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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Fig. 2. Bird geometry.

As birds, mostly composed of water, a water-like hydrodynamic response has been considered as a valid approximation for a constitutive model for bird strike analyses. The Equation of state (EOS) describes the pressure volume relationship with parameters of water at room temperature, hence the Mie-Grüneisen EOS Us-Up approach in Abaqus/Explicit was adopted for this purpose. The material properties used for bird is as shown in Table 1.

Table 1. Material Properties of bird. Properties

Values

ρ (kg/m 3 )

960

Γo

0

1480

C o (m/s)

0

S

3.2. Composite plate modeling The plate studied was laminate of woven fabric made of carbon fibers reinforcing epoxy matrix. The plate was produced with 0 o /90 o and 45 o ply using wet layup process with a fiber volume fraction of 45%. Both sandwich and monolithic plates has been used in the study. The sandwich plate consists of face plates of woven carbon fabric and low-density foam core. The dimension of plate was 400*400mm, with a woven glass fabric on the outer side. Woven fabric offer a good combination of damage tolerance, specific stiffness, and specific strength, when compared to unidirectional laminates with an equivalent volume fraction of in-plane fibers in all orientations, they also, present a lower in-plane stiffness and strength due to the tow waviness. Also, woven composites are less vulnerable to delamination and typically display a superior impact response. Additionally, due to their textile nature, they offer a higher drapability during manufacturing. For these reasons, the application of woven composites in the aeronautical, naval, and automotive industry is becoming increasingly widespread, especially in crash relevant parts. The sandwich laminates were modeled in Abaqus as continuum shell face sheets of FRP Woven fabric and a soft foam core, by providing elastic and plastic behavior, material damage initiation, damage evolution and failure. Tie constraints has been used between face sheets and core. Rohacell 51WF foam core has been used in the manufacture of sandwich laminate plates. Crushable Foam model available in Abaqus was used with following parameters as shown in Table 2. Experimental results from uniaxial compression test were used for Crushable Foam Hardening value. Hydrostatic yield stress of Rohacell 51WF foam parameter was taken from literature. NLGEOM option was checked to capture large deformations. The core model was modeled as isotropic and meshed using C3D8R elements.