非线性共振式振动时效方法及应用研究

发布时间：2018-03-15 00:21

本文选题：非线性　切入点：振动时效　出处：《广西大学》2014年博士论文　论文类型：学位论文

【摘要】：振动时效是消减残余应力的一种有效手段,与自然时效及热时效方法相比,振动时效具有无污染、效率高、成本低、节约时间和能源等特点,在避免热时效过程可能产生构件氧化、构件受热不均而导致裂变或在冷却过程中产生新的应力等方面也具有益处,但至今其应用范围还很有限,还有很大的潜力还没有发挥出来。其中一个重要原因是现行振动时效设备所能产生的激振频率(大都小于200Hz)远低于许多构件的固有频率,无法使构件产生振动时效所要求的共振和动应力。此外部分构件需要较高阶振型以产生相应的动应力来消减残余应力,所以要求振动时效设备能产生较高的激振频率。针对这一问题,依据非线性振动系统的输出响应频率可不同于输入激励频率的原理,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非线性共振,该非线性振动系统再以接近具有较高固有频率构件共振频率的新激振频率作用于构件,使其产生共振和相应的动应力以消减构件的残余应力。本文研究了非线性共振式振动时效方法及应用研究,主要研究内容包括以下几个部分： (1)遵循“加载的动应力与残余应力的叠加大于材料的屈服强度可获得残余应力的减少”准则,要有效消减构件的残余应力,需要了解构件的残余应力的分布规律,以确定所需动应力的分布大小及相应构件的振型与振幅等。本文以等温淬火曲轴为结合点,应用热弹塑性有限元方法分析曲轴经过等温淬火工序后的残余应力分布规律,然后应用有限变形理论分析切削加工工序后的残余应力分布规律,再运用应力叠加原理得到曲轴在等温淬火和切削加工这两道工序后的残余应力分布规律,为构件振动时效所需动应力的分布提供技术依据。 (2)为获取实现消减等温淬火曲轴残余应力所需要的振动动应力,在等温淬火曲轴残余应力分布规律的基础上,利用有限单元法建立曲轴的动力学方程,获取等温淬火曲轴在外部激励和自激惯性力作用下的动态特性,分析等温淬火曲轴各阶振动模态下的动应力分布规律,并确定满足消减残余应力所需要的共振频率、振型、激振力大小等参数。 (3)研究在传统激振器作用下的非线性激振系统的动态特性。建立系统非线性动态分析模型,应用非线性振动理论的多尺度法研究激振块的振动频率、产生的激振力与非线性弹性参数之间的关系和规律,由可解性条件分析消减较具有高固有频率构件残余应力所要求的共振频率、振型、激振力等与非线性振动激振系统的质量、弹性等参数问关系。为了研究构件对非线性激振系统动态特性的影响,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。 (4)以等温淬火曲轴为例,根据本文的理论研究结果设计一种新型非线性共振式振动时效装置。利用有限单元法计算选取等温淬火曲轴非线性共振式振动时效装置的支撑及夹持方式等各项工艺参数,建立等温淬火曲轴与非线性共振式振动时效装置组成的非线性振动时效系统动力学模型。利用多尺度法对动力学模型进行分析,确定非线性共振式振动时效装置所需的结构及非线性元件等参数。为等温淬火曲轴非线性共振式振动时效装置的研制提供依据。 (5)以上述研究为基础,研制等温淬火曲轴非线性共振式振动时效系统试验平台,通过试验对非线性振动系统的输入及响应进行分析,并将实验分析结果和理论分析结果进行对比,对非线性共振式振动时效新方法进行验证。
[Abstract]:The VSR is an effective means to reduce the residual stress, compared with natural aging and thermal aging method, vibration aging has no pollution, high efficiency, low cost, saving time and energy and other characteristics, to avoid thermal aging process may produce components of oxidation, uneven heating component caused fission or create new stress in the process of cooling and other aspects also have benefits, but its application is still very limited, there is still great potential has yet to play out. One important reason is that the excitation frequency can produce current vibration aging equipment (mostly less than 200Hz) is far lower than the natural frequency of many components, the component cannot produce resonance vibration aging required and dynamic stress. In addition some components need higher order modes to produce the corresponding dynamic stress to reduce residual stress, vibration frequency so that vibration aging equipment can produce higher.
To solve this problem, based on the principle of nonlinear vibration system output frequency response can be different from the input frequency, take the current exciter in nonlinear vibration system to produce nonlinear resonance far higher than the original excitation frequency, the nonlinear vibration system with high frequency component near the resonant frequency of the new excitation frequency acting on the component, to produce resonance and the corresponding residual stress to reduce the stress of components. This thesis studied the nonlinear resonance vibration aging method and application, the main contents are as follows:
(1) follow the load dynamic yield strength superposition force and residual stress is greater than the material available to reduce the criterion of residual stress, to effectively reduce residual stress of components, need to understand distribution of components of the residual stress, to determine the desired shapes and amplitudes of dynamic stress distribution the size and the corresponding component. In this paper the isothermal quenching crankshaft is proposed, using thermal elastic-plastic finite element method analysis of crankshaft after isothermal quenching process, the residual stress distribution, and then apply the theory of finite deformation analysis of machining process of the residual stress distribution, and then use the crankshaft in the two residual step austempering and cutting after the stress distribution of the stress superposition principle, required for component vibration aging distribution of dynamic stress and provide technical basis.
(2) in order to obtain the vibration elimination of residual stress of crankshaft isothermal quenching to dynamic stress, based on the residual stress distribution of the crankshaft isothermal quenching on the kinetic equation by finite element method to establish the crankshaft, obtain the dynamic characteristics of crankshaft isothermal quenching inertial force under the action of external excitation and self excitation, modal analysis the isothermal quenching the vibration under the dynamic stress distribution law, and determined to meet the subtractive resonance frequency, residual stress to vibration mode, the vibrating force and other parameters.
(3) research on the dynamic characteristics of nonlinear vibration system in traditional vibration force. Establish the analysis model of nonlinear dynamic system, the application of nonlinear vibration theory the method of multiple scales vibration block vibration frequency, the relationship and regulation between exciting force and nonlinear elastic parameters generated by the solvability condition analysis cut with the resonance frequency, high frequency components of residual stress required for vibration mode, vibration force and mass nonlinear vibration excitation system, elastic parameter q relationship. In order to study the influence of components on dynamic characteristics of nonlinear vibration system, the component is simplified to the action of the elastic elements in the nonlinear vibration system. Analysis of the effect of excitation system on the component, resonance for component of nonlinear parametric excitation system adjustment.
(4) the isothermal quenching crankshaft as an example, according to the results of the design of a new type of nonlinear resonance vibration ageing device. The calculation supporting and clamping mode of the process parameter of isothermal quenching crankshaft nonlinear resonance vibration ageing device using the finite element method, the establishment of the isothermal quenching crankshaft and nonlinear resonance vibration aging device dynamic nonlinear vibration aging system model components. Using multi-scale method to analyze the dynamic model of nonlinear resonance vibration ageing device required structure and nonlinear element parameter. To provide the basis for the development of Austempered crankshaft nonlinear resonance vibration ageing device.
(5) based on the research and development of testing platform of isothermal quenching crankshaft nonlinear resonance vibration aging system, through the response test of nonlinear vibration system input and analysis, and analyze the experimental results and the theoretical analysis, the new method of nonlinear vibration aging resonance is verified.

【学位授予单位】：广西大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU311.3;O322

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