Issues of Synthesis and Practical Evaluation of the Compensation Mode Error of a Two-Component Gyroscope

The paper introduces the results of studying the characteristics of various dynamically tuned gyroscopes operating in the mode of a variable rate sensor. Within the study, we determined the dependence of the dynamic error of the rate sensor on the amplitude and frequency of angular oscillations of the gyroscope body. We analyzed the methodological and hardware support for evaluating the dynamic error of a dynamically tuned gyroscope — the rate sensor in order to reduce its influence on the operational characteristics of the device. To experimentally research and practically evaluate the dynamic error of the dynamically tuned gyroscope — the rate sensor, we proposed a design of the rotary vibration test bench, developed requirements for it, and calculated its elastic-mass characteristics.

EXPERIMENTAL STUDY OF THE PERFORMANCE OF "DRY" SEALS IN THE PRESENCE OF ROTOR VIBRATION

The article presents the results of an experimental study of "dry" seals in the presence of rotary vibration. The descrip-tion of the dynamic stand measurement system is given. An assessment of the influence of vibration loads on leakage through the seal and an analysis of the influence of radial displacement and shaft misalignment on the operation of a "dry" seal are carried out. The analysis of the cause of the vibration defect is presented. The permissible values of the vibration amplitudes of the rotor of the gas pumping unit have been determined.

Analysis of Rotary Vibration of Rigid Friction Pipe Pile in Unsaturated Soil

Based on the mixture theory and previous work, the governing equation of the rotary vibration of rigid friction pipe pile in unsaturated soil is established. The analytical solution of this equation can be used to analyze the displacements and the complex stiffness of rotary vibration. The results show that the contribution to stiffness is as follows: solid < liquid < gas; and the contribution to rotational impedance is as follows: solid > liquid > gas. In addition, when the fluid permeability coefficient decreases, the stiffness decreases and the rotational impedance increases, but the influence is not obvious (especially the gas permeability coefficient). Four different kinds of degradation problems are also presented. Relevant conclusions can provide reference for engineering application.

Development of a Novel Three Degrees-of-Freedom Rotary Vibration-Assisted Micropolishing System Based on Piezoelectric Actuation

The limited degrees of freedom (DOF) and movement form of the compliant vibration-assisted processing device are inherent constraints of the polishing technique. In this paper, a concept of a 3-DOF rotary vibration-assisted micropolishing system (3D RVMS) is proposed and demonstrated. The 3-DOF means the proposed vibration-assisted polishing device (VPD) is driven by three piezo-electric (PZT) actuators. Compared with the current vibration-assisted polishing technology which generates a trajectory with orthogonal actuators or parallel actuators, a novel 3-DOF piezoelectrically actuated VPD was designed to enable the workpiece to move along the rotational direction. Meanwhile, the proposed VPD can deliver large processing stoke in mrad scale and can be operated at a flexible non-resonant mode. A matrix-based compliance modeling method was adopted for calculating the compliance and amplification ratio of the VPD. Additionally, the dynamic and static properties of the developed VPD were verified using finite element analysis. Then, the VPD was manufactured and experimentally tested to investigate its practical performance. Finally, various polished surfaces which used silicon carbide (SiC) ceramic as workpiece material were uniformly generated by the high-performance 3D RVMS. Compared with a nonvibration polishing system, surface roughness was clearly improved by introducing rotary vibration-assisted processing. Both the analysis and experiments verified the effectiveness of the present 3D RVMS for micro-machining surfaces.

Analysis on Current Technical Status and Development of Tumbler Screening Machines in China and Abroad

A multi-faceted introduction on current state and development trends of tumbler screening technology was proposed, which included that the origin and development of the tumbler screening machines, a comparison between tumbler screening machines and rotary vibration screens, the structure design and analysis, especially the screen mesh cleaning technology and specific machine applications. The status and development trends of tumbler screening machines in China and abroad especially in German were analyzed. The developing direction of future tumbler screening machines and the situation of Chinese businesses producing tumbler screening machines development were introduced.

Stress Analysis of Rotary Vibration of Rigid Friction Pile and Stress General Solution of Central Symmetry Plane Elastic Problem

The rotary vibration of rigid friction pile can be seen approximately as a central symmetry plane problem in elasticity. The stress general solution of central symmetry plane problem in elasticity can be constructed by technique such as the Laurent expansion of the volume force. This solution has some decoupling, generalized, and convergent properties, and it can be used in stress analysis of the rotary vibration of pile. The analysis results show that the maximum value of displacement will not occur at the edge of the pile and the assumption that pile cross section remains unchanged is no longer applicable, if the value of one dimensionless quantity, reflecting the angular frequency of the rotation, radius, and material properties of the pile, is larger than 1.84. Once the rotary vibration of rigid friction pile happens, the pile may lose its bearing capacity under the comprehensive effect of normal and shear stress of the pile-soil interface and it will be very difficult to recover.

Synthesis of Fine Co/ WC Composite and Application to Supersonic Plasma Spraying

Co/ WC composite powders (with 10 wt% content of Co) were synthesized by direct mechanical grinding in a rotary-vibration mill. The powders with different mill time were evaluated. WC and WC/Co composite coatings were prepared by supersonic plasma spraying. The results showed that the milled powders consist of composite particles that were formed in the first 2h of milling. Longer milling times improve the distribution of phases inside the composite particles. The formation of the composite particles involves sequential steps of deformation, fragmentation, cold welding, work hardening and piercing of particles of the hard phase in the soft phase. X-ray spectra of the sprayed coating are shown that only very weak W2C and Co6W6C peaks are observed. Compared with WC coating, the Co/ WC coating is denser, and less large pores within composite coating.