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数理科学・先端技術研究開発センター(MAT)

セミナーのお知らせ

[MATセミナー開催のお知らせ]

開催日時:
2025年2月5日(水)13:00-15:00
使用言語:
英語
開催場所:
IT 棟 508 MAT シアター
講演者:
多賀 圭理(早稲田大学 先進理工学部 物理学科)
タイトル:
The pattern formation model of the tape-peeling trace by deformed adhesives
概要:
It is known that when adhesive tape is peeled, the structure of the peeling front changes depending on the peeling speed, resulting in various patterns on the peeling trace. At slow peeling speeds, a tunnel structure forms as air penetrates the adhesive fluid of the tape, giving it a white appearance. At fast peeling speeds, this tunnel structure collapses, resulting in a black appearance. Particularly at intermediate peeling speeds, these two structures switch chaotically, forming a fractal pattern of spatiotemporal chaos—an intriguing phenomenon in statistical physics and nonlinear systems. Previous studies have proposed models to explain this pattern formation. However, in this study, we proposed other mechanism and formulate a model based on it. In this talk, we will first introduce our proposed model and discuss how fractal patterns emerge within it. We will then compare our model with previous models to highlight its distinctive features and similarities. Finally, we will explore the proposed model from the perspective of scaling properties. Our results suggest that the tape- peeling trace belongs to the directed percolation universality class.

[MATセミナー開催のお知らせ]

開催日時:
2025年1月15日(水)13:00-15:00
使用言語:
英語
開催場所:
横浜研究所情報技術棟5階508 MATシアター
講演者:
荒川創太 (MAT)
タイトル:
Numerical Investigation on the Compressive Behavior of Hierarchical Granular Piles
概要:
Hierarchical granular piles composed of aggregates are key structural features in both geoscience and planetary science, from fault gouge in seismic zones to the internal structures of comets. Although experimental studies have suggested a multi-step evolution in their packing structure, this hypothesis has lacked numerical validation. In this study, we performed large-scale numerical simulations using the discrete element method to investigate the compressive behavior of hierarchical granular piles. We successfully reproduced and confirmed a three-stage evolution process: (i) rearrangement of the aggregate packing structure, (ii) plastic deformation of small aggregates, and (iii) elastic deformation of constituent particles. Additionally, we developed a semi-analytical model for the compression curve, offering insights into the compressive stages and structural dynamics.