Geri Dön

Simulation of sweep tillage using discrete element modelling

Başlık çevirisi mevcut değil.

PDF İndir

  1. Tez No: 653084
  2. Yazar: MUSTAFA ÜÇGÜL
  3. Danışmanlar: PROF. DR. DANIŞMAN YOK
  4. Tez Türü: Doktora
  5. Konular: Mühendislik Bilimleri, Engineering Sciences
  6. Anahtar Kelimeler: Belirtilmemiş.
  7. Yıl: 2014
  8. Dil: İngilizce
  9. Üniversite: Unıversıty Of South Australıa
  10. Enstitü: Yurtdışı Enstitü
  11. Ana Bilim Dalı: Belirtilmemiş.
  12. Bilim Dalı: Belirtilmemiş.
  13. Sayfa Sayısı: Belirtilmemiş.

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

  1. Tez No

    748680

    Elit kürekçilerde tek ve çift kürek branşlarına göre kuvvet değerlendirmesi

    Strength evaluation of elite rowers according to sculling and sweep OARS rowing branches

    FATİH SANİ

    Doktora

    Türkçe

    Türkçe

    2022

    SporMarmara Üniversitesi

    Beden Eğitimi ve Spor Ana Bilim Dalı

    PROF. DR. NUSRET RAMAZANOĞLU

  2. Tez No

    474963

    Random walk particle modelling of polymer injection using MATLAB reservoir simulation toolbox

    MATLAB rezervuar simülasyon eklentisi kullanarak rastlantısal parçacık hareket metodu ile polimer enjeksiyonu modellemesi

    GÖKHAN MAMAK

    Yüksek Lisans

    İngilizce

    İngilizce

    2017

    Petrol ve Doğal Gaz MühendisliğiOrta Doğu Teknik Üniversitesi

    Petrol ve Doğal Gaz Mühendisliği Ana Bilim Dalı

    YRD. DOÇ. DR. İSMAİL DURGUT

  3. Tez No

    515758

    Sıcak süpürme gazı ile oksijenlendirmenin oksijenatör performansına etkileri

    Effects of warm sweep gas oxygenation on oxygenator performance

    LEYLA KAYA

    Yüksek Lisans

    Türkçe

    Türkçe

    2018

    Göğüs Kalp ve Damar CerrahisiÇanakkale Onsekiz Mart Üniversitesi

    Kalp ve Damar Cerrahisi Ana Bilim Dalı

    DOÇ. DR. TOLGA KURT

  4. Tez No

    634342

    Design of x-bandpass waveguide chebyshev filter based on csrr metamaterial for telecommunication systems

    Telekomünikasyon sistemleri için metamalzeme x-band geçiren filtre csrr tasarımı

    MAHMOUD ABUHUSSAIN

    Doktora

    İngilizce

    İngilizce

    2020

    Elektrik ve Elektronik MühendisliğiGaziantep Üniversitesi

    Elektrik-Elektronik Mühendisliği Ana Bilim Dalı

    PROF. DR. UĞUR CEM HASAR

  5. Tez No

    129329

    Rule-based control for an autonomous vacuum cleaner

    Zemin temizleme robotu için kural tabanlı yöngüdüm yöntemi

    ERKAN ÖZKAN

    Yüksek Lisans

    İngilizce

    İngilizce

    2002

    Bilgisayar Mühendisliği Bilimleri-Bilgisayar ve KontrolBoğaziçi Üniversitesi

    Sistem ve Kontrol Mühendisliği Ana Bilim Dalı

    PROF. DR. YORGO İSTEFANOPULOS

Geri Dön