Biodegradable PLA/PCL Root-Anchoring Structure for Seagrass Restoration: Balancing Hydrodynamic Mitigation and Controlled Seawater Degradation

This study innovatively proposes and fabricates a modular three-dimensional (3D) biodegradable root-anchoring structure (BRAS) (dimensions: 10.5 cm × 12.0 cm × 1.0 cm, α = 60°). It is designed to address the issue that seagrass seedlings are easily displaced by seawater erosion. Fluid–structure interaction (FSI) simulations demonstrate that this design effectively disperses fluid forces. Meanwhile, the design generates stable low-speed wake flows. Additionally, it maintains deformation below 1 cm. The structure is manufactured via selective laser sintering (SLS) technology. Biodegradable polylactic acid/polycaprolactone (PLA/PCL) composite materials are used for fabrication. The study evaluated mass loss, pH changes, microstructure variations, and flexural strength. At a PCL content of 10 wt.%, the composite parts achieve an ideal balance between mechanical properties and controlled degradability. It can match the early establishment cycle of seagrass and provides a comprehensive systematic solution for coastal ecological restoration. This research holds significant implications for seagrass bed restoration and ecological balance maintenance.