Extreme Mechanics Letters最新文献_第4页

Deformation and adiabatic heating of single crystalline and nanocrystalline Ni micropillars at high strain rates 单晶和纳米晶镍微柱在高应变速率下的变形和绝热加热

IF 4.3 3区工程技术

Extreme Mechanics Letters Pub Date : 2025-04-17 DOI: 10.1016/j.eml.2025.102336

Nidhin George Mathews , Matti Lindroos , Johann Michler , Gaurav Mohanty

{"title":"Deformation and adiabatic heating of single crystalline and nanocrystalline Ni micropillars at high strain rates","authors":"Nidhin George Mathews , Matti Lindroos , Johann Michler , Gaurav Mohanty","doi":"10.1016/j.eml.2025.102336","DOIUrl":"10.1016/j.eml.2025.102336","url":null,"abstract":"<div><div>The deformation behavior of single crystal and nanocrystalline nickel were studied using <em>in situ</em> micropillar compression experiments from quasi-static to high strain rates up to 10<sup>3</sup> s<sup>−1</sup>. Deformation occurred by dislocation slip activity in single crystal nickel whereas extensive grain boundary sliding was observed in nanocrystalline nickel with a shift towards more inhomogeneous, localized deformation above 1 s<sup>−1</sup>. The strain rate sensitivity exponent was found to change at higher strain rates for both single crystal and nanocrystalline nickel, while the overall strain rate sensitivity was observed to be of the same value for both. With increasing high strain rate micropillar compression tests being reported, the issue of adiabatic heating in micropillars becomes important. We report crystal plasticity based finite element modeling to estimate the adiabatic heating, spatially resolved within the micropillar, at the highest tested strain rates. The simulations predicted a significant temperature rise of up to 200 K in nanocrystalline nickel at the grain boundaries, and 20 K in single crystalline nickel due to strain localization. Transmission Kikuchi Diffraction analysis of nanocrystalline nickel micropillar post compression at 10<sup>3</sup> s<sup>−1</sup> did not show any grain growth.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"77 ","pages":"Article 102336"},"PeriodicalIF":4.3,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143870479","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

A method for identifying the damage thresholds of porcine brain under low- and medium-strain rates 中低应变率下猪脑损伤阈值的识别方法

IF 4.3 3区工程技术

Extreme Mechanics Letters Pub Date : 2025-04-15 DOI: 10.1016/j.eml.2025.102335

Zhihui Qu , Yimou Fu , Qiuping Yang , Jingyu Wang , Liqun Tang , Shaoxing Qu

{"title":"A method for identifying the damage thresholds of porcine brain under low- and medium-strain rates","authors":"Zhihui Qu , Yimou Fu , Qiuping Yang , Jingyu Wang , Liqun Tang , Shaoxing Qu","doi":"10.1016/j.eml.2025.102335","DOIUrl":"10.1016/j.eml.2025.102335","url":null,"abstract":"<div><div>Predicting the damage thresholds of brain tissue is crucial for preventing permanent pathological changes and developing therapeutic interventions. This study presents a method for determining the damage thresholds of porcine brain tissue using experimental data and theoretical modeling. By conducting loading and unloading experiments on porcine brain samples, the mechanical responses under varying strain rates and maximum compressive strains are analyzed. A constitutive model incorporating viscoelastic behavior, the Mullins effect, and residual deformation is proposed, effectively characterizing the mechanical properties of the brain tissue. By calculating the ratio of damage-induced dissipated energy and viscoelastic dissipated energy, the extent of damage under different maximum compression strain is quantified. The method’s reliability is validated through examining changes in modulus between the stress–strain curves obtained from the first and second loadings. At a strain rate of 0.3<span><math><msup><mrow><mi>s</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math></span>, the mild damage strain threshold is estimated to be 0.2 – 0.3, while the moderate-to-severe damage threshold falls within 0.3 – 0.4, aligning closely with values reported in the literature. Additionally, the damage strain thresholds at 200<span><math><msup><mrow><mi>s</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math></span> are consistent with those at 0.3<span><math><msup><mrow><mi>s</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math></span>. The corresponding stress threshold at 200<span><math><msup><mrow><mi>s</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math></span>ranges from 5.9 to 11.4 kPa for mild damage and from 11.4 to 22.8 kPa for moderate-to-severe damage. The findings of this study are expected to contribute to brain damage prediction.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"77 ","pages":"Article 102335"},"PeriodicalIF":4.3,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143843920","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

Switchable acoustic notch filter using a 3D-printed Helmholtz resonator array with bistable structures 使用具有双稳结构的3d打印亥姆霍兹谐振器阵列的可切换声学陷波滤波器

