Enhanced mechanical and acoustic performance of layered metal-mesh eucalyptus multi-ply structures

The mechanical and acoustic performances of five-layer eucalyptus plywood reinforced with copper and stainless steel meshes were studied, focusing on the effects of mesh type, layer count, and mesh size. Experimental results demonstrated that incorporating metal mesh significantly enhanced both mechanical properties and acoustic vibration characteristics. The mechanical performance peaked at two-layer reinforcement configurations, with static elastic modulus values reaching 8,570 MPa (copper) and 9,100 MPa (steel), while mesh size exhibited negligible influence. Acoustic metrics, including acoustic conversion efficiency (ACE) and specific dynamic elastic modulus (Esp), also achieved optimal values in two-layer composites, with copper outperforming steel (e.g., ACE: 248 vs. 213). Notably, copper composites exhibited superior vibrational energy retention, with a minimum loss tangent of 0.0259, compared to 0.0246 for steel. The findings highlight that layer count, rather than mesh size or type, dominated performance optimization. Two-layer configurations balanced interfacial stress distribution and bonding efficiency, yielding the highest mechanical and acoustic outputs. These metal-reinforced composites offer sustainable alternatives to traditional tonewoods reducing reliance on endangered species while enabling cost-effective utilization of low-grade timber. Their enhanced acoustic-mechanical synergy positions them as promising materials for musical instruments, home audio systems. This work provides actionable insights for eco-friendly material design in industrial and musical applications.