Sound Vibr Research Articles

Soundiation: A software in evaluation of acoustophoresis driven by radiation force and torque on axisymmetric objects.

Acoustic radiation force and torque arising from wave scattering are commonly used to manipulate micro-objects without contact. We applied the partial wave expansion series and the conformal transformation approach to estimate the acoustic radiation force and torque exerted on the axisymmetric particles. Meanwhile, the translational and rotational transformations are employed to perform the prediction of the acoustophoresis. Although these theoretical derivations are well-developed [Tang and Huang, J. Sound Vibr. 532, 117012 (2022), Tang and Huang, Phys. Rev. E 105, 055110 (2022)], coding the required systems, including generation of the wave function, implementation of the transformations, calculations between modules, etc., is non-trivial and time-consuming. Here, we present a new open-source, matlab-based software, called Soundiation [GitHub Repository: https://github.com/Tountain/SoundiationAcoustophoresis, GPL-3.0 license], to address the acoustic radiation force and torque while supporting the dynamic prediction of non-spherical particles. The implementation is basically generic, and its applicability is demonstrated through the validation of numerical methods. A graphical user interface is provided so that it can be used and extended easily.

Global modes for the reduction of flexible multibody systems

Modeling a flexible multibody system employing the floating frame of reference formulation (FFRF) requires significant computational resources when the flexible components are represented through finite elements. Reducing the complexity of the governing equations of motion through component-level reduced-order models (ROM) can be an effective strategy. Usually, the assumed field of deformation is created considering local modes, such as normal, static, or attachment modes, obtained from a single component. A different approach has been proposed in Cammarata (J. Sound Vibr. 489, 115668, 2020) for planar systems only and involves a reduction based on global flexible modes of the whole mechanism. Through the use of global modes, i.e., obtained from an eigenvalue analysis performed on the linearized dynamic system around a certain configuration, it is possible to obtain a modal basis for the flexible coordinates of the multibody system. Here, the same method is extended to spatial mechanisms to verify its applicability and reliability. It is demonstrated that global modes can be used to create ROM both at the system and component levels. Studies on the complexity of the method reveal this approach can significantly reduce the calculation times and the computational effort compared to the unreduced model. Unlike the planar case, the numerical experiments reveal that the system-level approach based on global modes can suffer from slow convergence speed and low accuracy in results.

Time Varying Loads and White Noise on an SDOF System with Bouc Hysteresis Using Gaussian Closure

In a recent publication [H. Waubke and C. Kasess, Gaussian closure technique applied to the hysteretic Bouc model with nonzero mean white noise excitation, J. Sound Vibr. 382 (2016) 258–273], the response of a single-degree-of-freedom (SDOF) system under Gaussian white noise and a constant dead load is presented. The system has a hysteresis described by Bouc [R. Bouc, Forced vibration of mechanical systems with hysteresis, in Proc. Fourth Conference on Nonlinear Oscillation (Prague, 1967), p. 315]. New is the usage of a slowly time-varying deterministic load added to the Gaussian white noise process. The transient solution is calculated using the Gaussian closure technique together with an explicit time step procedure. All moments in the Gaussian closure technique are evaluated analytically. The results of the Gaussian closure technique are in good agreement with the results from the Monte-Carlo method.

T-matrix method implementation for acoustic Bessel beam scattering from elastic solids and shells

T-matrix method (TMM) has been demonstrated to be an effective tool for the application of acoustic Bessel beam (ABB) scattering from rigid shapes, owing to the fact that the incident ABBs could be appropriate to expand on the basis of spherical harmonics [Gong et al., J. Sound Vibr. 383, 233-247 (2016)]. In this work, we try to extend the TMM to further calculate ABB scattering from complicated elastic shapes, spheroids/ spheroidal shells for instance. Some numerical techniques are successfully implemented to overcome the instability problem during matrix inversion procedures for nonspherical shapes. Resonance scattering theory and ray theory [Kargl and Marston, J. Acoust. Soc. Am. 88, 1103-1113 (1990)] are employed to explore and interpret several novel properties of scattering from elastic shapes illuminated by ABBs, thus revealing the corresponding mechanism of scattering by ABBs. Furthermore, the present work will perform as a foundation work to extend the applicability of TMM to study acoustic radiation force and torque in ABBs in future. [Work supported by NSFC.]

