机翼气动弹性的随机不确定性分析研究  

Random uncertainty of aeroelastic system

作　　者：宋述芳[1] 吕震宙[1] 张伟伟[2] 叶正寅[2] 乔红威[1] 

机构地区：[1]西北工业大学航空学院,陕西西安710072 [2]西北工业大学翼型叶栅空气动力学国防科技重点实验室,陕西西安710072

出　　处：《振动工程学报》2009年第3期227-231,共5页Journal of Vibration Engineering

基　　金：国家自然科学基金(10572117;50875213;10802063);新世纪优秀人才支持计划(05-0868);航空基础基金(2007ZA53012);西北工业大学博士论文创新基金(CX200801)资助项目

摘　　要：通过分析气动弹性状态方程的特征值来求解颤振临界速度,并建立颤振的安全裕度方程。针对带有操纵面机构的二元三自由度机翼颤振问题,分别采用重要抽样法和线抽样可靠性分析技术,在d维标准正态空间中对飞机机翼的气动弹性问题进行失效概率和灵敏性分析,推导得出反映随机参数对失效概率影响程度的灵敏度因子,在假设条件下的分析结果表明了模型尺寸、质量比等对颤振可靠性的影响很小,故在进一步的计算中认为它们是确定量,仅考虑固有频率为随机变量情况下的不确定性分析。以重要抽样法的结果为近似精确解,验证了线抽样不确定性分析方法的正确性和高效性。An effective numerical simulation method for reliability, line sampling technique, is proposed to analyze the probability and sensitivity characteristics of flutter with structural random parameters. By computing the eigenvalues of the state equations of aeroelastic system, the flutter characteristics can be analyzed. The safety margin of flutter is founded by using of flutter critical velocity. The partial derivatives of the failure probability with respect to the random parameters are derived in detail, which can describe the effect of random parameters on the failure probability quantificationally, so it can guide the structural optimization design. And then considering a two-dimensional three-degrees of freedom airplane wing with aileron as the calculation model of flutter, importance sampling （IS） method and line sampling technique （LST） are used to analyze the randomness uncertainty of flutter. The results show that the random variables of frequency have more significant effects on the flutter reliability than the struetural size and mass ratio. Then the reliability of the wing flutter is analyzed with the randomness of frequency. Considering the results of importance sampling as the approximately exact ones, the results of LST are agreed with the exact ones. The computational efficiency of LST is improved greatly than that of IS method.

关 键 词：气动弹性 颤振 线抽样技术 重要抽样法 安全裕度 

分 类 号：TB114.3[理学—概率论与数理统计] V215.3[理学—数学]