Mechanics Research Communications最新文献

{"title":"Design of tensegrity torus based on bilevel optimization model","authors":"Jinyu Lu,&nbsp;Zhiyin Xu,&nbsp;Junwei Pan","doi":"10.1016/j.mechrescom.2023.104222","DOIUrl":"https://doi.org/10.1016/j.mechrescom.2023.104222","url":null,"abstract":"<div><p>This paper presents a design method for novel tensegrity<span><span> torus based on a bilevel optimization model. The novel tensegrity torus is assembled by a plurality of deformed three-rod prismatic tensegrity units, which can be uniquely determined by 5 geometric parameters<span>. Taking the five parameters as optimization variable, the uniformity of both geometry and prestress as </span></span>optimization objective, a bilevel optimization model is innovatively established. This model can integrate multiple optimization objectives and address nested optimization problems. Three numerical examples with different equal divisions are established and the optimization results indicate good effect of optimization model. Further parameter analysis of the bilevel optimization model demonstrates that reasonable constraints can enhance the optimization effect of the model. Compared to other equal divisions, the prestress of 18-division torus is the most uniform.</span></p></div>","PeriodicalId":49846,"journal":{"name":"Mechanics Research Communications","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138435974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vibration analysis of tri-directionally coated plate via thickness-stretching and microstructure-dependent modeling","authors":"Ahmed Amine Daikh ,&nbsp;Mohamed-Ouejdi Belarbi ,&nbsp;Pham Van Vinh ,&nbsp;Li Li ,&nbsp;Mohamed Sid Ahmed Houari ,&nbsp;Mohamed A. Eltaher","doi":"10.1016/j.mechrescom.2023.104221","DOIUrl":"https://doi.org/10.1016/j.mechrescom.2023.104221","url":null,"abstract":"<div><p><span>In this study, the tri-directionally-coated functionally graded plate has different levels of microstructure and is modeled more accurately using nonclassical mechanics incorporating the intrinsic characteristic lengths as well as using a spatial variation of material properties. The free vibration behavior of the tri-directionally-coated functionally graded plate is investigated using a refined quasi-3D higher-order shear deformation theory in conjunction with nonlocal </span>strain gradient theory. Based on the generalized field of displacement, the quasi-3D higher-order shear deformation theory is employed by reducing the number of variables from six to five variables. The equations of motion are performed based on the principle of Hamilton and solved by applying the Galerkin technique to cover various boundary conditions. Besides, the microstructure-dependent parameters, that is, the nonlocal parameter and the length scale parameter, also affect significantly the frequency of the tri-directionally-coated functionally graded plates. The multi-directionally-coated plate is softened when considering the nonlocal parameter; the multi-directionally-coated plate is, however, hardened when considering the length scale parameter.</p></div>","PeriodicalId":49846,"journal":{"name":"Mechanics Research Communications","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138483905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A mechanical derivation of the evolution equation for scintillating crystals: Recombination–diffusion–drift equations, gradient flows and Wasserstein measures","authors":"Fabrizio Daví","doi":"10.1016/j.mechrescom.2023.104218","DOIUrl":"https://doi.org/10.1016/j.mechrescom.2023.104218","url":null,"abstract":"<div><p>In a series of previous papers we obtained, by the means of the mechanics of continua with microstructure, the Reaction–Diffusion–Drift equation which describes the evolution of charge carriers in scintillators. Here we deal, first of all, with the consequences of constitutive assumptions for the entropic and dissipative terms. In the case of Boltzmann–Gibbs entropy, we show that the equation admits a gradient flows structure: moreover, we show that the drift–diffusion part is a Wasserstein gradient flow and we show how the energy dissipation is correlated with an appropriate Wasserstein distance.</p></div>","PeriodicalId":49846,"journal":{"name":"Mechanics Research Communications","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0093641323001775/pdfft?md5=d1c594dfbc33fe9f5d6b23894d3bf05e&pid=1-s2.0-S0093641323001775-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136696816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multiwalled carbon nanotubes as hard templates to yield advanced geopolymer-based self-assembled nanostructured ceramics","authors":"Yunzhi Xu ,&nbsp;Haklae Lee ,&nbsp;Nathanial Buettner ,&nbsp;Ange-Therese Akono","doi":"10.1016/j.mechrescom.2023.104216","DOIUrl":"https://doi.org/10.1016/j.mechrescom.2023.104216","url":null,"abstract":"<div><p>Novel multifunctional construction materials are needed to promote resilient infrastructure in the face of climate change and extreme weather. Nanostructured materials such as geopolymer reinforced