Lagrange-based Modeling and Testing of Composite Structure Impact Dynamics

摘要

The use of composite materials for aerospace applications is driven by particular mechanical and thermal requirements. Several of these requirements are related to the structural integrity of primary structures undergoing dynamic loading. Thereby, impact of foreign objects is one of the most challenging factors in composite design because it causes very high unsteady loads in the multi-layer compound. Performance and safety especially for the residual compression stiffness contribute to a big extend to the exact knowledge of these loads together with the failure propagation mechanisms. Composite materials offer new aspects in design-to-application as they provide adjustable stiffness and thermal expansion in a wide range of mechanical and thermal loads. In order to analyze the impact behavior of composite structures a mobile impact test bed has been designed at Augsburg University of Applied Sciences. This test bed features an impact speed up to 25 [m/s] and a low-speed impact device for quasi-static analysis. The target of this paper is to highlight an innovative scheme that allows the assessment of impact on composite structures. Experimental testing and numerical simulation using a three-dimensional time accurate particle-cluster method that has been successfully validated against experimental findings from test cases defined for the analysis of liquid sloshing do the analysis. Here, the liquid dynamics simulation tool has been extended and coupled with a structural model of the composite. A comparison of the structural loads due to the impact interaction will be provided for a rigid composite and for a flexible composite. An outlook is provided showing the potential of this method for the determination of the energy dissipation rate during impact on composites.