Papers by Author: Yi Min Zhang

Abstract: 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.

Abstract: Parameter uncertainty of general systems is inherent in most engineering problems. Based on the regularity of oil whip and resonance for rotor system, the reliability problem of rotor system with oil whip and resonance is studied by applying random perturbation technology and reliability theory considering the correlation of the multi-order natural frequency. The reliability mode and the failure probability of rotor systems are defined. The second-order joint failure probability is obtained by using the numerical integration method. The presented method provided the theoretic basis for the reliability design of the rotor system. A numerical example demonstrated that the proposed method is effective.

Abstract: 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.

Abstract: A new way, which is used to analysis the path contribution, is presented for the vibration transfer path systems considering the interact of vibration source, transfer path and receiver. It is that the path contribution is evaluated using the path transfer probability. According to the dynamic characteristics of vibration systems, the new concept of path transfer probability is given. Based on the generalized probabilistic perturbation method and the reliability theory, the computational approach for path transfer probability with uncertain physics and geometry factors in time range are presented. The transfer probability of vibration transfer path systems with translational and rotational motions is analyzed and calculated via a numerical example, which shows that the proposed method is feasible.

Abstract: Based on the reliability-based optimization design theory, the reliability sensitivity technique and the robust design method, the reliability-based robust design of rubbing rotor system is extensively discussed and a numerical method for reliability-based robust design is proposed. The reliability sensitivity is added to the reliability-based optimization design model and the reliability-based robust design is described as a multi-objection optimization. On the condition of known first four moments of basic random variables, the respective program can be used to obtain the reliability-based robust design information of rubbing rotor system accurately and quickly using the fourth moment technique. According to the numerical results, the approach proposed is a convenient and practical reliability-based roust design method.

Abstract: By assuming that the random parameters of a continuum structure obey the normal distribution, this paper utilized “normrnd” function in Matlab software to generate pseudo random numbers, analyzed structural stress by using finite element method, conducted topology optimization by using k nearest neighbor (KNN) method, and as such, the continuum structure has been stochastic topology optimized. The paper put forward the concept of “stochastic topology optimization”. Numerical examples are given. The results show that the stochastic topology optimization of continuum structure with random parameters is necessary.

Abstract: The KNN method is extracted from the technique of pattern recognition for the continuum structure topology optimization design with information functional materials. Original design region is taken as initial sample space, and continuum structure's units are regarded as samples. Unit stress and displacement sensitivity are utilized as feature vector to describe sample, and the feature vectors' Euclidean distance is considered as the recognition standard to classify all the samples. One FEM package is utilized to process the entire optimization. Finally, the topology optimization result is obtained. Several examples are verified under different situations. The results indicate that the KNN method is feasible.

Abstract: The characteristic of vibration and noise of an automobile has become an important guide line to evaluate an automobile during the development of manufacturing and comfort of automobiles. In this study, finite element modal analysis was used to extract the acoustic resonant frequency and acoustic modal modes. The results show that the influence of vehicle seats on the acoustic modality should be considered in the acoustic design of vehicle interior cavum. Higher acoustic pressure areas for lower acoustic modalities mainly lie at the anterior/posterior ends or middle of the vehicle interior cavum.

Abstract: Based on the reliability theory, the probability perturbation technique, the reliability sensitivity technique and robust design were employed to discuss the reliability-based robust optimization problem of structure system with multiple failure modes. By means of the probability network evaluation technique (PNET), the representative failure modes of structure system were defined. Then, the reliability and the reliability sensitivity of the system were obtained. By integrating the reliability sensitivity into the reliability-based optimization design model, the robust reliability design of structure system was discussed. According to the numerical results, the method proposed is validated to be practical and effective.

Abstract: This paper presents a method for tolerance design of four-bar function generating mechanisms with joint clearances using Taguchi method. Based on previous studies made by other researchers, we propose a model to quantify the effects of uncertain factors on the accuracy of four-bar function generating mechanisms. Taguchi’s approach is applied to select the optimal tolerance ranges for the design parameters of function generation mechanisms. Sensitivity maps are plotted to provide an insight to the effects of parameter errors on the performance variances of four-bar function generating mechanisms. To illustrate the efficiency of the proposed methodology, the tolerance design of a four-bar function generator with joint clearances is discussed.