Adaptive smoothed FEM for forming simulations

FEMsimulation of large deformations as occur in metal forming processes is usually accompanied with highly distorted meshes. This leads first to a reduction of accuracy and later to loss of convergence when implicit solvers are used. Remeshing can be used to reduce element distortion, but repeated remeshing will result in smoothing of data like equivalent plastic strain, due to averaging and interpolation. A meshless method circumvents the problem of mesh distortion, but depending on the integration of the weak formulation of equilibrium mapping of data and hence smoothing of data still remains unless a\ud nodal integration scheme is used. Starting with a LocalMaximum Entropy approach [1] with nodal integration, we end-up with a smoothed Finite Element formulation in the limit of local approximations [2]. It is straightforward to adapt the triangulation in every increment, yielding an Adaptive Smoothed Finite\ud Element Method, in which large deformations can be modelled with a Lagrangian description without the necessity to map data from one step to the other.\ud A cell based stabilized conforming nodal integration method (SCNI) [3] is used. Depending on the configuration of nodes, nodal integration can yield singular stiffness matrices, resulting in spurious displacement modes [4]. A stabilization is used, based on minimizing the difference between a ‘linear\ud assumed’ and the consistent strain field. The cells are based on the Delaunay triangulation, connecting mid-sides and centres of gravity of the triangles (Figure 1). Especially at the outer boundary, this yields a simpler formulation than using the dual Voronoi tesselatio

Urban Distribution: The Impacts of Different Governmental Time-Window Schemes

Local authorities increasingly use time-access regulations to improve social sustainability issues, such as the attractiveness of a city centre, the shopping climate, or to reduce the nuisance caused by urban freight transport. However, these time-windows increase delivery costs and the environmental burden. This paper evaluates five different time-window schemes on their social, environmental, and economic impacts. The first scheme examines the current time-window policy scheme. In the second scheme time-windows are harmonized between different cities. The third scheme moves all deliveries to the night. The fourth and fifth schemes evaluate the consequences of the proposal by the Dutch committee for urban distribution (committee Sakkers). The fourth scheme includes noise-legislation for delivering during the night, the fifth does not. This research includes interviews with several Dutch policy-making officials and is further based on a multiple-case study of fourteen large retail chains in different sectors and with different formulas. The results show that the current time-window scheme performs worst. The best time-window scheme would be a combination of the proposal of the committee Sakkers and the harmonization scenario.City Logistics;Retail Logistics;Sustainability;Time-Window Regulation;Urban Goods Movement

Modeling emergency management data by UML as an extension of geographic data sharing model: AST approach

Applying GIS functionality provides a powerful decision support in various application areas and the basis to integrate policies directed to citizens, business, and governments. The focus is changing toward integrating these functions to find optimal solutions to complex problems. As an integral part of this approach, geographic data sharing model for Turkey were developed as a new approach that enables using the data corporately and effectively. General features of this model are object-oriented model, based on ISO/TC211 standards and INSPIRE Data Specifications, describing nationwide unique object identifiers, and defining a mechanism to manage object changes through time. The model is fully described with Unified Modeling Language (UML) class diagram. This can be a starting point for geographic data providers in Turkey to create sector models like Emergency Management that has importance because of the increasing number of natural and man-made disasters. In emergency management, this sector model can provide the most appropriate data to many "Actors" that behave as emergency response organizations such as fire and medical departments. Actors work in "Sectors" such as fire department and urban security. Each sector is responsible for "Activities" such as traffic control, fighting dire, emission, and so on. "Tasks" such as registering incident, fire response, and evacuating area are performed by actors and part of activity. These tasks produce information for emergency response and require information based on the base data model. By this way, geographic data models of emergency response are designed and discussed with "Actor-Sector-Activity-Task" classes as an extension of the base model with some cases from Turkey

Transnational Firms and their Corporate Labor Policy: Case Studies on Philips and ING in the Netherlands and the United States, 1980–2010

In the last quarter of the 20th century, many firms significantly expanded their operations across national borders. It has been argued that, as a result, they have become disembedded from the national economic fields in which they conduct their business and have experienced a race to the bottom in their corporate labor policy. This dissertation argues that this contention does not accurately describe the recent development of transnational firms and their corporate labor policy. Rather, transnational firms experienced a significant shift in their dual embeddedness in national and transnational economic fields. They were restructured in line with the competitive conditions in the transnational economic field, but the competitive conditions in the national economic fields continue to be of great importance for their corporate labor policy. Consequently, the recent development of their corporate labor policy is characterized by processes of centralization, instrumentalization, and polarization

On the use of local max-ent shape functions for the simulation of forming processes

In this work we review the opportunities given by the use of local maximum-\ud entropy approximants (LME) for the simulation of forming processes. This approximation can\ud be considered as a meshless approximation scheme, and thus presents some appealing features\ud for the numerical simulation of forming processes in a Galerkin framework.\ud Especially the behavior of these shape functions at the boundary is interesting. At nodes\ud on the boundary, the functions possess a weak Kronecker-delta property, hence simplifying the\ud prescription of boundary conditions. Shape functions at the boundary do not overlap internal\ud nodes, nor do internal shape functions overlap nodes at the boundary. Boundary integrals can be\ud computed easily and efficiently compared to for instance moving least-squares approximations.\ud Furthermore, LME shapes also present a controllable degree of smoothness.\ud To test the performance of the LME shapes, an elastic and a elasto-plastic problem was\ud analyzed. The results were compared with a meshless method based on a moving least-squares\ud approximation

Exploring retailers' sensitivity to local sustainability policies

Local governments in Western Europe increasingly use city time-access regulations to improve social sustainibility. These regulations significantly influence the distribution process of retail chain organizations. This paper studies the impact of governmental timewindow pressure on retailers’ logistical concept and consequential financial and environmental distribution performance. We determine which dimensions in the retailer’s logistical concept determine its cost and emission sensitivity to increasing time-win

Urban Distribution: The Impacts of Different Governmental Time-Window Schemes

Local authorities increasingly use time-access regulations to improve social sustainability issues, such as the attractiveness of a city centre, the shopping climate, or to reduce the nuisance caused by urban freight transport. However, these time-windows increase delivery costs and the environmental burden. This paper evaluates five different time-window schemes on their social, environmental, and economic impacts. The first scheme examines the current time-window policy scheme.