气垫船导管后支撑振动疲劳影响因素研究

Effect Factor Analysis of Vibration Fatigue of Conduit Rear Support for Hovercraft

气垫船优越的两栖性和快速性使其在军事和民用领域均有不可替代的优势,但是气垫船严酷的振动问题一直没有得到很好的解决,振动故障频发。本文以某型气垫船空气导管后支撑为研究对象,首先基于频域功率谱密度法计算某工况下导管后支撑外接头振动疲劳寿命;然后从降低振动响应和提高疲劳性能2个方向,分别研究激励、模态阻尼比、固有频率、材料的疲劳性能对振动疲劳寿命的影响。结果表明:低阶模态对振动疲劳寿命影响显著,降低振动激励、提高阻尼比和提升疲劳性能均可以有效提升振动疲劳寿命,而调整固有频率不适用于平直功率谱加载方式;最后提出薄壁结构可通过局部加强来提高振动疲劳寿命的方法,并以一种加强手段验证其可行性。

The superior amphibious and rapidity of hovercraft make it play a crucial role in both military and civil field.However, the serious problem about vibration has not been solved, and which lead to several trouble. This paper takes the rear support the air duct of hovercraft as the research object. Firstly, the vibration fatigue life of the outer joint of the tube rear support was calculated based on the frequency domain power spectral density method. Then, from reducing vibration response and enhancing performance of fatigue analyses the effect of excitation, modal damping ratio, natural frequency and material fatigue properties, respectively. The result show that low-order modal contributes greatly to the fatigue life. Vibration fatigue life can be improved by reducing excitation, improving the modal damping ratio and the performance of material,except changing the natural frequency. Then, a method, local strengthening, about increasing fatigue life of thin-wall structure has been raised, and which has been proved by a simple case.