Article
Physics, Fluids & Plasmas
Jonas Helboe Joergensen, Henrik Bruus
Summary: A theoretical and numerical model is proposed in this study to investigate the thermal boundary layers and acoustic heating in microscale acoustofluidic devices. The model allows for simulation of nonlinear thermoviscous effects and three-dimensional flow using effective boundary conditions. The results demonstrate the local heating caused by friction in the boundary layers and the dominant thermoacoustic bulk streaming at high acoustic energy densities. This model is valuable for the design and fabrication of high-throughput acoustofluidic devices.
Article
Physics, Fluids & Plasmas
Bjorn G. Winckelmann, Henrik Bruus
Summary: General analytical expressions for the time-averaged acoustic radiation force on a small spherical particle suspended in a fluid and located in an axisymmetric incident acoustic wave are derived in this study. The cases of elastic solid and fluid particles are considered, and the effects of particle vibrations, acoustic scattering, acoustic microstreaming, heat conduction, and temperature-dependent fluid viscosity are all taken into account. Acoustic streaming inside the particle is also considered for the case of a fluid particle. No restrictions are placed on the widths of the viscous and thermal boundary layers relative to the particle radius. The resulting acoustic radiation force is compared with previous theories in the literature, and limits of agreement as well as deviations in specific cases of particle and fluid materials are identified.
Article
Physics, Multidisciplinary
Jonas Helboe Joergensen, Wei Qiu, Henrik Bruus
Summary: This study investigates acoustic streaming at high acoustic energy densities in a microfluidic channel. The results obtained from theoretical, numerical, and experimental methods demonstrate that frictional heating can significantly alter the streaming pattern at energy densities above 400 J/m3. The study shows that with increasing energy density at a fixed frequency, the traditional boundary-driven four streaming rolls transition into two larger streaming rolls.
PHYSICAL REVIEW LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Madelyn P. Jeske, Wenshi Zhang, Mitchell Anthamatten
Summary: The study demonstrates how combining high-resolution 2PP curing with stimuli-responsive molecular architectures can further the engineering of responsive microstructures and metamaterials.
ADVANCED MATERIALS TECHNOLOGIES
(2022)
Article
Multidisciplinary Sciences
Elaheh Sedghamiz, Modan Liu, Wolfgang Wenzel
Summary: Direct laser writing is an effective technique for fabricating complex 3D polymer networks using ultrashort laser pulses, but obtaining a time-resolved microscopic picture of the printing process in operando remains a challenge. In this study, a molecular dynamics simulation approach is used to model direct laser writing and investigate the effect of writing condition and aspect ratio on the mechanical properties of the printed polymer network.
NATURE COMMUNICATIONS
(2022)
Article
Polymer Science
Martyna Durko-Maciag, Gilles Ulrich, Julien Massue, Jaroslaw Mysliwiec, Konrad Cyprych
Summary: This work demonstrates the successful application of Excited-State Intramolecular Proton Transfer (ESIPT) fluorophores as photoinitiators for microfabrication. The influence of chemical structure on this application was investigated, followed by analysis of two-photon polymerization. The study determined the quality of fabricated structures and polymerization thresholds, with one of the chromophores having an impressively low value of 11 nJ.
EUROPEAN POLYMER JOURNAL
(2023)
Article
Optics
Paul Somers, Zihao Liang, Jason E. Johnson, Bryan W. Boudouris, Liang Pan, Xianfan Xu
Summary: This work combines high-speed projection multiphoton printing with spatiotemporal focusing to achieve rapid, layer-by-layer fabrication of 3D structures. A numerical model for computing spatiotemporal focusing and imaging is presented and verified. Complex 3D structures with smooth features are fabricated, showcasing the potential to manufacture 3D structures with micro/nanoscale features in a practical time scale.
