振动台固频调谐的弹性支承变刚度装置结构设计计算

介绍了振动台固频调谐的弹性支承变刚度装置结构设计及传动计算。采用阿线盘传动特性实现三个移动支座定心同步径向移动,以同步改变三根弹性支承梁悬伸量而达到调频的目的。通过变刚度装置结构方案、弹性支承梁尺寸和阿线盘传动动力等设计计算和样机试验,固频调谐效果显著;弹性支承调节为50-300mm时,能保证系统固频在10-120Hz内调谐,具有较好的实用价值。     

对三维强化抛光振动台变刚度调谐固频的研究

对三维强化、抛光振动台变刚度弹性支承调谐固频的问题进行了探讨,为三维振动台的动态特性实验提供理论依据。     

强化抛光振动台固频调谐的变刚度调节装置设计

在弹性支承梁变刚度调谐固频可行性的理论分析基础上，确立了由电动激振方式的振动系统和阿基米德螺线盘(阿线盘)传动组成的变刚度调节装置的总体设计方案，并对阿线盘、移动支座下端爪齿、传动受力情况等的设计要点进行了分析与计算。装置运行表明，这种装置以调节弹性支承梁刚度方式调谐振动系统固频效果显著，该装置设计具有实用价值。     

三维振动台的仿真设计

振动强化、抛光技术用于对复杂异型曲面工件进行表面强化、抛光处理。在三维强化、抛光振动台数学建模的基础上，用Matlab建立了仿真程序，并与结构设计同步进行，采用交互式方式确定了变刚度的结构设计参数。实际结果表明：这种设计方式是非常有效的。     

基于CE三维振动强化抛光装置变刚度调节系统设计研究

三维振动强化抛光技术可解决复杂曲面工件强化抛光工艺的迫切需要。针对三维振动强化抛光装置核心变刚度调节系统优化设计,采用基于并行工程设计方法,设计过程实现信息及时反馈,改进不合理设计,达到缩短三维振动强化抛光装置开发周期、降低成本、提高产品设计质量目的。     

共振在异型曲面零件强化抛光中的应用研究

介绍了三维振动台的结构原理和变刚度调谐原理,研制了变刚度试验装置,并研究了共振在变刚度系统中能量和振幅变化情况。实验表明在共振状态下能耗较低;在能耗降低一半的情况下,振动强度反而比非共振状态大10倍以上。经过发动机叶片在共振状态下进行强化抛光处理,表面粗糙度和疲劳强度都得到了大幅度改善,且减少了加工时间,降低了能耗。     

三维振动台的正弦扫频分析与模态分析

三维振动台采用振动方法完成对复杂异型曲面工件进行表面强化和抛光处理，为了探讨振动台的固频与振型对强化抛光的影响，本文首先对三维振动台进行Y向与Z向模态试验，得到了三维振动台的各阶模态，为了纵模态分析中确定强化抛光用模态，将模态分析中所得的各阶固频，对三维振动台进行正弦激振，同时将模态分析与正弦激振相结合，获得了适合三维振动台的抛光工艺模态。     

含弹性环的机器人关节变刚度驱动器设计分析

针对机器人与人共享工作环境所带来的人机交互安全问题及工作能耗大、效率低等问题,提出了一种含有弹性环的机器人关节变刚度驱动器;运用解析法分析了弹性环的刚度特性,得到其理论最大偏转角为1.5°;通过碰撞和抛球实验验证了所设计的关节驱动器的实际缓冲和储能效果;结果表明:所设计的含有弹性环的机器人关节变刚度驱动器具有良好的吸收冲击的能力,最大偏转角约为1.7°,可有效保护碰撞发生时的人机安全。同时,储能效果明显,可提高能量使用效率。     

瓦块固有频率对可倾瓦轴承频变刚度的影响

为研究轻载工况下可倾瓦块固有频率和振动频率对轴承刚度的影响,基于长轴承理论建立求解可倾瓦推力轴承瓦块固有频率和频变刚度的润滑和动力学耦合模型,推导润滑模型的解析解和频变动力学特性的表达式,并通过实例计算分析载荷、支点系数(瓦进油边到支点的距离与瓦长的比值)、瓦块转动惯量等结构参数对瓦块固有频率和频变刚度的影响。结果表明:瓦块的惯性、油膜的刚度和阻尼共同决定瓦块振动的固有频率,瓦块在固有频率附近振动可以使轴承的频变刚度出现负值,甚至正负无穷大;小载荷的瓦(如非承载瓦)容易出现瓦块振动频率接近其固有频率的状况,使瓦发生共振;可倾瓦轴承设计中有必要考虑瓦块的固有频率和频变刚度来设计非承载瓦的支点系数和转动惯量,使瓦块的振动频率跨过固有频率而产生大的刚度。     

