2.1 Hydraulic Actuators

The laboratories feature numerous actuators suitable for a variety of different testing procedures. A detailed listing of the different actuators is presented in table 1 and the detailed descriptions follow the table.

Figure 1: MTS 243.90T Actuators (click to enlarge)

Figure 2: MTS 244.51S Actuator (click to enlarge)

Table 1 : Available Hydraulic Actuators and Jacks
 

Actuator Type/ Serial No.	Quantity	Load Capacity kips [kN]	Area in^2 [cm^2]	Stroke in. [mm]	Servovalve Type	Servo Controller	Servovalve gpm [lpm]	Peak Velocity* in./sec [mm/sec]	Equipment Designation ***
MTS Servo-controlled Static Rated Single-ended, double acting 243.90T	2	440[1962]	146.7 [946.4]	40	MTS 252.25	MTS 406, 458, 407, FlexTest	15[56.78]	0.393[9.982]	NEES
Miller Servo-controlled Static Rated/ DH53/173393 & DH/250930	2	250 [1112.06]	83.3 [537.4]	8 [203.20]	252.25	MTS 406, 458, 407, FlexTest	15 [56.78]	0.65 [16.5]	Non-NEES
MTS Servo-controlled Dynamic Double acting 244.51S	3	220[978.61]	73.3 [472.9]	40	MTS 256.80S ****	MTS 469D, FlexTest (?)	800[3000]	42[1066.8]	NEES
					MTS 252.25	MTS 406, 458, 407, FlexTest	15[56.78]	0.75 (19.1)
MTS Servo-controlled Dynamic Rated Double Rod/ 244.51/149	1	220 [978.61]	73.3 [472.9]	10 [254.0]	252.25	MTS 406, 458, 407, FlexTest	15 [56.78]	0.75 [19.1]	Non-NEES
					256.25	MTS 406, 458, 407, FlexTest	250 [946.35]	12.5 [317.5]
MTS Servo-controlled Dynamic Rated Double Rod/ 244.41/160	1	110 [489.30]	36.7 [236.8]	10 [254.0]	252.25	MTS 406, 458, 407, FlexTest	15 [56.78]	1.5 [38.1]	Non-NEES
					256.25	MTS 406, 458, 407, FlexTest	250 [946.35]	25 [635.0]
Parker Servo-controlled Static Rated Single-ended/ 1C2HLT18	4	70 [311.38]	23.3 [150.3]	4 [101.60]	252.25	MTS 406, 458, 407, FlexTest	15 [56.78]	2.4 [60.96]	Non-NEES
MTS Servo-controlled Dynamic Rated Double Rod/ 244.31/360	1	55 [244.65]	18.3 [118.1]	24 [609.6]	252.25	MTS 406, 458, 407, FlexTest	15 [56.78]	2.95 [74.9]	Non-NEES
MTS Servo-controlled Dynamic Rated Double Rod/ 244.31/393	1	55 [244.65]	18.3 [118.1]	12 [304.8]	256.09	MTS 406, 458, 469, 407, FlexTest	90 [340.69]	17 [431.8]	Non-NEES
MTS Servo-controlled Dynamic Rated Double Rod/ 204.63/503	1	22 [97.86]	7.3 [47.1]	6 [152.4]	252.24	MTS 406, 458, 407, FlexTest	10 [37.85]	5 [127.0]	Non-NEES
MTS Servo-controlled Dynamic Rated Double Rod/ 244.12/222	1	5.5 [24.47]	1.8 [11.61]	6 [152.4]	252.25 x 2	MTS 406, 458, 469, 407, FlexTest	30 [113.56]	50 [1270.0]	Non-NEES
MTS Servo-controlled Dynamic Rated Double Rod/ 244.12/585	1	5.5 [24.47]	1.8 [11.61]	6 [152.4]	252.25	MTS 406, 458, 469, 407, FlexTest	15 [56.78]	27 [685.8]	Non-NEES
MTS Servo-controlled Dynamic Rated Double Rod/ 244.00/308	1	2.2 [9.79]	0.7 [4.516]	4 [101.6]	252.24	MTS 406, 458, 407, FlexTest	10 [37.85]	49 [1244.6]	Non-NEES
Enerpac Hollow Core Jack	1	60 [267]	20 [129]	> 4 [101.6]	NA	NA	None	NA	Non-NEES
Enerpac Solid Core Jack	1	80 [355.86]	26.7 [172.3]	> 4 [101.6]	NA	NA	None	NA	Non-NEES
Enerpac Solid Core Jack	1	50 [222.41]	16.7 [107.7]	> 4 [101.6]	NA	NA	None	NA	Non-NEES

* Velocity assumes no load on actuator
** Same as previously listed actuator with different servovalve
*** Fees will not be applied to scheduled NEES projects. Fees wil be charged for extra unscheduled time. Disclaimer: The rates are direct costs only and DO NOT include a 57% Department fee for administration and university fees. This overhead has to be added in estimates.
**** MTS 256.80S servovalve be controlled with MTS 469D controller ONLY

• MTS Systems Corporation servo-controlled static rated actuator (x2) with a load capacity of 440 kips (1962 kN) and an available stroke of 40 in. The actuator's servovalve has a flow rate of 15 gpm (56.78 lpm), and the actuator has a maximum velocity of 0.393 in./sec (9.982 mm/sec) with that particular valve.

• Miller servo-controlled static rated actuators (x2) with a load capacity of 250 kips (1112.06 kN) and an available stroke of 8 in. (203.2 mm). The actuator's servovalve has a flow rate of 15 gpm (56.78 lpm), and the actuator has a maximum velocity of 0.65 in./sec (16.5 mm/sec) with that particular valve. Force is measured using manufacture supplied load cells and displacement is measured using internally mounted LVDTs.

