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München, Germany

Dhondt G.,MTU Aerospace Engines GmbH
International Journal of Fatigue | Year: 2014

Cracks in real applications frequently exhibit mixed-mode characteristics. At MTU a software tool CRACKTRACER3D was developed to predict mixed-mode cyclic crack propagation in a fully automatic way. It consists of a preprocessor, inserting the actual crack into a finite element input deck for the uncracked structure, a call to the free software finite element program CalculiX and a postprocessor evaluating the stress intensity factors and calculating the new crack front. This loop is repeated until some predefined criterion has been reached. In order to verify the code, mixed-mode fracture in several specimens has been simulated and compared with the experimental results. This includes the propagation of a slanted crack in a 4-point bending specimen, a Compact Tension Shear Rotation Specimen under nominal Mode-III loading and a biaxial test of a square specimen with holes. Qualitatively the crack shapes are well predicted, quantitatively the numerical results are frequently on the conservative side due to the neglect of friction and interlocking in between the crack faces. © 2013 Elsevier Ltd. All rights reserved. Source

A method for machining a workpiece. An electrode is moved linearly in the direction of the workpiece to cause material to be removed from the workpiece, at least one end of a surface of the workpiece running obliquely to a guide edge of the electrode machining this surface. The electrode is moved at least partially with the electrode surface parallel to the surface, so that during the approach to the workpiece, areas of the workpiece having an irregular edge machined at a different intensity are formed, the difference in intensity of machining on the edge of the surface to be machined being compensated in that the surface to be machined is provided with a height profile adapted to the shape of the end of the surface to be machined. A blade ring segment and blade ring is also disclosed.

MTU Aerospace ENGINES GMBH | Date: 2015-02-26

A method of producing holes in a component, in particular of turbomachines, wherein each hole extends from a first, outer surface to a second, inner surface of the component and wherein the method has, for example, the following steps: (i) producing a 3D model of the actual geometry of the component, at least for the region of the holes; (ii) adapting each hole on the basis of the actual geometry of the component; and (iii) generating a production program for each individual hole. In this way, the process quality and with it the quality of the holes increases, because the offset of holes caused by component tolerances is avoided and the drilling funnels are formed according to specification. Furthermore, drilling defects on account of the offset of holes and/or cores can be avoided. Overlapping holes caused by component tolerances are likewise avoided.

A gas turbine jet engine having a main flow channel (

MTU Aerospace ENGINES GMBH | Date: 2013-03-11

A gas turbine, in particular an aircraft engine, having a housing in which at least one guide blade (

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