Fiber Pull-Out: Interfacial Debonding & the Kelly-Tyson Model

Pull a single reinforcing fiber out of a transparent matrix block and watch fiber-matrix load transfer play out exactly as the shear-lag (Kelly-Tyson) model predicts: an elastic loading ramp, an interfacial debond front that sweeps down the embedded length at roughly constant load, and then a frictional pull-out stage where the force falls linearly as the fiber slides free. Choose glass, carbon or aramid fiber, set the embedded length and interfacial shear strength, and the simulation compares the debonding force against the fiber's own breaking strength in real time — cross the critical embedded length and the fiber snaps instead of pulling out, the failure-mode switch that governs how short-fiber composites are designed for toughness.