In this paper,a type of reinforcing structure for composite shell with single and through hole is presented.The experimental tests for the composite shells without hole,with single hole and reinforced structure,with t...In this paper,a type of reinforcing structure for composite shell with single and through hole is presented.The experimental tests for the composite shells without hole,with single hole and reinforced structure,with through hole and reinforced structure subjected to hydrostatic pressure were carried out by the designed experimental test system.The mechanical responses of the composite shells under hydrostatic pressure are obtained by the high-speed camera and strain measurement.The results show that the entire deformation process of the shell can be divided into three:uniform compression,"buckling mode formation"and buckling.The"buckling mode formation"process is captured and reported for the first time.For the composite shell with single hole,the proposed reinforcing structure has a significant reinforcement effect on the shell and the buckling capacity of the shell is not weaker than the complete composite shell.For the composite shell with through hole,sealing effect can be achieved by the proposed reinforcing structure,but the buckling capacity of the shell after reinforcement can only reach 77%of the original buckling capacity.展开更多
The initial geometric imperfection is one of the primary factors affecting the buckling behaviors of composite cylindrical shells under hydrostatic pressure.In this study,ovality and thickness variations as two repres...The initial geometric imperfection is one of the primary factors affecting the buckling behaviors of composite cylindrical shells under hydrostatic pressure.In this study,ovality and thickness variations as two representative types of the geometric imperfections are considered.After measuring the geometric imperfections,a typical carbon fiber reinforced polymers(CFRP)cylindrical shell is tested to obtain the buckling pressure.The buckling behaviors of the shell sample are analyzed in combination with the strain responses.By using the nonlinear numerical analysis,the buckling shapes of the CFRP cylinder shells with different combinations of ovality and thickness variation are firstly discussed.The rules of influence of such imperfections on the buckling pressure are then obtained by nonlinear regression method.Finally,an empirical formula is proposed to predict the buckling pressure of the composite cylinder shells,and the calculated results from the formula are in good agreement with the numerical results.展开更多
为了提高光纤水听器在深海环境中检测声波的灵敏度,设计了一种基于推挽式结构的深海光纤水听器基元,可以实现深海3000 m处10 Hz~2 kHz目标水声信号的有效探测。首先,基于Michelson干涉仪介绍推挽式深海光纤水听器的构成与声压灵敏度理论...为了提高光纤水听器在深海环境中检测声波的灵敏度,设计了一种基于推挽式结构的深海光纤水听器基元,可以实现深海3000 m处10 Hz~2 kHz目标水声信号的有效探测。首先,基于Michelson干涉仪介绍推挽式深海光纤水听器的构成与声压灵敏度理论,接着利用弹性力学理论分析声压转换机理,通过有限元方法模拟仿真水听器探头的弹性筒结构尺寸参数对声压灵敏度的影响,并针对水听器在深水环境下工作的稳定性进行了探究。根据计算结果分别制作了5组不同结构和制作工艺的光纤水听器基元。最后,通过高静水压灵敏度系统测试,模拟5组光纤水听器在深海3000 m处的工作性能,验证水听器弹性筒的结构参数和制作工艺对其在深海环境中声压灵敏度的影响。实验结果显示,光纤水听器基元的结构和制作工艺可以显著地影响其在深海环境中工作性能和稳定性,经过结构参数和制作工艺优化后的光纤水听器在深海3000 m处10 Hz~2 kHz频带范围下的水声信号的响应,其平均声压灵敏度可达到-127 dB re rad/µPa,相比优化前提高了7 dB re rad/µPa。综上所述,优化后的水听器基本满足深海高静水压下声波的高灵敏可靠探测要求。展开更多
基金supported by the Ningbo Major Research and Development Plan Project(Grant No.2024Z135)the Natural Science Basic Research Program of Shaanxi Province(Grant No.2024JC-YBMS-322)+1 种基金China Postdoctoral Science Foundation(Grant No.2020M673492)National Natural Science Foundation of China(Grant No.51909219)。
文摘In this paper,a type of reinforcing structure for composite shell with single and through hole is presented.The experimental tests for the composite shells without hole,with single hole and reinforced structure,with through hole and reinforced structure subjected to hydrostatic pressure were carried out by the designed experimental test system.The mechanical responses of the composite shells under hydrostatic pressure are obtained by the high-speed camera and strain measurement.The results show that the entire deformation process of the shell can be divided into three:uniform compression,"buckling mode formation"and buckling.The"buckling mode formation"process is captured and reported for the first time.For the composite shell with single hole,the proposed reinforcing structure has a significant reinforcement effect on the shell and the buckling capacity of the shell is not weaker than the complete composite shell.For the composite shell with through hole,sealing effect can be achieved by the proposed reinforcing structure,but the buckling capacity of the shell after reinforcement can only reach 77%of the original buckling capacity.
基金supported by the National Natural Science Foundation of China(Grant No.51909219)the National Key Research and Development Program of China(Grant No.2016YFC0301300)+1 种基金Fundamental Research Funds for the Central Universities(Grant No.3102019JC006)China Postdoctoral Science Foundation(Grand No.2020M673492)。
文摘The initial geometric imperfection is one of the primary factors affecting the buckling behaviors of composite cylindrical shells under hydrostatic pressure.In this study,ovality and thickness variations as two representative types of the geometric imperfections are considered.After measuring the geometric imperfections,a typical carbon fiber reinforced polymers(CFRP)cylindrical shell is tested to obtain the buckling pressure.The buckling behaviors of the shell sample are analyzed in combination with the strain responses.By using the nonlinear numerical analysis,the buckling shapes of the CFRP cylinder shells with different combinations of ovality and thickness variation are firstly discussed.The rules of influence of such imperfections on the buckling pressure are then obtained by nonlinear regression method.Finally,an empirical formula is proposed to predict the buckling pressure of the composite cylinder shells,and the calculated results from the formula are in good agreement with the numerical results.
文摘为了提高光纤水听器在深海环境中检测声波的灵敏度,设计了一种基于推挽式结构的深海光纤水听器基元,可以实现深海3000 m处10 Hz~2 kHz目标水声信号的有效探测。首先,基于Michelson干涉仪介绍推挽式深海光纤水听器的构成与声压灵敏度理论,接着利用弹性力学理论分析声压转换机理,通过有限元方法模拟仿真水听器探头的弹性筒结构尺寸参数对声压灵敏度的影响,并针对水听器在深水环境下工作的稳定性进行了探究。根据计算结果分别制作了5组不同结构和制作工艺的光纤水听器基元。最后,通过高静水压灵敏度系统测试,模拟5组光纤水听器在深海3000 m处的工作性能,验证水听器弹性筒的结构参数和制作工艺对其在深海环境中声压灵敏度的影响。实验结果显示,光纤水听器基元的结构和制作工艺可以显著地影响其在深海环境中工作性能和稳定性,经过结构参数和制作工艺优化后的光纤水听器在深海3000 m处10 Hz~2 kHz频带范围下的水声信号的响应,其平均声压灵敏度可达到-127 dB re rad/µPa,相比优化前提高了7 dB re rad/µPa。综上所述,优化后的水听器基本满足深海高静水压下声波的高灵敏可靠探测要求。