with carbon-based nanomaterials are a promising way to reach that goal. In recent years, several studies have investigated the influence of nanomaterials on the physical properties of geopolymer composites such as compressive strength and fracture toughness. Yet, a fundamental understanding of the influence of nanomaterials on the nanoscale and micron-scale structure has been elusive so far. Our research objective is to understand how multiwalled carbon nanotubes (MWCNT) can help tailor the microstructure of geopolymers to yield architected multifunctional nanocomposites. We synthesized geopolymer nanocomposites reinforced with 50-nm thick multiwalled carbon nanotubes with mass fractions in the range of 0.1 wt%, 0.2 wt%, and 0.5 wt%. Our major finding is that MWCNTs act as hard templates that promote geopolymer formation via self-assembly. Geopolymer nanoparticle growth is observed along the walls of MWCNTs. A refinement in grain size is observed: increasing the fraction of MWCNTs by 0.5 wt% leads to a reduction in grain size by 54%. Similarly, increasing the mass fraction of MWCNTs leads to a densification of the geopolymer matrix as demonstrated by the Fourier transform infrared spectroscopy results and the statistical deconvolution analysis. Mercury intrusion porosimetry shows a nanoscale tailoring of the pore size distribution: a 26% decrease in porosity is observed as the fraction of MWCNTs is increased to 0.5 wt%. As a result of these nanoscale structural changes, a greater resistance to long-term deformation is observed for MWCNT-reinforced geopolymers, as the creep modulus increases both locally and macroscopically. At the macroscopic level, a 42% increase in the macroscopic logarithmic creep modulus is observed as the fraction of MWCNTs is increased to 0.5 wt%. These findings and the supporting methodology are important to understand how to manipulate matter below 100 nm. This research also paves the way for the design of resilient infrastructure materials with tailored microstructure and mechanical properties.</p></div>","PeriodicalId":49846,"journal":{"name":"Mechanics Research Communications","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"92025101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the partial wrinkling of imperfectly guided webs","authors":"Ciprian D. Coman","doi":"10.1016/j.mechrescom.2023.104214","DOIUrl":"https://doi.org/10.1016/j.mechrescom.2023.104214","url":null,"abstract":"<div><p>Flexible webs such as those used in roll-to-roll process machines are prone to various detrimental forms of elastic instabilities. This study revisits recent numerical work pertaining to the divergence buckling of non-uniformly tensioned axially moving thin webs. We show that the eigen-deformations experienced by these configurations are characterised by localised short-wavelength spatial patterns (typically referred to as ‘partial wrinkling’). The broader asymptotic structure of the associated bifurcation problem is also highlighted, while our theoretical predictions are further substantiated by additional assessments through direct numerical simulations.</p></div>","PeriodicalId":49846,"journal":{"name":"Mechanics Research Communications","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0093641323001738/pdfft?md5=00bbdfec2d1ab21eb7ba2ee8d40cbf39&pid=1-s2.0-S0093641323001738-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"92025099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-bounce resonances in the interaction of walking droplets","authors":"George Zhang ,&nbsp;Ivan C. Christov ,&nbsp;Aminur Rahman","doi":"10.1016/j.mechrescom.2023.104215","DOIUrl":"https://doi.org/10.1016/j.mechrescom.2023.104215","url":null,"abstract":"<div><p>Discrete dynamical models of walking droplets (“walkers”) have allowed swift numerical experiments revealing heretofore unobserved quantum statistics and related behaviors in a classical hydrodynamic system. We present evidence that one such model of walking droplets exhibits the empirically elusive <span><math><mi>n</mi></math></span>-bounce resonances that are traditionally seen in the scattering of solitary waves governed by covariant nonlinear field theories with polynomial self-interaction. A numerical investigation of the chosen model of interacting walking droplets reveals a fractal structure of resonances in the velocity in–velocity out diagram, much like the usual maps constructed for collisions of solitary waves. We suggest avenues for further theoretical analysis of walker collisions, which may connect this discrete model to the field-theoretic setting, as well as directions towards new experimental realizations <span><math><mi>n</mi></math></span>-bounce resonances.