TOPIC 3 ACOUSTIC SONIC SUBSONIC ACOUSTICS 22 03

TOPIC – 3 ACOUSTIC, SONIC, SUB-SONIC

ACOUSTICS 22: 03 § The word acoustics derived from Ancient Greek Word means “Able to be heard". § Acoustics is the branch of physics. § Associated with “Study of sound”. § It is the Science concerned with the – Production, Control, Transmission, Reception & Effects of sound.

ACOUSTICS 22: 03 § It describes the phenomenon of Mechanical vibration and their propagation in Solids, Liquids and Gaseous materials. § In Vacuum – No Sound.

SONIC & SOUND 22: 03 § Sonic is related to or using sound. § Sound Waves are Mechanical Waves § Other Waves can be Electro Magnetic Waves § Sound waves are categorized by their frequencies as. . • Subsonic • SONIC • Ultrasonic

CLASSIFICATION OF SOUND WAVES § SUB-SONIC - In-audible to human ear - frequency below 20 hz § SONIC - Audible to human ear - frequency 20 -20000 hz § ULTRASONICS - Inaudible to human ear - frequency above hearing range i. e. above 20000 hz 22: 03

APPLICATION OF UTRASONIC WAVE 22: 03 § Industrial - Ultrasonic welding, Ultrasonic drilling, Ultrasonic cleaning, Ultrasonic testing etc. § Material Characterisation – NDT of material, Hardness testing, Phase change, Stress measurement etc. § Navigation (SONAR) - Sound Navigation And Ranging, Locating ships, submarines & mines, Ocean depth, Condition of material. § Medical diagnostics - To detect & locate fissure, tumors & other ailing organs of human body, Cleaning & detection of cracks, cleaning of teeth, Measure of ‘back-fat ‘ on livestock, Lithotripsy - in kidney stones, Liposuction & cataract treatment.

ULTRASONIC SPECTRUM APPLICATION • ULTRASONIC DRILLING FREQUENCY - 25 khz • CLEANING &UNDER WATER SIGNALING - 40 khz • MATERIAL WITH LARGE GRAIN - 500 khz • MATERIAL WITH FINE GRAIN - 2 -4 mhz • FINE HOMOGENEOUS MATERIAL - 5 mhz • Max. FREQUENCY FOR TESTING - 15 mhz 22: 03