基于声发射信号模式识别的 UHMWPE/ LDPE复合材料损伤机制分析

测定了 U HMWPE/ LDPE复合材料在准静态拉伸作用下的声发射 (AE) 信号 , 用无监督模式识别方法对预处理后的 AE信号进行分类 , 据此分析了几种试样 (0° 、90° 和 + 45° / - 45° ]) 的损伤机制。研究表明 ,模式识别 (PR) 方法能识别出试样中基体开裂、 纤维2基体界面脱粘、 纤维抽拔和纤维断裂等损伤模式 , 识别结果与利用扫描电子显微镜 (SEM) 对破坏断面观察得到的结果一致。U HMWPE/ LDPE复合材料的 AE信号特征只受损伤模式的影响而与试样类型无关 , PR方法能有效地区分不同损伤模式的 AE信号 , 每种损伤模式的 AE信号累计数对应变的关系曲线能清楚地反映复合材料的损伤进程。AE信号的 PR分析为复合材料的损伤机制分析提供了准确依据。 

Damage mechanisms analysis of UHMWPE/LDPE composites based on the use of pattern recognition techniques on acoustic emission signals

U HMWPE/ LDPE composites were tested to collect acoustic emission (AE) signals under a quasi2static tensile load. The unsupervised pat tern recognition ( PR) techniques were used to classify AE signals af ter their preprocessing. Damage mechanisms in several specimens (0° 、90°and + 45° / - 45° ]) were investigated according to the classifying result s. The study shows that the PR technique is able to identify damage modes in the specimens such as mat rix cracking , fiber2mat rix debonding , fiber pullout , fiber breakage , etc. The identification result s are the same with the observation result s of the f racture surfaces of the specimens observed by a scanning elect ron microscope (SEM) . For U HMWPE/ LDPE composites , the characteristics of the AE signal are not affected by the type of specimen but are dependent on the failure mode. The PR technique can classify the AE signals issued f rom different modes effectively. By the cumulative AE hit s of each damage mode vs st rain curves , the damage process of the specimens can be reviewed clearly. Using the PR technique on AE signals gives nicety evidence for the damage mechanisms analysis of composites.