High stability piezoelectric force sensor.

Many dynamic stress sensors use piezoelectric ceramics. They are active sensors, generally broadband for low frequency applications. It is usual that a high static stress is superimposed to the dynamic stress to be measured (hydrophones, force ring sensors, etc.). In this case, the active part has to commit with two important conditions: 1 degrees) the use of a material presenting the most linear behavior in the working force range. 2 degrees) the use of a geometry bringing a stress repartition favoring a linear behavior of the material. The original proposed solution is a sensor made with two parts mechanically and electrically serie connected. Each part with a different geometry has a specific variation with the applied force. It is shown that for an adequate configuration, both variations compensate allowing a great stability of the assembly.