Actuators

  • Large-scale, high-performance dynamic and static actuators, providing the ability to conduct dynamic, pseudo-dynamic, hybrid pseudo-dynamic testing.
  • The actuators and associated control systems will allow for the development of new testing methodologies, including the effective force control testing method, in which large structures could be directly subjected to dynamic excitations without the need for shake tables.
  • A large reaction wall, built next to the shake tables and equipped with dynamic actuators, will allow for the application of computer-predicted external forces on shake table-mounted substructures, thus simulating the reaction of the entire structure (Real-Time Dynamic Hybrid Testing, or RTDHT).
  • Equipment required to operate the actuators, including a high-capacity, high-performance hydraulic supply and distribution system (up to 1600 gpm), and numerous digital control systems.
  • Networked tele-experimentation capabilities using modular and expandable teleobservation and teleoperation equipment, tied to the testing systems using discrete and global sensors, including high-resolution digital video and imaging capabilities.

Real Time Structural System Specifications:

    A. Dynamic Actuator Assemblies (Quantity 3 sets)
    • 244.51S 100 Ton Dynamic Actuator Assembly
      • Linear Hydraulic Actuator
      • Dynamically Rated for high performance testing.
      • 100 tons static rated, 90 tons dynamic rated.
      • Double acting (hydraulic pressure on both sides of the equal area piston)
      • LVDT type full stroke coaxially mounted displacement transducer
      • Polymeric bearings for low friction and high side load capability
      • Double amplitude displacement, 40 inches, +/- 20 inches (Note that these long stroke actuators will have low natural frequencies)
      • Rubber rest pads to protect actuator and floor during storage
      • Lifting shackles
    • Swivel Head Assembly, MTS Model 249.51
      • Rated force capacity, ± 100 tons
      • Adjustable bearing clearance to minimize backlash
      • Tilt angle ±8 °
      • Swivel angle +90 °, -30°
    • Swivel Base Assembly, MTS Model 249.51
      • Rated force capacity, ± 100 tons
      • Adjustable bearing clearance to minimize backlash
      • Tilt angle ±8°
      • Swivel angle +90 °, -30 °
    • Hydraulic Servovalve Assembly
      • There is also MTS 256.80S three stage servovalve for this application. This valve is rated in excess of 3000 LPM and will provide the ability to run demanding earthquake records for real time hybrid applications.
        A load of approximately 150 kips (70 tons) can be achieved at 1 meter/second velocity condition with this valve assembly.
        Additionally, a custom port shut off valve assembly and a second low flow servovalve manifold with a conventional MTS 252.25 (57 LPM) servovalve and port shut off. This will allow either high flow or low flow operation with the actuators. The port shut off valves requires a manual operation and the operator must also switch the valve electronic cables to move from one configuration to the other.
    • Load Cell, MTS Model 661.31E-01
      • Rated at ± 100 tons force capacity
      • Single bridge
      • 150% static load capacity
      • 1 x 109 cycles fatigue at ±75% of rated load
      • Combined accuracy of load cell and transducer conditioner of 0.5% of range for loads between 0% and 100% of calibrated range.

