振动时效法消除结构残余应力技术研究

发布时间：2018-04-03 00:29

本文选题：振动时效　切入点：X射线衍射法　出处：《北京理工大学》2015年硕士论文

【摘要】：本文以整机装配体及外框架、内框和反射镜总成等零部件为研究对象，针对传统试验法对结构时效振动参数上的选择，以及对复杂装配体多方向残余应力消除不均的问题，利用X射线衍射法测量结构实际的残余应力分布情况，采用有限元仿真确定时效参数，进行振动时效处理，建立结构零部件、整机装配体结构消应力最佳的工艺，最终达到确定结构最佳振动时效参数的目的。首先使用X射线衍射法对各结构残余应力分布的具体情况进行了测量和研究。根据所选结构材料属性和X射线测量的特点，采用了X射线衍射法中的sin2Ψ法对结构残余应力情况进行了测量。运用X射线测得整机装配体、外框架、内框及反射镜总成结构所选点的残余应力大小。运用有限元分析软件HYPERMESH和ANSYS建立了外框架、内框和反射镜总成结构的有限元模型，并进行了约束模态分析。对各零部件结构进行谐响应分析，依次取不同的激振频率和激振力幅值，计算结构的最大动应力，并依据仿真结果建立结构最大动应力与激振频率和激振力幅值的关系曲线。根据仿真结果选择了反射镜及“法兰盘+支架”结构的激振频率、激振力、激振点、支撑点等时效参数。采用频谱谐波时效法对整机装配体进行残余应力应力消除试验。由于整机装配体结构复杂，残余应力分布多样化，传统的振动时效已经不能满足应力消除需求。运用有限元法建立整机装配体模型，得到装配体约束下的固有频率及模态振型，选取其中5个对关键部位振动影响较大的振型作为主振型，进行混合叠加施振，消除和均化各方向的残余应力。根据有限元法确定了整机零部件结构的振动时效参数，组建振动消应力试验装置对外框架、内框和反射镜总成结构进行振动时效处理。测量试验后结构的残余应力分布情况，分析时效结果；利用正交实验法，以外框架和反射镜总成结构作为试验对象，通过对5组不同试验参数的时效效果进行对比分析，进行振动时效工艺参数优化。以试验结果为基础，分析不同结构试验结果，得到结构材料对振动时效效果的重要性这一结论，，为进一步进行振动时效理论分析提供了基础。
[Abstract]:In this paper, the components such as the whole machine assembly, the outer frame, the inner frame and the mirror assembly are taken as the research object, aiming at the selection of the structural aging vibration parameters by the traditional test method, as well as the problem of eliminating the uneven multi-direction residual stress of the complex assembly.The actual residual stress distribution of the structure was measured by X-ray diffraction method, the aging parameters were determined by finite element simulation, the vibration aging treatment was carried out, the structural parts and components were set up, and the optimum process of stress relief for the whole assembly body structure was established.Finally, the purpose of determining the optimum vibration aging parameters of the structure is achieved.The distribution of residual stress in various structures was measured and studied by X-ray diffraction.According to the properties of the selected structural materials and the characteristics of the X-ray measurement, the residual stress of the structure was measured by using the sin2 蠄 method in the X-ray diffraction method.The residual stress of the assembly, frame, inner frame and mirror assembly of the whole machine was measured by X ray.The finite element model of the outer frame, inner frame and mirror assembly is established by using the finite element analysis software HYPERMESH and ANSYS, and the constrained modal analysis is carried out.The harmonic response of each component structure is analyzed and the maximum dynamic stress of the structure is calculated according to the different frequency and amplitude of the excitation force. The relationship between the maximum dynamic stress of the structure and the frequency and amplitude of the exciting force is established based on the simulation results.According to the simulation results, the time-dependent parameters such as frequency, force, point and support point of the mirror and flange bracket are selected.The residual stress relief test of the whole machine assembly was carried out by using the spectrum harmonic aging method.Because of the complex structure of the assembly body and the diversity of residual stress distribution, the traditional vibration aging can no longer meet the requirement of stress elimination.The finite element method is used to establish the assembly body model of the whole machine. The natural frequencies and modal modes under the constraints of the assembly body are obtained. Five of the vibration modes which have a great influence on the vibration of the key parts are selected as the main vibration modes, and the mixed superposition vibration is carried out.Eliminate and homogenize the residual stresses in all directions.According to the finite element method, the vibration aging parameters of the whole machine parts structure are determined, and the external frame, inner frame and mirror assembly structure of the vibration stress relief test device are set up for vibration aging treatment.The residual stress distribution of the structure after the test was measured and the aging results were analyzed. By using the orthogonal test method, the structure of the outer frame and the mirror assembly as the test object, the aging effect of five groups of different test parameters was compared and analyzed.The process parameters of vibration aging were optimized.Based on the experimental results, the importance of structural materials to vibration aging effect is obtained by analyzing the results of different structural tests, which provides a basis for further theoretical analysis of vibration aging.
【学位授予单位】：北京理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG156.92

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