Simulation of Fatigue Delamination Growth in Composites with Different Mode Mixtures

Abstract

A numerical model, obtained by implementing a cyclic damage model in the framework of an interface element, is here proposed to reproduce the crack growth in laminated composites subjected to cyclically repeated loads. This model, which differs from the few studies in the literature on the topic, applies not only to single fracture modes but also to mixed modes, and to constant or variable crack growth rates. The applied load (in terms of force or displacement) is assumed to oscillate between a minimum and a maximum constant value. The Paris curve can be reproduced with accuracy once some parameters in the numerical model are tuned with experiments. These parameters are preliminarily found by simulating fatigue delamination in mode I (DCB test), in mode II (ELS or ENF test) and with a fixed mode mixture φ = GII/G (MMB test). A non-monotonic curve is then used to interpolate these preliminary results. Furthermore, tests where the mode mixture changes with crack length could also be reproduced. With this model it is possible to predict the crack growth rate with cycle of a generic structure without knowing a priori how the mode mixture φ changes during the crack propagation. This novel procedure gives a new opportunity in the design of composite structures subjected to repeatedly applied loads.

Methods for the prediction of fatigue delamination growth in composites and adhesive bonds – A critical review

“…Tumino and Cappello [184] modified this model by relating the model parameters C and β with the mode-mix in a manner similar to the way Blanco et al [97] related the Paris parameters C and n to the mode-mix. Robinson et al [180], Muñoz et al [183], and Tumino and Cappello [184] all present comparisons between predictions produced with (derivatives of) the model proposed in reference [180] and experimental data. In each case the same dataset is used [107] and good agreement is shown.…”

Predicting fatigue damage in adhesively bonded joints using a cohesive zone model

“…[21]. The cohesive zone model has been employed for predicting fatigue response of structures by several authors [22][23][24][25][26][27][28][29][30]. They coupled CZM with a fatigue damage evolution law to simulate fatigue degradation.…”

“…Therefore, others [22,30] tried to reduce the computational effort by employment of cyclic extrapolation techniques. Alternatively, some other researchers [23,24] developed fatigue damage models based on maximum fatigue load conditions. Robinson et al [23] incorporated a cumulative damage model based on the maximum fatigue load into the static CZM.…”

“…In this model, the fatigue model parameters need to be determined for every mode ratio. Later, Tumino et al [24] resolved this deficiency by considering the fatigue damage parameters as functions of the mode ratio. However, this resulted in introducing quite a few new parameters in the fatigue model and required an involved calibration process.…”

High Cycle Fatigue Damage Model for Delamination Crack Growth in CF/Epoxy Composite Laminates

“…An overview of delamination modeling for static loading can be found in (Tay Te, 2003). Few articles focus on delamination modeling in composite materials under fatigue loadings (Robinson et al, 2005;Tumino and Cappello, 2007;Turon et al, 2007).…”