The piezoshaker excitation systems are designed for vibration measurement and non destructive testing and consist of a piezoshaker, an amplifier and a function generator. Optionally, the waves of the piezoshaker, transmitted to the test object, can be monitored by isi-sys Shearography / ESPI systems. Our Shearography / ESPI systems enable to monitor full field vibration such as e. g. the natural object vibrations. The video on the right shows the lamb waves, generated by the piezoshaker, that is attached at the bottom of the specimen. The waves travel across the object surface and excite the five local subsurface defects on the top. The local defects vibrate differently, depending on their local mechanical properties (stiffness). Only very little power of the piezoshaker is required, when the excitation frequency is close to the local defect resonance frequency. This principle is used in non-destructive testing for example, especially to locate delaminations in sandwich structures. Here, usually the piezoshakers of the PS-X-03 series with vacuum adapter are used.
PS-X-03 Series with Suction Cup adapter
The PS-X-03-Series is designed for non destructive testing purpose in combination with ESPI/Shearography. It is fixed on the object surface by vacuum via a suction cup. The pressing force is adjustable by the vacuum level. Different actuator types are available for different frequency range and forces in combination with different counterweight mass.
PS-L-02-Series with mounting table and forced cooling
The PS-L-02 Series is designed for vibrating of small objects such as electronic devices at high frequencies. The adapter table is exchangeable and can be customized with threads for object mounting (M4). Mounting of load cell for force measurement is optional. Mass of gravity of the object should be near center. For continuous operation at high loads and frequencies forced air cooling is required. A DC centrifugal fan is included, which can be connected to the amplifier for powering. It is available with different characteristics (frequency range, amplitudes and forces).
PS-M-LC-Series with screw mount and load cell adapter
The PS-M-LC-Series is designed for screwing or gluing on the object surface and can be combined with load cells. The piezoshaker is available with actuator types for different force and frequency ranges in combination with variation of the housing diameters defending the counterweight mass of the shaker body. A suitable and common load cell is for example the PCB model No. 201B02 (Force Sensor ICP® quartz force ring), which max. Frequency is 90kHz.
The amplifier HVDA-0-180 is especially design for isi-sys Piezoshakers and mobile application, where high power at low weight and compact size is a big advantage for mobility and flexible handling. Modular or customized versions for Shearography units including function generator and vacuum pump. High frequencies up to 100kHz and more as well as large forces and acceleration have been generated in combination with the different isi-sys Piezoshaker modules.
Excitation power, force and acceleration of a piezoshaker system are functions of the frequency, its amplitude and thus also depend on the amplifier output, characterized by its transfer function. You can request the transfer function of the amplifier from isi-sys. The frequency range for application of the piezoshaker is limited depending on its electrical capacity. Adjustment of the excitation power is usually possible via the amplitude and frequency generated by the function generator and can be monitored via the voltage and current monitor-outputs.
Function generator / DAQ unit
Different function generators are supported by the Software isi-Studio. It offers to run the requires features for non destructive testing such as automatic frequency sweeping. The standard function generator / DAQ unit also offers to measure current and voltage output of the amplifier. This permits to monitor the power applied to the surface.
The Piezoshaker can be attached by vacuum to the object surface. When pressurized air is not available, isi-sys offers small vacuum pump units. Two independent vacuum sources are recommended when also a tripod with suction cups is used. The vacuum level is adjustable via pump speed, which is recommended to prevent damage to the object surface by vacuum forces.