Spectral Interaction in In-Transit Additive Manufacturing: A Comparative Review of Maritime and Land-Based Dynamic Environments
Calvin Ser Thong Seah, Wai Leong Eugene Wong, Harry Sze Li Lim, Hiong Yap GanIn-transit additive manufacturing (AM) offers the potential to continue point-of-need production while a host transportation platform remains in motion. Although fabrication has been demonstrated aboard moving maritime platforms, comparable experimental evidence during sustained transit aboard land-based platforms—specifically heavy wheeled vehicles—remains limited. This review examines whether differences in platform dynamic environments may contribute to this asymmetry through interactions between environmental excitation, installed-system dynamics, and fabrication response. A structured narrative synthesis integrates evidence from additive manufacturing, structural dynamics, transportation vibration, and environmental qualification, focusing on maritime vessels and heavy wheeled vehicles as representative platforms, with material extrusion as the principal analytical case. Maritime environments combine low-frequency global vessel motion with higher-frequency machinery, propulsion, hydrodynamic, and transient excitation, whereas heavy wheeled vehicles exhibit suspension- and body-related response alongside broadband road-induced vibration and transient events. Representative material-extrusion structural modes span approximately 10–80 Hz, creating opportunities for spectral coincidence with both environments through distinct excitation mechanisms. Such overlap indicates potential dynamic amplification rather than deterministic degradation, since response also depends on excitation magnitude, damping, transmissibility, boundary conditions, and process-specific disturbance coupling. An environment–structure–process framework is proposed to support vibration-aware characterization and qualification of in-transit AM systems.