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Preprint
Numerical crack path prediction under mixed-mode loading in 1D quasicrystals
(2017-03)
Quasicrystals are being implemented in industry since this new class of materials appears to have some peculiar properties. However, the fracture behavior of quasicrystals is not yet clear, which could be a hindrance to its wide usage. This work adopts the generalized linear elastic framework of fracture theory in quasicrystals and develops numerical tools in a finite element environment to compute the fracture quantities. Crack growth is simulated in diverse specimens undergoing an intrinsic mixed-mode loading and ...
Aufsatz
On the track of human errors - Procedure and results of an innovative assembly planning method
(2018-03-07)
Manual assembly operations are the endmost place of the production process and with it represent a melting pot for organizational, time-related and qualitative errors of manufacturing. Because competitive advantages are increasingly determined in the manual assembly, the creation of economical and reliable work steps is of fundamental importance for future business success. For that reason, at the institute of the authors, a procedure has been developed to use the knowledge of the Expert System for Task Taxonomy that ...
Aufsatz
Microscale-Motivated Continuum Damage Simulations of Brittle Ceramics under Thermomechanical Loading
(2016-05-02)
Two approaches towards modeling damage in a brittle material caused by thermomechanical loading are presented.
Bothrelyonmicrocrack growth, in the first case in ahomogeneousmatrix, in the second one at grain boundaries.Two-scale simulations e.g. of thermal shocks applied to single-phase or layered structures are performed in connection with the finite element method. Damage and crack patterns are predicted just as quantities like residual strength or critical temperature jumps.
Teil eines Buches
Anforderungsklassifizierung in der Fahrdynamik und Fahrerassistenz als Grundlage einer kundenorientierten Produktqualität und Kundenzufriedenheit
(kassel university press, 2016)
Die BMW Group zählt zu den weltweit führenden Herstellern von Premiumprodukten und Anbietern von Mobilitätsdienstleistungen in der Automobilindustrie. Durch zunehmende Qualitätsansprüche der Kunden gewinnt auch die Anforderungsklassifizierung an Bedeutung. Gerade in Zeiten steigenden Wettbewerbsdrucks und kürzeren Innovationszyklen ist eine genaue Kenntnis der kundenseitigen Anforderungsmerkmale und deren Auswirkungen auf die produktbezogene Qualitätswahrnehmung und Kundenzufriedenheit von großer Bedeutung. Die ...
Aufsatz
Adapting Kano's Theory for weighting and implementing customers requirements on a software tool for assessing human reliability in manual assembly
(2018)
The following paper illustrates the conception of an Excel-based software tool developed to predict human error probabilities in manual assembly lines. In this regard, the paper clearifies how reliable risk analyses of manual work tasks can be carried out with the help of a software tool. Furthermore, to initiate a high user-friendliness, a high acceptance and a high level of dissemination, this paper deals with a Kano survey concerning customer requirements on the developed software tool. As a result, it will be ...
Aufsatz
Sensor Concept Based on Piezoelectric PVDF Films for the Structural Health Monitoring of Fatigue Crack Growth
(2011)
A new sensor concept for monitoring fatigue crack growth in technical structures is presented. It allows the in-situ determination of the position of the crack tip as well as the fracture mechanical quantities. The required data are obtained from a piezoelectric polymer film, which is attached to the surface of the monitored structure. The stress intensity factors and the crack tip position are calculated from electrical potentials obtained from a sensor array by solving the non-linear inverse problem.
Aufsatz
Crack path predictions and experiments in plane structures considering anisotropic properties and material interfaces
(2015-09-28)
In many engineering applications special requirements are directed to a material's fracture behavior and the prediction of crack paths. Especially if the material exhibits anisotropic elastic properties or fracture toughnesses, e.g. in textured or composite materials, the simulation of crack paths is challenging. Here, the
application of path independent interaction integrals (I-integrals), J-, L- and M-integrals is beneficial for an accurate crack tip loading analysis.
Numerical tools for the calculation of loading ...
Aufsatz
Increasing energy efficiency of milk product batch sterilisation
(2018-09-07)
The food industry is a large energy consumer and most heat demands in food processing are low-temperature. The aim of this study is to develop and simulate innovative retrofits or redesigns that unlock the heat recovery potential of industrial batch sterilisation processes. The case study focuses on the whey cream process, although the method and results apply to similar batch sterilisation processes. The initial situation is compared to energy efficient designs based on “Energy Storage” and “Rescheduling”. Using a ...
Aufsatz
Weak and strong bi-material interfaces and their influence on propagating cracks in plane elastic structures
(2017-09-06)
The developing crack paths in heterogeneous structures are the result of the inhomogeneous state of stress. The latter stems from e.g. voids or inclusions in an elastic matrix, which are bonded either by strong or weak interfaces. Besides the stiffness of an inclusion, the kind of interface has a decisive influence on the state of stress and therefore on propagating cracks. It is experimentally proven that cracks tend to grow towards regions with lower stiffness (Tilbrook et al., 2006; Judt et al., 2015), therefore ...