• MTS Systems Corporation servo-controlled dynamic rated actuator (x3) with a load capacity of 220 kips (978.61 kN) and an available stroke of 40 in.. The actuator's servovalve has a flow rate of 15 gpm (56.78 lpm), and the actuator has a maximum velocity of 0.75 in./sec (19.1 mm/sec) with that particular valve. This particular actuator is equipped with an alternate servovalve for high speed testing which has a flow rate of 800 gpm (3000 lpm), and the actuator has a maximum velocity of 42in./sec (1066.8 mm/sec). Force is measured using a manufacture supplied load cell and displacement is measured using internally mounted LVDTs.

• MTS Systems Corporation servo-controlled dynamic rated actuator (x1) with a load capacity of 220 kips (978.61 kN) and an available stroke of 10 in. (254.0 mm). The actuator's servovalve has a flow rate of 15 gpm (56.78 lpm), and the actuator has a maximum velocity of 0.75 in./sec (19.1 mm/sec) with that particular valve. This particular actuator is equipped with an alternate servovalve for high speed testing which has a flow rate of 250 gpm (946.35 lpm), and the actuator has a maximum velocity of 12.5 in./sec (317.5 mm/sec). Force is measured using a manufacture supplied load cell and displacement is measured using internally mounted LVDTs.

• MTS Systems Corporation servo-controlled dynamic rated actuator (x1) with a load capacity of 110 kips (489.30 kN) and an available stroke of 10 in. (254.0 mm). The actuator's servovalve has a flow rate of 15 gpm (56.78 lpm), and the actuator has a maximum velocity of 1.5 in./sec (38.1 mm/sec) with that particular valve. This particular actuator is equipped with an alternate servovalve for high speed testing which has a flow rate of 250 gpm (946.35 lpm), and the actuator has a maximum velocity of 25 in./sec (635.0 mm/sec). Force is measured using a manufacture supplied load cell and displacements is determined using internally mounted LVDTs.

• Parker servo-controlled static rated actuators (x4) with a load capacity of 70 kips (311.38 kN) and an available stroke of 4 in. (101.60 mm). The actuator's servovalves have flow rates of 15 gpm (56.78 lpm), and the actuators have a maximum velocity of 2.4 in./sec (60.96 mm/sec) with that particular valve. Due to the fact that the actuators are single-ended, they are primarily used for vertical load application. Force is measured using in-house custom built load cells and displacement is measured using external displacement transducers.

• MTS Systems Corporation servo-controlled dynamic rated actuator (x1) with a load capacity of 55 kips (244.65 kN) and an available stroke of 12 in. (304.8 mm). The actuator's servovalve has a flow rate of 90 gpm (340.69 lpm), and the actuator has a maximum velocity of 17 in./sec (431.8 mm/sec) with that particular valve. Force is measured using a manufacture supplied load cell and displacement is measured using internally mounted LVDTs.

• MTS Systems Corporation servo-controlled dynamic rated actuator (x1) with a load capacity of 55 kips (244.65 kN) and an available stroke of 24 in. (609.6 mm). The actuator's servovalve has a flow rate of 15 gpm (56.78 lpm), and the actuator has a maximum velocity of 2.95 in./sec (74.9 mm/sec) with that particular valve. Force is measured using a manufacture supplied load cell and displacement is measured using internally mounted LVDTs.

• MTS Systems Corporation servo-controlled dynamic rated actuator (x1) with a load capacity of 22 kips (97.86 kN) and an available stroke of 6 in. (152.4 mm). The actuator's servovalve has a flow rate of 10 gpm (37.85 lpm), and the actuator has a maximum velocity of 5 in./sec (127.0 mm/sec) with that particular valve. Force is measured using an in-house custom built load cell and displacement is measured using internally mounted LVDTs

• MTS Systems Corporation servo-controlled dynamic rated actuators (x2) with load capacities of 5.5 kips (24.47 kN) and an available stroke of 6 in. (152.4 mm). One actuators servovalve has a flow rate of 30 gpm (113.56 lpm), and the actuator has a maximum velocity of 50 in./sec (1270.0 mm/sec) with that particular valve. The other actuators servovalve has a flow rate of 15 gpm (56.78 lpm), and the actuator has a maximum velocity of 27 in./sec (685.8 mm/sec) with that particular valve. Force is measured using in-house custom built load cells and displacement is measured using internally mounted LVDTs.

• MTS Systems Corporation servo-controlled dynamic rated actuator (x1) with a load capacity of 2.2 kips (9.79 kN) and an available stroke of 4 in. (101.6 mm). The actuators servovalve has a flow rate of 10 gpm (37.85 lpm), and the actuator has a maximum velocity of 49 in./sec (1244.6 mm/sec) with that particular valve. Force is measured using a manufacture supplied load cell and displacement is measured using internally mounted LVDT's.

In addition to the hydraulic actuators, the laboratories are equipped with a number of hydraulic jacks. Table 1 is a summary of all the available hydraulic actuators and jacks in the Structural and Earthquake Engineering Laboratory.

2.1.1 Analog Controllers

The lab maintains a variety of analog servo-controllers, which are used to provide position, strain or force control to the hydraulic actuators and testing machines. These controllers have been acquired over a period of twenty five years, and are represented by three distinct lines, all manufactured by MTS Systems Corp. A detailed listing of the controlers is presented in table 2 and the detailed descriptions follow the table.