LIGHT-SCIENCE & APPLICATIONS
(2021)
Article
Astronomy & Astrophysics
Felix Karbstein, Ricardo R. Q. P. T. Oude Weernink
Summary: In this study, the nonlinear signature of x-ray vacuum diffraction in the head-on collision of optical high-intensity and x-ray free-electron laser pulses was investigated with finite spatiotemporal offsets between the laser foci. It was found that the angular distribution of the signal in the far-field is sensitive to the wavefront curvature of the probe beam, indicating the potential for improved signal-to-background separation in vacuum birefringence experiments. The pump and probe fields were modeled as pulsed paraxial Gaussian beams, allowing for a reanalysis of the effect from first principles.
Review
Chemistry, Multidisciplinary
Lin Xu, Huanyang Chen
Summary: This paper discusses the method of controlling electromagnetic waves and other wave dynamics through coordinate transformations, and explores the design and application of transformation media. Examples of achieving transformation media by artificially structured units from conventional materials are summarized. These concepts can be extended to control other types of waves, making them useful for multi-physics designs.
ADVANCED MATERIALS
(2021)
Article
Engineering, Manufacturing
Caroline Arnoux, Luis A. Perez-Covarrubias, Alexandre Khaldi, Quentin Carlier, Patrice L. Baldeck, Kevin Heggarty, Akos Banyasz, Cyrille Monnereau
Summary: This paper investigates the proximity effects in additive manufacturing and proposes a parallel write approach to overcome the limitations caused by these effects. Through experiments and computer simulations, the authors successfully model the effects and demonstrate the effectiveness of the parallel write approach in fabricating structures with submicronic inter-object distances.
ADDITIVE MANUFACTURING
(2022)
Article
Acoustics
Lucas Y. M. Sampaio, Pedro C. M. Cerantola, Leopoldo P. R. de Oliveira
Summary: The need for energy-efficient vehicles and machines often leads to the reduction of mass, which in turn affects noise and vibration. Metamaterials, particularly decorated membrane acoustic metamaterials (MAM), have shown promising results in reducing mass and providing efficient attenuation in narrow frequency bands. This study proposes a solution by assembling membranes of different shapes and sizes into a supercell, using tessellation concepts to ensure geometric compatibility and periodicity. Finite element models are used to evaluate sound transmission loss performance of unit cells, which are experimentally validated. Finally, full MAM panels are designed based on the validated models, showing attenuation band formation around the membranes' dominant frequencies and surpassing the mass law.
JOURNAL OF SOUND AND VIBRATION
(2022)
Article
Multidisciplinary Sciences
Curtis Rasmussen, Andrea Alu
Summary: The efficiency and bandwidth of traditional passive acoustic radiators are severely limited, but these constraints can be overcome by loading a piezoelectric transducer with a non-Foster active circuit, resulting in significantly improved radiation bandwidth and efficiency. Experimental results demonstrate a threefold increase in bandwidth, paving the way for non-Foster acoustic radiation technologies.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Chemistry, Multidisciplinary
Filipe A. Couto, Marcelo B. Andrade, Adriano J. G. Otuka, Sebastiao Pratavieira, Sergio R. Muniz, Cleber R. Mendonca
Summary: In this study, we demonstrated a method to incorporate fluorescent nanodiamonds into engineered microstructures using two-photon polymerization. The results show the feasibility of fabricating microstructures embedded within fluorescent nanodiamonds via this method for photonics and quantum technology applications.
Article
Polymer Science
Yulia E. Begantsova, Roman Zvagelsky, Evgeny Baranov, Dmytro A. Chubich, Yuri Chechet, Danila A. Kolymagin, Anastasia Pisarenko, Alexey G. Vitukhnovsky, Sergey A. Chesnokov
Summary: Three imidazole-containing compounds were used as initiators of two-photon polymerization for the first time, and one compound containing phenanthroline combined with triethanolamine showed the best performance in terms of fabrication window, degree of conversion, and two-photon polymerization threshold. This photocomposition was proposed as an effective photoresist for 3D two-photon polymerization, resulting in the fabrication of sub-micron and cell-like polymer structures.
