{"created":"2022-01-27T02:36:29.204037+00:00","id":2002713,"links":{},"metadata":{"_buckets":{"deposit":"9bc7afc1-f369-4d1f-9d7c-4cd5db86dd9c"},"_deposit":{"id":"2002713","owners":[1],"pid":{"revision_id":0,"type":"depid","value":"2002713"},"status":"published"},"_oai":{"id":"oai:u-ryukyu.repo.nii.ac.jp:02002713","sets":["1642837622505:1642837905044:1642837920612","1642838403551:1642838407312"]},"author_link":[],"item_1617186331708":{"attribute_name":"Title","attribute_value_mlt":[{"subitem_1551255647225":"農用車両の走行性に関する基礎研究","subitem_1551255648112":"ja"},{"subitem_1551255647225":"Traveling Performance of Farm Vehicles","subitem_1551255648112":"en"}]},"item_1617186419668":{"attribute_name":"Creator","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"鹿内, 健志","creatorNameLang":"ja"}]},{"creatorNames":[{"creatorName":"Shikanai, Takeshi","creatorNameLang":"en"}]}]},"item_1617186476635":{"attribute_name":"Access Rights","attribute_value_mlt":[{"subitem_1522299639480":"open access","subitem_1600958577026":"http://purl.org/coar/access_right/c_abf2"}]},"item_1617186609386":{"attribute_name":"Subject","attribute_value_mlt":[{"subitem_1522299896455":"ja","subitem_1522300014469":"Other","subitem_1523261968819":"車輪"},{"subitem_1522299896455":"ja","subitem_1522300014469":"Other","subitem_1523261968819":"土壌変形"},{"subitem_1522299896455":"ja","subitem_1522300014469":"Other","subitem_1523261968819":"けん引力の変動"},{"subitem_1522299896455":"ja","subitem_1522300014469":"Other","subitem_1523261968819":"支持力"},{"subitem_1522299896455":"ja","subitem_1522300014469":"Other","subitem_1523261968819":"すべり線場"},{"subitem_1522299896455":"en","subitem_1522300014469":"Other","subitem_1523261968819":"wheel"},{"subitem_1522299896455":"en","subitem_1522300014469":"Other","subitem_1523261968819":"soil deformation"},{"subitem_1522299896455":"en","subitem_1522300014469":"Other","subitem_1523261968819":"oscillation of drawbar pull"},{"subitem_1522299896455":"en","subitem_1522300014469":"Other","subitem_1523261968819":"bearing capacity"},{"subitem_1522299896455":"en","subitem_1522300014469":"Other","subitem_1523261968819":"slip-line field"}]},"item_1617186626617":{"attribute_name":"Description","attribute_value_mlt":[{"subitem_description":"本論文は軟弱地盤において作業を行なう農用車両の走行性に関して, 車輪と土の力学的相互作用の面から究明し, さらに, 耕盤を有する圃場の車両に対する支持力特性について解明し, 農用車両走行部の力学的設計に不可欠な基礎的知見を提示したものである。まず, 車輪と土の力学的作用を把握するため走行車輪下の土の変形計測システムの開発を行なった。本システムにより気乾豊浦標準砂を対象に車輪走行実験を行い, 走行車輪下の土の変形およびけん引力, 接地応力など走行性に関する力学的諸量の計測を行なった。また, 車両の支持力特性について, すべり線法による理論解析を行なった。耕盤を有する圃場の車両に対する支持力問題を, 剛盤上の摩擦性塑性体の二つの近接する荷重に対する支持力問題と理想化した。荷重間隔, 荷重幅および耕盤深さに応じて五つのすべり線場を設定し, これらに基づき支持力の計算を行なった。以下, 各章ごとの総括と結論を述べる。第1章において, 新たに開発した走行車輪下の土の変形計測システムの構造と特徴について論じた。厚さ25μm, 直径5mmのポリエステル製の円形マーカを土槽側壁の内側に設置し, マーカの土に伴う動きを透明な土槽側壁を通し連続写真撮影した。2軸X-Yテーブルと拡大CCDカメラからなる平面位置検出装置により写真からマーカ座標を読取った。これにより土中の変位分布を計測し, さらに有限要素解析における方法を用いて土中ひずみ分布を算定した。計測の不確かさ解析により, 従来の土の変形測定法に比較し, 簡易な方法で, 微小変形から大変形にわたり高精度で計測が可能であることが確認された。また, 新たに開発したマーカは薄いポリエステル製で周辺土壌へ影響を与えることなく, また, 含水比が比較的高い一般の圃場の土に対して使用可能である。第2章では, 土の変形解析システムにより計測した走行車輪下の土の変形解析結果について述べた。車輪は剛性車輪を対象とし, 車輪表面材の摩擦係数による違いを比較するため, 鋼鉄製車輪と鋼鉄製車輪の表面に加硫したクロロプレンゴムを5mm厚さでコーティングしたゴム被覆車輪の2種類を供試した。静的沈下時の土粒子の動きの変位ベクトルは, ゴム被覆車輪および鉄製車輪とも車輪中心を通る鉛直線を中心軸として対称に分布する。車輪が回転すると, 変位ベクトルは車輪前方部で, 前向きの水平成分を持つものと後向きの水平成分を持つものの二つの領域に分けられることがわかった。","subitem_description_type":"Other"},{"subitem_description":"土の経時的な動きを明らかにするため, 深さ毎の土粒子の変位の軌跡を求めた。また, 土粒子の軌跡を指数関数を用いて表現した。土粒子は車輪中心線が真上にくると, 大略, 最大深さまで動く。ゴム被覆車輪下の土粒子の描く曲線は鉄製車輪のものより土中深くまで移動し, 後方への変化も大きい。車輪と土の接触面では土は車輪表面に固着して動くのではなく, 車輪と土との間にすべりが生じる。鉄製車輪では摩擦係数が小さく, 接触面での車輪と土とのすべりが大きくなり土粒子の変位が小さいと考えられる。