低成本金属振动陀螺薄壁谐振子的调平方法

谐振子是金属振动陀螺的关键部件,其固有轴偏差和频差的参数性能直接影响到金属振动陀螺的精度。为了提高金属振动陀螺的性能,从陀螺的结构和工作原理出发,介绍了谐振子的能量损耗原因及其解决办法。在此基础上,通过质量调平原理,对质量不对称的谐振子采用动态调平方法消除薄壁金属圆柱体边缘的不均衡质量,以减小其固有轴偏差和频差。实验结果表明,调平后的谐振子频差小于0.1 Hz,固有轴偏差小于1°,相比调平前有数量级的提高,说明该方法有效的提高金属振动陀螺的整体性能。

金属振动陀螺谐振子性能参数的分析与研究

金属谐振子哥氏振动陀螺温度灵敏度高的原因是谐振子的品质因数(Q值)低。现代冶金技术可提供在温度变化时高稳定性和高Q值的合金,为实现高精度金属振动陀螺(CVG)打下了基础。通过从大量的合金材料中筛选符合金属振动陀螺要求的特殊材料进行研究与分析,并探讨了不同热处理工艺对材料性能、金属陀螺谐振子性能参数等的影响。实验结果表明,马氏体时效钢3J33对金属振动陀螺谐振子的性能参数优化有较好的效果。

无温度传感器的金属振动陀螺温度补偿

金属振动陀螺是一种低成本、长寿命的新型简并模谐振陀螺,其结构相对简单,加工相对容易实现。但是,金属材料的温度系数和热膨胀系数大,其受到温度变化的影响明显,温度漂移对器件最终性能的影响较为明显。因此,对金属振动陀螺进行温度补偿,可以显著提高器件性能指标。建立了金属振动陀螺的温度模型,确定环境温度对器件谐振频率和零位偏移的影响关系。研究发现,金属振动陀螺谐振频率的温度系数具有超高线性度,可以替代温度传感器的作用,直接用谐振频率作为温度补偿量的输入。基于温度模型,进一步建立了温度漂移补偿模型,计算金属振动陀螺谐振频率的温度系数和零位偏移的温度关系,并对金属振动陀螺的温度漂移进行补偿。通过实验结果验证,金属振动陀螺谐振频率的温度系数为0.0536 Hz/℃,线性度达3.4×10^(-6),零位偏移和温度呈二次曲线关系,温度补偿后,金属振动陀螺的随机漂移可降低65%左右。

浅谈金属振动测试的挖掘机故障诊断方法研究

挖掘机组成结构复杂，工作环境复杂性和工作强度较大，容易产生故障。采用挖掘机机体金属振动测试方法进行机械故障监测，实现故障诊断。提出一种基于机体金属壳体振动关联谱特征提取的挖掘机故障诊断方法。首先对目前的挖掘机机械故障诊断方法进行分析，介绍了采用金属壳体振动测试方法进行故障诊断的原理。然后进行故障特征提取和诊断的算法设计。以实际的挖掘机故障工况状态进行故障诊断的案例应用分析和仿真测试，实验结果表明，该方法进行故障诊断的准确识别性能较好，稳定可靠。

全金属固态振动陀螺机电耦合特性研究

对全金属固态振动陀螺(ASVG)的机电耦合特性展开了研究。提出一种利用多物理场有限元仿真模拟ASVG静电激励的检测方法,依据静电驱动与检测原理分析了不同的驱动方式对静电驱动力的影响,优化了电极结构参数,并得到了检测电容的静态误差。结果表明:ASVG的振幅与施加的交流电压与直流偏压呈正比关系,并在1倍谐振频率的驱动电压下,其振幅最大为4.5μm,并被激发至四波腹状态,优化后的电极角度为40°,静电电极与振子间距保持在5μm时,其最大振幅为2.3μm,基本满足设计要求。最后,通过实验得到ASVG的幅频特性与机电特性,验证了分析结果的正确性和可用性。

