南湖新聞網訊（通訊員 劉婉茹）近日，我校yl7703永利水稻與水生蔬菜機械化生産技術與裝備團隊張國忠教授課題組研究成果以“Microscopic Deformation and Fragmentation Energy Consumption Characteristics of Soils with Various Moisture Contents Using Discrete Element Method”為題在土壤科學和耕作研究領域期刊Soil & Tillage Research發表。

該研究建立了5種不同含水率土壤的離散元模型，分析獲取了土壤在軸向載荷作用下的應力應變特征與能量耗散規律，闡明了土壤微觀形變與破碎能耗之間的影響機理。該成果可為地面機器系統研究領域中黏塑性土壤條件下耕播管收等裝備的行走、開溝、碎土等各類觸土工作部件的節能降耗設計提供重要理論指導。

節能降耗是地面機器系統領域研究的重要課題，尤其在南方黏重土壤條件下，土壤濕粘會使耕整和收獲部件阻力增加30%以上，能耗增加30～50%，土壤變形破碎是内部能量演化并與外界進行能量傳遞的過程，應力應變規律和能量耗散機制是研究土壤破碎的核心内容，但目前濕粘土壤的微觀形變以及其與破碎能耗間的關聯影響機制不明确。為此，針對這一重要共性基礎問題，張國忠教授團隊建立并标定了5種不同含水率土壤的離散元模型，通過引入裂隙率和裂隙傳遞系數，從微觀層面定量闡述了土壤失穩破碎的根本原因，明晰了不同含水率土壤在軸向載荷下的微觀形變與破碎特征，從而為地面機器系統節能降耗研究提供了新思路和新方法。

基于Bonding和JKR耦合接觸構建的土壤離散元模型

實際與仿真土壤試樣微觀形變與破碎特征

yl7703永利在讀博士研究生劉婉茹為論文第一作者，張國忠教授為通訊作者。本研究得到國家自然科學基金、國家特色蔬菜産業技術體系、湖北省優秀中青年創新團隊等項目資助。

審核人 張國忠

【英文摘要】

Increased soil moisture content commonly leads to higher resistance and energy consumption during agricultural operations. However, the impact of moisture content on soil microscopic deformation and fragmentation energy consumption characteristics remains unclear. In this study, discrete element models of sandy clay loam with different gravimetric water contents (15.0%, 18.8%, 21.6%, 24.1%, and 27.3%) were constructed for simulation experiments using coupled contact method (Hertz-Mindlin with bonding and Hertz-Mindlin with JKR). The degree of soil fragmentation and the rate of crack propagation were investigated. The results indicated that at fixed gravimetric water content, fissure rate exhibited a pattern of slow increase, rapid increase, and eventual stabilization with increasing compression displacement, while the fissure transfer coefficient showed a pattern of first increase and then decrease. At a fixed compression displacement, the increase in moisture content led to a decrease in both fissure rate and fissure transfer coefficient. The analysis of soil stress-strain characteristics and energy dissipation patterns found that soil with a gravimetric water content of 27.3% (close to soil liquid limit) exhibited no compression yield point; at a soil gravimetric water content of 15.0%, the minimum crushing energy (Udmin) was achieved (1.32 J), with a maximum elastic strain energy (Uemax) of 1.83 J. Similarly, at a soil gravimetric water content of 24.1%, the minimum crushing energy (Udmin) was reached (2.17 J), with a maximum elastic strain energy (Uemax) of 2.25 J. The comparison between actual and simulated results revealed low relative errors (<6%) in Udmin for all the above soil gravimetric water contents, suggesting the feasibility of our coupled discrete element model for assessing soil crushing energy consumption. This study revealed microscopic deformation and instability fragmentation mechanisms of soils with various moisture contents under vertical axial loads. Our findings provide novel method and strategy for developing the high-efficiency low-consumption soil fragmentation model.

來源：南湖新聞網http://news.hzau.edu.cn/2024/0423/69516.shtml