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

On meshless and nodal-based numerical methods for forming processes

Currently, the main tool for the simulation of forming processes is the finite element method. Unfortunately, for processes involving very large deformations, finite elements based on a Lagrangian formulation are problematic due to mesh distortion. Results become inaccurate and might even lose their physical meaning.\ud \ud In the 1980s, a new group of numerical methods emerged. This group is entitled meshless methods, and aims at avoiding problems related to the use of a mesh. The nodal-based approach of these methods does not restrict the relative motion of nodes by shape criteria related to elements. The goal of the research as presented in this thesis is to develop a meshless method for solving large deformations more efficiently than currently possible with finite elements.\ud \ud The first step in this research was to select a single meshless method for further developments. Therefore, three meshless shape functions and two numerical integration schemes were investigated in a comparative study. It can be concluded that diffuse meshless shape functions, like moving least squares and local maximum entropy approximations, are more accurate than simple linear interpolation upon a Delaunay triangle. However, the computational effort for these two diffuse functions is considerably higher. Concerning the numerical integration, a nodal integration scheme performs very well. Volumetric locking is absent and good accuracy is obtained.\ud \ud Therefore the linear triangle interpolation in combination with a nodal integration scheme was chosen for further development. For this combination, an extension to large deformations was presented. The new method, named Adaptive Smoothed Finite Elements (ASFEM), is based on a cloud of nodes following a Lagrangian description of motion and a triangulation algorithm that sets up the connectivity between nodes for each increment. The method was successfully tested on the simulation of a forging process and an extrusion process. No failure of the algorithm as a result of mesh distortion was encountered. Results compared accurately to reference solutions made with finite elements

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

The EU and its Member States’ Trade Support Programmes for Economic Partnership Agreements (EPAs)

Trade is prominently mainstreamed into development policies and the Economic Partnership Agreements (EPAs) between the EU and the African, Caribbean and Pacific (ACP) Group of countries opened a new trade and development chapter based on reciprocity. However, during the negotiations many Least Development Countries (LDCs) and some non-LDCs like Nigeria refused to sign an EPA, jeopardising the EU’s objective of regional comprehensive trade agreements. At the moment there is only one comprehensive EPA with the Caribbean region (CARIFORUM), while in Africa there are agreements in West Africa, East Africa and Southern Africa, however, within each region individual countries that have opted out from signing it. Most ACP countries fear lifting barriers to European imports as that will place pressure on the agricultural and manufacturing sectors, diverting their diversification efforts that could make them economically dependent on a limited amount of export commodities. Hence, development cooperation was always an important part of the negotiations strategy to improve supply-side competitiveness; business enhancing infrastructure; trade data; EPA institutional capacity building; and fiscal adjustment. The West African region (ECOWAS) is the only region that succeeded to negotiate EUR 6.5 billion from the EU for its EPA Development Programme (EPADP for the first phase of West Africa’s EPA implementation till 2020. The South Africa region (SADC-minus) is working on its own EPA development fund, but without the EU putting a number on the EPA support contribution. The strategy of the EU is to reaffirm that EPA related trade and development cooperation will be facilitated by existing aid mechanisms linked to the Cotonou Agreement and the European Development Fund (EDF). The most important channels for support and assistance for EPAs comes through: EU Aid for Trade, EU External Investment Plan, EDF Regional and National Indicative Programmes and its ACP Trade and Private Sector Development (PSD) programmes. There are three institutions within the EU that provide the main support/assistance for EPAs: EC International Cooperation and Development via its European Development Fund; European Investment Bank; and EU member states. The Commission has pledged to commit approximately half of its annual €2 billion Aid for Trade (AfT) contribution to support ACP countries, largely though not exclusively through EPA implementation projects. AfT commitments in two categories (trade related infrastructure and building productive capacity) represented more than 97% of total EU AfT commitments in 2015. The largest remained “trade related infrastructure”, with EUR 6.6 billion of commitments (trade-related physical infrastructures including transport, storage, communication and energy generation and supply), while “building productive capacity” remained the second largest category, with EUR 6.2 billion. The EU trade and development support evolved from being linked with WTO rules to being linked to bilateral Free Trade Agreements (FTAs), like EPAs and regional economic integration processes. Another trend that can be seen in the literature and online resources is that trade and development support is becoming less technical and shifts towards trade facilitation, PSD and Investment. Over the last 8 years the EU includes more ODA loans from the European Investment Bank (EIB) to their total trade and development support. Although hard infrastructure, like ports and road construction, remain important investments, there is also a new focus on digital connectivity and the importance of investments in online environments. Looking at the EU member states, France and Germany increasingly focus on the investment side of trade support by providing loans, while the Netherlands, United Kingdom, Sweden, Belgium and Denmark are more focussing on ODA grants. The literature also shows that trade assistance and other trade related support impact positively on improving trade conditions, lowering trade costs and the integration of developing countries in the global trade system. What this means for poverty reduction, gender issues and income inequality is highly debatable in the literature. This report not only gives an introduction to the state of affairs and channels of which trade related development support is given to ACP countries related to EPAs, it also gives an overview of what kind of support is given per region in Appendix 2. This list does not claim to be extensive, but is an indication for what happened during the last 5 years. What will happen after 2020 is not clear with Brexit negotiations, EU negotiations on the future of the Cotonou agreement (and the future existence of the ACP Group of countries), and the EU negotiations on a new budget for 2020-2027 all happening at the same time