Characterization and Scaling of Low Velocity Impact Response of Structures With Local Plastic Deformation: Implications for Design

Abstract

This paper presents a methodology for the characterization and scaling of response of structures having different shapes, sizes, and boundary conditions that are under impact by blunt objects through a characterization diagram. The diagram is constructed from an analytical functional relationship of the normalized maximum impact force and three non-dimensional parameters, namely the ‘Relative Stiffness’, ‘Relative Mobility,’ and ‘Effective Mass Ratio’. The efficacy of this diagram, which is developed using simple structural models, is demonstrated by FE simulations of more complicated and realistic structures and boundary conditions (clamped, stiffened plates and cylindrical panels). All the necessary parameters needed for characterization are determined using FE models simulating real-world experiments. The characterization method is validated for a wide range of impact parameters that cover the entire dynamic spectrum. It is expected that by determining the model parameters for various engineering structural elements and support conditions, the impact response and subsequent damage may be predicted in an early stage using the characterization diagram. The diagram can also be used to assess the accuracy of simple lumped parameter models and to provide clear guidelines for the choice of an adequate model for a given impact situation. As a result, the characterization diagram and simple models can be used for both the evaluation of finite element and other solutions, and as guides in the design of experiments and in scaling experimental results. The characterization diagram can be used as a powerful analytical prediction tool in various stages of design of complex structures subject to impact such as, initial design, testing and commissioning.