“O型”橡胶圈支承件动力学参数的频变特性研究

论述了化纤长丝卷绕机筒管夹头系统中"O型"橡胶圈支承件动力学参数的频变特性测试方法和原理,对"O型"橡胶圈支承件的动力学参数的频变特性进行了测试研究。根据试验所得的刚度系数-频率曲线以及阻尼系数-频率曲线变化规律,运用非线性最小二乘拟合出"O型"橡胶圈支承件的动力学参数频变特性方程,可为化纤长丝卷绕机筒管夹头支承系统的频变参数动力学分析设计提供重要支撑。     

基于DFM三维振动强化抛光装置优化设计

利用并行工程下，面向可制造的产品设计方法，优化设计无导轨支承三维振动强化抛光装置。设计中实现及时提供反馈信息、改进不合理设计，从而达到缩短三维振动强化抛光装置开发周期、降低成本及提高产品设计质量的目的。     

Fundamental frequency and testing mode of complicated elastic clamped-plate vibration

Aimed at the modal analysis of complicated elastic clamped-plates, a trigonometric interpolation method of conformal mapping is applied to set up the mapping function between a complicated region and a unit dish region, and the fundamental frequency of the complicated vibrating region is analyzed with the help of the Galerkin method. Taking an elastic rectangle-plate with arc radius as an example, the testing mode frequency band of plates is determined by analyzing the fundamental frequency; meanwhile, according to hamming testing method of multi-point excitation to the single-point response, and by signal processing technology and its software programming, modal parameter recognition of the elastic clamped-plate is completed. Comparing the first order modal frequency with the theoretical fundament frequency, the validity of the testing mode method and theoretical analysis are verified.     

Conformal analysis of fundamental frequency of vibration of elastic clamped plates

To calculate the fundamental frequency of vibration of special-shaped and elastic clamped plates, the conformal mapping theory is adopted to separate the interpolating points of a complicated boundary into odd and even sequences, both of which can be mutually iterated, so that the conformal mapping function between the complicated region and the unit dish region is established. Trigonometric interpolation and convergence along the normal direction methods are provided, and the complex coefficients of the conformal mapping function are calculated. Galerkin method is used to obtain the solution of fundamental frequency in the vibrating differential function of the complicated vibrating region. Finally, taking ellipse elastic clamped plates as an example, the effects on fundamental frequency coefficient caused by eccentric ratio e and area size are analyzed. __________ Translated from Engineering Mechanics, 2006, 23(10): 73–76 [译自: 工程力学]     

求解非均质变截面轴扭转振动固有频率的混合状态方法

本文给出了均质等截面轴扭转振动的混合状态方程及其解。对于非均质变截面轴，可以把它划分为很多微段，然后，利用段与段之间的连续条件推出一个传递公式，最后，利用边界条件可将固有频率求出。     

岸边集装箱桥式起重机钢结构小车运行方向振动固有频率的简易测试

根据岸边集装箱桥式起重机的结构特点,简化框架模型,采用简单易行的光点投影测试方法,进．行小车运行方向的振动周期及固有频率的测试,以对整机钢结构的动刚度进行检验和评估。     

Modelling of viscoelastic damper support for reduction in low frequency residual vibration in machine tools

Residual vibrations deteriorate the accuracy and productivity of precision machine tools. Rocking vibration is excited by feed motion. Rocking vibration is the mode in which the entire machine vibrates and is the main source of residual vibrations at low frequencies. The characteristics of rocking vibration are influenced by the characteristics of the machine support structure. Thus, it is necessary to increase the damping of the machine support structure to reduce the residual vibrations caused by rocking vibration. In addition, it is important for machine tools to be stiff to reduce vibrations caused by the acceleration of feed drives. Conventional passive damper supports decrease the stiffness of a machine support structure while increasing the damping. Consequently, a passive viscoelastic damper system is developed to increase support damping without decreasing stiffness by focusing on the horizontal component of rocking vibration. However, the proposed damper damping capacity has a magnitude dependency. This makes it difficult to quantitatively determine the damper area in machine tools to reduce rocking vibrations to the required level. In this study, the developed damper is modeled using a viscoelastic four element model. Because of the nonlinearity of the model, an iterative time domain calculation method is introduced for the simulation. This method enables us to quantitatively estimate the effect of the damper on the machine tool. Based on the model proposed in this study, the proposed damper system can be applied to various machine tools to reduce the residual vibration without adjusting the damper area on the machine tool by a trial and error method.