Documentation > SonicByte^TM

SonicByte^TM- "Why continue to lose up to 1000$ a minute for the problems of premature failure of materials in your process while their original defects can now be detected in less than 15 seconds?"

The SonicByte^TM technology, co-developed by Dr. Claude Allaire, makes NDT (Non Destructive Testing) applicable both to homogenous (ex.: metals and ceramics) and heterogeneous (ex.: refractories and carbon products) materials, at room and high temperature.

SonicByteTM
Manual version Automated version

Background and operational principles
Dr. Claude Allaire, co-inventor, and his team of scientists are working since 2003 on developing a new non-destructive control apparatus for heterogeneous materials. The development of this new apparatus, called SonicByte^TM, was to counter the limitations associated with the existing apparatus available on the market using the acoustic resonance technique.
The principle of this technique consists in making a material vibrate with low intensity mechanical impacts and to measure the vibration frequencies to extract the acoustic constants such as the elastic modulus (Young’s modulus).
However, the apparatus then available on the market were applicable only to homogeneous materials such as metals and fine ceramics having a simple geometry.
The first prototype, developed in 2003, allowed not only to characterize these same materials, but also heterogeneous materials such as refractories, construction concretes and carbon materials. However, this first apparatus was only applicable at laboratory scale for the characterization of small simple geometry samples such as bars, cylinders or discs. In 2004, a new version of the apparatus was developed for quality control of industrial heterogeneous materials. This new version allowed the determination of elastic constants of such materials, independently of their shape and size, but was limited to simple geometries. In 2005, a new technique was integrated to the apparatus making also possible to characterize the defects found in such materials. In 2006, additional R&D works were undertaken with the goal of making the apparatus capable of characterizing the defects found in material with complex geometry, such as products of poured cast iron and steel, maximizing therefore the range of possible applications of our technology.
Heterogeneous materials elastic properties
The knowledge about the elastic properties of materials is of the outmost importance. These properties not only reflect the importance of bonding within the material, but also allow the characterization of its extent of damage. These properties therefore become an essential tool for material manufacturers to control the quality of their products, consequently contributing in lowering their manufacturing costs and the number of claims, while allowing them to better positioning themselves against the competition.
The methods of non-destructive characterization derived from acoustics are frequently used to characterize homogeneous materials such as metals or fine ceramics of simple geometry. The applications of such methods when analysing heterogeneous materials and/or of complex geometry present some difficulties. In fact, the nature of these materials favours acoustic attenuation phenomena and leads to the appearance of multiple resonance frequencies that considerably interfere with the signal’s interpretation, making it often impossible with traditional apparatus.
In the case of metals, others non-destructive characterization techniques are available such as infrared radiation, Eddy currents, ultrasounds and penetrating liquids. These techniques are however not very efficient for the quality control of large and/or complex geometric pieces taking into account their high execution time.
The SonicByte^TM uses an innovative technology enabling it to counter these difficulties and therefore makes it suitable for quality control of materials, regardless of their nature, their size and geometry.
Principle of the acoustic methods used by SonicByte^TM

Acoustic resonance
The characterization acoustic methods are based on the study of mechanical deformation waves, or vibrations, that propagate through the matter. In solids, sound can propagate through longitudinal or transverse waves. When an elastic material suffers a soft impact, it enters in resonance at a fondamental frequency that depends on its elastic properties, i.e., the Young’s (or elastic) modulus, the Coulomb’s (or shearing) modulus and the Poisson’s ratio. To determine these constants, we generally use an analytical approach. With the help of equations derived from such an approach, it is possible to determine each elastic constant by measuring a minimum of three (3) resonance frequencies which are associated to the longitudinal, the flexural and the torsional propagation mode of the piece to analyse. For pieces with complex geometry, these elastic constants are obtained by numerical analysis. By using reference pieces, it becomes possible from these constants to detect the presence of the defects contained inside the analysed piece.
Non linear acoustic
Unlike homogeneous materials, heterogeneous materials present a nonlinear acoustic behaviour. Their resonance frequency after impact is in fact not achieved instantly but after a short time during which their frequency gradually increases. This is because at the time of impact, the elastic energy available in the material is usually sufficient to cause the vibration of all its defects, regardless of their size. Over time, attenuation phenomena gradually reduce the energy available to cause the vibration of the smaller defects. Measuring the frequency at instant of impact and that of the constant frequency settling eventually allow therefore to characterize the size distribution of defects in the material.
Acoustic attenuation and dispersion
Acoustic waves are more attenuated in a material when it contains inhomogeneities such as microcracks. The latter also promote, after impact, the generation of a frequencies range around the resonance frequency. Quantifying the dispersion of the latter and its attenuation allow comparing the damage level of the tested piece to that of a reference piece.
Acoustic signature
Materials with complex geometry tend to generate multiple frequencies after impact. In such cases, the acoustic method most appropriate to characterize their defects is generally the acoustic signature. This method involves collecting the spectral amplitude distribution of the analyzed piece and to compare it with that of a reference piece. Then, the observed differences between the two distributions can be associated to the different types of defects contained inside the analysed piece.
Critical defects size, porosity and mechanical resistance characterization using SonicByte^TM
The SonivByte^TM has an algorithm to determine the average length of the critical defects contained inside the analyzed piece. By definition, the critical defects are those that limit the structural strength of the piece. Let us consider the following figure:

The schematized "real" cylindrical piece shown on this figure contains a geometric discontinuity, non uniformly distributed defects (suchs as cracks) and uniformly distributed defects (such as pores). The structural mechanical resistance of that piece is equal to that of the "equivalent" piece (shown on the right) inside which all non uniformly distributed defects of the real piece are replaced by a peripheric and central critical crack of average lenght "a_c". The equivalent piece diameter is reduced compared to that of the real piece to make equal their average cross-section area. The elastic modulus of the equivalent piece is equal to the theoretical elastic modulus "E₀", which corresponds to the elastic modulus of the real piece if it was containing only uniformly distributed defects. The values of "a_c" and "E₀" are determined mathematically from the measured E_L and E_Fvalues, which represent the elastic moduli of the real piece, either in longitidinal or flexural modes, respectively. It should be noted that in absence of non uniformly distributed defects inside the real piece; E_L= E_F= E₀.
From the values of "a_c" and "E₀", the SonicByte^TM algorithm allows the estimation of the analysed piece's porosity as well as its mechanical resistance, i.e., the tensile strength for metals and the modulus of rupture and the compressive strength for ceramics and refractories. However, these estimations require that these same properties as well as the "a_c" and "E₀" values be known for a reference piece (See: Example for the case of refractories).
A similar procedure is applicable for pieces having a prismatic section. In this case, the values of "a_c" and "E₀" are obtained from the measured values of E_F1and E_F2, which correspond to the elastic moduli of the real piece in flexural mode and under two orthogonal and perpendicular orientations with respect to its longitudinal axis. It should be noted that with this type of geometry, the section reduction of the equivalent piece compared to that of the real piece is for making equal their flexural inertia moment.

For additional information
→ See: Examples of works conducted in plant and in laboratory with SonicByte^TM.

SonicByteTM - "Why continue to lose up to 1000$ a minute for the problems of premature failure of materials in your process while their original defects can now be detected in less than 15 seconds?"

SonicByte^TM- "Why continue to lose up to 1000$ a minute for the problems of premature failure of materials in your process while their original defects can now be detected in less than 15 seconds?"