Preface for MMM 2018 focus issue

This focus issue contains the selected papers presented in the 9th Multiscale Materials Modeling Conference (MMM 2018), which was held in Osaka, Japan, from 28 October to 2 November 2018.

In the last 20 years, Multiscale Materials Modeling (MMM) has dramatically grown and become a principal pillar of materials science and engineering through the eight landmark MMM meetings. The main theme of this MMM2018 in Osaka was 'Toward the next twenty years, opening new era in Multiscale Materials Modeling'. The scientific program consisted of 6 plenary presentations delivered by worldwide leading speakers and 15 symposia comprising 135 invited talks, 418 oral and 157 poster presentations. These symposia involved a characteristic one unique to Japan, which raised the bridging between fracture and earthquake. This focus issue reflects many of the themes of these symposia shown in the following:

• (A)  
  Advances in Materials Theory for Multiscale Modeling
• (B)  
  Challenges in the Multiscale Modeling of Radiation Effects in Nuclear Materials
• (C)  
  Crystal Plasticity: From Electrons to Dislocation Microstructure
• (D)  
  Data-Driven and Physics-Informed Materials Discovery and Design
• (E)  
  Deformation and Fracture Mechanism of Materials
• (F)  
  From Microstructure to Properties: Mechanisms, Microstructure, Manufacturing
• (G)  
  Modeling Mechanical Behavior of Materials under Harsh Environments
• (H)  
  Multiscale Mechanics of Polymers, Soft Matter and Network Materials
• (I)  
  Multiscale Modeling of Grain Boundary Dynamics, Grain Growth and Polycrystal Plasticity
• (J)  
  Multiscale Modeling of Heterogeneous Layered Media
• (K)  
  Multiscale Simulations of Catastrophic Phenomena: Toward Bridging between Materials Fracture and Earthquake
• (L)  
  Structure, Statistics and Mechanics in Crystal Dislocation Plasticity
• (M)  
  Time- and History-Dependent Material Properties
• (N)  
  Towards Experimentally Relevant Time Scales: Methods for Extending Atomistic Simulation Times and Their Applications in Material Science
• (O)  
  Tribology and Interface: Multi-Scale, Multi-Physics, and Multi-Chemistry Phenomena in Friction, Lubrication, Wear, and Adhesion.

The MMM conference series is the world's largest theoretical and computational materials science forum, aiming to disseminate the latest developments in the field of multiscale materials modeling with applications to more complex materials involving increasingly coupled multi-physical phenomena. These attractive applications are driven by the tremendous computing power and the sophisticated mathematical algorithms.

The present focus issue contains 25 original peer-reviewed papers, which show the very broad range of scales covered by the researches presented in MMM 2018. The major contributions are related to the Phase Field method [1–10] and Molecular Dynamics simulations [11–14] with the potential generation process [15], which have resolved the large-scaled crystallization [8, 9], grain boundary migration [12], yielding of metals [16], and processing [3, 5]. These fundamental phenomena need the huge length and time-scales. Some papers report the state-of-the-art studies based on the interdisciplinary chemo-mechanics of battery problem [17]. Also, the key words of machine learning and knowledge-based system [1, 18] might be increasing in the days ahead. The coupled analysis between experimental and computational approaches is promising because the innovative laboratory setups with the extremely high resolution have been aggressively developed [19]. The new materials-related subjects are encouraged including amorphous [20], nanoparticle [21], and ceramics [22]. The defect mechanics has a long history and is still much active and attractive ongoingly [13, 16, 23–25]. These articles published in the present focus issue illustrate the academic flow in the heart of the MMM conferences.

The organizing committee of the MMM 2018 conference would like to thank all the symposium organizers, all the participants presenting their contributions to MMM 2018, the International Advisory Committee members, session chairs, and the authors of the selective papers published here. The committee also deeply thanks to The Japan Society of Mechanical Engineers (JSME), The Society of Materials Science, Japan (JSMS), The Japan Institute of Metals and Materials (JIM). The conference was sponsored by IOP Publishing, Springer Nature, Corona Publishing Co., Ltd, JSOL Corporation, Dassault Systems, High Performance Computing Technology, Real Computing, inc., ESI Japan Ltd, and the JSMS Committee on Multiscale Materials Mechanics. Finally, the committee highly appreciates the contributions of Osaka University and Kanazawa University's staff for completing an excellent conference.

Chair committee of MMM2018

Yoji Shibutani Osaka University, Japan

Shigenobu Ogata Osaka University, Japan

Tomotsugu Shimokawa Kanazawa University, Japan