A University of Nevada, Reno Mechanical Engineering Capstone Project In Cooperation with Lawrence Livermore National Laboratory
Division By Zero
Project Background
The Defense Technologies Engineering Division at Lawrence Livermore National Laboratory (LLNL) conducts material testing in support of the National Nuclear Security Administration's Stockpile Stewardship Program. A load frame is used to apply a compressive load of up to 30,000 lb to test assemblies on a precision granite table during testing. LLNL's current load frame is permanently mounted to the granite table which inhibits use of the table for activities other than load testing. A mobile load frame with the same functionality as the current load frame which can be removed from the granite table and securely stored elsewhere in the facility provides the ideal solution.
Budget
$10,000 to produce a working prototype
Materials, components, and outsourced manufacturing and finishing brought the final cost of the prototype to $9,500. Much of the machining and assembly was accomplished in UNR's Mechanical Engineering Manufacturing Lab, keeping costs down.
Functionality
Load, dimensional, and operational usage
The load frame must be capable of applying a 15,000 lb load to a test assembly without failure for the extent of its useful life.
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The test space must be able to accept test assemblies up to 12 inches in diameter and 18 inches tall.
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The load frame must interface with test assemblies, a powered hydraulic system, a data acquisition system to read load cell output, and fit on and attach to the granite table at LLNL's testing facility.
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Mobility
Features allowing movement
Lifting points enable an overhead gantry crane to lift and carry the load frame between the granite table and its storage crate.
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The base plate attaches to the granite table and interlocks with the load frame feet during use.
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Air bearings in the feet allow the load frame to move easily while being positioned on the granite table.
Safety
Measures to protect personnel
Protective covers enclose the belt drive system that provides simultaneous rotation of the screws during crosshead positioning.
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Hazard areas in the upright channels are not easily accessible during use, reducing the likelihood of injury.
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The prototype conforms to 29 CFR 1910.399 for use in Class II Division 2 locations with airborne explosive particulate.
Storage
Security when not in use
A storage crate provides secure storage for the load frame and accessories when not in active use.
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Project Requirements
LLNL provided Division By Zero with 31 requirements for the project in the areas of budget, functionality, mobility, safety, and storage. The prototype is half-scale and so would require a load capacity of 15,000 lb.