基于李指数泛函的飞机金属表面振动鲁棒性控制算法

飞机金属表面振动的运动的数学模型具有非线性和自扰动性，通过鲁棒性控制，保障飞机稳定飞行，提出一种基于李雅普洛夫指数泛函的飞机金属表面振动鲁棒性控制算法。通过算法改进和仿真实验，实现飞机控制系统优化，研究结果表明，该控制算法的鲁棒性较好，飞机扰动误差收敛到零。

金属壳体振动陀螺的多参数温度补偿技术研究

金属壳体振动陀螺具有结构简单,精度高、体积小,可靠性高,寿命长等显著优势,在军用和民用领域都有广阔的应用前景。由于受材料特性影响,金属壳体谐振结构的Q值很难达到极高的水平,使得金属壳体振动陀螺的零偏漂移受温度的影响比较显著。传统的温度补偿方法存在滞回效应,补偿效果不理想。针对该问题,提出了一种多参数温度补偿方法。理论分析结果表明,力反馈模式下,阻尼不均匀变化是引起陀螺零偏漂移的主要因素。根据理论分析结果,选取正交反馈量,温度、驱动电压等三个变量作为补偿量;通过全温区测试,建立陀螺零偏漂移与补偿量的数学模型,利用该模型对陀螺零偏漂移进行补偿。补偿后,陀螺的全温区零偏漂移由补偿前的300(°)/h减小为10(°)/h,而采用传统温度补偿方法后的零偏漂移为35(°)/h,验证了该方法的有效性。

金属振动陀螺调平方案设计与比较

金属振动陀螺是一种低成本、轻小型的新型固体波动陀螺,在战术级应用领域具有广大的应用前景。金属振动陀螺谐振子的频率分裂直接反映陀螺的性能指标,频率分裂可以通过机械调平的方式进行修正。对金属振动陀螺的调平方法进行了梳理和比较,提出了质量修正、刚度修正2种调平思路和增加、去除材料等5种修正方法。通过对各种调平修正方法的比较,选择激光去重法对谐振子顶面进行质量调平修正,并进行实验验证。实验结果表明,该方法修正后,在保持品质因数基本不变的情况下,谐振子的频率分裂由5.3Hz降低到0.9Hz,陀螺的零偏稳定性由55(°)/h降低到6(°)/h,性能指标提高了1个数量级。

纺织设备中金属旋转体振动的单片机测试系统

纺织机械中金属旋转体在旋转过程中由于自身的不平衡或安装不合理等原因引起振动 ,对设备的运行产生不良影响。本文提供一种用单片机测试系统测试金属旋转体振动的方法 。

Frictional characteristics of sheet metals with superimposed ultrasonic vibrations

The forming performance of sheet metals in the deep-drawing process with ultrasonic vibrations can be improved by the surface effect between the sheet metal and the die.A sheet metal friction test with ultrasonic vibrations is performed to explore the cause of the surface effect.The frictional characteristics are investigated,and the corresponding friction expressions are established based on the contact mechanics and the elastic–plastic contact model for rough surfaces.Friction is caused by the elastic–plastic deformation of contacting asperities under normal loads.The actual contacting region between two surfaces increases with normal loads,whereas the normal distance decreases.The normal distance between the contacting surfaces is changed,asperities generate a tangential deformation with ultrasonic vibrations,and the friction coefficient is eventually altered.Ultrasonic vibrations are applied on a 40Cr steel punch at the frequency of 20 kHz and the amplitude of 4.2μm.In the friction tests,the punch is perpendicular to the surface of the magnesium alloy AZ31B sheet metals and is sliding with a relative velocity of 1 mm/s.The test results show that the friction coefficient is decreased by approximately 40%and the theoretical values are in accordance with the test values;Ultrasonic vibrations can clearly reduce wear and improve the surface quality of parts.

