Impact Resistance Analysis of Toothed Periodic Metallic Damper Encased in Pipeline System

Transient impact loads pose significant challenges to the structural integrity of pipeline systems operating in extreme environments. To enhance impact isolation performance through structural regulation, a toothed periodic metallic damper (TPMD) inspired by fractal geometry is developed and employed as an encasing damping layer. The fractal-inspired toothed contour, combined with controllable radial density gradients, enables coordinated modulation of multi-scale contact evolution and transient load transmission within the porous metallic structure. The quasi-static compression behavior of TPMD is characterized experimentally and described using a Bergström–Boyce hysteresis constitutive model. Drop-impact experiments and finite element simulations are conducted to investigate the effects of pulse peak, pulse width, and density-gradient configuration on the dynamic response of the pipeline system. Results show that the TPMD-encased pipeline significantly reduces peak acceleration while extending pulse duration compared with a rigid pipeline configuration. A negative-gradient density distribution provides superior impact buffering capability by promoting progressive deformation and enhanced energy dissipation. The established numerical model demonstrates strong predictive capability, with deviations in peak acceleration and pulse width remaining within 6% of experimental results. The proposed fractal-gradient integrated design and validated modelling framework offer an effective strategy for impact-resistant design of pipeline systems subjected to short-duration dynamic loading.