Acoustic emission characteristics of waste fiber‐reinforced recycled high‐density polyethylene composites under damage conditions

Abstract Acoustic emission (AE) technology provides a novel approach for studying the damage and fracture behavior of wood‐plastic composites (WPCs) during their application process. This method allows rapid and precise analysis of the mechanical properties of materials, which is a significant advancement for the emerging WPC industry. Hence, a blend of waste floor sanding powder (FSP) and rice husk (RH) reinforced recycled high‐density polyethylene (Re‐HDPE) was prepared by the extrusion method. The AE technique, scanning electron microscopy, and finite element method (FEM) were used to analyze the damage and fracture behavior of the composite materials under a three‐point bending test. The results indicated that the bearing capacity of RH/Re‐HDPE composites was slightly higher than that of FSP/Re‐HDPE composites. The AE technique can better illustrate the damage evolution and fracture process of composites and determine the damage degree and mode. Matrix cracking and deformation were more pronounced in the FSP/Re‐HDPE composites. Fiber breakage and delamination were more prominent in the RH/Re‐HDPE composites. In addition, repeated loading caused irreversible damage to the composite. The increase in temperature led to the attenuation of the AE signal and a decrease in matrix strength. However, when the temperature reached a certain point, the cumulative AE ringing count increased again because the higher temperature improved the fiber–matrix interface strength, which partially canceled out the negative effect. In addition, Abaqus was used for simulation analysis, and the running results coincided with the experimental value. Highlights RH/Re‐HDPE and FSP/Re‐HDPE are sustainability and low‐cost composites. AE can determine the degree and mode of damage of WPC at different temperatures. The AE curves of RH/Re‐HDPE and FSP/Re‐HDPE all pass through four stages. Heating reduced the matrix strength and improved the interface strength of WPC. The results of FEM were consistent with the experimental results.