PSI - Issue 14

Akhilesh Kumar Jha et al. / Procedia Structural Integrity 14 (2019) 416–428 Akhilesh Kumar Jha et al. / Structural Integrity Procedia 00 (2018) 000–000

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4. Simulation approach In CEL analysis of a bird impact, the Eulerian space through which the Eulerian material flows and collides with the Lagrangian structure is represented by a stationary cube. Meshing is simplified in the CEL approach, as there is no need to mesh the soft projectile (Bird). The Eulerian space is meshed with EC3D8R element, the only mesh type available in Abaqus for the Eulerian problems. The geometry of bird has been positioned along with composite plate fitted in the fixture inside the Eulerian domain, which completely engulfs both the composite plate with fixture and the bird. The Eulerian section assignment defines the materials that may be present in the mesh over the course of the analysis and an initial condition specifies which materials are present in each element at the beginning of the analysis. The initial condition effectively determines the initial topology of the materials in the models as shown in Fig. 3. A dynamic explicit step has been defined with a time period of 6 millisecond condition. Automatic time incrementation has been used without any mass scaling. General contact with frictionless tangential property has been defined for the interaction behavior. The impacting forces will be transmitted to the Lagrangian structure through Eulerian-Lagrangian contact, which is based on the penalty contact algorithm. The Eulerian implementation in Abaqus/Explicit is based on Volume-of-Fluid method. In this method, material is tracked as it flows through the mesh by computing its Eulerian volume fraction (EVF) within each element and has a value of zero and one. If a material completely fills an element, its volume fraction is one; if no material is present in an element, its volume fraction is zero. The volume fraction tool performs Boolean operation of reference geometry and the mesh. This creates a set of nodes that defines the initial position of bird in the Eulerian domain. 5. Simulation results The simulation was carried on two composite laminate plates consisting of different ply combinations. The geometric details of Plate-1 is shown in Fig. 4. The plate was impacted with 2lb (0.9 kg) bird travelling at velocity of 40m/s. In this paper, to study the structural response of different laminate plates, bird strike analysis on the plates has been carried out.

5.1. Test Plate-1

Fig. 4. Plate-1 Geometric details.

The Fig. 5 shows the bird strike event on the test plate-1 at different time interval. The stress generated due to impact are lower than the allowable stresses of the composite plate.