  The trade-off between strength and ductility has plagued the design of
macroscopic assemblies of two-dimensional materials for a long time. In order
to break the strength-ductility paradox, the design of self-folded
two-dimensional nanomaterial (SF-2DNM) has been recently proposed with the
inspiration from the folded nanostructures of natural silks. Such folding
strategy is revealed to greatly enhance the ductility of overall assembly
without much sacrifice of the excellent tensile strength of two-dimensional
materials. However, the dependences of the elastic properties of SF-2DNMs on
the material properties of building blocks and the geometries of folded
structures have not been specifically clarified in previous studies. In this
paper, we thus develop a theoretical model to describe the elastic properties
of SF-2DNMs based on the shear-lag analysis. The load transfer behaviors and
failure modes of SF-2DNMs are demonstrated with this model. The Young's modulus
and tensile strength of SF-2DNMs are also predicted, further validated by
molecular dynamics simulations. This model brings insights into the elastic
deformation of SF-2DNMs under external tension. The structure-property
relationship revealed by this model would provide useful guidelines for the
rational design of SF-2DNMs in engineering applications.
