基于土壤胞元非线性运移的振动深松减阻机理研究

Soil deep loosening tillage could break soil hardpan, improve soil property, promote plant roots growth, enhance plant anti-lodge ability and increase yield, so it is one of the most important key technologies for the major needs of food safety. It is acknowledged that the general sub soilers have a problem of big resistance and large power tractors are needed, which affects its promotion and application. In order to optimize the structure of sub soilers and reduce resistance, it is necessary and essential to perfect the accurate mechanical model in the subsoiling tillage process, and further exploring the interactive relationship between soil and sub soilers. Based on the mechanism between the soil and machinery, the purpose of this study is to analyze and research the reduce-resistance mechanism in the vibrating and subsoiling process, construct a accurate model concerning the complex soil surface including articles such as soil, air film and the metal shovel surface, conduct a systematic nonlinear contact constitutive dynamics analysis on the soil-shovel, using base cell methods, investigate the characteristics of soil dissipative particle dynamics, explore the multi-physics vibration function between the soil base cell and shovel surface, finally carry out further research of the resistance reduction mechanism. This study is a combination of mechanical vibration, soil dynamics, numerical analysis and complex interface lubrication technology. Theoretical analysis, combining with indoor soil bin tests and field experiments, will provide a theoretical basis for the development of advanced energy-saying technology and sub soilers.

深松耕作可打破犁底层，有效改良土壤结构，促进作物根系发育、增强其抗倒伏能力、提高单产水平，是面向国计民生粮食安全重大需求的关键技术。一般深松机具普遍存在牵引阻力偏大的问题，影响其推广应用。本项目建立深松耕作过程中精确力学模型，探索土壤-机具之间的相互作用机理、优化设计机具结构、降低牵引阻力。本项目基于土壤-机器互作机理，分析研究振动深松土壤运移减阻机理，构建包括土壤、空气膜和入土铲表面的复杂介质中土壤团粒精确运移模型；利用空隙胞元法对土壤-铲面作用系统进行非线性接触本构动力学分析，研究土壤团粒耗散粒子动力学特性，探索振动深松的壤块胞元与铲面间的多物理场耦合作用，进而研究振动深松的减阻机理。本研究融合了机械振动学、土壤动力学、数值分析和复杂界面建模技术，将理论分析、土槽试验和田间测试验证相结合，研究成果将为研发新型减阻节能深松机具提供理论依据，为土壤改良提供先进技术装备支撑。

针对深松牵引阻力大、耗能高等问题，本项目基于土壤胞元非线性运移原理，结合振动力学理论，通过开展深松阻力与振动方式、深松深度、耕作速度等评价指标的相关性研究，确定了影响深松阻力的振动深松机的各项物理参数，建立了相应的数学模型。对振动深松减阻机理进行研究，其具体研究内容主要包括：.1、振动深松机的研制.针对深松作业阻力大，基于振动减阻原理，探索土壤和机具之间的相互作用机理，以降低牵引阻力为目的。通过理论分析研究振动深松减阻的机理，建立“深松铲-土体”模型，研制振动深松样机，通过试验得出影响深松阻力的主要因素有振动频率、振幅、振动角、前进速度和深松铲铲形等。各项试验数据表明：振动深松较不振动平均减阻19.28%，减阻效果良好。.2、自激式振动深松机的研制. 基于自激减阻原理，设计自激式振动深松机。应用离散元法对 “土壤-深松铲”模型进行研究，通过理论与试验相结合，得出影响自激振动深松阻力的主要因素有弹簧型号、耕速、耕深等。试验数据表明：不同弹簧型号、不同耕速，不同耕深较非振动平均减阻47.79%，减阻效果明显。.3、基于离散元法研究深松减阻效果.基于离散元法，建立以不同直径球形土壤颗粒组合为基本单元的土壤颗粒模型区分表层与犁底层颗粒，并建立了土壤与深松铲接触模型，通过土壤筛分试验和直剪试验测定EDEM仿真下土壤参数，并分析不同耕速、耕深下深松铲所受牵引阻力规律，结果表明，随着耕速和耕深的增加，自激振动深松机所受牵引阻力增加。.通过该项目的实施，为振动深松领域奠定了理论基础，同时为不同振动方式的减阻机理提供了技术支持。项目发表专著1部，论文5篇，申请专利8项（发明专利授权2项），培养研究生5名。