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基于DEM-MBD耦合算法的自激振动深松机仿真分析 总被引:2,自引:0,他引:2
自激振动深松机的设计主要采用田间试验及理论分析方法,但田间试验成本高、周期长,同时理论分析尚不具备完整准确的解析解。为提高该类机具的设计效率,保证设计结果的准确性和可靠性,本文在课题组研制的Agri-DEM软件平台上,添加了离散元法(DEM)与多体动力学(MBD)耦合算法,然后利用该算法对自激振动深松单体作业过程进行仿真分析。耦合算法中,采用MBD方法建立了台车-深松机-悬挂架-土壤的系统动力学模型,包括7个活动刚体、1个滑移铰、7个转动铰、1个滑移驱动、1个弹簧力约束和1个阻尼约束,同时利用广义坐标分块算法将系统微分代数方程组转化为微分方程组,并通过亚当斯-莫尔顿校正算法进行积分,求解获得各刚体的运动学参数和动力学参数;采用DEM方法建立了耕作土壤的离散元模型,考虑土壤颗粒的黏附力,提出一种适合于土壤等湿颗粒间的接触力学模型——湿颗粒模型,模型参数通过试凑法确定。对模型进行深松铲的动力学响应分析、弹簧及牵引力动力学响应分析和土壤扰动过程分析,仿真结果表明:土槽台车前进速度为0.5m/s时,机具牵引力周期性变化的区间为-331.06~1492.75N,最大牵引力为1492.75N;深松铲的入土角周期性变化的区间为0~-0.11rad,在高度方向上铲柄质心的变化区间为-400.33~-581.37mm;激振弹簧受载也呈周期性变化,变化区间为2623~-2231N;深松铲铲尖部位抬升土壤,土壤颗粒扰动量在铲尖区域最大,并沿深松铲前进方向和侧向依次递减。仿真结果直观的呈现了自激振动深松机的作业过程及土壤颗粒的运动情况,定性的解释了自激振动深松机的减阻机理。本文添加的DEM-MBD耦合算法,为自激振动深松机工作过程分析和优化设计提供了一种新方法。 相似文献
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Comparison of various coulter‐type ground‐driven rotary subsoilers in terms of energy consumption and soil disruption 下载免费PDF全文
Hardpans below the normal tillage depth inhibit root penetration and cause drainage problems. Subsoiling is commonly used to disrupt hardpans and provide pathways for water and roots to enter the subsoil. The objective of this study was to develop and compare various types of ground‐driven rotary subsoilers that adequately disrupt compacted soil profiles for conservation tillage systems. To accomplish these objectives, four different coulter‐type ground‐driven rotary subsoilers were designed and manufactured by dividing a 1.2 m diameter coulter into multiple blades. Minimizing the soil resistance was one of the main considerations in forming the shape and number of blades on the coulters. An experiment was conducted in a soil bin to determine the effects of ground‐driven rotary subsoilers on soil disturbance and energy requirements. Treatments were four different types of subsoilers: coulter without blade (CNB), coulter with 5 blades (C5B), coulter with 7 blades (C7B) and coulter with 9 blades (C9B), and two tillage depths (25 cm and 38 cm). To determine the differences between subsoilers, soil disturbance, cone index, bulk density and draft were measured. The C5B subsoiler required considerably less draft, draft power and vertical force for both operation depths followed by the C7B, C9B and CNB subsoilers. The CNB subsoiler left the soil surface clean with no spoil while the coulters with blades caused spoils on the soil surface. The soil disruption paths of the coulters with blades have an advantage for row crops due to limited above‐ground disturbance if seeds can be placed in the middle of the disrupted zone. 相似文献
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设计并研制了小型深松机,在收获后秸秆还田的基础上进行了深松试验。结果表明,深松可以显著地减小地表不平度,播种质量有显著提高,对于促进保护性耕作技术发展具有积极的作用。通过深松使土壤容重下降,增大了土壤渗水率和含水量,对春天干旱区域来说有利于吸纳雨雪并缓解干旱。 相似文献
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农村现有的拖拉机基本上都是中小功率的,与作业阻力较大的全方位深松机不相匹配。为此,设计了一种与中小功率拖拉机相配套的深松整地机。详细阐述深松机关键部件深松铲的刀头和翼铲受力情况和设计思路,分析计算深松机牵引阻力,旨在为机具的推广应用提供参考。 相似文献
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深松是实施保护性耕作、获取农作物高产必不可少的机械化作业项目。研究表明,深松机的深松部件——深松铲的形状和结构参数对土壤深松质量及作业效果有很大的影响。对比凿型深松铲、箭型深松铲和双翼深松铲深松后的效果,结果表明:在相同条件下,凿型深松铲在打破犁底层后改善土壤持水量、土壤温度和土壤坚实度方面的综合作用效果好。 相似文献