Impedance Head is unaffected by mass loading.
Press Release Summary:
Model 8770A Impedance Head yields simultaneous dynamic acceleration and force data from identical acquisition points. Types 8770A5 and 8770A50 provide acceleration and force ranges to +5g and +51bf or Â±50g and +501bf respectively. Outputs are phase matched to within 2Â° with acceleration and force sensitivities unaffected by mounting or torque. Quartz and ceramic piezoelectric sensing elements yield acceleration frequency responses of 1 Hz to 4kHz.
Original Press Release:
Impedance Head Simultaneously Measures Dynamic Acceleration and Force
Kistler's unique sensing element construction optimizes the performance capability of the 8770A Impedance Head such that it yields simultaneous dynamic acceleration and force data from exactly the same location on a test structure. Available in two versions, the types 8770A5 and 8770A50 provide acceleration and force ranges to +5g and +51bf or ±50g and +501bf respectively. Both outputs are phase matched to within two degrees with acceleration and force sensitivities unaffected by mounting torque or mass loading.
The novel blend of quartz and ceramic piezoelectric sensing elements, optimizes the performance of the of the 8770 yielding an acceleration frequency response of 1 Hz to 4kHz which is unaffected by mass loading. The high stiffness of the shear sensitive elements ensures high force transfer to the test structure. The integrated Piezotron electronics provide convenient low impedance, voltage mode outputs. The impedance head has a hermetically sealed titanium case and conforms to C E directives. The sensor can be powered a wide variety of Kistler Coupler/Signal Conditioners or from any industry standard IEPE power source.
The most common use for the impedance head is in modal analysis and the acquisition of driving point data. Typically the sensor is installed on a test article and connected by a threaded stinger to a vibration shaker.