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49 results on '"Kollosche, Matthias"'

1. Soft Capacitors for Wave Energy Harvesting

Author

Ahnert, Karsten, Abel, Markus, Kollosche, Matthias, Jørgensen, Per Jørgen, and Kofod, Guggi

Subjects
Condensed Matter - Soft Condensed Matter
Abstract

Wave energy harvesting could be a substantial renewable energy source without impact on the global climate and ecology, yet practical attempts have struggle d with problems of wear and catastrophic failure. An innovative technology for ocean wave energy harvesting was recently proposed, based on the use of soft capacitors. This study presents a realistic theoretical and numerical model for the quantitative characterization of this harvesting method. Parameter regio ns with optimal behavior are found, and novel material descriptors are determined which simplify analysis dramatically. The characteristics of currently ava ilable material are evaluated, and found to merit a very conservative estimate of 10 years for raw material cost recovery., Comment: 16 pages, 7 figures

Published
2011
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8. A Wearable Textile-Embedded Dielectric Elastomer Actuator Haptic Display

Author

Lee, Dae-Young, Jeong, Seung Hee, Cohen, Andy J., Vogt, Daniel M., Kollosche, Matthias, Lansberry, Geoffrey, Menguc, Yigit, Israr, Ali, Clarke, David R., Wood, Robert J., Lee, Dae-Young, Jeong, Seung Hee, Cohen, Andy J., Vogt, Daniel M., Kollosche, Matthias, Lansberry, Geoffrey, Menguc, Yigit, Israr, Ali, Clarke, David R., and Wood, Robert J.

Abstract

With advances in mobile computing and virtual/augmented reality technologies, communicating through touch using wearable haptic devices is poised to enrich and augment current information delivery channels that typically rely on sight and hearing. To realize a wearable haptic device capable of effective data communication, both ergonomics and haptic performance (i.e., array size, bandwidth, and perception accuracy) are essential considerations. However, these goals often involve challenging and conflicting requirements. We present an integrated approach to address these conflicts, which includes incorporating multilayered dielectric elastomer actuators, a lumped-parameter model of the skin, and a wearable frame in the design loop. An antagonistic arrangement-consisting of an actuator deforming the skin-was used to achieve effective force transmission while maintaining a low profile, and the effect of the wearable frame and structure was investigated through lumped-model analysis and human perception studies.

Published
2022
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15. Ionogels based on poly(methyl methacrylate) and metal-containing ionic liquids

Author

Zehbe, Kerstin, Kollosche, Matthias, Lardong, Sebastian, Kelling, Alexandra, Schilde, Uwe, and Taubert, Andreas (Prof. Dr.)

Subjects
ddc:570, ddc:540, Institut für Chemie
Abstract

Ionogels (IGs) based on poly(methyl methacrylate) (PMMA) and the metal-containing ionic liquids (ILs) bis-1-butyl-3-methlimidazolium tetrachloridocuprate(II), tetrachloride cobaltate(II), and tetrachlorido manganate(II) have been synthesized and their mechanical and electrical properties have been correlated with their microstructure. Unlike many previous examples, the current IGs show a decreasing stability in stress-strain experiments on increasing IL fractions. The conductivities of the current IGs are lower than those observed in similar examples in the literature. Both effects are caused by a two-phase structure with micrometer-sized IL-rich domains homogeneously dispersed an IL-deficient continuous PMMA phase. This study demonstrates that the IL-polymer miscibility and the morphology of the IGs are key parameters to control the (macroscopic) properties of IGs.

Published
2017

17. Standards for dielectric elastomer transducers

Author

Carpi, Federico, Anderson, Iain, Bauer, Siegfried, Frediani, Gabriele, Gallone, Giuseppe, Gei, Massimiliano, Graaf, Christian, Jean-Mistral, Claire, Kaal, William, Kofod, Guggi, Kollosche, Matthias, Kornbluh, Roy, Lassen, Benny, Matysek, Marc, Michel, Silvain, Nowak, Stephan, Pei, Qibing, Pelrine, Ron, Rechenbach, Bjorn, Rosset, Samuel, and Shea, Herbert

