A method to classify piezoelectric crystals
Changjiu Dang · The Journal of the Acoustical Society of America · 2005
The properties of piezoelectric crystals used as the active elements in many ultrasonic transducers vary among the suppliers even if the crystals are claimed to be in the same category (say Navy I). A method of classifying the piezoelectric crystals is introduced. With this method, one can judge how similar to each other two types of crystals are by taking the crystal parameters as inputs. The parameters of a crystal include its density, velocity, mechanical Q, dissipation, frequency constants, piezoelectric constants, elastic constants, etc. They are transformed into the values around 1 to weaken the dominance of large parameter values. The transformed data form two attribute lists whose cross-correlation indicates their similarity. If two crystals are similar, their normalized cross-correlation coefficient is close to 1. Otherwise, it is close to 0. Based on this method, the available piezoelectric crystals can be further classified into different groups.