Extreme Mechanics Letters最新文献

{"title":"A deep learning model to extract the interphase’s characteristics in microstructures using macroscopic responses","authors":"Mohammadreza Mohammadnejad,&nbsp;Majid Safarabadi,&nbsp;Mojtaba Haghighi-Yazdi","doi":"10.1016/j.eml.2024.102203","DOIUrl":"10.1016/j.eml.2024.102203","url":null,"abstract":"<div><p>This study addresses the challenge of directly measuring the mechanical and geometrical properties of the interphase region in multiphase microstructures due to its small volume. Despite the limited volume, the interphase’s properties can dramatically affect the macroscopic responses, such as elastic modulus in two directions and Poisson’s ratio, because it connects the main parts together. This work proposes a hybrid fusion deep learning model capable of accurately extracting interphase properties, including elastic modulus, Poisson’s ratio, and thickness, using both the microstructural arrangement image and the macroscopic responses of the microstructure as its inputs. To provide the required dataset, 2500 microstructures are generated using the Random Sequential Expansion (RSE) algorithm. Following microstructure generation, homogenization is applied, deriving the effective longitudinal elastic modulus and major Poisson’s ratio through the Rule of Mixture (ROM) method, complemented by the effective transverse elastic modulus obtained from numerical Finite Element (FE) modeling. The hybrid fusion model is trained using 80 % of the dataset, with the remaining instances used for model performance assessment. The R-squared value of 0.94 for the testing dataset demonstrates the model’s high accuracy in predicting interphase characteristics. The proposed model is prooved to be a solid tool for extracting the interphase properties with much less computational costs and time consumption of optimization algorithms and experiments such as atomic force microscopy and nanoindentation.</p></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"71 ","pages":"Article 102203"},"PeriodicalIF":4.3,"publicationDate":"2024-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141630315","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}

{"title":"Transition waves in bistable systems generated by collision of moving breathers","authors":"A. Paliovaios ,&nbsp;G. Theocharis ,&nbsp;V. Achilleos ,&nbsp;V. Tournat","doi":"10.1016/j.eml.2024.102199","DOIUrl":"10.1016/j.eml.2024.102199","url":null,"abstract":"<div><p>Mechanical metamaterials with multistability can support transition waves, propagation fronts that change the state of the material as they progress, and thus confer reconfigurability. The next step is to control where and when the transition wave is triggered. In this work, motivated by the existence of discrete breathers in Klein–Gordon lattices, we demonstrate that colliding moving breathers are able to trigger transition waves in bistable mechanical systems. We numerically generate counter-propagating breathers using drivers located at both ends of a finite bistable lattice, and when they collide, transition fronts can be formed. Our study reveals that fine-tuning the generated breathers allows us to control where the transition front forms in the system, and enables complex collision and transition wave triggering scenarios. The parameters of the system considered have been chosen according to experimental works on bistable lattice models under the presence of an asymmetric bistable on-site potential. Consequently, the method we propose for the remote generation of transition waves offers a new way of finely controlling the reconfiguration of mechanical systems with multiple equilibrium states.</p></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"71 ","pages":"Article 102199"},"PeriodicalIF":4.3,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141623485","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}

{"title":"Kirigami sheets in fluid flow","authors":"A.G. Carleton,&nbsp;Y. Modarres-Sadeghi","doi":"10.1016/j.eml.2024.102198","DOIUrl":"10.1016/j.eml.2024.102198","url":null,"abstract":"<div><p>Kirigami patterned materials have found several applications in recent years due to their ability to assume complicated shapes and exhibit emergent physical properties when exposed to external forces. Consisting of an array of cuts in a thin material, fabrication of these patterns can be quite simple. Here we show that when they are placed in fluid flow, kirigami cut sheets with various patterns produce a variety of flow patterns in the wake. Through several sets of experiments, we show that kirigami sheets placed in flow can undergo static or dynamic flow-induced instabilities as a result of which they can buckle or undergo limit cycle oscillations, or they can remain stable while undergoing very large elongations. These structural responses produce several different types of fluid patterns in the wake. We show that vortices both at small scales (scales comparable with the size of the individual kirigami cuts) and large scale (scales comparable with the size of the sheet) are formed in the wake of kirigami sheets. We also show that jets of different sizes can be formed and directed passively using kirigami sheets. These results show the potential of kirigami sheets for passive flow control.</p></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"71 ","pages":"Article 102198"},"PeriodicalIF":4.3,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141736586","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}

{"title":"The geometry and mechanics of the Chinese finger trap","authors":"Dingjie Lu ,&nbsp;Zhong You ,&nbsp;Zhuangjian Liu ,&nbsp;Guoxing Lu","doi":"10.1016/j.eml.2024.102200","DOIUrl":"10.1016/j.eml.2024.102200","url":null,"abstract":"<div><p>We investigate the kinematics and mechanical mechanisms of cylindrically woven straps with a plain twill pattern, which form a tubular structure known as the Chinese Finger Trap. Our findings, derived from a combination of analytical, experimental, and numerical methods, demonstrate that when subjected to axial tension, the straps within the structure undergo reconfiguration, resulting in radial contraction. The geometry of the straps influences this contraction. As the structure compacts, the linear axial force transforms into an exponential force, resulting in a catenary-like profile in woven tubes due to the axially symmetric distribution of straps. Our study of this tension-induced contraction strategy proposes a straightforward approach to manufacturing morphable structures capable of efficiently converting axial elongation into radial contraction. This technique holds potential for medical, architecture, and soft robotics applications, offering accessible and controlled engagement and disengagement capabilities.</p></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"71 ","pages":"Article 102200"},"PeriodicalIF":4.3,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141638033","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}