IF 4.3 3区工程技术

Extreme Mechanics Letters Pub Date : 2025-04-12 DOI: 10.1016/j.eml.2025.102333

Masahiro Fukuta , Gakuto Kagawa , Hidetoshi Takahashi

{"title":"Switchable acoustic notch filter using a 3D-printed Helmholtz resonator array with bistable structures","authors":"Masahiro Fukuta , Gakuto Kagawa , Hidetoshi Takahashi","doi":"10.1016/j.eml.2025.102333","DOIUrl":"10.1016/j.eml.2025.102333","url":null,"abstract":"<div><div>Acoustic noise is a significant environmental issue that affects quality of life, including in workplaces. Therefore, the ability to selectively block specific sound frequencies is desired to maintain clear vocal communication. Electrically driven active noise control (ANC) is a common solution. However, its effectiveness is limited to frequencies above 1 kHz. On the other hand, passive noise control (PNC) has gained attention as an alternative solution due to its non-reliance on electricity. Among these, Helmholtz resonators (HRs) have recently attracted interest due to their ability to reduce acoustic noise at their resonant frequencies. Traditional HRs are generally limited to attenuating single frequencies, which restricts their ability to attenuate multiple frequencies using a single device. Herein, we propose an HR featuring a bistable structure that enables switching between two distinct attenuation frequencies. A bistable structure with two stable states allows for switchable configurations that enable volume changes. By integrating this bistable mechanism into an HR chamber, the resonant frequency can be altered by changing the chamber volume. Consequently, the proposed HR can attenuate two different frequencies between the concave and convex states. The proposed system was fabricated using a 3D printer with silicone material, and its bistable properties were evaluated. The measured resonant frequencies were 6.6 kHz in the concave state and 4.1 kHz in the convex state, resulting in dual-frequency noise reduction. In principle, the proposed HR design can be extended to a multi-stable mechanism that enables the attenuation of multiple frequencies.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"77 ","pages":"Article 102333"},"PeriodicalIF":4.3,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143834756","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

Rolling of a cylinder induced by electro-adhesive forces 由电附着力引起的圆筒的滚动

IF 4.3 3区工程技术

Extreme Mechanics Letters Pub Date : 2025-04-11 DOI: 10.1016/j.eml.2025.102324

Minchae Kang , Yeji Han , Gino Domel , Min-Woo Han , David R. Clarke

引用次数: 0

Mechanical performance of reconfigurable origami structures fabricated by cutting and planar assembly 可重构折纸结构切割与平面装配的力学性能

IF 4.3 3区工程技术

Extreme Mechanics Letters Pub Date : 2025-04-10 DOI: 10.1016/j.eml.2025.102332

Changlong Shi, Qian Zhang, Jian Feng, Jianguo Cai

{"title":"Mechanical performance of reconfigurable origami structures fabricated by cutting and planar assembly","authors":"Changlong Shi, Qian Zhang, Jian Feng, Jianguo Cai","doi":"10.1016/j.eml.2025.102332","DOIUrl":"10.1016/j.eml.2025.102332","url":null,"abstract":"<div><div>Origami structures with reconfigurable properties typically exhibit multifunctionality due to their diverse shape transformations. However, such structures often incorporate non-Euclidean vertices, rendering them non-developable and incapable of being flattened, and thus typically necessitate 3D printing for fabrication. In this study, a method of planar cutting and folding followed by assembly has been developed. The planar cut origami structure(PCOS), fabricated using this method, consists of non-Euclidean origami units that undergo transitions between mountain and valley folds during the folding process, granting the structure a high degree of reconfigurability. Through shape reconfiguration, the structure can achieve various self-locking and non-self-locking configurations. Compression tests in the Z-direction were conducted on multiple configurations, both self-locking and non-self-locking. The results demonstrate a significant difference in Z-direction compressive performance between the two types. When all units are self-locked, the peak stress reaches 139 kPa, representing an approximate 267 times increase compared to the non-self-locking configuration. Additionally, the mechanical performance is directly influenced by the number and distribution of self-locking units. By adjusting the self-locking units and their distribution, the peak stress of the model can be tuned to several gradient ranges, including 10<sup>0</sup> kPa, 10<sup>1</sup> kPa, 2 × 10<sup>1</sup> kPa, 3 × 10<sup>1</sup> kPa, and 10<sup>2</sup> kPa. This reconfiguration of mechanical properties, driven by geometric transformations, allows the planar cut origami structure to perform different functions depending on the environment, demonstrating significant potential for practical engineering applications.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"77 ","pages":"Article 102332"},"PeriodicalIF":4.3,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143843830","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

