Computational/experimental characterization of recycled plastic extrusions with reinforcement

Experimental characterization of time-independent and time-dependent (creep) properties for rectangular hollow-cored, fiber reinforced, commingled recycled plastic extruded forms (RFCRPE) has been a primary focus of this research. Finite element based computer models have been developed to predict the effects of damage progression in such reinforced extruded plastic forms.; Static and creep flexural testing were performed to determine short- and long-term (life cycle) properties. Reinforced extrusions with varying compositions were used as specimens. In the creep tests these extrusions were submerged in heated water and subjected to different loads and temperatures. Note that the combined “static” and “creep” flexural tests comprise the bulk of the experimental data used for finite element model validation. Fiber pull-out tests were conducted to better understand fiber-matrix interfacial strength. Tests were performed to ASTM standards where possible, and a creep test apparatus was built and used to conduct temperature-controlled fully submerged creep tests. Experimental results demonstrate that fiber micro-buckling and fiber-matrix interface failure occur during the static and creep loading environments. Experimental data indicates that these damage modes significantly reduce both short- and long-term (life cycle) properties.; “Damage dependent” finite element models were developed using different material property types to represent the glass fiber roving, fiber-matrix interface and plastic matrix respectively. Material nonlinearity of the plastic matrix has been incorporated along with stress-based failure criteria to account for fiber-matrix interfacial shear failure and local fiber micro-buckling. A user-defined subroutine, part of an industry standard finite element software package, has been modified to accommodate the damage progression. The developed finite element based model(s) have correlated well with both short- and long-term test results, and can provide a “design tool” in predicting fiber micro-buckling and fiber-matrix interfacial shear failure associated with future to-be-studied composite extrusions/forms.