Yun Nan Teng

Pedestal Looseness Fault Analysis of Overhanging Dual-Disc Rotor-Bearing

Looseness fault can occur in rotor part, bearing and pedestal for the vibration caused by alteration of operating craft and inappropriate installation. In the paper, a new pedestal looseness model is proposed by comprehensively considering the advantages and disadvantages of current models of pedestal looseness. By using nonlinear finite element method, the nonlinear characters of overhanging dual-disc rotor bearing for pedestal looseness fault are studied. The work has important significance on safe running and prolonging the life span of machines.

Failure Analysis and Reliability Evaluation of a Planetary Gear Box

With the qualities of smooth operation, high efficiency and small size, the planetary gear box was widely used in transmission field. In this paper, a 2-stage planetary gear box was studied. CAXA and Pro/E were used for modeling. The FEA analysis results were obtained by ANSYS, both the contact stress and the bending stress of the gear tooth root. The results showed that with the continuous action of cyclic loads, the excessive contact stress is the direct reason of the failure. Then, the system reliability evaluation was made, which can provide guidance for engineering practice.

Simulation on Vibration Friction Mechanism of Vibration Pile System

Vibratory pile drivers are widely used in mechanical industry field. In this paper, the nonlinear dynamic model of vibration friction pile-soil system considering the soil friction force is proposed. By numerical simulation, the dynamics characteristics of vibration friction for pile-soil system were obtained. The results showed that with the increasing of excitation amplitude and frequency, the displacement of the pile and frame are both increased.

Study on Vibration Friction Mechanism of Vibration Compaction System

The mechanism model of vibration compaction system was built. The vibration friction mechanism of vibratory compaction system was studied based on granular dynamics theory. The results show that the void ratio does a great impact on strength and compaction.

Study on Assessment Method and Statistical Distribution of Roundness Error

The active academic basic of the shape tolerance and shape error assessment is a geometrical problem which is based on the shape tolerance zone. The research puts forward the probability distribution of the statistical roundness error on the condition of the researching about roundness error of rotor parts and does experimental measurement and data collection. In order to prove that it complies with certain probability distribution law, the fitted roundness error should gain the statistical distribution result by using mathematical statistics.

Experimental Investigation of Characteristics of Vibratory Compaction System with Different Water Saturation

In this work, the numerical equation has been established to simulate the vibratory compaction system based on the hysteresis loop of Davidenkov and with the gap ignored between the piston and the materials, and the dynamical characteristics and influence of parameters on the vibration compaction effect were analyzed with different stiffness, damping, amplitude and mass with different water saturation. The two types of experiments were carried out to study the dynamical characteristics and validate the numerical analysis and simulation. The first type of experiments was done with the different exciting vibration amplitude. A second type of experiments was done with the different water saturation (3%, 8% and 17%) instead of the stiffness and damping. The numerical and experimental results show that the equivalent natural frequency and vibration amplitude of the system increased with the stiffness, exciting amplitude increased and damping decreased. The experimental results agree well with results from a theoretical model in general. The research results will be used in intelligent soil compaction in the future.

Investigation on Nonlinear Dynamics Characteristics of Vibration Friction System Based on Vibration Pile Driver

As a branch of Utilization of vibration, vibration friction is a type of the most valued applicable technology developed during the later part of the 20th century and still in rapid development now. Since the technology is closely associated with industrial and agricultural production, can create huge social and economical benefits for our society and provide excellent service for human beings, it becomes a necessary mechanism in human production and life. The theory of the vibrating machines has been developed and used widely in this field. In this paper, nonlinear dynamic characteristics of vibration friction system based on vibration pile driver were investigated. According to dynamics theory, the motion equation of vibration friction system was established. For further study of vibration friction mechanism and its application on vibrating machines, numerical simulation of vibration pile-soil system was made. Chaos was found in the process of motion. The conclusion of our research is that vibration can decrease rub and wears between vibrating body and materials and it is very important to prolong the working life of machines and their parts.

Comprehensive Evaluation for Generalized Product Quality Based on Fuzzy Entropy

With a view to improving product quality, the concept of generalized product quality is proposed and analyzed in depth to frame a comprehensive fuzzy evaluation system for generalized product quality, which includes all the constructional, operational and technological performance and function and takes account of the hierarchy and complexity of such an evaluation system. In the system the weighted value for each and every evaluation index is determined by combining entropy weight with subjective weight so as to make the evaluation more objective and scientific. Comparing with the method of comprehensive fuzzy evaluation, the evaluation system thus framed gets rid of the empirical subjectivity in determining index weight, thus enhancing the dependability of the weight, as a result, such an evaluation will be more reliable.

Research on Vibration Test Method of the Whole NC Machine Tool

Vibration test of the whole machine has become an important measure to solve vibration problem of NC machine tool, because it can evaluate anti-vibration performance and check the validity of vibration analysis. In the paper, on basis of confirming the vibration test contents for NC machine tool, the vibration test method and flow of the whole machine are proposed from the need of engineering, which include planning experiment instruments, confirming test contents, putting up test system, vibration test, analyzing experiment data etc. At last, taking a NC boring machine which is built by Shenyang machine tool group as study case, the whole machine vibration test is done. The practice indicates that the method is effectual.

Bearing Parameter Optimization of a Compressor Rotor System Based on Orthogonal Experimental Design

A Low-pressure cylinder rotor of certain large centrifugal compressor units was studied by combing orthogonal experiments and finite element method. The effect of bearing parameters (length-diameter ratio, clearance ratio, dynamic viscosity of lubricating oil and preload) to bearing-rotor system stability and journal vibration was evaluated and optimum bearing parameters were determined. The significant and non-significant factors influencing on system stability and journal vibration were determined by variance analysis and F test. These conclusions will provide guidance to compressor rotor system design.