爆破振动对古建筑物安全影响的研究

爆破振动一般采用萨道夫斯基公式进行回归分析,求得K,α值,需要大量的振动速度监测数据来控制误差。对比了传统的最小二乘法的线性回归分析方法和构造方程-求导-迭代的非线性回归分析方法,发现在数据量较少的情况下,非线性回归分析方法取得了较为真实且误差更小的结果,并以缅甸莱比塘铜矿采区内古建筑物周边爆破振动控制实例为背景,利用非线性回归分析方法处理已测振动监测数据,得到适用于此古建筑物周边地质条件的K=151、α=1.702以及误差r=29.2%,以此指导爆破设计、施工及振动预测,有效的保护了古建筑物的安全。     

爆破振动对古建筑物安全影响的研究

爆破振动一般采用萨道夫斯基公式进行回归分析,求得K,α值,需要大量的振动速度监测数据来控制误差。对比了传统的最小二乘法的线性回归分析方法和构造方程-求导-迭代的非线性回归分析方法,发现在数据量较少的情况下,非线性回归分析方法取得了较为真实且误差更小的结果,并以缅甸莱比塘铜矿采区内古建筑物周边爆破振动控制实例为背景,利用非线性回归分析方法处理已测振动监测数据,得到适用于此古建筑物周边地质条件的K=151、α=1.702以及误差r=29.2%,以此指导爆破设计、施工及振动预测,有效的保护了古建筑物的安全。     

Fatigue design of a cellular phone folder using regression model-based multi-objective optimization

In a folding cellular phone, the folding device is repeatedly opened and closed by the user, which eventually results in fatigue damage, particularly to the front of the folder. Hence, it is important to improve the safety and endurance of the folder while also reducing its weight. This article presents an optimal design for the folder front that maximizes its fatigue endurance while minimizing its thickness. Design data for analysis and optimization were obtained experimentally using a test jig. Multi-objective optimization was carried out using a nonlinear regression model. Three regression methods were employed: back-propagation neural networks, logistic regression and support vector machines. The AdaBoost ensemble technique was also used to improve the approximation. Two-objective Pareto-optimal solutions were identified using the non-dominated sorting genetic algorithm (NSGA-II). Finally, a numerically optimized solution was validated against experimental product data, in terms of both fatigue endurance and thickness index.     

临近燃气管道的爆破质点峰值振速预测

为研究南宁市某水利枢纽疏浚爆破对临近燃气管道产生爆破振动的衰减规律及其影响,采用爆破振动测试仪对爆破荷载下燃气管道的振动峰值速度进行监测。根据实测数据,利用线性回归与非线性回归方法进行分析。结果表明:运用回归分析得到的预测模型拟合精度较高,且非线性回归分析的预测模型比线性回归分析的预测模型精度高。非线性回归分析模型的相对误差为5.44%,线性回归分析模型的相对误差为6.38%。     

临近燃气管道的爆破质点峰值振速预测

为研究南宁市某水利枢纽疏浚爆破对临近燃气管道产生爆破振动的衰减规律及其影响,采用爆破振动测试仪对爆破荷载下燃气管道的振动峰值速度进行监测。根据实测数据,利用线性回归与非线性回归方法进行分析。结果表明:运用回归分析得到的预测模型拟合精度较高,且非线性回归分析的预测模型比线性回归分析的预测模型精度高。非线性回归分析模型的相对误差为5.44%,线性回归分析模型的相对误差为6.38%。     

基于多目标遗传算法的山药真空干燥工艺优化

为了得到山药切片真空干燥的最优工艺参数,以平均干燥速率Y₁、单位能耗Y₂、复水比Y₃和白度指数Y₄为试验指标,以干燥温度T、压强V和切片厚度L为影响因素进行进行Box-Behnken响应面优化试验,通过多元非线性回归分析建立各指标的数学模型,最后分别使用加权评分法和遗传算法进行多目标优化。结果表明:多目标遗传算法优化结果更合理,得到的山药切片真空干燥最优工艺参数为:干燥温度63.76℃、压强0.0532 MPa和切片厚度2.46 mm,所对应的指标值为:平均干燥速率0.00897 g/(g·min)、单位能耗14.205 kW·h/kg、复水比2.078和白度指数81.220。     

