A model for predicting narrow tool behavior under dynamic conditions

Most models available today for predicting the forces encountered by tillage tools apply to slow moving tools and do not take into account speed effects. However, most tillage operations are performed at speeds in the range of 2-8 km/h, and experimental studies show that tool forces increase signifi...

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Bibliographic Details
Main Author: Swick, W. Christopher
Other Authors: Agricultural Engineering
Format: Others
Language:en_US
Published: Virginia Polytechnic Institute and State University 2017
Subjects:
Online Access:http://hdl.handle.net/10919/80134
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spelling ndltd-VTETD-oai-vtechworks.lib.vt.edu-10919-801342020-09-29T05:47:54Z A model for predicting narrow tool behavior under dynamic conditions Swick, W. Christopher Agricultural Engineering LD5655.V855 1984.S988 Shear strength of soils -- Testing Shear strength of soils -- Mathematical models Tillage -- Testing Most models available today for predicting the forces encountered by tillage tools apply to slow moving tools and do not take into account speed effects. However, most tillage operations are performed at speeds in the range of 2-8 km/h, and experimental studies show that tool forces increase significantly with tool speed. This effort of developing a model for predicting the forces on narrow tools under dynamic conditions was carried out in three steps. First, a series of laboratory tests was conducted to determine the effect of shear rate on soil shear strength and soil-metal friction parameters. Second, a model was developed to include dynamic effects. Third, the model was verified experimentally under laboratory conditions. Direct shear tests using a conventional shear box were conducted on an artificial soil at shear rates between 0. 5 and 12 7 cm/min. Experimental results showed that for the soil tested, the angle of internal friction, soil-metal friction angle, cohesion, and adhesion are independent of shear rate. A soil-tillage tool interaction model developed for quasi-static soil failure was modified to include shear rate effects and accelerational force effects. Experimental verification tests for the model were conducted under controlled conditions using an indoor soil bin facility. Tests were conducted with flat tines at speeds from 5. 4 to 120 cm/s. The overall trend was for the model to underpredict the observed total tool force by 16 %. However, the model demonstrated that terms including accelerational force effects can account for a large portion of the increase in tool force observed to occur with an increase in tool speed. Master of Science 2017-11-09T21:09:06Z 2017-11-09T21:09:06Z 1984 Thesis Text http://hdl.handle.net/10919/80134 en_US OCLC# 11704649 In Copyright http://rightsstatements.org/vocab/InC/1.0/ ix, 95 leaves application/pdf application/pdf Virginia Polytechnic Institute and State University
collection NDLTD
language en_US
format Others
sources NDLTD
topic LD5655.V855 1984.S988
Shear strength of soils -- Testing
Shear strength of soils -- Mathematical models
Tillage -- Testing
spellingShingle LD5655.V855 1984.S988
Shear strength of soils -- Testing
Shear strength of soils -- Mathematical models
Tillage -- Testing
Swick, W. Christopher
A model for predicting narrow tool behavior under dynamic conditions
description Most models available today for predicting the forces encountered by tillage tools apply to slow moving tools and do not take into account speed effects. However, most tillage operations are performed at speeds in the range of 2-8 km/h, and experimental studies show that tool forces increase significantly with tool speed. This effort of developing a model for predicting the forces on narrow tools under dynamic conditions was carried out in three steps. First, a series of laboratory tests was conducted to determine the effect of shear rate on soil shear strength and soil-metal friction parameters. Second, a model was developed to include dynamic effects. Third, the model was verified experimentally under laboratory conditions. Direct shear tests using a conventional shear box were conducted on an artificial soil at shear rates between 0. 5 and 12 7 cm/min. Experimental results showed that for the soil tested, the angle of internal friction, soil-metal friction angle, cohesion, and adhesion are independent of shear rate. A soil-tillage tool interaction model developed for quasi-static soil failure was modified to include shear rate effects and accelerational force effects. Experimental verification tests for the model were conducted under controlled conditions using an indoor soil bin facility. Tests were conducted with flat tines at speeds from 5. 4 to 120 cm/s. The overall trend was for the model to underpredict the observed total tool force by 16 %. However, the model demonstrated that terms including accelerational force effects can account for a large portion of the increase in tool force observed to occur with an increase in tool speed. === Master of Science
author2 Agricultural Engineering
author_facet Agricultural Engineering
Swick, W. Christopher
author Swick, W. Christopher
author_sort Swick, W. Christopher
title A model for predicting narrow tool behavior under dynamic conditions
title_short A model for predicting narrow tool behavior under dynamic conditions
title_full A model for predicting narrow tool behavior under dynamic conditions
title_fullStr A model for predicting narrow tool behavior under dynamic conditions
title_full_unstemmed A model for predicting narrow tool behavior under dynamic conditions
title_sort model for predicting narrow tool behavior under dynamic conditions
publisher Virginia Polytechnic Institute and State University
publishDate 2017
url http://hdl.handle.net/10919/80134
work_keys_str_mv AT swickwchristopher amodelforpredictingnarrowtoolbehaviorunderdynamicconditions
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