轴类零件结构工艺性设计缺陷及材料选择设计缺陷的辨识
发布时间：2019-05-15 00:33
【摘要】：轴类零件是机械系统中的重要组成部分,应用非常广泛,此类零件一旦发生失效,轻则使机械运转停止无法正常工作、重则造成机毁人亡等无法挽回的损失。由于轴类零件的设计工作相当繁琐,在设计过程中一旦出现差错就可能造成轴系乃至整套设备的失效。本文以轴类零件的结构工艺性设计缺陷和材料选择设计缺陷为研究对象,采用不同的方法对其进行了辨识。经验不足的设计人员设计出的零件结构很可能会存在加工费用高、无法加工等缺陷,为此,本文提出了一种基于特征元推理策略的轴类零件结构工艺性设计缺陷辨识方法。轴类零件的结构特征承载着零件中的所有结构设计信息,将轴类零件的设计信息存储在零件信息树中,建立了特征元知识库,提出了基于特征元的推理策略,并采用该推理策略对轴类零件的结构工艺性设计缺陷进行了辨识。过盈配合中过盈量的传统计算方法忽略了配合边缘的应力集中问题,过大的边缘应力会造成轴毂配合部分压溃或微动磨损等,为解决传统计算方法的不足,提出了基于有限元方法与支持向量机模型的过盈量设计缺陷辨识方法。采用有限元方法分析出过盈配合接触应力的影响因素,并用支持向量机构建出了过盈量及其影响因素之间的关系模型,利用该模型可以精确地计算出发生塑性变形时的最大过盈量,若原设计过盈量超过了计算出的最大过盈量,则可以确定原设计存在着过盈量设计缺陷。传统的滚珠丝杠抗过载能力设计,忽略了螺旋升角的影响。本文在综合考虑到螺旋升角以及滚珠载荷分布不均的影响,对已有的滚珠丝杠接触力学模型进行了改进,推导了在临界塑性变形下临界轴向载荷的计算公式,据此公式可以判断滚珠丝杠是否存在结构参数设计缺陷。材料选择是一个多目标决策过程,考虑不周很容易造成选材不满足设计要求,为此,提出了一种基于改进物元模型的材料选择设计缺陷辨识模型。对物元模型中隶属度的计算方法进行改进,引入数值型关联度和区间型关联度,克服了无法对区间物元进行计算的不足之处。应用改进的物元模型计算出各备选材料的等级隶属度和等级特征值,由这两个参数就可判断备选材料是否存在设计缺陷。
[Abstract]:Shaft parts are an important part of mechanical system, which are widely used. Once this kind of parts fail, the machinery can not work properly when it fails, and the irreparable losses such as machine destruction and human death will be caused by heavy ones. Because the design work of shaft parts is very tedious, once there is an error in the design process, it may cause the failure of shafting and even the whole equipment. In this paper, the structural process design defects and material selection design defects of shaft parts are taken as the research object, and the structural process design defects and material selection design defects of shaft parts are identified by different methods. The part structure designed by inexperienced designers is likely to have some defects, such as high machining cost and inability to machine. therefore, this paper proposes a defect identification method for structural process design of shaft parts based on feature element reasoning strategy. The structural features of shaft parts carry all the structural design information in the parts. The design information of shaft parts is stored in the part information tree, the feature element knowledge base is established, and the reasoning strategy based on feature elements is put forward. The structural process design defects of shaft parts are identified by using the reasoning strategy. The traditional calculation method of interference amount in interference fit ignores the problem of stress concentration at the edge of fit, and excessive edge stress will cause partial crushing or fretting wear of hub fit, etc., in order to solve the deficiency of traditional calculation method. A defect identification method for interference design based on finite element method and support vector machine model is proposed. The influencing factors of interference fit contact stress are analyzed by finite element method, and the relationship model between interference and its influencing factors is established by using support vector mechanism. The maximum interference in plastic deformation can be calculated accurately by using the model. If the interference of the original design exceeds the calculated maximum interference, it can be determined that there is a defect in the design of the original design. The traditional design of anti-overload ability of ball screw ignores the influence of spiral angle. In this paper, considering the influence of spiral angle and uneven distribution of ball load, the existing contact mechanical model of ball screw is improved, and the formula for calculating critical axial load under critical plastic deformation is derived. According to this formula, we can judge whether there are structural parameter design defects in ball screw. Material selection is a multi-objective decision-making process, which is easy to cause material selection not to meet the design requirements. Therefore, a defect identification model of material selection design based on improved matter-element model is proposed. The calculation method of membership degree in matter-element model is improved, and the numerical correlation degree and interval correlation degree are introduced to overcome the shortcomings that can not be used to calculate interval matter-element. The grade membership degree and grade eigenvalue of each alternative material can be calculated by using the improved matter-element model, and the design defects of the alternative material can be judged by these two parameters.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TH16;TH133.2
