Carbon Fiber Reinforced Composites Based On Lamb Waves Localization And Damage Identification Research

As composite materials are being used more extensively in engineering applications,there are increasing issues with damage and failure in composite structures.Therefore,it is crucial to conduct damage detection and maintenance for composite materials.Acoustic emission(AE)technology has been widely applied in damage monitoring in various fields,but traditional AE signal analysis methods have many limitations.Therefore,to conduct high-precision localization and damage identification research on carbon fiber-reinforced composite materials,based on Lamb wave theory,this study establishes a method for plane localization and damage classification recognition from a multi-modal perspective of acoustic source signal waveform to achieve effective evaluation of composite material structure health monitoring.Firstly,based on Lamb wave theory,this paper first established the calculation methods for arrival time and mode sound velocity of different modes.Using a pencil lead break(PLB)as an artificial sound source on a carbon fiber composite plate,a single sensor was used for linear localization and the results were analyzed.The results showed that using Lamb wave propagation characteristics for localization research on anisotropic materials is reasonable and accurate.Secondly,based on the established methods for mode arrival time and mode sound velocity,a fixed array composed of three sensors was designed to calculate the angle and distance of the sound source,and a planar localization calculation method was established based on this.To determine the effectiveness of the localization method,a carbon fiber composite plate PLB experiment was conducted,and the error sources of the localization results were analyzed.It was found that the accuracy of angle calculation has a significant impact on the localization results.In addition,the amplitude of different modes was determined by mode separation method,and PLB experiments were conducted at different angles.It was found that the amplitude of different modes decreases with increasing propagation distance,indicating that the localization method has a certain distance limitation.Finally,by implementing three single damage tensile tests,the main modal and frequency characteristics of the three damage signals were analyzed.According to these characteristics,a damage identification method based on MAR value was constructed,and the accuracy of the identification method was verified.The results showed that the accuracy rates of damage identification and classification were 91%,93.3% and 91.8% for single damage categories(matrix cracking,fiber fracture and stratified damage),respectively.The damage evolution process of carbon fiber composite plate tensile tests was analyzed using the damage identification and planar localization methods.The analysis results showed that the classified identification results of the signal events in the early stages of damage occurrence were consistent with the macroscopic damage level of the material,confirming the accuracy of the damage identification method.For the damage planar localization results,based on the damage signal frequency and mode features,the arrival time was recalculated,which effectively improved the accuracy of the damage localization results.