Behavior and Failure Modes of Sandwich T-Joint Using Cohesive Zone Material Model and Contact Elements
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Behavior and Failure Modes of Sandwich T-Joint Using Cohesive Zone Material Model and Contact Elements S. M. R. Khalili & A. Ghaznavi
Received: 29 December 2010 / Accepted: 18 January 2012 / Published online: 16 February 2012 # Springer Science+Business Media B.V. 2012
Abstract One of the significant concerns of sandwich panels is their joints. T-joint is one the most common joint in sandwich structures. This paper deals with the numerical study of triangle T-joint under static loading. The results of numerical solution obtained by ANSYS modeling are verified with the results of experimental tests obtained in the literature. In general, the results obtained for anticipated failure load by numerical solution with the results of experimental test is in good agreement. Contact elements and cohesive zone material model are used to model the adhesive layer, hence debonding and fracture of adhesive is observed by the numerical modeling. Also, by using a written macro code in the ANSYS software, the ability of damage is explained for the core of sandwich panels; thus both the modes in fracture of T-joints (core shear failure in base panel and debonding of adhesive) are modeled. Core materials consist of Divinycell H100, H160, H250, and HCP70 are used for modeling sandwich panels, so that the function of joint is studied under different conditions of the sandwich core material. Nine different geometrical models are created by changing the base angle of the core triangle. The absorbed energy associated with different segments of the T-joint are used to investigate the effect of joint geometry and core material on the load transfer and failure mode of the T-joint. Keywords Sandwich T-joint . Cohesive zone material model, Contact elements, Finite element analysis . Adhesive joint . Failure modes
1 Introduction Using sandwich panels in various industries including aerospace, ship construction, ground transportation, civil infrastructure and maritime is growing fast in last decades. Sandwich panels are mainly used, because of their advantages such as high bending strength, flexural rigidity, lightweight and high erosion resistance [1]. Among disadvantages of sandwich S. M. R. Khalili (*) : A. Ghaznavi Centre of Excellence for Research in Advanced Materials and Structures, K.N. Toosi University of Technology, Pardis St., Molasadra Ave., Vanak Sq, Tehran, Iran e-mail: [email protected]
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Appl Compos Mater (2013) 20:41–54
panels that decrease their performance in some structures are their joints [2]. Adhesively bonded joints have been extensively used in assembling sandwich structures made from glass fiber reinforced polymer skins and a PVC foam core. Advantage of this kind of the joints in comparison to mechanical joints like screw and rivet, is lack of local damages and high stress concentration factor in components of the joints [3]. One of the most common adhesive bonded joint is the T-joint. Figure 1 gives an illustration of a T-joint. It consists of a horizontal base panel, a vertical leg panel, fillers and tria
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