摘要
研究了航空拖曳式诱饵释放过程中的动态特性。根据诱饵的运动状态,将释放过程划分为自由状态、放索状态和拖曳状态。利用Kane方程建立了拖曳式诱饵释放的多体系统动力学模型,其中拖索离散为若干段刚性杆,诱饵视为刚体与拖索铰接,其上的作用力包括铰约束力、气动力和重力。针对放索过程中第1个索段质量时变引起的变质量动力学问题,采用Generalized-α算法进行时域求解。在此基础上分析了载机不同飞行高度、飞行速度、拖索释放速度以及拖曳点位置对诱饵释放过程中动态特性的影响。结果表明:在低空高速下释放,诱饵的俯仰角幅值较小,质心相对位置变化较稳定,收敛速度较快,但载机飞行速度过大时,诱饵容易靠近载机尾流区并受其影响;放索速度增大时,诱饵俯仰角幅值增大,质心会出现纵向沉浮运动;拖曳点远离重心时,俯仰角震荡幅值增大,当靠近重心时,收敛性变差,应合理设计并优化拖曳点位置和放索速度。
A study is presented of the dynamic characteristics of an aeronautic towed decoy during its release from an air- craft. The releasing process is divided into a falling stage, a releasing stage and a towing stage. A multi-body dynamic mod- el is built for the towed decoy system based on Kane＇s equation. In this instance, the cable is discretized into an arbitrary number of segments. The decoy is considered as a rigid body hanging from the cable. The cable and decoy＇s airloads are considered in the dynamic model, as well as the effects of the cable＇s motion. Numerical simulations of the dynamic charac- teristics in different conditions are conducted, and the results show that when the towed decoy is released at a high flight speed or altitude, the amplitude of the decoy＇s pitching angle decreases and the relative position of its gravity center varies smoothly. When the cable releasing speed rises, the amplitude of the decoy＇s pitching angle decreases and a longitudinal plunging motion of the gravity center occurs, but the releasing time is shortened. When the towed point is far away from the gravity center, the amplitude of the decoy＇s pitching angle increases. The rate of convergence becomes slow when the towed point is near the gravity center. This study may provide some reference for the design and working of towed decoys.
出处
《航空学报》
EI
CAS
CSCD
北大核心
2014年第7期1912-1921,共10页
Acta Aeronautica et Astronautica Sinica
基金
国家自然科学基金(91216102)
高等学校博士学科点专项科研基金(20131102120014)~~
关键词
拖曳式诱饵
释放
动态特性
多体动力学
KANE方程
towed decoy
release
dynamic characteristics
multi-body dynamics
Kane＇s equation
