# Optimization Design of Space Camera Enclosure Based on Bionics
## 2 Biomimetic Structural Design
### Structure Design  
The research object of this article is the box structure of a certain aerospace optical camera, and based on this, biomimetic structural optimization design is carried out. The relevant parameters are shown in Table 1.  
Considering the significant impact of the first three levels of veins on the load-bearing performance of the leaves, combined with the growth characteristics of veins mentioned earlier, a reinforced structure for the spatial camera box was designed, as shown in Figure 3. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Parameter Name** & **Parameter Content** & **Unit** \\ \hline Material & TC4 & - \\ Density & 4.451 & g/cm\({}^{3}\) \\ Poisson’s ratio & 0.34 & - \\ Elastic modulus & 110 & GPa \\ Structure size & 900 \(\times\) 600 \(\times\) 220 & mm \\ Weight & 35.116 & Kg \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Optical camera related parameters. Figure 3: Comparison between before and after optimization. Firstly, the overall layout of the bottom stiffeners of the space camera box is determined by analyzing the actual load conditions inside the box. To better achieve the scientific exploration tasks of the space camera, there are three types of loads distributed at the bottom of the camera box, namely the optical imaging system load, the optical polarization system load, and the data acquisition system load, whose positions are shown in Figure 4. Therefore, in order to maximize the stiffness of the bottom of the space camera box, three groups of stiffeners are designed, respectively, with the centers of the three loads as the centers of the bionic structures. Each unit comprises 10 first-level stiffeners, evenly radiating from the center. Linear stiffeners are positioned at the golden section points of the first-level stiffener, serving as a second-level stiffener and forming a 36\({}^{\circ}\) angle with the first-level stiffener in a symmetrical distribution. Concentric circular stiffeners are installed at the golden section points of the first-level stiffener, functioning as a third-level stiffener. The determination of the golden section point is based on the total length of the long strip-shaped reinforcing ribs as the basic data. The product of the total length and 0.618 is the diameter of the first-level circular reinforcing ribs. The first-level circular reinforcing ribs are set. Then, taking the node of the first-level circular reinforcing ribs as the center, the product of the distance from the node of the first-level circular reinforcing ribs to the end of the long strip-shaped reinforcing ribs and 0.618 is the radius of the second-level circular reinforcing ribs. The second-level circular reinforcing ribs are set. This process is repeated for the design. This arrangement aims to enhance overall stiffness and improve the load-bearing capacity. It should be noted that Solidworks-Ansys parametric modeling was employed during the design process. In this paper, the geometric parameters of substrate thickness, stiffener width, and stiffener height are utilized as input parameters for Ansys 2023 R1 software recognition, facilitating subsequent response surface analysis and the search for optimal solutions. The representative significance of these parameters is illustrated in Figure 5.  
Furthermore, static analysis and modal analysis were conducted in Ansys software, with maximum deformation, overall mass, and first-order natural frequency set as output parameters to prepare data for the next response surface analysis and optimization. Figure 4: Box load distribution diagram.