String instruments are complex mechanical vibrating systems, in terms of both structure and fluid–structure interaction. Here, a review study of the modeling and simulation of stringed musical instruments via the finite element method (FEM) is presented. The paper is focused on the methods capable of simulating (I) the soundboard behavior in bowed, plucked and hammered string musical instruments; (II) the assembled musical instrument box behavior in bowed and plucked instruments; (III) the fluid–structure interaction of assembled musical instruments; and (IV) the interaction of a musical instrument’s resonance box with the surrounding air. Due to the complexity and the high computational demands, a numerical model including all the parts and the full geometry of the instrument resonance box, the fluid–structure interaction and the interaction with the surrounding air has not yet been simulated.

The elastoplastic dynamic mechanical behavior of thin metallic films excited by a nanosecond laser pulse is studied. The dynamic response of the metal films is numerically described by a coupled thermal–structural, transient three-dimensional model based on the finite element method. The developed finite element model takes into account the temperature-dependent true stress–strain curves, the temperature-dependent thermal properties and matters phase changes. Since the numerical simulations include the dynamic changes of the metallic materials mechanical properties, the obtained spatiotemporal numerical solutions provide detailed descriptions of their elastoplastic response. Thus, the experimentally validated model is able to diagnose and predict spatiotemporally matters elastic and plastic deformations that occur during the interaction with a nanosecond laser pulse. Gold, copper, and aluminum thin metallic films are used as test cases to demonstrate the effectiveness of the proposed finite element modeling and simulation.

The evolution of musical instrument manufacturing has prompted a quest for innovative materials beyond traditional wood. This review explores the utilization of composite materials, 3D-printed materials, and metamaterials as favorable alternatives. The investigation is driven by challenges such as the scarcity of high-quality tonewoods, variations in wood properties, and environmental concerns. Carbon fiber, graphite fiber, ceramic polymers, and nanocomposites present promising alternatives, offering advantages in durability, weight reduction, and customizable acoustics. The integration of 3D printing technology introduces a cutting-edge dimension, enabling intricate, precisely engineered components, optimizing instrument structure, and allowing unprecedented customization. Additionally, this article explores metamaterials, leveraging unique mechanical properties from structural design rather than constituent materials. Metamaterials offer unprecedented capabilities for tailoring instrument vibrational characteristics by providing unparalleled control over sound production. The review provides a thorough analysis, including manufacturing methods for composite materials, metamaterials, and 3D printing in musical instruments. Comprehensive examinations of vibrational and acoustical analyses related to composite materials, 3D-printed materials, and metamaterials, for the evaluation of musical instruments, are presented. This overview, supported by experimental and numerical simulation methods, offers valuable insights for the future development of musical instruments.

In this paper, we present a novel scheme for the controlled generation of tunable narrowband γ -ray radiation by ultrarelativistic positron beams inside acoustically driven periodically bent crystals. A novel acoustic crystalline undulator is presented, in which the excitation of a silicon single crystal along the (100) planar direction by a piezoelectric transducer periodically modulates the crystal lattice in the [100] axial direction. An ultrarelativistic positron beam is directed diagonally into the crystal and propagates along the (110) planes. The lattice modulation forces the positrons to follow periodic trajectories, resulting in the emission of undulator radiation in the MeV range. A computational methodology for the design and development of such acoustically based light sources is presented together with the results of simulations demonstrating the favorable properties of the proposed technology. The longitudinal acoustic strains induced in the crystal by high-frequency piezoelectric elements are calculated by finite element simulations. The resulting bending profiles of the deformed crystal planes are used as geometrical conditions for the relativistic molecular dynamics simulations that calculate the positron trajectories and the spectral distribution of the emitted radiation. The results show a strong enhancement of the emitted radiation within a narrow spectral band defined by the bending period, demonstrating the feasibility and potential of the proposed technology.

An integrated method, which combines Electronic Speckle Pattern Interferometry, impulse response measurements, finite element method simulations, and psychoacoustic tests, is proposed to evaluate the vibroacoustic behavior of a carbon fiber bouzouki. Three of the carbon fiber instruments are manufactured, and one is qualified via interferometric experimental measurements with reference to a traditional wooden bouzouki, which was evaluated for its sound and playability by the proposed method. Psychoacoustic tests were used to evaluate the sound and playability of the newly qualified carbon fiber bouzouki, which was further modeled by the finite element method and simulated. The simulation results agreed well with the experimental measurements. Furthermore, finite element simulation results of the qualified carbon fiber bouzouki were demonstrated with reference to the traditional wooden bouzouki experimental results, providing new findings crucial for the optimization of the manufacturing and the vibroacoustic behavior of the carbon fiber instrument. The proposed integrated method can be applied to a variety of carbon fiber stringed musical instruments.

Phononic crystals and acoustic metamaterials are expected to become an important enabling technology for science and industry. Currently, various experimental methods are used for evaluation of acoustic meta-structures, such as impedance tubes and anechoic chambers. Here we present a method for the precise characterization of acoustic meta-structures that utilizes rapid broadband acoustic pulses generated by point-like and effectively massless laser plasma sound sources. The method allows for broadband frequency response and directivity evaluations of meta-structures with arbitrary geometries in multiple sound propagation axes while also enabling acoustic excitation inside the structure. Experimental results are presented from acoustic evaluations of various phononic crystals with band gaps in the audible range, notably also in the very low frequencies, validating the predictions of numerical models with high accuracy. The proposed method is expected to boost research and commercial adoption of acoustic metamaterials in the near future.