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Piezoelectric balance presented by Pierre Curie to Lord Kelvin, Hunterian Museum, Glasgow. Piezoelectricity [note 1] is the electric charge that accumulates in certain solid materials—such as crystals, certain ceramics, and biological matter such as bone, DNA, and various proteins—in response to applied mechanical stress.
The first constitutive equation (constitutive law) was developed by Robert Hooke and is known as Hooke's law.It deals with the case of linear elastic materials.Following this discovery, this type of equation, often called a "stress-strain relation" in this example, but also called a "constitutive assumption" or an "equation of state" was commonly used.
The piezoelectric coefficient or piezoelectric modulus, usually written d 33, quantifies the volume change when a piezoelectric material is subject to an electric ...
This is known as the constitutive equation for electric fields. Here ε 0 is the electric permittivity of empty space. In this equation, P is the (negative of the) field induced in the material when the "fixed" charges, the dipoles, shift in response to the total underlying field E , whereas D is the field due to the remaining charges, known as ...
Maxwell's equations are partial differential equations that relate the electric and magnetic fields to each other and to the electric charges and currents. Often, the charges and currents are themselves dependent on the electric and magnetic fields via the Lorentz force equation and the constitutive relations.
Piezoelectric polymers (PVDF, 240 mV-m/N) possess higher piezoelectric stress constants (g 33), an important parameter in sensors, than ceramics (PZT, 11 mV-m/N), which show that they can be better sensors than ceramics. Moreover, piezoelectric polymeric sensors and actuators, due to their processing flexibility, can be readily manufactured ...
The cross-section of a piezoelectric accelerometer. The word piezoelectric finds its roots in the Greek word piezein, which means to squeeze or press. When a physical force is exerted on the accelerometer, the seismic mass loads the piezoelectric element according to Newton's second law of motion (=). The force exerted on the piezoelectric ...
The electromechanical coupling coefficient is a numerical measure of the conversion efficiency between electrical and acoustic energy in piezoelectric materials. Qualitatively the electromechanical coupling coefficient, k, can be described as: