A combined experimental-numerical approach for life analysis and modeling of polymer-based ternary nanocomposite gears

Abstract

The life assessment of polyoxymethylene (POM), POM/carbon black (CB), and POM/CB/nano precipitated calcium carbonate (NPCC) ternary nanocomposite gears was carried out using experimental and numerical techniques. The gear life tests were conducted under constant loading up to failure. Finite element analysis (FEA) was utilized to calculate contact and root stress values. The characterization tests indicated the proper particle-polymer adhesion and the uniform distribution of nanoparticles in the matrix. According to experimental gear tests, POM/CB/3NPCC gears showed the highest lifetime at all applied loads, attributed to synergetic reinforcing effects of CB and NPCC in the POM matrix. The SEM examination of tooth microstructure displayed a smooth surface, characterized by minor indications of surface crack, plastic flow, and debris formation, with the application of 1.5 and 3 wt% NPCC, against pristine POM. The finite element analysis of gears indicated that the single tooth area, during teeth contact, was shorter than the theoretical value. In addition, the contact and root stress values were higher for nanocomposite gears than pristine POM. The experimental and numerical data were applied to obtain the stress-life diagrams for pristine POM and POM nanocomposites and propose a model for life prediction of the gear samples.