Orthogonal Design Theory Research Articles

Optimization Design Method for Non-Rectangular Constant Stress Accelerated Testing Considering Parameter Estimation Precision

In addressing the design challenges for constant-stress accelerated life testing in non-rectangular experimental domains, we aim to optimize the precision in estimating parameters for the product reliability statistical model. Following the principles of regression orthogonal design theory to determine the combinations of stress levels, we constrain the maximum stress levels of each experimental stress along the boundary curve of the non-rectangular experimental domain. The remaining stress levels and the allocation ratios of specimens for each test serve as design variables in the optimization process. We establish a mathematical model for the optimal design of constant-stress accelerated life testing in non-rectangular experimental domains. The results of the optimized design for comprehensive stress accelerated life testing in non-rectangular experimental regions of aerospace electrical connectors indicate that, with the same sample size, the optimized testing scheme not only enhances the precision of model parameter estimation but also reduces the number of required tests. At an equivalent number of tests and testing duration, the optimization scheme proposed in this study demonstrates an improvement of over 63% in the precision of model parameter estimation compared to the EM-optimized testing scheme in non-rectangular experimental regions. Using the mean, standard deviation, and coefficient of variation of the determinant values of the information matrix as criteria for evaluating the precision and robustness of experimental designs, a simulated evaluation was conducted for the optimized experimental design, a conventional experimental design, and an EM experimental design. The results indicate that the optimal experimental design outperforms both the conventional experimental design and the EM experimental design in terms of precision and robustness.

Optimal Design of Multi-Stress Accelerated Degradation Test within Irregular Test Region

Motorized spindle is the key functional part of the computer numerical control machine tool and its lifetime determines the reliability level of the machine tool to a great extent. Many efficient plans have been obtained for electronic products but how to design an efficient accelerated degradation test plan for the motorized spindle is still a problem to be solved. In this paper, considering the condition that the loaded stresses of the motorized spindle in practice may not reach their highest levels simultaneously, a novel optimization design method of the accelerated degradation test is proposed within the irregular test region. The orthogonal design theory and the uniform design theory are applied to determine the alternative test plans within the irregular test region for different numbers of stress levels. A numerical example is presented to illustrate the effectiveness of the proposed method. Finally, the sensitivity analysis is conducted to assess the robustness of the optimum plan on parameter variation.

Preparation and Performance Analysis of Composite Heat Insulation Concrete for Mine

In order to study the performance of composite heat insulation concrete for mine, mixture ratio design of 18 group samples were designed based on the orthogonal design theory, then its strength and thermal conductivity were test. The integrated balance method is used to analyze the test data, and established the model of thermal conductivity theory. Through comparing with the measured thermal conductivity, the effect factors on thermal conductivity and compressive strength were analyzed including cement, glass beads, sand, shale, gravel and glass fiber content. The optimal mix proportion of concrete insulation is determined in consideration of the economy. The correctness of the mix ratio is verified by using performance retest. 7d compressive strength is 28.12MPa, and it’s thermal conductivity is 1.21W/(m·K) for composite heat insulation concrete. Research results laid the foundation for insulation heat supporting structure apply to mine

Synthesis, Photoluminescence and Infrared Emissivity of SnO<sub>2</sub> Nanocrystalline Thin Films

SnO2 nanocrystalline thin films (NCTFs) with high quality and low infrared emissivity were synthesized through a simple hydrothermal process designed by orthogonal design theory. The microstructure, morphology, photoluminescence (PL) property and the infrared emissivity (IRE) property of as-prepared products were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), fluorescence spectrophotometer, and infrared spectroradio meter (ISM) respectively. The results show that two emission peaks are observed in PL spectra, which can be deconvoluted by Gaussian profile fitting into four emission peaks centered at about 380, 420, 460 and 520 nm respectively. The influences of crystallinity, concentration of particles and resistivity on IRE were systematically investigated, revealing that the better crystallinity, higher particle density and better conductivity are favorable for lowering IRE.

A Cutting Force Model for Face Milling Operation

Based on the geometry of the cutter, the dynamic force model of face milling was established. Meanwhile, the fast and effective identification method of milling force model coefficients was provided, which combining the virtues of both orthogonal design theory and partial least-square regression (PLSR) method. Milling experiments have been conducted to verify the proposed face milling force model. Good agreements between the experimental and simulated results were presented.

Mix Proportion Design of Acid Pink 3B Fluorescent Magnetic Powder Based on Orthogonal Theory

A new method for preparing Acid pink 3B fluorescent magnetic powder was proposed based on theorthogonal theory and currentpreparing experience experiments of fingerprints development. The method contains two steps, first the level of each facor should be determined by the single factor expermint, then the best matrix of Acid pink 3B fluorescent magnetic powder should be selected by the orthogonal design theory.

