Papers by Author: Jian Hua Wu

Abstract: This paper discusses an in-depth analysis of various encryption technologies, such as RSA, DES, SHA-1, improves DES algorithm and combines their advantages, then put forward a new communication security model based on various algorithms. Thus increasing the security of asynchronous network communication system.

Abstract: Residual stress field induced by laser shot peening (LSP) was simulated using Box-Behnken experimental design. Compressive residual stress field intensity (S) was introduced to estimate the effect of compressive residual stress field on fatigue performance. The effect of laser process parameters (such as laser shock wave peak pressure, spot diameter and peening number) on S was analyzed by response surface analysis (RSA), quadratic regression predicting model for S was established, and the rationality of that was verified. Finally, the optimal combination of laser process parameters oriented to anti-fatigue manufacture was optimized. The results indicated statistical analysis results agreed well with those of simulation, RSA for parameter optimization of LSP is feasible.

Abstract: Laser forming of a micro-structural element involves a complex thermoplastic process. Numerous efforts had been made on the mechanisms of laser forming for macro-size elements, such as temperature gradient mechanism, buckling mechanism and upsetting mechanism, etc. It is found that the three mechanisms cannot depict fully the process of deformation in the macro-size element forming, let alone meet the needs of the micro-size one. Considering the laser inducing thermal stresses with size factors differing from the conventional analysis, it is essential to reveal the mechanisms dominating the forming process to accurately control the bending angle of a tiny plate. By studying the thermal transfer and elastic-plastic deformation of micro-structural element laser forming, the forming mechanism is explained within the micro size. The finite element model for laser bending is constructed for simulation. The stimulation results are agreement with the experimental data.

Abstract: In order to obtain the total cutting energy and the ratios of the three parts of the total energy during cutting off the rubber, a test method was proposed and a test apparatus was constructed to perform the rubber cutting experiment. In the test, the friction force and the cutting force were obtained. Through the analysis of the test results, the friction work, the deformation energy, the surface fracture energy in cutting different thickness of the rubber were calculated. This work originally proposed a test method to acquire the friction force, the friction work between the cutter and workpiece during punching process.

Abstract: Predicting the precision of grinding process, especially correlating surface functionality generation to grinding conditions, would be of great significance to improve grinding accuracy of the end precision product. Huang developed a very promising revolutionary spectral data analysis technique based on the Hilbert transform. The concrete methods of the EMD, the local Hilbert spectrum are introduced. An artificial neural network (ANN) based on back propagation is developed to predict surface roughness Ra. An accelerometer is employed as in-process surface recognition sensor during grinding process to collect the vibration as input neurons. Changing the grinding condition, training and testing within the artificial neural networks to retrieve the weightings, the experimental results show that the proposed ANN surface recognition model is economical, efficient and the model has a high accuracy rate for predicting surface roughness.

Abstract: The surface roughness is evaluated by decomposing micro-errors from irregular surface image. The wave of surface is designated as signals including high-frequency, mid-frequency, and low-frequency signal, that denote roughness, waveness and the geometry shape error. Hilbert-Huang transform is a promising revolutionary technique for spectral data analysis, which is used to extract roughness from surface. It overcomes the imprecise result of the traditional surface roughness calculation and avoids the complication of the Wavelet analysis. Theory of Empirical Mode Decomposition (EMD) is given in the paper. This method is initially applied in picking up surface roughness, and it is proved to be of very high efficiency and simplicity.