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Damage thresholds for low velocity impact on aircraft structural composites

Published online by Cambridge University Press:  04 July 2016

B. A. A. O’Kane  and
P. P. Benham
B. A. A. O’Kane
Affiliation:
Short Bros PLC, Belfast
P. P. Benham
Affiliation:
Queen’s University, Belfast
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Summary

Seven composite laminates, three carbon, one Kevlar and three hybrid as supplied by an aircraft manufacturer were assessed for damage tolerance. Rectangular coupons were subjected to low velocity impact in the range 0-4 Joules by a swinging pendulum. The coupons were ultrasonically C-scanned to measure delamination area and visually inspected for damage. Residual strength tests in tension, compression, flexure and shear were then carried out on the damaged coupons. Visual damage, delamination damage and strength reduction thresholds were determined from the data and compared. Of the three thresholds, delamination damage and strength reduction tended to coincide. For the various lay-ups these were in the range of 1·5 to 2·0 J for the longer (tensile) specimens or in the case of the smaller (shear) specimens between 0·2-0·3 J. In all cases onset of visible damage occurred at slightly higher values of impact energy. The significance of specimen stiffness was noted.

Type
Research Article
Information
The Aeronautical Journal , Volume 90 , Issue 899 , November 1986 , pp. 368 - 372
Copyright
Copyright © Royal Aeronautical Society 1986 

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