Extreme Mechanics Letters最新文献_第4页

A non-iterative numerical approach for visco-elasto-hydrodynamic lubrication problems

IF 4.3 3区工程技术

Extreme Mechanics Letters Pub Date : 2025-01-01 DOI: 10.1016/j.eml.2024.102278

Ashwin Sahasranaman , Chung Yuen Hui

{"title":"A non-iterative numerical approach for visco-elasto-hydrodynamic lubrication problems","authors":"Ashwin Sahasranaman , Chung Yuen Hui","doi":"10.1016/j.eml.2024.102278","DOIUrl":"10.1016/j.eml.2024.102278","url":null,"abstract":"<div><div>In lubrication applications, a common scenario involves a hard solid in contact with a soft viscoelastic substrate. However, most of the existing literature focuses on the case of an elastic substrate. In this paper, we introduce a numerical method that overcomes the challenges of converging iterative techniques and is specifically designed to handle viscoelastic substrates described by a Prony series. Our approach is fully automated, stable, and efficient, requiring only the solution of a linear matrix equation at each time step. We apply this method to investigate the transient squeezing of a thin liquid film between a rigid spherical indenter and a soft viscoelastic substrate. We explore intriguing differences between the EHL (Elasto-hydrodynamic lubrication) problem and three viscoelastic substrates with single and multiple relaxation times to understand how temporally evolving stiffness affects the pressure, surface displacement, and liquid film thickness. One of the key differences between the EHL and the VEHL (Visco-elasto-hydrodynamic lubrication) problem comes to light upon looking at the entrapped volume which can be held nearly constant when using a viscoelastic substrate whereas elastic substrates show exponential decay.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"74 ","pages":"Article 102278"},"PeriodicalIF":4.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143143137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Do slip-weakening laws shapes influence rupture dynamics?

IF 4.3 3区工程技术

Extreme Mechanics Letters Pub Date : 2025-01-01 DOI: 10.1016/j.eml.2024.102272

Roxane Ferry, Jean-François Molinari

{"title":"Do slip-weakening laws shapes influence rupture dynamics?","authors":"Roxane Ferry, Jean-François Molinari","doi":"10.1016/j.eml.2024.102272","DOIUrl":"10.1016/j.eml.2024.102272","url":null,"abstract":"<div><div>To model rupture dynamics, a friction law must be assumed. Commonly used constitutive laws include slip-weakening laws which are characterized by a drop from static to dynamic frictional stress over a critical slip distance. Within this framework, the prevailing understanding asserts that the frictional behavior is solely controlled by the fracture energy — the area beneath the frictional stress versus the cumulative slip curve. In particular, it is claimed that the curve’s shape itself has no influence on the system’s response. Here we perform fully dynamic rupture simulations to challenge prevailing beliefs by demonstrating that the constitutive law shape exerts an intimate control over rupture dynamics. These results are confirmed using two independent numerical schemes (spectral boundary integral and finite element methods). For a consistent fracture energy but varying constitutive weakening law shapes, the slip velocity profile is different: each abrupt slope transition leads to the localization of a distinct velocity peak. For example, in the case of a bilinear slip-weakening law featuring two different slopes, the rupture exhibits two distinct velocity peaks. This phenomenon arises from the transition between a constant weakening rate to another. We show that ruptures with the same fracture energy but different constitutive law shapes may respond differently to stress barriers, especially when cumulative slip is below the critical slip <span><math><msub><mrow><mi>D</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span>. In these cases, variations in effective fracture energy across different laws lead to differing outcomes: under one law, a rupture may propagate past a barrier, while under another, it may arrest. These findings underscore the critical role of constitutive law shape on rupture dynamics, influencing the response to small-scale asperities and heterogeneities and to larger-scale barriers, and highlighting the importance of both fracture energy and weakening mechanisms for seismic hazard assessment.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"74 ","pages":"Article 102272"},"PeriodicalIF":4.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143142520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Machine learning-aided prediction and customization on mechanical response and wave attenuation of multifunctional kiri/origami metamaterials

