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Correlation between cutting force and surface roughness based on Copula function |
School of Mechanical Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China |
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Abstract To predict the surface roughness in machining process, the nonlinear correlation between common monitoring parameters of cutting force and surface roughness should be quantitatively described. The sample values of cutting force and the surface roughness were obtained by turning 7075 high strength aluminum alloy by control variable method. The marginal distribution functions were established, and the multivariate joint distribution function was constructed by the optimized Copula function. Based on the Copula function theory and the joint function model, the global, local and tail relationship between cutting force and surface roughness was analyzed. The results show that the cutting force has obviously positive correlation with surface roughness. The correlation structure is centrosymmetric, and the correlation degrees at the both ends are larger than that at the center. The tail correlation coefficient tends to zero, which illuminates that the tail correlation degree is small.
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Received: 02 March 2017
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