Design Integration, Workability, Acoustic and Mechanical Characterisation of Wood-Based PLA Composite Panels for Prefabricated Façade System

This paper reports the development and multi-dimensional experimental characterisation of post-consumer wood-based PLA (PCW-PLA) composite panels for prefabricated façade systems, presenting results across a panel design and four sequential assessment phases during early-stage development activities: design integration, manufacturing workability, acoustic characterisation, and mechanical performance. Two panel typologies were investigated: solid panels (5 mm, compression moulding) and honeycomb panels (9 mm total thickness: 2 mm face sheets with 5 mm hexagonal core, FDM additive manufacturing), benchmarked against conventional market-reference products across four prefabricated façade configurations. Phase 1 (design integration) confirmed thermal equivalence across all configurations (U = 0.35-0.158 W/m²·K per ISO 6946), within the gate criterion of ΔU ≤ 10%. Phase 2 (manufacturing workability) established that conventional on-site tools are incompatible with the material's hardness characteristics, constraining the product to off-site prefabrication, with CNC milling as the optimal route. Phase 3 revealed that the honeycomb panel achieves broadband sound absorption α = 0.40-0.55 at 1500-3500 Hz, qualitatively distinct from the solid configuration (α < 0.05 broadband). At façade system level, FS-W2W-01 achieves insertion loss 26-35 dB across 100-2000 Hz; FS-W2W-02 exhibits resonance instability at ~750 Hz and ~1200 Hz, hypothesised to originate from local mass-spring-mass coupling within the honeycomb stratigraphy, requiring acoustic design optimisation. Phase 4 characterised the honeycomb panel: bending strength fm,mean = 15.5 N/mm², modulus of elasticity E = 2640 N/mm², and internal bond ft,mean = 0.34 N/mm² (CoV ≈ 38%), with face/core interface bonding identified as the critical development parameter. The results confirm the technical feasibility of PCW-PLA composite panels for prefabricated façade applications at TRL 3–4, establishing thermal equivalence with market-reference systems, off-site CNC manufacturing as the only viable production pathway, and broadband acoustic absorption of the honeycomb geometry as the primary differentiating performance characteristic. Limitations inherent to the TRL 3–4 context – prototype material quantities, non-standard test configurations, and indicative mechanical results – are documented alongside phase outcomes and identified as development priorities for next-TRL advancement.