基于概率神经网络的航天结构响应映射预示方法

Method for response mapping prediction of aerospace structures based on probabilistic neural network

  • 摘要: 为更好地利用地面试验数据预示飞行器在真实飞行状态下的动力学环境,考虑到复杂航天结构非线性动力学特性和响应数据中的不确定性,提出一种基于概率神经网络(probabilistic neural network, PNN)的响应映射预示方法。首先给出分布载荷下响应映射预示方法的理论基础,表明映射关系的建立与载荷源数目无关;然后分析引入PNN来建立映射关系的必要性,并重点介绍PNN方法进行响应预示的算法;最后利用某飞行器仪器舱噪声试验对所提方法进行验证,结果表明PNN方法在不同载荷量级、全频段均具有良好的预示精度。此外,分析了噪声激励下仪器舱结构的非线性动力学特性,结果表明PNN方法较矩阵映射法具有更加优异的预示精度。文章将确定性映射预示方法推广到概率映射预示方法,提高了映射预示方法的可信度和工程实用性。

     

    Abstract: To improve the utilization of ground test data in predicting the dynamic environment of aircraft during flight, a response mapping prediction method based on a probabilistic neural network (PNN) was proposed, taking into account the nonlinear dynamic characteristics of complex aerospace structures and the uncertainties contained in response data. Firstly, the theoretical basis of the response mapping prediction method under distributed load was given, indicating that the establishment of the mapping relationship was independent of the number of load sources. Then, the necessity of introducing PNN to establish mapping relationship was analyzed, and the specific details of using the PNN method for response prediction were emphasized. Finally, the proposed method was verified by a noise test of an instrument cabin. The results showed that the PNN method has good prediction accuracy in different load levels and full-frequency bands. In addition, the nonlinear dynamic characteristics of the instrument cabin under noise excitation were analyzed. The results showed that the PNN method has better prediction accuracy than the matrix mapping method. This paper extends the deterministic mapping prediction method to the probabilistic mapping prediction method, which improves the credibility and engineering practicality of the mapping prediction method.

     

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