Funding:

• • Federal Aviation Administration

Collaborators:

• • Prof. Hyonny Kim, UCSD

Synopsis:

This project is aimed at developing a tool for detecting and quantifying damage on composite aircraft structures caused by blunt impact. The problem in this case is that damage may occur in the underlying structure in a manner that is not visible from the outside. Of interest is damage detection in the skin, stringers, shear-ties and frames. A method based on ultrasonic guided waves is being developed for this purpose. In particular, a non-contact (air-coupled) ultrasonic scanning system has been designed. Different frequency ranges are being investigated, namely a low frequency range (<50 kHz) to penetrate into the shear-ties and C-frames, and a high frequency range (~100-200 kHz) to penetrate into skin and stringers. Statistic signal processing is being implemented to increase the SNR of the scans. These techniques are being validated on CFRP stiffened panels that are representative of commercial composite aircraft construction (e.g. Boeing 787) and have been subjected to impact tests at UCSD. Infrared Thermography is being used to provide an independent damage assessment. An additional objective of this work is to relate the damage detection to the residual strength/remaining life estimation. 

Selected Publications:

Capriotti, M. and Lanza di Scalea, F., “Robust non-destructive inspection of composite aerospace structures by extraction of ultrasonic guided-wave transfer function in single-input-dual-output scanning systems,” Journal of Intelligent Materials Systems and Structures, in press, 2019.

Cui, R. and Lanza di Scalea, F., “On the Identification of the Elastic Constants of Composites by Ultrasonic Guided Waves and Optimization Algorithm,” Composite Structures, 223, 2019.

Cui, R. and Lanza di Scalea, F., “Composite Property Identification from Inversion of Guided Wave Dispersion Curves and Simulated Annealing Optimization,” CD-ROM Proceedings of the 12th International Workshop on Structural Health Monitoring (IWSHM 2019), pp. 1-9, Stanford University, September 10-12, 2019.

Capriotti, M., Cui, R., and Lanza di Scalea, F., “Guided wave techniques for damage detection and property characterization in composite aerospace structures,” paper no. 10972-1, Proceedings SPIE Vol. 10972, Health Monitoring of Structural and Biological Systems XIII, part of SPIE Smart Structures and Nondestructive Evaluation Symposium, Denver, CO, 3-7 March, 2019.

Capriotti, M., Kim, H.E., Lanza di Scalea, F., and Kim, H., “Nondestructive Inspection of Impact Damage in Composite Aircraft Panels by Ultrasonic Guided Waves and Statistical Processing,” Materials Journal, Special Issue: Structural Health Monitoring for Aerospace Applications, V. Giurgiutiu and S Yuan, eds., 10(6), pp. 1-12, 2017. 

Capriotti, M., Kim, H.E., Lanza di Scalea, F., and Kim, H., “Detection of Major Impact Damage to Composite Aerospace Structures by Ultrasonic Guided Waves and Statistical Signal Processing,” Proceedings of the 10th International Conference on Structural Dynamics (EURODYN), Elsevier, Procedia Engineering, F. Vestroni, F. Romeo and V. Gattulli, eds., 199, pp. 1-6, 2017.