【摘要】 该文发展了时变附加质量方法,并利用有限元方法模拟了水下飞行器的出水过程。基于出水过程中飞行器的振动模态试验数据,由于出水长度与一阶横向振动频率、出水长度与附加质量均有一一对应关系,所以该文在一定假设条件下,通过反演方法得到了随出水长度变化的横向时变附加质量,初步形成了将复杂流场载荷向飞行器表面等效的方法。该文完成了对水下飞行器出水过程动态性能的研究,考察了某截面上弯矩和剪力随时间变化的情况。在附加质量的影响下,结构的响应频率会低于无附加质量的情况,而响应幅值则因不同的外载荷条件而异。随着出水长度的增加和沾湿长度的减少,结构的振动频率逐渐升高,此计算结果也定性地说明了时变附加质量的合理性,并为对附加质量方法作进一步研究奠定了基础。更多还原

【Abstract】 A finite element method based on the added mass method is presented to simulate the water-exit process of an underwater vehicle.Starting from the modal experimental data of vibration in the water-exit process,transient distributions of added mass on the structure are derived from the frequencies of transverse vibrations.The dynamic behavior of the underwater vehicle during the water-exit process is studied.Investigations are carried out upon the transient response of the bending moment and transverse force on some key cross-sections.In contrast to the situation where there is no added mass,the frequencies are lower with the added mass.However,the magnitude of vibrations is not the case.Frequencies grow as the water-exit length grows in the computations.This result qualitatively validates the time-varying transverse added mass method and lays the foundation of further research on the added-mass-based FEM.更多还原