The variation in temperature of the blank would make major contribution to the mechanical properties of final component in hot stamping of ultra high strength steel(UHSS).It is important to use accurate thermal contac...The variation in temperature of the blank would make major contribution to the mechanical properties of final component in hot stamping of ultra high strength steel(UHSS).It is important to use accurate thermal contact conductance(TCC) to carry out finite element simulation of hot stamping for reliable caculation results.In this paper,a flat compression test was performanced on a servo press.A fast response temperature measurement and data acquisition system was designed to obtain the temperature history of blank and die under different pressures.The thermal contact conductance between blank and die was got using an optimization algorithm.The error between the temperature curves using calculated thermal contact conductance and the curves of measurement temperature was analyzed.Result shows that reliable simulation results of temperature can be got through accurate thermal contact conductance.展开更多
In order to improve the test accuracy of CCD,a new type of CCD device is proposed.Several columns(rows) of photoelectric diodes(PDs) are combined together,and staggered with the distance of H1=H/N,where H is the space...In order to improve the test accuracy of CCD,a new type of CCD device is proposed.Several columns(rows) of photoelectric diodes(PDs) are combined together,and staggered with the distance of H1=H/N,where H is the space between two adjacent PDs,and N is the number of columns(rows).The photoelectric signals are collected simultaneously by multi-channel A/D,and the accurate measurement result is obtained through appropriate signal processing.Without changing the size or space of PDs,more photographic pixels are arranged in the given direction within a finite length.Diameters of three standard poles are measured by a single CCD and two staggered CCDs,respectively with length of 30 mm and diameters of 5 mm,8 mm and 12 mm,respectively.The results show that the accuracy of double staggered CCDs is two times of that of single CCD.The new type of CCDs can avoid the impact of PD space theoretically and higher measurement accuracy can be obtained.展开更多
基金North Dakota Agricultural Experiment Station Precision Agriculture Graduate Research Assistantship(6064-21660-001-32S)USDAAgricultural Research Service Project(435589)。
基金supported by the National Basic Research Program of China ("973" Program) (Grant No. 2010CB630802-3)
文摘The variation in temperature of the blank would make major contribution to the mechanical properties of final component in hot stamping of ultra high strength steel(UHSS).It is important to use accurate thermal contact conductance(TCC) to carry out finite element simulation of hot stamping for reliable caculation results.In this paper,a flat compression test was performanced on a servo press.A fast response temperature measurement and data acquisition system was designed to obtain the temperature history of blank and die under different pressures.The thermal contact conductance between blank and die was got using an optimization algorithm.The error between the temperature curves using calculated thermal contact conductance and the curves of measurement temperature was analyzed.Result shows that reliable simulation results of temperature can be got through accurate thermal contact conductance.
基金supported by the National Natural Science Foundation of China (No.51005188)the Fund of Key Laboratory of Manufacturing and Automation of Xihua University (No.SZJJ2009-023)the University Talent Foundation of Xihua University (No.R0720221)
文摘In order to improve the test accuracy of CCD,a new type of CCD device is proposed.Several columns(rows) of photoelectric diodes(PDs) are combined together,and staggered with the distance of H1=H/N,where H is the space between two adjacent PDs,and N is the number of columns(rows).The photoelectric signals are collected simultaneously by multi-channel A/D,and the accurate measurement result is obtained through appropriate signal processing.Without changing the size or space of PDs,more photographic pixels are arranged in the given direction within a finite length.Diameters of three standard poles are measured by a single CCD and two staggered CCDs,respectively with length of 30 mm and diameters of 5 mm,8 mm and 12 mm,respectively.The results show that the accuracy of double staggered CCDs is two times of that of single CCD.The new type of CCDs can avoid the impact of PD space theoretically and higher measurement accuracy can be obtained.