Simulation of sweep tillage using discrete element modelling
Başlık çevirisi mevcut değil.
- Tez No: 653084
- Danışmanlar: PROF. DR. DANIŞMAN YOK
- Tez Türü: Doktora
- Konular: Mühendislik Bilimleri, Engineering Sciences
- Anahtar Kelimeler: Belirtilmemiş.
- Yıl: 2014
- Dil: İngilizce
- Üniversite: University of South Australia
- Enstitü: Yurtdışı Enstitü
- Ana Bilim Dalı: Belirtilmemiş.
- Bilim Dalı: Belirtilmemiş.
- Sayfa Sayısı: 201
Özet
Tillage operations for agriculture are a vital part of crop production for both weed control and creation of a seed bed. Economic and environmental considerations are forcing farmers to manage soil tillage with an optimum tool configuration to get a desirable soil condition. Energy used for tillage processes accounts for a significant proportion of total energy usage in crop production. Understanding tillage tool design parameters will help with tillage tool design and selection. Although some experimental and numerical studies can be found in the literature to simulate soil-tool interactions, none of them give accurate results when the dynamic effects of moving soil are considered. In addition, none of them can predict the changes in soil structure and translocation with high accuracy. Modelling of soil-tool interaction is a complex process due to the variability of the soil profile, non linear behaviour of the soil material, and the dynamic effect of the soil flow. An approach that will give further insight is the technique of discrete element modelling (DEM). DEM is now an effective simulation modelling tool for bulk handling of minerals and agricultural products and has the potential to accurately simulate soil-tool interaction. It examines the dynamics of discrete particles in a granular media and solves engineering problems that are modelled as a large system of discrete interacting bodies or particles subjected to gross motion. Although there are a few articles related to 3D DEM of soil-tool interaction, none of them have considered the plastic deformation behaviour of the soil, soil cohesion and adhesion. Therefore, past work can only be used for incomplete estimation of the tillage operations. Almost all of the past literature has been focused on predicting draft forces and no satisfactory prediction has been found in the literature regarding the vertical force prediction. In addition, there is no study in the literature that predicts from first principals the resulting furrow profiles. iii In this study the software EDEM was used to model the action of shallow working sweep wing tillage tools that have been previously studied at UniSA with regards to tillage forces and furrow profile by Fielke (1988). The approach was firstly to examine a non-cohesive soil that does not adhere to the tool and to then include cohesion and adhesion to the model. Results were compared to past field tests, experimental glass sided bin tests, and finite element modelling (FEM) results. In previous 3D DEM tillage studies the soil particles were assumed as having pure elastic contacts and as such, the plastic deformation behavior of the soil particles was not taken into account. This study compared a non-linear elastic contact model with a linear hysteretic spring contact model that considers the plasticity of the soil. The DEM parameters required to run the simulations were determined by performing an angle of repose and two penetration tests, matching the simulation results to test results using a modeled spherical particle with radii of 10 mm for both contact models. A better correlation with measured draft and vertical force results was obtained using the linear hysteretic spring (plastic) contact model. Further simulations were made using the linear hysteretic spring (plastic) model that showed there was a quadratically increasing trend with particle size from 4 to 10 mm for the DEM parameters of coefficient of restitution of soil-soil, friction of soil-soil and the required integration time step. The tillage forces and the furrow profile for a sweep tool was also simulated for varying geometries and speeds to validate the hysteretic contact model and parameters. The simulation results were compared to Fielke (1988)'s experimental sweep results for varying width