Influence of Nanoalumina Particles on the Static and High-Cycle Fatigue Properties of Peel-Loaded Adhesive-Bonded Joints

Abstract

Results of research are aimed at determining the possibility of improving the static and fatigue properties of peel-loaded adhesive-bonded joints of S235JR steel with an alumina nanopowder dispersed in an epoxy adhesive. The static properties were assessed in a T-peel test. The high-cycle fatigue strength tests were carried out on an electromagnetic inductor with the resonance frequency of the joint specimen. High-cycle fatigue was analyzed at the limited number of cycles 2 10 6 × . The tests were conducted on the specimens bonded with an Epidian 57 epoxy adhesive and a PAC hardener, whose properties were modified through the introduction of an alumina nanopowder. Four versions of the filled epoxy adhesive were examined, 0.5, 1.5, 2, and 3 wt.% of the dried nanopowder were dispersed in the epoxy adhesive. Fatigue strength tests revealed a significant improvement of the fatigue lifetime of adhesive-bonded joints due to the addition of fillers. In the best case a more than five-fold increase in the fatigue lifetime was obtained (from 199,500 to 1000,000 cycles). The fatigue strength for the best case increased by about 19%.

Investigating and Analyzing the Stress Distribution in Flexible Adherend for Peel-Loaded Adhesive Joints

“…This study's primary focus is to accurately determine the stress distribution within the adhesive layer, which is achieved solely by measuring the deflection amplitude of the free end of the flexible adherend. Typically, in fatigue tests, this amplitude measures around 1 mm [16], [17]. Therefore, we conducted our measurements within the range of 0 to 1 mm displacement of the free end of the flexible adherend.…”

A modified dissipated energy fatigue criterion to consider the thermo-oxidative ageing of electrically conductive silicone adhesive joints

“…Such an evolution of the joint stiffness, and especially the distinction between stage 2 and 3, can be related to the evolution of the natural frequencies of a bonded assembly illustrated in (45): the drop of the resonant frequency noticed by the authors of (45) can indeed be explained by the decrease of the joint stiffness.…”