Acoustic waves are the form of propagation of the mechanical
vibration state (or energy) of an object. Ultrasound refers to the
vibration frequency is greater than 20000Hz above, its frequency of
vibration per second (frequency) is very high, beyond the general
limit of human hearing (20000Hz), people will call this inaudible
sound waves called ultrasound. Because of its high frequency, it
has many characteristics: First, it has a large power, and its
energy is much larger than the general sound wave, so it can be
used for cutting, welding, drilling and so on. Furthermore, because
of its high frequency, short wavelength, and poor diffraction, it
has good directionality, and ultrasound is commonly used in
industrial and medical applications for ultrasonic detection. [1]
Ultrasound and audible sound are essentially the same. Their common
point is a kind of mechanical vibration mode. It usually propagates
in the elastic medium in the form of longitudinal waves. It is a
form of energy transmission. Its difference is Ultrasonic frequency
is high, the wavelength is short, and it has good beam
directionality and directivity in a straight line within a certain
distance, 1 megahertz=10^6Hz, ie each
Ultrasonic welding machine
Ultrasonic welding machine
The second vibration is 1 million times, and the frequency of the
audible wave is between 16-20000HZ).
APPLICATION ANSWER
1.The frequency limit of apiezoceramic sheet and some properties?
Usually the frequency limits of applications are ascertained
through the resonances involved with the transducer design and its
size and shape. For a piezoceramic sheet, there is no limit for
inherent frequency. A sheet of PSI-5A material which is 2.85″
square, .0075″ thick has planar dilatation mode of about 14 KHz and
of 13 MHz of thickness mode vibration in the neighborhood. Limiting
factors can arise such as the resistive heating of electrodes when
considerable current is gathered at large surface area parts during
ultrasonic frequencies.
2.Is there any truth to piezo transducers being used as static and
dynamic force sensors?
Due to charge leakage the Piezo transducers cannot be used for
static force measurements. For transient force measurements they
can be applied successfully for only0.1 second.
3.The expected life of piezoelectric material?
There are no tests yet that can determine the “fatigue life”. Our
facility has had an operational piezo fan since 1982. Such
calculations must involve voltages and mounting.
4.How does temperature effectpiezoceramic transducers?
The pyroelectric properties of piezoceramic are responsible for the
appearance of voltage through the any piezo transducer electrodes
due to temperature changes. Almost each and every property of
piezoceramics is affected by temperature. There exists no general
manner regarding it. In accordance to your experiment and
calculations, the dependence must be looked upon in that context.
