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We consider a horizontally mounted two‐link manipulator of which only the first joint is actuated and the friction in the second joint is neglected. As a consequence, predefined equilibrium points are difficult to reach and point‐to‐point control is a challenging task. Starting from a partially feedback linearized model, a transformation to Byrnes‐Isidori normal form is presented. Based on this decomposition,...
The eigenfrequencies of a mechanical system depend on several parameters such as mass‐, damping‐, stiffness‐distribution and boundary conditions. Variation of these parameters results in variation of the Frequency Response Function (FRF). An eigenfrequency can be tracked by resonant excitation with a Phase‐Locked Loop (PLL) in order to monitor a certain parameter. As an example, a cantilever beam...
One major problem when discretizing boundary integral equations are the spatial singularities of the appearing integral kernels. For some classical problems, e.g. elastodynamics, this problem has been solved through partial integration yielding at most weakly singular integrals. The aim is to adopt this procedure to the modelling of porous media with boundary elements. This idea is justified by the...
Nowadays fluid structure interaction methods gain more and more importance. For room acoustical problems the coupling to realistic boundary conditions, absorbers and reflectors, is still a remaining challenge in the optimization process for the frequency response of the acoustic volume. The following work will present a coupling method based on the Component Mode Synthesis and Hamilton's Principle...
Based on the theory of mixtures, a dynamic three phase model for partially saturated poroelasticity is established. This model is applied to a one‐dimensional unsaturated poroelastic column and an analytical solution in the Laplace domain is deduced. By using the Convolution Quadrature Method, the solution in the time domain is obtained. Using some widely distributed porous materials as rock, soil...
This work deals with the analytical and numerical simulation of the loads on cylindrical offshore structures due to breaking waves. We investigate breaking waves impact on a cylindrical structure on the surface of the water by using a multiphase flow model of immiscible fluids based on the Volume of Fluid (VOF) method. Different numerical schemes are applied to identify the sharp interface between...
The piston rod of a reciprocating compressor is sealed with elastic cylindrical sealing elements. Across the sealings the pressure drops from the operating pressure to the ambient pressure. The lubrication gap between the elastic sealing and reciprocating piston rod is studied with the aim to find conditions of a leakage free sealing. The flow in the lubrication gap and the elastic deformation of...
In this paper the characteristics of subsystems obtained by the approximate and exact method were compared, because purpose is to answer to the question if the method can be used to nominate the characteristics of mechatronic systems. In this paper frequency‐modal analysis have been presented for the mechanical system, that means flexibly vibrating free beam. The model of the beam was presented...
We present an efficient model for the simulation of phase‐transformations in polycrystalline materials. As a basis, we use a thermodynamically consistent, one‐dimensional phase‐transformation model, which is embedded into a micro‐sphere formulation in order to be able to simulate three‐dimensional boundary value problems. The underlying evolution equations are solved efficiently using a newly developed...
Fibre or textile reinforcement is commonly used in order to enhance the directional mechanical and thermal properties of rubbery polymers. For the quantitative analysis and design of fibre reinforced elastomeric materials, precise description of the composite behaviour plays a crucial role. To this end, a coupled thermomechanical formulation at finite strains is presented. The anisotropic thermal...
Bekanntlich verwendet man in der Materialwissenschaft „Prinzipe“, um die mögliche Form von Materialgleichungen einzuschränken. Insbesondere sind hier das Entropieprinzip (etwa in der Version der Thermodynamik irreversibler Prozesse (TIP) nach [1], der Clausius‐Duhem Formalismus nach [2] oder die Methode der Lagrange‐Multiplikatoren [3]) zu nennen. Darüber hinaus existieren Extremalprinzipe, also „Derivate“...
A common treatment in manufacturing web‐like thin materials like paper is to manipulate it between two cylinders under rolling contact. A roll press is sensitive to vibration, which is unwanted, because it marks the web by regular stripes. A piezoelectric actuator is an excellent device for vibration control applications because of its large force generation, very short response time and easy controllability...
Increasing transport capacity leads to new vehicle designs and increasing axle loads. Still it has to be better understood until which extend especially heavy vehicles cause corrugation of roads. Therefore, basic investigations concerning vehicle‐road interaction are helpful to augment the understanding of the basic mechanisms. Firstly, in order to investigate the oscillatory behavior of a vehicle...
Koiter's postbuckling analysis and the consistently linearized eigenvalue problem are used in sensitivity analysis of the postbuckling behavior of elastic structures. A classification of structures can be made on basis of the eigenvector of the eigenvalue problem. This classification distinguishes between structures with different quality of conversion from imperfections sensitivity into imperfection...
A conserved phase‐field model is proposed to investigate the effect of interfacial energy on the morphological evolution of the pyrolytic carbon deposit in chemical vapor deposition. The equilibrium geometry of carbon deposit islands is analytically predicted, of which the contact angle was controlled through the boundary conditions of the phase‐field parameter at the substrate surface according to...
In this work, a short overview is given, how data resulting from Electron Backscatter Diffraction (EBSD) measurements can be used to obtain a discrete version of the Orientation Distribution Function (ODF). Discrete ODFs are necessary, e.g. for micromechanically based simulations of metal forming operations based on the finite element method. To use EBSD data for simulations several processing steps...
Hydrodynamic bearings are used in many technical systems, e.g., in combustion engines, in gear boxes or in rotor systems. To model such bearings, different methods are available. Often, reduced bearing models are applied which can be incorporated into the multibody systems by analytical formulas or pre‐computed look‐up tables [1]. Such approaches are very time‐efficient but suffer from limited physical...
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