An AHP-multicriteria suitability evaluation of technological diversification in the automotive industry

This paper advances a methodological framework for analysing the process of technological diversification in the automotive industry and presents a multicriteria procedure, based on the analytic hierarchy process (AHP), to evaluate, in a simple and user-friendly manner, the suitability of technological diversification for any company in the automotive sector. The AHP-multicriteria procedure associated with the initial stage of the methodology and the decision support systems developed to evaluate suitability have been applied to 22 Spanish automotive companies. The multicriteria procedure classifies the companies into three different groups: (i) those that are suitable for diversification; (ii) those for which product development (innovation) or market development (internationalisation) is more appropriate; (iii) those that are not suitable for any diversification process. The true value added in this initial stage of the technological diversification process is not, despite its importance, the final classification of the firms, but the learning procedure derived from the multicriteria analysis and the evaluation of diversification suitability. From this learning procedure, a set of recommendations related to the diversification of the automotive companies is extracted.     

Nonstationary response of nonlinear systems using equivalent linearization with a compact analytical form of the excitation process

A new method based on equivalent linearization approaches is presented for estimating the nonstationary response of a class of nonlinear multi-degree-of-freedom systems subjected to nonstationary excitations. The highly efficient method is based on creating a compact analytical approximation of measured nonstationary excitation process data through use of a two-stage decomposition procedure. The analytic data condensation of the excitation process is performed in two stages; (1) by performing the Karhunen–Loeve spectral decomposition on the covariance matrix of the input random process to obtain the dominant eigenvectors, and (2) by fitting these eigenvectors with orthogonal polynomials to produce a truncated series of analytically approximated eigenvectors. The efficiency and accuracy of the method is demonstrated through simulation with synthetically generated excitation data as well as measured data from a real-world physical process. Although the decomposition procedure used can characterize very general input processes, because the equivalent linearization technique requires the Gaussian assumption of the response process, the constraint on applying this approach is similar to the constraints on all other equivalent linearization techniques. However, the additional freedom gained from being able to work with data-based nonstationary random processes is a significant addition to this area of research.     

Numerical investigation of the process of ventilative drying of a pipeline

A procedure for calculating the process of drying a pipeline with a desiccant is described that enables one to predict the time required for the complete removal of moisture. The influence of various factors on the rate of the process is analyzed without allowance for the temperature drop due to the heat consumed in evaporation.Translated from Inzhenerno-fizicheskii Zhurnal, Vol. 60, No. 5, pp. 804–813, May, 1991.     

A gradient‐based adaptation procedure and its implementation in the element‐free Galerkin method

A gradient‐based adaptation procedure is proposed in this paper. The relative error in the total strain energy from two adjacent adaptation stages is used as a stop‐criterion. The refinement–coarsening process is guided by the gradient of strain energy density, based on the assumption: a larger gradient needs a richer mesh and vice versa. The procedure is then implemented in the element‐free Galerkin method for linear elasto‐static problems. Numerical examples are presented to show the performance of the proposed procedure. Copyright © 2003 John Wiley & Sons, Ltd.     

Comparison of the Luus–Jaakola optimization procedure and the genetic algorithm

The success of both genetic algorithms (GA) and the Luus–Jaakola (LJ) optimization procedure in engineering optimization and the desire for efficient optimization methods arising from practical experience make the comparison of these two methods necessary. The GA and the LJ optimization procedure are compared in terms of convergence speed and reliability in obtaining the global optimum. Instead of using the number of function evaluations, this study uses computation time for comparison of convergence speed, which is more precise. Although for some problems, such as parameter estimation for the catalytic cracking process of gas oil, both GA and LJ converge to the optimum rapidly and show high reliability; in most cases, the LJ optimization procedure was found to be faster than GA and exhibited higher reliability in obtaining the global optimum. Furthermore, the LJ optimization procedure is easier to program.     

A simple element-splitting model to simulate the tensile fracture of brittle materials and its experimental verification

Because of the low tensile strength of brittle materials, the tensile fracture simulation is of great importance to the numerical study of the failure procedure of these materials. A simple element-splitting model is proposed in this paper to simulate the tensile fracture procedure based on finite element method (FEM). As an application of this model, the fracture procedure of a doughnut-shaped specimen is simulated and the numerical results are compared with the deformation fields’ evolution from an experiment on a granite specimen with the same geometry and same loading process. Results from the experiment verified the validation of the simulation model.     

