Influence of non-plastic siliciclastic coating on the monotonic and cyclic contact behavior of granular systems
摘要
We examined the influence of siliciclastic coating on the tribological behavior of sand particles. A new coating method was developed for this purpose, which is based on the principle of precipitation, allowing for a fairly uniform distribution of the microparticles to be developed, achieving a higher consistency of the test results in the normal and tangential directions to particle contacts. The investigation included both monotonic and cyclic tests as well as the application of preloading in some of the experiments. Particular emphasis was placed in the data analysis including contact Young’s modulus, coefficient of friction, contact stiffness in the normal (KN) and tangential (KT) directions and the stiffness ratio (KN/KT), as well as the analysis of elastic and plastic fractions of displacement, work done and the energy dissipation at the contacts of the particles. While the siliciclastic coating had a major influence on the contact stiffness and friction, the mechanisms of friction would be rather controlled by both the interlocking and inference of the microparticles as well as asperity interlocking of the sand grains, as revealed from post-shearing image observations. Overall, the contact behavior and the role of microparticle coating may be considered a key in understanding the meso- and macroscopic mechanics of granular systems and the mechanisms of energy dissipation.
Graphical Abstract