This work is focused on the study of orthogonal cutting of long fiber composites. A model based in finite element was developed. The mechanisms of chip formation of Glass and Carbon Fiber Reinforced Polymer (FRP) composites were analyzed. Significant differences were observed when comparing machining induced damage predicted with the model for both materials. While damage extended widely ahead the interface and beneath the tool tip in the case of GFRP, damage was located in a much smaller zone in the case CFRP. The fiber orientation influences both the mechanism of chip formation and the induced subsurface damage.

a b s t r a c tA new set of failure criteria to predict composite failure in single lap bolted joints is proposed. The pres ent failure criteria are an extension of Chang Lessard criteria considering a three dimensional stress field and including out of plane failure modes. The advantage with respect to other three dimensional failure criteria is the consideration of non linear shear stress strain relationship. The failure criteria were imple mented in a finite element model and validated through comparison with experiments in literature. Stresses were calculated by a non linear finite element model developed in ABAQUS/Standard which con siders material and geometric nonlinearities. A progressive damage model was implemented in a USDFLD subroutine. The model predicted the effect of secondary bending and tightening torque showing an excel lent agreement with experimental results. Moreover, results were compared with those reported in lit erature using Hashin failure criteria. In addition, a parametric study was carried out to analyse the influence of friction coefficient and tightening torque.

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CFRPs Drilling Delamination ModelingDelamination is one of the undesired effects of machining using non appropriate cutting parameters or worn drill. Finite element modeling of drilling of Carbon Fiber Reinforced Polymer (CFRP) composites is an interesting tool for damage prediction. Recently, complete modeling of the process including the rotatory movement of the drill, penetration in the composite plate and element erosion has been developed in the scientific literature. Computational cost of these complex models is a great disadvantage when comparing them with simplified models that consider the drill acting like a punch that pierces the laminate. In this paper both complete and simplified models were developed and compared in terms of delamination prediction. The simplified model, presenting reduced computational cost, slightly overestimates the delamination factor when compared with the complex model. The influence on delamination of thrust force, clamping area at the bottom surface of the laminate and the stacking sequence is studied using the simplified model.

The first objective of this paper is to analyze the influence of mesh size and shape in finite element modeling of composite cutting. Also the influence of the level of energy needed to reach complete breakage of the element is considered. The statement of this level of energy is crucial to simulate the material behavior. On the other hand geometrical characteristics of the tool have significant influence on machining processes. The second objective of the present work is to advance in the knowledge concerning tool geometry and its effect in composite cutting.A two-dimensional finite element model of orthogonal cutting has been developed and validated for Glass LFRP composite, comparing with experimental results presented in scientific literature. It was demonstrated that both numerical parameters and tool geometry influence the predicted chip morphology and machining induced damage.