IF 4.3 3区工程技术

Extreme Mechanics Letters Pub Date : 2025-01-01 DOI: 10.1016/j.eml.2024.102276

Sihao Han, Chunlei Li, Qiang Han, Xiaohu Yao

{"title":"Machine learning-aided prediction and customization on mechanical response and wave attenuation of multifunctional kiri/origami metamaterials","authors":"Sihao Han, Chunlei Li, Qiang Han, Xiaohu Yao","doi":"10.1016/j.eml.2024.102276","DOIUrl":"10.1016/j.eml.2024.102276","url":null,"abstract":"<div><div>Multifunctional materials attract extensive attention for simultaneously satisfying diverse engineering applications, such as protection against mechanical and vibratory intrusions. Here, the mechanical responses and wave attenuation of multi-functional metamaterials at various elastoplastic are custom-designed. An elegant kiri/origami metamaterial is proposed, offering widely tunable mechanical responses and broadband wave attenuation in ultra low-frequencies. The incomparable compression-twist of kresling origami and the prominent local-resonance of kirigami split-rings promote efficient elastic wave polarization and plastic hinges, providing comprehensive protection from elastic to plastic. Kirigami split-rings highlight a fabrication-friendly approach of forming local resonators. Experiments and analyses confirm the reliability and superiority. Leveraging a machine learning-aided framework, optimal and anticipated individual properties and custom multi-performances are achieved for wave attenuation, energy absorption, plateau fluctuations, deformation triggering forces, and load-bearing/plateau forces under various impact levels. The machine learning-aided framework enables rapid multi-objective prediction and customization end-to-end without requiring prior knowledge. This work holds significant potential for the development and application of multi-functional, multi-physical field and multi-scale metamaterials.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"74 ","pages":"Article 102276"},"PeriodicalIF":4.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143143131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Crystal size effect on large deformation mechanisms of thermoplastic polyurethane

IF 4.3 3区工程技术

Extreme Mechanics Letters Pub Date : 2025-01-01 DOI: 10.1016/j.eml.2024.102275

Zhaoxin Zhang, Shuze Zhu

{"title":"Crystal size effect on large deformation mechanisms of thermoplastic polyurethane","authors":"Zhaoxin Zhang, Shuze Zhu","doi":"10.1016/j.eml.2024.102275","DOIUrl":"10.1016/j.eml.2024.102275","url":null,"abstract":"<div><div>Thermoplastic polyurethane, a phase-separated polymer containing amorphous soft domains and crystal hard domains, is a widely used high-performance polymer. However, how the crystal size affects the mechanical properties of thermoplastic polyurethane remains unclear. In this work, molecular dynamics simulations are carried out to reveal the atomistic deformation mechanisms coupled to crystal sizes. The atomistic models contain finite crystal hard domains in a representative volume element with periodicity in three dimensions. With comprehensive analysis in tension, compression, and shear, we find that the crystal size affects the timing and difficulty of deconstruction and rotation in crystal hard domain, cavitation in amorphous soft domain, and therefore determine the structural strength at different deformation stages. For example, smaller crystal size renders higher yield strength yet lower ultimate tensile strength. The discovered crystal size effect allows us to envision a gradient nano-crystal thermoplastic polyurethane with its customizable yet exceptional mechanical properties. By engineering the spatial distribution of crystals with different sizes, the gradient nano-crystal thermoplastic polyurethane can be strong in tension, yet soft in compression. Our current work deepens the understanding of the deformation mechanisms of thermoplastic polyurethanes and provides insights into the rational design of block copolymer materials with desirable mechanical properties.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"74 ","pages":"Article 102275"},"PeriodicalIF":4.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143143134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Characterization of 3D printed micro-blades for cutting tissue-embedding material

IF 4.3 3区工程技术

Extreme Mechanics Letters Pub Date : 2025-01-01 DOI: 10.1016/j.eml.2024.102288

Saisneha Koppaka, David Doan, Wei Cai, X. Wendy Gu, Sindy K.Y. Tang

{"title":"Characterization of 3D printed micro-blades for cutting tissue-embedding material","authors":"Saisneha Koppaka, David Doan, Wei Cai, X. Wendy Gu, Sindy K.Y. Tang","doi":"10.1016/j.eml.2024.102288","DOIUrl":"10.1016/j.eml.2024.102288","url":null,"abstract":"<div><div>Cutting soft materials on the microscale has emerging applications in single-cell studies, tissue microdissection for organoid culture, drug screens, and other analyses. However, the cutting process is complex and remains incompletely understood. Furthermore, precise control over blade geometries, such as the blade tip radius, has been difficult to achieve. In this work, we use the Nanoscribe 3D printer to precisely fabricate micro-blades (i.e., blades <1 mm in length) and blade grid geometries. This fabrication method enables a systematic study of the effect of blade geometry on the indentation cutting of paraffin wax, a common tissue-embedding material. First, we print straight micro-blades with tip radius ranging from ∼100 nm to 10 μm. The micro-blades are mounted in a custom nanoindentation setup to measure the cutting energy during indentation cutting of paraffin. Cutting energy, measured as the difference in dissipated energy between the first and second loading cycles, decreases as blade tip radius decreases, until ∼357 nm when the cutting energy plateaus despite further decrease in tip radius. Second, we expand our method to blades printed in unconventional configurations, including parallel blade structures and blades arranged in a square grid. Under the conditions tested, the cutting energy scales approximately linearly with the total length of the blades comprising the blade structure. The experimental platform described can be extended to investigate other blade geometries and guide the design of microscale cutting of soft materials.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"75 ","pages":"Article 102288"},"PeriodicalIF":4.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143048804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

