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

作　　者：肖玉善 吴振 任晓辉 XIAO Yushan;WU Zhen;REN Xiaohui(School of Aeronautics,Northwestern Polytechnical University,Xi'an 710072,China;School of Mechanical Engineering,Xi'an Aeronautical University,Xi'an 710077,China)

机构地区：[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

出　　处：《复合材料学报》2024年第9期4897-4908,共12页Acta Materiae Compositae Sinica

基　　金：国家自然科学基金(12172295)。

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。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 fatigue 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 reinforced 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 correlation 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 

分 类 号：TB333[一般工业技术—材料科学与工程]