A simplified analysis for the evaluation of stochastic response of elasto-plastic oscillators

The paper deals with dynamic hysteretic oscillators without post-yielding hardening, called ideal elasto-plastic oscillators, subjected to white noise. They are characterized by the fact that they do not reach stationarity even though excited by stationary stochastic processes. A simplified solution procedure to capture this behaviour is presented in this paper. It is based on modelling the accumulated plastic deformations as a homogeneous compound Poisson process. In particular, two aspects are addressed in the paper: (1) evaluation of the probabilistic parameters of the accumulated plastic deformation process; and (2) evaluation of the second-order cumulants of the response by means of closed form expressions. Although the presented results are not rigorous and rely on an empirical basis, the aim is a very handy and sufficiently accurate procedure to obtain the evaluation of the second-order probabilistic parameters of elasto-plastic oscillators. Moreover, by testing this procedure against Monte Carlo simulations, a parametric study has been conducted in order to assess the range of validity of the homogeneous compound Poisson process model. The presented procedure can be easily extended to the case of non-normal delta correlated input processes.     

Effects of carbonate and organic matter on sorption and desorption behavior of polycyclic aromatic hydrocarbons in the sediments from Yangtze River

The role of carbonate and organic matter in the sorption and desorption process of polycyclic aromatic hydrocarbons (PAHs) was studied by using a sequential separation procedure, which sequentially removed carbonate and organic matter from the natural sediment. Five PAHs were used as multi-sorbate and their sorption and desorption characteristics in separated samples were investigated. The Linear, Freundlich and Langmuir models were applied to correlate the experimental data to reveal sorption characteristics of PAHs. The results showed that the sorption mechanism was neither complete adsorption nor partition procedure. The desorption mass of PAHs was very low for all the three sediment samples, especially for higher ring PAHs. It was discovered that carbonate mainly affected sorption and desorption process of lower ring PAHs due to its influence on the physical characteristics of sediment. Organic matter remarkably affected the behavior of higher ring PAHs in the sorption and desorption procedure by determining the dominating partition process.     

Change in the structure of colloidal capillary-porous bodies in the process of heat and mass transfer

We suggest a complex procedure for investigating shrinkage stresses in the process of drying colloidal capillary-porous bodies. Different stages of structure formation in the process of heat and mass transfer are studied. The physical mechanism of shrinkage phenomena is considered. A model of the destruction of the drying product is suggested that agrees with experiment. Tver State Technical University, Russia. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 69, No. 6, pp. 954–957, November–December, 1996.     

摩擦力在ECAP成形时作用的有限元模拟

应用有限元方法对一种全新的可应用于板料的等通道角挤压(ECAP)方法中摩擦力的作用进行了有限元模拟.计算模拟结果表明,不同于常规的等通道角挤压中摩擦力的负面影响,在板料等通道角挤压方法中一定的摩擦力和尺寸精确的模具结构却是保证此类等通道角挤压正常进行的关键.     

A procedure for measuring the coherence length of the sea texture

In this paper, we deal with the analysis of the temporal coherence properties of the signal backscattered from the sea surface, in the hypothesis that it can be modeled as a compound-Gaussian process. Precisely, we address the problem of measuring to what extent a compound-Gaussian process, namely the product of a nonnegative, slowly-varying modulating signal times a rapidly varying Gaussian component, can be approximated by a Gaussian process with random variance. The problem is restated in terms of a binary hypothesis test, wherein the null hypothesis of constant modulating sequence is contrasted to any alternative. The test is calibrated resorting to pseudorandom sequences and, finally, the procedure is applied to measuring the coherence length of sea data collected by scatterometers mounted on the “Forschungsplatform Nordsee” during the SAXON experiment in November 1990     

Mathematical model of the modes of thermal treatment of rotating glass bodies with optimal speed

A procedure of control over the modes of cooling of rotating glass bodies with optimal speed is proposed (with certain restrictions imposed on the time and residual stresses formed in the process of cooling). The application of this procedure significantly decreases the duration of cooling. Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 44, No. 6, pp. 53–57, November–December, 2008.     

Bayesian approach to the analysis of fluorescence correlation spectroscopy data I: theory

Fluorescence correlation spectroscopy (FCS) is a powerful tool to infer the physical process of macromolecules including local concentration, binding, and transport from fluorescence intensity measurements. Interpretation of FCS data relies critically on objective multiple hypothesis testing of competing models for complex physical processes that are typically unknown a priori. Here, we propose an objective Bayesian inference procedure for testing multiple competing models to describe FCS data based on temporal autocorrelation functions. We illustrate its performance on simulated temporal autocorrelation functions for which the physical process, noise, and sampling properties can be controlled completely. The procedure enables the systematic and objective evaluation of an arbitrary number of competing, non-nested physical models for FCS data, appropriately penalizing model complexity according to the Principle of Parsimony to prefer simpler models as the signal-to-noise ratio decreases. In addition to eliminating overfitting of FCS data, the procedure dictates when the interpretation of model parameters are not justified by the signal-to-noise ratio of the underlying sampled data. The proposed approach is completely general in its applicability to transport, binding, or other physical processes, as well as spatially resolved FCS from image correlation spectroscopy, providing an important theoretical foundation for the automated application of FCS to the analysis of biological and other complex samples.     

