Fig. 3. FE analysis.

The mechanical reliability of the computational wrapping of the Si wafer shown in Fig. 2F is further investigated through FE simulations for wrapping a part of a sphere. (A) The wrapping process is simulated by compressing the 2D nonpolyhedral developable net between the sphere and a concave mold of a wrapped part of the sphere (see also movie S2). The radius of the sphere in the FE simulation is identical to that used in our experiment (Fig. 2F). (B) The nonpolyhedral developable nets are generated by the GA method. The distributions of the maximum in-plane principal stress for the wrapped Si wafers are analyzed (C) with respect to the number of meshes at a fixed thickness of 20 μm and (D) with respect to the thickness at 400 meshes. Consequently, the maximum in-plane principal stress decreases as the number of meshes increases and increases as the thickness increases (E and F). In both cases, the maximum stress values are much smaller than the fracture strength of the Si wafer.