本研究的目的在探討不同顆粒形狀的ABS顆粒體及AISI 1012碳鋼顆粒體在壓克力圓柱容器中受到束制壓力負載的力學行為。實驗中採用的ABS顆粒體包括: 球形、橢圓Ⅰ形、橢圓Ⅱ形、膠囊形、雙球形，此外，實驗中採用的碳鋼顆粒體包括：球形、飛碟形、圓柱形、漢堡形。利用不同形狀的顆粒體進行實驗得到的應變、頂部壓板的位移、負載、底部力，計算出容器壁上三個不同高度位置的力學性質，其中包括：正向壁面壓力、沿著壁面的垂直剪應力、平均垂直應力、側向壓力比、體壁摩擦啟動係數。透過比較不同顆粒形狀的顆粒體的實驗結果以探討顆粒形狀對顆粒體力學行為的影響，此外，建置離散元素電腦模擬，分析三種不同摩擦係數的AISI 1012碳鋼球形顆粒體，並比較其實驗結果。 實驗數據顯示，顆粒邊壁間摩擦係數增加導致邊壁的摩擦效應增加，造成碳鋼顆粒體的負載傳遞效率下降，此外，在不同負載情況下，正向壁面壓力、沿著壁面的垂直剪應力、平均垂直應力均沿顆粒體深度而減少，皆隨負載上升而增加。由不同形狀的ABS顆粒體及碳鋼顆粒體的實驗結果得知，顆粒體的勁度隨負載上升而增加，然而，孔隙率較大的顆粒體，其勁度增加率較小，這是由於較多的空隙增加顆粒重新排列的機率，導致負載下降的情況增加。顆粒形狀對ABS顆粒體的側向壓力比的影響較不明確，但側向壓力比隨深度增加而減少。比較四種形狀的碳鋼顆粒體的側向壓力比，得知球形及飛碟形顆粒體的側向壓力比圓柱形及漢堡形顆粒體的側向壓力比大，這意味著球形及飛碟形的粒體較其他兩種形狀的顆粒體容易側向擠壓容器壁。由ABS顆粒體的體壁摩擦啟動係數的實驗結果得知，體壁摩擦啟動係數越趨近顆粒邊壁間摩擦係數，顆粒體與容器壁接觸越傾向於發生滑動摩擦。 ;The purpose of this study is to investigate the mechanical behavior of granular materials under confined compression in an acrylic cylinder. The granular materials used in experiments include ABS particles with five kinds of particle shape (spherical, ellipsoidal I, ellipsoidal II, capsule and paired particle) and AISI 1012 steel particles with four kinds of particle shape (spherical, satellite, cylindrical and hamburg particle). In addition, the discrete element method (DEM) is used to model the mechanical behavior of AISI 1012 steel spherical particles with three kinds of friction coefficients under confined compression. The comparison between the DEM simulation and the corresponding experiment is made and discussed. The study shows that an increase of the particle-wall friction coefficient leads to a decrease in the load transfer efficiency. The normal wall pressure, vertical shear wall traction and average vertical stress decrease with depth of granular assembly and increase with increase of top load. The loading stiffness increases with load. However, a granular assembly with a greater initial porosity leads to a smaller loading stiffness. Particle shape on the lateral pressure ratio of ABS particles has no noticeable effect. However, the lateral pressure ratios of spherical particles and satellite particles are larger than those of cylindrical particles and hamburg particles.
