Detecting of Barely Visible Impact Damage on Carbon Fiber Reinforced Polymer Using Diffusion Ultrasonic Improved by Time-Frequency Domain Disturbance Sensitive Zone
Detecting of Barely Visible Impact Damage on Carbon Fiber Reinforced Polymer Using Diffusion Ultrasonic Improved by Time-Frequency Domain Disturbance Sensitive Zone
Blog Article
Based on the decorrelation calculation of diffusion ultrasound in time-frequency domain, this paper discusses the repeatability and potential significance of Disturbance Sensitive Zone (DSZ) in time-frequency domain.The experimental study of Barely Visible Impact Damage (BVID) on Carbon Fiber Reinforced Polymer (CFRP) is carried out.The decorrelation coefficients of time, frequency, and time-frequency domains and DSZ are calculated and compared.
It has been observed that the sensitivity of the scattered wave disturbance caused by impact damage is non-uniformly distributed in both the General Wound Care - Retainer Dressings time and frequency domains.This is evident from the non-uniform distribution of the decorrelation coefficient in time-domain and frequency-domain decorrelation calculations.Further, the decorrelation calculation in the time-frequency domain can show the distribution of the sensitivity of the scattered wave disturbance in the time domain and frequency domain.
The decorrelation coefficients in time, frequency, and time-frequency domains increase monotonically with the number of impacts.In addition, in the time-frequency domain decorrelation calculation results, stable and repetitive DSZ are observed, L-THEANINE which means that the specific frequency component of the scattered wave is extremely sensitive to the damage evolution of the impact region at a specific time.Finally, the DSZ obtained from the first 15 impacts is used to improve the decorrelation calculation in the 16-th to 20-th impact.
The results show that the increment rate of the improved decorrelation coefficient is 10.22%.This study reveals that the diffusion ultrasonic decorrelation calculation improved by DSZ makes it feasible to evaluate early-stage damage caused by BVID.