Author
Junhong Park
Other affiliations: Purdue University, University College of Engineering
Bio: Junhong Park is an academic researcher from Hanyang University. The author has contributed to research in topics: Vibration & Noise. The author has an hindex of 18, co-authored 125 publications receiving 960 citations. Previous affiliations of Junhong Park include Purdue University & University College of Engineering.
Topics: Vibration, Noise, Beam (structure), Bending stiffness, Flexural strength
Papers published on a yearly basis
Papers
More filters
TL;DR: The facile fabrication of a Stretchable Acoustic Device (SAD) using Galinstan voice coil where the SAD is operated by the electromagnetic interaction between the liquid metal coil and a Neodymium (Nd) magnet is demonstrated.
Abstract: Considering the various applications of wearable and bio-implantable devices, it is desirable to realize stretchable acoustic devices for body-attached applications such as sensing biological signals, hearing aids, and notification of information via sound. In this study, we demonstrate the facile fabrication of a Stretchable Acoustic Device (SAD) using liquid metal coil of Galinstan where the SAD is operated by the electromagnetic interaction between the liquid metal coil and a Neodymium (Nd) magnet. To fabricate a liquid metal coil, Galinstan was injected into a micro-patterned elastomer channel. This fabricated SAD was operated simultaneously as a loudspeaker and a microphone. Measurements of the frequency response confirmed that the SAD was mechanically stable under both 50% uniaxial and 30% biaxial strains. Furthermore, 2000 repetitive applications of a 50% uniaxial strain did not induce any noticeable degradation of the sound pressure. Both voice and the beeping sound of an alarm clock were successfully recorded and played back through our SAD while it was attached to the wrist under repeated deformation. These results demonstrate the high potential of the fabricated SAD using Galinstan voice coil in various research fields including stretchable, wearable, and bio-implantable acoustic devices.
83 citations
TL;DR: This review provides a summary of studies applying machine learning algorithms for fault monitoring and a brief interpretation of deep neural networks is provided to guide further applications in the structural vibration analysis.
Abstract: With the rapid progress in the deep learning technology, it is being used for vibration-based structural health monitoring. When the vibration is used for extracting features for system diagnosis, it is important to correlate the measured signal to the current status of the structure. The measured vibration responses show large deviation in spectral and transient characteristics for systems to be monitored. Consequently, the diagnosis using vibration requires complete understanding of the extracted features to discard the influence of surrounding environments or unnecessary variations. The deep-learning-based algorithms are expected to find increasing application in these complex problems due to their flexibility and robustness. This review provides a summary of studies applying machine learning algorithms for fault monitoring. The vibration factors were used to categorize the studies. A brief interpretation of deep neural networks is provided to guide further applications in the structural vibration analysis.
78 citations
TL;DR: In this paper, a transfer function method was used to measure the bending and shear stiffness of complex structures and the damping of structural vibration using porous and granular materials, and a proper equation of motion for the structural vibration should be used to obtain reliable data.
68 citations
TL;DR: In this paper, two different models were developed to calculate the optimal support stiffness that minimizes the velocity response of homogeneous plates, based on the wave propagation at the edge and the Rayleigh-Ritz method.
51 citations
TL;DR: In this article, the authors investigated the mechanical and dynamic properties of the carbon fiber reinforced polymer concrete (CFRPC) to reduce the vibration/noise problems on rail slab and found that the CFRPC sleeper was decreased by 4dB compared to that using the polymer concrete sleeper, from the impact test of the scaled model of the railway structure.
46 citations
Cited by
More filters
01 Jan 1998
TL;DR: In this paper, the authors explore questions of existence and uniqueness for solutions to stochastic differential equations and offer a study of their properties, using diffusion processes as a model of a Markov process with continuous sample paths.
Abstract: We explore in this chapter questions of existence and uniqueness for solutions to stochastic differential equations and offer a study of their properties. This endeavor is really a study of diffusion processes. Loosely speaking, the term diffusion is attributed to a Markov process which has continuous sample paths and can be characterized in terms of its infinitesimal generator.
2,446 citations
1,604 citations
TL;DR: A stretchable polyaniline nanofiber temperature sensor array with an active matrix consisting of single-walled carbon nanotube thin-film transistors is demonstrated and gives mechanical stability under biaxial stretching, and the resultant spatial temperature mapping does not show any mechanical or electrical degradation.
Abstract: A stretchable polyaniline nanofiber temperature sensor array with an active matrix consisting of single-walled carbon nanotube thin-film transistors is demonstrated. The integrated temperature sensor array gives mechanical stability under biaxial stretching of 30%, and the resultant spatial temperature mapping does not show any mechanical or electrical degradation.
335 citations
TL;DR: Material innovation and structural design for the preparation of flexible hybrid electronics are reviewed, a brief chronology of these advances is given, and biomedical applications in bioelectrical monitoring and stimulation, optical monitoring and treatment, acoustic imitation and monitoring, bionic touch and body-fluid testing are described.
Abstract: Recent advances in material innovation and structural design provide routes to flexible hybrid electronics that can combine the high-performance electrical properties of conventional wafer-based electronics with the ability to be stretched, bent, and twisted to arbitrary shapes, revolutionizing the transformation of traditional healthcare to digital healthcare. Here, material innovation and structural design for the preparation of flexible hybrid electronics are reviewed, a brief chronology of these advances is given, and biomedical applications in bioelectrical monitoring and stimulation, optical monitoring and treatment, acoustic imitation and monitoring, bionic touch, and body-fluid testing are described. In conclusion, some remarks on the challenges for future research of flexible hybrid electronics are presented.
325 citations
TL;DR: In this article, structural vibrations caused by a flowing fluid were investigated and it was shown that whenever a structure is exposed to a flowing liquid, it will vibrate and vibrate strongly.
Abstract: Structural vibrations caused by a flowing fluid. Whenever a structure is exposed to a flowing fluid,…
279 citations