ゴム被覆車輪および鉄製車輪下の土中ひずみ分布を等値線図により詳細に示した。各すべり率における鉛直方向・水平方向の垂直ひずみおよびせん断ひずみの特徴について述べ, ゴム被覆車輪と鉄製車輪のひずみ分布の比較を行なった。第3章では, ゴム被覆車輪および鉄製車輪の接地面法線・接線応力分布とけん引力の変動現象について述べた。法線および接線応力の分布はいずれの車輪においても車輪前方部で最大値を示す凸型の曲線を描く。また, 法線および接線応力の最大値はすべり率の変化に伴い変化する。すなわち, 最大法線応力はすべり率の増大とともに減少する。最大接線応力はゴム被覆車輪ではすべり率40%付近まですべり率とともに増加し, その後一定値を示すが, 鉄製車輪ではすべり率40%付近で極大値を示す。接線応力の法線応力に対する比(接地応力比)は, ゴム被覆車輪および鉄製車輪とも車輪と土の接触が始まる部分と接触が終わる部分で高い値を示し, 最小値はその間に現れる。最小値が現れる位置はすべり率が大きくなると車輪前方部に移動する。けん引力の経時的な変動現象を究明するため, その波形を車輪回転角を変数とする正弦関数で近似した。ゴム被覆車輪のけん引力の変動はすべり率によらず, 短周期の振幅の小さい微小振動を示し, 鉄製車輪の場合, 長周期で, すべり率が増大するほど振幅の大きくなる波形を示す。ゴム被覆車輪と鉄製車輪のけん引力の変動の周期と振幅について車輪下の土の破壊態様と照応して論じた。第4章では, 耕盤を有する圃場の車両に対する支持力問題について論じた。すなわち, 本支持力問題を, 二つの近接する荷重が剛盤上の摩擦性剛塑性体に作用するものとしすべり線法により解析を行なった。2荷重によるすべり線場が干渉し, 一般にPrandtl場は成立しないが, 荷重幅, 荷重間隔および耕盤深さに応じて5種","subitem_description_type":"Other"},{"subitem_description":"Result of research on the traveling performance of off-road vehicles, e. g. farm and construction machinery, which had been performed in order to indicate the guidelines for mechanical designing these vehicles is described in this article. Especially, the vehicle-soil interaction is studied experimentally and theoretically in detail. First, a measurement system for soil displacement has been developed in order to elucidate the mechanical interaction between a wheel and soil. The traveling performance of rigid wheels and the displacement of soil beneath a wheel has been measured on sand stratum at different slips using the measurement system. Two kinds of rigid wheels, i. e. the steel wheels without a coating and with the coating of vulcanized chloroprene rubber with 5mm thickness, were prepared to compare the effect of friction on the wheel surface. In addition, the bearing capacity of farm land for a vehicle is analyzed by the slip-line method. A vehicle traveling on farm land is idealized as two adjacent loads penetrating into frictional rigidperfectly plastic solid on rigid sole pan. Five types of interfering slipline fields are proposed depending on geometric states of load and farm land. The variation of the bearing capacity is then discussed in relation to the load width, the load interval and the depth of the sole pan. The results and conclusions in each chapter are summarized in the following. In chapter 1,the characteristics and components of the measurement system for soil displacement are described. Markers made of thin polyester film with 5mm diameter and 25μm thickness are set inside of a soil bin wall. Photographs of the markers which moved with soil deformation are taken intermittently over the wheel rotation through the transparent soil bin wall. The position of the markers are read using a detective device composed of a two-axis (X-Y) table and a microscopic CCD camera. The distribution of soil displacement was measured and the soil strain was calculated from the soil displacement by the method used in the finite element analysis. From the uncertainty analysis, it is confidently expected that the system could measure the soil deformation with high accuracy for infinitesimal and large deformations. The marker does not disturb the soil condition because it is made of a thin polyester film, and thus this system would be applicable to general farm soils even with a high moisture content. In chapter 2,the results of soil deformation beneath a traveling wheel are discussed. The displacement vectors spread symmetrically with respect to the vertical line on the wheel center. After the wheel rotation, the distribution of the displacement vectors was divided into two zones, i. e., one