How do shear accelerometers work ?

Shear mode accelerometer (vibration sensor) designs feature sensing crystals attached between a center post and a seismic mass. A compression ring or stud applies a pre-load force to the element assembly to insure a rigid structure and linear behavior. 

Under acceleration, the mass causes a shear stress to be applied to the sensing crystals. This stress results in a proportional electrical output by the piezoelectric material. The output is collected by electrodes and transmitted by lightweight lead wires to either the built-in signal conditioning circuitry of ICP sensors, or directly to the electrical connector for charge mode types.

By having the sensing crystals isolated from the base and housing. shear mode accelerometers excel in rejecting thermal transient and base-bending effects. Also, the shear geometry lends itself to small size, which promotes high frequency response while minimizing mass loading effects on the test structure.

With this combination of ideal characteristics, shear mode accelerometers offer optimum performance.