基于压电信号的复合材料疲劳寿命评估方法
Fatigue assessment for composites by using piezoelectric signal
肖玉善 1吴振 1任晓辉2
作者信息
- 1. 西北工业大学 航空学院,西安 710072
- 2. 西安航空学院 机械工程学院,西安 710077
- 折叠
摘要
复合材料结构应变特征随着疲劳加载发生变化,因此本文尝试实时监测疲劳周期内复合材料结构的应变特征信号,通过应变信号评估结构疲劳寿命.然而已有研究表明,电阻式应变片在长时间动态测试中经常出现提前疲劳失效,不适合疲劳全周期内应变信号采集.为此,具有高耐疲劳性的新型聚偏氟乙烯压电薄膜(Polyvinylidene difluoride piezoelectric film,PVDF)被用于采集复合材料结构疲劳特征信号.通过在碳纤维增强树脂基复合材料(T700/9A16)层合板表面粘贴PVDF薄膜,获取层合板疲劳过程中的压电信号.基于压电效应,将表征疲劳损伤状态的应变信息转化为PVDF压电信号输出.基于试验生成的压电信号数据库,采用随机森林回归算法高效地建立压电信号与复合材料层合板疲劳循环次数之间的关联.通过不同循环次数下的PVDF压电信号可以准确预测试验件的实际疲劳加载次数,实现了对复合材料结构疲劳状态的有效评估.
Abstract
Considering the strain characteristics of the composite structures changing with fatigue loading,so that this paper attempts to monitor the strain characteristics in real time during the fatigue cycle and assesses the fa-tigue life through the strain signals.However,from the published literatures,resistance strain gauge often suffered from early fatigue failure in the long-time dynamic testing,which is not suitable for strain signal acquisition during the full fatigue cycle.Therefore,the novel polyvinylidene difluoride piezoelectric film(PVDF)with high fatigue resistance is used to acquire fatigue characteristic signals of composite structures.The piezoelectric signals during the fatigue process of the composite laminates are obtained by pasting PVDF on the surface of carbon fiber rein-forced plastic(CFRP)plates(T700/9A16).Based on the piezoelectric effect,the strain information during the fatigue process is converted into the piezoelectric signal from PVDF.Then,a Random Forest Regression(RFR)algorithm is trained based on the database generated from the experimental tests to efficiently establish the correla-tion between the piezoelectric signals and fatigue cycles of composite laminates.Through the trained RFR network,the actual fatigue cycles of the test pieces can be accurately predicted based on the piezoelectric signals,in which the maximum percentage error of logarithms of fatigue cycles is controlled within 5％.This paper provides a new research idea and technical support for the fatigue life assessment of composite materials.
关键词
复合材料/剩余刚度/疲劳/PVDF压电薄膜/疲劳评估/随机森林回归Key words
composite plate/residual stiffness/fatigue/PVDF/fatigue assessment/Random Forest Regression引用本文复制引用
出版年
2024
NETL
NSTL
万方数据