Gholizadeh Ali, Mansouri Hasan, Nikbakht Ali, Saghafi Hamed, Fotouhi Mohamad
Department of Mechanical Engineering, Amirkabir University of Technology, Tehran 1591634311, Iran.
Aerospace Engineering Department, K. N. Toosi University of Technology, Tehran 1591634311, Iran.
Polymers (Basel). 2021 Oct 26;13(21):3680. doi: 10.3390/polym13213680.
Interleaving composite laminates by nanofibers is a well-known method of increasing interlaminar fracture toughness. Among many possibilities, polycaprolactone (PCL) nanofibers is one of the best choices for toughening composite laminates. The influence of PCL on delamination mode of failure is considered before. However, the effect of PCL on other damage modes, such as fiber breakage and matrix cracking, is yet to be studied. In this study, the acoustic emission (AE) technique is applied to determine the effect of toughening composite laminates by PCL nanofibers on matrix cracking, fiber/matrix debonding, and fiber breakage failure mechanisms. For this purpose, mode I and mode II fracture tests are conducted on modified and non-modified glass/epoxy laminates. Three different methods, i.e., peak frequency, wavelet transform, and sentry function, are utilized for analyzing the recorded AE data from mode I test. The results show that applying PCL nanofibers not only increases the mode I critical strain energy release rate by about 38%, but also decreases different failure mechanisms by between 75 and 94%.
通过纳米纤维交错复合层压板是一种提高层间断裂韧性的著名方法。在众多可能性中，聚己内酯（PCL）纳米纤维是增韧复合层压板的最佳选择之一。之前已经考虑过PCL对分层破坏模式的影响。然而，PCL对其他损伤模式，如纤维断裂和基体开裂的影响还有待研究。在本研究中，应用声发射（AE）技术来确定PCL纳米纤维增韧复合层压板对基体开裂、纤维/基体脱粘和纤维断裂失效机制的影响。为此，对改性和未改性的玻璃/环氧层压板进行了I型和II型断裂试验。利用三种不同的方法，即峰值频率、小波变换和哨兵函数，对I型试验记录的AE数据进行分析。结果表明，应用PCL纳米纤维不仅使I型临界应变能释放率提高了约38%，而且使不同的失效机制降低了75%至94%。
