Performance characterization of an additively manufactured mechanical structure produced in single and multiple materials with varying configurations

Nowadays light weighting is gaining increasing importance to minimize fuel consumption and improve flight endurance of aerial and space vehicles. The present study aims to apply multi-material additive manufacturing to achieve the mentioned objective in a wing spar without compromising its structural integrity. For concept proofing, two polymer-based materials namely Acrylonitrile Butadiene Styrene (ABS) and Carbon Fiber reinforced Polylactic Acid (CF-PLA) were employed for printing a wing spar in single and multiple materials with varying configurations. Given larger bending stresses on the outer surfaces, the outer structure of the spar was printed in CF-PLA as it has higher strength. However, the inner structure, i.e., close to the neutral plane, was printed in low-density ABS thereby resulting in high strength-to-weight ratio wing spars. The performance of the printed spars was tested in terms of load-to-weight ratio, stiffness-to-weight ratio, and energy absorbed. The results revealed that the multi-material spars interestingly exhibited improved performance, which compared with that of the ABS spars was 109 % greater in terms of load-bearing capacity and 76 % better in terms of energy absorption ability. The suitability of Finite Element Analysis (FEA) to simulate the performance of spars was also examined. The numerical results were in good agreement with the experimental ones thereby confirming that the FEA can be employed as a reliable tool to test and tailor the performance of any multi-material spar without performing experiments.