Subjects
Institut für Physik und Astronomie
Abstract

Dielectric elastomer transducers consist of thin electrically insulating elastomeric membranes coated on both sides with compliant electrodes. They are a promising electromechanically active polymer technology that may be used for actuators, strain sensors, and electrical generators that harvest mechanical energy. The rapid development of this field calls for the first standards, collecting guidelines on how to assess and compare the performance of materials and devices. This paper addresses this need, presenting standardized methods for material characterisation, device testing and performance measurement. These proposed standards are intended to have a general scope and a broad applicability to different material types and device configurations. Nevertheless, they also intentionally exclude some aspects where knowledge and/or consensus in the literature were deemed to be insufficient. This is a sign of a young and vital field, whose research development is expected to benefit from this effort towards standardisation.

Published
2015

18. Elastic FRET sensors for contactless pressure measurement

Author

Morgner, Frank, primary, Bennemann, Mark, additional, Cywiński, Piotr J., additional, Kollosche, Matthias, additional, Górski, Krzysztof, additional, Pietraszkiewicz, Marek, additional, Geßner, André, additional, and Löhmannsröben, Hans-Gerd, additional

Published
2017
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23. Two types of transitions to wrinkles in dielectric elastomers

Author

Zhu, Jian, Kollosche, Matthias, Lu, Tongqing, Kofod, Guggi, and Suo, Zhigang

Subjects
Institut für Physik und Astronomie
Abstract

A membrane of a dielectric elastomer coated with compliant electrodes may form wrinkles as the applied voltage is ramped up. We present a combination of experiment and theory to investigate the transition to wrinkles using a clamped membrane subject to a constant force and a voltage ramp. Two types of transitions are identified. In type-I transition, the voltage-stretch curve is N-shaped, and flat and wrinkled regions coexist in separate areas of the membrane. The type-I transition progresses by nucleation of small wrinkled regions, followed by the growth of the wrinkled regions at the expense of the flat regions, until the entire membrane is wrinkled. By contrast, in type-II transition, the voltage-stretch curve is monotonic, and the entire flat membrane becomes wrinkled with no nucleation barrier. The two types of transitions are analogous to the first and the second order phase transitions. While the type-I transition is accompanied by a jump in the vertical displacement, type-II transition is accompanied by a continuous change in the vertical displacement. Such transitions may enable applications in muscle-like actuation and energy harvesting, where large deformation and large energy of conversion are desired.

Published
2012

25. Standards for dielectric elastomer transducers

Author

Carpi, Federico, primary, Anderson, Iain, additional, Bauer, Siegfried, additional, Frediani, Gabriele, additional, Gallone, Giuseppe, additional, Gei, Massimiliano, additional, Graaf, Christian, additional, Jean-Mistral, Claire, additional, Kaal, William, additional, Kofod, Guggi, additional, Kollosche, Matthias, additional, Kornbluh, Roy, additional, Lassen, Benny, additional, Matysek, Marc, additional, Michel, Silvain, additional, Nowak, Stephan, additional, O’Brien, Benjamin, additional, Pei, Qibing, additional, Pelrine, Ron, additional, Rechenbach, Björn, additional, Rosset, Samuel, additional, and Shea, Herbert, additional

Published
2015
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26. Strongly enhanced sensitivity in elastic capacitive strain sensors

Author

Massachusetts Institute of Technology. Department of Civil and Environmental Engineering, Laflamme, Simon, Kollosche, Matthias, Stoyanov, Hristiyan, Kofod, Guggi, Massachusetts Institute of Technology. Department of Civil and Environmental Engineering, Laflamme, Simon, Kollosche, Matthias, Stoyanov, Hristiyan, and Kofod, Guggi

Abstract

Strain sensors based on dielectric elastomer capacitors function by the direct coupling of mechanical deformations with the capacitance. The coupling can be improved by enhancing the relative permittivity of the dielectric elastomer. Here, this is carried out through the grafting of conducting polymer (poly-aniline) to the elastomer backbone, leading to molecular composites. An enhancement in capacitance response of 46 times is observed. This could help to extend the possible range of miniaturization towards even smaller device features., Germany. Federal Ministry of Education and Research (BMBF) (project KompAkt-03X5511)

