Comparison of Cyclic and Monotonic Loading of a Double Cantilever Beam Adhesion Test

Abstract

Double Cantilever Beam (DCB) specimens were made from aluminium plates bonded with Hysol 1 EA9321 epoxy adhesive. These were tested both under monotonic and cyclic loading conditions. Experimental testing data were obtained from classic force and displacement measurements, as well as from backface strain recordings. Apart from the usual crack propagation monitoring, evolution of the process zone at the crack tip was studied during the experiment. Results of fatigue were compared with those of standard loading. Despite the viscoelastic nature of the adhesive, an elastic treatment of the results proved most satisfactory. In addition, good agreement was found between experimental and theoretical results obtained with a Timoshenko beam on Winkler elastic foundation model.

Testing mechanical performance of adhesively bonded composite joints in engineering applications: an overview

“…Many studies were performed for mode I and detailed procedures were developed. [132][133][134][135][136] A similar DCB framework is used for fatigue studies; however, a choice of loading conditions and, thus, definition of the loading ratio can be cumbersome due to the prismatic beam geometries [137][138][139] and hence the lap joint geometries are often preferred. [140][141][142] An important approach aiming in relieving G I from crack length dependence is Tapered DCB (TDCB) [143,144] schematically shown in Figure 4b.…”

Measurement of interface cohesive stresses and strains evolutions with combined mixed mode crack propagation test and Backface Strain Monitoring measurements

“…The so called Backface Strain Monitoring (BSM) technique have been applied on specimen designed for strength measurement such as lap shear specimens (Goglio and Rossetto, 2011;Khoramishad et al, 2010) or scarf joints (Gacoin et al, 2009), or on specimens designed for toughness measurement such as DCB specimens (Sanderson et al, 2012; or End Notched Flexure (ENF) ones Budzik et al, 2013a. BSM has enable to evidence cohesive stress distribution along the bondline in case of fatigue loading (Khoramishad et al, 2010;Budzik et al, 2013b) or stationary loading (Budzik et al, 2011) which could not be achieve with the J(h) technique. The analysis have been applied to mode I, mode II or mixed mode loading conditions.…”