I am a SNSF postdoctoral researcher in Bertoldi group at Harvard School of Engineering and Applied Sciences. I am working in the general area of mechanics of materials with a focus on designer matter to create new architected materials with novel functionalities. In my research, I get inspirations from natural and biological systems, origamikirigami and architecture.

I'm currently on the job market for both academia and R&D industry. 

Recent Publications

Buckling-Induced Kirigami
A. Rafsanjani and K. Bertoldi. 2/24/2017. “Buckling-Induced Kirigami.” Physical Review Letters, 118: 084301. Publisher's Version Abstract

We investigate the mechanical response of thin sheets perforated with a square array of mutually orthogonal cuts, which leaves a network of squares connected by small ligaments. Our combined analytical, experimental and numerical results indicate that under uniaxial tension the ligaments buckle out-of-plane, inducing the formation of 3D patterns whose morphology is controlled by the load direction. We also find that by largely stretching the buckled perforated sheets, plastic strains develop in the ligaments. This gives rise to the formation of kirigami sheets comprising periodic distribution of cuts and permanent folds. As such, the proposed buckling-induced pop-up strategy points to a simple route for manufacturing complex morphable structures out of flat perforated sheets.

Bistable Auxetic Mechanical Metamaterials Inspired by Ancient Geometric Motifs
A. Rafsanjani and D. Pasini. 12/2016. “Bistable Auxetic Mechanical Metamaterials Inspired by Ancient Geometric Motifs.” Extreme Mechanics Letters, 9: 291-296. Publisher's Version Abstract

Auxetic materials become thicker rather than thinner when stretched, exhibiting an unusual negative Poisson’s ratio well suited for designing shape transforming metamaterials. Current auxetic designs, however, are often monostable and cannot maintain the transformed shape upon load removal. Here, inspired by ancient geometric motifs arranged in square and triangular grids, we introduce a class of switchable architected materials exhibiting simultaneous auxeticity and structural bistability. The material concept is experimentally realized by perforating various cut motifs into a sheet of rubber, thus creating a network of rotating units connected with compliant hinges. The metamaterial performance is assessed through mechanical testing and accurately predicted by a coherent set of finite element simulations. A discussion on a rich set of mechanical phenomena follows to shed light on the main design principles governing bistable auxetics.

Hierarchies of Plant Stiffness
V. Brulé, A. Rafsanjani, D. Pasini, and T. L. Western. 9/2016. “Hierarchies of Plant Stiffness.” Plant Science, 250: 79-96. Publisher's Version Abstract

Plants must meet mechanical as well as physiological and reproductive requirements for survival. Management of internal and external stresses is achieved through their unique hierarchical architecture. Stiffness is determined by a combination of morphological (geometrical) and compositional variables that vary across multiple length scales ranging from the whole plant to organ, tissue, cell and cell wall levels. These parameters include, among others, organ diameter, tissue organization, cell size, density and turgor pressure, and the thickness and composition of cell walls. These structural parameters and their consequences on plant stiffness are reviewed in the context of work on stems of the genetic reference plant Arabidopsis thaliana (Arabidopsis), and the suitability of Arabidopsis as a model system for consistent investigation of factors controlling plant stiffness is put forward. Moving beyond Arabidopsis, the presence of morphological parameters causing stiffness gradients across length-scales leads to beneficial emergent properties such as increased load-bearing capacity and reversible actuation. Tailoring of plant stiffness for old and new purposes in agriculture and forestry can be achieved through bioengineering based on the knowledge of the morphological and compositional parameters of plant stiffness in combination with gene identification through the use of genetics.

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