热过屈曲功能梯度壁板的气动弹性颤振

发布时间：2019-02-25 18:00

【摘要】：功能梯度材料的宏观物理性能随空间位置连续变化,能充分减少不同组份材料结合部位界面性能的不匹配因素.功能梯度壁板用作高速飞行器的热防护结构,能有效消除气动加热带来的壁板内部热应力集中.本文考虑热过屈曲变形引入的结构几何非线性,分析功能梯度壁板的气动弹性颤振边界.基于幂函数材料分布假设,采用混合定律计算功能梯度材料的等效力学性能.根据一阶剪切变形板理论、冯·卡门应变-位移关系和一阶活塞理论,基于虚功原理建立超声速气流中受热功能梯度壁板的非线性气动弹性有限元方程.采用牛顿-拉弗森迭代法数值求解壁板的热屈曲变形,分析超声速气流对热屈曲变形的影响机理.在壁板热过屈曲的静力平衡位置分析动态稳定性,确定了壁板的颤振边界.研究表明,当陶瓷-金属功能梯度壁板的组份材料沿厚度方向梯度分布时,会破坏结构的对称性导致壁板在面内热应力作用下发生指向金属侧的热屈曲变形.超声速气流中壁板热屈曲变形最大的位置随气流速压增大向下游推移,并伴随屈曲变形量的减小.热过屈曲壁板的几何非线性效应会提高壁板的颤振边界,这种影响在高温、低无量纲速压且壁板发生大挠度热屈曲变形时表现显著.较高无量纲气流速压下由于壁板的热屈曲变形被气动力限定在小挠度范围,几何非线性效应不明显.
[Abstract]:The macro-physical properties of the functionally graded materials vary continuously with the space position, which can reduce the mismatch factors of the interfacial properties of the bonding sites of the materials with different components. Functionally gradient panels are used as thermal protection structures for high-speed aircraft, which can effectively eliminate the thermal stress concentration in the panels caused by aerodynamic heating. In this paper, the Aeroelastic flutter boundary of functionally graded panels is analyzed by considering the geometric nonlinearity of the structure introduced by thermal post-buckling deformation. Based on the distribution hypothesis of power function materials, the equivalent mechanical properties of functionally graded materials are calculated by the law of mixing. Based on the first-order shear deformation plate theory, the von Carmen strain-displacement relationship and the first-order piston theory, the nonlinear Aeroelastic finite element equations for the thermal functionally gradient panels in supersonic flow are established based on the virtual work principle. Newton-Raphson iterative method is used to numerically solve the thermal buckling deformation of panels, and the mechanism of the influence of supersonic flow on thermal buckling deformation is analyzed. The dynamic stability is analyzed at the static equilibrium position of the thermal post-buckling of the panel, and the flutter boundary of the panel is determined. The results show that when the ceramic-metal functionally graded wall material is distributed along the thickness direction, the symmetry of the structure will be destroyed and the thermal buckling deformation of the wall plate pointing to the metal side will occur under the action of in-plane thermal stress. The maximum position of the thermal buckling deformation of the wall plate in supersonic flow moves downstream with the increase of the airflow pressure and decreases with the decrease of the buckling deformation. The geometric nonlinear effect of thermal post-buckling panels can improve the flutter boundary of the panels, which is significant at high temperature, low dimensionless fast pressure and large deflection thermal buckling deformation of the panels. Because the thermal buckling deformation of the panel is limited to a small deflection range by aerodynamic force at higher dimensionless gas velocity pressure, the geometric nonlinear effect is not obvious.
【作者单位】：西安交通大学航天航空学院机械结构强度与振动国家重点实验室;
【基金】：国家自然科学基金(11302162) 高等学校博士学科点专项科研基金(20110201120023) 陕西省自然科学基础研究计划(2013JQ1005)资助项目
【分类号】：O341

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