Multiple predictor smoothing methods for sensitivity analysis: Example results

The use of multiple predictor smoothing methods in sampling-based sensitivity analyses of complex models is investigated. Specifically, sensitivity analysis procedures based on smoothing methods employing the stepwise application of the following nonparametric regression techniques are described in the first part of this presentation: (i) locally weighted regression (LOESS), (ii) additive models, (iii) projection pursuit regression, and (iv) recursive partitioning regression. In this, the second and concluding part of the presentation, the indicated procedures are illustrated with both simple test problems and results from a performance assessment for a radioactive waste disposal facility (i.e., the Waste Isolation Pilot Plant). As shown by the example illustrations, the use of smoothing procedures based on nonparametric regression techniques can yield more informative sensitivity analysis results than can be obtained with more traditional sensitivity analysis procedures based on linear regression, rank regression or quadratic regression when nonlinear relationships between model inputs and model predictions are present.     

Phase II Monitoring of Nonlinear Profile Variance Using Wavelet

In some statistical process control applications, the quality of a process or a product can be characterized by a nonlinear relationship between a response variable and one or more explanatory variables. Monitoring nonlinear profiles using nonlinear regression has been proposed by several researchers as a potential area for research. To avoid disadvantages of parameter estimation in nonlinear regression, we used nonparametric regression with wavelets for monitoring nonlinear profiles. In nonparametric regression framework, traditional variance estimator is not proper; other estimators should be used instead. Parametric or nonparametric control charts in phase II are proposed to monitor error term variance when nonparametric regression with wavelet is used. Multivariate control chart based on regression coefficients (approximate wavelet coefficients) is added to variance control chart to check stability in the process mean. It is well known that the performance of control schemes in detecting shifts in multivariate control charts deteriorates as the dimension of regression coefficient increases. To improve the performance of control schemes, we considered decomposition level as a smoothing parameter, which determines the form of regression function (size of approximate wavelet coefficients vector) in nonparametric regression with wavelet. A method based on an analysis of variance is proposed to determine the optimal decomposition level. The statistical performances of the proposed methods are evaluated using average run length criterion using vertical density profile data. Numerical results indicate that the proposed methods perform satisfactorily. Copyright © 2012 John Wiley & Sons, Ltd.     

Quantitative analysis of film coating in a fluidized bed process by in-line NIR spectrometry and multivariate batch calibration

A method is described which enables real-time analysis of film coating on pharmaceutical pellets during an industrial manufacturing process. Measurements were conducted on the solid particulate material by near-infrared (NIR) spectrometry utilizing a diffuse reflectance fiber-optic probe positioned inside a fluidized bed process vessel. Time series of NIR spectra from 11 batches generated a three-way data matrix that was unfolded and modeled by partial least squares (PLS) in a multivariate batch calibration. The process conditions were deliberately varied according to an experimental design. This yielded good predictability of the coating thickness with a best model fit, R2 = 0.97, for one PLS-projection, and a root-mean-square error of calibration = 2.2 microm (range tested 0-50 microm). The regression vector was shown to be highly influenced by responses that are both direct (aliphatic C-H stretch overtones) and indirect (aromatic C-H stretch overtones), from film component and core material, respectively. The impact of different data pre-treatment methods on the normalization of the regression vector is reported. Justification of the process calibration approach is emphasized by good correlation between values predicted from NIR data and reference image analysis data on dissected pellets and a theoretical nonlinear coating thickness growth model. General aspects of in-line NIR on solids and multivariate batch calibration are discussed.     

