October 2013

EFFECT OF HEAT LOAD TO THE FORMING MACHINES

MM (Modern Machinery) Science Journal, October 2013
 
Zdenek Chval
University of West Bohemia, Faculty of Mechanical Engineering, Department of Machine Design,
Univerzitni 8, 306 14 Pilsen, Czech Republic
e-mail: zdchval@kks.zcu.cz
Abstract
When designing a forming machine for hot forming, it is necessary to take into account the effects of heat on the construction. Therefore, it is important to perform an in-depth analysis of the possible influences of temperature on individual parts of the machine and subsequent effects on durability of the construction and machine accuracy. The article deals with the thermal analysis of a crank forging press.
Keywords: forming machines, hydraulic forging press, mechanical crank forging press, heat load, FEM simulation
 
 
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DEVELOPMENT OF A CUTTING TOOL FOR COMPOSITES WITH THERMOPLASTIC MATRIX

MM (Modern Machinery) Science Journal, October 2013

Petr Masek, Pavel Zeman, Petr Kolar
Czech Technical University in Prague, Research Center of Manufacturing Technology, Prague, Czech Republic
e-mail: p.masek@rcmt.cvut.cz

Abstract
Fibre reinforced thermoplastic composites (FRTC) are becoming an increasingly important material for a wide range of applications. Thus, the demand for high performance tools for machining of this material is increasing. The main goal of the presented research results is to decrease cutting costs during trimming operations of thin plates and to increase the quality of machined composite materials by suitable shape, geometry and material of the cutting tool and by suitable cutting conditions. Statistical methods were used in order to obtain the control factors (cutting conditions) which are the most important for machining FRTC. Subsequently, an optimal adjustment of cutting conditions was identified. The paper is a brief summary of the cutting tool development. It includes important parts of tests and their results as well as some interesting findings implicit in experiments and measuring.

Keywords: thermoplastic composite, cutting tool, cutting conditions, development, milling
 

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KRYLOV SUBSPACE MODEL ORDER REDUCTION OF LARGE SCALE FINITE ELEMENT DYNAMICAL SYSTEMS

MM (Modern Machinery) Science Journal, October 2013
Jaroslav Sindler, Matej Sulitka
Czech Technical University in Prague, Faculty of Mechanical Engineering, Department of Production Machines and Equipment,
Prague, Czech Republic
e-mail: m.sulitka@rcmt.cvut.cz

Abstract
The purpose of model order reduction (MOR) techniques is to provide a fast response approximate solution of a given system. Naturally the error induced due the approximation should be as low as possible. The paper presents the benefits of using a Krylov subspace based MOR for solution of large scale finite element (FE) dynamical systems. The main advantage of using a Krylov MOR is significantly shortening of the computational time while an induced error is almost negligible or very low. The process will be presented on structural harmonic analysis oflarge machine tool and a transient thermal analysis of thermal subsea equipment.
Keywords: model order reduction, Krylov subspace, large FEA, machine tool, subsea equipment, system dynamics, transient thermal analysis
 
 
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