Influence Of The Plastic Zone On The Peak Stress Profile At A Round Hole In A Fiber Metal Laminate

Abstract

Fiber Metal Laminates needs to be seen as a construct of its individual constituents rather than a material on which the industry has capitalized on. Therefore, analytical models must be made in order to predict the mechanical behavior of the laminates which would reduce the big test matrix for defining empirical values for design allowables. An analytical model made to predict the mid-section stress distribution of Fiber Metal Laminate plate with a centre round hole under uni-axial tension. The σ 0 ε-curve of the laminate is defined by the Metal Volume Fraction. Assuming that the elasto-plastic energy of a small strip is equal to the uni-axial imaginary elastic energy, the σ 0 ε-state of these small strips can be calculated. The elastic peak stress profile at the midsection is defined by a decreasing exponential equation with three parameters. The centre of the small strips are the points where the value of interest are determined. Predicting the net-section stress distribution under elasto-plastic loading is determined iteratively by using the Finite Width Correction Factor as a convergence factor between the applied and net-section load. The analytical model gives quite good and accurate results far into the plastic regime validated by DIC experiments and strain gauges. One of the major findings was that indeed it is possible to have delamination and fiber-bridging beneath the plastic zone, which had implications for determining accurately the Blunt Notch Strength.