S.M. Afazov

Development of a Finite Element Data Exchange System for chain simulation of manufacturing processes

A Finite Element Data Exchange System (FEDES) is developed to transfer and map finite element analysis (FEA) data between different FE solvers and meshes. Six commercial FE codes (ABAQUS, ANSYS, DEFORM, MSC.MARC, MORFEO and VULCAN) are incorporated in FEDES. Four mapping techniques are developed and embedded in FEDES which allow the data mapping between meshes with different element types and densities. The algorithms of the mapping techniques are described and compared for 2D and 3D models. The design and capabilities of FEDES are also described. Results from the data transfer and mapping between different FE simulations are presented and discussed. Two manufacturing chains are simulated using FEDES in this paper. The first manufacturing chain is simulated on a parallelepiped geometry including casting, forging and heat treatment processes. The second manufacturing chain is simulated on an aero-engine vane component including metal deposition, welding, heat treatment, machining and shot-peening processes. The development of FEDES demonstrates an integrated simulation platform for modelling manufacturing chains of processes using different FE solvers and meshes.

Modelling aspects of the design of railway vehicle structures and their crashworthiness

Travelling by rail is considered to be a safe option compared with other types of transport, in terms of the number of accidents. However, there are always opportunities to improve the current safety standards and industrial practices. The aim of this paper is to give a better understanding of the current modelling techniques that could support the design of new railway vehicle structures. The paper highlights the established practices in modelling of proof, fatigue and crashworthiness. It also reviews the state-of-the-art in the modelling of material behaviour, recommends practical modelling solutions that can be used in the railway industry, and demonstrates new modelling techniques for crashworthiness.

An in-core grid index for transferring finite element data across dissimilar meshes

An indexing technique for mapping finite element data is presented.The underlying space of an indexed mesh is decomposed into variable-sized cells.Creation of an index and search for nodes and elements are fast.An experimental evaluation of mapping techniques using the index is conducted.The algorithms have been implemented in FEDES (Finite Element Data Exchange System). The simulation of a manufacturing process chain with the finite element method requires the selection of an appropriate finite element solver, element type and mesh density for each process of the chain. When the simulation results of one step are needed in a subsequent one, they have to be interpolated and transferred to another model. This paper presents an in-core grid index that can be created on a mesh represented by a list of nodes/elements. Finite element data can thus be transferred across different models in a process chain by mapping nodes or elements in indexed meshes. For each nodal or integration point of the target mesh, the index on the source mesh is searched for a specific node or element satisfying certain conditions, based on the mapping method. The underlying space of an indexed mesh is decomposed into a grid of variable-sized cells. The index allows local searches to be performed in a small subset of the cells, instead of linear searches in the entire mesh which are computationally expensive. This work focuses on the implementation and computational efficiency of indexing, searching and mapping. An experimental evaluation on medium-sized meshes suggests that the combination of index creation and mapping using the index is much faster than mapping through sequential searches.

Fast mapping of finite element field variables between meshes with different densities and element types

In the simulation of a chain of manufacturing processes, several finite element packages can be employed and for each process or package a different mesh density or element type may be the most suitable. Therefore, there is a need for transferring finite element analysis (FEA) data among packages and mapping it between meshes. This paper presents efficient algorithms for mapping FEA data between meshes with different densities and element types. An in-core spatial index is created on the mesh from which FEA data is transferred. The index is represented by a dynamic grid partitioning the underlying space from which nodes and elements are drawn into equal-sized cells. Buckets containing references to the nodes indexed are associated with the cells in a many-to-one correspondence. Such an index makes nearest neighbour searches of nodes and elements much faster than sequential scans. An experimental evaluation of the mapping techniques using the index is conducted. The algorithms have been implemented in the open source finite element data exchange system FEDES.

Effects of the Cutting Tool Edge Radius on the Stability Lobes in Micro-Milling

This paper investigates the effects of the cutting tool edge radius on the cutting forces and stability lobes in micro-milling. The investigation is conducted based on recently developed models for prediction of micro-milling cutting forces and stability lobes. The developed models consider the nonlinearities of the micro-milling process, such as nonlinear cutting forces due to cutting velocity dependencies, edge radius effect and run-out presence. A number of finite element analyses (FEA) are performed to obtain the cutting forces in orthogonal cutting which are used for determining the micro-milling cutting forces. The chip morphology obtained for different tool edge radii using FEA is presented. It is observed that at large tool edge radii the influence of the ploughing effect become more significant factor on the chip morphology. The results related to micro-milling cutting forces and stability lobes show that by enlarging the tool edge radius the micro-milling cutting forces increase while the stability limits decrease.

Model Based Planning of Complex Micro-manufacturing Strategies

In recent decades micro-manufacturing becomes increasingly important. Complex multi-material and multi-functional products are required in industries such as bio-medicine, transport, consumer electronics etc. These products, however, cannot be made by single process. Combination of various shaping and assembling processes is required. This paper, gives a systematic overview on the topic of process changing. Clear and systematic process classification system and appropriate design and modelling strategy are presented. Special emphasis is put on planning of complex manufacturing chains. This paper shall help process engineers to make their decisions easier.