    B. Static Actuator Assemblies (Quantity 2 sets)
    • 243.90T Linear Hydraulic Actuator
      • Recommended for static applications.
      • Standard Rated force capacity: 446 kip Tension / 600 kip Compression, but for this application, MTS will include a load limiting valve on the compression side limiting it to 446 kips tension/446 kips compression allowing for matched size pivot head and base.
      • Single ended (piston rod extends from front end of the unequal area piston)
      • Double acting (hydraulic pressure on both sides of the unequal area piston)
      • Full stroke coaxially mounted Temposonics II displacement transducer
      • High quality, non-metallic bearings provide long life and resist bearing-to-rod galling failures
      • Rubber rest pads to protect actuator and floor during storage
      • Lifting shackles
      • Double amplitude displacement: 40 inches, (single amplitude: ± 20 inches)
      • Compression Relief Valve - Factory set pressure relief valve limits compressive force to 446 kip to allow MTS 243.80 pivot head and base assemblies rated at +/- 446 kips to be used.
      • Allows selection of lower capacity swivels and load cell when maximum compression of actuator is not required
      • Located on the servovalve manifold
    • 243.80 Pivot Head Assembly
      • Rated force capacity: ± 446 kip
      • Swivel angle: + 90°, - 80°
      • Not for use on cyclic, reversing load applications.
    • 243.80 Pivot Base Assembly
      • Rated force capacity: ± 446 kip
      • Swivel angle: + 90°, - 80°
      • Not for use on cyclic, reversing load applications.
    • Servovalve Manifold Assembly for 252.25 Servovalve
      • Servovalve manifold with dual servovalve mounting capability (one valve included). Cover plate over unused valve ports.
      • Two stage, four way operation
      • Four port valve.
      • Requires two stage valve driver
      • One MTS 252.25 Servovalve, 15 gpm included.
    • 660.23 Differential Pressure Cell
      • Used for load control or readout in the absence of a load cell.
      • Includes protection manifold to eliminate damage due to pressure spikes.

    C. Hydraulic Power Supply Subsystem
    • MTS Model 506.92 HPS (quantity =4)
      • Rated at 185 gpm (700 lpm) at 3,000 psi (207 bar) each.
    • High Flow Hydraulic Distribution Manifolds (qty 4 locations)
      • Four high flow hydraulic distribution manifolds that will each allow a high flow actuator running 800 GPM valves to be connected through itís 800 gpm Hydraulic service Manifold. These manifolds will be located on the strong floor area. These manifolds will each have four, four bolt flange ports with independent manual shut off valves to allow the four 2 inch hose sets to be attached simultaneously for the 800 GPM servovalve performance actuators.
    • Hydraulic Distribution Outlet Manifolds (qty 3 total)
      • Three Hydraulic distribution Outlet stations with 2 sets of ball and check valves will be provided near the south end of the strong floor feeding from the 50 mm diameter piping system.
    • Custom 800 gpm Hydraulic Service manifolds (qty 3 total)
      • Three, High flow HSMís, one for each high flow actuator will be provided with 40 gallons each of pressure and return accumulation. Each manifold will have pilot pressure on, low flow low pressure, and a high flow high pressure electronically switchable states and can control one high flow actuator configured with an 800 GPM valve. One subtle feature of these custom manifolds is that the pressure and return line accumulators are always active when connected to the distribution system providing additional accumulation throughout the distribution system.
    • MTS 293.12 Low Flow Hydraulic Service Manifold (qty 2)
      • Two HSMís with single station control will be provided. Each HSM allows turning off pressure to an actuator without shutting down the HPU. These would be used for the MTS 243 static actuators.
      • Hydraulic ramp (low to high and high to low) reduces shock to specimen, provides pressure regulation, reduces the chance of specimen damage, and increases the life of the hydraulic components.
      • Local accumulators protect the hydraulic lines from pressure spikes and reduce flow fluctuations resulting from changing system demands. (1 gallon pressure and 1 quart return line accumulators)
      • 10 micron main filtration
    • Servovalve controllers for low flow services MTS 407 (5 sets)
    • Miscellaneous Piping, Manifolds, fitting, etc. to integrate the structural components to the main hardline system.
      • The hydraulic distribution system will be designed to meet an oil filtration quality of ISO 13/10. This level of cleanliness is critical for high fidelity servovalve systems.

   
   
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Cable-stayed bridge segment with RTDHT using two shake tables, reaction walls, and large-scale high performance actuators.
   
   
   
   
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Real-time hybrid seismic testing system (Substructure dynamic testing)
   
   
   
   
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Detailed Planview of the lab
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Detailed Cross section of the lab
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SEESL - Structural Engineering and Earthquake Simulation Laboratory
212 Ketter Hall, Buffalo, NY 14260, USA
phone. +1(716)645-3019       fax. +1(716)645-3733