This paper describes the investigation for the feasibility of inspection of steel-rocasin rubber specimen used in rocket motor for detection of debond by using air-coupled ultrasonic. A pair of high performance air-coupled transducers was used to generate and receive the high intensity ultrasonic pulses. Probes were placed at the opposite side of the specimen during inspection. It was shown tha...

This paper aims the studying, modeling and testing of models of linear motors which use ultrasonic waves to achieve the movement. The studied motors are characterized by the positioning accuracy, small inertia, wide speed control (does not require gears and gearboxes), easy control, high torque per unit weight, miniaturization, simple structure, low noise, decreasing time-speed characteristic. ...

introduction: the aim of this experimental laboratory study was to evaluate the effect of different mixing and placement techniques on compressive strength (cs) of calcium-enriched mixture (cem) cement. methods and materials: cem powder was mixed with its liquid either by hand mixing or amalgamator mixing. the mixture was loaded to cylindrical acrylic molds with 6.0±0.1 mm height and 4.0±1 mm d...

A method for ultrasonic measurement of friction material elastic constants was evaluated through a round-robin process. The purpose of the study was two-fold: 1) to formulate and evaluate a standard test method (SAE J2725) for measuring elastic constants using ultrasound and 2) to quantify the measurement variability when the testing method is applied by multiple operators and instrumentation. ...

Non Destructive testing of structural materials is an important activity in many industries. Ultrasonic NDT is one such method widely used in this field. Pulse Echo and Through Transmission are conventional testing techniques which use reflected and transmitted sound energy respectively. But these techniques are highly dependent on defect orientation. Time of Flight Diffraction (TOFD) is a rece...

Non-destructive testing by ultrasounds has been widely used to characterize cementitious materials. Ultrasonic techniques allow estimating mechanical properties of these materials by measuring both velocity and attenuation of the propagating ultrasonic pulse. In this study, both content and size of aggregates in mortar specimens are estimated by taking into account an optimization formulation w...

Nondestructive evaluation of materials, the science of identifying the physical and mechanical properties of materials without altering their end-use capabilities, is valuable in defining relationships between properties and performance of materials. Nondestructive evaluation techniques using these relationships have current industrial applications. They are used for machine stress rating of lu...

Ultrasonic testing data is usually visualised in form of Cand D-images. For simple inspection tasks of flat samples, these representation methods are an effective means for identifying and evaluating defects. However, for complex inspection tasks, e.g. testing of large curved composite structures, it is often difficult to relate the findings to the tested structure. Therefore it is important to...

In ultrasonic non-destructive testing of materials with a coarse-grained structure the scattering from the grains causes backscattering noise, which masks flaw echoes in the measured signal. Several filtering methods have been proposed for improving the signal-to-noise ratio. In this paper we present a comparative study of methods based on the wavelet transform. Experiments with stationary, dis...