Figure 3: MTS FlexTest (click to enlarge)

Table 2 : Available Servo Controllers
 

Servo Controller Manufacturer	Quantity (# Channels Controlled)	Control Modes	Servovalve Type(s) Controlled	Equipment Designation ****
MTS 406	8	Force / Displacement	MTS 252.24, 252.25	Non-NEES
MTS 406	1	Force / Displacement	MTS 256.09	Non-NEES
MTS 433*	1	Force/ Strain/ Displacement	MTS 252.24, 252.25	Non-NEES
MTS 458**	1(2)	Force/ Strain/Displacement	MTS 252.24, 252.25	Non-NEES
MTS 458	1(2)	Force/ Strain/Displacement	MTS 252.24, 252.25 256.09, 256.25	Non-NEES
MTS 469***	1(5)	Acceleration/ Velocity/ Displacement	MTS 256.09, 256.18	Non-NEES
MTS 469D	1(5)	Acceleration/ Velocity/ Displacement	256.80S	NEES
MTS 407	5	Force / Displacement / Stress	MTS 252.24, 252.25 256.09, 256.25	NEES
MTS FlexTest	1(6)	Acceleration/ Force / Displacement	MTS 252.24, 252.25 256.09, 256.25	NEES

* Dedicated controller for MTS 150 kip Tension Machine
** Dedicated controller for MTS Axial / Torsion Testing Machine
*** Dedicated controllers for MTS/SUNY Seismic Simulator
**** Fees will not be applied to scheduled NEES projects. Fees wil be charged for extra unscheduled time. Servo controller substitution is availible for one time fee of $1200. Disclaimer: The rates are direct costs only and DO NOT include a 57% Department fee for administration and university fees. This overhead has to be added in estimates.

• MTS 433 Servo-Controllers
  These controllers consist of rack mounted card cages (one cage for each controlled channel). Each cage contains modular circuit cards for program input to the actuator, command vs. feedback comparison, load cell conditioning, strain gage bridge completion and conditioning, LVDT conditioning, and program error and limit detection. Due to the size and relative immobility of these controllers, they are dedicated to each of the two MTS Hydraulic Testing Machines (see table 5). While not technically part of the servo controller, a multi-waveform function generator is integral to each of the racks these controllers are mounted in.

A subset of modified MTS 433 controllers (labeled as MTS 469 controllers) is incorporated into the control system for the lab's seismic simulator. This control system provides acceleration, velocity and displacement control for the five active degrees of freedom in which the table is capable of moving. Provisions are also made for cross-coupling control to minimize the error encountered during the testing of tall and/or heavy structures.

• MTS 406 Servo-Controllers
  These controllers consist of portable, table top boxes which contain a main circuit board that provides program input to the actuator, command vs. feedback comparison, error/limit detection and LVDT conditioning. Plug-in cards provide load cell conditioning, third stage valve control, and other custom features as required per application. The portability of these controllers enables them to be moved and reconfigured easily and interfaced with a variety of actuators.

• MTS 458 Servo Controllers
  These are hybrid controllers, consisting of analog and digital technology. They can be configured as either rack mounted or free standing. They consist of a card cage with a fixed hydraulic manifold control module, and interchangeable actuator controllers. These controllers are highly configurable, providing servo control error, limit detection and signal conditioning on each card. Typically, a 458 AC Controller module is configured as the master controller, with an actuator AC LVDT as the feedback device. DC controllers for load and strain feedback (or other AC controllers) are slaved to the master controller, and switching between control modes (displacement, force, strain) is accomplished with a series of push buttons and digital readouts of the controlled variables. Generally speaking, these controllers are dedicated to specific actuators or testing machines, although they can be reconfigured with relative ease.

 2.1.2 Hydraulic Power Supply and Manifolds

The laboratories are supplied with (6) MTS Hydraulic Power Supplies, two MTS 506.81 models and four 506.92 models. Each of 506.81 models consists of (2) discrete hydraulic pumps with individual flow rates of 70 gpm, for a total of 280 gpm. Each of 506.92 models consists of (2) discrete hydraulic pumps with individual flow rates of 90 gpm, for a total of 720 gpm.The pumps can be operated individually or in any combination to achieve the required flow rate. The hydraulic supply is available at several stations throughout the laboratories.



Figure 4: MTS High Flow Hydraulic Distribution Manifold (click to enlarge)



Figure 5: Custom Hydraulic Service manifold (click to enlarge)



Figure 6: MTS 293.12 Low Flow Hydraulic Service Manifold (click to enlarge)

The laboratories are also equipped with the manifolds listed in Table 3 that provide local hydraulic on-off control:

Table 3 - Available Hydraulic Power Supply and Manifolds
 

Device Type	Quantity	Flow Rate (per unit) gpm [lpm]	Equipment Designation
MTS506.81 HPS	2	140* [1245.5]	Non-NEES
MTS Manifold 290 Series	3	50 [189]	Non-NEES
MTS Manifold 290 Series	2	100 [378.54]	Non-NEES
MTS Manifold 290 Series	1	250[946.35]	Non-NEES
MTS Model 506.92 HPS	4	180**[680]	NEES
MTS High Flow Hydraulic Distribution Manifolds	4	800	NEES
Custom Hydraulic Service manifolds	3	800	NEES
MTS 293.12 Low Flow Hydraulic Service Manifold	2	50[189]	NEES

* Flow Rate available in increments of 70 gpm (265 lpm)

** Flow Rate available in increments of 90 gpm (340 lpm)

2.1.3 Integration of Hydraulic Cylinder, Servovalve, Servo-Controller, and Experimental Setup

It is important to understand that the laboratory is not restricted to the specifications of each particular hydraulic actuator. In an actual experiment a hydraulic actuator system is composed of three major components including the hydraulic cylinder, servovalve, and servo-controller. Due to the fact that the majority of the equipment used in the laboratories is manufactured by MTS Systems, the components of each actuator can be interchanged. Different servovalves can be used on the same hydraulic cylinder to produce low and high speed velocities. This in turn may change the rating of the hydraulic actuator from static to dynamic and vice versa. Table 4 provides a complete listing of the available servovalves.

