Hao-Wen Dong

Beijing Institute of Technology | BIT · Institute of Advanced Structure Technology

Aiming at the promising superlensing for the medical ultrasonic and detection, the double-negative metamaterials which possess the negative mass density and elastic modulus simultaneously can be acted as the ideal superlens for breaking the diffraction limit. In this paper, we use topology optimization to design the two-dimensional single-phase ani...

Acoustic negative-index metamaterials show promise in achieving superlensing for diagnostic medical imaging. In spite of the recent progress made in this field, most acoustic metamaterials (AMMs) suffer from deficiencies such as low spatial symmetry, sophisticated labyrinth topologies and narrow-band features, which hamper their applications for sy...

Pentamode metamaterials (PMs), a kind of metafluids composed of complex solid medium, have shown enormous potential for both elastic wave and underwater acoustic wave manipulation. However, due to the lack of thorough understanding of the formation mechanism, most reported artificial and empirical PMs share very similar topological features, thus d...

Metasurfaces, the ultrathin media with extraordinary wavefront modulation ability, have shown great promise for many potential applications. However, most of the existing metasurfaces are limited by narrow-band and strong dispersive modulation, which complicates their real-world applications, which usually require strict customized dispersion. To a...

Flexible manipulation of elastic and acoustic waves through phononic meta-structured materials (PMSMs) has attracted a lot of attention in the last three decades and shows a bright future for potential applications in many fields. Conventional engineering design methods for PMSMs rely on changing the material composition and empirical structural co...

Acoustic metasurfaces are widely used for noise attenuation due to their outstanding acoustic performance and subwavelength characteristics. The paper introduces a topology-optimized inverse design approach for broadband sound-absorbing metasurfaces, aiming to achieve efficient sound absorption performance across a wide frequency spectrum. By integ...

Extremely large acoustic impedance mismatching generates a natural acoustic barrier at the air-water interface, resulting in significantly impeding bidirectional acoustic wave propagation across the heterogeneous interface. Here, an air-water metasurface with dual coupling resonators is proposed to enhance the acoustic transmission at the air-water...

Underwater acoustic metamaterials have provided new ideas for underwater acoustic stealth of various underwater vehicles. However, the existing sound absorption performances are still limited by the intuitive design or geometry-only optimization. To systematically construct the low-frequency broadband underwater absorbing metamaterials under rigoro...

Quasi-zero-stiffness (QZS) isolators have been demonstrated to realize low-frequency vibration isolation without loss of static stiffness. However, most previous designs are based on spring-driven links, cam-roller structures, or two-phased network structures resorting to complex assembling components, other than compact and integrative single-phas...

The paper introduces a novel method for simulating acoustic–shell interaction subject to seabed reflection. The vibration of thin-shell structure is analyzed using the finite element method (FEM) with Kirchhoff–Love shell elements. Exterior acoustic fields associated with seabed reflection is simulated by the boundary element method (BEM) with half...

In this paper, we develop tunable reflection-type broadband acoustic coding metasurfaces (BACMs) using a bottom-up topology optimization method. These metasurfaces enable flexible configuration switching between the antiphase coding units of “0” and “1” across a wide frequency range through electromagnetic regulation. By introducing a customized di...

The acoustic coding metasurfaces (ACMs) have the ability to manipulate complex acoustic behavior by reconstructing the coding sequence. In particular, the design of broadband coding enhances the versatility of ACMs. ACMs offer significant advantages over traditional metasurfaces, including a limited number of units and flexible wave control perform...

Acoustic vortices carrying orbital angular momentum are significant in wave-matter interactions, allowing for versatile devices with promising applications. However, current metasurface-based vortex generators have limited bandwidth, operating within a narrow frequency range. Here, we propose a broadband acoustic metasurface with four space-coiling...

In this paper, a kind of broadband elastic wave coding metasurfaces is proposed. The metastructure unit designed by topology optimization is used as logical unit “1,” and the pure plate is set as logical unit “0.” The phase difference of the transmitted longitudinal wave between two units is introduced as the objective function in optimization. The...

Unlike the holography technique using active sound source arrays, metasurface-based holography can avoid cumbersome circuitry and only needs a single transducer. However, a large number of individually designed elements with unique amplitude and phase modulation capabilities are often required to obtain a high-quality holographic image, which is a...

We construct a reflective broadband acoustic coding metasurface using bubbles as the unit. The reflected phase difference between the cube bubble unit and the pure water unit is about π over a wide frequency range. The broadband phenomenon could be explained by the reflection theory between the soft water-air interface and the hard water-rigid inte...

