Panasiuk Katarzyna, Dudzik Krzysztof
Faculty of Engineering, Gdynia Maritime University, 81-225 Gdynia, Poland.
Materials (Basel). 2022 Jan 2;15(1):313. doi: 10.3390/ma15010313.
Composite materials are used in many industries. They are construction materials that are being used more and more often, which makes it necessary to accurately identify the process of their destruction. Recent decades have resulted in an intensive increase in diagnostic tests of structures and mechanical elements. Non-destructive testing (NDT) represents a group of test methods (surface and volumetric) that provide information about the properties of the tested element without changing its structure. The method of acoustic emission (AE) is also being used more frequently. Thanks to the ability to detect and locate signal sources, as well as to perform tests during operation, it is a method that is increasingly used in industry. In this article, the acoustic emission was used to analyze the changes occurring in composite materials. Obtained parameters helped to determine the signals originating from fibre delamination, fibre cracking, etc., as well as the starting point of these changes and the stress values at which these changes occurred. The analysis of acoustic emission signals recorded during the tests helped to determine the values of amplitudes characteristic for the destruction mechanisms of considered composite materials. Signals with an amplitude in the range of 30-41 dB may indicate elastic-plastic deformation of the matrix. Signals with an amplitude in the range of 42-50 dB indicate matrix cracks with the accompanying phenomenon of fibre delamination. Signals with amplitudes greater than 50 dB indicate fibre breakage. Based on the test results, the permissible stress was determined; when exceeded, the mechanisms of damage to the structure of composite materials accumulate. This stress limit for the tested material is 70 MPa. The use of the acoustic emission method in mechanical tests may contribute to a greater knowledge of composite materials used as a construction material, as well as determine the stresses allowable for a given structure.
复合材料被应用于许多行业。它们作为建筑材料正被越来越频繁地使用，这使得准确识别其破坏过程变得必要。近几十年来，结构和机械元件的诊断测试急剧增加。无损检测（NDT）是一组测试方法（表面和体积检测），可在不改变测试元件结构的情况下提供有关其性能的信息。声发射（AE）方法也越来越频繁地被使用。由于能够检测和定位信号源，以及在运行过程中进行测试，它是一种在工业中越来越常用的方法。在本文中，声发射被用于分析复合材料中发生的变化。获得的参数有助于确定源自纤维分层、纤维开裂等的信号，以及这些变化的起始点和发生这些变化时的应力值。对测试期间记录的声发射信号的分析有助于确定所考虑的复合材料破坏机制的特征振幅值。振幅在30 - 41 dB范围内的信号可能表明基体的弹塑性变形。振幅在42 - 50 dB范围内的信号表明基体裂纹并伴有纤维分层现象。振幅大于50 dB的信号表明纤维断裂。根据测试结果，确定了允许应力；当超过该应力时，复合材料结构的破坏机制开始累积。该测试材料的应力极限为70 MPa。在机械测试中使用声发射方法可能有助于更深入了解用作建筑材料的复合材料，并确定给定结构允许的应力。
