Date of Graduation

1998

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Mechanical and Aerospace Engineering

Committee Chair

Kenneth H. Means

Abstract

The purpose of this work was to model and test an intermediate material that would absorb impact loads induced during deployment of a deployable rollover protective structure (ROPS) designed for use on a farm tractor. The design criteria required that the intermediate material, under compressive loads, maintain the integrity of all moving parts while introducing a minimum impact time of 0.005 seconds. A "ring" shaped part made of 80-Derometer rubber (a product of the Goodyear Corporation) was incorporated into the impact region of the ROPS deployment mechanism. Theoretical calculations were made based on energy balance equations and 2-D Working Model software. Laboratory test data of the ROPS motion was collected during three separate deployments using an OPTOTRAK system as well as an accelerometer. Also a finite model of the ROPS was simulated as a means of obtaining additional information on the impact using LS-DYNA 3D. Data from the various sources was compared and showed consistency with theoretical parameters. The 1-inch thick rubber was compressed approximately 0.33 inches under an impact load of just over 6,700 pounds (s = 730 psi). The impact time on the rubber was found to be approximately 0.007 seconds while no appreciable damage was afflicted on the individual parts of the ROPS.

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