Vibrational Spectra and Density Functional Theory Calculations of Metallotriphenylcorroles

The infrared absorption and Raman scattering spectra were measured for the metallotriph- enylcorroles （MTPCs, M=Cu, Co, Ni, Mn）. The ground-state structures and vibrational spectra of MTPCs have been calculated with the density functional theory. The observed Raman and IR bands have been assigned based on the calculation results. Due to the symmetry lowering, the vibrational spectra of MTPCs are much more complex than metal- loporphyrins, and several skeletal modes are found strongly coupled to the phenyl vibrations. The relationship between the Raman/IR frequencies and the structures of TPC ring is in-vestigated. It is found that the vibrations involving the Cα^I Cα^I stretch and CαCm stretchare sensitive to the size of corrole core. In particular, the frequency of v5, which is assigned to Cα^I Cα^I stretch in coupling with the CαCm symmetric stretch, increases linearly with the decrease of the corrole core-sizes and may be used as a mark band to evaluate the structural change of the metallocorroles.

Lifetime of metal rubber isolator with different vibration amplitudes

The lifetime of metal rubber isolator and its characteristics during lifetime experiment were studied. The stepped-up test principle was adopted to study the lifetime of resonant frequency, the breakage form of metal rubber isolator was obtained, and the relation between the energy dissipation, resonant frequency and stiffness was obtained in (available) lifetime of the isolator. Furthermore, the reason for the changes of properties of metal rubber isolator was analyzed with contact model of metal rubber material. The results show that if the resonant amplitude is large, the stiffness of metal rubber isolator will be kept steadily for a long time, its resonant frequency will be stable and the effective working time in the protecting area will be long. The lifetime of metal rubber isolator is more than 1376 h in the experiment. The main failure forms of metal rubber isolator are accumulative wear and breaking of metal wires and spirals. In protecting area the metal rubber isolator can work effectively for a long time, and the effective working time depends on the concrete working condition.

Structures and Stability of Metal Amidoboranes (MAB): Density Functional Calculations

Molecule geometry structures, frequencies, and energetic stabilities of ammonia borane （AB, NH3BH3 ） and metal amidoboranes （MAB, MNH2BH3）, formed by substituting H atom in AB with one of main group metal atoms, have been investigated by density-functional theory and optimized at the B3LYP levels with 6-311G＋＋ （3dr, 3pd） basic set. Their structural parameters and infrared spectrum characteristic peaks have been predicted, which should be the criterion of a successfully synthesized material. Several parameters such as binding energies, vibrational frequencies, and the energy gaps between the HOMO and the LUMO have been adopted to characterize and evaluate their structure stabilities. It is also found that the binding energies and HOMO-LUMO energy gaps of the MAB obviously change with the substitution of the atoms. MgAB has the lowest binding energy and is easier to decompose than any other substitutional structures under same conditions, while CaAB has the highest chemical activity.

Identification on rock and soil parameters for vibration drilling rock in metal mine based on fuzzy least square support vector machine

A single freedom degree model of drilling bit-rock was established according to the vibration mechanism and its dynamic characteristics. Moreover, a novel identification method of rock and soil parameters for vibration drilling based on the fuzzy least squares(FLS)-support vector machine(SVM) was developed, in which the fuzzy membership function was set by using linear distance, and its parameters, such as penalty factor and kernel parameter, were optimized by using adaptive genetic algorithm. And FLS-SVM identification on rock and soil parameters for vibration drilling was made by changing the input/output data from single freedom degree model of drilling bit-rock. The results of identification simulation and resonance column experiment show that relative error of natural frequency for some hard sand from identification simulation and resonance column experiment is 1.1% and the identification precision based on the fuzzy least squares-support vector machine is high.

