Yi Min Zhang

Reliability-Based Sensitivity Design of Gear Pairs with Non-Gaussian Random Parameters

Based on reliability design theory, by using the Edgeworth series method, and the sensitivity analysis method, the reliability sensitivity of the cylindrical gear pairs with non-Gaussian random parameters are extensively discussed and a numerical method for reliability sensitivity design is presented. The variation regularities of reliability sensitivity are obtained and the effects of design parameters on reliability of the cylindrical gear pairs are studied. The presented method provides the theoretic basis for reliability design of cylindrical gear pairs.

Research on Active Suspension System Based on BP and RBF Network Algorithm

A six degrees of freedom half body vehicle suspension system is presented in the paper .The Back Propagation neural network algorithm and the Radial-Basis Function network algorithm is adopted to control the suspension system. With the aid of software Matlab/Simulink , the simulation model is obtained. A great deal of simulation work is done. Simulation results demonstrate that both the designed radius basis function neural network and the back propagation neural network work well for the proposed vehicle suspension model in the paper .

Dynamic Reliability Sensitivity Analysis of Torsion Bar

In this paper, the variation rules of strength, load, reliability and failure rate of mechanical components are studied with time, and a state equation model for dynamic reliability of mechanical components is established under random load. Meanwhile, reliability index is obtained by using Second moment method and perturbation method. Based on the reliability design theory and sensitivity analysis method, torsion-bar is taken as an example, and the dynamic reliability sensitivity of torsion-bar is extensively discussed and a computing method is presented for dynamic reliability sensitivity design. The variation rules of dynamic reliability sensitivity are obtained and the effects of design parameters on reliability of torsion-bar are studied. As a result, the proposed method provides theoretical basis for reliability design of torsion bar.

Frequency Reliability Sensitivity and Robust Analysis for the Random Axial Vibration of Rod Systems

The paper is concerned with the frequency reliability sensitivity and related robust analysis problem for the random continuous vibration structure systems. Reliability analysis based on frequency is necessary for reliability problems of uncertain vibration structure systems. With the criterion that the absolute value of the difference between the natural frequency and forcing frequency, the reliability mode and the safety probability of the random systems are defined, and then The frequency sensitivity analysis method is quested by using the random perturbation technique, the reliability theory and sensitivity approach. Furthermore, the frequency reliability-based robust method of the random dynamic structural system was obtained by the robust and the optimization technology on the basis of frequency reliability and sensitivity design, which helped designers to establish acceptable parameter values and to determine the fluctuations of the parameters for the safe operations. Moreover, a numerical example is provided to demonstrate the effectiveness and accuracy of the proposed method. This study established theory basis for sensitivity and robust evaluation.

Reliability of Vibration Transfer Path Systems

Based on the matrix calculus, the generalized second moment technique and the stochastic finite element theory, the effective approach for the transfer reliability of vibration transfer path systems was presented. The transfer reliability of vibration transfer path systems with uncertain path parameters including mass and stiffness was analyzed theoretically and computed numerically, and the correlated mathematical expressions were obtained. Thus, it provides the theoretical foundation for the dynamic design of vibration systems in practical project, so that most uncertain factors can be considered to solve the random problems for vibration transfer path systems.

Global Sensitivity of Random Parameters in Vibration Transfer Path Systems

Based on the Sobol’ theory, Hamma and Saltelli indicator system, the path parameters were divided into the different subsets for the vibration transfer path systems with random paths in this paper. The object function was constructed and decomposed, thus the global sensitivity based on variances was formed. The first-order and total sensitivities of various parameter subsets were calculated using Monte-Carlo simulation method combined with Latin hypercube sampling technique. Through the analysis example, the way is feasible to analyze the interaction of paths or path parameters in the vibration transfer path systems with uncertainty.

Reliability Analysis of Alumina-Based Ceramic Cutting Tool's Wear Life by Saddle Point Approximation

Under continuous cutting conditions, the reliability of alumina-based ceramic cutting tools wear life with abrasion wear was discussed extensively. An ultimate state equation of alumina-based ceramic cutting tools wear life was proposed according to stress-strength interference theory. Based on the premise that the probability distribution of random parameters has been known, the fracture toughness KIC and the hardness H which obey Weibull distribution were transformed into normal distribution by means of the equivalent normal distribution method, and then the reliability of alumina-based ceramic cutting tools wear life was analyzed by saddle point approximation method. The probability density function and cumulative distribution function of the ultimate state equation were accurately and quickly obtained by way of saddle point approximation, as a result, the saddle point approximation method was proved accurate with high computing speed in comparison with the Monte-Carlo method. Therefore, the application of the saddle point approximation method developed the reliability analysis theory of alumina-based ceramic cutting tools wear life.

Random Response Analysis of Vibration Transfer Path Systems with Translational and Rotational Motions

This paper based on the generalized probabilistic perturbation finite element method solves the random response analysis problem of vibration transfer path systems with translational and rotational motions. The effective random response analysis approaches are achieved using Kronecker algebra, matrix calculus, generalized second moment technique of vector-valued functions and matrix-valued functions. For the vibration transfer path system with multi-dimensional paths, the random response is described correctly and expressly in time domain as uncertain factors, which include mass, damping, stiffness and position, are considered. The mathematical expressions of the first order and second order moments for the random vibration response of vibration transfer path are obtained. According to the corresponding numerical example, the results of calculation are consistent with the results of Monte-Carlo simulation, which shows the method is feasible theoretically.

Frequency Reliability-Based Robust Design of the Random Dynamic Structural Systems

The frequency reliability.method of avoiding resonance is proposed by the mechanical dynamics, stochastic finite element method, the reliability theory in the paper. Furthermore, the frequency reliability sensitivity method is presented based on the frequency reliability research, and the frequency reliability-based robust method is obtained by the robust and the optimization technology on the basis of frequency reliability and sensitivity design, which help designers to establish acceptable parameter values and to determine the fluctuations of the parameters for the safe operations. Moreover a numerical example is provided, the frequency reliability robust numerical results are obtained, which are in agreement with practice and demonstrate the effectiveness and accuracy of the proposed method.

Frequency Reliability and Sensitivity Analysis on the Rotor System

Multispan rotor system(H858 compressor) is studied in this paper. Based on the rotor dynamic theory, complex rotor system is simplified reasonably, and finite element model is established using finite element software(MSC.Patran&Nastran). The natural frequencies are obtained in the condition of bending vibration, and the functions of frequencies and variables are matched on the basis of the artificial neural network (ANN) technique. With the criterion that the absolute value of the difference between the natural frequency and forcing frequency, the reliability mode and the systems safety probability are defined, then the frequency reliability sensitivity analysis method is presented. And the equations of the related sensitivity with respect to mean values and variances are mathematically expressed. The reliability and sensitivity of rotor system are analyzed, which demonstrate the effectiveness and accuracy of the proposed method.