Temperature-dependent monotonic and fatigue bending strengths of adhesively bonded aluminum honeycomb sandwich beams

The monotonic and fatigue strengths of adhesively bonded aluminum honeycomb sandwich beams subjected to four-point bending were investigated at temperatures ranging from −25 to 75 °C. Experimental results showed that the ultimate loads in the monotonic tests and fatigue strengths in the fatigue tests decrease as temperature increases, and the failure mode changes from local indentation to debonding at the skin/core interfaces. An analytical procedure based on the temperature-dependent monotonic strengths of face/core materials and simple adhesively bonded specimens were used and accurately predicted the ultimate applied loads in the monotonic tests by comparing the theoretical limit loads corresponding to several failure modes, i.e., face failure, local indentation, core shear failure, and face/core debonding modes. Furthermore, by modifying the monotonic analytical procedure and incorporating the temperature-dependent S–N curves of the face/core materials and the simple adhesively bonded specimens, the fatigue life of the sandwich beams could be predicted by comparing the estimated fatigue lives corresponding to various failure modes. Comparing the evaluated ultimate loads and fatigue lives with the observed data confirmed that the good prediction performance was obtained both in the monotonic and fatigue analyses.

► Monotonic/fatigue strengths of sandwich beams decrease with increasing temperature.
► Failure mode transfers from local indentation to debonding as temperature increases.
► Ultimate load was predicted by competing among solutions for various failure modes.
► Fatigue life was predicted by comparing assessed lives for various failure modes.
► Good prediction performances in ultimate loads and fatigue lives were obtained.