W_(45)Cu_(55),Cr_(65)Cu_(35),and Cr_(32)W_(14)Cu_(54)alloys were obtained in order to study the mechanism of“smart response”of the structure of these alloys when using them as arc-resistant circuit-breakers.These al...W_(45)Cu_(55),Cr_(65)Cu_(35),and Cr_(32)W_(14)Cu_(54)alloys were obtained in order to study the mechanism of“smart response”of the structure of these alloys when using them as arc-resistant circuit-breakers.These alloys differ from industrial ones with frameless packing of Cr and W phases in the copper matrix.The alloy production method is based on the infiltration of copper melt into a mixture of non-compacted Cr and W powders under vibration exposure(80 Hz).The research results show an increase in the arc resistance of contacts when changing from“frame”packing of W to“frameless,”as well as the decisive role of Cr in the processes of self-dispersion of arc-resistant phases and passivation of W and Cu.Based on the obtained results,conclusions are drawn about the advantage of frameless packing of arc-resistant phases in copper and the reasons for the“smart behavior”of the structure of Cr-containing contacts in response to functional loads in the presence of oxygen and an inert atmosphere.展开更多
压电智能结构的模型难以精确建立,且存在外界环境激励干扰和内部参数不确定等问题,从而影响闭环结构的振动控制性能。基于此,将结构的内部干扰和外界激励的影响归结为系统的集总干扰,并利用扩张状态观测器(Extended state observer,ESO...压电智能结构的模型难以精确建立,且存在外界环境激励干扰和内部参数不确定等问题,从而影响闭环结构的振动控制性能。基于此,将结构的内部干扰和外界激励的影响归结为系统的集总干扰,并利用扩张状态观测器(Extended state observer,ESO)设计不依赖于模型的自抗扰振动控制器。然而当外界扰动激励变化时,扩张状态观测器对扰动和各阶状态的估计不可避免存在偏差,难以保证振动控制的效果。为克服二阶自抗扰策略在振动主动控制中的不足,提出一种基于压电智能板结构的状态估计误差补偿自抗扰振动控制方案。利用状态观测误差信息,对二阶自抗扰控制器进行补偿,从而减小ESO对扰动和各阶状态估计的压力,提高振动控制效果。利用dSPACE实时仿真系统,搭建四面固支压电智能板结构的振动主动试验平台。四种干扰激励的试验结果验证该方法的有效性、实用性和强抗干扰能力。展开更多
文摘W_(45)Cu_(55),Cr_(65)Cu_(35),and Cr_(32)W_(14)Cu_(54)alloys were obtained in order to study the mechanism of“smart response”of the structure of these alloys when using them as arc-resistant circuit-breakers.These alloys differ from industrial ones with frameless packing of Cr and W phases in the copper matrix.The alloy production method is based on the infiltration of copper melt into a mixture of non-compacted Cr and W powders under vibration exposure(80 Hz).The research results show an increase in the arc resistance of contacts when changing from“frame”packing of W to“frameless,”as well as the decisive role of Cr in the processes of self-dispersion of arc-resistant phases and passivation of W and Cu.Based on the obtained results,conclusions are drawn about the advantage of frameless packing of arc-resistant phases in copper and the reasons for the“smart behavior”of the structure of Cr-containing contacts in response to functional loads in the presence of oxygen and an inert atmosphere.
文摘为了对光纤进行金属嵌入式封装,对T2紫铜与1100(L4)纯铝进行了超声波焊接试验,在焊接过程中进行了光纤传感器的嵌入试验.嵌入的光纤传感器分别选用裸光纤、化学镀层保护光纤、化学镀+电镀层保护光纤,对嵌入效果进行了比较.采用拉伸试验的方法对嵌入强度进行了测试;采用光检测计检测了嵌入后的光强损失.结果表明,纯铝箔可以做为光纤传感器金属封装的基体材料;化学镀加电镀的方法可以作为光纤保护方法;电镀光纤超声嵌入铝箔后光强损失0.22 dB;金属化光纤嵌入铝箔拉伸力达到45 N.
文摘压电智能结构的模型难以精确建立,且存在外界环境激励干扰和内部参数不确定等问题,从而影响闭环结构的振动控制性能。基于此,将结构的内部干扰和外界激励的影响归结为系统的集总干扰,并利用扩张状态观测器(Extended state observer,ESO)设计不依赖于模型的自抗扰振动控制器。然而当外界扰动激励变化时,扩张状态观测器对扰动和各阶状态的估计不可避免存在偏差,难以保证振动控制的效果。为克服二阶自抗扰策略在振动主动控制中的不足,提出一种基于压电智能板结构的状态估计误差补偿自抗扰振动控制方案。利用状态观测误差信息,对二阶自抗扰控制器进行补偿,从而减小ESO对扰动和各阶状态估计的压力,提高振动控制效果。利用dSPACE实时仿真系统,搭建四面固支压电智能板结构的振动主动试验平台。四种干扰激励的试验结果验证该方法的有效性、实用性和强抗干扰能力。