High bulk modulus pentamodes: the three-dimensional metal water

IF 4.3 3区工程技术

Extreme Mechanics Letters Pub Date : 2025-01-01 DOI: 10.1016/j.eml.2024.102267

Giacomo Brambilla, Sebastiano Cominelli, Marco Verbicaro, Gabriele Cazzulani, Francesco Braghin

{"title":"High bulk modulus pentamodes: the three-dimensional metal water","authors":"Giacomo Brambilla, Sebastiano Cominelli, Marco Verbicaro, Gabriele Cazzulani, Francesco Braghin","doi":"10.1016/j.eml.2024.102267","DOIUrl":"10.1016/j.eml.2024.102267","url":null,"abstract":"<div><div>Despite significant advances in the field of phononic crystals, the development of acoustic metafluids that replicate the behaviour of liquids in three dimensions remains elusive. For instance, water – the quintessential pentamode (PM) material – has a bulk modulus two orders of magnitude higher than current state-of-the-art PMs. The need for a low shear modulus inherently conflicts with the desire of high bulk modulus and density. In this letter, we shed light on the limitations of existing PM geometries and propose an innovative shape for the links that constitute the network. Inspired by the kinematics of ropes, these links are constructed from thin fibres and demonstrate the potential to create PMs with properties akin to those of liquids. As a prime example, we propose the design of the first metamaterial that fully deserves the name <em>3D metal water</em>, since its acoustic properties in the low frequency regime are indistinguishable from water. Additionally, we highlight a shear band gap in the lattice dispersion diagram, and illustrate the influence of geometric parameters on the dynamic properties at higher frequencies. This novel design of metafluids holds promise for applications requiring anisotropic materials such as acoustic lenses, waveguides, and cloaks.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"74 ","pages":"Article 102267"},"PeriodicalIF":4.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143142518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Micropolar modeling for bending shape of 2D lattices: The case of equilateral triangular cell structure

IF 4.3 3区工程技术

Extreme Mechanics Letters Pub Date : 2025-01-01 DOI: 10.1016/j.eml.2024.102281

L.H. He, C.Y. Shen

引用次数: 0

Energy dissipation mechanism of G-phase and L-phase metallic glass nanofilms subjected to high-velocity nano-ballistic impact

IF 4.3 3区工程技术

Extreme Mechanics Letters Pub Date : 2025-01-01 DOI: 10.1016/j.eml.2024.102280

Yujie Cheng , Yidi Shen , Qi An , Minqiang Jiang , Chenguang Huang , William A. Goddard III , Xianqian Wu

{"title":"Energy dissipation mechanism of G-phase and L-phase metallic glass nanofilms subjected to high-velocity nano-ballistic impact","authors":"Yujie Cheng , Yidi Shen , Qi An , Minqiang Jiang , Chenguang Huang , William A. Goddard III , Xianqian Wu","doi":"10.1016/j.eml.2024.102280","DOIUrl":"10.1016/j.eml.2024.102280","url":null,"abstract":"<div><div>The energy dissipation mechanisms of G-phase and L-phase metallic glass nanofilms subjected to high-velocity nano-particle impact were investigated by molecular dynamics (MD) simulations. We identified the phase transition from G-phase to L-phase in which the locally ordered core structures transform to liquid-like structures due to local mechanical melting and adiabatic heating of the G-phase under high strain rate impact. The appearance of phase transition provides a new channel for energy dissipation, thus the relatively thicker G-phase nanofilm with ordered core structures has a higher specific energy absorption compared with the L-phase film at the same thickness and impact velocity. However, if the thickness decreases below the characteristic length scale of the heterogeneous structure, the broken core structures in the G-phase films act as prefabricated defects that fail prematurely when subjected to impact, resulting in less impact resistance of the G-phase film compared to the L-phase film. This paper provides a useful method for improving the impact resistance of metallic glass films by tailoring the microstructures.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"74 ","pages":"Article 102280"},"PeriodicalIF":4.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143142519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Tailoring cell geometry and assembly of modular origami tube for programmable biaxial response under static and impact loads