本文编号：2477173
[Abstract]:Shaft parts are an important part of mechanical system, which are widely used. Once this kind of parts fail, the machinery can not work properly when it fails, and the irreparable losses such as machine destruction and human death will be caused by heavy ones. Because the design work of shaft parts is very tedious, once there is an error in the design process, it may cause the failure of shafting and even the whole equipment. In this paper, the structural process design defects and material selection design defects of shaft parts are taken as the research object, and the structural process design defects and material selection design defects of shaft parts are identified by different methods. The part structure designed by inexperienced designers is likely to have some defects, such as high machining cost and inability to machine. therefore, this paper proposes a defect identification method for structural process design of shaft parts based on feature element reasoning strategy. The structural features of shaft parts carry all the structural design information in the parts. The design information of shaft parts is stored in the part information tree, the feature element knowledge base is established, and the reasoning strategy based on feature elements is put forward. The structural process design defects of shaft parts are identified by using the reasoning strategy. The traditional calculation method of interference amount in interference fit ignores the problem of stress concentration at the edge of fit, and excessive edge stress will cause partial crushing or fretting wear of hub fit, etc., in order to solve the deficiency of traditional calculation method. A defect identification method for interference design based on finite element method and support vector machine model is proposed. The influencing factors of interference fit contact stress are analyzed by finite element method, and the relationship model between interference and its influencing factors is established by using support vector mechanism. The maximum interference in plastic deformation can be calculated accurately by using the model. If the interference of the original design exceeds the calculated maximum interference, it can be determined that there is a defect in the design of the original design. The traditional design of anti-overload ability of ball screw ignores the influence of spiral angle. In this paper, considering the influence of spiral angle and uneven distribution of ball load, the existing contact mechanical model of ball screw is improved, and the formula for calculating critical axial load under critical plastic deformation is derived. According to this formula, we can judge whether there are structural parameter design defects in ball screw. Material selection is a multi-objective decision-making process, which is easy to cause material selection not to meet the design requirements. Therefore, a defect identification model of material selection design based on improved matter-element model is proposed. The calculation method of membership degree in matter-element model is improved, and the numerical correlation degree and interval correlation degree are introduced to overcome the shortcomings that can not be used to calculate interval matter-element. The grade membership degree and grade eigenvalue of each alternative material can be calculated by using the improved matter-element model, and the design defects of the alternative material can be judged by these two parameters.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TH16;TH133.2
【参考文献】
相关期刊论文 前4条
1 范守文;熊静琪;邵旭光;黄洪钟;胡天友;;机电产品的可验证设计系统及其实现框架[J];计算机集成制造系统;2010年06期
2 郭丽娟;孙世宇;段修生;;支持向量机及核函数研究[J];科学技术与工程;2008年02期
3 郭金玉;张忠彬;孙庆云;;层次分析法的研究与应用[J];中国安全科学学报;2008年05期
4 李凌丰;刘彩芬;;滚珠丝杠副轴向变形分析[J];中国机械工程;2011年07期
，本文编号：2477173
本文链接：https://www.wllwen.com/kejilunwen/jixiegongcheng/2477173.html