Front cover CO1 封面 CO1

IF 4.3 3区工程技术

Extreme Mechanics Letters Pub Date : 2025-04-10 DOI: 10.1016/S2352-4316(25)00040-9

引用次数: 0

Elastocapillary deformation prevents interfacial water trapping in underwater contact 弹性毛细管变形防止界面水捕获在水下接触

IF 4.3 3区工程技术

Extreme Mechanics Letters Pub Date : 2025-04-10 DOI: 10.1016/j.eml.2025.102326

Qihan Liu , M. Ravi Shankar

引用次数: 0

The mapping relationship between initiator and mechanical properties of free radical polymerized hydrogels 自由基聚合水凝胶引发剂与力学性能的映射关系

IF 4.3 3区工程技术

Extreme Mechanics Letters Pub Date : 2025-04-08 DOI: 10.1016/j.eml.2025.102327

Yujun Guo , Heng Zhu , Zhe Chen , Shaoxing Qu

{"title":"The mapping relationship between initiator and mechanical properties of free radical polymerized hydrogels","authors":"Yujun Guo , Heng Zhu , Zhe Chen , Shaoxing Qu","doi":"10.1016/j.eml.2025.102327","DOIUrl":"10.1016/j.eml.2025.102327","url":null,"abstract":"<div><div>Most of the hydrogels are formed by free radical polymerization of the precursor solution containing monomer, crosslinker, initiator, and water. The change of any one of the components will affect the final network structure, which will lead to different mechanical properties. Although the initiator plays a key role in the synthesis of hydrogels, the mapping relationship between the initiator and the mechanical properties of hydrogels has not been well explained. In this paper, a polyacrylamide hydrogel with high water content is taken as the research object. The influence of the initiator on the elastic modulus and toughness of the hydrogel is analyzed experimentally and theoretically. In theory, we reveal the microscopic mechanism of the initiator on the evolution of the network structure. By taking the kinetic chain length as an intermediate variable, a mechanochemical coupling model is developed to predict the relationship between the initiator and the elastic modulus. The theoretical predictions agree well with the experimental results. Furthermore, we find that initiators can tune the modulus of hydrogels, but have little effect on toughness. These mechanical changes induced by initiators provide more options for hydrogel applications. And utilizing the kinetic chain length as a characteristic parameter for the evolution of the network helps elucidate the impact of free radical polymerization reactions on macroscopic mechanical behavior.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"77 ","pages":"Article 102327"},"PeriodicalIF":4.3,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143816040","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

Unitary mechanical metamaterials with embedded one-qubit logic 嵌入单量子位逻辑的单一机械超材料

IF 4.3 3区工程技术

Extreme Mechanics Letters Pub Date : 2025-04-08 DOI: 10.1016/j.eml.2025.102330

Eduard G. Karpov, Kazi A. Rahman

引用次数: 0

Mechanics of out-of-plane screw dislocation in a 2D material 二维材料的面外螺旋位错力学

IF 4.3 3区工程技术

Extreme Mechanics Letters Pub Date : 2025-04-07 DOI: 10.1016/j.eml.2025.102320

Moon-ki Choi , Harley T. Johnson

{"title":"Mechanics of out-of-plane screw dislocation in a 2D material","authors":"Moon-ki Choi , Harley T. Johnson","doi":"10.1016/j.eml.2025.102320","DOIUrl":"10.1016/j.eml.2025.102320","url":null,"abstract":"<div><div>We study the mechanics of out-of-plane screw dislocations in two-dimensional (2D) materials using elastic membrane theory and atomistic simulations. Through elastic membrane theory, we derive a closed-form equation for the excess energy of the out-of-plane screw dislocation, revealing that the strain associated with the dislocation in a 2D material diminishes more rapidly with distance compared to that in a bulk material. We utilize this equation to compute energy profiles of out-of-plane screw dislocations in graphene. Various core radii across Burgers vectors (i.e., number of layers) under conditions with and without hydrogen termination on the dislocation core are considered, and computed energies are validated by atomistic simulations. Our results show that the screw dislocation core has a finite core radius which increases as the Burgers vector increases to avoid a high stress concentration at the dislocation core, thereby minimizing the total energy. Furthermore, we extend our theory to include the interaction between screw dislocations in a dipole configuration. Simulation results indicate that the relaxation narrows a high-strain concentration region near the dislocation core, where the interaction energy becomes negligible. Additionally, we examine the influence of out-of-plane screw dislocations on alternating twisted multilayer graphene. Our results reveal that the screw dislocation induces additional in-plane strain on the structure near the dislocation core, but that this additional strain is confined to within 2 nm of the dislocation core.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"77 ","pages":"Article 102320"},"PeriodicalIF":4.3,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143829480","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