| Sign In to gain access to subscriptions and/or personal tools. |
Application of the Finite-Element Method to Predict the Onset of Delamination GrowthDepartment of Mechanical Engineering, Institute of Technology of Aragón María de Luna 8, 50015 Zaragoza, Spain, majimenez{at}ita.es
Group of Composite Materials, Department of Mechanical Engineering, University of Zaragoza, María de Luna 3, 50015 Zaragoza, Spain This paper deals with a basic methodology for the application of the finite element (FE) simulation and linear elastic fracture mechanics (LEFM) to predict the onset of delamination growth. The first step of the proposed methodology is the experimental characterisation of material interlaminar fracture in pure mode I (DCB test), pure mode II (ENF test) and mixed mode I+II (MMB test). In the second step, the results of the interlaminar fracture tests are translated from load/displacement data to strain energy release rates by means of test FE simulations; thus, the critical strain energy release rate (Gc), or fracture toughness are obtained as a function of mode ratio. The third step of the methodology consists of applying FE simulations to determine the strain energy release rate (G) and mode ratio for the delamination and then comparing the result to the values of the Gc curve. The main innovative aspect of the paper is that FE simulation is used as a part of the material characterisation process; in fact, data reduction of interlaminar fracture tests is carried out by means of FE simulations. In addition, regarding the practical details of FE application to the proposed methodology, some innovative aspects are introduced, such as the analysis is carried out as a non-linear geometric problem (taken into account large displacements) and considering inside each simulation different elastic properties for the material depending on whether it is under tension or compression. These aspects and the rest of the proposed methodology are validated by the experimental results presented in the paper.
Key Words: strain energy release rate delamination interlaminar fracture mixed mode bending
Journal of Composite Materials, Vol. 38, No. 15,
1309-1335 (2004) |
|||