Papers by Keyword: Uniform Design

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Authors: Zhong Gan, Zhi Wei Qian, Yu Shan Xia
Abstract: This paper proposes a more accurate springback prediction method of ageing forming for 2124 aluminum alloy. In age forming of panels, pre-bending radius, aging time and wall thickness of panels are selected as three parameters, make use of uniform design to arrange experiment and obtain springback radius using ABAQUS simulation. By means of regression analysis, the data is processed to get the influence caused by parameters on springback radius. Regression and BP neural network forecasting method are used respectively to predict springback radius and maximum prediction error is less than 31%. Combination method based on BP neural network is adopted and this method gets the satisfying prediction results that prediction error is within 5%. So conclusion can be drawn that prediction accuracy of combination method is much better than that of regression and BP neural network forecasting.
Authors: De Liang Ren, Bo Liao, Changling Xu, Lianhai Hu, Fu Ren Xiao
Abstract: By using the mathematical uniform design, a new agglomerated flux for high speed and multi-arc submerged arc welding (SAW) has been developed in this paper, which performs excellently in welding process, and the effects of flux composition on the welding characteristics is analyzed as well. The mechanical tests show that the weld metal obtained in SAW with this flux exhibits high toughness at low temperature, and the other mechanical properties of the weld metal also satisfy the technical specifications for the West to East Pipeline Project in China. The microstructures of the weld metal are also examined. Both optical and TEM microphotoes demonstrate that the weld consists mainly of small-sized and uniformly distributed acicular ferrite. These microstructures can effectively prevent the initiation and propagation of micro cracks, resulting in high notch toughness of the weld metal at low temperature.
Authors: Yu Tao Yan, Zhi Li Sun, Guang Wei Hu
Abstract: The wear experimental project on main influencing factor with load, sliding speed, surface hardness and lubrication was instituted by the uniform design, the wear properties were investigated on a MMW-1 friction and wear tester. The predication formula for wear rate was defined. The wear rate predication model was established by the partial least squares based on the test data, the influencing degree on the main influencing factors was analyzed, the results show the influence on wear rate from big to small is in turn load, lubrication, surface hardness and sliding speed. The lubrication property improved is a handy valid path to decrease the wear rate. The check results show that it is a valid method by partial least squares to establish wear predication model based on test data.
Authors: Wen Li, You An Xiao
Abstract: An improved optimization method on the material mixture ratio of ship stern bearing is proposed. During the optimized experiment of ship stern bearing material mixture ratio, uniform design and partial least-squares regression are used to extract the regression function between the optimization object factors (including friction coefficient of the stern bearings, abrasion loss in unit time)which can evaluate the performance of ship stern bearing material mixture ratio and the other experimental factors(including the material mixture ratios of stern bearing components, stern bearing processing temperature).The total optimization object function is composed by the proper weighting to these obtained regression functions.The optimized material mixture ratio will be attained when the comprehensive evaluation index which is the value of the total optimization object function gets its optimum value. Through an analytical comparison with existing optimization method , the improved optimization method can greatly reduce testing times and the experimental cost, shorten the experiment period in the allowed precision range. Based on the experimental analysis of a technology simulation model of related ship stern bearing, it shows that the improved optimization method is practicable and effective.
Authors: Jie Song, Zhi Gang Song, Yi Jie Shen
Abstract: Pedestrian loads are affected by such uncertain parameters as walking step frequency, step length, dynamic load factors and phases of harmonic components, which lead to the uncertainties of structural response. A new method for calculation random response spectrum based on uniform design is introduced to reduce calculation work. A few representative samples of loads time histories are simulated using uniform design, and then the RMS acceleration response spectrums are obtained by dynamic time-history analysis of beam structures with different spans and damping ratios. The RMS acceleration response spectrums which have certain percentiles are obtained by reliability analysis based on response surface. Ultimately the general forms of RMS acceleration response spectrums are deduced from the analyses of sensitivities for damping ratio and span.