{"title":"High-stiffness reconfigurable surfaces based on bistable element assembly and bi-compatible truss attachment","authors":"Peidong Zhang ,&nbsp;Tong Zhou ,&nbsp;Kuan Zhang ,&nbsp;Yifei Luo ,&nbsp;Yang Li","doi":"10.1016/j.eml.2024.102187","DOIUrl":"10.1016/j.eml.2024.102187","url":null,"abstract":"<div><p>Reconfigurable surfaces contribute to multi-task robotic platforms, such as reconfigurable phased array antennas with variable aperture, by morphing between multiple specified shapes. Controlling each tile to approximate the variating shape of target surfaces requires a large number of accurate actuators. Previous research has demonstrated employing bistable-element-assembly to form reconfigurable surfaces for significant actuation simplification but suffering from low out-of-plane stiffness resulting in the lack of load-bearing capacity for carrying functional units with good mechanical accuracy. This paper proposes a design framework for tile-assembling bistable (TAB) surfaces with bi-compatible truss attachment for two prescribable stable configurations. The bistability comes from joining surface tiles with bistable elements, which contributes to easy actuation with fewer inaccurate actuators. Bi-compatible truss structures, which are only kinematically compatible at the two prescribed states, are introduced to enhance the out-of-plane stiffness of the TAB surface and improve its load-bearing capacity. Additionally and consequently, the kinematic determinacy of the reconfigurable surfaces is increased by the truss introduction, where bistable elements control the metric while truss structures dictate the principal curvature of the surface. This diminishes the redundant degrees of freedom with enhanced shape-approximation and reconfiguration-coordination. Four prototypes are designed and manufactured, which are a three-tile by three-tile (3 × 3) TAB surface that is stable at flat and spherical configurations, a 5 × 5 TAB surface with flat and spherical stable configurations, a 3 × 3 TAB surface that is stable at the flat and saddle configurations, and a 3 × 3 TAB surface that is stable at the sphere and saddle shapes. The out-of-plane stiffness, easiness of actuation, and shape accuracy of all prototypes are evaluated and show promises for real engineering applications.</p></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"71 ","pages":"Article 102187"},"PeriodicalIF":4.3,"publicationDate":"2024-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141638904","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}

{"title":"Inverse design of growth-inspired irregular architected materials for programmable properties","authors":"YuHeng Zhou ,&nbsp;YaoFu Zheng ,&nbsp;YiQi Zhang ,&nbsp;HengAn Wu ,&nbsp;Chuang Liu","doi":"10.1016/j.eml.2024.102196","DOIUrl":"https://doi.org/10.1016/j.eml.2024.102196","url":null,"abstract":"<div><p>Biomimetic metamaterials have gained increasing attention due to their exceptional characteristics such as high toughness, robust strength, and effective noise reduction. However, their complex and irregular nature presents challenges in tailoring their mechanical properties for specific applications. This study proposes a novel dual-network approach to overcome these challenges. The approach involves creating a forward model to accurately predict the mechanical properties and interconnectivity of the metamaterial without the need for growth and homogenization processes. Additionally, an inverse model is utilized to accurately predict designs for desired anisotropic stiffness. Compared to traditional bidirectional networks, our approach demonstrates superior accuracy in designing elastic properties. Our results also show that the metamaterial exhibits a broad low-frequency response while maintaining exceptional load-carrying capacity, making it a promising solution for designing low-frequency vibration suppression metamaterials.</p></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"70 ","pages":"Article 102196"},"PeriodicalIF":4.3,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141594425","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}

