# State of the Art Review about Bio-Inspired Design and Applications: An Aerospace Perspective
## 3 Review on Manufacturing Methods Used in Bio-Inspired Design
\begin{table}
\begin{tabular}{c c c} \hline
**Research Work** & **Contributions** & **Inferences** \\ \hline [PERSON] et al. [25] & Investigation of T joint performance & Toughening mechanisms in tree branch joints \\ \hline [PERSON] [24] & Bio-inspired Composites & Use of AM technique in Bio-inspired \\ \hline [PERSON] et al. [33] & Fabrication of nano-graphene composites & Utilization of skin structure for material design \\ \hline [PERSON] et al. [26] & Honeycomb structure under impact loading & Honeycomb structure (with circular tubes) is the best \\  & & under impact loading by changing the structures’ height. \\ \hline [PERSON] et al. [27] & Structural effects on ABS in nanostructure mixture & Impregnating CNC on ABS, inspired by wood \\ \hline [PERSON] et al. [28] & Design method for bio-inspired structure & Using FEA to optimize bio-inspired structures \\ \hline \end{tabular}
\end{table} 
Table 2: Review of Materials used in Bio-inspired design. The constraints were further considered during manufacturing. The ideation to the design phase was solely dependent on experimentation [41]. This provided a synergistic system for bio-inspired applications. The research in bio-inspired design is inclined towards sustainable development, and this research methodology was implemented in the laser-based systems shown in Figure 10[42]. The majority of the optimum ways of manufacturing bio-inspired design is multilayered architecture [43]. They have higher energy absorption and hit capacity, which was increased by subsequent adhesion. Alternatively, fire-resistant properties were also noted using AM techniques. The GAP methodology establishes it for the design and manufacturing process. An extensive GAP method is shown in Figure 11, which implemented a product development cycle for bio-inspired processes. Figure 8: Additive Manufacturing Methods [28]. Figure 7: A framework for the application of biomimicry [37]. Figure 11: GAP Methodology [44]. Figure 10: Research Methodology [42]. Figure 9: Procedure for AM testing [28]. CNC's infusion (cellulose nanocrystal) to print a composite structure [45]. The infill in ABS and the impregnation of CNC even at 100% infill opened new avenues for AM techniques. The bio-inspired design also inspired new frontiers in AM, including the gravo-elastic scaling using bio-inspiration [46]. The method emphasized the gravitational and aeroelastic scaling, it aimed at aeroelastic, centrifugal, and gravitational load acting on the load. The scaling-up process was followed by a ground testing method, with the blade structural scaling error. Along with the AM methods, optimization techniques such as TO, generative design, and shape optimization can be used [47]. Selective laser melting (SLM) techniques were used for the Ti-6 Al-4 V fabrication. The compression testing was more efficient than conventional methods; it had strength beyond 300 MPa. Similarly, [PERSON] et al. highlighted the mechanical properties of a bio-inspired tool path [48]. The parallel scan method was used for contour crafting, which involved printing honeycomb and nacre structures and assisted by FEA analysis. The growth in composite materials has increased in the past decade, which serves as an optimum technique for printing bio-inspired materials [44]. Toughness and strength were increased to 12% and 100%. The two main methods followed are given in Figure 12.  
The SLM techniques provide 10% more accuracy in designing corrugated, triangular, and square panels. Similarly, corrugated sandwiches with foam-related substances and metals with conventional structures sustained more shock and loading absorption [49]. One of the key features to be noted is the performance trade-offs for 3D printed designs, as shown in Figure 13. These represent the basic building blocks of bio-inspired materials, varying from brick mortar, concentric hexagon, cross lamellar, and rotating plywood [50]. In recent years, in combination with FEM techniques, the corrugated structures can aid homogenization [51].