IF 4.3 3区工程技术

Extreme Mechanics Letters Pub Date : 2025-01-01 DOI: 10.1016/j.eml.2024.102283

Lu Zhu , Yangsheng Lin , Ruiqi Ma , Jiachen Li , Meishan Yin , Yunquan Li , Dongdong Zhao , Nan Hu

{"title":"Tailoring cell geometry and assembly of modular origami tube for programmable biaxial response under static and impact loads","authors":"Lu Zhu , Yangsheng Lin , Ruiqi Ma , Jiachen Li , Meishan Yin , Yunquan Li , Dongdong Zhao , Nan Hu","doi":"10.1016/j.eml.2024.102283","DOIUrl":"10.1016/j.eml.2024.102283","url":null,"abstract":"<div><div>Origami-based architected materials (OAMs) has shown great potential as a rich source to create reconfigurable structures for various applications. However, most existing OAMs are designed for one specific properties in a single direction without considering their global anisotropic mechanical properties. Herein, we propose a novel structural design and assembly strategy of modular origami tube (MOT) with incredibly programmable anisotropic characteristics, aiming to achieve on-demand biaxial response, foldability, and versatility simultaneously along different loading directions. Guided by numerical simulations and experimental tests, we showcase the tunability of biaxial response in MOT units by varying cell geometry and hinge thickness under quasi-static compression. When loaded in the vertical direction, MOT unit exhibits high stiffness and achieves almost 8.3 times peak force value higher than the corresponding data in the lateral direction. It has also been proved that this distinction can be controlled to become smaller or larger by adjusting stiffnesses at vertical and lateral hinges. After strategically assembling various MOT cell units, we developed OAMs structures whose biaxial response can achieve high re-programmability under different impact loading directions, enriching the versatility of such new structural units in designing OAMs structures for multifunctional structural applications.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"74 ","pages":"Article 102283"},"PeriodicalIF":4.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143143135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Fresh considerations regarding time-dependent elastomeric fracture

IF 4.3 3区工程技术

Extreme Mechanics Letters Pub Date : 2025-01-01 DOI: 10.1016/j.eml.2024.102277

Shi-Qing Wang, Zehao Fan , Asal Siavoshani , Ming-chi Wang, Junpeng Wang

{"title":"Fresh considerations regarding time-dependent elastomeric fracture","authors":"Shi-Qing Wang, Zehao Fan , Asal Siavoshani , Ming-chi Wang, Junpeng Wang","doi":"10.1016/j.eml.2024.102277","DOIUrl":"10.1016/j.eml.2024.102277","url":null,"abstract":"<div><div>The fracture behavior of polymers in elastomeric state exhibits rich characteristics. Stretch rate and temperature can independently, as well as in combination, influence how such polymeric networks resist crack initiation and propagation. The strong rate and temperature dependencies of tensile strength and toughness in absence of high viscoelasticity, previously shown to occur in Rubber Chem&Tech <strong>96</strong>, 530, 2023 and plausibly in J. Polym. Sci. <strong>18</strong>, 189, 1955 and <strong>32</strong>, 99, 1958 are also observed in rate-sensitive elastomers. This work aims to propose, at a conceptual level, a general understanding of elastomeric fracture by addressing the considerable confusion surrounding the relationship between crack growth rate (v<sub>c</sub>) and Griffth-Irwin's energy release rate (G<sub>c</sub>) in different elastomeric systems. Our fracture tests demonstrate that (a) crack propagation velocity <em>v</em><sub>c</sub> varies with the applied loading level produced by either stepwise or continuous stretching, (b) emergent entanglement effectively modifies network structure and the relationship between <em>v</em><sub>c</sub> and G<sub>c</sub>, and (c) temperature T affects <em>v</em><sub>c</sub> at a given load. We conclude that the magnitude of imposed strain, from which G<sub>c</sub> may be evaluated, prescribes the level of bond tension in load-bearing network strands and dictates bond dissociation kinetics. Consequently, crack growth rate depends explicitly on loading level (e.g., G<sub>c</sub>) and temperature. In the relationship between v<sub>c</sub> and G<sub>c</sub>, v<sub>c</sub> is the effect and G<sub>c</sub> is the cause, contrary to the previous viewpoint.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"74 ","pages":"Article 102277"},"PeriodicalIF":4.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143143136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0