EUROPEAN POLYMER JOURNAL
(2021)
Article
Mathematics
Yan Liu, Xulong Qin, Shuanghu Zhang
Summary: The paper introduces the Blackstock-Cattaneo model based on the Lighthill scheme to describe nonlinear acoustics' propagations with second sound phenomena. It focuses on the mathematical analysis of linear and nonlinear higher-order evolution equations in Rn and investigates the linearized Cauchy problem and global well-posedness of the nonlinear Blackstock-Cattaneo equation.
JOURNAL OF DIFFERENTIAL EQUATIONS
(2022)
Article
Engineering, Multidisciplinary
Christopher Jelich, Wenchang Zhao, Haibo Chen, Steffen Marburg
Summary: This paper presents two fast multipole boundary element formulations for the linear time-harmonic acoustic analysis of finite periodic structures. The efficiency of the methods is demonstrated by subdividing the geometry into boxes and applying a boundary element discretization. The performance of wall-like sound barriers is compared to sonic crystal sound barriers.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2022)
Article
Acoustics
Caglar Gurbuz, Johannes D. Schmid, Marinus Luegmair, Steffen Marburg
Summary: Vibrating structures radiate sound into enclosures, and the location of sound pressure affects the results. The method of surface contributions based on sound energy density is effective in evaluating energy flow.
JOURNAL OF SOUND AND VIBRATION
(2022)
Article
Multidisciplinary Sciences
Karl-Alexander Hoppe, Martin G. T. Kronthaler, Kian Sepahvand, Steffen Marburg
Summary: This study non-destructively identifies non-homogeneous stiffness from noisy measurements of a structural response. The finite element method is used for the discretization of cantilever beam problems, and Karhunen-Loeve expansions represent the stiffness random fields. Bayesian inference is used to solve the inverse problems and introduce a novel resonance frequency method. The results show that static analysis outperforms modal analysis in terms of mean performance, and the quality of the static analysis solution depends on the beam position while the confidence interval remains constant for modal analysis. The static loading procedure yields lower errors than the dynamic procedure for the chosen configuration with ideal boundary conditions.
SCIENTIFIC REPORTS
(2023)
Article
Construction & Building Technology
Shubham Garg, Vasant Matsagar, Steffen Marburg
Summary: Nonlinear finite-element analysis is conducted to study the quasi-static and vibration behavior of prestressed concrete beams strengthened with CFRP laminate. The interaction between concrete and CFRP at the interfaces is accurately modeled using cohesive interface elements, and delamination failure is considered. The study also investigates the effect of prestressing force, tendon location, and profile on the modal frequencies of the strengthened beams. The results show that CFRP-strengthened beams have higher fundamental frequencies and that the modal frequencies vary significantly with tendon location and profile.
STRUCTURAL ENGINEERING INTERNATIONAL
(2023)
Article
Materials Science, Multidisciplinary
Mariia Krasikova, Sergey Krasikov, Anton Melnikov, Yuri Baloshin, Steffen Marburg, David A. Powell, Andrey Bogdanov
Summary: This study develops the concept of a metahouse chamber for multiple band noise insulation, using a ventilated structure based on the idea of metamaterial systems. Broad stop-bands are achieved through strong coupling between pairs of Helmholtz resonators in the structure, demonstrating an averaged transmission attenuation of -18.6 dB within the spectral range from 1500 to 16 500 Hz both numerically and experimentally. The sparseness of the structure and the possibility of using optically transparent materials suggest the potential for partial optical transparency depending on the arrangement of structural elements.
ADVANCED MATERIALS TECHNOLOGIES
(2023)
Article
Acoustics
Jona Eisele, Andre Gerlach, Marcus Maeder, Steffen Marburg
Summary: This paper examines the processing of sensor data for the classification of different object classes and traversability of obstacles using a single ultrasonic sensor. The proposed scalogram-based signal processing chain and convolutional neural network outperforms a LeNet-5-like baseline in accuracy. Several methods for offline and online data augmentation are also presented and evaluated. The obtained accuracies for object classification and obstacle traversability are 90.1% and 66.4% in the laboratory and 96.4% and 91.5% in the outdoor environment, respectively.
