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Finite Element Modelling of Wheel and Rail in Rolling Contact

100%

Damme S. , Zastrau B. W.

Machine Dynamics Problems

2004

tom Vol. 28, No. 1

57-65

The evaluation of the contact patch as well as the distribution of stress and strain in rolling contact requires a geometrically and materially nonlinear approach. The paper gives an overview over the theoretical background of the arbitrary Lagrangian-Eulerian formulation of the dynamics of rolling bodies. Contact formulations for dynamic contact conditions are developed using a velocity oriented approach. The transcription into the Finite Element Method, temporarily limited to an elastic material law, is given. Numerical examples for three dimensional simulations demonstrate the applicability of the developed program package.

Model order reduction of Mikota’s vibration chain including damping effects by means of proper orthogonal decomposition

100%

Weber W. E. , Zastrau B. W.

tom Vol. 56 nr 2

511--521

In engineering disciplines, both in scientific and practical applications, systems with a tremendous number of degrees of freedom occur. Hence, there is a need for reducing the computational effort in investigating these systems. If the system behaviour has to be calculated for many time instances and/or load scenarios, the need for efficient calculations further increases. Model order reduction is a common procedure in order to cope with such large systems. The aim of model order reduction is to reduce the (computational) effort in solving the given task while still keeping main features of the respective system. One approach of model order reduction uses the proper orthogonal decomposition. This approach is applied to Mikota’s vibration chain, a linear vibration chain with remarkable properties, where two cases of an undamped and a damped structure are investigated.

On the Avoidance of POISSON Thickness Locking in Surface-Related Shell Theories by an Extension of the EAS Method

80%

Schlebusch R. , Matheas J. , Zastrau B. W.

Machine Dynamics Problems

2002

tom Vol. 26, No. 4

101-114

The enhanced assumed strain (EAS) method as introduced by Simo and Rifai (1990), Buchter and Ramm (1992), Buchter et al. (1994) represents a very efficient concept for the prevention and reduction of locking phenomena. The utilization of the EAS method to prevent POISSON thickness locking in the context of a 6-parameter shell formulation without rotational degrees of freedom and the middle surface as reference surface is a well known procedure in literature, Bischoff (1999), Klinkel (2000). In this contribution the EAS method is applied in a shell theory that uses an outer surface as the reference surface and is therefore called a surface-related shell theory. In contrast to the middle surface shell theory the EAS concept to prevent POISSON thickness locking in connection with surface-related formulations evokes a coupling of the membrane force and moment tensor, if the orthogonality condition is evaluated. Two additional concepts against locking phenomena are introduced: the assumed natural strain (ANS) concept, cp. Simo and Hughes (1986), and the discrete shear gap (DSG) concept, cp Bletzinger et al. (1998). The combination of the aforementioned concepts leads to an efficient finite volume shell element that is demonstrated in numerical examples.