Substructural Condition Assessment Based on Force Identification and Interface Force Sensitivity

Time domain substructural condition assessment method is actively researched in recent years to avoid the problem with uncertainties in the different components of the structure, boundary conditions and with an improved effort in the inverse computation. Since the interface force between substructures would vary with the existence of local damages and excitation in the substructures, existing condition assessment method for a full structure cannot be applied directly to the substructures. Also, most existing approaches adopt the state space method in the response prediction. However, the state space method can be shown in this paper inaccurate in the forward substructural dynamic analysis due to the discretization error, and therefore identification based on this method cannot give satisfactory result for a substructure. The force identification for a full structure based on the explicit Newmark-β method has been shown superior to the state space method [K. Liu et al., J. Sound Vibr.33(3) (2014) 730–744]. This method is extended in this paper for substructural interface force identification. The variation of interface forces between substructures with variation in the substructural condition is illustrated with a plane truss structure. Subsequent condition assessment based on substructural response sensitivity is proposed with the analytical derivation of the sensitivity taking into account the interface force sensitivity which is not small to be ignored. The new damage detection method based on the explicit Newmark-β method and the substructural response sensitivity is verified numerically with different damage scenarios in a plane truss structure giving satisfactory results.

Retraction notice to: “Flap side edge noise modeling and prediction” [J. Sound Vibr. 332 (2013) 3846–3868

Retraction notice to: “Flap side edge noise modeling and prediction” [J. Sound Vibr. 332 (2013) 3846–3868

Corrigendum to “Damping performance of two simple oscillators coupled by a dissipative connection” [J. Sound Vibr. (2014) 2359–2377

Corrigendum to “Damping performance of two simple oscillators coupled by a dissipative connection” [J. Sound Vibr. (2014) 2359–2377

Drill-string vibration analysis using non-smooth dynamics approach

In this work, we model and analyse drill- string vibrations. A special attention is paid to stick- slip and bit-bounce behaviours that are normally treated as the non-smooth dynamics. A two degrees- of-freedom lumped parameters model is employed to account for axial and torsional vibrations based on the model proposed by Christoforou and Yigit (J. Sound Vibr. 267:1029-1045, 2003). The coupling between both vibration modes is through contact with the for- mation, where the axial force is the catalyst to gener- ate a resistive torque. The forces and torques are de- fined according the contact or non-contact scenarios, establishing a non-smooth system. Besides, the dry friction between the formation and the drill-bit intro- duces the other non-smoothness of the system. Here we adopt smoothened governing equations which are advantageous in terms of mathematical description and numerical analysis. Our studies have shown that the mathematical model is capable of predicting a full range of dynamic responses including the stick-slip and drill bit-bounce. A global analysis shows differ- ent scenarios related to parameter changes allowing to develop an in depth understanding of the drill-string dynamics and define critical behaviours of the sys- tem.

Determination of stress and displacement state in the circular annulus steel sheet with Cartesian orthotropy

This paper deals with determination of stress, strain and displacement state of a circular annulus which is made of material with Cartesian orthotropic rheological behaviour. There is a continuous and constant load on the inner and/or outer edge. Stress and strain state in the circular annulus is in the elastic domain. Stress state is determined on the basis of an Airy stress function, where all boundary conditions have to be fulfilled. The Ritz's method was applied to determine unknown parameters of the Airy function. References F. Kosel. The stress and deflection state in the circular annulus with Cartesian orthotropy. Proceedings 14th Canadian Congress of Applied Mechanics , volume 2, pages 493--494. CANCAM, 1993. Pistonesi, C. and Laura, P. A. A., Forced vibrations of a clamped, circular plate of rectangular orthotropy, J. Sound Vibr. , 228 , 1999, 712--716. Tahan, N., PavloviE, M. N. and Kotsovos, M. D., Orthotropic rectangular plates under in-plane loading part 1: closed-form solutions for stresses, Compos. Struct. , 33 , 1995, 35--48. Wu, Z. J. and Wardenier, J., Further investigation on the exact elasticity solution for anisotropic thick rectangular plates, Int. J. Solids Struct. , 35 , 1998, 747--758. Adewale, A. O., Application of the singularity function method to semi-infinite orthotropic rectangular plates on an elastic foundation, Int. J. Mech. Sci. , 43 , 2001, 2261--2279. Bhaskar, K. and Kaushik, B., Simple and exact series solutions for flexure of orthotropic rectangular plates with any combination of clamped and simply supported edges, Compos. Struct. , 63 , 2004, 63--68. S. G. Lekhnitskii. Theory of elasticity of an anisotropic body . Mir Publishers, Moscow, 1981.

Measuring the Young’s modulus of reeds from American reed organs.

