【作者】 陈鹏霏；

【导师】 孙志礼；

【作者基本信息】 东北大学 ， 机械设计及理论， 2009， 博士

【摘要】 大型机械产品广泛应用于国民经济的各个部门,它们的可靠性、经济性和安全性是一个国家机械工业发展状况和水平的标志。目前,国内安全生产的形势依然严峻。由于大型设备发生故障,而导致重大经济损失,甚至造成人身伤亡的严重事故,不胜枚举。同时,制造业市场的竞争愈演愈烈,产品的设计、试验、生产及投入市场的周期是相关企业生存和发展的关键。如何迅速、快捷地设计出经济、可靠的机械类产品,始终是工程科技人员全力研究的重点内容。往复式压缩机具有压力范围广、热效率高、适应性强等特点,是化工合成和石油开采等领域必不可少的关键设备。由于其结构庞大、设计周期长、制造费用高昂等原因,导致目前产品在可靠性、经济性和灵活性等方面存在的问题日益突出。而且,此类机械产品大都是小批量,甚至单件生产,难以完成大样本的试验研究;同时,用户的需求多变,需要能够快速地响应市场。因此,对此类机械产品开展可靠性分析、敏捷化设计和虚拟可靠性试验研究的工作具有现实意义。本文以大型往复式压缩机产品为研究对象,将可靠性理论与计算机技术相融合,提出了机械数字化研究的理念,分别从分析、设计和仿真三个方面展开研究;同时,在分析研究的基础上,对压缩机的局部结构进行了改进,通过理论计算和ANSYS仿真分析两种手段,验证了改进后结构的合理性和有效性。论文具体的研究工作如下:(1)开发了往复式压缩机设计计算的程序平台。该平台基于VC++编程语言,结合Matlab软件,将原本复杂繁琐的热力学与动力学计算变得简单、易行,并且能够迅速、准确地获得各项设计数据和各种载荷曲线,为关键零部件的强度校核和设计系统、仿真系统的建立提供基础。(2)开发了关键件可靠性灵敏度分析的程序平台。以经典的强度校核理论为基础,考虑到各种设计参数(尺寸公差、材料属性和加工工艺等)的随机性,建立关键零部件可靠性灵敏度分析的数学模型;以VC++6.0为开发环境,实现分析过程的可视化和程序化。该平台能够以概率的形式定量给出压缩机关键件的可靠性评价指标,给出各种设计参数对可靠度的影响程度,为合理地选择和控制设计参数提供指导。(3)开发了往复式压缩机的参数化设计系统。该系统基于Pro/E软件和Pro/TOOLKIT二次开发工具包,全面接收设计计算平台和可靠性分析平台中确定的设计参数,快速构造和修改零件、产品模型,快速生成符合要求的零件和产品工程图。因此,能够极大地提高设计效率,避免人为设计过程中信息的遗漏。同时,本文将Pro/E中的LAYOUT(布局)功能与其二次开发技术相结合,成功解决了装配体模型的参数化设计问题,从真正意义上实现了机械产品设计的智能化和敏捷化。(4)开发了往复式压缩机的虚拟可靠性试验系统。利用设计好的三维零件和产品模型,基于VC++编程技术,采用ANSYS/LS-DYNA软件结合APDL二次开发语言,搭建虚拟试验的系统平台。考虑到制造、装配的误差和材料属性的随机性对机械系统寿命可靠性的影响,对压缩机的传动机构进行动态的虚拟仿真,获得关键零部件的虚拟试验数据;分析数据的分布类型,计算关键件的可靠度,从而考核整个传动系统的可靠性。此外,为解决多因素耦合作用结构的强度分析问题,对压缩机的活塞杆进行虚拟试验研究;基于响应面方法分析虚拟试验数据,建立极限状态方程,计算活塞杆的疲劳强度可靠度及各影响因素的灵敏度,为现实中的设计工作提供指导。(5)对往复式压缩机活塞杆的螺纹连接结构提出了改进措施。基于上述分析研究的结果,针对目前活塞杆疲劳断裂事故频发的事实,在螺纹连接理论分析的基础上,提出一种结构改进的方案。并且,经过理论计算和ANSYS仿真分析,证明改进后的结构方案能够大大提高活塞杆的疲劳寿命。更多还原

