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In this paper, a sonification algorithm for developing the off-road models for driving simulators, is proposed. The aim of this algorithm is to overcome difficulties of heuristics identification which are best suited to a particular off-road profile built by measurements. The sonification algorithm is based on the stochastic polynomial chaos analysis suitable in solving equations with random input data. The fluctuations are generated by incomplete measurements leading to inhomogeneities of the cross-sectional curves of off-roads before and after deformation, the unstable contact between the tire and the road and the unreal distribution of contact and friction forces in the unknown contact domains. The approach is exercised on two particular problems and results compare favorably to existing analytical and numerical solutions. The sonification technique represents a useful multiscale analysis able to build a low-cost virtual reality environment with increased degrees of realism for driving simulators and higher user flexibility. [ABSTRACT FROM AUTHOR]

The sound attenuation in a sonic composite without/with point defects is studied using a new method that combines the features of the cnoidal method and the genetic algorithm. Acoustic scatterers are composed by piezoceramic hollow spheres of functionally graded materials-the Reddy and cosine graded hollow spheres. This method enables to obtain the dispersion relation for defect modes, and the prediction of the evanescent nature of the modes inside the band-gaps. [ABSTRACT FROM AUTHOR]

In this paper, the tangential and normal discontinuities at the interface between the scatterer and the matrix are independently modeled, and these relative displacements are directly proportional to the corresponding components of tractions at the interface. The generation of full band-gaps is investigated on the basis of the derived imperfect interface conditions for a sonic plate with an array of acoustic piezoceramic hollow spheres scatterers embedded in an epoxy matrix. The scatterers are made from functionally graded materials with radial polarization. Numerical evaluation has shown that imperfect interface may have a significant effect on the increasing of the length of the full band-gaps. (© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the functionality of a compact robotic system with hybrid kinematic structure, consisting in two hexapods serially connected and controlled in such a way that they have identical configurations any time, in terms of accuracy and maneuverability. By the aid of a demonstration model it was intended to prove that the system substantially benefits of the precision and robustness of the parallel structures and simultaneously is capable to generate complex motions in a significant extended workspace compared with a single hexapod. The double hexapod system answers the actual need of accurate, complex and robust positioning systems used in new technologies and possibly in robotic surgery. [ABSTRACT FROM AUTHOR]

In this paper, a virtual experiment concerning driving on off-roads is investigated via 3D normal vibro-contact problem with friction. The dynamic road concept is introduced in order to characterize a particular stretch of road by total longitudinal, lateral, and normal forces and their geometric distributions in the contact patches. The off-road profiles are built by image sonification technique. The cross-sectional curves of off-roads before and after deformation, the contact between the tire and the road, the distribution of contact and friction forces in the contact domain, the natural frequencies and modes when the tire is in ground contact, are estimated. The approach is exercised on two particular problems and results compare favorably to existing analytical and numerical solutions. The feasibility of image sonification technique is useful to build a low-cost virtual reality environment with an increased degree of realism for driving simulators and higher user flexibility. [ABSTRACT FROM AUTHOR]

Transformation acoustics opens a new avenue towards the architecture, modeling and simulation of a new class of sonic composites with scatterers made of various materials and having various shapes embedded in an epoxy matrix. The design of acoustic scatterers is based on the property of Helmholtz equations to be invariant under a coordinate transformation, i.e., a specific spatial compression is equivalent to a new material in a new space. In this paper, the noise suppression for a wide full band-gap of frequencies is discussed for spherical shell scatterers made of auxetic materials (materials with negative Poisson's ratio). The original domain consists of spheres made from conventional foams with positive Poisson's ratio. The spatial compression is controlled by the coordinate transformation, and leads to an equivalent domain filled with an auxetic material. The coordinate transformation is strongly supported by the manufacturing of auxetics which is based on the pore size reduction through radial compression molds. [ABSTRACT FROM AUTHOR]

Transformation acoustics opens a new avenue towards the fabrication of a new class of sonic composites with scatterers made of auxetic materials embedded in the epoxy matrix. The design of the acoustic scatterers is based on the property of Helmoltz equations to be invariant under coordinate transformations, i.e. a specific spatial compression is equivalent to a variation of the material parameters in the original space. In this paper, the noise suppression for a wide full band-gap of frequencies is discussed for spherical shell scatterers made of auxetic materials. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]