On the validity of nonlinear shear deformation theories for laminated plates and shells

This paper addresses the validity of the recently introduced so-called nonlinear shear deformation theories for laminated composite plates and shells. The finite element method is used to determine the maximum stresses for a wide range of statically loaded plate and shell panels. Various thickness ratios are included. This paper concludes that for the vast majority of composite materials and for moderately thick plates and shells. stresses normally reach the maximum allowable stress before nonlinear terms can become important. This has been demonstrated by showing that for the limiting case of shear deformation theories (in which the minimum span length (or radius) to thickness ratio is 20), the material usually fails before the maximum deflection reaches the magnitude of the thickness (where nonlinear terms start to become significant). Therefore, the nonlinear shear deformation theories, which are considerably more complicated than linear ones, have limited applications.     

加权非线性随机系数模型异方差性的Score检验

在回归分析中，随机误差的方差齐性的假设往往有助于问题的解决，但方差齐性假设并不总是正确的。在线性和非线性回归中关于异方差的诊断问题已有许多讨论，在韦博成（1995）讨论的加权非线性回归模型的基础上，用随机系数的方法，讨论加权线性随机系统模型中的异方差检验问题，得到了方差齐性检验的Score统计量。     

Analysis of high-temperature creep experiments by generalized nonlinear inversion

The present paper aims at showing that rheological equations can be obtained from creep experiments with better accurracy and reliability if the ‘generalized nonlinear inversion’ method is used rather than the more traditional linear or multi-linear regression methods. The experimental data with the relevant experimental errors can be fitted to nonlinear creep laws whose parameters are then determined. The standard deviation of the creep parameters can also be estimated. An analysis of high temperature creep data of sodium chloride single crystals is given as an example.     

Geometrically nonlinear composite beam structures: optimal design

This paper applies the formulation and the finite element analysis and sensitivity analysis model developed in a companion paper to the optimal design of various geometrically nonlinear composite laminate beam structures. The element design sensitivities are imbedded in the finite element code and the global sensitivities are interfacing the analysis with a nonlinear programming optimizer. Laminate thickness and lamina orientations are considered as design variables. Mass, stiffness and deflection are used as objectives or combined as multiobjective functions. The nonlinear critical load or the Tsai-Hill stress failure index, are used as constraints. Postcritical domain behavior allows the advantageous substitution of the critical load constraint by a displacement constraint.     

Nonlinear dynamics of FGM circular cylindrical shell with clamped-clamped edges

An analysis on the nonlinear dynamics of a clamped-clamped FGM circular cylindrical shell subjected to an external excitation and uniform temperature change is presented in this paper. Material properties of the constituents are assumed to be temperature-independent and the effective properties of FGM cylindrical shell are graded in thickness direction according to a simple power law function in terms of the volume fractions. Based on the first-order shear deformation shell theory and von Karman type nonlinear strain-displacement relationship, the nonlinear governing equations of motion are derived by using Hamilton’s principle. Galerkin’s method is then utilized to discretize the governing partial equations to a two-degree-of-freedom nonlinear system including the quadratic and cubic nonlinear terms under combined external excitations. Numerical results including the bifurcations, waveform, phase plots and Poincare maps are presented for clamped-clamped FGM cylindrical shells showing the influences of material gradient index, the thickness and the external loading on the nonlinear dynamics.     

Method for improving terahertz band absorption spectrum measurement accuracy using noncontact sample thickness measurement

The terahertz absorption spectrum has a complex nonlinear relationship with sample thickness, which is normally measured mechanically with limited accuracy. As a result, the terahertz absorption spectrum is usually determined incorrectly. In this paper, an iterative algorithm is proposed to accurately determine sample thickness. This algorithm is independent of the initial value used and results in convergent calculations. Precision in sample thickness can be improved up to 0.1 μm. A more precise absorption spectrum can then be extracted. By comparing the proposed method with the traditional method based on mechanical thickness measurements, quantitative analysis experiments on a three-component amino acid mixture shows that the global error decreased from 0.0338 to 0.0301.     

