Zhi Sheng, Jie Ma, Zihang Shen, Shaoxing Qu, and Zheng Jia*, Chemomechanics Underpinning the Growth and Strengthening Behaviors of Mechanoresponsive Self-Growing Hydrogels, Macromolecules (2023)
Abstract
Background: Helmet systems most commonly experience oblique blunt impacts which cause simultaneous linear and rotational accelerations. The ability to attenuate both linear and rotational accelerations by absorbing the normal shock while accommodating large shear deformations with energy dissipation is critical to developing superior helmet liners that prevent traumatic brain injury (TBI).
On November 2023 the research unit MUSAM -Multi-scale Analysis of Materials- at the IMT School for Advanced Studies Lucca turns 10!
To celebrate the contributions made to computational and experimental mechanics over the past 10 years, and to acknowledge the PhD students, researchers and visiting professors that have animated the research unit, I am pleased to share with you a 10-year impact report.
I hope you might find it interesting and inspiring for future collaborations!
cdmHUB invites you to attend the Global Composites Experts Webinar Series.
Title: US-COMP: Next Generation of Composites Materials for Crewed Deep Space Missions
Speaker: Dr. Gregory M. Odegard, Michigan Technological University
Time: 12/14, 11AM-12PM EST.
Register in advance for this webinar: https://bit.ly/3uy3zpg.
Ernest Rabinowicz’s words, spoken two decades ago in his groundbreaking textbook on the friction and wear of materials [1], continue to resonate today: ’Although wear is an important topic, it has never received the attention it deserves.’ Rabinowicz’s work laid the foundation for contemporary tribology research [2]. Wear, characterized as the removal and deformation of material on a surface due to the mechanical action of another surface, carries significant consequences for the economy, sustainability, and poses health hazards through the emission of small particles. According to some estimates [1, 3], the economic impact is substantial, accounting for approximately 5% of the Gross National Product (GNP).
Despite its paramount importance, scientists and engineers often shy away from wear analysis due to the intricate nature of the underlying processes. Wear is often perceived as a ”dirty” topic, and with good reason. It manifests in various forms, each with its own intricacies, arising from complex chemical and physical processes. These processes unfold at different stages, creating a time-dependent phenomenon influenced by key parameters such as sliding velocity, ambient or local temperature, mechanical loads, and chemical reactions in the presence of foreign atoms or humidity.
The review paper by Vakis et al. [5] provides a broad perspective on the complexity of tribology problems. This complexity has led to numerous isolated studies focusing on specific wear mechanisms or processes. The proliferation of empirical wear models in engineering has resulted in an abundance of model variables and fit coefficients [6], attempting to capture the intricacies of experimental data.
Tribology faces a fundamental challenge due to the multitude of interconnected scales. Surfaces exhibit roughness with asperities occurring at various wavelengths. Only a small fraction of these asperities come into contact, and an even smaller fraction produces wear debris. The reasons behind why, how, and when this occurs are not fully understood. The debris gradually alter the surface profile and interacts with one another, either being evacuated from the contact interface or gripping it, leading to severe wear. Due to this challenge of scales, contributions of numerical studies in wear research over the past decades sum up to less than 1% (see Fig. 1). Yet, exciting opportunities exist for modeling, which we attempt to discuss here.
While analyzing a single asperity contact may not unveil the entire story, it arguably represents the most fundamental level to comprehend wear processes. This blog entry seeks to encapsulate the authors’ perspective on this rapidly evolving topic. Acknowledging its inherent bias, the aim is to spark controversies and discussions that contribute to a vibrant blogosphere on the mechanics of the process.
The subsequent section delves into the authors’ endeavors in modeling adhesive wear at the asperity level. Section 3 navigates the transition to abrasive wear, while Section 4 explores opportunities for upscaling asperity-level mechanisms to the meso-scale, with the aspiration of constructing predictive models. Lastly, although the primary focus of this blog entry is on modeling efforts, it would be remiss not to mention a few recent advances on the experimental front.
EML Webinar (Young Researchers Forum) on 28 November 2023 will be given by Diego Misseroni at University of Trento via Zoom meeting
Title: Reprogrammable Frustration, Multistability, and Tunable Auxeticity in Origami Metamaterials
Discussion leader: Glaucio Paulino, Princeton University
Time: 9:30 am Boston, 2:30 pm London, 3:30 pm Paris, 10:30 pm Beijing on Tuesday, 28 November 2023
Extreme Mechanics Letters is pleased to announce the Recipients of the 2023 EML Young Investigator Award
Dear Colleagues,
Please see our recent article on toughening 3D printable resins with block copolymer additives:
Extreme Mechanics Letters (EML) Special Issue: Call for Paper
Machine Learning and Mechanics
Over the past decade, there has been a growing interest in applying machine learning techniques to problems in mechanics. From material design optimization, manufacturing, to multiscale modelling, to real time prediction and autonomy, data mining and analysis, machine learning techniques have had a massive impact in the field.
