The vibration environment prediction method based on OPAX

基于扩展工况传递路径分析的振动环境预计方法研究

Aircraft Strength Research Institute, Xi'an 710065, China

Received: 18 February 2022

Abstract

准确获得飞机结构及机载设备的振动环境至关重要, 传统的振动环境预计方法预计准确度低, 可能会导致后期振动环境试验过试验或欠试验的问题。创新性地提出了一种基于扩展工况传递路径分析(OPAX)的振动环境预计方法, 采用实测数据搭建振动环境预计模型, 再利用该模型对新工况下的振动环境进行预计。试验室环境下, 搭建了某型飞机典型设备舱振动测试系统, 基于OPAX方法搭建了机载设备的振动环境预计模型, 并对其预计准确度进行了验证。对比预计结果与试验结果, 得到: ①新工况下模型预计均方根值与试验测试均方根值相比, 误差保持在20%以内; ②在预计频段范围内, 新工况下模型预计的变化趋势与试验测试基本一致, 个别频率处差异较大。综合新工况下预计结果, 这种基于OPAX的振动环境预计方法预计精度较高, 且搭建模型所需数据量较少, 搭建方便, 具有可操作性和工程实用价值。

摘要

It is widely known that obtaining the vibration environment of the aircraft structure and airborne equipment accurately is very important. The traditional vibration environment prediction method always has low accuracy, which may lead to the problem of over-test or under-test in the later vibration test. In this study, an innovative vibration-environment-prediction method is put forward based on operational path analysis with exogenous inputs (OPAX) method. In the laboratory, the vibration testing system is built, which focuses on one typical equipment cabin. Adopting the testing data, a vibration environment prediction model is set up, and its accuracy is verified under new loading condition. Through comparative analysis of prediction and test results, the conclusions can be drawn that: ①the error of the RMS value of the prediction model is kept within 20% when compared with the RMS value of the real testing data; ②within the frequency band range, the change trend of the prediction result is basically consistent with that of the test result, only at some individual frequencies, there is a big difference. It can be concluded that the prediction model built in this paper, which has high accuracy and is convenient to build, has a relatively high engineering practical value.