As an important part of national natural resources, forest has important research value. The construction of virtual forest realistic model has economic and social benefits such as film and television special effects, game entertainment and forest ecology, and is conducive to the accumulation and arrangement of world digital forest resources. At present, different virtual forest modeling methods still have some deficiencies in expressing the reality of the model. Based on the analysis of the research status of virtual forest, this paper gives different classifications of realistic modeling methods, and summarizes the theoretical basis, application fields, advantages and disadvantages of reconstruction methods based on real world data, interactive modeling methods and system modeling methods based on rules or procedures. In addition, the most popular modeling software with strong applicability is summarized and compared. Finally, the existing problems and further development trend of realistic forest modeling methods are discussed.

我国是农业大国,秸秆资源非常丰富,利用好秸秆资源可极大地解决动物饲料紧缺问题,同时也极大地解决焚烧秸秆带来的环境问题.本文在分析秸秆膨化机工作机理的基础上,对秸秆膨化机中的关键部件螺杆及腔体进行结构设计.为解决膨化机输料堵塞问题,在不更换电机的条件下,通过ANSYS Workbench的流体模块,对螺杆外腔体的速度流场、涡流黏度流场和工作压力流场等进行有限元流场分析,对比得出螺杆与套筒间隙最佳区域.根据标定的生产目标进行试验验证,当螺杆与套筒间隙为5 mm时,秸秆膨化机的结构能达到预期的生产效率,秸秆膨化质量良好.本文研究的秸秆膨化机改变了秸秆的适口性,将适口性差的农作物秸秆变为适口的饲料.

气力式小粒种子精密排种器是蔬菜种植产业实现机械化的关键作业工具,该播种器的使用可以大大提高播种精度及效率,保证出种率,实现精密播种,便于作物的后期管理以及收获,不仅可以节省种子,减少人工劳动成本,而且能够提高作物产量.使用JPS-12型排种器试验台对小粒种子排种器进行台架试验,通过单因素试验,明确了排种器转速、气室负压、种堆端面高度3个排种器运行参数对排种器性能的影响规律;通过正交试验,探究排种器转速、气室负压、种堆端面高度同时改变时,对小粒种子排种器播种合格率、漏播率、重播率影响的主次顺序,并获得最优参数组合.为排种器工作时选择最优运行参数及探究不同运行参数对排种器播种质量的影响规律提供相关数据支撑,为小粒种子排种器的设计与制造提供理论依据.

为使水稻覆膜直播机的机架满足覆膜直播工作的承载要求,避免机架变形过大影响覆膜平整度,同时为避免机架与发动机等激振源发生共振现象,利用ANSYS软件对水稻覆膜直播机机架进行静力学分析以及模态分析.通过对3种材质的机架进行静力学分析,根据分析结果进行综合评估,材质Q235的机架为最优.在对Q235机架进行模态分析中,获得机架的前六阶固有频率.将主要激振源的激振频率与机架的前六阶固有频率进行比较,其结果说明机架工作中不会发生共振现象.最后通过田间试验验证所设计机架能满足覆膜直播作业的要求.