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8.21.14 Hu

PERIDYNAMICS SIMULATION OF DELAMINATION PROPAGATION IN FIBER-REINFORCED COMPOSITE MATERIAL

Yile Hu, NIA Visitor and Dept. of Aerospace and Mechanical Engineering, University of Arizona
August 21, 2014, 10:00 am, NIA, Rm 137
Host: Nelson Carvalho (NASA Langley)

Abstract:
Various numerical methods, especially the Finite Element (FE) method, have been developed and used to analyze the progressive damage and failure in advanced composite materials. The finite element method is typically used to solve the differential equations resulting from the equilibrium conditions of an infinitesimal material volume. However, the spatial derivatives needed to solve these equations, are not defined at the crack surface, or tip. Recently, a new continuum mechanics theory, Peridynamic theory (PD), has been proposed and applied to analyze crack initiation and propagation problems. Instead of using differential equations, PD method uses an integral formulation to establish the equilibrium equations. This avoids the computation of derivatives of displacement, and therefore the equilibrium equations are generally applicable, even in the presence of cracks.

In first part of this talk, the numerical implementation of PD will be discussed. Both an explicit and an implicit solver have been implemented using high-performance GPU parallel computing technology. By using an implicit algorithm, computational expense can be significantly reduced. Both approaches show good agreement. A mixed implicit-explicit solver was also developed and will be discussed.

In the second part of the talk, the application of Bond-based PD method to model progressive fiber, matrix and delamination damages in composite laminates will be discussed. Bonds with different properties are used to model fiber, matrix and interlayer materials. A new energy-based approach for evaluating the critical stretch of interlayer bonds is proposed based on fracture criteria suggested by Benzeggah and Kenane (BK). The new approach allows interlayer bonds to have varying critical stretches according to their deformation status. Two numerical verifications of delamination propagation, using the Double Cantilever Beam (DCB, Mode I) and Transverse Crack Tension (TCT, Mode II) tests, have been performed applying this approach. Results show good agreement with both numerical and experimental results available in the literature.

Bio:
Mr. Yile Hu is a visiting researcher at NIA. He is currently pursuing his PhD at the University of Arizona, major in Mechanical Engineering, focusing on applications of Peridynamics on composite materials with GPU computing. He obtained his M.S. Degree in Flight Vehicle Design from Shanghai Jiaotong University, China and his B.S. Degree in Aircraft Manufacture Engineering, Tongji University, China.

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