Micromechanics of the internal bond in wood plastic composites: integrating measurement and modeling

In this study, an integrated approach combining experimental measurements and numerical modeling was used for characterization of load transfer in the wood/matrix interface in wood plastic composites (WPCs). The experimental methodology was based on optical measurement of surface displacements and strains in model WPC specimens subjected to tensile loads. The model specimens consisted of thin HDPE films with single embedded wood particles. The optical measurement of surface strains was based on the digital image correlation principle. The material point method was used for morphology-based numerical modeling of the loaded specimens. The exact location and morphology of the embedded particle determined by X-ray computed tomography were used as input for the numerical model. Imperfect interface characteristics, reflecting the efficiency of the load transfer through the interface in the numerical model of the composite, were determined using inverse problem methods. Good agreement was obtained between the simulated and measured strain maps determined on a number of specimens including particles with various orientations to the loading direction using the same values of interface parameters.