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Hamburg, Germany

Islam M.R.,MSU CAVS | Rohbrecht J.,Simufact Engineering GMbh | Buijk A.,Simufact Americas LLC | Namazi E.,University of Winsor | And 2 more authors.
ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE) | Year: 2013

An effective and rigorous approach to determine optimum welding process parameters is implementation of advanced computer aided engineering (CAE) tool that integrates efficient optimization techniques and numerical welding simulation. In this paper, an automated computational methodology to determine optimum arc welding process control parameters is proposed. It is a coupled Genetic Algorithms (GA) and Finite Element (FE) based optimization method where GA directly utilizes output responses of FE based welding simulations for iterative optimization. Effectiveness of the method has been demonstrated by predicting optimum parameters of a lap joint specimen of two thin steel plates for minimum distortion. Three dimensional FE model has been developed to simulate the arc welding process and validated by experimental results. Subsequently, it is used by GA as the evaluation model for optimization. The optimization results show that such a CAE based method can predict optimum parameters successfully with limited effort and cost. Copyright © 2013 by ASME. Source


Terhaar J.,Saarschmiede Freiformschmiede GmbH | Blaes N.,Saarschmiede Freiformschmiede GmbH | Bokelmann D.,Saarschmiede Freiformschmiede GmbH | Schafstall H.,Simufact Engineering GMbh
Advanced Materials Research | Year: 2011

The main objective of remelting processes commonly used in the production of superalloys is to obtain a columnar dendritic solidification structure throughout the whole ingot. Besides reduced microsegregation, this cast structure features a preferred orientation, which is depending on the primary dendrites' growth direction and therefore closely related to the ingot's pool shape. As a result, non-isotropic material behaviour can be observed during initial forging operations. Since the correct prediction of material flow is a prerequisite for the further analysis of forging processes by means of numerical simulation, the solidification texture's influence on plastic flow was accounted for by the application of an anisotropic material model. The model according to Barlat was used to scale the flow stress with respect to the crystal orientations observed in the examination of vacuum arc remelted alloy 718, thereby considering the flow stress' dependency on strain, strain rate and temperature. The parameters defining the material's anisotropy could be determined by the upsetting of cylindrical specimen from a remelted ingot. © (2011) Trans Tech Publications, Switzerland. Source


Schafstall H.,Geschaftsfuhrer | Barth C.,Simufact Engineering GMbh | Jarolimeck J.,Saarschmiede Freiformschmiede GmbH
Stahl und Eisen | Year: 2012

For a number of years the German as well as the European forging industry has been facing some sustainable market trends, which have led to a paradigm shift that still lasts. The continuing shift of mass production to low cost countries and shorter product life cycles force the manufacturer to greater flexibility and efficiency in development and manufacturing. There is still a certain potential for cost savings. Utilizing these opportunities becomes especially important for very complex and energy-consuming incremental forming technologies like open die forging and ring rolling. Additional (local) property demands of the customers for their parts/components become more and more standard requirements - a change of design-oriented towards property-oriented manufacturing. In this context, the approach of an integrated simulation of entire process chains is becoming increasingly essential. Source


Schmitz G.J.,ACCESS e.V. | Engstrom A.,Thermo Calc Software | Bernhardt R.,Simufact Engineering GMbh | Prahl U.,RWTH Aachen | And 7 more authors.
JOM | Year: 2015

The Integrated Computational Materials Engineering expert group (ICMEg), a coordination activity of the European Commission, aims at developing a global and open standard for information exchange between the heterogeneous varieties of numerous simulation tools. The ICMEg consortium coordinates respective developments by a strategy of networking stakeholders in the first International Workshop on Software Solutions for ICME, compiling identified and relevant software tools into the Handbook of Software Solutions for ICME, discussing strategies for interoperability between different software tools during a second (planned) international workshop, and eventually proposing a scheme for standardized information exchange in a future book or document. The present article summarizes these respective actions to provide the ICME community with some additional insights and resources from which to help move this field forward. © 2015 The Minerals, Metals & Materials Society Source


Terhaar J.,Saarschmiede Freiformschmiede GmbH | Poppenhager J.,Saarschmiede Freiformschmiede GmbH | Bokelmann D.,Saarschmiede Freiformschmiede GmbH | Schafstall H.,Simufact Engineering GMbh | Kelkar K.,Innovative Research Inc.
7th International Symposium on Superalloy 718 and Derivatives 2010 | Year: 2010

The main objective of Vacuum Arc Remelting is to control solidification conditions in order to obtain a columnar dendritic structure throughout the whole ingot. The change in primary dendrites' growth direction, determined by the pool shape, leads to non-isotropic material properties in terms of plastic flow. As the correct prediction of flow behavior is crucial for the further analysis of forming processes (as for example in the application of damage criteria), this specific feature of remelted material has to be accounted for in the modeling of ingot breakdown. Using Barlat's formulation for the plastic flow, the structural constitution of alloy 718 VAR ingots could be linked to the alloy's plastic flow behavior by modeling the inhomogeneity of properties determined by remelting experiments and simulations. Hence, the influence of different remelting process conditions on hot workability could be examined. Compared to the commonly used von Mises approach some differences could be revealed. Source

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