Existing solid composite structures composed of several viscoelastic materials and metals mainly exploit diverse resonances, damping, and scattering to realize underwater acoustic wave functionalities. However, low-frequency broadband underwater sound absorption and insulation are still hard to capture with an acoustic coating possessing subwavelen...

During the past decade, the passive metasurfaces enabling vortex beams carrying orbital angular momentum have drawn great interest in the fields of electromagnetic and acoustic wave. In the underwater environment, however, the elastic metasurface with a certain bandwidth is more difficult to be realized due to the strong fluid-solid interaction and...

Achieving broadband low-frequency surface wave bandgaps is technically challenging, which calls for a systematic design paradigm instead of intuitive approaches. In this study, we use topology optimization to design seismic metamaterials (SMMs) for achieving maximum surface wave bandgaps in the typical frequency range of seismic waves (1∼20 Hz) whi...

Broadband effectiveness and impedance mismatching in fluid-structure coupling remain significant obstacles in the pursuit of broadband high-efficient high-symmetrical subwavelength underwater acoustic devices using metamaterials. Here, we propose a kind of mode metamaterials and integrate them into a gradient metalens for the broadband, high-effici...

Unlike their electromagnetic and acoustic counterparts, elastic waves involve different wave modes. The interplay and the coupling among them increase the complexity of the problem while also offering a larger space for wave manipulation. Elastic bulk wave conversion in an elastic metamaterial has recently shown great promise in medical ultrasound...

Lamb waves inside thin-walled structures have received extensive attention due to their great promise in applications such as structural health monitoring. Applications point at the common need for effective conditioning and manipulation of the wave propagation in terms of both frequency content and mode components. In this work, the concept of met...

In this paper, we propose a kind of reflection-type broadband acoustic coding metasurfaces (BACMs), which are composed of two square helical channels and the connected air cavity at the end of the channels. This helical-cavity coupled structure is selected as a logical unit “1,” the pure air hole is set as a logical unit “0,” and the reflective pha...

Due to their limited number of units but outstanding ability to control rather complex wave-propagation phenomena, acoustic coding metasurfaces (ACMs) as two-dimensional metamaterials show a stronger competitiveness in metamaterial applications. However, hindered by their narrow-band modulation capability, the previously reported ACMs do not exhibi...

Elastic waves are typical motion forms of engineering symmetric and asymmetric structures. The mechanical vibration of major equipment, such as large spacecraft/aircraft, underwater vehicles, precision machine tools, etc., is essentially the superposition of elastic waves inside their structural components. The studies of elastic wave propagation a...

To control wave propagation in phononic crystals (PnCs), it is crucial to perform the inverse design of dispersion engineering. In this article, a robust deep-learning method of dispersion engineering in two-dimensional (2D) PnCs is developed by combining deep neural networks (DNNs) with the genetic algorithm (GA), which can be easily extended to r...

No PDF available ABSTRACT The recent development of acoustic metasurfaces has broadened the capabilities of wave engineering devices with a compact profile. However, the application of acoustic metasurfaces in many scenarios has been limited by their bandwidths. In this work, we report the realization of broadband acoustic metasurfaces that deliver...

Dispersion engineering is always the important topic in the field of artificial periodic structures. In particular, topology optimization of composite structures with expected bandgaps plays a key role. However, most reported studies focused on topology optimization for bulk waves, and the optimization for surface wave bandgaps (SWBGs) is still mis...

Metasurfaces, the ultrathin media with extraordinary wavefront modulation ability, have shown versatile potential in manipulating waves. However, existing acoustic metasurfaces are limited by their narrow-band frequency-dependent capability, which severely hinders their real-world applications that usually require customized dispersion. To address...

Dirac point, the cornerstone of topological insulators, has been attracting ever-increasing attention due to its extraordinary properties. In this paper, a bottom-up topology optimization approach is established to systematically design the acoustic Dirac cones with customized double, triple and quadruple degeneracies at different wavelength scales...

Acoustic negative-index metamaterials show promise in achieving superlensing for diagnostic medical imaging. In spite of the recent progress made in this field, most metamaterials suffer from deficiencies such as low spatial symmetry, sophisticated labyrinth topologies and narrow-band features, which make them difficult to be utilized for symmetric...