and rake angles. A good correlation was obtained between the predicted and measured tillage forces for both draft and vertical forces (R2= 0.90 to 0.95) and a fair correlation (R2= 0.65 to 0.90) was obtained between the predicted and measured furrow profile data. Of the furrow profile parameters, the width cut was closely predicted while the width thrown and furrow iv center height were under-predicted. However, the profile results were able to be improved by using smaller particle sizes. In order to model the cohesion and adhesion a linear model, which considers cohesion energy density and contact area of the particles, was integrated into the hysteretic spring contact model. To validate the integrated model, a direct shear test was simulated using three different levels of cohesion. Afterwards, Fielke (1988)'s experimental study performed using a 400 mm width, 10° rake angle, 70° sweep angle, 32 mm lift height and 3 mm high vertical cutting edge sweep tool, at different levels of adhesion, cohesion, speed, operation depth and compaction (soil density) were simulated. A good correlation was obtained between the predicted and measured data of force (R2=0.91 for draft and R2=0.89 for vertical forces). The interaction between the soil and varying tool leading edge geometries was investigated by performing a series of field and glass sided bin tests by Fielke (1994). Finite Element Modelling (FEM) simulations of the glass sided bin tests were also carried out by Fielke (1999). In order to (1) show the possibility of using DEM for simulating soil and varying cutting geometries, and (2) compare the DEM results with FEM results of Fielke (1994)'s experimental study, the DEM simulations and test results were compared to Fielke (1999)'s FEM results. The comparison showed that the draft forces can be accurately predicted using both FEM and DEM (R2=0.86) while more accurate vertical force predictions can be obtained using DEM than with FEM. Overall, the results of the study showed that (1) DEM can be effectively used to model the soil-tool interaction for force prediction and soil movement when an appropriate contact model and parameters are used, (2) to determine the DEM parameters the proposed method which includes an angle of repose and a penetration test can be employed, and (3) the v determined DEM parameters for a cohesionless sand can also be used without any further calibration for a cohesive sandy loam soil when the adhesion/cohesion forces are added to the normal direction in the hysteretic spring contact model. Although the current work was focused on the interaction between the soil and sweep tool, the determined DEM parameters should also be used to simulate the other types of tillage tools
Özet (Çeviri)
Özet çevirisi mevcut değil.
Benzer Tezler
- Kuyu içi (VSP) sismik verilerinin konvansiyonel olmayan yöntemlerle kömür aramacılığına yönelik entegre analizi
Integrated analysis of wellbore seismic data by unconventional methods for coal exploration
ALİ CANKURTARANLAR
Doktora
Türkçe
2024
Jeofizik Mühendisliğiİstanbul Teknik ÜniversitesiJeofizik Mühendisliği Ana Bilim Dalı
PROF. DR. MUSTAFA EMİN DEMİRBAĞ
- Köpükle ötelemenin eclipse ile nümerik simülasyonu
Başlık çevirisi yok
ABBAS AYTAÇ İNAN
Yüksek Lisans
Türkçe
1997
Petrol ve Doğal Gaz Mühendisliğiİstanbul Teknik ÜniversitesiPetrol ve Doğal Gaz Mühendisliği Ana Bilim Dalı
DOÇ. DR. KAMİL HAKAN ALKAN
- Lorentz force effect on turbulent wall-bounded flows
Türbülanslı duvar-sınırlı akışlarda Lorentz kuvveti̇ etki̇si̇
ATİLLA ALTINTAŞ
Doktora
İngilizce
2014
Uçak Mühendisliğiİstanbul Teknik ÜniversitesiUçak ve Uzay Mühendisliği Ana Bilim Dalı
PROF. DR. İBRAHİM ÖZKOL
- An investigation of system identifiation with eccentric mass shakers
Egzantrik kütleli sarsma cihazları kullanarak sistem çözümleme deneylerinin incelenmesi
UMUT KARACADAĞLI
Yüksek Lisans
İngilizce
2010
İnşaat MühendisliğiBoğaziçi Üniversitesiİnşaat Mühendisliği Ana Bilim Dalı
DOÇ. DR. HİLMİ LUŞ
- Filament beslemeli 3 boyutlu yazıcılarda imalat parametrelerinin optimizasyonu
Optimization of manufacturing parameters in FDM 3D printers
ONUR HIRA
Yüksek Lisans
Türkçe
2019
Makine Mühendisliğiİstanbul Teknik ÜniversitesiMakine Mühendisliği Ana Bilim Dalı
DR. ÖĞR. ÜYESİ ATAKAN ALTINKAYNAK