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Laboratory Studies Into Undercarriage Systems Table 3: Rut parameters for different forward speeds, statistically identical values are followed by the same letter (a, b or c) 3.1.2.4 Discussion and Conclusion Treatment Area (m 2 ) Width (m) Max. Depth (m) 900/5/0.5 at 0.28 m/s 0.0276 a 0.81 a 0.07 a 900/5/0.5 at 0.85 m/s 0.0179 b 0.68 b 0.055 b 900/5/0.5 at 1.52 m/s 0.0168 b 0.69 b 0.053 b LSD 0.0037 0.037 0.007 The data showed the significant influence of speed on soil displacement. Aboaba (1969) did not give an explanation why this was the case. Assuming soil could physically be described as a damper-spring system, this behavior would be due to the time depending elon- gation of the damper. The longer a force is applied, the more the damper contracts, i.e. soil compacts. The speed of 0.85 m/s used in the soil bin created marginally more soil displacement than common harvest speed at about 1.5 m/s. If the speed was significantly re- duced to 0.29 m/s, the impact would be bigger. Thus 0.85 m/s was considered a reasonable compromise between operational safety and the replication of real speeds. The result of a speed at 0.29 m/s compared to the other two visualizes the possible damage occuring in headlands originating from slower speed. 3.1.3 Gravimetrically Measured Dry Bulk Density Dry bulk density was measured for all experiments gravimetrically as described in Section 2.2.3.1. However, due to the large variations reported by Ansorge and Godwin (2007) details on gravimetrically measured dry bulk density are only given in the Appendix 2. The sensitivity of the soil displacement measurement was significantly greater and therefore the focus will be on that measure. Ph.D. Thesis Dirk Ansorge (2007) 36
Laboratory Studies Into Undercarriage Systems 3.2 Evaluation of Implement Tyres and Whole Combine Harvesters Following Ansorge (2005, a) it was important to investigate the effect of the additional passage of the rear tyre on the soil when considering whole machines. Particularly interest- ing was the question whether the advantage gained by using tracks at a total load of 12 t in comparison to tyres at a total load of 10.5 t (the smaller load accounts for the lighter undercarriage system) could be maintained after the passage of a rear tyre at a load of 4.5 t. To conduct this study first rear tyres are evaluated on their own. Details of the rear tyre specifications including the load of 4.5 t and the corresponding inflation pressure are shown in Table 4. The abbreviation used for the single rear tyres is listed, too. Table 4: Rear tyre specifications Tyre Load (t) Inflation Pressure (bar) Abbreviation 500/70 R24 4.5 2.3 500-70/4.5/2.3 500/85 R24 4.5 1.4 500-85/4.5/1.4 600/55 – 26.5 4.5 1.4 600/4.5/1.4 710/45 – 26.5 4.5 1.0 700/4.5/1.0 Afterwards whole common combine harvester undercarriage system comparisons will be conducted. Additional machine configurations will be investigated as detailed in Figure 1. Table 5 gives a listing of all the simulated machine configurations with tyre, track, load, and inflation pressure combinations and assigns an abbreviation to each. The 680-700 was assumed to act as a dual tyre configuration on the front axle. Due to the width restriction of the soil bin, no true dual configuration with two 680 tyres side by side could be realized. Hence, the load was halved for one tyre and for simplicity no interaction between the two tyres was assumed. This assumption is justified due to the punching type of soil failure already observed by Ansorge (2005, a) and explained in Section 7.5. Ph.D. Thesis Dirk Ansorge (2007) 37
Page 1 and 2: Cranfield University School of Appl
Page 3 and 4: Abstract Ancillary experiments show
Page 5 and 6: Table of Contents TABLE OF CONTENTS
Page 7 and 8: Table of Contents 4.1.3 Analysis of
Page 9 and 10: Table of Contents 11.1.1.1 Comparis
Page 11 and 12: List of Figures and Tables Figure 3
Page 13 and 14: List of Figures and Tables Figure 1
Page 15 and 16: Nomenclature NOMENCLATURE Abbreviat
Page 17 and 18: Introduction 1 INTRODUCTION 1.1 Bac
Page 19 and 20: Introduction � Ansorge, D. and Go
Page 21 and 22: Introduction 1.2 Aim To elucidate t
Page 23 and 24: Introduction a) the soil compaction
Page 25 and 26: Experimental Methods 2.1.1.1 Test F
Page 27 and 28: Experimental Methods had been mount
Page 29 and 30: Experimental Methods track; the loa
Page 31 and 32: Experimental Methods 800/10.5/2.5 t
Page 33 and 34: Experimental Methods term. In the m
Page 35 and 36: Experimental Methods Soil Surface F
Page 37 and 38: Experimental Methods Depth (cm) 0 1
Page 39 and 40: Experimental Methods ence surface c
Page 41 and 42: Experimental Methods chine derives
Page 43 and 44: Experimental Methods depth. The dat
Page 45 and 46: Experimental Methods with water and
Page 47 and 48: Experimental Methods 2.4 Statistica
Page 49 and 50: Laboratory Studies Into Undercarria
Page 51: Laboratory Studies Into Undercarria
Page 77 and 78: Field Study With Full Size Combine
Page 99 and 100: Alleviation of Soil Compaction Howe
Page 101 and 102: Alleviation of Soil Compaction not
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Alleviation of Soil Compaction in a
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Alleviation of Soil Compaction diff
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Soil Compaction Models sibilities t
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Soil Compaction Models depends on t
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Soil Compaction Models Wroth (1968)
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Soil Compaction Models however, the
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Soil Compaction Models level. Criti
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Soil Compaction Models Utilizing Ke
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Soil Compaction Models average of m
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Soil Compaction Models Depth (mm) -
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Soil Compaction Models ture content