Published
2012

46. Investigation of Dynamic Properties of a Novel Capacitive-based Sensing Skin for Nondestructive Testing.

Author

Saleem, Hussam, Downey, Austin, Laflamme, Simon, Kollosche, Matthias, and Ubertini, Filippo

Subjects
NONDESTRUCTIVE testing, MAGNETIC testing, ELECTROMECHANICAL devices, POISSON'S ratio, ELECTRIC capacity
Abstract

A capacitive-based soft elastomeric strain sensor was recently developed by the authors for structural health monitoring applications. Arranged in a network configuration, the sensor becomes a sensing skin, where local deformations can be monitored over a global area. The sensor transduces a change in geometry into a measurable change in capacitance, which can be converted into strain using a previously developed electromechanical model. Prior studies have demonstrated limitations of this electromechanical model for dynamic excitations beyond 15 Hz, because of a loss in linearity in the sensor's response. In this paper, the dynamic behavior beyond 15 Hz is further studied, and a new version of the electromechanical model is proposed to accommodate dynamic strain measurements up to AO Hz. This behavior is characterized by subjecting the sensor to a frequency sweep and identifying possible sources of nonlinearities beyond 15 Hz. Results show possible frequency dependence of the materials' Poisson's ratios, which are successfully modeled and integrated into the electromechanical model. This demonstrates that the proposed sensor can be used for monitoring and evaluation of structural responses up to 4 0 Hz, a range covering the vast majority of the dominating frequency responses of civil infrastructures. [ABSTRACT FROM AUTHOR]

Published
2015

48. Voltage tunable polymer laser device

Author

Döring, Sebastian, Kollosche, Matthias, Rabe, Torsten, Kofod, Guggi, and Stumpe, Joachim

Abstract

Since organic laser materials offer broad optical gain spectra they are predestined for the realization of widely tunable laser sources. Here we report on a compact organic laser device that allows for voltage controlled continuously wavelength tuning in the visible range of the spectrum by external deformation. The device consists of an elastomeric distributed feedback (DFB) laser and an electro-active elastomer actuator also known as artificial muscle. Second order DFB lasing is realized by a grating line structured elastomer substrate covered with a thin layer of dye doped polymer. To enable wavelength tuning the elastomer laser is placed at the center of the electro-active elastomer actuator. Chosen design of the actuator gives rise to homogeneous compression at this position. The voltage induced deformation of the artificial muscle is transferred to the elastomer laser and results in a decrease of grating period. This leads to an emission wavelength shift of the elastomer laser. The increase of actuation voltage to 3.25 kV decreased the emission wavelength from 604 nm to 557 nm, a change of 47 nm or 7.8%.

Published
2012
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49. Investigation of Dynamic Properties of a Novel Capacitive-based Sensing Skin for Nondestructive Testing

Author

Saleem, Hussam, Downey, Austin, Laflamme, Simon, Kollosche, Matthias, and Filippo Ubertini

Subjects
Structural health monitoring, Mechanics of Materials, Mechanical Engineering, Institut für Physik und Astronomie, Materials Science (all), Capacitive sensor, Nondestructive testing, Sensing skin, Soft elastomeric capacitor, Vibration monitoring
Abstract

A capacitive-based soft elastomeric strain sensor was recently developed by the authors for structural health monitoring applications. Arranged in a network configuration, the sensor becomes a sensing skin, where local deformations can be monitored over a global area. The sensor transduces a change in geometry into a measurable change in capacitance, which can be converted into strain using a previously developed electromechanical model. Prior studies have demonstrated limitations of this electromechanical model for dynamic excitations beyond 15 Hz, because of a loss in linearity in the sensor's response. In this paper, the dynamic behavior beyond 15 Hz is further studied, and a new version of the electromechanical model is proposed to accommodate dynamic strain measurements up to 40 Hz. This behavior is characterized by subjecting the sensor to a frequency sweep and identifying possible sources of nonlinearities beyond 15 Hz. Results show possible frequency dependence of the materials' Poisson's ratios, which are successfully modeled and integrated into the electromechanical model. This demonstrates that the proposed sensor can be used for monitoring and evaluation of structural responses up to 40 Hz, a range covering the vast majority of the dominating frequency responses of civil infrastructures.

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