13th International Conference on Fracture June 16–21, 2013, Beijing, China -2- failure in the splice opening between the aluminum splice edges filled with resin during production of the material and the delamination extension in the loading direction. Several researchers have developed theoretical concepts to describe the observed crack growth behaviour in fiber metal laminates [5-10]. These concepts start from the available methods for crack growth in monolithic aluminium sheets with additional parameters describing the bridging effect. In general, fatigue crack growth in a fiber metal laminate such as Glare is accompanied by delamination growth at the interface between the aluminium and glass fiber/adhesive layers. To incorporate this delamination growth in crack growth prediction methods, the energy release rate approach is applied to describe the delamination growth rate [7-10]. Few researchers have investigated the delamination behavior for different splicing geometries and layer thicknesses. Vries et al. [11] applied Griffith’s energy criterion to calculate a delamination resistance, and Hashagen et al. [12] described the delamination in the interface by a plasticity based material model derived from a Hoffman-like yield function which bounds all states of stress in the interface. However, it is noticed that Vries et al. [11] and Hashagen et al. [12] only paid attention to the second falure processes, i.e., delamination between the prepeg layer and the aluminum layer, and the failure criterion for the splice opening between the aluminum splice edges has not been established. On the other hand, only the mechanical loading is considered in above researches, so that the established theories are not suitable for the bonded structures subjected to coupled thermo-mechanical loading. In this paper, attempt is made to predict splice failures in fiber metal laminate subjected to coupled thermo-mechanical loading using stress singularity theory. In order to solve stress fields near the apex of bonded dissimilar materials as shown in Fig. 1, a super wedge tip element with numerical asymptotic solutions developed by Sze et al. [13] is firstly established and used for thermo-mechanical finite element analysis. Critical stress intensity factors are used as control parameters for fracture initiating at the bimaterial interface edge, and to predict fracture load for varying splice width and fiber layer thickness. The theoretical results are compared with experimental results for verification purposes. Fig. 1 Description of a bi-material wedge containing a super wedge tip element 2. Element stiffness matrix of the super wedge tip element As shown in Fig. 1, a domain composed of bi-material sectors can be partitioned into inner and outer regions. The accurate solution to the entire domain requires coupling of the numerical solution in the inner region with that of the approximate solution through the finite element in the outer region. The coupling can be achieved by developing a super wedge tip element (as shown in Fig. 1) whose interpolation functions satisfy the governing equations exactly near the apex enforcing the inter-element displacement continuity along the common boundary and the nodes between the super y 1 ˆΓ 2 ˆΓ ˆn o α1 α2 1ˆu 2ˆu x θ r
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