Natural materials are formed with integral structures.Based on the achievements of our predecessors,the microstructures of some natural materials were decoded,and the configurations of integrated structures were interpreted with graded,porous,fractal and composite forms.The composition and spatial gradients of multiple kinds of physical parameters,which included elastic modulus,hardness,surface tension,stiffness,damping factor,density,heat conduction,electrical resistance factor,magnetic conductive factor,light penetration factor etc,are summarized.The 2-D and 3-D porous structures were analyzed,which had different types of voids and configurations.Then the fractal and gradient fractal rules were described with leaf structure.Moreover,the particulate and fibrous composite structures were developed with the combination of graded,porous and fractal rules.Finally,complex bionic design based on nets of blood vessels and nerves were proposed,which could be applied in structure design of mechanical parts.