Moreover, different servo-controllers may be used depending on the desired experimental set up. For example, an experiment may entail applying a force to a horizontal beam and at the same time ensuring that the beam is kept horizontal. This would require an initial actuator to apply force to the system as well as a second actuator to ensure that the position of the beam is correct. Different servo-controllers can be used that will allow the system to obtain actual feedback from the two actuators so that any necessary corrections can be made immediately. Refer to Table 2 for a complete list of the available servo controllers.

Table 4 : Available Servovalves

Servovalve Manufacturer	Quantity	Number of Stages	Flow Rate  gpm [lpm]	Equipment Designation **
MTS 252.24	3	2	10 [37.9]	Non-NEES
MTS 252.25	8	2	15 [56.8]	Non-NEES
MTS 256.09	1	3	90 [340.7]	Non-NEES
MTS 256.25	2	3	250 [946]	Non-NEES
MTS 256.09*	4	3	90 [340.7]	Non-NEES
MTS 256.18*	2	3	180 [681.4]	Non-NEES
MTS 256.80S	3	3	800[3000]	NEES

* Permanent Servovalve for seismic simulator
** Fees are for servovalve substitutions only. Fees will not be applied to scheduled NEES projects. Fees wil be charged for extra unscheduled time. Disclaimer: The rates are direct costs only and DO NOT include a 57% Department fee for administration and university fees. This overhead has to be added in estimates.


2.2  Shaking Tables

2.2.1 Six-Degree-of-Freedom Shaking Table (NEES Equipment)

A set of two high-performance, six degrees-of-freedom shake tables, which can be rapidly repositioned from directly adjacent to one another to positions up to 100 feet apart (center-to-center). Together, the tables can host specimens of up to 100 metric tons and as long as 120 feet, and subject them to fully in-phase or totally uncorrelated dynamic excitations.



Figure 7: View of the Six-degree-of-Freedom Shaking Table (A)(click to enlarge)



Figure 8: View of the Six-degree-of-Freedom Shaking Table (B) (click to enlarge)



Figure 9: Top View of the Six-degree-of-Freedom Shaking Table (click to enlarge)

The two shake tables are designed for the following theoretical performance


Table Size:	3. 6 meter x 3.6 meter
Maximum Specimen Mass:	50 ton maximum / 20 ton nominal
Maximum Overturning Moment:	46 ton meter
Maximum Off Center Loading moment:	15 ton meter
Frequency of operation:	.1~50 hertz nominal/100 hertz maximum
Nominal Performance:	X axis Y axis Z axis
Stroke:	±.150 m ±.150 m ±.075 m
Velocity:	1250 mm/sec 1250 mm/sec 500 mm/sec
Acceleration:	±1.15 g ±1.15 g ±1.15 g (w/20ton specimen)

Usage Fees(Fees will not be applied to scheduled NEES projects. Fees wil be charged for extra unscheduled time. Disclaimer: The rates are direct costs only and DO NOT include a 57% Department fee for administration and university fees. This overhead has to be added in estimates):

2.2.1.1 Parking Frame System


A Parking Frame System consisting of a welded steel frame with electric actuators raises the table for repositioning within the length of the trench. The carrier capable of raising the table with the (4) horizontal actuators, (2) actuator buttresses, and (4) vertical actuators is attached. A beam for securing the horizontal actuator buttresses to the table during movement. The carrier rides on polyurethane wheels for ease of positioning and tracks along a center rail embedded in the trench floor being moved with a winch system.

2.2.1.2 Shake Table Hydraulic Actuator Assemblies

1. Longitudinal (X and Y-axis) hydraulic actuator (quantity = 2 each axis)

MTS Model 244.4 Hydraulic Actuator with a dynamic force rating of 21 metric ton and a dynamic stroke of 300 mm (±150 mm). The actuator assembly includes the following:

a. Hollow single piece rod
b. Model 256.25S servovalve rated at 1000 lpm
c. LVDT type stroke transducers
d. Swivel heads and bases
e. Close-coupled pressure and return accumulators
f. Differential pressure cells

2. Vertical (Z-axis) hydraulic actuator (quantity =4)

MTS Model 206.S Hydraulic Actuator with a dynamic force rating of 25 metric ton and a dynamic stroke of 150 mm (±75 mm). The actuator assembly includes the following:

a. Hollow single piece rod
b. Model 256.18s servovalve rated at 650 lpm
c. LVDT type stroke transducers
d. Swivel heads and bases
e. Close-coupled pressure and return accumulators
f. Differential pressure cells
g. Integral static support with 20 ton capacity (total static support capacity is 20 ton x 4 = 80 ton) will all necessary nitrogen supply and control system

Actuator Type	Quantity	Axis	Load Capacity ton	Stroke mm	Servovalve type	Servovalve lpm	Equipment Designation
MTS Servo-controlled Dynamic Rated Double Rod/ MTS 244.4	2	x	21	300	MTS 256.25S	1000	NEES
MTS Servo-controlled Dynamic Rated Double Rod/ MTS 244.4	2	y	21	300	MTS 256.25S	1000	NEES
MTS Servo-controlled Dynamic Rated Double Rod/ MTS 206.S	4	z	25	150	MTS 256.18S	650	NEES


2.2.2 Five-Degree-of-Freedom Large Shaking Table

Located in the Seismic Laboratory, the 12 ft. (3.66 m) by 12 ft. (3.66 m) shaking table has five controlled degrees of freedom (excluding the transverse translational movement), a payload of 110 kips (489.3 kN) and a useful frequency range of 0 to 50 Hz. The table is normally furnished with a reinforced concrete testing platform of 20 ft. (6.1 m) by 12 ft. (3.66 m) plan dimensions that extends the useful testing area beyond the table's dimensions but limits the payload to 85 kips (378.1 kN). The testing platform has holes on a one foot square grid for attaching test specimens.

