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振幅改变对TC4线性摩擦焊接头微观缺陷特征的影响 被引量:3
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作者 朱剑桥 张彦华 +1 位作者 张田仓 孙成彬 《焊接学报》 EI CAS CSCD 北大核心 2014年第3期105-108,118,共4页
从力学角度研究了振幅改变对TC4线性摩擦焊接头微观缺陷特征的影响.结果表明,接头典型微观缺陷主要有微孔和三叉形貌两种,微孔是界面未完全融合导致的结果,而三叉形貌是振动方向飞边与垂直振动方向飞边分离的结果.焊接过程中摩擦压力及... 从力学角度研究了振幅改变对TC4线性摩擦焊接头微观缺陷特征的影响.结果表明,接头典型微观缺陷主要有微孔和三叉形貌两种,微孔是界面未完全融合导致的结果,而三叉形貌是振动方向飞边与垂直振动方向飞边分离的结果.焊接过程中摩擦压力及摩擦剪切力产生的耦合力学效应决定三叉形貌的状态,焊接热输入与金属空间位移的耦合效应决定微孔的大小.当其它工艺参数一定时,存在某一临界振幅Acr,当振幅A≤Acr时,随着振幅的增大,三叉形貌枝叉长度及角度分别存在极小值与极大值,最大微孔直径则持续减小.当振幅A>Acr时,随着振幅的增大,三叉形貌枝叉长度及角度均减小,最大微孔直径则保持恒定值. 展开更多
关键词 线性摩擦焊 振幅 微观缺陷 三叉形貌 微孔
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TC4线性摩擦焊接头微观特征 被引量:1
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作者 朱剑桥 张彦华 +1 位作者 张田仓 孙成彬 《焊接学报》 EI CAS CSCD 北大核心 2013年第11期88-92,117,共5页
对TC4线性摩擦焊接过程中的接头微观结构形态特征进行了分析,研究了接头微观特征参数随时间的变化趋势.结果表明,焊接过程为接头界面融合过程,界面呈现完全焊合区、过渡区及完全未焊合区3个区域.完全焊合区内界面完全融合、晶粒细小,为... 对TC4线性摩擦焊接过程中的接头微观结构形态特征进行了分析,研究了接头微观特征参数随时间的变化趋势.结果表明,焊接过程为接头界面融合过程,界面呈现完全焊合区、过渡区及完全未焊合区3个区域.完全焊合区内界面完全融合、晶粒细小,为动态再结晶组织.过渡区内界面部分融合,有微孔出现.完全未焊合区内两侧金属未接触,夹杂着金属碎渣,晶粒无变形.振动方向飞边与垂直振动方向飞边分离是导致接头出现三叉形貌特征的原因.摩擦压力及顶锻力有使三叉形貌枝叉"闭合"的趋势,而摩擦剪切力有使三叉形貌枝叉"张开"的趋势. 展开更多
关键词 线性摩擦焊 微观特征 微孔 三叉形貌
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Design of control algorithm for accelerator magnet power supply with large time constant load
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作者 Xu Wang Peng Liu +6 位作者 FengLi Long WenTong Su Yao Gao XiaoLei Shi Tao Zeng GuanJian Wu Jian Cheng 《Radiation Detection Technology and Methods》 CSCD 2020年第3期383-391,共9页
Objective High Energy Photon Source-Test Facility(HEPS-TF)is a pre-research project for the construction of high energy synchrotron radiation source in the 12th five-year plan period.The purpose is to research the key... Objective High Energy Photon Source-Test Facility(HEPS-TF)is a pre-research project for the construction of high energy synchrotron radiation source in the 12th five-year plan period.The purpose is to research the key technology and develop the key equipment of high energy synchrotron radiation source.Superconducting 3W1 magnet is the first self-developed superconducting wiggler magnet in China,and it is also one of the key research topics of HEPS.The author has completed a new digital closed-loop control algorithm for the superconducting 3W1 magnet with large load time constant and the nonlinear characteristics of inductance increasing with current,namely three-branch structure algorithm.In the face of the rapid development of high energy accelerator technology,the application of intelligent technology has become an inevitable development trend in the field of accelerator magnet power supply technology.Although the digital control of accelerator magnet power supply has been widely used,it is the first time to apply the new closed-loop control algorithm to realize fast adjustment and precision tracking in accelerator superconducting magnet power supply in China.Method According to the nonlinear characteristics of inductance and output current of superconducting magnet,a new digital closed-loop control algorithm for the load of superconducting magnet power supply with large time constant is proposed.Conclusion This algorithm is quite different from the traditional algorithm and can attain the independent tracking and adjust-ment of the control target.Finally,by testing the ripple,error and stability of superconducting 3W1 magnet power supply,the correctness,practicability and reliability of power supply system as well as the digital control algorithm are verified.The results provide a new idea for the control of accelerator magnet power supply. 展开更多
关键词 Closed-loop control algorithm Load time constant Superconducting magnets three-branch structure
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