Finite Element Multi-mode Approach to Thermal Postbuckling of Functionally Graded Plates

Postbuckling analysis of functionally graded ceramic-metal plates under temperature field is presented using finite element multi-mode method. The three-node triangular element based on the Mindlin plate theory is employed to account for the transverse shear strains, and the von-Karman nonlinear strain-displacement relation is utilized considering the geometric nonlinearity. The effective material properties are assumed to vary through the thickness direction according to the power law distribution of the volume fraction of constituents. The temperature distribution along the thickness is determined by one dimensional Fourier equations of heat conduction. The buckling mode shape solved from eigen-buckling analysis is adopted as the assumed mode function to reduce the degrees of freedom of nonlinear postbuckling equilibrium equations. The postbuckling response is obtained by solving the nonlinear equilibrium equations, and compared with the Newton- Raphson numerical results. The effects of boundary conditions, material gradient index and temperature distribution on postbuckling behavior are examined.     

变厚度扁球壳的非线性分析

本文利用边界元方法分析了变厚度扁球壳的非线性问题。引入了与变厚因素有关的等效载荷(?),利用板的初等函数基本解,而不是直接寻求变厚扁球壳的基本解,使原问题的难度大大减少,采用了连续性强、精度高的样条函数插值,即使在划分节点取得较少的情况下,结果的精度是令人满意的。     

Geometrically nonlinear static and transiently dynamic behavior of laminated composite plates based on a higher order displacement field

In this work a finite element analysis of geometrically nonlinear static and transiently dynamic behavior of laminated composite plates is presented. A higher order displacement field allowing both transverse shear and transverse normal strains is adopted through the analysis. The mass matrix, linear stiffness matrix, and nonlinear stiffness matrix for a typical discretized element are derived and presented. Several numerical examples are included, where comparisons among linear and nonlinear theories, the current displacement field and other displacement fields are made. Effects of laminate thickness, stacking sequences and stacking angles are also studied. One interesting result is that even for symmetric cross ply, linear theory can not provide accurate enough results.     

光学镀膜仪的监控稳定性研究

光学镀膜仪的膜厚监控稳定性影响着镀膜的合格率，并且对镀膜经验控制，膜系修正和自动化系统开发有重要的意义。对真空镀膜仪进行4种薄膜系列的膜厚监控实验，建立一套稳定性评价体系，获取镀膜仪的稳定性指标。将修正的方差分析方法、不确定度分析方法、标准偏差与相对偏差方法和线性回归方法等综合起来，用6项指标从各个方面对光学薄膜厚度监控的稳定性做出评判，甚至对膜厚控制精度和特征波长做出分析。实验结果表明：上述的综合评价体系是合理的；多层膜比单层膜的监控稳定性稍差一些，膜层材料对稳定性的影响比较大，膜厚控制精度的标准偏差≤0．45％；薄膜层数对膜厚控制精度没有明显的影响，甚至多层膜比少层膜的控制精度要高，出现了“中心层”效应；用线性回归方法可以估计实际镀膜的特征波长长移量。     

Tailoring the structural,electrical, and optical features of Erbium(III)-Tris(8-hydroxyquinolinato) nanostructured films for optical applications: effect of film thickness

This paper elaborates on the thickness-dependent structural, optical, and electrical properties of Erbium(III)-Tris-8-hydroxyquinolinato (ErQ3) films. The surface morphology reveals the grains that consolidate to make denser films with increasing film thickness. The ErQ3 grain sizes increased from 80 to 187 nm as the thickness increased from 80 to 190 nm. From XRD analysis, the ErQ3 films are partially crystallized with only one peak at 2θ?=?9.80° and a plateau in the range of 20–40°. Electrical measurement of ErQ3 films showed that the electrical conductivity had a strong dependence on film thickness. Transmittance and reflectance measurements showed that the films exhibited a 2.60 eV bandgap, and it does not depend on the thickness of the film. Also, the dispersion of the refractive index was analyzed to determine the essential parameters. The nonlinear optical parameters such as nonlinear refractive index and third-order nonlinear optical susceptibility were calculated by Miller's principles.