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Article

Mario Rosario Chiarelli, Vincenzo Binante, Stefano Botturi, Andrea Massai, Jan Kunzmann, Angelo Colbertaldo and Diego Giuseppe Romano

The purpose of this study concerns numerical studies and experimental validation of the mechanical behavior of hybrid specimens. These kinds of composite specimens are…

Abstract

Purpose

The purpose of this study concerns numerical studies and experimental validation of the mechanical behavior of hybrid specimens. These kinds of composite specimens are made up of thin carbon and glass substrates on which some Macro Fiber Composite® (MFC) piezoelectric patches are glued. A proper design and manufacturing of the hybrid specimens as well as testing activities have been performed. The research activity has been carried out under the FutureWings project, funded by the European Commission within the 7th Framework.

Design/methodology/approach

The paper describes the basic assumptions made to define specimen geometries and to carry out experimental tests. Finite element (FE) results and experimental data (laser technique measurements) have been compared: it shows very good agreement for the displacements’ distribution along the specimens.

Findings

Within the objectives of the project, the study of passive and active deformation characteristics of the hybrid composite material has provided reference technical data and has allowed for the correct adaptation of the FE models. More in particular, using the hybrid specimens, both the bending deformations and the torsion deformations have been studied.

Practical implications

The deformation capability of the hybrid specimens will be used in the development of prototypical three-dimensional structures, that, through the electrical control of the MFC patches, will be able to change the curvature of their cross section or will be able to change the angle of torsion along their longitudinal axis.

Originality/value

The design of nonstandard specimens and the tests executed represent a novelty in the field of structures using piezoelectric actuators. The numerical and experimental data of the present research constitute a small step forward in the field of smart materials technology.

Details

Aircraft Engineering and Aerospace Technology, vol. 88 no. 5
Type: Research Article
ISSN: 1748-8842

Keywords

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Article

Walter Holweger, Marcus Wolf, Frank Walther, Werner Trojahn, Annette Mütze, Jan Kunzmann, Jürgen Schreiber, Joachim Mayer and Manuela Reichelt

The purpose of this paper is to show how controlled exposure of electromagnetic fields toward bearing steel vulnerates the microstructure. The ability of Barkhausen Noise…

Abstract

Purpose

The purpose of this paper is to show how controlled exposure of electromagnetic fields toward bearing steel vulnerates the microstructure. The ability of Barkhausen Noise signal processing is used for detecting phenomena such as dislocation and subgrain formation processes as the beginning of later failures.

Design/methodology/approach

A Barkhausen noise signal measurement equipment is used for detecting subsurface distress of 100Cr6 as a function of the applied electromagnetic and mechanical stress. Barkhausen noise signal is mathematically processed by use of fractal dimension analysis.

Findings

The paper cleary reveals significant impact of electromagnetic field in junction with mechanical loading. Electromagnetic impact depends on the magnitude of the field.

Research limitations/implications

Research limitations are given by the fact that in real field applications, e.g. wind power plants, bearings are exposed by multiple influences and the methodology is not applicable to those conditions.

Practical implications

The methodology can be applied to real field applications in condition monitoring systems. Up to now, no reasonable on‐line measurement is in use determining sub surface fatigue phenomena. The paper hence, reveals the possibility to raise condition monitoring into a new perspective.

Originality/value

The use of Barkhausen noise signal processing, as presented here, is original with respect to real field applications, such as wind power plants with a high demand in condition monitoring, especially off‐shore plants.

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Article

Tan Yigitcanlar, Antti Lönnqvist and Henna Salonius

– The paper aims to evaluate the knowledge-based urban development (KBUD) dynamics of a rapidly emerging knowledge city-region, Tampere region, Finland.

Abstract

Purpose

The paper aims to evaluate the knowledge-based urban development (KBUD) dynamics of a rapidly emerging knowledge city-region, Tampere region, Finland.

Design/methodology/approach

The paper empirically investigates Tampere region’s development achievements and progress from the knowledge perspective.

Findings

The research, through qualitative and quantitative analyses, reveals the regional development strengths, weaknesses, opportunities and threats of Tampere region.

Originality/value

The paper provides useful suggestions based on the lessons learned from the Tampere case investigation that could shed light on the KBUD journey of city-regions.

Details

VINE, vol. 44 no. 3
Type: Research Article
ISSN: 0305-5728

Keywords

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