A study of dynamic pull-through failure of composite bolted joints using the stacked-shell finite element approach

Abstract

Pull-through failure of bolted joints in composites is due to the relatively low through-thickness properties of laminated materials. Recently it has been identified that pull-through failure also plays an important role in the ultimate bearing load and total energy absorption of bolted joints, especially under dynamic conditions. AbstractPull-through failure of bolted joints in composites is due to the relatively low through-thickness properties of laminated materials.Recently it has been identified that pull-through failure also plays an important role in the ultimate bearing load and total energy absorption of bolted joints, especially under dynamic conditions. It has been previously found that bolted joints loaded in bearing exhibit rate sensitivity whereas bolts loaded in pull-through experience very little sensitivity, for nearly identical joint configurations. The primary focus of this paper was to use explicit finite element simulation of pull-through failure to shed light on discrepancies between experimentally observed rate sensitivity for seemingly similar tests. The paper uses the stacked-shell modelling approach to efficiently model the interaction of delamination and ply failure under the complex dynamic load state.The results of the simulation indicated that the properties of the interface susceptible to loading rate sensitivity, Mode I and II strain energy release rates (SERR), did not have a great effect on the overall joint response; despite the prevalence of delamination during the failure process. A weak relationship between Mode II SERR and joint response was discovered which was consistent with experimental observations.

Experimental Investigation of Fastener Pull-out Response in Composite Joints under Static and Dynamic Loading Rates

“…Further observations on the reported loaddisplacement curves indicate that there are two general forms of such plots, as shown in Fig. 2 and as also stated by Pearce et al [21]. These two forms are primarily affected by the specimen thickness and the ratio of the CHD to the fastener head diameter.…”

“…The majority of the previous works referred to quasi-static loading conditions; with only two authors investigating the impact response of composite bolted joints during pull-through loading [7,8]. Initially, Pearce et al [7] tested T300/Cycom970 plain weave square plates of 65 mm × 65 mm × 3.52 mm with a centrally located 100 o flush head bolt and a 55 mm CHD support at various impact velocities, ranging from quasi-static up to 5 m/s (some results with 10 m/s can also be found from this research group in [21]). In their tests, limited strain rate sensitivity was observed between the quasi-static and the impact velocity testing range.…”

Finite element analysis of catastrophic failure of dynamically-loaded countersunk composite fuselage joints

“…Although delamination was not modelled explicitly, the use of Puck criteria allowed for the prediction of ply failures which mimicked delaminations [21]. Furthermore, the Mohr-Coulomb type intralaminar failure criteria ensure that through-thickness compressive forces increase resistance to laminate splitting, which is physically realistic (and was found to be important in [13]). For further details on the damage model and the joint modelling approach, see [9].…”

Development of experimental and numerical methodologies for the investigation of composite and hybrid metal-composite fastened joints subjected to impact loads

“…It is noted that this load value (not the maximum one) should be used in the design, as it corresponds to the onset of delamination failures which may propagate under fatigue loading conditions. Further observations on the reported loaddisplacement curves indicate that there are two general forms of such plots, as shown in Figure 2-14 and as also stated by Pearce et al [176]. These two forms are primarily affected by the specimen thickness and the ratio of the CHD to the fastener head diameter.…”