A simplified modal-based method to quantify delamination in carbon fibre-reinforced plastic beam

Figures & data

Figure 1. Example of CFRP delamination [1].

Figure 2. Aluminium sheet (3 cm $\times$ 3 cm) fitted within the carbon fibre layer.

Figure 3. Effect of the sensor’s extra mass on the natural frequency reading.

Figure 4. Non-negligible mass installed on top of fixed-fixed bar.

Figure 5. Effect of the added mass on the three modal frequencies of a fixed-fixed bar.

Figure 6. Modal analysis: experimental apparatus.

Figure 7. Modal frequencies for delamination located at 50 mm, 71 mm and 105 mm.

Figure 8. Sensor position versus the three modal frequencies.

Figure 9. Location of sensors relative to the supports and the axis of symmetry.

Table 1. Sensor location and frequency shift for the second mode.

	Second Mode (Hz)
Location of sensor from the support (mm)	Position A	Position A’
30	300	302
50	276	288
70	258	274
90	256	264
110	266	266
130	282	276
150	298	298

Table 2. Sensor location and frequency shift for the third mode.

	Third Mode (Hz)
Location of sensor from the support (mm)	Position A	Position A’
30	492	496
50	484	526
70	482	524
90	544	556
110	580	580
130	578	570

Figure 10. Frequency shift for the second modal frequency.

Figure 11. Frequency shift for the third modal frequency.

Figure 12. Schematic representation of the restricted motion-based method.

Figure 13. Placement of the accelerometer.

Figure 14. Variation in the first modal frequency according to the restricted motion method.

Figure 15. Variation in the second modal frequency according to the restricted motion method.

Modeling Cracks and Delaminations in Carbon Fiber Composites, Center for Nondestructive Evaluation. Iowa state University. Carbon fiber composite laminates. Available from 2018 Dec 24: https://www.cnde.iastate.edu/research/ultrasonic/ultrasonic-and-composites/modeling-cracks-and-delaminations-in-carbon-fiber-composites/

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