The longitudinal (horizontal), vertical and roll degrees of freedom are programmable with feedback control to simultaneously control displacement, velocity, and acceleration. The performance envelope of the table is ± 6 in. (15.24 cm) displacement, 30 in./sec (762.0 mm/sec) velocity and 1.15g acceleration at a payload of 44 kips (195.72 kN) in the horizontal direction, and ± 3 in. (7.62 cm) displacement, 20 in./sec (508.0 mm/sec) velocity and 2.30g acceleration in the vertical direction. For a payload of 110 kips (489.3 kN), the maximum acceleration that can be achieved is 0.55g in the horizontal and 1.10g in the vertical directions.

The table is capable of testing a variety of structural systems up to a specimen height of 22 feet above the testing platform.

Figure 4 presents a perspective view of the shaking table and foundation, whereas Figure 5 presents a top view of the testing platform of the shaking table. Figure 6 presents a view of an available testing platform extension of the shake table. Figure 7 presents a top view of a second available testing platform extension of the shake table. Finally, Figure 8 presents a photograph of the shake table with a test specimen installed on it. Appendix A presents additional photographs of specimens on the shake table.



Figure 10: Perspective View of Shaking Table and Foundation (click to enlarge)



Figure 11: Layout of Holes on Shake Table Plate (click to enlarge)



Figure 12 : Layout of Holes on Second Testing Platform Extension of Shake Table (click to enlarge)



Figure 13 : View of Shake Table with Test Specimen (click to enlarge)

2.2.3 Single-Degree-of-Freedom Shaking Table

This 3 ft. (.91 m) by 5 ft. (1.52 m) shaking table has a payload of at least 6 kips (26.7 kN), an available displacement of ± 3 in. (7.62 cm), and can achieve accelerations of 0.8g. The table is driven by a 5.5 kip (24.47 kN) actuator with two 15 gpm (56.78 lpm) servovalves. The specimen height is restricted by uplift conditions since the table rides on slide bearings. It is suitable for use with an available three-story, 6 kip (26.7 kN) steel model structure.



Figure 14 : View of Single-Degree-of-Freedom Shaking Table with Test Specimen (click to enlarge)

2.3 Hydraulic Testing Machines

The laboratory is equipped with (4) hydraulic testing machines. Details and specifications on each are listed below.

Table 5 presents a summary of the hydraulic and universal testing machines available in the laboratories.

Table 5 : Available Hydraulic and Universal Testing Machines
 

Machine Type	Load Capacity Kips [kN]	Stroke Capacity in. [mm]	Controller	Calibration Interval	Equipment Designation **
150 kip Tension Machine*	200, 100, 40, 20 [890, 445, 178, 89]	± 4, 2, 1, .5 [102, 51, 25, 13]	MTS 433	2 Years	Non-NEES
Axial-Torsion MTS Machine*	100, 50, 20, 10 [445, 222, 89, 44]	± 5, 2.5, 1, .5 [127, 64, 25, 13]	MTS 458	2 Years	Non-NEES
Large Bearing  Test Machine	Comp. : 1600 [7117.2] Lateral : 220 [978.6]	± 5 [127]	MTS 458	As Needed	Non-NEES
Small Bearing Test Machine	Vertical : 140 [622.8] Horizontal : 55 [244.7]	Horiz. ± 6 [152.4]  Rotational ± 2°	MTS 406	As Needed	Non-NEES
Tinius Olsen Universal Testing Machine*	300, 150, 80, 40, 20 [1335, 667, 356, 178, 89]	60 in. [ 1.52]	Tinius Olsen	2 Years	Non-NEES

* Machines force and displacement calibration can be adjusted for greater sensitivity.
** Fees will not be applied to scheduled NEES projects. Fees wil be charged for extra unscheduled time. Disclaimer: The rates are direct costs only and DO NOT include a 57% Department fee for administration and university fees. This overhead has to be added in estimates.

2.3.1 150 kip (667 kN) Tension Machine

This is a low speed machine capable of tension or compression testing of specimens or components composed of steel, concrete, rubber or other materials. The force range is adjustable to calibrated ranges of 200, 100, 40, and 20 kips, and the displacement range is adjustable to ± 4, 2, 1, and .5 in. for applications where greater sensitivity is required. The machine can be controlled in either force or displacement mode.



Figure 15 : View of 150 kip (667 kN) Tension Machine (click to enlarge)

2.3.2 Axial-Torsion MTS Machine

This machine is capable of biaxial testing of specimens and components of many sizes, up to 4 ft. (1.22 m) in length. Control modes available are force, strain and displacement in axial mode, and torque (in.lb.), strain and rotation (degrees) in torsion mode. The machine has calibrated ranges of 100, 50, 20, and 10 kips, and ± 5, 2.5, 1, and .5 in. axially, as well as 50000, 25000, 10000, and 5000 inch-pounds, and 50, 25, 10, and 5 degrees in the torsion mode.

