500m口径射电望远镜(Five-hundred-meter aperture spherical radio telescope,FAST)采用柔性索网+刚性面板的设计方案,变位观测过程中索网呈柔性,而面板单元则呈刚性,这就需要在面板和索网节点之间设计自适应连接机构,以避免面板在单...500m口径射电望远镜(Five-hundred-meter aperture spherical radio telescope,FAST)采用柔性索网+刚性面板的设计方案,变位观测过程中索网呈柔性,而面板单元则呈刚性,这就需要在面板和索网节点之间设计自适应连接机构,以避免面板在单元变位过程中受附加应力的影响。因应FAST的技术需求,主要完成了以下工作:进行自适应连接机构的自由度设计及机械设计,建立包含连接机构的FAST反射面整体有限元模型,并通过与理论分析结果的对比,验证了有限元模型的准确性;应用建立的有限元模型,计算索网在变位过程中自适应连接机构的运动范围,为FAST工程提供了必要的设计参数。展开更多
In order to overcome the shortcoming of space-borne rigid antenna reflector made of carbon fiber reinforced plastic(CFRP)skins with aluminum honeycomb sandwich(SAHS)structure,a new type of full CFRP skin plus rib(SPR)...In order to overcome the shortcoming of space-borne rigid antenna reflector made of carbon fiber reinforced plastic(CFRP)skins with aluminum honeycomb sandwich(SAHS)structure,a new type of full CFRP skin plus rib(SPR)structure ring-focused parabolic surface antenna reflector with the size of 2.5 m×1.9 m is designed.Under the condition that the original caliber,surface type,and interface remain unchanged,the main influence factors are designed and controlled.First,from the perspective of high stiffness,lightweight,and easy to form,a finite element simulation software is used to analyze and optimize the layout of the rib,the cross-sectional shape of the rib,the size of the rib,and the matching of the size and the coefficients of thermal expansion(CTEs)of the rib and the skin.Second,two structures are prepared by the autoclave molding process.Third,the weight and the surface precision root mean square(RMS)value are measured.The results show that the fundamental frequency of the SPR structure is 142.2 Hz,which is 3.5 Hz higher;the number of the new structural parts is reduced by 40%,and the forming process is greatly simplified.The total weight of the new structure is 11.9 kg,lighter 42.5%,indicating that the weight loss is obvious.The RMS value is 0.15 mm,which is slightly lower 0.01 mm but satisfies the accuracy requirement not greater than 0.3 mm.It is proved that the SPR structure reflector is a superior structure of the lightweight spaceborne antenna reflector.展开更多
该文介绍了500m口径球面射电望远镜(fivehundred-meter aperture spherical radio telescope,FAST)反射面单元的组成和工作原理。对三角形单元的滑动故障和结构损伤原因进行了力学建模与分析,提出了免于故障和损伤的改进建议,包括3种自...该文介绍了500m口径球面射电望远镜(fivehundred-meter aperture spherical radio telescope,FAST)反射面单元的组成和工作原理。对三角形单元的滑动故障和结构损伤原因进行了力学建模与分析,提出了免于故障和损伤的改进建议,包括3种自适应连接机构的新型布局、反射面单元故障判断方法和自适应连接机构设计改进等。该文力学模型可以帮助望远镜维护人员分析三角形反射面单元故障和损伤的主要原因,预测故障发生模式和可能发生故障的危险单元分布位置,从而有针对性地进行改进。该文有助于望远镜维护人员在日常巡检中通过目测手段,及时发现反射面单元的异常现象,防止问题继续恶化,有利于未来设备维护和更换。展开更多
文摘500m口径射电望远镜(Five-hundred-meter aperture spherical radio telescope,FAST)采用柔性索网+刚性面板的设计方案,变位观测过程中索网呈柔性,而面板单元则呈刚性,这就需要在面板和索网节点之间设计自适应连接机构,以避免面板在单元变位过程中受附加应力的影响。因应FAST的技术需求,主要完成了以下工作:进行自适应连接机构的自由度设计及机械设计,建立包含连接机构的FAST反射面整体有限元模型,并通过与理论分析结果的对比,验证了有限元模型的准确性;应用建立的有限元模型,计算索网在变位过程中自适应连接机构的运动范围,为FAST工程提供了必要的设计参数。
文摘In order to overcome the shortcoming of space-borne rigid antenna reflector made of carbon fiber reinforced plastic(CFRP)skins with aluminum honeycomb sandwich(SAHS)structure,a new type of full CFRP skin plus rib(SPR)structure ring-focused parabolic surface antenna reflector with the size of 2.5 m×1.9 m is designed.Under the condition that the original caliber,surface type,and interface remain unchanged,the main influence factors are designed and controlled.First,from the perspective of high stiffness,lightweight,and easy to form,a finite element simulation software is used to analyze and optimize the layout of the rib,the cross-sectional shape of the rib,the size of the rib,and the matching of the size and the coefficients of thermal expansion(CTEs)of the rib and the skin.Second,two structures are prepared by the autoclave molding process.Third,the weight and the surface precision root mean square(RMS)value are measured.The results show that the fundamental frequency of the SPR structure is 142.2 Hz,which is 3.5 Hz higher;the number of the new structural parts is reduced by 40%,and the forming process is greatly simplified.The total weight of the new structure is 11.9 kg,lighter 42.5%,indicating that the weight loss is obvious.The RMS value is 0.15 mm,which is slightly lower 0.01 mm but satisfies the accuracy requirement not greater than 0.3 mm.It is proved that the SPR structure reflector is a superior structure of the lightweight spaceborne antenna reflector.
文摘该文介绍了500m口径球面射电望远镜(fivehundred-meter aperture spherical radio telescope,FAST)反射面单元的组成和工作原理。对三角形单元的滑动故障和结构损伤原因进行了力学建模与分析,提出了免于故障和损伤的改进建议,包括3种自适应连接机构的新型布局、反射面单元故障判断方法和自适应连接机构设计改进等。该文力学模型可以帮助望远镜维护人员分析三角形反射面单元故障和损伤的主要原因,预测故障发生模式和可能发生故障的危险单元分布位置,从而有针对性地进行改进。该文有助于望远镜维护人员在日常巡检中通过目测手段,及时发现反射面单元的异常现象,防止问题继续恶化,有利于未来设备维护和更换。
