In this study, detailed numerical analysis is carried out to investigate the effects of strain hardening on necking improvement by using finite element package ABAQUS. In addition, the response of laminated composite in necking, pure bending and hydroforming is also examined. It is concluded that the necking strain of the composite can be improved by adding high strain hardening constituent materials. Architectured structure, especially corrugated reinforcement is an efficient method to significantly improve necking strain.

When the laminated composite is under tension, the necking strain is proportional to the strain hardening rate and volume fraction of the cladding material. After unloading in pure bending process, compressive and tensile S11 residual stress exist at the top and bottom of the specimen respectively for monolithic material and soft outer layer composites. The residual stress distribution varies according to different material composition. The extent of springback is linearly related to the bending moment.

After the unloading in hydroforming process, tensile and compressive S11 residual stresses are distributed at the top and bottom surfaces of the monolithic specimen. When soft material is cladded at the outer layer of the composite, more compressive residual stress is observed in the cladding. The volume change of the specimen is linearly related to the fluid pressure while the slope of the linear function is independent to the material composition.

Under 2D plane strain tension, corrugated reinforcement is able to provide high strain hardening rate at large strain, and hence significantly improve necking strain of the composite. Small scale corrugation is superior to large scale ones in both necking strain and strength improvement. An optimal scale exists for highest necking strain and strength while further decrease of scale deteriorates the tensile response.

The anisotropic improvement of necking strain by 2D corrugation can be extended to other directions by 3D cone reinforcement. Under plane strain condition, the cone reinforcement is superior to the flat reinforcement in necking strain while remaining comparable strength.