High_Speed_Tensile_Tester_Questions_and_Answers.docx

High Speed Tensile Tester Questions and Answers

1. In 3.2 (Load Train)(Hydraulic Lifts and Locks), does this mean that the entire pressure vessel is raised and lowered? Or that one end (say, the bottom) is held fixed, and the top (e.g. lid/cover) is raised to permit sample insertion and then lowered and sealed for testing?

A: The bottom would be held fixed and the top (lid/cover) raised to permit sample insertion.

2. Given that some type of propellant is to be tested under tension, are there any safety (e.g. flammability, explosion, or toxicity) concerns involved in handling the samples, loading them in air, unloading them, or subjecting them to pressure and temperature extremes? Is the absence of oxygen (via pump purging and confirmed via sensor monitoring) during testing a requirement?

A: Yes there are safety concerns when working with propellants. Sparks, electrostatic discharge, heat sources, extreme temperatures in excess of about 250°F, impact, and friction can all cause unintentional propellant ignition. Keeping all components at the same ground potential, limiting high temperature, avoiding situations that could pinch or impact propellant all reduce the risk. There is no oxygen sensitivity or need to eliminate oxygen. The propellant has its own oxidizers that allow it to burn in low to no oxygen environments. An over pressurization relief valve on the pressure vessel would be needed to limit the vessel to the 2000psi requirement.

3. Is the propellant laboratory and NEC classified location (Hazardous Location)?

A: The location for the test equipment is not classified as a hazardous location. It is licensed for propellant but the propellant is stable and difficult to ignite unless there is propellant dust. We have a machine shop that falls under this category but not the labs.

4. Given that 3.1 gives specifications for the laser extensometer, is it accurate to assume this is to be contractor-supplied and not government-supplied equipment?

A: Yes, the laser extensometer is supposed to be contractor supplied as part of the test system

5. Is it accurate to assume that the government expects the laser extensometer to be located outside the pressure vessel and operated through one of the window ports? This seems logical based on the language of 3.1 (Window Ports).

A: Yes, the laser extensometer is to be located outside the vessel and operated through one of the ports.

6. Has the government specified an accuracy classification (vis-à-vis ASTM E83) for the laser extensometer?

A: ASTM E83, class B1

7. Does the government prefer a particular style or technology of laser extensometer? Is the use of reflective tape on the sample permitted?

A: There is no preferred style or technology as long as it meets the requirements. Reflective tape is permitted

8. Does the specification to be able to integrate a video (through one of the other window ports) or clip-on extensometer (with electric feed-throughs) imply that the government plans to furnish video or clip-on extensometers, or is this future expansion capability? Is it correct to assume that specifications for either video or clip-on extensometers are not given, the contractor is not required to supply either?

A: Government will furnish video and clip-on extensometers. Contractor is not required to supply them.

9. In 3.2 (Load Train)(Alignment), is the required load train alignment verification to be performed simply when installing the pressure vessel into the load frame, or after loading each sample? Must it be monitored in real time during testing? Does the government have a preferred method for measuring/validating this alignment?

A: The alignment of the load train should be performed after installation to verify the system is pulling samples straight and uniformly. It does not need to be monitored real time. There is no preferred method from the Government. The system should remain aligned once alignment is accomplished.

10. What is the nature of the 10,000 lb maximum applied force requirement, given the largest load cell measures up to only 3000 lb?

A: The 10,000 lb maximum applied force requirement ensures a stiff frame and allows potential for future test requirements

11. Are the hydraulic ram speed and acceleration specifications based on a particular testing requirement, or are they reflections of the current test setup and/or the government’s understanding of currently available COTS products?

A: Speed and acceleration specifications are based on both testing requirements and a reflection of the current test setup. The government assumption is current COTS products can either meet or beat the existing system being used.