The present paper aims to reveal the significance of rigid-body motions for the flutter mechanism of a span-morphing wing model. The inclusion of rigid-body motions into aeroelastic formulation and flutter analysis is...The present paper aims to reveal the significance of rigid-body motions for the flutter mechanism of a span-morphing wing model. The inclusion of rigid-body motions into aeroelastic formulation and flutter analysis is presented. A state-space aeroelastic equation combining the dynamics of stepped Euler-Bernoulli beam with unsteady strip aerodynamic theory is developed by quasi-static modeling. Using a numerical example, variations of flutter mechanism from the bending-torsional flutter to the body-freedom flutter are observed as the span increases. In addition,effects of some dimensionless parameters on the variations of flutter mechanism are investigated.The investigated parameters belonging to the fuselage have limited influences on the bendingtorsional flutter but a significant impact on the body-freedom flutter.展开更多
为解决颤振控制TMD(tuned mass damper)设计时更准确地获取拟控制桥梁动力特性的问题,基于Sherman Morrison公式、拟控制桥梁的频响函数以及TMD参数,推导桥梁-TMD耦合系统的模态频率和阻尼。基于航空领域的颤振裕度法,推导两自由度弯扭...为解决颤振控制TMD(tuned mass damper)设计时更准确地获取拟控制桥梁动力特性的问题,基于Sherman Morrison公式、拟控制桥梁的频响函数以及TMD参数,推导桥梁-TMD耦合系统的模态频率和阻尼。基于航空领域的颤振裕度法,推导两自由度弯扭耦合气弹系统附加扭转TMD之后的颤振裕度随风速变化的表达式。提出了一种基于颤振裕度的TMD优化设计方法,以最大化颤振临界风速(颤振裕度等于0)为目标,得到TMD的优化参数。基于一个两自由度桥梁截面数值例子,对比分析了颤振裕度法和传统复特征值法所预测的耦合系统颤振临界风速和最优TMD参数,探讨了基于颤振裕度法的TMD优化设计方法的准确性,对比分析了控制前后4个风速下的时域响应,探讨了最优TMD的控制效果。研究结果表明:颤振裕度法和复特征值法两者计算得到的TMD最优参数一致,基于颤振裕度法预测的桥梁-最优TMD系统的颤振临界风速与基于复特征值法预测的结果仅存在2.2%的误差,且用最优TMD控制后桥梁颤振临界风速提高了50%。研究结果为桥梁颤振控制TMD的优化设计提供了一种新的方法。该方法所使用的频响函数包含了结构和气动力信息,依据应用场景不同,其可以是数值计算的频率响应函数,也可以是实测的频响函数。在实际应用中可通过大型激振器进行实验模态分析测试得到,其更加准确地表征了拟控制桥梁的动力特性,为TMD的精准设计奠定了基础。该方法的实际工程应用值得进一步发展和研究。展开更多
文摘The present paper aims to reveal the significance of rigid-body motions for the flutter mechanism of a span-morphing wing model. The inclusion of rigid-body motions into aeroelastic formulation and flutter analysis is presented. A state-space aeroelastic equation combining the dynamics of stepped Euler-Bernoulli beam with unsteady strip aerodynamic theory is developed by quasi-static modeling. Using a numerical example, variations of flutter mechanism from the bending-torsional flutter to the body-freedom flutter are observed as the span increases. In addition,effects of some dimensionless parameters on the variations of flutter mechanism are investigated.The investigated parameters belonging to the fuselage have limited influences on the bendingtorsional flutter but a significant impact on the body-freedom flutter.
文摘为解决颤振控制TMD(tuned mass damper)设计时更准确地获取拟控制桥梁动力特性的问题,基于Sherman Morrison公式、拟控制桥梁的频响函数以及TMD参数,推导桥梁-TMD耦合系统的模态频率和阻尼。基于航空领域的颤振裕度法,推导两自由度弯扭耦合气弹系统附加扭转TMD之后的颤振裕度随风速变化的表达式。提出了一种基于颤振裕度的TMD优化设计方法,以最大化颤振临界风速(颤振裕度等于0)为目标,得到TMD的优化参数。基于一个两自由度桥梁截面数值例子,对比分析了颤振裕度法和传统复特征值法所预测的耦合系统颤振临界风速和最优TMD参数,探讨了基于颤振裕度法的TMD优化设计方法的准确性,对比分析了控制前后4个风速下的时域响应,探讨了最优TMD的控制效果。研究结果表明:颤振裕度法和复特征值法两者计算得到的TMD最优参数一致,基于颤振裕度法预测的桥梁-最优TMD系统的颤振临界风速与基于复特征值法预测的结果仅存在2.2%的误差,且用最优TMD控制后桥梁颤振临界风速提高了50%。研究结果为桥梁颤振控制TMD的优化设计提供了一种新的方法。该方法所使用的频响函数包含了结构和气动力信息,依据应用场景不同,其可以是数值计算的频率响应函数,也可以是实测的频响函数。在实际应用中可通过大型激振器进行实验模态分析测试得到,其更加准确地表征了拟控制桥梁的动力特性,为TMD的精准设计奠定了基础。该方法的实际工程应用值得进一步发展和研究。
