Based on the elastic-plastic large deformation finite element formulation as well as the shell element combined discrete Kirchhoff theoretical plate element (DKT) with membrane square element, deep-drawing bending spr...Based on the elastic-plastic large deformation finite element formulation as well as the shell element combined discrete Kirchhoff theoretical plate element (DKT) with membrane square element, deep-drawing bending springback of typical U-pattern is studied. At the same time the springback values of the drawing of patterns' unloading and trimming about the satellite aerial reflecting surface are predicted and also compared with those of the practical punch. Above two springbacks all obtain satisfactory results, which provide a kind of effective quantitative pre-prediction of springback for the practical engineers.展开更多
This paper proposes to use substrate materials of small electromechanical coupling coefficient k2 (such as X-112YLiTaO3) to manufacture wavelet transform element of SAW type so as to reduce finger reflections, i.e. to...This paper proposes to use substrate materials of small electromechanical coupling coefficient k2 (such as X-112YLiTaO3) to manufacture wavelet transform element of SAW type so as to reduce finger reflections, i.e. to reduce the error of wavelet transform element of SAW type. And it is concluded that the smaller the center frequency of the transmitting IDT of wavelet type, the smaller the error. We suggest to choose substrate material with electromechanica coupling coefficient smaller than that of X-112Y LiTaO3 in the manufacture of the transmitting IDTs of wavelet type and the receiving IDTs at center frequencies above 100MHZ, so as to reduce the errors of the transmitting IDTs of wavelet type and the receiving IDTs at center frequencies above 100MHZ.展开更多
基金This project is supported by National Natural Science Foundation of China (No.19832020)Provincial Natural Science Foundation of Jilin (No.20000519)
文摘Based on the elastic-plastic large deformation finite element formulation as well as the shell element combined discrete Kirchhoff theoretical plate element (DKT) with membrane square element, deep-drawing bending springback of typical U-pattern is studied. At the same time the springback values of the drawing of patterns' unloading and trimming about the satellite aerial reflecting surface are predicted and also compared with those of the practical punch. Above two springbacks all obtain satisfactory results, which provide a kind of effective quantitative pre-prediction of springback for the practical engineers.
基金supported by the National Natural Science Foundation of China(Grants No.60176020 and 60476037)863 Project of China(No.2001AA313090)the Doctor Foundation of Education Ministry of China(No.20020698014).
文摘This paper proposes to use substrate materials of small electromechanical coupling coefficient k2 (such as X-112YLiTaO3) to manufacture wavelet transform element of SAW type so as to reduce finger reflections, i.e. to reduce the error of wavelet transform element of SAW type. And it is concluded that the smaller the center frequency of the transmitting IDT of wavelet type, the smaller the error. We suggest to choose substrate material with electromechanica coupling coefficient smaller than that of X-112Y LiTaO3 in the manufacture of the transmitting IDTs of wavelet type and the receiving IDTs at center frequencies above 100MHZ, so as to reduce the errors of the transmitting IDTs of wavelet type and the receiving IDTs at center frequencies above 100MHZ.