Figure 16 : View of Axial-Torsion MTS Machine (click to enlarge)

2.3.3 Large Bearing Testing Machine

This machine has been developed for the testing of sliding bearings. It is capable of 1600 (7117.2 kN) kips compression (expandable to 2200 kips / 9786.1 kN), lateral load of up to 220 kips (978.6 kN), stroke of ± 5 in. (12.7 cm) and velocities of up to 10 in./sec (254 mm/sec). Bearing plan dimensions can be up to 45 in. (114.3 cm) by 45 in. (114.3 cm). It can be used for the seismic testing of sliding bearings and the characterization of frictional properties of large-dimension material interfaces. The machine can also be used for the testing of elastomeric bearings. The machine is capable of testing pairs of bearings, or a single bearing with the use of rolling cylinders. Figure 9 presents a view of this testing machine.

Figure 17 : View of Large Bearing Testing Machine (click to enlarge)

2.3.4 Small Bearing Testing Machine

This machine has been developed for the testing of single bearings under controlled conditions of vertical load, lateral movement and rotational movement. It has a 140 kip (622.8 kN) vertical load capacity, 55 kip (244.7 kN) horizontal load capacity, ± 6 in. (15.24 cm) horizontal movement capacity with up to 15 in./sec (381 mm/sec) velocity, and rotational capability of ± 2 degrees. Reaction forces can be directly measured by a multi-component load cell which currently has a rated capacity of 20 kips (89 kN) shear and 50 kips (222.4 kN) axial load. The machine can been used in the testing of elastomeric and sliding bearings, including tests under variable axial load and tests of bearings pre-stressed by tendons to prevent uplift. Figure 10 presents a view of the testing machine during testing of an elastomeric bearing.

Figure 18 : View of Small Bearing Testing Machine during Testing of an Elastomeric Bearing (click to enlarge)

2.4 Tinius Olsen Universal Test Machine

This machine has been used primarily for testing concrete cylinders, structural steel members, and standard steel test specimens. The machine consists of a dual crosshead, mechanical screw load frame, with a test surface platen having an effective area of 31 in. (79 cm) x 43 in. (109 cm). The platen is 45 in. (114.3) from the lab floor. The crossheads can be placed at any height along the screws to allow testing of specimens up to 72 in. (183 cm) long in tension. The upper crosshead is locked in place during testing, while the lower crosshead moves along the machine's screws to apply tension or compression to the specimen. Compression testing capacity is limited by the tendency of tall specimens to buckle, but theoretically a 72 in.(183 cm) specimen can also be tested in compression. The machine is capable of testing specimens in tension or compression to 300 kips (1334 kN). Force readout is provided by a dial indicator calibrated in ranges of 3, 12, 60 and 300 kips (13. 53, 267, and 1334 kN). For electronic readout, any suitable load cell can be mounted in series with the test specimen. Alternatively, a Temposonic displacement transducer is mounted on the gear rack assembly which drives the dial indicator, providing a linear voltage readout proportional to the position (force readout) of the dial indicator. Displacement readout is accomplished by using displacement transducers of suitable range mounted parallel to (or directly on) the test specimen.

Figure 19 : View of Tinius Olsen Universal Test Machine (click to enlarge)

2.5 Transducers

A number of different types of transducers are used throughout the laboratory, including those that measure load, displacement, rotation, acceleration and strain.

2.5.1 Load Measurement

Load Cells

Due to the fact that many of the test apparatuses are specifically developed for single experiments, in-house custom built load cells are often used. The geometric layout of a typical load cell is shown in Figure 11. They are fabricated from a thick wall cylindrical steel tube. The turned down wall thickness, height, and radius are determined based on the expected maximum stresses in the load cells during testing.

Figure 20 : Geometric Layout of Typical Load Cell (click to enlarge)

The attachment plates ensure a uniform stress distribution over the entire load cell and provide anchorage into the columns.
In the most complicated custom built load cells, axial, shear, and moment stresses can be measured from Wheatstone bridge circuits wired according to Figure 12. Simpler compression-tension load cells are also commonly built using only an axial Wheatstone bridge circuit.
In addition a majority of the MTS, Miller, and Parker Actuators were purchased with a load cell provided by the manufacturer. These load cells are often used in experimentation.

Delta P Cells

Delta P cells are used on many of the actuators available in the laboratories. The MTS servo controllers utilize the Delta P (differential pressure) measured across the actuator piston as a stabilizing variable during the control of an actuator's motion.

Table 6 lists the different available load measuring devices.

Table 6 : Available Load Measuring Devices
 

Load Measuring Device Type	Quantity	Load Capacity kips [kN]	Use	Calibration Interval	Equipment Designation *
Multi-Component (axial, x & y shear, x & y moment)	5	Axial : 50 [222.4] Shear : 20 [89]	Shake Table & Floor Testing	As Needed	Non-NEES
Axial (compression:tension)	10	2 : 250	Shake Table & Floor Testing	As Needed	Non-NEES
Washer (compression only)	8	100 [444.8]	Shake Table & Floor Testing	As Needed	Non-NEES
MTS Load Cell	1	2.2 [9.79]	On MTS Actuator	2 Years	Non-NEES
MTS Load Cell	2	55 [244.65]	On MTS Actuator	2 Years	Non-NEES
MTS Load Cell	1	110 [489.30]	On MTS Actuator	2 Years	Non-NEES
MTS Load Cell	1	220 [ 978.61]	On MTS Actuator	2 Years	Non-NEES
Miller Load Cell	2	250 [ 1112.06]	On Miller Actuator	2 Years	Non-NEES
Custom Built Load Cell	4	70 [311.38]	On Parker Actuator	As Needed for Experiments	Non-NEES
MTS Load Cell Model 661.31E-01	3	220	On MTS Actuator	2 Years	NEES
MTS Differential Pressure Cell 660.23	5	5000 psi	On MTS Actuator	2 Years	NEES

* Fees will not be applied to scheduled NEES projects. Fees wil be charged for extra unscheduled time. Disclaimer: The rates are direct costs only and DO NOT include a 57% Department fee for administration and university fees. This overhead has to be added in estimates.
 