{"title":"How crack twisting in bouligand structures lead to damage delocalization and toughening","authors":"Alvaro Garnica ,&nbsp;Emiliano Aparicio ,&nbsp;Mehdi Shishehbor ,&nbsp;David Kisailus ,&nbsp;Eduardo M. Bringa ,&nbsp;Pablo D. Zavattieri","doi":"10.1016/j.eml.2024.102190","DOIUrl":"https://doi.org/10.1016/j.eml.2024.102190","url":null,"abstract":"<div><p>Fiber-reinforced composites with Bouligand structure exhibit remarkable mechanical properties due to the intricate arrangement of fibers. In this study, we propose a coarse-graining (CG) model specifically developed to capture the behavior of Bouligand structures. The model incorporates bonded interactions to represent the fibers and employs a double-well potential to describe the non-bonded interactions within the matrix. Using this model, we investigate the fracture mechanics properties of Bouligand structures, with a particular focus on the emergence of helicoidal cracks. Our primary objective is to validate the hypothesis that these twisting cracks, which align with the fiber orientation, contribute to local hardening mechanisms. By hindering the growth of individual cracks, these hardening mechanisms facilitate the nucleation and growth of multiple cracks, thereby promoting a delocalization effect within the material. Through extensive simulations and analysis, we confirm the validity of our hypothesis. The presence of twisting cracks indeed induces local hardening mechanisms, making it more challenging for individual cracks to propagate. This phenomenon effectively spreads the damage, dissipating energy across larger volumes of the material. Consequently, the toughness of these Bouligand structures is enhanced, as this delocalization effect effectively mitigates the concentration of damage. These findings provide valuable insights into the fracture behavior of Bouligand structures and shed light into the underlying mechanisms responsible for their exceptional mechanical performance. Moreover, our CG model offers a practical and efficient approach to studying and understanding the fracture mechanics properties of complex fiber-reinforced composites. The ability to simulate and analyze the behavior of helicoidal cracks within Bouligand structures opens up new avenues for designing and optimizing advanced materials with enhanced toughness and damage resistance.</p></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"71 ","pages":"Article 102190"},"PeriodicalIF":4.3,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141604934","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}

{"title":"Effect of aspect ratio and axial tensile load on the inflation of cylindrical tubes","authors":"Jinwoo Lee,&nbsp;Byungho Lee,&nbsp;Anna Lee","doi":"10.1016/j.eml.2024.102189","DOIUrl":"https://doi.org/10.1016/j.eml.2024.102189","url":null,"abstract":"<div><p>We explore the snap-through instability in hyper-elastic cylindrical tubes during inflation, specifically investigating the influences of geometry and imposed axial tensile loads on both the bulging shape profiles and the initiation pressure of the bulge. We perform bulging experiments on latex rubber tubes with different parameters such as the length-to-diameter aspect ratio and axial tension. To complement these experiments, finite element simulations across various geometries and a theoretical analysis of an infinite-length tube are conducted. Our simulations reveal a critical aspect ratio that divides the bulging into two possibilities: short tubes exhibit whole bulging, while longer tubes show localized bulging. Both experimental and simulation findings indicate that as the aspect ratio and axial tensile load increase, the initiation pressure diminishes and then converges. Notably, when the axial tensile load surpasses the shear modulus, it obstructs snap-through in shorter tubes and neutralizes the influence of the aspect ratio on the initiation pressure. The outcomes of this research offer valuable perspectives on modulating the bulging mode and initiation pressure in tubular structures within soft devices, including soft pneumatic actuators and energy harvesters.</p></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"71 ","pages":"Article 102189"},"PeriodicalIF":4.3,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141604932","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}

{"title":"Interfacial fracture of Perovskite Light Emitting Devices","authors":"J. Cromwell ,&nbsp;R. Ichwani ,&nbsp;O.K. Oyewole ,&nbsp;J. Adjah ,&nbsp;W.O. Soboyejo","doi":"10.1016/j.eml.2024.102201","DOIUrl":"https://doi.org/10.1016/j.eml.2024.102201","url":null,"abstract":"<div><p>This paper presents the results of an interfacial fracture study of Perovskite Light Emitting Devices (PLEDs). The interfacial robustness of the interfaces between the active layer and the adjacent layers of PLEDs is explored in an effort to simulate the effects of applied loads on pre-existing defects that are present in PLEDs. The dependence of interfacial fracture toughness on mode mixity (ratio of mode I and mode II) was studied using Brazil disk testing. The crack microstructure interactions associated with crack growth were then studied along with the underlying fracture modes and toughening mechanisms. The underlying toughening mechanisms were then modeled before discussing the implications of the current work for the design of mechanically robust PLEDs.</p></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"71 ","pages":"Article 102201"},"PeriodicalIF":4.3,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141604929","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}

{"title":"Curvy cuts: Programming axisymmetric kirigami shapes","authors":"Marie Tani ,&nbsp;Joo-Won Hong ,&nbsp;Takako Tomizawa ,&nbsp;Étienne Lepoivre ,&nbsp;José Bico ,&nbsp;Benoît Roman","doi":"10.1016/j.eml.2024.102195","DOIUrl":"https://doi.org/10.1016/j.eml.2024.102195","url":null,"abstract":"<div><p>Although bending a sheet of paper is an easy operation, stretching is more limited and it leads to rupture and tears. However, well-designed cuts on the sheet can induce a large effective stretchability. This kirigami technique offers a large scope of engineering applications ranging from deployable structures to compliant electronics. We are here interested in the axisymmetric configuration where cuts are designed along concentric circles. Applying an increasing transverse load at the center of the sheet results into a 3D axisymmetric structure of growing amplitude which eventually saturates. We first describe the linear response of the structure and determine the evolution of the deployed shape until its asymptotic geometrical limit. Reversing the problem in the linear regime, we propose, a design procedure for the cuts leading to a desired 3D shape. The structure can also be deployed by inflating an inner balloon. Exploring further the interplay between mechanics and geometry, we finally describe the maximum volume of inflated kirigami structures as a function of the cutting pattern.</p></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"71 ","pages":"Article 102195"},"PeriodicalIF":4.3,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141604931","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}