【Abstract】 Large mechanical products were used in all sectors of the national economy widely, and their reliability, economy and safety are symbols of development level of state mechanical industry. At present, situation of safe production is still severe. As a result of large equipment fault, serious accidents that cause heavy economical loss, even personal injury and death, are too numerous to enumerate. At the same time, the competition among manufacturing market becoming more and more severe, the cycle of design, test, production and occupying market are key factors impacting on survival and development of relative enterprises. How to design economical and reliable mechanical products agilely and quickly is always very important matter to scientific and technical personnel in engineering.Reciprocating compressor has many merits, such as its pressure range is wide, thermal efficiency is high and applicability is better etc, so it is indispensable equipment in petroleum exploitation and chemical synthesis fields. Presently the problems for reliability, economy and flexibility of reciprocating compressor product become increasingly outstanding, because of its large structure, long design period and high manufacturing cost etc. Furthermore because more of these mechanical products are small-batch, even single production, it is very difficult to go on research on large sample test; at the same time, demands of users are changeful constantly, so rapid reaction to the market is very necessary. Therefore it has practical significance that study on reliability evaluation, agile design and virtual test about reciprocating compressor.The paper regards large reciprocating compressor as study case, combine reliability theory with compute technology, put forward the concept of digital study to go on research on analysis, design and simulation of mechanical products; at the same time, the paper improved on the part structure of reciprocating compressor based on research, and methods of theory calculation and simulation analysis were used to verify rationality and validity of improved structure. The detail contents of the paper are as following:(1) The paper developed a program platform for design calculation of reciprocating compressor. The platform can go on complicated thermodynamics and dynamics calculation handily, and get all kinds of design data and load graphs rapidly and accurately using VC++ and Matlab software, and provide basis for checking strength of key parts and building systems of design and simulation.(2) The paper developed a program platform for reliability sensitivity analysis of key parts. Based on reliability theory and considering various influencing factors (such as size tolerance, material property and machining process etc) completely, the paper built mathematic models of strength reliability analysis of key parts; and come true visualized and programmed course of analysis using VC++6.0. The platform can quantitatively provide scientific and accurate data of estimation reliability of key parts through probability; and give study on the influence of various factors on reliability, and provide theoretical basis for determining and controling design parameters reasonably.(3) The paper developed a software system of parametric design of reciprocating compressor. The software system received all determined design information coming from design calculation platform and reliability analysis platform to construct and modify 3-D models of parts and product rapidly and regenerate relative working drawings based on Pro/E and Pro/TOOLKIT. So it can improve design efficiency greatly and avoid the phenomena of information loss in human design. At the same time, the paper combined LAYOUT function of Pro/E with its second development technology, and solve the problem of parametric design for assemble models successfully, and come true intelligent and agile design of mechanical products indeed.(4) The paper developed a software system of virtual reliability test of reciprocating compressor. The designed 3-D models of parts, ANSYS/LS-DYNA, APDL and VC++ were used to build system platform of virtual test. Considering the influences of machining tolerance and property randomness of material on life reliability of mechanical system, dynamic virtual simulation of transmission mechanism of compressor was done and virtual test data of key parts was got; distribution type of data was analyzed and reliability of key parts was calculated to estimate reliability of whole transmission system. Moreover response surface method was used to go on study of virtual test on piston rod of compressor to solve the problem for strength analysis of multi-factors coupling action structure, and sensitivity of various influencing factors were analyzed, and reliability of structure was calculated to direct real design work.(5) The paper proposed the improved measure on thread connector of piston rod of reciprocating compressor. Based on the result of above study and pointed to the facts that piston rod always causes fatigue fracture, the improved method of structure was proposed. Moreover it was verified that the improved method of structure can improve fatigue life of piston rod greatly with theory calculation combining simulation analysis of ANSYS.更多还原