Rock Slope Fuzzy Stochastic Damage Study

Fuzzy sub-space, with analysis on generalized uncertainty of damage, is setup in this paper when topological consistency of damage fuzzy and randomness on [0,1] scale being demonstrated deeply. Furthermore, deduced under fuzzy characteristics translation are three fuzzy analytical models of damage functional, namely, half depressed distribution, swing distribution, combined swing distribution, by which, fuzzy extension territory on damage evolution is formulated here. With the representation of damage variable β probabilistic distribution as well as formulation on stochastic sub-space of damage variable, expended on the basis of extension criterion and fuzzy probability is damage model defined within generalized uncertain space, by which, introduced is fuzzy probabilistic integral algorithm of generalized uncertain damage variable that could be simulated by the forthcoming fuzzy stochastic damage constitution model based on three fuzzy functional models before. Moreover, in order to realize the joint of fuzzy input and output procedure on generalized uncertain damage variable calculation, fuzzy self-adapting stochastic damage reliability algorithm is, with the update on fuzzy stochastic finite element method within standard normal distribution probabilistic space by the help of foregoing fuzzy stochastic damage constitution model, offered in this paper on the basis of equivalent-normalization and orthogonal design theory.

Super Gravity Dam Generalized Damage Study

Fuzzy sub-space, with analysis on generalized uncertainty of damage, is setup in this paper when topological consistency of damage fuzzy and randomness on [0,1] scale being demonstrated deeply. Furthermore, deduced under fuzzy characteristics translation are three fuzzy analytical models of damage functional, namely, half depressed distribution, swing distribution, combined swing distribution, by which, fuzzy extension territory on damage evolution is formulated here. With the representation of damage variable ß probabilistic distribution as well as formulation on stochastic sub-space of damage variable, expended on the basis of extension criterion and fuzzy probability is damage model defined within generalized uncertain space, by which, introduced is fuzzy probabilistic integral algorithm of generalized uncertain damage variable that could be simulated by the forthcoming fuzzy stochastic damage constitution model based on three fuzzy functional models before. Moreover, in order to realize the joint of fuzzy input and output procedure on generalized uncertain damage variable calculation, fuzzy self-adapting stochastic damage reliability algorithm is, with the update on fuzzy stochastic finite element method within standard normal distribution probabilistic space by the help of foregoing fuzzy stochastic damage constitution model, offered in this paper on the basis of equivalent-normalization and orthogonal design theory. 3-dimension fuzzy stochastic damage mechanical status of numerical model of Longtan Rolled-Concrete Dam is researched here by fuzzy stochastic damage finite element method program under property authority. Random field parameters’ statistical dependence and non-normality are considered comprehensively in fuzzy stochastic damage model of this paper, by which, damage uncertainty’s proper development and conception expansion as well as fuzzy and randomness of mechanics are hybridized overall in fuzzy stochastic damage analysis process.

Hydrothermal synthesis and dielectric properties of chrysanthemum-like ZnO particles

By orthogonal design theory, technological parameters of chrysanthemum-like ZnO particles prepared in a hydrothermal process are optimized. This paper reports a set of technological parameters for growing chrysanthemum-like ZnO particles on a large scale. It investigates the morphologies and crystalline structures of the as-synthesized three-dimensional ZnO particles with a scanning electron microscope, x-ray diffractometer and transmission electron microscope, and the possible growth mechanism on the three-dimensional ZnO particles. The experimental results indicate that the values of ∊′, ∊″ and tan δe gradually increase in the X band with the improvement of the developmental level of chrysanthemum-like ZnO particles, implying that the electromagnetic wave absorbing property depends on the morphologies of three-dimensional ZnO particles.

Optimization of (002)-Oriented ZnO Film Synthesis in Sol-Gel Process and Film Photoluminescence Property

By orthogonal design theory, technological parameters of the (002)-oriented ZnO film prepared in sol-gel process are optimized. A set of technological parameters for growing highly (002)-oriented ZnO film is obtained. As a result, it is proven that the Zn2+ concentration is the most important factor to grow a highly (002)-oriented ZnO film. We take an appropriate Zn2+ concentration 0.35 mol/L for the aimed film, of which photoluminescence property is better than those of the films derived from other Zn2+ concentrations precursor solution. The Zn2+ concentration either larger or smaller than 0.35 mol/L leads to the (002)-oriented degree decrease of films. By employing an atom force microscope, a hexagonal atom arrangement, which indicates that the film site detected is a ZnO single crystal, is observed in the surface of the highly (002)-oriented film.

Space-Time Diversity Using Orthogonal and Amicable Orthogonal Designs

In this paper we consider the utilization of multiple transmitter and receiver antennas for space-time diversity. The optimal SNR scheme, which also provides the best diversity, is outlined. This scheme however involves a reduction in the data rate. Coding schemes are then presented which not only achieve the optimal SNR but also mitigate the reduction of data rate. The proposed schemes are based on the theory of Orthogonal Designs and Amicable Orthogonal Designs.