本文将杠杆型非线性能量阱(Lever-Type Nonlinear Energy Sink, LNES)耦合到复合材料层合梁的中点位置,研究了LNES对梁的横向振动抑制性能。结合牛顿第二运动定律和广义哈密顿原理,推导了耦合系统的动力学方程。采用伽辽金截断法离散耦...本文将杠杆型非线性能量阱(Lever-Type Nonlinear Energy Sink, LNES)耦合到复合材料层合梁的中点位置,研究了LNES对梁的横向振动抑制性能。结合牛顿第二运动定律和广义哈密顿原理,推导了耦合系统的动力学方程。采用伽辽金截断法离散耦合系统的偏微分控制方程,并通过龙格–库塔法获得近似数值解,验证了谐波平衡法得到的近似解析解。对比在相同幅值激励下耦合NES系统的响应曲线,发现LNES对系统的振动抑制效果更为优越。此外,讨论了LNES单一参数变化对系统幅频响应曲线的影响。根据结果确定,LNES对复合材料层合梁的横向振动有着显著的振动抑制效果。展开更多
Air-coupled ultrasonic transducers are used to generate and receive Lamb waves in quasi-isotropic laminated composite beams for delamination detection. The influence of incident angle on the excited mode is studied. N...Air-coupled ultrasonic transducers are used to generate and receive Lamb waves in quasi-isotropic laminated composite beams for delamination detection. The influence of incident angle on the excited mode is studied. Numerical calculation and experimental results show that a pure Lamb wave mode can be generated if the transmitting transducer is oriented at a specific angle, and the receiving transducer can either be oriented to detect the same mode as that generated by the transmitter or to detect another mode generated by mode conversion at a defect. A three-dimensional finite element model is created to predict the interaction of Lamb waves with delamination, and some unique mechanisms of interaction between A0 mode Lamb waves and delamination are revealed in detail. The experimental results obtained on laminated composite beam using air-coupled ultrasonic transducers are well in accordance with finite element simulation results. Research results show that air-coupled ultrasonic guided waves can be used for delamination damage detection effectively in laminated composite beams.展开更多
文摘本文将杠杆型非线性能量阱(Lever-Type Nonlinear Energy Sink, LNES)耦合到复合材料层合梁的中点位置,研究了LNES对梁的横向振动抑制性能。结合牛顿第二运动定律和广义哈密顿原理,推导了耦合系统的动力学方程。采用伽辽金截断法离散耦合系统的偏微分控制方程,并通过龙格–库塔法获得近似数值解,验证了谐波平衡法得到的近似解析解。对比在相同幅值激励下耦合NES系统的响应曲线,发现LNES对系统的振动抑制效果更为优越。此外,讨论了LNES单一参数变化对系统幅频响应曲线的影响。根据结果确定,LNES对复合材料层合梁的横向振动有着显著的振动抑制效果。
基金supported by the National Natural Science Foundation of China(Grant Nos. 11272021 and 50975006)Beijing Natural Science Foundation(Grant No. 1122007)+1 种基金the Importation and Development of High-Caliber Talents Project of Beijing Municipal Institutions(No.CIT&TCD201304048)Beijing Nova Program(Grant No. 2008A015)
文摘Air-coupled ultrasonic transducers are used to generate and receive Lamb waves in quasi-isotropic laminated composite beams for delamination detection. The influence of incident angle on the excited mode is studied. Numerical calculation and experimental results show that a pure Lamb wave mode can be generated if the transmitting transducer is oriented at a specific angle, and the receiving transducer can either be oriented to detect the same mode as that generated by the transmitter or to detect another mode generated by mode conversion at a defect. A three-dimensional finite element model is created to predict the interaction of Lamb waves with delamination, and some unique mechanisms of interaction between A0 mode Lamb waves and delamination are revealed in detail. The experimental results obtained on laminated composite beam using air-coupled ultrasonic transducers are well in accordance with finite element simulation results. Research results show that air-coupled ultrasonic guided waves can be used for delamination damage detection effectively in laminated composite beams.
