Applied Mechanics and Materials Vols. 217-219

Abstract: To improve the existing methods of identifying the key quality characteristics in multistage manufacturing process, the partial least squares regression (PLSR) method is combined with the state space model that a new method of identifying the key quality characteristics in multistage manufacturing process based on PLSR is proposed. According to the feature of multistage manufacturing process, the state space model is introduced to build the key quality characteristics identifying model for multistage manufacturing process, using the PLSR method to solve the problem of the quality characteristics such as multicollinearity, do model analyzing and identify the key quality characteristics. At last, the cigarette production process is presented as an example to introduce the application of this method. The result shows that this method can not only identify the key quality characteristics in multistage manufacturing process, but also establish the model of output quality effecting of all levels on the final product quality and its quality characteristics relationship, which reflect the structure of the multistage manufacturing process and causal relationship between quality characteristics at all process levels, provide the basis for quality analysis and control in multistage manufacturing process.

Abstract: Combining mind evolutionary algorithm with rough set and neural network, this paper proposed a rough set neural network based on MEA for transformer fault diagnosis. Rough set attribute reduction as the front-processor of neural network diagnostic device, and using MEA to search rough set discrete breakpoints and optimize neural network weights and thresholds, it avoided complex manual trial of the conventional rough set attribute reduction and slow convergence speed and low precision of BP neural network, then faster convergence to the global optimum solution and improves the diagnosis speed and accuracy. Simulation results show that this method is effective.

Abstract: The flow past 3D rigid cavity is a common structure on the surface of the underwater vehicle. The hydrodynamic noise generated by the structure has attracted considerable attention in recent years. Based on LES-Lighthill equivalent sources method, a 3D cavity is analyzed in this paper, when the Mach number is 0.0048. The hydrodynamic noise and the radiated mechanism of 3D cavity are investigated from the correlation between fluctuating pressure and frequency, the near-field sound pressure intensity, and the propagation directivity. It is found that the hydrodynamic noise is supported by the low frequency range, and fluctuating pressure of the trailing-edge is the largest, which is the main dipole source.

Abstract: The model of ultrasonic testing system kinematics was established, and ultrasonic testing of the scroll-type profile was come out. Based on reverse engineering (RE) techniques, the 3D model of actual parts was reconstruction. And then, the semitrailer 3D image about the position of lacuna was revealed in the model.Consequently the characteristics of lacuna were selected according to class. In finally, the rank identification method was adapted to recognize lacuna simply. Once this method is applied successfully in practice, the product quality and reliability of scroll compressor is improved, and the theoretical and practical support for full inspection of the product is provided.

Abstract: The traditional manufacturing cost-tolerance function is improved from the point of view of the time value of money, and this makes manufacturing cost in tolerances design more actual. A comprehensive mathematic model is constructed for the concurrent tolerance optimal design based on the time value of manufacture-quality loss cost. Purpose of the establishment of the model is equivalent calculation for cost-tolerance function and quality loss function of different time points, so as to make them calculated in the same time point, and concurrent tolerance optimal design is achieved. This modified model’s validity is proven by an illustrative example.

Abstract: Inkjet characters and graphics quality are impacted by rough and wavy exterior appearing along the line edge caused by feather and penetration phenomena. In order to deliberate whether only positive line attributes measurement was adequate to detect the output characteristic of an inkjet printing system, negative line quality survey was involved in. The attributes such as line width, contrast and blurriness etc. of negative lines in vertical and horizon direction together with positive lines were measured and analyzed though comparison according to ISO 13660 standard. Output characteristics of all kinds of lines were further summarized and detected in terms of attribute correlations of positive lines presented in existing study. Results show that when negative and positive lines are considered altogether the correlations among lines in different direction turn complex, which are distinguished with the simple correlativity in positive line quality detection.

Abstract: A new nonparametric multivariate control chart, based on a spatial-sign test and integrating the directional information from processes with the exponentially weighted moving average (EWMA) scheme, is developed for monitoring the mean of a univariate autocorrelated process. Simulation studies show that it has robustness in in-control (IC) performance, and it is more sensitive to the small and moderate mean shifts for non-normality underlying process than other existing multivariate chart methods.

Abstract: The main research of this paper is the influence of the main control circuit of WEDM-HS' pulse power on wire-cutting processing efficiency,make design improvement for the main control circuit of WEDM-HS' pulse power, put forward the corresponding countermeasures and solutions to the problems that the pulse power supply output current waveform is not steep along the before and after and it difficult to take digital adjustment in pulse width and interval.

Abstract: We designed an in-situ detection system suitable for Shanghai Synchrotron Radiation Facility. The system integrates remote control, temperature control, high-precision servo control and tension control technology, and can dynamically track the microstructure evolution of PAN precursor in the pre-oxidation and carbonization process using SAXS technology. The system has been put into use at the beam line BL16B1 at Shanghai Synchrotron Radiation Facility to investigate the structural evolution of PAN fibers with different drafting tension, temperature and atmosphere.

Abstract: This paper improves the simple genetic algorithm and combines genetic algorithm with BP algorithm to the wavelet neural network in the power transformer fault diagnosis by dissolved gas-in-oil analysis, Simulation result shows the problem was solved that wavelet network settles into local small extremum so easily that the network surging will increase and the network will not be convergent if the initialization is unreasonable, and overcomes the shortcoming that the speed is too slow if use genetic algorithm to train neural network independently.