Mechanical properties of homogeneous and functionally graded spinodal structures

This paper investigates the compressive mechanical behavior of spinodoid metamaterials in a quasi -static state through experimental and numerical analysis at the macroscopic level. This homogeneous structure exhibits weak strain hardening, resulting in a lower initial peak compression force and higher specific absorption energy compared to other mechanical metamaterials. The homogeneous model has multiple low -density regions uniformly distributed within the three-dimensional space due to the random nature of the Gaussian field. Thus, the transition from low -density to high -density regions is described as a gradual process, implying that the deformation of metamaterial shifts to region -by -region compaction. Besides, the functionally graded spinodoid structure shows strong strain hardening, whose deformation mainly tends to collapse layer by layer along a positive graded direction. The graded structures with low densities have a lower energy absorption capacity than the corresponding homogeneous structure, while higher -density structures show a reverse trend. This phenomenon originates from the superimposed effect of two kinds of strain hardening.