Authors: Jin Yang Xu, Qing Long An, Ming Chen
Abstract: This research is concerned with the analytical and experimental study on milling of 2024-T351 aluminum alloy with TiAlN coated carbide cutting tools in both low-speed machining and high-speed machining. The results are analyzed in terms of surface roughness and residual stresses of the workpiece. Surface roughness studies indicate that in high-speed milling of 2024-T351 aluminum alloy the surface roughness can maintain a lower value and the workpiece can obtain excellent surface quality compared to the low-speed machining. The high-speed milling was found to be able to enhance the original residual stresses of the workpiece; while the low-speed milling may weaken or undermine the original residual stresses, or even transform the initial compressive stresses into the tensile stresses.
Authors: Bin Nie, Jian Qiang Du, Ri Yue Yu, Yu Hui Liu, Guo Liang Xu, Yue Sheng Wang, Li Ping Huang
Abstract: Traditional Chinese Medicine have the secret is dosage,the Traditional Chinese Medical clinical therapeutic effect key is prescription’ dosage. A majority of Chinese medicinal herbs are generally crude plants with fairly moderate nature and a relative wide-safety range of dosage,their doses may not be used so strictly as those of chemicals, but must within the limitation. The Traditional Chinese Medical dosage is yet affected by the follwing factors:properties of medicinal herbs,compatibility and formulation,the condition of illness,the patients’ physique and age,methods of decocting chinese medicinal herbs,methods of taking chinese medicinal,and etc. After exclude these factors, analyze the relationship between TCM prescription’ dosage and pharmacodynamic effect be of great signifiance.In this work, explore how to analyze the relationship between TCM prescription’ dosage and pharmacodynamic effect is a major goal. The paper put forward analyze the relationship between TCM prescription’ dosage and pharmacodynamic effect based on Uniform Design and regression method, It was proved to be feasible and effective after tested.
Authors: Shu Yi Yang, D.S. Liu, Z.J. Wen, Y.F. He
Abstract: In view of complexity internal structure of mobile hard disk and according to the principle of quality equivalent, a finite element model of mobile hard disk was established. Finite element simulation with dropping impact of mobile hard disk was made based on uniform design. A neural network model of nonlinear mapping relations was established between shell thickness,actuator arm thickness, cantilever thickness and pivot bearings stiffness of mobile hard disk with shell stress,disk interface stress and space with head and disk. The difference is less of the prediction values with the ANN(artificial neutral network) and the simulation datum with the FEM(finite element method). This indicates that the method is effective and may provide theory evidence for optimization crashworthiness design.
Authors: Guo Feng Wang, Wen Zhao, Yong Ping Guan, Shen Gang Li
Abstract: The selection of material parameters relates to the excavation stability of the underground caverns. However, back analysis is an efficient method to evaluate mechanical parameters. Given the defects of BP neural network, such as low capability of generalization and long training time, by using GA, which have global optimization ability to optimize the BP neural network weights. The parameter of surrounding rock was designed by uniform and orthogonal method, not only reduced the iterative time also improved the accuracy of the prediction. The proposed method is further illustrated with its application to the underground cavern of Lvchunba railway tunnel. Based on the surrounding rock’s parameters obtained by back analysis, the displacement of the surrounding rock was predicted. The results showed that the error between numerical calculation value and actual monitoring value was 13.2%,-8.3%,-8.9%,9.4% respectively.
Authors: Jie Fang Liu
Abstract: Support vector machine (SVM) is based on the principle of structural risk minimization, which makes SVM has better generalization ability than other traditional learning machines that are based on the learning principle of empirical risk minimization.Research on the application of Support vector regression (SVR) model in spectrophotometry was done to determine the content of benzoic acid and salicylic acid simultaneously. The predicted result was found highly correlated with the time when the data was collected to build the model. The closer of the dates between collecting data for modeling and for predicting, the better the predicted results. SVR model with significantly improved robustness was resulted by using all the collected data over time, which, when applied to the determination of benzoic acid and salicylic acid simultaneously, led to satisfactory result, with recoveries being 97%-102%.
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