Astronomical collision energy and momentum transport processes based on the rheological constitutive law of granular material

JAXA Supercomputer System Annual Report February 2025-January 2026

Report Number: R25EACA67

Subject Category: JSS Inter-University Research

Responsible Representative: Kiwamu Yoshii, Assistant Professor, Tokyo University of Science
Contact Information: Kiwamu Yoshii(qyoshii@rs.tus.ac.jp)
Members: Sota Arakawa, Kiwamu Yoshii

Abstract

This study aims to clarify the physics that determines the efficiency of orbital deflection of small bodies by hypervelocity impact. In particular, we focus on the initial porosity of the target bodys surface layer, the compaction behavior of pores, and the shear strength of fragmented granular material after disruption, and investigate how these factors affect energy and momentum transfer. By comparing numerical simulations with experimental and observational data, we seek to advance numerical models and establish an impact response model that contributes to planetary defense.

Reference URL

N/A

Reasons and benefits of using JAXA Supercomputer System

Hypervelocity impact is a complex phenomenon involving strong coupling among shock propagation, pore compaction, fracture, granular flow, and ejecta production, and thus requires high-resolution three-dimensional simulations and large-scale parameter studies. The JAXA Supercomputer is therefore essential for conducting this research efficiently and for validating the models through comparison with experimental and observational data.

Achievements of the Year

This fiscal year, we worked on the part of the project concerning the shear strength of granular materials and advanced the study of constitutive laws for sheared granular media, including the \mu(I) rheology. In particular, we extended constitutive laws for ordinary granular materials to particle systems with a simple attractive-force model. We then incorporated the resulting constitutive law into the continuum equations, thereby establishing a basis for future continuum analyses and impact simulations.

Fig.1: Numerical setup used to investigate the constitutive law of granular materials. A shear flow is generated by applying a normal load from the top while driving the top boundary horizontally, and the rheology of the granular layer is examined. The particle color indicates the normalized vertical position.

Publications

- Peer-reviewed papers

Kiwamu Yoshii, Takenobu Nakamura, Michio Otsuki

"Yielding transition of stress controlled granular materials near jamming"

EPJ Web of Conferences: Powders & Grains 2025 340, 04003 (2025).

- Oral Presentations

Kiwamu Yoshii, Michio Otsuki

"Jamming of weakly cohesive granular flow between parallel plates"

(DEM10)The 10th International Conference on Discrete Element Methods

Usage of JSS

Computational Information

Process Parallelization Methods: MPI
Thread Parallelization Methods: N/A
Number of Processes: 32
Elapsed Time per Case: 10 Hour(s)

JSS3 Resources Used

Fraction of Usage in Total Resources*1(%): 0.00

Details

Please refer to System Configuration of JSS3 for the system configuration and major specifications of JSS3.

Computational Resources
System Name	CPU Resources Used (Core x Hours)	Fraction of Usage*2(%)
TOKI-SORA	0.00	0.00
TOKI-ST	5285.06	0.01
TOKI-GP	0.00	0.00
TOKI-XM	0.00	0.00
TOKI-LM	0.00	0.00
TOKI-TST	0.00	0.00
TOKI-TGP	0.00	0.00
TOKI-TLM	0.00	0.00

File System Resources
File System Name	Storage Assigned (GiB)	Fraction of Usage*2(%)
/home	0.00	0.00
/data and /data2	0.00	0.00
/ssd	0.00	0.00

Archiver Resources
Archiver Name	Storage Used (TiB)	Fraction of Usage*2(%)
J-SPACE	0.00	0.00

*1: Fraction of Usage in Total Resources: Weighted average of three resource types (Computing, File System, and Archiver).

*2: Fraction of Usage：Percentage of usage relative to each resource used in one year.

ISV Software Licenses Used

ISV Software Licenses Resources
	ISV Software Licenses Used (Hours)	Fraction of Usage*2(%)
ISV Software Licenses (Total)	0.00	0.00

*2: Fraction of Usage：Percentage of usage relative to each resource used in one year.