 

Figure 21 : Typical Strain Gage Positioning and Wiring for Multidirectional Load Cells (click to enlarge)

2.5.2 Displacement Measurement

The laboratory uses many different types of displacement transducers that each have various attributes and limitations which determine their suitability for different applications. The following is a list of each different displacement transducer and a brief summary of its mechanics.

The most readily available and simplest position transducer is a linear potentiometer excited by a DC source such as a battery. It may be hooked up to deliver an output voltage that is essentially proportional to a straight-line position varying between zero and a maximum. Alternatively, a potentiometer may be hooked up to deliver an output varying between a negative and positive voltage in proportion to a mechanical displacement that also varies between a maximum negative and a maximum positive value relative to a defined null position.

The word "linear" appears in the name of the LVDT to denote straight-line motion as opposed to a linear relationship between input and output. Three coils of electrically conducting wire are wound on an insulating form. By the principle of mutual inductance an AC voltage across the terminals of the primary coil induces a voltage of the same frequency in each of the two secondary coils. If the moveable ferromagnetic core is centered, the two secondary voltages are of the same amplitude. For a positive displacement of the core, the voltage appearing across the number 1 secondary coil is greater in amplitude than at the null condition, while the amplitude across the number 2 secondary coil is less.

Initially a current pulse is applied to the conductor within the waveguide over its entire length. There is another magnetic field generated by the permanent magnet that exists only where the magnet is located. This field has a longitudinal component. These two fields join vectorially to form a helical field near the magnet which in turn causes the waveguide to experience a minute torsional strain or twist only at the location of the magnet. This torsional strain pulses propagates along the waveguide at the speed of sound in this material. When this torsional pulse arrives at the tapes in the head it is converted into a dynamic longitudinal pulse injected into the tapes. The longitudinal pulse cause the tapes to experience a momentary change in reluctance. Two coils coupling these tapes mounted in the field of two bias magnets will generate a momentary electrical pulse caused by the change in reluctance in the tapes. In order to extract the useful position information we measure the time between when we launch the initial current pulse and the time we receive the signal from the output coils. This time is a very precise function of the position of the moving magnet.



Figure 22 (click to enlarge)

2.5.3 Rotation Measurement

The laboratory uses rotational transducers that also have various attributes and limitations which determine their suitability for different applications. The following is a brief summary of its mechanics.

• Rotary Variable Differential Transformer (RVDT)

The principle of the LVDT has also been adapted for angular position measurement in a device known as a RVDT. A cardioid-shaped cam of magnetic material is used as a core, the shape of which is carefully chosen to produce a highly linear output over a specified range of rotation.

2.5.4 Acceleration Measurement

The laboratory also uses accelerometers in many of the experiments it conducts. The following is a list of each different accelerometer used and a brief summary of its mechanics.

• Piezoelectric Accelerometer

This accelerometer senses the absolute motion of an object or point in inertial space. They measure the acceleration aspect of shock and vibratory motion relative to an initial or average level, usually zero. However, this type of accelerometer requires the use of a charge amplifier. Also, note that due to the poor low frequency characteristics of this type of accelerometer, the laboratory is phasing out use of the remaining inventory.

• Piezoresistive Accelerometer

This type of accelerometer, also known as a strain gage accelerometer, is similar in principle to a piezoelectric accelerometer except it is equipped with a built in resistor, which allows it to be used with a standard signal conditioner.

Table 7 presents a summary of the available transducers (excluding load cells) and their range of measurement.

Table 7 : Available Transducers
 

Device Type	Measured Quantity	Quantity	Measurement Range	Equipment Designation *
Linear potentiometer	Displacement	20	± .25 : ± 2.0 in. [± .64 : 5.08 cm]	Non-NEES
LVDT	Displacement	15	± .5 : ± 2.0 in. [± 1.27 : 5.08 cm]	Non-NEES
MTS Temposonic Transducer	Displacement	15	4 in. [10.16 cm]	Non-NEES
MTS Temposonic Transducer	Displacement	4	8 in. [20.32 cm]	Non-NEES
MTS Temposonic Transducer	Displacement	3	10 in. [25.4 cm]	Non-NEES
MTS Temposonic Transducer	Displacement	4	16 in. [40.64 cm]	Non-NEES
MTS Temposonic Transducer	Displacement	7	20 in. [50.8 cm]	Non-NEES
MTS Temposonic Transducer	Displacement	2	30 in. [76.2 cm]	Non-NEES
Shaevitz RVDT	Rotation	4	0 : 30 degrees	Non-NEES
Endevco Piezoresistive Accelerometer	Acceleration	8	0 : 25 g	Non-NEES
Sensotec Piezoresistive Accelerometer	Acceleration	15	0 : 10 g	Non-NEES
Kulite Piezoresistive Accelerometer	Acceleration	15	0 : 10 g	Non-NEES
MTS Temposonic II	Displacement	15	4-20 in.	NEES

* Fees will not be applied to scheduled NEES projects. Fees wil be charged for extra unscheduled time. Disclaimer: The rates are direct costs only and DO NOT include a 57% Department fee for administration and university fees. This overhead has to be added in estimates.

2.6 Signal Conditioners

Listed below are the available signal conditioning channels, charge amplifiers and power supplies. Table 8 presents a summary of the available equipment.