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Soil Compaction Models with four ot
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Soil Compaction Models Predicted In
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Soil Compaction Models Depth (mm) -
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Soil Compaction Models and 13.7 % b
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Soil Compaction Models Rel. Density
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Soil Compaction Models VCL paramete
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Soil Compaction Models The approach
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Soil Compaction Models surface stay
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Soil Compaction Models This result
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Soil Compaction Models 6.6.1.3 Wate
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Soil Compaction Models σσ 1 (kPA)
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Soil Compaction Models pressure to
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Soil Compaction Models The response
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Soil Compaction Models On medium so
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Soil Compaction Models SOILFLEX tak
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Ancillary Experiments 7 ANCILLARY E
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Ancillary Experiments Average conta
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Ancillary Experiments In order to c
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Ancillary Experiments contrary, the
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Ancillary Experiments Figure 102: S
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Ancillary Experiments track and the
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Ancillary Experiments even when hav
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Ancillary Experiments 7.3.2 Influen
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Ancillary Experiments The results f
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Ancillary Experiments Figure 117: S
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Ancillary Experiments Contact Press
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Ancillary Experiments Figure 123: F
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Ancillary Experiments Sinkage (mm)
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Ancillary Experiments model which o
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Ancillary Experiments 7.3.5 The Inf
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Ancillary Experiments 7.3.7 Discuss
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Ancillary Experiments Terzaghi (194
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Ancillary Experiments contact area.
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Ancillary Experiments soil forward
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Conclusions � The longitudinal so
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Bibliography 10 BIBLIOGRAPHY Aboaba
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Bibliography Defossez, P., Richard,
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Bibliography Gregory, A.S.; Whalley
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Bibliography Lamande, M., Schjonnin
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Bibliography Seig, D., 1985. Soil C
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Appendix 11 APPENDIX Ph.D. Thesis D
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Appendix Figure 32: VCL sample at t
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Appendix comparison at the deepest
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Appendix Estimated Pressure (kPa) 2
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Appendix 11.1.1.2.1 SOCOMO One of t
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Appendix by Seig (1985) who showed
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Appendix Soil water content 15 % an
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Appendix Adapting critical state so
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Appendix density is obtained by add
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Appendix Table 5: Values of constan
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Appendix choice of a concentration
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Appendix 11.1.3.1 Dense/Hard and Lo
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Appendix 11.1.3.2 Stratified Soil C
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Appendix To summarize the ability t
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Appendix In the following the predi
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Appendix concentration factor of 4,
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Appendix 11.1.5.1 Confining Pressur
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Appendix Figure 24. The VCL created
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Appendix Rel. Density 2 1,9 1,8 1,7
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Appendix relation of � 1 to � 2
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Appendix Rel. Density 2 1,9 1,8 1,7
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Appendix Rel. Density 1,7 1,68 1,66
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Appendix Depth (mm) 0,0 100,0 200,0
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Appendix Figure 42: Plate in cookin
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Appendix � z � � �� k c p
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Appendix Table 8: n and k depending
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Appendix to the plate sinkage equat
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Appendix with a slight deviation fr
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Appendix Table 12: DBD values for a
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