TY - JOUR
T1 - Thermo-mechanical fatigue analysis of liquid shim in mechanically fastened hybrid joints for aerospace applications
AU - Comer, A. J.
AU - Dhôte, J. X.
AU - Stanley, W. F.
AU - Young, T. M.
PY - 2012/6
Y1 - 2012/6
N2 - As resin-infused composite laminates continue to replace alloy components in modern commercial aircraft, liquid-shim is often necessary to compensate for assembly tolerances occurring in mechanically-fastened primary structures. This paper evaluates the structural performance of aerospace-grade liquid-shim in double-bolt composite-aluminium alloy 'hybrid' joints representative of multi-fastener joints found in the primary structures of modern commercial aircraft. Hybrid joints with liquid-shim were subjected to simultaneous thermal and mechanical-fatigue (TMF) loading conditions representative of those experienced over the lifetime of a commercial aircraft. The joints were subjected to 200,000 fatigue load cycles at -59. °C and 100,000 fatigue load cycles at +85. °C to simulate service conditions. Key variables investigated were shim material and shim thickness. The main conclusions from this study are: (i) there was no degradation of the liquid-shim in terms of a loss of mechanical stiffness and, secondly, no significant damage was observed on the bearing-plane; (ii) a reduction in joint stiffness due to the presence of liquid-shim was observed using high magnification 2D digital image correlation (DIC) and the reduction was dependent on the thickness of liquid-shim employed; and (iii) joints with second generation liquid-shim exhibited marginally lower stiffness relative to joints manufactured with third generation liquid shim.
AB - As resin-infused composite laminates continue to replace alloy components in modern commercial aircraft, liquid-shim is often necessary to compensate for assembly tolerances occurring in mechanically-fastened primary structures. This paper evaluates the structural performance of aerospace-grade liquid-shim in double-bolt composite-aluminium alloy 'hybrid' joints representative of multi-fastener joints found in the primary structures of modern commercial aircraft. Hybrid joints with liquid-shim were subjected to simultaneous thermal and mechanical-fatigue (TMF) loading conditions representative of those experienced over the lifetime of a commercial aircraft. The joints were subjected to 200,000 fatigue load cycles at -59. °C and 100,000 fatigue load cycles at +85. °C to simulate service conditions. Key variables investigated were shim material and shim thickness. The main conclusions from this study are: (i) there was no degradation of the liquid-shim in terms of a loss of mechanical stiffness and, secondly, no significant damage was observed on the bearing-plane; (ii) a reduction in joint stiffness due to the presence of liquid-shim was observed using high magnification 2D digital image correlation (DIC) and the reduction was dependent on the thickness of liquid-shim employed; and (iii) joints with second generation liquid-shim exhibited marginally lower stiffness relative to joints manufactured with third generation liquid shim.
KW - Composite hybrid joints
KW - Digital image correlation
KW - Liquid-shim
KW - Thermal-mechanical fatigue
UR - http://www.scopus.com/inward/record.url?scp=84859003892&partnerID=8YFLogxK
U2 - 10.1016/j.compstruct.2012.01.008
DO - 10.1016/j.compstruct.2012.01.008
M3 - Article
AN - SCOPUS:84859003892
SN - 0263-8223
VL - 94
SP - 2181
EP - 2187
JO - Composite Structures
JF - Composite Structures
IS - 7
ER -