with vectors directed forward and the other with vectors directed backward. The trajectories of the soil particles could be approximated by an exponential function. When the center of the wheel came onto the soil particle, the particle reached the almost deepest point on the trajectory. The trajectories for the rubber-coated wheel were larger than those for the steel wheel due to the larger coefficient of friction. The distribution of soil strain was calculated and displayed as contour maps. The difference of the distributions for the rubber-coated and the steel wheel was discussed for normal strain in the vertical and horizontal directions and shear strain. In chapter 3,the distribution of ground contact stresses, such as normal and tangential stresses, and the fluctuation in drawbar pull are examined. The distribution curve of each contact stress showed a peak at the front side of the wheel-soil interface. The maximum value of the normal and tangential stresses varied with slip. The maximum normal stress decreased with an increase of slip for both wheels. The maximum tangential stress increased at nearly 40% slip with an increase of slip, and then showed a constant value for the rubber-coated wheel. For the steel wheel, the peak value o","subitem_description_type":"Other"},{"subitem_description":"紀要論文","subitem_description_type":"Other"}]},"item_1617186643794":{"attribute_name":"Publisher","attribute_value_mlt":[{"subitem_1522300295150":"ja","subitem_1522300316516":"琉球大学農学部"}]},"item_1617186702042":{"attribute_name":"Language","attribute_value_mlt":[{"subitem_1551255818386":"jpn"}]},"item_1617186783814":{"attribute_name":"Identifier","attribute_value_mlt":[{"subitem_identifier_type":"HDL","subitem_identifier_uri":"http://hdl.handle.net/20.500.12000/3684"}]},"item_1617186920753":{"attribute_name":"Source Identifier","attribute_value_mlt":[{"subitem_1522646500366":"ISSN","subitem_1522646572813":"0370-4246"},{"subitem_1522646500366":"NCID","subitem_1522646572813":"AN00250548"}]},"item_1617186941041":{"attribute_name":"Source Title","attribute_value_mlt":[{"subitem_1522650068558":"ja","subitem_1522650091861":"琉球大学農学部学術報告"},{"subitem_1522650068558":"en","subitem_1522650091861":"The Science Bulletin of the Faculty of Agriculture. University of the Ryukyus"}]},"item_1617187056579":{"attribute_name":"Bibliographic Information","attribute_value_mlt":[{"bibliographicIssueNumber":"45","bibliographicPageEnd":"107","bibliographicPageStart":"53"}]},"item_1617258105262":{"attribute_name":"Resource Type","attribute_value_mlt":[{"resourcetype":"departmental bulletin paper","resourceuri":"http://purl.org/coar/resource_type/c_6501"}]},"item_1617265215918":{"attribute_name":"Version Type","attribute_value_mlt":[{"subitem_1522305645492":"VoR","subitem_1600292170262":"http://purl.org/coar/version/c_970fb48d4fbd8a85"}]},"item_1617605131499":{"attribute_name":"File","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_access","filename":"KJ00000161854.pdf","mimetype":"application/pdf","url":{"objectType":"fulltext","url":"https://u-ryukyu.repo.nii.ac.jp/record/2002713/files/KJ00000161854.pdf"},"version_id":"515b8183-ff89-46af-bd51-77e7d04562e0"}]},"item_title":"農用車両の走行性に関する基礎研究","item_type_id":"15","owner":"1","path":["1642837920612","1642838407312"],"pubdate":{"attribute_name":"PubDate","attribute_value":"2008-02-14"},"publish_date":"2008-02-14","publish_status":"0","recid":"2002713","relation_version_is_last":true,"title":["農用車両の走行性に関する基礎研究"],"weko_creator_id":"1","weko_shared_id":-1},"updated":"2022-02-14T21:39:57.431421+00:00"}