Bioinspired topology-physical-field co-driven design of multi-morphology TPMS lattices for load-bearing and thermal insulation

The trade-off between load-bearing capacity and thermal insulation limits lightweight multifunctional structures requiring both mechanical support and thermal protection. Inspired by the three-layer architecture of pomelo peel, this study proposes a bioinspired topology-physical-field co-driven (BT-PF) strategy for designing Ti-6Al-4 V heterogeneous triply periodic minimal surface (TPMS) lattices. The steady-state temperature-gradient inflection points extracted from a selected Gyroid reference model were used to partition the design domain, after which Gyroid, IWP, and Diamond unit cells were assigned to different functional regions through field-driven mapping to construct DGI, GID, and IDG multi-morphology lattices. The lattices were fabricated by laser powder bed fusion (LPBF) and evaluated separately by room-temperature compression tests, unloaded thermal-insulation tests and finite element simulations. The results show that topology sequence and volume fraction jointly regulate deformation stability, stress redistribution, energy absorption, and temperature attenuation. IDG-28 and IDG-34 balance load-bearing and thermal-insulation performance under the respective test conditions, while GID-28 provides the highest specific energy absorption within the 28% group. Compared with homogeneous Gyroid lattices, the heterogeneous designs suppress localised shear-band propagation, improve stress distribution and increase the steady-state temperature difference. This work provides a field-informed design route for multifunctional TPMS lattices requiring both load-bearing and thermal-insulation functions.