Acoustic negative-index metamaterials show promise in achieving superlensing for diagnostic medical imaging. In spite of the recent progress made in this field, most metamaterials suffer from deficiencies such as low spatial symmetry, sophisticated labyrinth topologies and narrow-band features, which make them difficult to be utilized for symmetric...

Double-negative acoustic metamaterials (AMMs) offer the promising ability of superlensing for applications in ultrasonography, biomedical sensing and nondestructive evaluation. However, the systematic design and realization of broadband double-negative AMMs are stilling missing, which hinder their practical implementations. In this paper, under the...

Acoustic metamaterials (AMMs) with negative parameters enable novel ways of focusing and shaping wave fields at subwavelength scales. Double-negative AMMs offer the promising ability of superlensing for applications in ultrasonography, biomedical sensing and nondestructive evaluation. However, the systematic design and realization of broadband doub...

Double-negative acoustic metamaterials (AMMs) offer the promising ability of superlensing for applications in ultrasonography, biomedical sensing and nondestructive evaluation. Here, under the simultaneous increasing or non-increasing mechanisms, we develop a unified topology optimization framework considering the different microstructure symmetrie...

Hyperbolic metamaterials, the highly anisotropic subwavelength media, immensely widen the engineering feasibilities for wave manipulation. However, limited by the empirical structural topologies, the reported hyperbolic elastic metamaterials (HEMMs) suffer from the limitations of the relatively narrow frequency width, inflexible adjustable operatin...

Double-negative acoustic metamaterials (AMMs) offer the promising ability of superlensing for applications in ultrasonography, biomedical sensing and nondestructive evaluation. However, the systematic design and realization of broadband double-negative AMMs are stilling missing, which hinder their practical implementations. In this paper, under the...

Hyperbolic metamaterials are strongly anisotropic artificial composite materials at a subwavelength scale and can greatly widen the engineering feasibilities for manipulation of wave propagation. However, limited by the empirical structure topologies, the previously reported hyperbolic elastic metamaterials (HEMMs) suffer from the limitations of re...

We study theoretically the simultaneous existence of large phononic and photonic bandgaps in chiral phoxonic crystals by topology optimization. By analyzing the effect of the chiral symmetry with different material orientations in both the square and triangular lattices, we discuss the most suitable structural properties for opening large phononic...

Topology optimization of a waveguide-cavity structure in phononic crystals for designing narrow band filters under the given operating frequencies is presented in this paper. We show that it is possible to obtain an ultra-high-Q filter by only optimizing the cavity topology without introducing any other coupling medium. The optimized cavity with hi...

Topology optimization of a waveguide-cavity structure in phononic crystals for designing narrow band filters under the given operating frequencies is presented in this paper. We show that it is possible to obtain an ultra-high-Q filter by only optimizing the cavity topology without introducing any other coupling medium. The optimized cavity with hi...

In this paper we present a comprehensive study on the multi-objective optimization of two-dimensional porous phononic crystals (PnCs) in both square and triangular lattices with the reduced topology symmetry of the unit-cell. The fast non-dominated sorting-based genetic algorithm II is used to perform the optimization, and the Pareto-optimal soluti...

By using the nondominated sorting-based genetic algorithm II, we study the topology optimization of 2D phoxonic crystals (PxC) with simultaneously maximal and complete photonic and phononic bandgaps. Our results show that the optimized structures are composed of solid lumps with narrow connections, and their Pareto-optimal solution set can keep a b...

By using the finite element method and a “coarse to fine” two-stage genetic algorithm as the forward calculation method and the inverse search scheme, respectively, we perform both the unconstrained and constrained optimal design of the unit cell topology of the two-dimensional square-latticed solid phononic crystals (PnCs), to maximize the relativ...

In this paper, we show that it is possible to design two-dimensional (2D) porous phononic crystals (PnCs) with a simultaneously maximal bandgap width (BGW) and the minimal mass through multi-objective optimization (MOOP) by using the non-dominated sorting-based genetic algorithm II. Compared with the single-objective optimization, the optimized str...

Phononic crystals (PnCs) can be designed to control and confine elastic waves. We present and use the optimization algorithm based on the two-stage genetic algorithm (GA) and the finite element method (FEM) to carry out the band gap optimization of the two-dimensional (2D) solid-solid binary-component PnCs.

The band gap optimization of the two-dimensional solid PNCs is studied. The finite difference time domain method and the genetic algorithm are used as the forward calculation method and optimization scheme, respectively. Some preliminary numerical results are presented.