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Michaela Kostelecká, Daniel Kytýř, Tomáš Doktor
STUDY OF DEGRADATION OF FIBRE – CEMENT PLATES WITH DIFFERENT TYPES OF NON – METALIC FIBRES

Results from series of tests carried out on nine mixture formulas are the main data set. Asbestosfree plates bonded by hydro-silicate matrix and reinforced by organic fibers were produced from these mixture formulas. Within the scope of this project, the following activities were carried out: finding out the dimensional and weight characteristics of the plates, bending strength under normal conditions, the influence of frost on bending strength, the influence of putting the plates into hot water on bending strength, the impermeability of plates and measurement of change of length in the direction along and across the fibers.

Rainer Klauke, Jörn Ihlemann
ANALYSIS OF TECHNICAL RUBBER MATERIALS USING SIMPLE SHEAR DEFORMATIONS WITH ROTATING AXES

In opposition to metallic materials, technical elastomers exhibit a variety of different material properties like nonlinearity or inelastic material behavior. The measurement of those properties and the determination of the material parameters connected to them often requires several different experimental setups. In the presented article the setup of an experimental rig is introduced, which allows the measurement of dynamic parameters, while at the same time the input signals preserve a quasi-static character. With the experimental rig it is possible to decouple elastic and inelastic processes within the material as well as to investigate consider new and yet highly relevant aspects for the prediction of the fatigue behavior of technical rubber parts.

Paweł Kaczyński
ESTIMATION METHOD OF SPOT CONNECTORS MECHANICAL PROPERTIES

Clinch joining technique can be successfully used in many industries for joining of thin-walled profiles. This solution brings multiple benefits to the producers. The most important are: elimination of metal surface preparation, reduction of the energy consumption and negative influence of the heat zone. Furthermore, joining process does not cause bore dust, and does not require gas shroud, generating noise at a low level of intensity.

Ines Jölly, Andreas Hausberger, István Gódor, Thomas Schwarz
DEVELOPMENT OF A TRIBOLOGICAL TESTING METHODOLOGY FOR DETERMINING FRICTION AND WEAR RELATED PROPERTIES OF TPU SEALING MATERIALS

Mechanical seal performance critically depends on the tribological performance of the sealing material. Former research work clearly indicates that the in service behaviour of TPU seals is associated with the sliding velocity (v) and the contact pressure (p), hence a compelling testing process to determine and compare the friction and wear related properties based on pvvariations is of outermost importance. This paper chronicles an implementation approach for the development of a testing methodology capable to declare the p-v-dependency on the tribological performance.

Franz Hiptmair, Zoltan Major, Vitor Barroso, Sabine Hild
EXPERIMENTAL CHARACTERIZATION OF MAGNETOELASTOMERS AND DETERMINATION OF MATERIAL MODEL PARAMETERS FOR SIMULATIONS

To assess the applicability of magnetic metallic particle filled soft polymeric materials (i.e. gels and elastomers, termed as magnetoelastomers) for practical industrial applications, comprehensive characterization of the rheological and mechanical behaviour is essential.
For this study Polydimethylsiloxane (PDMS) was selected as matrix-material. Iron particles of various shapes (aspect ratios) and surface treatments were added as fillers in various amounts. Isotropic specimens were prepared and subjected to rheological and dynamic mechanical measurements in presence or absence of homogeneous magnetic fields. In order to achieve the necessary field homogenity in the region of the test specimen, novel set-ups were developed using magnetostatic simulation software and rapid prototyping tools.

Désirée Gröber, Erhard Leidich, Bohumil Brůžek
COMPARATIVE INVESTIGATION OF STATIC FRICTION COEFFICIENT OF 6082 ALUMINIUM ALLOY WITH THE MATERIAL CONDITIONS T651 AND EQUAL-CHANNEL ANGULAR PRESSING (ECAP)

Knowledge of occurring friction is very important in mechanical engineering – both in order to ensure reliable friction-locked joints and to reduce energy loss. Friction coefficients are influenced by many factors, like hardness, material strength and structural conditions. These materials properties can be improved through ultrafine graining of aluminium alloys by equalchannel angular pressing (ECAP) with subsequent aging treatment. Therefore the influence of ECAP material conditions on the frictional behaviour of 6082 aluminium alloy is investigated in this paper.

Joanna Furgała, Stanisława Szarska, Jerzy Detyna
THE INFLUENCE OF ADHESION ON THE STATE OF THE SURFACE LAYER OF CONTACT LENSES

Several research focuses on assessing the properties of contact lenses, due to the increasing number of users, whose needs grow because of the conditions in which they work (work at the computer room air-conditioned). The main aspect of providing comfortable wearing contact lenses is their good wettability. Studies on wettability are evolving all the time because of the difficulties to be faced, e.g. incomplete blinking. Hence the search for closest to the natural conditions of the test method,which reflects the reaction of the cornea-contact lens-tear film.
In order to understand the mechanism of interaction between different elements of the system discussed, there need to refer to the fundamental rights of the interactions at the interface between different phases.
Adhesion of a liquid to a solid phase is a physicochemical process, which involves tying up each of these two phases as a result of intermolecular interactions. Wettability of the test body depends on the surface tension of the liquid present in the system, and the hydrophilicity of the surface. However, mostly used to determine the wettability, is contact angle measurement.
The main purpose of this study was to investigate various soft contact lens care solution adhesion to the surface of different types of contact lenses. In addition to standard contact angle measurements using goniometer,a modified method for hydrophilicity measurement of contact lenses, was applied.

Tomáš Doktor, Daniel Kytýř, Jaroslav Valach , Ondřej Jiroušek , Michaela Kostelecká
IMPROVEMENTS OF AN ANALYSIS TOOL FOR THE PORE SIZE DISTRIBUTION ASSESSMENT

Knowledge of the inner structure is an important prerequisite for estimation of the mechanical properties of heterogeneous materials. This article is focused on the assessment of pore size distribution of a porous material.

Adam Czech, Sascha Müller, Lothar Kroll
COMPUTER TOMOGRAPHY AND IMAGE PROCESSING FOR ANISOTROPIC DAMAGE DETECTION ON FIBRE REINFORCED PLASTICS

Volume computer tomography (VCT) is an established non destructive testing method, which offers the possibility to capture internal structural damage three-dimensionally. Thus, the complex failure mechanism of endless fibre reinforced plastics can be visualized and classified into the basis failure modes: fibre failure (FF) and inter fibre failure (IFF) taking different loading types into account: tension, compression and shear. A new approach analyzes these VCT data in combination with image processing algorithms to identify the anisotropic damage parameters of pre-damaged CFRP tubes in dependence of the real arising failure modes. Thereby the kind, size and orientation of the detected failure will be estimated automatically. The software was developed on basis of the MATLAB environment and provides input data for a subsequently finite element analysis in ANSYS.

Barthel Brylka, Felix Fritzen, Thomas Böhlke, Kay André Weidenmann
INFLUENCE OF MICRO-STRUCTURE ON FIBRE PUSH-OUT TESTS

The investigations presented in this paper focus on the simulation of push-out tests on a long fibre reinforced thermoplastic (LFT) manufactured in a compression moulding process. The microstructure of LFT is strongly influenced by the manufacturing process and shows inhomogeneous distribution and orientation of the glass fibres. Figure 1 shows the surface of a polished specimen, which has been cut normal to the melt flow direction.
The influence of geometrical parameters like, e.g., fibre arrangements and fibre misalignment is still not fully understood. For the interpretation of experimental data the afore-mentioned parameters must be taken into account. Therefore, a numerical study is performed to determine these influences on the mechanical behaviour in push-out experiments.

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