The paper describes the results of a research activity, carried out at the Department of Aerospace Engineering at the University of Pisa, in conjunction with Agusta, aimed at the characterisation of the fatigue behaviour of composite joints. The activity was performed as a support to the certification of the tail of the new helicopter EH 101. Two types of specimens were defined taking the move from the design of the structure; they mainly differed in the thickness of the laminates, 2 and 4 mm, and were representative of critical areas. The specimens were impact damaged with an energy level capable of inducing a barely visible indentation, as required by the Certification Authority. Fatigue tests, under sinusoidal loading, R=0.2, were carried out both in dry and wet conditions; the stiffness of the specimens was monitored during the fatigue tests. The comparison between the results obtained shows the considerable effect of impact damage and of humidity absorption on the fatigue resistance of composite joints.
Fatigue behaviour of mechanically fastened joints in composite materials
LANCIOTTI, AGOSTINO;LAZZERI, LUIGI;
1995-01-01
Abstract
The paper describes the results of a research activity, carried out at the Department of Aerospace Engineering at the University of Pisa, in conjunction with Agusta, aimed at the characterisation of the fatigue behaviour of composite joints. The activity was performed as a support to the certification of the tail of the new helicopter EH 101. Two types of specimens were defined taking the move from the design of the structure; they mainly differed in the thickness of the laminates, 2 and 4 mm, and were representative of critical areas. The specimens were impact damaged with an energy level capable of inducing a barely visible indentation, as required by the Certification Authority. Fatigue tests, under sinusoidal loading, R=0.2, were carried out both in dry and wet conditions; the stiffness of the specimens was monitored during the fatigue tests. The comparison between the results obtained shows the considerable effect of impact damage and of humidity absorption on the fatigue resistance of composite joints.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
