非线性共振式与耦合共振式振动时效新装备的机理与设计理论研究

Vibration aging is an effective method to reduce residual stress, which has the characteristics such as pollution-free, high efficiency, low cost of time and energy, cost saving etc. How to achieve the resonance and dynamic stress so as to reduce the residual stress of high stiffness workpieces remains a hot potato because the exciting frequency of traditional vibration aging devices is far lower than the natural frequency of the workpieces. Two methods are proposed to solve the above-mentioned problem in this project. The first one is based on the principle that the response frequency can be different with the exciting frequency, which makes traditional exciter act on nonlinear vibration system to generate a much higher vibration frequency, such as superharmonic resonance frequency or combination resonance frequency. This nonlinear vibration system then acts on a workpiece to achieve the primary resonance and dynamic stress needed to reduce the residual stress with a vibration frequency as high as the natural frequency of the high stiffness workpiece. The second one is to use combination dynamic stress of the bending- torsional coupling resonance of the workpieces. The mechanisms of the two methods to reduce residual stress and the design theories of new devices are studied in this project, which will enlarge the types of workpieces in the application fields of vibration aging.The project is with high academic value and good application prospect, which also satisfies the needs of national energy conservation and emission reduction.

振动时效是消减工件残余应力的一种有效手段，具有无污染、效率高、节约时间、能源、费用等特点。因为现行振动时效装置的激振频率远小于高刚度工件的固有频率,如何实现高刚度工件的共振和动应力以消减残余应力一直是十分棘手的问题。本项目提出两种应用振动时效消减高刚度工件残余应力的方法。其一是依据非线性振动系统的响应频率可不同于激励频率的原理，采取现行激振器作用于非线性振动系统使其产生远高于原激振频率的超谐共振或组合共振，该非线性振动系统再以接近高刚度工件固有频率的新激振频率作用于工件，使其产生共振和相应的动应力以消减工件的残余应力。其次是研究通过工件弯扭耦合共振的组合动应力来消减其的残余应力。项目研究这两种方法消减工件残余应力的机理和新装置的设计理论。使适合采用振动时效方法消减残余应力的工件类型大为增加，应用领域得到很大的扩展，项目具有较高的学术价值和很好的应用前景，也符合当前国家节能减排工作的需要。

针对现行振动时效设备所能产生的激振频率远低于高刚度构件的固有频率，难实现主共振产生振动时效所需动应力难题，提出两种方法。其一是依据非线性振动原理，采用现行激振器作用于非线性振动系统使其产生远高于原激振频率的超谐共振或组合共振，使工件产生主共振和相应的动应力以消减残余应力。其次是以高刚度轧辊为结合点，研究通过工件弯扭耦合共振产生的组合动应力来消减其的残余应力。.以45钢为结合点，研究了构件残余应力分布情况。通过修正的45钢有限元仿真本构模型及对机加工和热处理连续工艺产生的耦合残余应力场的大小和分布进行研究，并以大量X射线、盲孔法和磁测法获得的数据进行对比，初步获得多工序加工工件后残余应力叠加的规律。以确定工件整体残余应力的分布，从而获得振动时效构件的振型、振幅、动应力的分布大小等相应参数。 .建立轧辊等高刚度零件的超谐共振数学模型，通过反演理论得到产生超谐共振所需非线性弹簧、阻尼的参数，并用实验验证其正确性。应用多尺度法研究消减构件残余应力所要求的共振频率、振型、激振力与非线性振动激振系统的质量、弹性等参数间关系。为方便研究，将构件简化为弹性元件作用于非线性激振系统。分析了激振系统作用于构件后，为实现构件产生共振，激振系统的非线性参数所进行的调整。按照调整后的参数搭建了非线性共振式振动时效系统试验平台，对非线性共振式振动时效新方法进行验证。通过系统研究，初步建立了非线性超谐共振式振动时效装置的设计理论。.此外运用有限元方法建立转子－轴承系统的弯扭耦合模型。通过数值方法进行模态分析，得到转子－轴承系统的固有频率和振型，得到弯曲刚度、扭转刚度、支撑性质、偏心大小、外部激励的关系，由此来设定转轴的弯扭共振条件参数。通过以上的理论分析，设计了弯扭耦合共振式振动时效装置并进行实验，通过对动应变、动应力、残余应力的检测，验证了理论分析结果。.部分研究成果已经在企业得到应用，获得广西技术发明奖三等奖。