# Characterization and Theoretical Analysis of the Venus Flytrap Trigger Hair
## 3 Results and Discussion
### Simulation Analysis of the STHCBM with Abaqus
In addition, when \(E_{2}\) = 500 MPa was fixed, the deflection of the STHCBM decreased with the increase in \(E_{1}\). The results indicate that the deflection of STHCBM remained unchanged when the ratio of \(E_{1}/E_{2}\) overtakes 0.2, which certifies that a higher elastic modulus of the lever and podium reduces the deflection of the trigger hair. However, the maximum strain at the podium of the STHCBM is not affected by the elastic modulus of the lever (\(E_{2}\)), and the maximum values occur at the bottom surface of the podium. As shown in Figure 7a, the deformation area of homogeneous STHCBM (\(E_{1}\) = \(E_{2}\) = 1 MPa) is scattered. On the contrary, there is no strain at the lever of the heterogeneous STHCBM (\(E_{1}\) = 1 MPa \(E_{2}\) = 10 MPa). The strain is mainly concentrated at the podium, and there is an obvious strain 'boundary' (Figure 7b). Obviously, the maximum strain at the podium is related to its elastic modulus, as shown in Figure 7c. When \(E_{2}\) remains constant at 500 MPa, the maximum strain value decreases with the increase in the elastic modulus \(E_{1}\). We can draw the conclusion that when the elastic modulus of the podium is fixed, raising the ratio of the elastic modulus of the STHCBM lever to the podium can effectively reduce the deflection of the trigger hair, and the maximum strain of the podium will not \begin{table}
\begin{tabular}{c c c} \hline \hline
**Samples** & **E1 (MPa)** & **E2 (MPa)** \\ \hline
2 & 1 & 2 \\
3 & 1 & 5 \\
4 & 1 & 10 \\
5 & 1 & 100 \\
6 & 1 & 500 \\
7 & 2 & 500 \\
8 & 5 & 500 \\
9 & 10 & 500 \\
10 & 100 & 500 \\
11 & 500 & 500 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Different material parameter settings (\(L_{1}\) = 5 mm, \(L_{2}\) = 10 mm). be affected. Under the same action of a force, a heterogeneous STHCBM with a high elastic modulus ratio only needs a smaller displacement signal to achieve the same strain concentration effect as a traditional homogeneous STHCBM, and effectively reduces the strain distribution area. Subsequently, the influence of geometric parameters on the mechanical properties of the STHCBM was also worth analyzing. Under the same material parameters (\(E_{1}=1\) MPa, \(E_{2}=10\) MPa), the relationship between the maximum deflection and the length of the podium (\(L_{b}\)) and lever (\(L_{a}\)) is further discussed below (Table 4). Figure 6: The relationship between the deflection of a STHCBM under the same external force and the material parameters: (**a**) maximum deflection of the STHCBM under different elastic moduli of hair lever; (**b**) the relationship between \(E_{2}\) and the maximum deflection under the same \(E_{1}\) (1 MPa); (**c**) the relationship between \(E_{1}\) and the maximum deflection under the same \(E_{2}\) (500 MPa). The simulation results are shown in Figure 8a,b. The results indicate that longer \(L_{b}\) and \(L_{a}\) directly improve the maximum deflection of the STHCBM, respectively. Obviously, when the total length is fixed, the deflection of the larger proportion of the lever length is greater. Figure 8c shows that, under the same concentrated force, the longer the total length, the greater the maximum strain would be at the podium. On the other hand, the maximum stress at the podium increases with the increase in the force. Hence, the change trend of the maximum deflection is consistent with the maximum stress. Cantilever-type sensors can effectively transmit and amplify external input signals, leading to a significant improvement in their performance [24, 25, 26, 27]. Therefore, the principle of optimizing cantilever beam structure is to enhance their response sensitivity to external mechanical signals by reducing strain regions and increasing strain extremes, while ensuring stability. A notch structure inspired by the structure of Venus flytrap trigger hair is introduced here. The minimum diameter of the notch structure is \(d\) = 0.6 mm, and the distance from the fixed end of the podium is \(X_{d}\) = 2 mm, and other parameters remain unchanged.