Granüler Malzemelerin Direkt Kayma Tepkisi Üzerindeki Parçacık Şekli ve Boyut Özelliklerinin Etkilerinin Çok Ölçekli DEM İncelemesi

Öz

Bu çalışma, granüler malzemelerin kayma davranışı üzerindeki tanecik şekli, boyutu ve boyut dağılımı etkilerini Ayrık Elemanlar Yöntemi (Discrete Element Method, DEM) tabanlı çok ölçekli bir yaklaşımla incelemektedir. İlk olarak, literatürdeki doğrudan kesme deneyi verileriyle doğrulanan bir DEM modeli geliştirilmiş, ardından sistematik biçimde farklı tanecik özelliklerine sahip yedi model analiz edilmiştir. Tanecik şeklinin etkisini belirlemek amacıyla, eş hacimli ancak farklı küresellik ve yuvarlaklık değerlerine sahip taneciklerden oluşan modeller oluşturulmuştur. Tanecik boyutu ve boyut dağılımının etkilerini değerlendirmek için farklı çaplara ve gradasyon katsayılarına (Cᵤ) sahip modeller analiz edilmiştir. Sonuçlar, tanecik şeklinin granüler sistemlerin hem makro hem mikro ölçekli davranışı üzerinde en belirleyici parametre olduğunu göstermiştir. Azalan küresellik ve yuvarlaklık, tepe dayanımını artırırken kesme sürecinde temas ağının daha hızlı çözülmesine yol açmıştır. Tanecik boyutu dayanımı ikinci derecede etkilemiş, bu etki çap azaldıkça artmış ancak belirli bir eşik değerin altında azalmıştır. Boyut dağılımı sınırlı bir etki göstermiş, tekdüzelik azaldıkça dilatansın hafifçe arttığı gözlenmiştir. Elde edilen bulgular, tanecik şeklinin granüler sistemlerin dayanım ve deformasyon mekanizmalarını belirleyen temel unsur olduğunu ortaya koymuştur.

Anahtar Kelimeler

• Ayrık Elemanlar Yöntemi (DEM)
• Granüler Malzemeler
• Tanecik Şekli
• Tanecik Boyutu
• Tanecik Boyut Dağılımı

Multi-scale DEM Investigation of the Effects of Particle Shape and Size Characteristics on the Direct Shear Response of Granular Materials

Abstract

This study investigates the impact of particle shape, size, and size distribution on the shear behavior of granular materials using a multiscale Discrete Element Method (DEM) approach. A DEM model validated against direct shear test data from the literature was first developed, and seven models with systematically varied particle properties were analyzed. To assess the influence of particle shape, models with equal-volume particles but different sphericity and roundness were used. The effects of particle size and size distribution were investigated through models containing particles of various diameters and gradation coefficients (Cᵤ). The results demonstrated that particle shape exerts the most significant influence on both macro- and microscale behavior. Decreasing sphericity and roundness increased peak shear strength but led to a faster breakdown of contact networks during shearing. Particle size was the second most influential parameter; its effect intensified as size decreased but diminished below a threshold diameter. Particle size distribution showed a minor effect, with a slight increase in dilatancy observed as uniformity decreased. Correlating macroscale stress–strain responses with microscale coordination number changes confirmed that particle shape is the dominant factor controlling the strength and deformation mechanisms of granular systems.

Keywords

• Discrete Element Method (DEM)
• Granular Materials
• Particle Shape
• Particle Size
• Particle Size Distribution

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