Tab_02_-_Statement_of_Work.pdf

Statement of Work Replacement UD T4000 Slip-table and Base Assembly or Equivalent

1.0 Background

NASA Langley Research Center requires a replacement slip-table and base assembly for an existing Unholtz-Dickie T4000 electrodynamic shaker .

2.0 Requirements

The Contractor shall provide all labor, materials, and equipment necessary to provide a slip-table and base assembly that meets all requirements specified herein.

2.1 General Requirements

1. The existing T4000 shaker and new slip table shall be mounted on a single base which will be used as a reaction mass

2. The Contractor shall integrate the existing T4000 shaker into the base/slip-table assembly

3. Total weight of the base and slip-table shall be no less than 36,000 pounds.

4. The contractor shall specify the interface requirements for connections between the system and facility utilities. The contractor shall submit these requirements with their quote.

2.2 Slip-Table Characteristics

1. The payload mounting area on the slip-table shall be no less than 52 x 52 inches.

2. The useable frequency range of the slip-table shall be no less than 5 to 2000 Hz.

3. The effective travel of the slip-table shall be no less than 2 inches.

4. The slip-table moving mass, including driver bar, shall be no greater than 600 lb

5. The payload mounting holes shall be located on a 4 x 4 inch grid. In addition to the grid pattern, a shaker load attach pattern, with the dimensions specified below shall be provided.

a. One insert at the center

b. 4 on a 4" bolt circle

c. 8 on an 8” bolt circle

d. 8 on a 12” bolt circle

e. 8 on a 16” bolt circle

f. 8 on a 24” bolt circle

6. Payload attachment shall be via ½-13 UNC stainless steel inserts.

7. The flatness of the table shall be within ±0.005 inches. The finish of the table shall be no less than 125 micro-inches.

8. The system shall be able to support the following overturning moments:

a. Pitch: 300,000 in-lbs

b. Roll: 150,000 in-lbs

c. Yaw: 145,000 in-lbs

9. The slip-table rated velocity shall be no less than 85 in/sec

10. The first no-load resonance frequency of the slip-plate shall be no less than 750 Hz

11. The minimum rated dynamic axial force (direction of motion) shall be no less than 40000 lb

12. To change from vertical to horizontal operation, it shall be only necessary to attach a driver bar to the armature and rotate the shaker 90°. The driver bar shall automatically align with the slip plate. No Further adjustments to the driver bar shall be required.

13. If the slip-table is supported on a flat surface, the surface shall be natural granite.

14. If a hydraulic system is used to support the table:

a. The hydraulic system shall be self-contained

b. All hardware shall be supplied including pump, filter, etc.

c. The slip plate shall be sealed so that dirt or water cannot contaminate the hydraulic fluid and the hydraulic fluid shall not migrate to the slip-table upper surface, shaker, or base surfaces

d. Oil hoses connected to the slip plate are not acceptable

15. The Contractor shall furnish a dimensioned drawing of the slip-plate in .dxf format.

2.3 Base Characteristics

1. The base shall be isolated from the floor by self-leveling air mounts.

2. In order to minimize pitching excitation of the base when driving the shaker vertically, the combined center of gravity of the shaker and base mass shall be located on the centerline of dynamic force (i.e. shaker centerline), ±20 inches.

3. The elastic center of the base isolation system shall coincide with a vertical line through the combined center of gravity, ±5 inches.

4. Resonant frequencies of the combined assembly on the base isolation mounts shall be low enough in frequency and sufficiently damped so that the shaker may be operated in the vertical mode with a 2,000 pound payload in the following manner:

Sine sweep @ 1.0 inch peak-to-peak displacement from 5 to 15 Hz. Cross action motion in any direction shall not exceed 10% of the vertical motion. This test is intended to determine if the pitching or rotational modes of the reaction mass are sufficiently damped. Floor vibration during this test is measured within three feet of the reaction mass shall not increase more than 5% above the ambient level

5. The shaker shall be isolated from the base at the rotation axis both in the vertical direction and the horizontal direction. When operating vertically, the isolation resonance shall be no greater than 3 Hz. Horizontally it shall be no greater than 2 Hz.

6. It shall be possible to operate the shaker at full performance with the shaker locked rigidly to the base or with the shaker isolated, both vertically and horizontally.

3.0 Acceptance Test

The Contactor shall propose, as part of the submittal, and perform an acceptance test of the combined shaker, slip-table, and base to demonstrate compliance with the requirements of this statement of work.

The acceptance may be performed at the vendor facility or installation site. The acceptance testing may be witnessed by a Government representative.