Characteristics of a high power ultrasonic array transmitter in air
A high-power ultrasonic array transmitter with 144 transmitting elements for 3D measurements in air has been developed. The sound pressure level of 126 dB was obtained at a distance of 5 m in the air with an ultrasonic frequency of 40 kHz. This value is approximately 32 dB higher than that obtained using a single transmitting element. The characteristics of the array transmitter were studied and compared with simulation results. The experimental results were in good agreement with the simulation results.
Characteristics of an ultrasonic phased array transmitter in medium range
HIGHLIGHTSA portable ultrasonic phased array transmitter with 12 × 12 transmitting elements.High sound pressure level in medium range for efficient presence detection.Reliable privacy maintained security and health monitoring applications.Useful for adverse atmospheric conditions such as darkness and smoke etc.Novel tool for dynamic and accurate health care. ABSTRACT An ultrasonic phased array transmitter (PAT) consisting of 12 × 12 elements was designed and fabricated to evaluate its experimental characteristic performance in the medium range of 2 m–10 m for its directivity, pulse width affect and sound pressure level (SPL) measurements as a function of distance from its center in the open air. The SPL was measured at 2 m, 5 m, and 10 m distances as 135 dB, 126 dB and 68 dB, respectively. The experimentally measured directivity patterns were found in good agreement with the theoretical results obtained by using MATLAB simulations. The SPL showed negligible change as a function of the ultrasonic pulse widths such as 0.5 ms, 1 ms and 2 ms. The SPL and directivity of the PAT at 2 m distance were measured for ultrasonic pulse width of 0.1 ms only while as at 10 m distance these were measured for the ultrasonic pulse widths of 0.5 ms, 1 ms and 2 ms. The present investigations on the PAT characteristics are expected to be useful for its industrial, scientific and biomedical applications, e.g., robotics for 3D range imaging with improved and efficient object presence sensing as well as nondestructive health monitoring.
Finite Difference Modeling on the Temperature Field of Substrate in Friction Surfacing
Friction surfacing is an advanced process of great potential, especially in the field of repair and reclamation of worn and damaged components. As a kind of thermal processing technology, the temperature profile and changes of the substrate in friction surfacing are important factors to get coatings of high quality. In this paper, the temperature field of the substrate during the process is simulated by finite difference method. The results are consistent with experiments, reappearing the temperature change of the substrate during friction surfacing, allowing further study on figuration and quality of coatings.