Stijn Debruyne

Variability analysis on the structural elastic properties of adhesively joined cylinders

Elastic structural adhesives have very attractive mechanical properties compared to brittle ones, especially in dynamically loaded structures and applications. They often combine an acceptable stiffness and bonding strength with excellent impact and vibration damping properties. Their viscoelastic nature involves some complexities however. For these adhesive types the apparent stiffness changes with time, temperature, frequency and amplitude of the applied mechanical load. Moreover, each bonding process involves variability that reflects on the (dynamic) mechanical behaviour of completed adhesively joined structures. This paper discusses part of an extensive research project on the uncertainty assessment of adhesive joint lifetime in case of fatigue loads. A first part of this paper deals with uniaxial quasi-static cyclic tests on nominally identical adhesively bonded samples, with a simple cylindrical geometry. The second part discusses dynamic measurements of a similar sample and identical load case, and identifies the effect of different load amplitudes. It also links the quasi-static measurements to the results of the dynamic measurements. Finally the paper concludes the research results and highlights the ongoing and planned activities.

Using Experimentally Determined Resonant Behaviour to Estimate the Design Parameter Variability of Thermoplastic Honeycomb Sandwich Structures

Honeycomb panels combine a high specific strength and stiffness with a low areal mass. Consequently, these structures are ideally suited for ground transportation vehicle purposes. They have a complex but regular geometry.