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
(2023)
Article
Engineering, Mechanical
Zhe Liu, Feng Wang, Zhixing Cai, Yintao Wei, Steffen Marburg
Summary: The dynamic response of tires affects the vehicle's handling stability and ride comfort. In this study, a new theoretical model is proposed to analyze the dynamic response characteristics of tires on uneven road surfaces, with the advantages of high accuracy and low computational cost.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2023)
Article
Engineering, Mechanical
Andreas Beinstingel, Sebastian Schabert, Michael Heider, Burkhard Pinnekamp, Steffen Marburg
Summary: The acoustics of gearboxes play a crucial role in the success and consumer satisfaction of a gear design. Ensuring quiet operation in special machine engineering is challenging, and a suitable calculation method is essential for finding the optimal design.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2023)
Article
Physics, Applied
Semere B. Gebrekidan, Martin Eser, Marcus Maeder, Steffen Marburg
Summary: This paper investigates the application of self-complementary shapes for sound absorption, aiming to enhance the bandwidth and performance of resonators without changing their sizes and resonance frequencies. Self-complementary shapes show improved absorption performance of up to 58% compared to equivalent circular area resonators when the opening area is reduced. Numerical and experimental analyses are conducted to study the impact of materials, neck length, opening size, and geometry on absorption performance.
APPLIED PHYSICS LETTERS
(2023)
Article
Acoustics
Esmaeel Eftekharian, Paul Croaker, Steffen Marburg, Daipei Liu, Nicole Kessissoglou
Summary: A new method combining the Lighthill source distribution with an acoustic impedance matrix is introduced to determine the contribution of aeroacoustic sources to sound power. The technique is demonstrated by examining the flow noise produced by a pair of co-rotating vortices and comparing the results with Mohring's analogy. The contribution of each component of the Lighthill tensor to sound power is presented for different wave numbers and vortex separation distances. This technique allows for the identification of dominant flow noise sources to sound power.
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
(2023)
Article
Acoustics
Felix Kronowetter, Lisa Pretsch, Yan Kei Chiang, Anton Melnikov, Shahrokh Sepehrirahnama, Sebastian Oberst, David A. Powell, Steffen Marburg
Summary: Arrangements of acoustic meta-atoms, known as acoustic metamaterials, are widely used for acoustic cloaking, field attenuation, and focusing. Understanding the interaction between individual meta-atoms is crucial for improving their collective performance. Numerical studies and experiments reveal that adjusting the coupling and tuning of meta-atoms can mitigate destructive interference, leading to efficient sound attenuation properties.
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
(2023)
Article
Multidisciplinary Sciences
Felix Kronowetter, Marcus Maeder, Yan Kei Chiang, Lujun Huang, Johannes D. Schmid, Sebastian Oberst, David A. Powell, Steffen Marburg
Summary: This study theoretically predicts and experimentally demonstrates the existence of a Friedrich-Wintgen BIC in an open acoustic cavity, providing direct evidence for a QBIC and missing field enhancement data using LDV. A symmetry-reduced BIC design achieves approximately three times field enhancement compared to the original cavity. LDV measurements show promise in obtaining missing field enhancement data for high-Q modes.
NATURE COMMUNICATIONS
(2023)
Article
Acoustics
Jonas M. Schmid, Martin Eser, Steffen Marburg
Summary: Interior acoustic problems require accurate representation of boundary conditions for precise predictions. This study proposes a Bayesian in situ method for estimating the boundary admittance, providing probability distributions for better understanding of uncertainty.
JOURNAL OF THEORETICAL AND COMPUTATIONAL ACOUSTICS
(2023)
Article
Acoustics
Karl-Alexander Hoppe, Kevin Josef Li, Bettina Chocholaty, Johannes D. Schmid, Simon Schmid, Kian Sepahvand, Steffen Marburg
Summary: This study expands the methods for non-destructively identifying material properties of a structure using modal data. It improves the results significantly by using eigenvectors instead of eigenvalues and accelerates the inversion process with a generalized polynomial chaos surrogate. A methodology for reusing surrogate models across inversion tasks is also developed.
JOURNAL OF SOUND AND VIBRATION
(2024)