Thermal cycling effects on the structure and physical properties of granular materials

Transient dynamics of the thermally induced deformation of sands

“…All of the discrete numerical studies available show volumetric expansion upon heating regardless of the heating rate. 29,30,[33][34][35] Vertical contraction has also been shown to occur for large differential expansion between the grains and the container. 31 Lastly, the present model relies solely on the mechanical behavior of sand, subjected to loading resulting from the partially restrained thermal expansion.…”

“…The numerical literature on the thermally induced deformation of sands and granular materials at large also corroborates the results of the present study. All of the discrete numerical studies available show volumetric expansion upon heating regardless of the heating rate 29,30,33–35 . Vertical contraction has also been shown to occur for large differential expansion between the grains and the container 31 …”

“…The narrowness of the yield surface characterizes the limited elastic range of sands and is essential to prevent the unrealistic elastic paths corresponding to the crossing of the yield surface during load reversal 54 . Given the small magnitude of the strains involved with the thermally induced deformation of sands and because no such elastic evolution is observed at the transition between the heating and cooling phases in experimental or DEM studies, 25,29 a small value of $$m = 0.001$$ is selected in the present work, along with the default value of $$n = 20$$.…”

“…[9][10][11][12][13][14][15][16][17] For coarse-grained soils (e.g., sand), thermal expansion of individual grains, which alters the contact force network and causes grain rearrangement, has been considered responsible for the thermally induced deformation of such materials within the same temperature range. [18][19][20][21][22][23][24][25][26] This peculiar nature of thermally induced deformations in coarse-grained soils has been supported by theoretical, 27 experimental, 28 and numerical evidence resorting to particle-scale simulations, [29][30][31][32][33][34][35][36] considering clean sands pertaining to classes SW or SP (i.e., wellgraded and poorly graded gravelly sands, with little or no fines) according to the Unified Soil Classification System, for which there is no potential influence of the plasticity of fine grains and their chemo-physical interaction with water.…”

Down-hill creep of a granular material under expansion/contraction cycles

“…Along a different line of investigation there has also been rather intense work on the effect of oscillatory temperature changes on a pile of granular material. [24][25][26][27][28][29] Here also the effect of temperature is primarily considered to affect the size of the particles due to the thermal expansion effect. In turn, this size change can produce rearrangements of the contact network between grains, which was observed to lead to a compaction of the pile as a function of the number and amplitude of cycles of temperature variation.…”