囊式空气弹簧(convoluted air spring,CAS)的结构参数是影响其力学特性的重要因素,解决结构参数的辨识难题是计算囊式空气弹簧承载、刚度特性的关键途径。采用几何与力学分析方法,以单曲曲囊弧长和盖板有效法兰半径为关键设计参量,建立...囊式空气弹簧(convoluted air spring,CAS)的结构参数是影响其力学特性的重要因素,解决结构参数的辨识难题是计算囊式空气弹簧承载、刚度特性的关键途径。采用几何与力学分析方法,以单曲曲囊弧长和盖板有效法兰半径为关键设计参量,建立了基于关键设计参量的囊式空气弹簧统一结构参数预测模型。搭建了结构参数测试装置,试验验证了统一结构参数模型的正确性。揭示了CAS有效容积及其变化率、有效面积与关键设计参量均正相关,但有效面积变化率与曲囊弧长正相关、与有效法兰半径呈负线性相关特性,为设计刚度更低的CAS提供指导;进一步指出有效法兰半径对CAS结构参数的影响比曲囊弧长更为显著,增大有效法兰半径能够明显增大有效面积而显著提升CAS的承载特性,为保证工作气压不变前提下提升CAS承载能力提供了设计指引。研究结果为设计阶段准确计算囊式空气弹簧的结构参数、力学特性奠定基础,也为其结构参数设计与优化提供理论支撑。展开更多
A surrogate-model-based aerodynamic optimization design method for cycloidal propeller in hover was proposed,in order to improve its aerodynamic efficiency,and analyze the basic criteria for its aerodynamic optimizati...A surrogate-model-based aerodynamic optimization design method for cycloidal propeller in hover was proposed,in order to improve its aerodynamic efficiency,and analyze the basic criteria for its aerodynamic optimization design.The reliability and applicability of overset mesh method were verified.An optimization method based on Kriging surrogate model was proposed to optimize the geometric parameters for cycloidal propeller in hover with the use of genetic algorithm.The optimization results showed that the thrust coefficient was increased by 3.56%,the torque coefficient reduced by 12.05%,and the figure of merit(FM)increased by 19.93%.The optimization results verified the feasibility of this design idea.Although the optimization was only carried out at a single rotation speed,the aerodynamic efficiency was also significantly improved over a wide range of rotation speeds.The optimal configuration characteristics for micro and small-sized cycloidal propeller were:solidity of 0.2-0.22,maximum pitch angle of 25°-35°,pitch axis locating at 35%-45% of the blade chord length.展开更多
文摘囊式空气弹簧(convoluted air spring,CAS)的结构参数是影响其力学特性的重要因素,解决结构参数的辨识难题是计算囊式空气弹簧承载、刚度特性的关键途径。采用几何与力学分析方法,以单曲曲囊弧长和盖板有效法兰半径为关键设计参量,建立了基于关键设计参量的囊式空气弹簧统一结构参数预测模型。搭建了结构参数测试装置,试验验证了统一结构参数模型的正确性。揭示了CAS有效容积及其变化率、有效面积与关键设计参量均正相关,但有效面积变化率与曲囊弧长正相关、与有效法兰半径呈负线性相关特性,为设计刚度更低的CAS提供指导;进一步指出有效法兰半径对CAS结构参数的影响比曲囊弧长更为显著,增大有效法兰半径能够明显增大有效面积而显著提升CAS的承载特性,为保证工作气压不变前提下提升CAS承载能力提供了设计指引。研究结果为设计阶段准确计算囊式空气弹簧的结构参数、力学特性奠定基础,也为其结构参数设计与优化提供理论支撑。
文摘A surrogate-model-based aerodynamic optimization design method for cycloidal propeller in hover was proposed,in order to improve its aerodynamic efficiency,and analyze the basic criteria for its aerodynamic optimization design.The reliability and applicability of overset mesh method were verified.An optimization method based on Kriging surrogate model was proposed to optimize the geometric parameters for cycloidal propeller in hover with the use of genetic algorithm.The optimization results showed that the thrust coefficient was increased by 3.56%,the torque coefficient reduced by 12.05%,and the figure of merit(FM)increased by 19.93%.The optimization results verified the feasibility of this design idea.Although the optimization was only carried out at a single rotation speed,the aerodynamic efficiency was also significantly improved over a wide range of rotation speeds.The optimal configuration characteristics for micro and small-sized cycloidal propeller were:solidity of 0.2-0.22,maximum pitch angle of 25°-35°,pitch axis locating at 35%-45% of the blade chord length.