【作者】 危夏；

【导师】 付宏；

【作者基本信息】 吉林大学 ， 软件工程， 2004， 硕士

【摘要】 在工程设计过程中，经常要利用计算机作为工具，帮助设计人员进行产品设计。计算机辅助设计的应用，大大提高了企业的产品开发能力，但目前设计人员所采用的AutoCAD软件是相对于通用性图纸设计的，而对某些有特别要求专业性图纸设计，还不能完全满足要求。本文着手对计算机辅助设计软件（AutoCAD）进行二次开发，并使之与同时开发的离散元仿真分析软件集成，从而开发出一种适用于播种机精密排种器的分析设计软件，该软件能够对于设计阶段的机械零部件模型进行工作过程仿真，以帮助设计人员分析设计参数，修改设计草图，这样将设计产品制作成实际工作部件时候，能够减少试验次数，提高设计效率。该软件由前处理模块和后处理模块组成，前处理模块用于根据农机工作部件的CAD模型生成其离散元法分析模型,并且向后处理模块进行数据传递。后处理模块接收前处理模块传递的数据参数，生成相应的数字化模型，并依据离散元计算散粒体的运动速度和位移，最后实现散粒体运动的动态仿真，为设计人员提供分析参考数据。前处理模块选择用AutoCAD二次开发工具ObjectARX 2000进行开发，将精密排种器的CAD模型成所需要的离散元法分析模型,具体实现步骤是将CAD模型中的基本图形元素提取出来，去除冗余部分，同时添加上特定的属性（如运动方式等），最后将其保存到数据库中。后处理模块开发中，主要依据二维离散元法。开发平台是Windows 2000,开<WP=50>发工具为VC++ 6.0。此模块依据离散元法的力学模型，通过迭代算法计算出每一时步散粒体的受力情况以及位移，每隔一段时间将计算结果保存在文件中。当计算完成后，利用VC++ 6.0的TIME控件实现运动过程仿真，由此可以观察散粒体运动情况，以及散粒体与农机工作部件的相互作用情况，为农机工作部件的设计提供分析依据。通过使用该软件分析一种新型精密排种器内种子的运动状况，并与实际该排种器工作时种子的运动情况比较可知，所开发软件可用于精密排种器的性能分析和设计。更多还原

【Abstract】 In the course of engeneering design,computer as a aid tool is oftern used to help the designer to design product.The application of CAD have greatly improved the ablity of enterprise’s development.But most softeware of CAD is for the genneral design.There is no help when they meet some profession design.This paper firstly presented re_development of AutoCAD and develop a pre_modual to deal with the drawing file. Integrated with the pre_modual,we develope an emluator and analysis software.Then .We can get a design system which can emluator work of engine components to help the designer analyse the design parameter and modify sketch map.Then when the design was made be real componnents,it can reduce the times of experiments and improve the design efficiency.This system mainly consists on before-treatment dealing sub-system, after-treatment dealing sub-system.The after-treatment dealing sub-sub system is splitter two modual.One modual is for DEM calculating;The other modual is deal with the emluator and analysis. It uses Visual C++6.0, ObjectARX and AutoCAD as the development tools. In order to be more convenient to expand the systematic function further, every sub-system is developed based on orient-object method. Among them dealing sub-system and DEM calculating sub-system relied on the database to transmit the data, and DEM calculating sub-system and after-treatment sub-system’s integrating are realized by writing and reading the same datum file.The before-treatment dealing sub-system is a re-development utilizing ObjectARX2000 to carry on under the environment of AutoCAD2000. The main purpose is to distill the drawing which the designer designed with AutoCAD, and sets up the movement way in the course of calculating in emulation of every figure element (such as a line segment, a section of arcs), set up the emulation models of " the element of the figure plus movement way ", and store the model in the database, support DEM calculating that sub-system is used.The DEM calculating modual calculates receiving- strength situation and sport situation of agricultural machinery part with agricultural particle materiel, particle materiel with particle materiel. Users can choose the analysis model which is wanted to calculate in the figure database, and then according to the characteristic of supplies choose different mechanics model and input the relevant parameter, utilize DEM <WP=53>algorithm to calculate out dispersed sport orbit, receiving-strength situation, and write down the information in the form of files. This sub-system adopts multiply document, multiply thread technology, can not merely calculate a lot of analysis models at the same time, but also provide stop calculating, continue calculating function, make users can watch the result of emulation ahead of time, but needn’t finish calculating after all.The after-treatment dealing modual shows the dynamic emulation data in the form of figure while the DEM calculating finishes or after, and offer the function of quickly putting, slowly putting, suspending, stopping etc.The research of this text has heavy meaning for improving the accurate research and design level of precision maize seed metering device, reducing test links and experimental times, reducing unnecessary loss in working course and improving performance.更多还原