Development of Integrated Precision Vibration-Assisted Micro-Engraving System

A novel precision vibration-assisted micro-engraving system was developed by the integration of fast tool servo and ultrasonic elliptical vibration system, in which the flexure hinge was designed to avoid backlash and PID control algorithm was established to guarantee specific precision. Apart from experimental validation of the performance of the system, various micro-V-grooves cutting experiments on aluminum alloy, ferrous material and hard cutting material were performed, in which Kistler force sensor was used to measure cutting force. Through experiments, it was clear that the vibration-assisted micro-engraving system can ensure good quality of micro-V-grooves and reduce cutting force by about 60% compared with traditional removal process without ultrasonic vibration.

红外监测技术在强度试验中的应用研究

本文采用高精度红外热像仪实时监测金属元件在静力拉伸试验和振动疲劳试验过程中材料表面温度变化,结合损伤和破坏的物理过程,对试验结果进行分析。分析表明,通过红外监测金属在载荷试验过程中表面温度变化情况,可以成为了解金属裂纹萌生、扩展等过程比较有效的无损监测手段。

Ultrasonic-assisted plastic flow in a Zr-based metallic glass

Ultrasonic vibration can be used for the micro-molding of metallic glasses(MGs)due to stress-softening and fast surface-diffusion effects.However,the structural rearrangement under ultrasonic vibration and its impact on the mechanical response of metallic glasses remain a puzzle.In this work,the plastic flow of the Zr35Ti30Cu8.25Be26.75 metallic glass with the applied ultrasonic-vibration energy of 140 J was investigated by nanoindentation.Both Kelvin and Maxwell-Voigt models have been adopted to analyze the structural evolution during the creep deformation.The increase of the characteristic relaxation time and the peak intensity of relaxation spectra can be found in the sample after ultrasonic vibration.It effectively improves the activation energy of atomic diffusion during the glass transition(Eg)and the growth of the crystal nucleus(Ep).A more homogenous plastic deformation with a weak loading-rate sensitivity of stress exponent is observed in the ultrasonic-vibrated sample,which coincides with the low pile-up and penetration depth as shown in the cross profile of indents.The structural rearrangement under resonance actuation demonstrated in this work might help us better understand the defect-activation mechanism for the plastic flow of amorphous systems.

Experimental investigation on shape memory alloy metal rubber

Shape memory alloy metal rubber(SMAMR)is a novel intelligent elastic damping material which can realize the integration of structure and function.The investigations on the anisotropic mechanical characteristics which depended on shaping craft and working temperature were conducted by quasi-static tests.Comparative experiments indicated that the heat setting temperature affect the elastic modulus non-monotonously but has little effect on the loss factor of SMAMR in both martensite and austenite phases.With the increase of the heat setting time,the elastic modulus of SMAMR monotonously decreases and the reduction of loss factor is unobvious.With the present shaping craft,SMAMR exhibits the anisotropy in moulding and non-moulding directions,which is affected by the heat setting process and working temperature.It was proved that the mechanical properties have approximately linear relationship with temperature during the phase transition process.Due to its temperature-dependent mechanical properties,SMAMR that experiences the heat setting procedure is expected to be used in active vibration control systems with varying temperature-dependent stiffness and damping coefficients to provide superior vibration control performance.

Ultrasonic-assisted rapid cold welding of bulk metallic glasses

Glass-forming ability is a long-standing concern in the field of metallic glasses(MGs),which greatly limits their maximum casting size and extensive applications.In this work,we report an ultrasonic-assisted rapid cold welding of bulk MGs without using any additives.MGs with various compositions are welded together under a 20,000-Hz highfrequency ultrasonic vibration without losing their amorphous nature.The ultrasonic technology offers the advantages of rapid bonding(<1 s)at low temperature(near room temperature)and low stress(<1 MPa).According to the phenomenon observed in the experiment,the activated fresh atoms diffuse through the broken channel port under continuous rupture of the oxide layer,and the ultrasonic vibration accelerates the atomic-diffusion process.Finally,stable bonding of the MG interface is realized.This universal ultrasonic-assisted welding process can realize the composition design of dissimilar MGs as well as tuning of new materials with new performance.