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Groche P.,Institute for Production Engineering and Forming Machines | Huttel D.,Institute for Production Engineering and Forming Machines | Post P.-P.,TU Darmstadt | Schabel S.,TU Darmstadt
Production Engineering | Year: 2012

The material behavior of two different types of paperboard was characterized in tensile tests and in a new test device called paperboard bulge test. A particularly adapted hydroforming process was used to produce three-dimensional paperboard structures. Furthermore, an online measurement device to describe the mold-filling behavior is introduced. The experimental results were compared to the results obtained with an FEA investigation. The investigations showed the possibilities of the new forming process, as well as the advantages of FEA methods used to pre-define the process parameters. © 2012 German Academic Society for Production Engineering (WGP).


Muller C.,Institute for Production Engineering and Forming Machines | Groche P.,Institute for Production Engineering and Forming Machines
Tribologie und Schmierungstechnik | Year: 2014

Cold forging is a highly efficient process for the production of high quality components, even though high tribological loads may occur. Hence, complex tribological systems are essential, which have to be analyzed and refined constantly. Therefore tribometers are used. This paper introduces the necessity, the aims and the tasks of tribometers. Furthermore, certain demands, such as the representable tribological loads, the homogeneity in the contact area, the usability and the flexibility are discussed. This is necessary in order to evaluate tribometers and their applicability in cold forging. The paper at hand focuses on the examination of common tribometers used in cold forging. The topic will be completed with a survey of parameters influencing the friction coefficient, which were analyzed by the Sliding Compression Test.


Brenneis M.,Institute for Production Engineering and Forming Machines | Groche P.,Institute for Production Engineering and Forming Machines
Advanced Materials Research | Year: 2014

Smart structures consisting of a load carrying structure and smart materials with actuatory and sensory capabilities feature high potential in numerous applications. However, to master the assembly conditions of smart structures, there is a need to integrate additional design parameters such as prestress of the smart material, critical loads and electric contacting as well as insulation into the process development. This paper focusses on the design of an incremental bulk forming process to integrate piezoceramic components into an aluminum tube simultaneously to the manufacturing process. Axial forces imposed on the piezoceramic are investigated numerically and experimentally to verify the design of critical components and the process control. Within this investigation, in situ measurement of the direct piezoelectric effect provides a method to validate the numerical design with regard to failure of the piezo tube and the functional properties of the overall structure. © (2014) Trans Tech Publications, Switzerland.


Scheil J.,Physical Metallurgy PhM | Muller C.,Physical Metallurgy PhM | Steitz M.,Institute for Production Engineering and Forming Machines | Groche P.,Institute for Production Engineering and Forming Machines
Key Engineering Materials | Year: 2013

Deep Rolling and Machine Hammer Peening are mechanical surface treatments which generate hard surfaces due to cold working accompanied by the induction of compressive residual stresses. Both processes can be controlled by a variety of parameters. Up to this point, it is unclear which parameters should be used to generate hard surfaces. This paper gives a statistical approach to close this gap. Four different materials, containing 1.2379, GP4M, EN-GJL-250 and EN-JS2070, are tested using brinell hardness measurement and for each material every machining parameter is investigated. In addition an approach is given why a large ball diameter in deep rolling results in a higher hardness than a small diameter using a kinematic isotropic material FEM model of 1.2379. Copyright © 2013 Trans Tech Publications Ltd.


Groche P.,Institute for Production Engineering and Forming Machines | Vogler F.,Institute for Production Engineering and Forming Machines | Wiessner L.,Institute for Production Engineering and Forming Machines
Production Engineering | Year: 2015

Components with large cross section differences and complex geometries are not or only hardly produceable using conventional hydroforming processes at room temperature. In order to overcome this difficulty, the combination with other forming processes is promising. In the present paper a process chain consisting of rotary swaging followed by a subsequent hydroforming is examined. Local material data such as flow stress and forming limits of the preform are characterized. Kinematic hardening is found out to be the predominant material behavior. Hence, appropriate control curves for hydroforming were designed via locally assigned material data in numerical simulations. A complex geometry is thus formed with the presented process chain. It is shown that high forming ratios of preformed areas are achievable when compressive stress is superimposed by axial feeding. © 2015 German Academic Society for Production Engineering (WGP)

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