Analysis of crack interactions in laminates by means of the scaled boundary finite element method

• Applicant: Professor Dr.-Ing. Wilfried Becker
• Subject Area: Mechanics
• Term: from 2013 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 228806246

Goal of the intended project is the extension and application of the scaled boundary finite element method for the structural situation von interacting cracks in laminates made of unidirectionally fibre-reinforced single layers. Cracks in fibre-reinforced laminate layers typically occur as fibre-parallel matrix cracks, for instance from curing shrinkage, from thermal shrinkage or from external mechanical loading, for which the unidirectional fibre reinforcement has not much load carrying capability. In most cases such matrix cracks run directly in thickness direction of the laminate and this through a complete single layer, but sometimes also in a slant direction through the layer in order to be stopped at the interfaces to the neighbouring layers. If there is an analogous crack generation in a direct neighbouring layer then the respective matrix cracks can meet at the interface, and this due to the in general different crack orientations only at one single point with a corresponding crack interaction. Crack interaction can however also happen with delamination cracks within an interface. The crack interaction shall be investigated within the intended project within the framework of linear elasticity theory as a respective three-dimensional boundary value problem, which due to the involved anisotropic single layer continua is very challenging. Of particular interest are the occurring stress singularities in the interaction points of the involved cracks as well as the accompanying asymptotic stress and strain fields. In this situation an appropriate analysis approach is a scaled boundary finite element method that is correspondingly to formulate and to implement. The usefullness and efficiency of this new approach will be assessed by means of also intended finite element reference calculations.

• DFG Programme: Research Grants