14:15 〜 14:30
[PPS02-02] Modelling and discrete element analysis of penetration resistive force into cohesive granular materials
キーワード：粒状体、貫入抵抗力、離散要素法
Recent exploration missions have revealed that many solid bodies, including asteroids, are covered with granular materials called regolith. On these surfaces, it is important to understand resistive forces when an object penetrates and impacts into the regolith to predict the behavior during touchdown of planetary explorer [1] and travel of exploration rover [2]. Various studies have investigated penetration and impact resistive force into granular materials. However, most of them have focused on the resistive force in the case of dry state [3,4]. The granular materials covering on Earth and planetary bodies such as the Moon and Mars generally have cohesion between particles. Therefore, the penetration resistive force on cohesive granular materials should also be considered to improve the prediction accuracy for explorer behaviors.
In this study, we develop a model for penetration resistive force on cohesive granular materials and validate the model through cone-penetration tests simulated by Discrete Element Method (DEM). For the model of penetration resistive force on cohesive granular materials, we extend the model proposed in the previous study [4] to include cohesion forces between particles. The derived model for penetration resistive force on cohesive granular materials is composed of the sum of the friction-originated force proportional to the penetration volume and the cohesion-originated force proportional to the penetration cross-sectional area. In addition, we carry out cone penetration simulations for wet sand, a kind of cohesive granular material. We validate the model by comparing the model result with numerical results. As a results, we reveal that the influence of the stagnant zone formed in front of the cone must be taken into account, even in the case of dry granular materials, to explain the resistive forces during cone penetration. Through this modification depending on the stagnant zone, the model derived in this study can properly predict the penetration resistive force into both dry and wet granular materials.
[1] Walsh et al., Sci. Adv. 8, eabm6229 (2022)
[2] Suzuki et al., Soil Tillage Res. 226, 105578 (2023).
[3] Li et al., Science 339, 6126 (2013).
[4] Kang et al., Nat. Commun. 9, 1101 (2018).
In this study, we develop a model for penetration resistive force on cohesive granular materials and validate the model through cone-penetration tests simulated by Discrete Element Method (DEM). For the model of penetration resistive force on cohesive granular materials, we extend the model proposed in the previous study [4] to include cohesion forces between particles. The derived model for penetration resistive force on cohesive granular materials is composed of the sum of the friction-originated force proportional to the penetration volume and the cohesion-originated force proportional to the penetration cross-sectional area. In addition, we carry out cone penetration simulations for wet sand, a kind of cohesive granular material. We validate the model by comparing the model result with numerical results. As a results, we reveal that the influence of the stagnant zone formed in front of the cone must be taken into account, even in the case of dry granular materials, to explain the resistive forces during cone penetration. Through this modification depending on the stagnant zone, the model derived in this study can properly predict the penetration resistive force into both dry and wet granular materials.
[1] Walsh et al., Sci. Adv. 8, eabm6229 (2022)
[2] Suzuki et al., Soil Tillage Res. 226, 105578 (2023).
[3] Li et al., Science 339, 6126 (2013).
[4] Kang et al., Nat. Commun. 9, 1101 (2018).