AN INVESTIGATION OF THE EXISTENCE OF A WORK POTENTIAL FOR FIBER-REINFORCED PLASTIC

Experimental data from axial and torsional deformation tests on inelastic, angle-ply fiber-reinforced plastic laminates and related theory are used to show that mechanical work is independent of path for suitably limited deformation paths, and thus is a potential. First, results from proportional deformation tests are shown to support the existence of a work potential. Domains of path-independence are then established for nonproportional deformation tests of laminates strained well into the range of nonlinear inelastic behavior. Lastly, a study is described in which a work potential-based theory is used to determine critical mixed-mode energy release rates for laminates subjected to axial and torsional deformations. This relatively simple analysis is shown to provide qualitative correlation between fracture surface morphology and calculated energy release rates.