Session: 01-06-01: Impact, Fatigue, Damage and Fracture of Composite Structures

Paper Number: 132250

132250 - Low Velocity Impact Response of Hat-Stiffened Composite Coupons 

Stiffeners of various cross-section shapes, such as a hat shaped stiffener, are used to reinforce thin carbon fiber composite structures for carrying compression loading and increasing compressive buckling loads. These structures are lightweight and can meet structural demands for aircraft components. A design limitation for this structure is its relative vulnerability to impact damage. A strike to the surface of the skin of the hat-stiffener can cause delamination within the structure and in severe instances cause the hat to debond from the skin which jeopardizes the load carrying capability of the composite. Quasi-static and impact experiments are performed on various locations of a hat-stiffener coupon and an array of simulations analyze the mesh effects, and sensitivities of cohesive parameters for this structure. Residual stresses are also numerically analyzed to better understand the initiation of delamination. The experiment contains simply supported boundary conditions implemented using steel rollers on the top and bottom faces of the skin away from the bonded flange region. An additional steel roller is placed at various locations along the flange bonding region to determine the worst-case loading scenario. The output of this study will help inform how to accurately capture failure initiation between the skin and hat as well justify the cohesive parameters and requirements on finite element mesh densities.

Presenting Author: Andrew Seamone University of Michigan

Presenting Author Biography: Andrew recently completed his PhD at the University of Michigan while focusing on experimental and numerical analyses of low velocity impact on composites. Today's talk will discuss considerations for LVI modelling on hat stiffened structures.