N-1型多面体夹芯结构体胞演化机理与性能正向设计

Evolution Mechanism of Unit Cell and Performance Forward Design of N-1 Type Polyhedral Sandwich Structure

N-1型多面体夹芯结构是一种新型的三明治类夹芯结构,具有比强度高、耐热性好、抗冲击等特性。针对N-1型多面体夹芯结构性能优化过程中,由于设计机理不明导致设计空间复杂、优化计算量大、优化结果局部最优等问题,提出基于体胞演化机理的N-1型多面体夹芯结构剪切性能正向设计。对N-1型正则多面体体胞进行几何特征分析,定义基础体胞及演化基础圆,将N-1型正则多面体体胞分为相切体胞、外相交体胞和内相交体胞。提出基于演化基础圆和基础体胞的N-1型多面体体胞相似演化模式,揭示体胞平面拓扑到空间拓扑演化机理,通过求解演化参数可行域,建立体胞演化叠合成形窗口。分析演化参数及板厚对N-1型多面体夹芯结构剪切性能的影响,确定N-1型多面体夹芯结构剪切性能空间分布及优化空间域。在此基础上,建立基于Kriging近似技术的多面体夹芯结构剪切性能优化模型,正向优化得到剪切性能全局最优的N-1型多面体夹芯板。最后,通过与瓦楞夹芯结构比较,验证了该结构的可靠性,为设计正则多面体夹芯结构提供理论依据。

N-1 type polyhedral sandwich structure is a kind of sandwich structure which has the advantages of high specific strength,good heat resistance and impact resistance.In the process of structure optimization,the complexity of design space and calculation lead to local optimum results.In order to solve this problem,forward design method for shear performance of N-1 type polyhedral sandwich structure based on the evolution mechanism of unit cell is proposed.Firstly,the geometric feature of N-1 type polyhedral unit cell is analyzed.The fundamental cells and evolutionary circles are defined.N-1 type polyhedral unit cells were divided into tangent cells,outer intersected cells and inner intersected cells.Secondly,the similarity evolution pattern of N-1 type polyhedral unit cell is constructed based on basic cell and evolutionary circles.The evolution mechanisms between 2 D topology and 3 D topology is obtained.And the feasible windows of unit cell evolution are put forward by calculating the feasible domain of evolution parameters.Thirdly,optimization domain and spatial distribution of N-1 type polyhedral sandwich structure shear performance are determined by analyzing the relationship between evolution parameters,thickness and shear properties.Then,the optimization model for shear performance of N-1 type polyhedral sandwich structure is established based on the Kriging approximation technique and obtained the N-1 polyhedral sandwich panel with globally optimal shear performance.Finally,the reliability of the structure is verified by comparison with the corrugated sandwich structure,which provides a theoretical basis for designing the regular polyhedral sandwich structure.