A method of wave coefficients has been used to measure the Young’s modulus of brass reeds from American reed organs. Although for some purposes these reeds can be approximated as uniform cantilever beams, their cross sections are sufficiently nonuniform that simple methods such as measuring beam displacement for a known applied force or using resonant frequencies of transverse and torsional modes of vibration are not sufficient to obtain accurate results. In the wave coefficient method [Y. Liao and V. Wells, J. Sound Vibr. 295, 165–193 (2006)] a wave number is found that forces data at all measurement points to conform to the general forced-vibration solution for a beam, implying that they have the same wave coefficients. This method also assumes a uniform cross section but does not require measurements along the entire length of the beam and was applied only to the most uniform sections of the reeds. Three reeds of the same frequency were selected, with cross sections of varying uniformity. The resulting measurements of the Young’s modulus seemed consistent with expected values for brass. For one reed with nearly uniform cross section the wave coefficient method was in good agreement with the simpler methods.

Transmission and localization in connected ergodic reverberation rooms

The wave power redistribution in two connected reverberant structures represents a paradigm problem in studies of transmission through a complex structure consisting of several reverberant substructures. We analyze randomly coupled ergodic reverberation rooms with the goal to extend such analysis to a more general situation. The two-room problem is, however, quite challenging on its own [R. L. Weaver and O. I. Lobkis, J. Sound Vibr. 231, 1111–1134 (2000)]. Although the ergodicity assumption allows one to use random matrix theory (RMT), by describing both subsystems with random Gaussian Hamiltonians, the nonperturbative calculations of power transmission and localization have not yet been done. The only attempt made in this direction was the corresponding study of two coupled quantum dots [A. Tschersich and K. B. Efetov, Physi. Rev. E 62, 2042–2045 (2000)], which used the supersymmetry technique to calculate the joint distribution of local densities of electron wavefunctions and found spatial correlations absent in a single chaotic system. Here, we present both perturbative and nonperturbative (in ensemble averaging) RMT calculations of simplest nontrivial characteristics of power transmission and localization, and compare it with numerics.

Numerical simulation of an aircraft style panel excited by a random pressure field

This study describes the development of a model that predicts the sound radiation from an aircraft style panel excited by a dynamic pressure field with arbitrary spatial correlation. Eventually, this model will be used to develop distributed feedback control strategies for systems with spatially correlated inputs. For this study, the input pressure field is simulated using an array of point forces on the panel. The excitation at each point is defined in the time domain using the spectral representation method [M. Shinozuka and C.-M. Jan, J. Sound Vibr. 25(1), 111–128 (1972)]. This method generates sample functions that match the spatial and temporal correlation characteristics of the desired pressure field. Three different types of excitations are considered: a turbulent boundary layer excitation, a diffuse field, and a spatially uncorrelated disturbance. This approach could be extended to a variety of other types of spatially correlated stochastic inputs as well. A convergence study is also presented to show how many point forces are required to approximate the spatial characteristics of each type of pressure field. [Work supported by NASA.]

Response of a two degrees of freedom articulated tower to different environmental conditions

In a previous paper [ J. Sound Vibr. (1996)], the response of an articulated tower in the ocean subjected to deterministic and random wave loading was investigated. The tower was modeled as an upright rigid pendulum with a concentrated mass at the top and having one angular degree of freedom about a hinge with coulomb damping. In this paper, which is an extension of the previous one, the tower is modeled as a spherical pendulum having two angular degrees of freedom. The tower is subjected to wave, current, vortex shedding, wind and Coriolis acceleration loads. Geometrical non-linearities as well as non-linearities due to wave drag force, which is assumed to be proportional to the square of the relative velocity between the tower and the waves, were considered. The governing coupled differential equations of motion are highly non-linear, and have time-dependent coefficients. The tower's response to the external forces is found, that is, equilibrium position due to wind and current and response to wave excitation. Resonances (harmonic and subharmonic) and also chaotic response are investigated.

Recurrent integration of beam functions

Felgar's recurrence formula for ∝ θφ dξ was corrected by the author recently. While the new formulae are correct, the table quoted from Gartner and Olgac [ J. Sound Vibr. 34, 481–489 (1982)] for the integration constants is found to be incorrect. Because of the importance of the correctness of the admissible comparison functions in a Rayleigh-Ritz analysis, the formulae are rederived with detailed immediate steps, so that a cautious user may check for any possible errors, including printing errors, before implementation. Methods to generate the coefficients of the formulae are discussed and a computer program for the integration by parts many times is given.

135. Response of an accelerating vehicle to random road undulation: V.J. Virchis and J.D. Robson. J. sound vibr.18, no. 3, 423–427 (October 1971)

135. Response of an accelerating vehicle to random road undulation: V.J. Virchis and J.D. Robson. J. sound vibr.18, no. 3, 423–427 (October 1971)