Characterization of elastic-plastic and viscoplastic behavior of AS4/PEEK thermoplastic composite
Abstract
The elastic-plastic and strength properties of AS4/PEEK (APC-2) thermoplastic composite were characterized with respect to temperature variation by using a one parameter plasticity model and the elastic-viscoplastic properties were characterized by using a one parameter overstress viscoplasticity model and a modified Bodner and Patom's viscoplasticity model. To obtain the elastic-plastic and strength properties, simple uniaxial off-axis tension tests were performed on coupon specimens of unidirectional composite at various temperatures. To determine the strain rate effects, uniaxial tension tests were performed on unidirectional off-axis coupon specimens with different monotonic strain rates. To avoid the complication caused by the extension-shear coupling effect in off-axis testing, new tabs were designed and used on test specimens. These plasticity and viscoplasticity models were verified further for the case of unidirectional composite panels with cutouts and in laminates with and without hole. The nonlinear stress-strain relations were measured and compared with those predicted by the finite element analysis of which elastic-plastic constitutive relations were derived based upon a one parameter plasticity model.
Degree
Ph.D.
Advisors
Sun, Purdue University.
Subject Area
Aerospace materials
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