In this paper, the relationship between steel and chemical elements is explored. A production record of a steel mill is adopted for two years, which is used as the basic data to standardize the data. Then, according t...In this paper, the relationship between steel and chemical elements is explored. A production record of a steel mill is adopted for two years, which is used as the basic data to standardize the data. Then, according to the correlation coefficient method between the hot-rolled ribs No. 1 and No. 2 hot-rolled ribs, the correlation between the two sets of data is analyzed. The main influencing factors of the hot-rolled ribs properties are obtained qualitatively. Then, the logistic regression method is used. Finally, according to the national standard of Chinese steel, the linear optimization model of Cr and Mn and V elements was established, and the change range of Cr was obtained without affecting the performance of hot rolled ribs.展开更多
The expressions of the internal forces of the webs under the vertical loads of the simply supported beam type trusses with vertical and horizontal webs and without vertical webs are studied through the mathematical fo...The expressions of the internal forces of the webs under the vertical loads of the simply supported beam type trusses with vertical and horizontal webs and without vertical webs are studied through the mathematical formula method. The variations of internal forces under different angles and spacings of the webs are simulated. The law of the optimal arrangement of the webs of the parallel-string simple-beam truss is obtained: under the condition that the rigidity of the rod is allowed, the form of no vertical web-type truss and reducing the span distance and inclination of the side span are advisable, which can save materials and reduce the weight as well. This method can be applied to the calculation of internal forces for arbitrary loads and truss forms.展开更多
In order to obtain the main and secondary factors affecting the properties of the screw steel and its correlation, this text constructed a TOPSIS (Technique for order performance by similarity to ideal solution) evalu...In order to obtain the main and secondary factors affecting the properties of the screw steel and its correlation, this text constructed a TOPSIS (Technique for order performance by similarity to ideal solution) evaluation system based on entropy weight. First of all, three properties indexes of deformed steel bar are selected: the yield strength, tensile strength and elongation at break after breaking. Secondly, we defined a comprehensive index C which is for measuring the property of thread steel by using TOPSIS method, and then the correlation degree of various chemical elements and comprehensive index C were analyzed. According to the principle that the bigger of coefficient correlation, the greater impact, to draw a conclusion: the main elements that affect the properties of deformed steel bar are C, Ceq, Si and Cr, the secondary factors are Mn, Mo, ALT, Ni, Cu, Cr, S, P and V. Finally, the correlation between various elements was studied by means of correlation analysis, where there was a significant positive correlation between Cu and Cr.展开更多
In this paper,matrix representations of the best spline quasi-interpolating operator over triangular sub-domains in S_(2)^(1)(△_(mn)^(2),and coefficients of splines in terms of B-net are calculated firstly.Moreover,b...In this paper,matrix representations of the best spline quasi-interpolating operator over triangular sub-domains in S_(2)^(1)(△_(mn)^(2),and coefficients of splines in terms of B-net are calculated firstly.Moreover,by means of coefficients in terms of B-net,computation of bivariate numerical cubature over triangular sub-domains with respect to variables x and y is transferred into summation of coefficients of splines in terms of B-net.Thus concise bivariate cubature formulas are constructed over rectangular sub-domain.Furthermore,by means of module of continuity and max-norms,error estimates for cubature formulas are derived over both sub-domains and the domain.展开更多
文摘In this paper, the relationship between steel and chemical elements is explored. A production record of a steel mill is adopted for two years, which is used as the basic data to standardize the data. Then, according to the correlation coefficient method between the hot-rolled ribs No. 1 and No. 2 hot-rolled ribs, the correlation between the two sets of data is analyzed. The main influencing factors of the hot-rolled ribs properties are obtained qualitatively. Then, the logistic regression method is used. Finally, according to the national standard of Chinese steel, the linear optimization model of Cr and Mn and V elements was established, and the change range of Cr was obtained without affecting the performance of hot rolled ribs.
文摘The expressions of the internal forces of the webs under the vertical loads of the simply supported beam type trusses with vertical and horizontal webs and without vertical webs are studied through the mathematical formula method. The variations of internal forces under different angles and spacings of the webs are simulated. The law of the optimal arrangement of the webs of the parallel-string simple-beam truss is obtained: under the condition that the rigidity of the rod is allowed, the form of no vertical web-type truss and reducing the span distance and inclination of the side span are advisable, which can save materials and reduce the weight as well. This method can be applied to the calculation of internal forces for arbitrary loads and truss forms.
文摘In order to obtain the main and secondary factors affecting the properties of the screw steel and its correlation, this text constructed a TOPSIS (Technique for order performance by similarity to ideal solution) evaluation system based on entropy weight. First of all, three properties indexes of deformed steel bar are selected: the yield strength, tensile strength and elongation at break after breaking. Secondly, we defined a comprehensive index C which is for measuring the property of thread steel by using TOPSIS method, and then the correlation degree of various chemical elements and comprehensive index C were analyzed. According to the principle that the bigger of coefficient correlation, the greater impact, to draw a conclusion: the main elements that affect the properties of deformed steel bar are C, Ceq, Si and Cr, the secondary factors are Mn, Mo, ALT, Ni, Cu, Cr, S, P and V. Finally, the correlation between various elements was studied by means of correlation analysis, where there was a significant positive correlation between Cu and Cr.
基金This work was supported by the Fundamental Research Funds for the Central Universities of Hohai University(Grant No.2019B19414,2019B44914)the Natural Science Foundation of Jiangsu Province for the Youth(Grant No.BK20160853)+2 种基金Key Laboratory of Ministry of Education for Coastal Disaster and Protection,Hohai University(Grant No.202011)the National Natural Science Foundation of China(Grant No.11601151)the National Science Foundation of Zhejiang Province(Grant No.LY19A010003).
文摘In this paper,matrix representations of the best spline quasi-interpolating operator over triangular sub-domains in S_(2)^(1)(△_(mn)^(2),and coefficients of splines in terms of B-net are calculated firstly.Moreover,by means of coefficients in terms of B-net,computation of bivariate numerical cubature over triangular sub-domains with respect to variables x and y is transferred into summation of coefficients of splines in terms of B-net.Thus concise bivariate cubature formulas are constructed over rectangular sub-domain.Furthermore,by means of module of continuity and max-norms,error estimates for cubature formulas are derived over both sub-domains and the domain.
