Papers by Keyword: Response Surface Method (RSM)

Abstract: There have been few reports dealing with the drilling of printed wiring boards (PWBs) with micro-drills that are smaller than 0.2 mm in diameter, and super-high-speed spindles that are higher than 160,000 rpm. In these cases, preventing the micro-drill from breaking and keeping the position accuracy of the drilled hole has been difficult. We therefore focus on the high-speed step-drilling method and short stroke as a novel way of resolving these problems. On the other hand, determining the complicated combination of feed speed, rapid feed speed, and stroke length is difficult. Under these backgrounds, in this report we propose a fast-feed step cycle that use fast-feed command without the processing feed. Thus, we attempted to apply the response surface method to optimize these parameters. As a result, a proposed method was found to be effective to improve the drilled hole quality and drilling efficiency in such kinds of micro-drilling of the PWBs.

Abstract: Machining is often performed by a machining center using various cutting tools and conditions for different shapes and materials. Recent improvements in CAM system make it easier for even unskilled engineers to generate NC programs. In the NC program, the end-milling conditions are decided by engineers. However, engineers need to decide the order of the process, cutting tool selection, and the end-milling conditions on the basis of their expertise and background knowledge because the CAM system cannot automatically decide. Data-mining methods were used to support decisions about end-milling conditions. Our aim was to extract new knowledge by applying data-mining techniques to a tool catalog. We used both hierarchical and non-hierarchical clustering of catalog data and also used applied multiple regression analysis. We focused on the shape element of catalog data and we visually grouped ball end-mills from the viewpoint of tool shape, which here meant the ratio of dimensions, by using the k-means method. We also found an expression for calculating end-milling conditions, and we compared the calculated with the catalog values.

Abstract: The ANN-based optimization for considering fatigue reliability requirements in structural optimization was proposed. The ANN-based response surface method was employed for performing fatigue reliability analysis. The fatigue reliability requirements were considered as constraints while the weight as the objective function, the ANN model was adopted to establish the relationship between the fatigue reliability and geometry dimension of the structure, the optimal results of the structure with a minimum weight was reached.

Abstract: Sugarcane bagasses were used as raw materials to produce the hemicelluloses, and the effects of temperature, alkali consumption, time and liquid to solid ratio on the extraction yield of hemicelluloses were investigated. Through the analysis of the response surface method, results were concluded that the best extraction process conditions were as follows: NaOH concentration 10.60%, extraction time 4.34 h, solid-liquid ratio 1:40.59, actual extraction rate is 31.486%, corresponding to the model prediction 31.4447% basically.

Abstract: We proposed the data-mining methods using hierarchical and non-hierarchical clustering methods to help engineers decide appropriate end-milling conditions. The aim of our research is to construct a system that uses clustering techniques and tool catalog data to support the decision of end-milling conditions for difficult-to-cut materials. We used variable cluster analysis and the K-means method to find tool shape parameters that had a linear relationship with the end-milling conditions listed in the catalog. We used the response surface method and significant tool shape parameters obtained by clustering to derive end-milling condition. Milling experiments using a square end mill under two sets of end-milling conditions (conditions derived from the end-milling condition decision support system and conditions suggested by expert engineers) for difficult-to-cut materials (austenite stainless steel) showed that catalog mining can be used to derive guidelines for deciding end-milling conditions.

Abstract: In order to improve dynamic characteristics of a machining center column, this paper proposes a structural optimization method based on finite element method (FEM) and response surface method (RSM). In order to reduce number of design variables, the finite element analysis samples in design space are selected by using the central composite design (CCD) experiment method. On the basis of FEM results at these experiment samples, quadratic polynomials are employed to establish response surface model, which reflects the relationship between the response (mean frequency of the first four orders) and the design variables (the column structural sizes). The goal of getting maximum mean frequency is reached by using NLPQL algorithm in iSIGHT. Through the optimization, the mean frequency is increased by 8.12%.

Abstract: Ultra-high pressure extraction technique was used to extract polysaccharides from Dendrobium candidum. Extraction pressure, pressure holding time and liquid-solid ratio were found to have a significant influence on the polysaccharides extraction and were optimized by the response surface method (RSM). The obtained optimum conditions were: extraction pressure 445.28MPa, pressure holding time 6.7 minutes and liquid-solid ratio 237.91ml/g. The maximum polysaccharide yield could reach 596.75mg/g under these conditions. The ultra-high pressure extraction process was a suitable method for its higher yield and shorter extraction time compared to the water-heating extraction.

Abstract: The response surface method was proposed as a collection of statistical and mathematical techniques that are useful for modeling and analyzing a system which is influenced by several input variables. This method gives an explicit approximation of the implicit limit state function of the structure through a number of deterministic structural analyses. However, the position of the experimental points is very important to improve the accuracy of the evaluation of failure probability. In the paper, the experimental points are obtained by using Givens transformation in such way these experimental points nearly close to limit state function. A Numerical example is presented to demonstrate the improved accuracy and computational efficiency of the proposed method compared to the classical response surface method. As seen from the result of the example, the proposed method leads to a better approximation of the limit state function over a large region of the design space, and the number of experimental points using the proposed method is less than that of classical response surface method.

Abstract: The response surface method (RSM) is widely used to alleviate the computational burden of engineering analyses. For reliability analysis, the common approach in the RSM is to use a linear interpolation technique. However, the experimental points are all arranged using the classical RSM in each process of interpolation. Therefore, the number of experimental points is large that resulting in the efficiency is lower. In this study, an improvement of the RSM for structural reliability analysis has been proposed based on the technique of successive linear interpolation. As seen from the example, the proposed method yields better results than those of the classical RSM, and the number of experimental points using the proposed method is less than that of classical RSM. It seems that the proposed method improves the convergence speed and reduces the computational effort.

Abstract: A design method of reliability-based structural optimization has a powerful advantage because some random variables can be considered. However, the sensitivity analysis of reliability with respect to random variables is very complicated and its computational cost is very expensive. Thus, a response surface method is adopted for approximating the limit state function to improve computational efficiency. An iterative strategy is used to determine a response surface that is able to fit the limit state function in the neighborhood of the design point. A sequential response surface method is performed to satisfy the demand of accuracy in the process of reliability-based structural optimization. A numerical example is presented to demonstrate the computational efficiency of the proposed method.