Gałęzia Adam, Orłowska-Gałęzia Anita
The Faculty of Automotive and Construction Machinery Engineering, Warsaw University of Technology, Narbutta 84, 02-524 Warsaw, Poland.
Department of Intelligent Technologies, Institute of Fundamental Technological Research, Polish Academy of Sciences, Pawińskiego 5B, 02-106 Warsaw, Poland.
Materials (Basel). 2021 Mar 1;14(5):1154. doi: 10.3390/ma14051154.
Composite materials are widely used in many engineering applications and fields of technology. One of the main defects, which occur in fiber-reinforced composite materials, is delamination. It manifests itself in the separation of layers of material and the damaged structure once subjected to mechanical loads degrades further. Delamination results in lower stiffness and the decrease of structure's carry load capability. Its early detection is one of the tasks of non-invasive structural health monitoring of layered composite materials. This publication discusses a new method for delamination detection in fiber-reinforced composite materials. The approach is based on analysis of energy signal, calculated with Teager-Kaiser energy operator, and comparison of change of the weighted instantaneous frequency for measurement points located in- and outside of delamination area. First, applicability of the developed method was tested using simple models of vibration signals, reflecting considered phenomena. Next, the authors' weighted instantaneous frequency was applied for detection of deamination using signals obtained from FEM simulated response of the cantilever beam. Finally, the methods effectiveness were tested involving real experimental signals collected by the laser Doppler vibrometer (LVD) sensor measuring vibrations of the delaminated glass-epoxy specimens.
复合材料广泛应用于许多工程应用和技术领域。纤维增强复合材料中出现的主要缺陷之一是分层。它表现为材料层的分离，一旦受到机械载荷，受损结构会进一步退化。分层会导致刚度降低和结构承载能力下降。其早期检测是层状复合材料非侵入式结构健康监测的任务之一。本出版物讨论了一种用于检测纤维增强复合材料中分层的新方法。该方法基于用Teager-Kaiser能量算子计算的能量信号分析，以及对分层区域内外测量点加权瞬时频率变化的比较。首先，使用反映所考虑现象的简单振动信号模型测试了所开发方法的适用性。接下来，作者的加权瞬时频率被应用于使用从悬臂梁的有限元模拟响应获得的信号来检测脱层。最后，通过激光多普勒振动计（LVD）传感器测量分层玻璃环氧试样的振动所收集的真实实验信号，测试了该方法的有效性。
