In-Plane Tensile Behavior of Sintered Fibrous Copper Systems Using Ball Chain Modeling

The present study investigates the relationship between 3D microstructure and macroscopic mechanical performance of porous copper fiber sintered felt. The sintered junctions at fiber-to-fiber crossovers play an important role in the mechanical stiffness of the fiber system. Therefore, to reconstruct the fibrous network model with controllable geometry details at fiber-to-fiber sintered junctions, the fiber system is modeled using a force-based packing approach to represent fibers as chains of balls. Different levels of overlapping between fibers are modeled by varying the factor parameter controlling distance of balls at junctions of different fibers. By gradually increasing the distance parameter, the fibers in fiber mat will reach the critical state between connected (overlapped) and separated, and the critical factor value which barely keeps the integrity of geometry model was obtained. The virtual models are then used for in-plane tensile simulations using finite element method. By introducing the failure criteria, the tensile deformation process involving the tensile strength and critical elongation of fiber system is captured and compared with experimental results. The simulated data are similar to the measured data in magnitude, shape and 2% critical elongation of the stress-strain curves. Numerical analysis allows the investigation of effect of fiber junctions on mechanical strength which decreases dramatically as fiber overlapping decreases. The most approximate data appear at virtual model using the critical distance value and thus indicate a weak mechanical stiffness of the sintered junction.