HYDRA Multi-axis shaker
GENERAL DESCRIPTION
HYDRA is a 6 degree of freedom hydraulic vibration test stand developed for mechanical qualification of Space hardware but also used for qualification of equipment from other industrial sectors, such as aviation, railway, automotive, marine, energy, civil, communication as well as for R&D purposes.
The 5.5m octagon shaped test table of 21 ton is excited by 8 powerful hydraulic actuators of which four act in vertical direction and the other four in horizontal direction symmetrically around the circumference. A state-of-the-art hydraulic power unit supplies the actuators in a closed loop with the required oil flow at a pressure of 300 bar. The motion control of the individual actuators is accomplished by high performance 3-stage servo-valves which are controlled by a sophisticated 6 degree of freedom vibration control system.
HYDRA operates in a frequency regime of 0.1Hz - 100Hz and an acceleration range of 0.01 – 5g. A full-blown structural analytical model of the facility is available for coupling with the specimen model to predict test item behaviour.
Test modes
The vibration input is generated by a state-of-the-art vibration controller with up to 80 control and measurement channels, of which 48 usable for test article response limiting.
A variety of types of excitation is available:
- Sine testing, e.g. sine sweep, tracked sine dwell
- Random testing
- Transient testing, e.g. earth quake simulation, classic shock, arbitrary waveform replication/FRS
Test article responses are measured by a dedicated mechanical data handling system, offering up to 800 channels.
Mechanical Interface
The aluminium alloy head expander connected to the 8 actuators creates a 5.5x5.5m interface for payload installation.
The test table interface plate is equipped with M20 inserts on a regular 320x320mm grid pattern and 24x M24 inserts equally spaced on a concentric hole pattern of 2740mm PCD.
The test table has a flatness of less than 0.1mm/m to facilitate proper load transfer to the payload.