Degree Type

Dissertation

Date of Award

2008

Degree Name

Doctor of Philosophy

Department

Mechanical Engineering

First Advisor

J. Adin Mann, III

Second Advisor

James Bernard

Third Advisor

Don Flugrad

Abstract

A new method of evaluating tillage tools using computational fluid dynamics is proposed. Steady-state CFD only and transient two-way fluid-structure interaction simulations were run to predict draft and vertical forces on a spring-reset field cultivator standard. Using CFD the soil was treated as a visco-plastic fluid using the Bingham-plastic material model. Lab tests were run using a rigid flat steel bar and a production field cultivator standard with 178 and 254 mm sweeps for comparison. The results indicate that the method can be used to reasonably predict the draft force to within three standard deviations of the average measured draft. The method was successfully used to determine which sweep size created the higher draft forces. The method also was able to predict the areas on the tool with the highest pressure related to the locations that exhibit the highest wear. Soil parameters were measured using a standard technique, but modified values were needed to get good agreement between measured and calculated forces. An alternate method of measuring soil properties using a flat steel bar was therefore proposed. Further work is needed to determine if the modified soil properties were correct, requiring the new soil property measurement technique, or if the CFD method needs to be modified.

DOI

https://doi.org/10.31274/rtd-180813-17086

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Mark Eugene Barker

Language

en

Proquest ID

AAI3307054

OCLC Number

243603775

ISBN

9780549543015

File Format

application/pdf

File Size

193 pages

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