Elasto-plastic analysis of influences of bond deformability on the mechanical behavior of fiber networks

Micromechanical modeling of three-dimensional (3D) fiber networks is performed by reducing the web structure to fiber segments and fiber–fiber bonds to explore the influence of fiber–fiber bond deformability on fiber network’s elasto-plasticity. The fiber segment between every two adjacent bonds is described by a Timoshenko beam element, while fiber–fiber bonds are taken as a different two-node element due to the extremely large height-to-span ratio. This overcomes the rigid-bond assumption employed by most previous network models, providing the feasibility to build the relationship between bonding condition and global mechanical properties, resulting in a 3D network structure and able to accommodate curled fibers. Both fibers and bonds are assumed to be elasto-plastic and described by the bilinear kinematic hardening model. Deformation of the network with load increasing is simulated by the Newton–Raphson method. Numerical tensile tests show reasonable results and agree qualitatively with experiments. The influence of bond deformability on the mechanical behavior of the network is discussed in detail.