Theoretical evaluation of mechanical properties of inverse opal structure

DOI: 10.62564/M4-PK2254

Pavlo Korobko¹, Andrii Kuzmov<sup>1,2

1</sup>Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine
²National Technical University of Ukraine «Igor Sikorsky Kyiv Polytechnic Institute»


The study focuses on the theoretical evaluation of the mechanical properties of porous materials with an inverse opal structure which serves as the object of the study. The subject of the study is the process of transition from elastic to irreversible deformation. The purpose of this study is to apply the finite element method to model this process to reveal the relationship between the structural characteristics of materials, such as porosity and coating thickness, and their mechanical properties [1]. The yield surface was constructed by computational modelling on a representative cell with a number of points in the (p,τ) plane for several cases of inverse opal structure - for a highly porous uncoated structure and structures with an additional layer [2]. As a result of the study, yield surfaces of the structure under investigation were constructed for several porosity values, from 0.56 to 0.9. In the result of the work, the approximation of the numerical appearance of the yield surface by a Deshpande-Fleck crushable foam model available in finite element modelling packages was made [3]. The conclusions of the study show that the effective plastic properties of materials with an inverse opal structure significantly depend on their porosity level and the presence of additional coatings. The obtained yield curve for a porosity of 0.9 is close to the associated plastic flow law, which allows us to assess the material's behaviour under loading based on the results of the uniaxial stress state. However, for a structure with medium porosity and an additional coating layer, the surface becomes significantly unassociated, with a discrepancy of almost 30%. The application of the Deshpande-Fleck model for crushable foam in the approximation of the obtained numerical data from the study demonstrated the relevance of the model in describing the plastic behaviour of this structure only at high porosity values.

Keywords
micromechanics, metamaterials, inverse opal

Acknowledgments
This research was part of P. Korobko’s PhD study which is carried out under the state order.

References
[1] Bakhvalov N.S., Panassenko G.P. Upscaling: Averaging Processes in Periodic Media. Kluwer Academic Publishers, 1989 [2] Christensen R.M. Mechanics of Composite Materials. Wiley-Interscience, New York, 1979. 348 p. [3] Pikul J.H., Özerinç S., Liu B., Zhang R., Braun P.V., Deshpande V.S., King W. P. High strength metallic wood from nanostructured nickel inverse opal materials. Scientific Reports. 2019. No. 719