Adaptive step size selection for use with the continuation method

An adaptive procedure for selecting the step size when incremental or continuation methods are used to solve sets of non-linear equations is presented. The increment size is limited by requiring the corrective iteration procedure employed to reduce the drifting error to be within a contractive boundary at each level. The usefulness of the procedure is extended by the development of a set of conditions for detecting impending divergence of the corrective iteration process. These conditions, used in conjunction with the step size selection procedure permit the continuation of the solution through highly non-linear regions and also provide a simple means of isolating a limit point, if one exists. Two additional benefits of the procedure are an effective convergence criterion for terminating the iteration process and a simple means for switching between the Newton-Rephson and modified Newton-Raphson iteration procedures. The paper concludes with a number of example problems, three are hyperelastic bodies at finite strain and the final example is the large displacement analysis of an elastic beam. The results illustrate that the procedure is computationally inexpensive, using only information normally obtained in a non-linear analysis, flexible in the sense that a dense or sparse distribution of points along the total solution curve may be obtained, and effective, normally requiring less total computational effort than a constant step size procedure.     

Rational Design of the Structure of a Tubular Element of a Cross-Reinforced Plastic

We propose a procedure of manufacturing tubular elements from a cross-reinforced plastic and their adhesive junctions with end reinforcement. Elements are created by winding a continuous fiber with the simultaneous attachment of metallic nozzles on the ends of a pipe in the process of its formation. The potentialities and advantages of the procedure are demonstrated. By a test of tubular elements for short-term strength, we established the form of a junction and the rational scheme of reinforcement of the material that provide the maximum strength on tension.     

Pattern matching for variation-source identification in manufacturing processes in the presence of unstructured noise

Variation-source identification has received considerable attention from the manufacturing quality improvement community. One widely used method is based on a pattern matching procedure, which identifies process faults by comparing the fault symptom, which is the principal eigenvector of the covariance matrix of the quality measurement, with fault signatures. The presence of unstructured noise as well as the uncertainty due to sampling will cause the direction of the fault symptom to deviate from the corresponding fault signature. The influences of these two effects on pattern matching procedures have previously been studied separately, by assuming either the absence of unstructured noise or the availability of large samples. This paper developes a robust pattern matching procedure that considers both effects simultaneously. Using a machining process as an illustrative example, the paper demonstrates that previous pattern matching procedures can have a remarkably low identification capability when the assumptions are not strictly satisfied. By contrast, our proposed method is more robust, maintaining a good identification probability, and would be a preferable tool for root-cause identification in manufacturing quality improvement.     

Support value of sketching in the design process

This study presents an experimental investigation dealing with the support value of sketching activity in the early stages of the design process. The main focus is the process of sketching, including the sketching activity and the simultaneous use of the produced sketches. Sketching has a positive impact on the quality of the designed solution and on the individual experience of the design process. The quality of the solution concepts increases from entirely mental design problem solving without external support over partly supported to completely supported problem solving. On the basis of a representative case, the procedure of sketching and the activities performed while generating a design solution are analysed. A continuous change between internal mental and external materializing activities can be seen in the design process. Electronic Publication     

March-Dollase函数在计算铜带择优取向上的应用

根据XRD衍射图谱分析了Cu加工的择优取向行为,采用极密度相除的方法对March-Dollase函数求解过程进行了简化,使之可以直接根据XRD衍射图谱的若干峰值算出r值,间接计算择优取向的体积分数.把实测样品的XRD衍射花样与由Rietveld程序根据March-Dollase函数反推的XRD衍射花样进行对比,发现当r值小于0.45时两者符合良好,说明在此条件下(r<0.45)本数值计算方法对r值的计算准确可靠,能够估算择优取向体积分数.     

钢箱梁制作过程质量控制浅谈

箱型结构梁（以下简称箱型梁）作为钢梁的一种结构型式,以其结构新颖、承载能力强、刚性大、稳定性好等优点,在铁路桥梁、公路桥梁、水利电力、工民建等行业的钢结构工程中应用非常广泛。本文主要从下料、拼配、焊接、矫正等工序的过程控制要点,阐述箱梁制作的主要工序和各工序的质量控制。     

Heat transfer and cure analysis for the pultrusion of a fiberglass-vinyl ester I beam

In the present paper, the heat transfer and curing process during the pultrusion of a fiberglass-vinyl ester I beam is simulated using a finite element/control volume procedure developed at the Cooperative Research Centre for Advanced Composite Structures (CRC-ACS). The governing equations for the pultrusion process are introduced. The numerical algorithm adapted to solve the equations is briefly described. Numerical simulations are conducted to obtain the temperature and curing profiles for different temperature settings and pull speeds. The predicted temperature profiles are compared with those obtained experimentally. Good agreement is observed. The result of the present work enhances our confidence in applying the numerical procedure as a routine design and analysis tool for the pultrusion tooling and process development.