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A dynamic mode-I energy release rate (ERR) of a double cantilever beam (DCB) under impact from a striker is derived for the first time for isotropic and orthotropic composite materials, accounting for DCB properties, a striker mass and an initial impact velocity. This is achieved in the context of structural vibration analysis by employing beam dynamics. It is found that the initial impact velocity determines the magnitude of the ERR, which is proportional to the velocity squared, while the delamination length ratio and the mass ratio between the striker and the DCB defines the time response. To understand the transient effect, a dynamic factor is defined as a function of the mass ratio. This factor decreases with an increasing striker mass, indicating a transition in the dynamic response from flexural-wave dominant to quasi-static-motion dominant, allowing an attunable dynamic effect. The developed theory is verified against the finite-element simulations for isotropic and orthotropic materials as well as experimental verification using published data. This work allows the measurements of fracture toughness under the impact load with the derived analytical solution. In addition, the developed theory can guide a design of impact tests and provide a fundamental understanding of impact-induced fracture for carbon-fiber-reinforced plastics. [Display omitted] [ABSTRACT FROM AUTHOR]

The double cantilever beam (DCB) tests are widely used to assess the interfacial delamination properties of laminated composites. For quasi-static loads, the DCB tests are standardized based on the beam mechanics; for dynamic loads, however, such as high-loading-rate impact and cyclic loads, there is no established analytical theory. This presents a significant obstacle preventing the research community from assessing the delamination behavior of composites or adhesives for their application under complex in-service loads. In this paper, the theory of evaluating dynamic mode-I delamination driving force for DCBs under general displacement loads is developed for the first time, accounting for structural vibration effects. The developed theory is demonstrated by two examples: high-loading-rate split Hopkinson bar impact and cyclic fatigue loads. The analytical solutions are validated by published experiment results and in-house tests. This work provides a fundamental analytical tool to study and assess the fracture behavior of fiber reinforced-polymer composite and adhesive materials under various loading conditions. [Display omitted] • Analytical theory developed for mode-I dynamic energy release rate. • Quasi-static, dynamic, and general cyclic loads solved analytically. • Structural vibration included to account for dynamic effect. • Dynamic effect studied and quantified with induced displacement. • Finite-element-method simulation and in-house fatigue test verify the analytical theory. [ABSTRACT FROM AUTHOR]