Zhao Hui Ren

The Estimation of Barrel-Rifle Surface Wear Based on Fractal Theory

In this paper, the theory of fractal geometry was used to study the barrel-rifle surface topography and correlation dimension method was adopted to calculate the fractal dimensions of the projectile worn marks shot from the barrels with different worn. The study showed that the different wears of barrel-rifle surface resulted in different fractal dimensions of the projectile wear surface and there was a correlation between the fractal dimensions of the projectile wear surface and the change of the barrel rifle surface. Therefore, through the rifle marks on the projectiles, not only the wear of the barrel’s internal surface can be analyzed, but the gun life also can be further estimated. The paper provided a new tool for analyzing the barrel-rifle surface wear.

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.

Numerical Simulation and Experimental Research on Pedestal Looseness of a Rotor System

The mechanical model of looseness of fastening bolt on the bearing pedestal is set up based on the project practice. Using the nonlinear oil-film model put forward by Adiletta, the dynamic characteristics were investigated by numerical Runge-Kutta method. At last, the experiment is performed to investigate the pedestal looseness by a test rig and the fault signals are analyzed by the spectrum cascade and reassigned wavelet scalogram. Numerical simulation and experiment all show that system motion state changes frequently with the increase of the rotating speed. And the experimental results coincide with the simulation results.Copyright

Study on Fault Diagnosis of Rotating Machinery Based on Lyapunov Dimension and Exponent Energy Spectrum

In connection with the nonlinear dynamic characteristics shown from the performance of fault rotating mechanical system, the authors propose the analysis method of Lyapunov dimension and exponent energy Spectrum to the signal feature of mechanical fault. Using theory of phase space reconstruction, simulating fault signal of rotating machine is reconstructed. In order to reconstruct the phase space which can be adequately reflect the movement characteristics of the system, the time delay and embedding dimension are discussed emphatically, on this basis, calculated the Lyapunov dimension and exponential energy spectrum. From the analysis and calculation on simulation of different fault signals, it shows that under different rotating machinery fault conditions, its Lyapunov dimension and exponential energy are significantly different, which verifies that this two nonlinear feature quantities is effective parameters for fault information

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.

A Heuristic Genetic Algorithm for Continuous Attribute Discretization in Rough Set Theory

Continuous attribute discretization based on rough set is to got possibly minimum number of cuts, and at the same time it should not weaken the indiscernibility ability of the original decision system. In order to obtain the optimal cut set of the continuous attribute system, based on research the choice of candidate cut set, this paper presents a heuristic genetic algorithm for continuous attribute discretization to decision tables. In this algorithm making the importance of the continuous cut as heuristic message, a new operator is constructed to not only maintain the discernibility of the cuts selected, but also improve local search ability of the algorithm. Compared the performance of this method with the others’, this method is proved effective and superiority.

Research on Optimization Model Based on House of Quality Fuzzy Theory in Industrial Environment

In this paper, under House of Quality(HOQ) Fuzzy Theory, taking product planning House of Quality(HOQ) as an example, systematically considers fuzzy auto-correlation matrix of engineering properties influence on engineering properties target value and development cost, by definition some concepts, such as engineering properties plan improvement level, practice improvement level, fuzzy planning cost coefficient and fuzzy actual cost coefficient, establish properties target value optimization model based on House of Quality(HOQ) Fuzzy Theory, and validate this method by a case study.

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.

A Method for Completeness Testing of Dimensioning in 2D Drawing

Dimensioning work is a considerably important link in the whole Engineering Drawing. For existing completeness testing of dimensioning, correct conclusion can not be drawn in case of multi-closed dimension. This paper mainly discusses the ways how to automatically check up the deficiency and redundancy of the dimensions. This paper presents a new and effective algorithm to test whether the dimensions are redundant or insufficient by means of the graph theory and intelligent search. The dimensions are transformed to non-directed graph, then detects whether they are redundant or insufficient by traversing adjacent matrix of the non-directed graph. The deficiency and redundancy of dimension for multi-views of engineering drawing can be corrected by this algorithm.

Analysis on Stress Characteristics of Rolling Body of Rolling Dryer

Rolling dryer is one kind of dryer device with large output. The characteristic of rolling body has great influence on the output of dryer. In the paper, with the finite element method, the stress distribution of body, bolt hole, man hole and modes of rolling body are obtained by static stress and modal analysis and study of acting loads on rolling body. The results can help to enhance the efficiency of rolling dryer and provide corresponding theoretical supports for the design and manufacture of the machine.