Surface morphology and roughness are important parameters of surface quality of cold-rolled ultra-thin strip steel.In order to study the effect of Si_(3)N_(4) ceramic work rolls on the surface roughness of SUS304 ultr...Surface morphology and roughness are important parameters of surface quality of cold-rolled ultra-thin strip steel.In order to study the effect of Si_(3)N_(4) ceramic work rolls on the surface roughness of SUS304 ultra-thin strip,ABAQUS finite element model calculation,3D laser profilometry,and other methods were adopted based on the physical characteristics of Si_(3)N_(4) ceramic roll and 9Cr2MoV steel roll,like anti-flattening performance and oil wettability.The surface morphology and roughness of SUS304 ultra-thin strip rolled by different material work rolls under oil lubrication conditions were measured.The results showed that under the rolling force of 10 kN,the maximum flattening amount of Si_(3)N_(4) ceramic roll was reduced by 35.14%compared to that of 9Cr2MoV steel roll.The reduction rate of SUS304 ultra-thin strip rolled by ceramic roll was 34.19%,while that rolled by steel roll was only 22%;Si_(3)N_(4) ceramic roll can further increase the number of alternating convex peaks and concave valleys in the rolled thin strip,reduce the profile steepness,reduce surface roughness,and enhance the planarization effect of surface micro-convex bodies,with improving surface quality and surface glossiness.Finally,the mechanism of Si_(3)N_(4) ceramic roll significantly improving the surface roughness of rolled SUS304 ultra-thin strip was proposed.展开更多
Energy optimization is one of the key problems for ship roll reduction systems in the last decade. According to the nonlinear characteristics of ship motion, the four degrees of freedom nonlinear model of Fin/Rudder r...Energy optimization is one of the key problems for ship roll reduction systems in the last decade. According to the nonlinear characteristics of ship motion, the four degrees of freedom nonlinear model of Fin/Rudder roll stabilization can be established. This paper analyzes energy consumption caused by overcoming the resistance and the yaw, which is added to the fin/rudder roll stabilization system as new performance index. In order to achieve the purpose of the roll reduction, ship course keeping and energy optimization, the self-tuning PID controller based on the multi-objective genetic algorithm （MOGA） method is used to optimize performance index. In addition, random weight coefficient is adopted to build a multi-objective genetic algorithm optimization model. The objective function is improved so that the objective function can be normalized to a constant level. Simulation results showed that the control method based on MOGA, compared with the traditional control method, not only improves the efficiency of roll stabilization and yaw control precision, but also optimizes the energy of the system. The proposed methodology can get a better performance at different sea states.展开更多
基金supported by the National Natural Science Foundation of China (No.51974196)the Major Program of National Natural Science Foundation of China (No.U22A20188)Central Government Guides the Special Fund Projects of Local Scientific and Technological Development (YDZX20191400002149).
文摘Surface morphology and roughness are important parameters of surface quality of cold-rolled ultra-thin strip steel.In order to study the effect of Si_(3)N_(4) ceramic work rolls on the surface roughness of SUS304 ultra-thin strip,ABAQUS finite element model calculation,3D laser profilometry,and other methods were adopted based on the physical characteristics of Si_(3)N_(4) ceramic roll and 9Cr2MoV steel roll,like anti-flattening performance and oil wettability.The surface morphology and roughness of SUS304 ultra-thin strip rolled by different material work rolls under oil lubrication conditions were measured.The results showed that under the rolling force of 10 kN,the maximum flattening amount of Si_(3)N_(4) ceramic roll was reduced by 35.14%compared to that of 9Cr2MoV steel roll.The reduction rate of SUS304 ultra-thin strip rolled by ceramic roll was 34.19%,while that rolled by steel roll was only 22%;Si_(3)N_(4) ceramic roll can further increase the number of alternating convex peaks and concave valleys in the rolled thin strip,reduce the profile steepness,reduce surface roughness,and enhance the planarization effect of surface micro-convex bodies,with improving surface quality and surface glossiness.Finally,the mechanism of Si_(3)N_(4) ceramic roll significantly improving the surface roughness of rolled SUS304 ultra-thin strip was proposed.
基金Foundation item： Supported by the National Natural Science Foundation of China （Grant No. 61174047） and the Fundamental Research Funds for the Central Universities （HEUCF041406）.
文摘Energy optimization is one of the key problems for ship roll reduction systems in the last decade. According to the nonlinear characteristics of ship motion, the four degrees of freedom nonlinear model of Fin/Rudder roll stabilization can be established. This paper analyzes energy consumption caused by overcoming the resistance and the yaw, which is added to the fin/rudder roll stabilization system as new performance index. In order to achieve the purpose of the roll reduction, ship course keeping and energy optimization, the self-tuning PID controller based on the multi-objective genetic algorithm （MOGA） method is used to optimize performance index. In addition, random weight coefficient is adopted to build a multi-objective genetic algorithm optimization model. The objective function is improved so that the objective function can be normalized to a constant level. Simulation results showed that the control method based on MOGA, compared with the traditional control method, not only improves the efficiency of roll stabilization and yaw control precision, but also optimizes the energy of the system. The proposed methodology can get a better performance at different sea states.
