The Flexible Initiation Test (FIT): A new experimental test to characterize fracture initiation in mode I at the free edge of bonded assemblies

Comparison of three different adhesive joints using static and dynamic impact tests : Development of a new drop weight impact test rig incorporating a modified Arcan fixture

“…The steel impactor (noted (10) in Fig. 3) is maintained through two electromagnets (9). When experimental test begins, the impactor slides along the bar until to its stop position against the impact zone (2).…”

“…Three different adhesives are tested. We have already studied these adhesives to characterize their failure initiation in mode I using the Flexible Initiation Test [9]:…”

“…Within framework of work carried out on direct bonding process for optical space systems design [7,8,9], we need to characterize three adhesives via both static and dynamic tests in order to compare the identified properties and to find the best candidate. The chosen adhesive will be finally to integrate direct bonded optical space systems that are subjected to high dynamic loading in the launcher and static loading during preparation on the ground.…”

A cohesive zone model for fracture initiation and propagation of fused silica direct bonding interface

“…In previous investigations on direct bonding interface, we proposed the Flexible Initiation Test (FIT) to reduce the scattering of critical fracture initiation load measurements [27]. The FIT test uses deformable support beams bonded to sample (the sample includes the substrate and the adhesive).…”

“…In this paper, we develop a phenomenological cohesive zone model whose the parameters are identified on experimental results to model the fracture propagation and fracture initiation of elementary direct bonded assemblies. The first section presents three mechanical tests performed to characterize fracture propagation and initiation on a free edge: the wedge test [26], the flexible initiation test [27] and the cleavage test. For all samples tested, the confidential industrial bonding process is considered.…”