Xiao Peng Li

Diagnosis of Local Fault and Identification of Transient Fault Force in Rotating Machinery

Model based fault identification techniques can be used to diagnose local faults in rotating machinery; the equivalent loads that represent fault forces can be used to identify the fault location. But in some cases the equivalent loads smeared over many nodes, and make it hard to identify accurate fault location and transient fault force. In this paper, the fault location is identified using least squares fitting approach by the system’s vibration shape when the fault signal is periodic or quasi-periodic. And after the fault location is ascertained, the transient fault forces can be identified by transient residual vibration using simple matrix multiplications and additions. Numerical simulations and experiment on rotor to stator rub are used to test the method, which proved the efficiency of the method.

Simulation of Fatigue Failure of Rail Joint Bolts by FEA

It is well known that the fatigue failure of bolts can affect the performance of rail joint and the safety of train running. In this work, the influence of the bolt torque and radius of rounded root of rail bolt on the fatigue strength of the rail bolt are studied by Finite Element Contact Analysis method. And the influence effects of the wheel impact and temperature force of the rail caused by temperature changed on bolt failure are studied. The results indicate that properly torque and increasing the radius of rounded root rail bolt can reduce the stress concentration at the root of rail bolt and this will improves the fatigue strength and the working life of the rail bolt and rail joint. The repeated temperature force of the rail and wheel impact force are playing an important role in the influencing factors on fatigue failure of the rail joint bolts. Due to this, the two bolts near the rail joints will to be fatigue failure almost earlier than others. That is one of the reasons why the bolts should be preloaded or replaced regularly.

New Developments of Product Design Methodology

Design and R&D (Research and Development) of products play an important role in development and competitiveness of enterprise. How to do the works better We think that most advanced product design methodology should be used on design, research and development of products. So-called most advanced product design methodology is that based on “the Scientific Outlook on Development” that we set up recent years. New developments of product design methodology include: At first it has been classified that more than seventy theories and methods proposed by domestic and overseas scholars in recent 100 years; QCTES was instead of IQCTES including six requirements of product design; traditional design stages were replaced with four new stages including investigation, planning, implement and inspection; green design was replaced with harmonious design; traditional design method was replaced with deep-layer design method; concept and connotation of product top-layer design were proposed; more detailed contents of product systematic design were advanced; formulas of complete system and product design quality, and connection equation between design objective, design content and design method were submitted. We got good effects to apply above product design methodology on many product designs recent years.

Theoretical Research and Experiment of Vibration Friction on Vibratory Compaction Experiment System

Friction under vibration condition presents extremely different complex characteristics from that of the conventional state. Practice shows that machine power rises obviously with the significant decrease of the fiction. However, occurrence mechanism of the vibration is not fully studied or revealed; therefore, how to further develop the benefits of vibration, there is no concrete and clear measures yet. From this actual situation, this work want to reveal the characters of nonlinear dynamic of the vibration friction, analyze the relationship between vibration and friction, discuss the impact of vibration’s parameters on the friction mechanism, Theoretical study and experimental verification were conducted to improve the work efficiency of the related equipments with the benefits of the vibration friction.

Fuzzy Synthesized Evaluation of Product Quality of Machine Tool Based on Harmonious Design Method

In this work, it is presented and studied that the harmonious of product function with capability, harmonious of product with product, harmonious of product with people, with technology, with society environment, with entironment from the view of entironment, society, economy, science, politics, culture and legal point in the design process. And the quality verification and evaluation methods are studied to enhance the design quality more effectively. And that, all the studied contents is named harmonious design method. One machine tool is used as an example to explain the method with design quality evaluated by fuzzy synthesized evaluation method from function, structure capability, working capability and craftwork capability factors. The grade and disparity of design quality are obtained through the evaluation results, then design project could be modified based on it, and it is very useful to improve product quality and to enhance performance-price ratio and market competitive ability.

RESEARCH ON PARAMETRIC SIMULATION TECHNOLOGY BASED ON COMPLICATED MECHANISM DESIGN

A new method is proposed, which is the core of parametric simulation based on complicated mechanism design. Furthermore, the connotation of parametric simulation is affirmed and the flow of parametric simulation based on complicated mechanism design is put forward. At last, taking a parallel mechanism as example, the technology of parametric simulation proposed is applied to the simulation study used ADAMS, which consist of analyzing mechanism, parametric modeling, creating GUI, creating menu and parametric simulation. The practice indicates that the method is effectual.Copyright

Investigating Morphology Evolution of Damage by a Cellular Automaton Modelling

A two-dimensional cellular automaton (CA) model is developed to simulate damage and fracture morphology evolution on the mesoscale in materials. The plastic convection of damage is mapped onto the CA lattice, and initiation, propagation and coalescence of damage are simulated with a local rule-based scheme of a probability cellular automaton. The model includes known physical distinctions of fracture behavior between microcracks and microvoids, and they are characterized by modifying the probability rule of the cellular automaton. The simulations provide visual insight to understand how those physical processes dynamically progress and they affect the damage evolution in materials. The modeling can be used to link micromechanical models to continuum damage models.

Structural design and kinematic analysis of moving mechanism of insulator inspection robot

The insulator is a part of high-voltage power transmission lines. The security and reliability of power system is mainly determined by safe working of insulator. Moving mechanism of insulator inspection robot is developed to inspect potential risk and operating status of insulator, which has important application in power engineering. Considering the working condition of insulator and mobile program of existing inspection robot, a novel foot-simulated moving mechanism of insulator inspection robot is proposed. Mobile program and structural configuration are determined, structural parameters are designed and kinematics analysis are completed. Finally, a 3D virtual prototyping of the moving mechanism is built with Solidworks, the moving process on insulator string of the mechanism is simulated with Adams, kinematic performances are calculated by simulating. The simulation results verify structural rationality of the moving mechanism and correctness of kinematic analysis proposed in this paper.

Moving Mechanism Design and Analysis of Suspension Insulator Inspection Robot

To drive synchronously and simply control system of insulator inspection robot, a single-driving moving mechanism of suspension insulator inspection robot is designed. The parallel transmission mechanism is designed to drive two sets of impeller shafts synchronously by single motor, which achieves synchronizing movement. Analysis and simulation are completed to verify structural parameters and kinematic performance of the moving mechanism. It is also discussed that the application of differential drive systems to obtain synchronizations of the driving branches and adjustment of structural errors of insulator strings.

Topological Representation and Operation of Motion Space Exchange Reconfiguration of Metamorphic Mechanisms

The paper presents a topological representation of mechanical chains based on proposed joint-axis matrix based on our previous study, and motion space exchange reconfiguration metamorphic processes of multi-loop mechanisms are operated by the matrix. The matrix operations of metamorphic process are performed by replacing the joint of planar mechanisms with passive mobility joint to form the passive mobility mechanisms firstly, and then changing the orientation of metamorphic joint of the passive mobility planar mechanisms to transform the configuration of the mechanisms from planar to spatial one. The matrix operations of 8-link multi-loop mechanism are illustrated to show the motion space exchange reconfiguration processes.