On the rate dependent behaviour of epoxy adhesive joints: Experimental characterisation and modelling of mode I failure

Abstract

The increasing use of adhesive joints in dynamic applications require reliable measurements of the rate-dependent stress-displacement behaviour. The direct measurement of the stress-displacement curve is necessary when using cohesive models in discretised solutions of boundary value problems in solid mechanics. This paper aims to investigate the rate-dependent tensile failure of adhesive joints by using a new experimental methodology-it relies upon the combination of the stress wave propagation theory and digital image correlation methods on high speed footage to quantify the tensile stress and the dissipated energy respectively. For this purpose, the Split Hopkinson Bar methodology was employed-the experimental configuration was optimised using numerical modelling. To prove the sensitivity of our framework, two different adhesives are characterised at different loading rates: the adhesive failure strength was found to increase considerably with the strain rate, while the plastic deformation of these adhesives was reduced. The film adhesive showed superior performance over the particle toughened one. In the final part, a rate-dependent cohesive zone model is proposed, one which captures the measured behaviour and which has the potential to be used in industrial applications.

Experimental characterisation and numerical modelling of the influence of bondline thickness, loading rate, and deformation mode on the response of ductile adhesive interfaces

“…The high-rate (HR) experiments were performed on a Split Hopkinson Tensile Bar (SHTB) apparatus [44], particular details are provided in [45]. The specimens were loaded with a velocity of v = 3000 mm/s.…”

“…For MR and QS, the loading force was measured using the load cell from the testing frame while the rapid unloading process was measured using a strain gauge attached to the loading bar. The force was then synchronised with the displacement following the procedure previously described by the authors [45].…”

Rate-Dependent Cohesive Models for Dynamic Mode I Interfacial Propagation and Failure of Unidirectional Composite Laminates

“…There are many other researchers who developed rate-dependent cohesive law through direct fitting with experimental results, which were widely use in the simulation of adhesive interfaces [25][26][27][28]. May et al [11], Makhecha et al [25] and Yang et al [26] calibrated the rate-dependent parameters based on loading rates.…”

Experimental and numerical evaluations on the effects of adhesive fillet, overlap length and unbonded area in adhesive‐bonded joints

“…The outstanding mechanical properties of adhesive‐bonded joints, for example, lightweight, uniform stress distribution, watertight, excellent corrosion protection, 1 enhanced noise, vibration and harshness (NVH) performance, 2 and the ability to join different materials, 3,4 lead to increasing use in joining complex auto body structures 5 . From the durability design's perspective, 6 there is a specific need for analysis and design tools that can provide physical insight and characterize the effects of design variables.…”