• 90 channels of Measurement Group 2300 DC Series signal conditioning which can be used with full, half, and quarter bridge configurations. This signal conditioner allows the use of either 120 or 350 ohm strain gages in a quarter bridge configuration and the amplification can be set in the range of 1 to 11000. The excitation voltage can be easily adjusted using a front panel control in the range of 0.7 to 15.0 volts.

• 20 channels of Measurement Group 2100 DC series signal conditioning which can be used with full, half, and quarter bridge configurations. This signal conditioner allows the use of either 120 or 350 ohm strain gages in a quarter bridge configuration and the amplification can be set in the range of 1 to 220. The excitation voltage can be easily adjusted using a front panel control in the range of 0.0 to 10.0 volts.

• Miscellaneous DC power supplies, built in - house, are used to supply input voltage to linear potentiometers and Temposonic Displacement Transducers (section 2.5.2). They are built, configured and maintained as needed.

Table 8 : Available Signal Conditioners
 

Signal Conditioner Type	Number of Channels	Gain Range	Bridge Configurations Supported	Quarter Bridge Strain Gage Resistance (Ohms)	Excitation (volts)	Equipment Designation
Measurement Group 2300 DC	90	1-11000	Full, Half, Quarter	120, 350	0.7-15.0	Non-NEES
Measurement Group 2100 DC	20	1-220	Full, Half, Quarter	120, 350	0.0-10.0	Non-NEES
Generic Potentiometer power supply	20	NA	NA	NA	± 10.0	Non-NEES
Generic Temposonic power supply	35	NA	NA	± 15.0	15.0	Non-NEES
Misc. (standalone charge amps, etc.)	15	NA	NA	NA	NA	Non-NEES

2.7 Data Acquisition

• Pacific Instruments 6000 Data Aquisition Mainframe

The 6000 Mainframe has an IEEE-488 interface for control and data output with mounting for 16 input and output modules. It supports up to 31 additional slave enclosures or up to 32,000 channels. Currently it is configured for 256 channels.

Figure 23: Pacific Instruments 6000 Data Aquisition Mainframe(click to enlarge)

• Krypton K600 Portable CMM System

The K600 is a new generation of high performance dynamic mobile coordinate measurement machine. The system combines high accuracy, a large measurement volume and full freedom of Space Probe manipulation. This solid-state system is extremely reliable.

Figure 24: Krypton K600 Portable CMM System(click to enlarge)

List of Supporting documantation:

• Krypton Help Pages on K600 (Hardware and Software guide)
• Krypton Help Pages on K-CMM
• User Manual on K-Assist 1.7
• Krypton Help Pages on Geoloc
• Krypton Help Pages on DMM Modular

• Optim Megadec 16 Bit Data Acquisition Mainframe

  This is a modular, expandable system, currently configured with 128 channels of sample & hold A/D input, along with 8 channels of thermocouple conditioning and 8 output channels for monitoring. The Megadac is primarily used in the original Seismic laboratory for various test programs.

• Dell Optiplex Workstations with National Instruments/LabView Data Acquisition

  These systems (3 total) each consist of 16 channels of National Instruments 16 bit data acquisition input channels, 4 analog output channels, and LabView 7 Express data acquisition development system. The systems are portable and can be used in the NEES/SEESL environment as well as in the various teaching labs located throughout CSEE.

• Intel Pentium II PC & Data Translation 12 bit Desktop System

  The lab supports a varying number of these systems. They are configured as needed for up to 32 channels per PC. As the previously mentioned Dell/LabView systems are being phased into service, these systems will gradually be taken out of service due to obsolescence of hardware and software components.

2.8 Oscilloscopes

The laboratories currently support two 4-channel storage oscilloscopes, used mostly for instrumentation calibration and verification of signal integrity. One of the oscilloscopes, a Tektronix model TDS224, has storage and data acquisition functionality.

2.9 4 Channel Analog/Digital Frequency Analyzer

(under development)

2.10 Digital Multimeters and Voltage Standards

The lab maintains several digital multimeters, all of which are calibrated annually and are used as reference standards for in-house calibrations. Calibration data sheets are available to users who wish to verify quality of measurements.

2.11 Computers

A local area network based on the Novell Netware operating system was developed in the seismic lab in 1993 and since has been replaced with a Windows 2000/2003 Server - based network. The network functions as a warehouse for the numerous data files acquired during testing in the Ketter Hall labs. The seismic lab houses a variety of personal computers configured primarily for data acquisition and test control. The CPU' s range anywhere from Pentium II 400 MHz (simple data acquisition tasks) to Pentium IV 3.3 GHz (used for complex control applications). All lab computers are connected to the lab network; in addition, the network is available to all users associated with the lab (faculty, staff, and graduate students) from their office PC's or from the public computing labs in Ketter Hall. The number and capability of the lab computers is not fixed; computers are added and deleted as needs dictate. The laboratory network (LAN) is interfaced with the Civil, Structural and Environmental Engineering LAN named "CSEE”, the research LAN for structural control and nonlinear dynamics named "STRUCTDYNAMICS", and with the research LAN for Network for Earthquake Engineering Simulation "NEES". "The STRUCTDYNAMICS" and "NEES" LANs are equipped with high speed workstations for data processing. The multiple servers and storage devices provide permanent data storage and access, e-mail, internet access, and homepages. Also there are two NEES dedicated servers, a Telepresence server (NEES TPM) and NEES POP server. Both of these machines are DELL PowerEdge 2650 servers with Dual Xenon 2.4GHz processors and 2GB of RAM.

Figure 24: Server Room(click to enlarge)

The homepage for NEES/SEESL can be found at http://nees.buffalo.edu.