</p></div>","PeriodicalId":49846,"journal":{"name":"Mechanics Research Communications","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"92025098","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Kinematic behaviour of origami combining two four-crease vertices","authors":"David Xing,&nbsp;Zhong You","doi":"10.1016/j.mechrescom.2023.104213","DOIUrl":"10.1016/j.mechrescom.2023.104213","url":null,"abstract":"<div><p>The simplest rigidly foldable single-vertex origami structure is a four-crease origami (single 4C). It is a 1 DOF spherical linkage which possesses geometric properties that allow its copies to be combined into more complex rigidly foldable origami such as the Miura-ori. Merging two identical flat-foldable single 4Cs together produces a new construction, called the double 4C. We discover that this composite structure has some unique kinematic properties. Apart from being rigidly foldable and flat-foldable with 1 DOF, both single 4Cs in the double 4C are always in identical folded states. Moreover, it actually couples some panels together to form scissor-like mechanisms without physically crossing the panels. The double 4C can also have its kinematically equivalent thick-panel counterpart. By dissecting the double 4C and its thick panel counterpart, we find the constituent mechanisms forming them. We uncover how the constituent mechanisms evolve. Since the double 4C are fundamental units in many stackable tessellation origami structures, our kinematic analysis gives insight into the kinematic behaviour of these structures. Not only can the findings be used to guide the creation of thick panel counterparts of the stackable origami, but it may also enable the creation of new origami structures with single DOF by mimicking the vast number of deployable structures that contain scissor-like elements.</p></div>","PeriodicalId":49846,"journal":{"name":"Mechanics Research Communications","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0093641323001726/pdfft?md5=a41003943a3c8f000e80c827acbd42b6&pid=1-s2.0-S0093641323001726-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136128915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermo-mechanical experimental investigations of 3D-printed elastomeric polyurethane from low to intermediate strain rates","authors":"Jie Yang ,&nbsp;Zisheng Liao ,&nbsp;Mokarram Hossain ,&nbsp;Guanyu Huang ,&nbsp;Kai Wang ,&nbsp;Xiaohu Yao","doi":"10.1016/j.mechrescom.2023.104212","DOIUrl":"https://doi.org/10.1016/j.mechrescom.2023.104212","url":null,"abstract":"<div><p>Additively manufactured (3D-printed) elastomers have increasing applications in impact resistance devices such as helmets, shoe soles, and shock absorbing architectured metamaterials. These rapidly expanding areas require a proper understanding of the thermo-mechanical behaviours of soft polymers. In this contribution, thermal–mechanical properties of 3D-printed elastomeric polyurethane (EPU) are extensively characterised under low to high strain rates which are missing in the literature. The EPU under investigation is digitally manufactured using a Digital Light Synthesis (DLS) technology and is characterised by tensile experiments with a wide range of strain rates spanning from 0.001/s to 500/s and temperature variations of -20 °C to 60 °C. The experimental results reveal deformation nonlinearity, thermal-sensitivity, and strain rate-sensitivity in the elastomer. Moreover, the study reveals the occurrence of the glass transition phenomenon, which is commonly observed in soft materials under low-temperature and high strain-rate conditions. Various graphical illustrations are presented to depict the effects of temperature and strain rate on the stress response. It is observed that as temperature decreases or strain rate increases, the stress amplifies and becomes more sensitive to variations in temperature or strain rate. Additionally, higher strain levels further enhance the stress sensitivity to these variations. The microscopic mechanisms behind the thermal and strain rate sensitivities are discussed, taking into account the influence of the strain level. Overall, this study contributes to a proper understanding of the thermo-mechanical behaviours of digitally-printed soft polymers, particularly in dynamic scenarios.</p></div>","PeriodicalId":49846,"journal":{"name":"Mechanics Research Communications","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0093641323001714/pdfft?md5=1f8a866467cbf81ba1bf9acc866f2b5f&pid=1-s2.0-S0093641323001714-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"92025100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Kresling tube metamaterial exhibits extreme large-displacement buckling behavior","authors":"Emilio Turco ,&nbsp;Emilio Barchiesi ,&nbsp;Andrea Causin ,&nbsp;Francesco dell’Isola ,&nbsp;Margherita Solci","doi":"10.1016/j.mechrescom.2023.104202","DOIUrl":"https://doi.org/10.1016/j.mechrescom.2023.104202","url":null,"abstract":"<div><p>The present contribution proves that Kresling-patterned tubular origami metamaterials can exhibit a nonlinear buckling behavior in compression characterized by extremely significant and sudden twisting, as well as by extreme transverse dilation/contraction. It is proved that such an extreme buckling behavior can be achieved by tuning the ratio between stiffness parameters controlling the relative compliance of in-plane deformation of facets with respect to their bending and folding about creases. The modeling strategy adopted in the present contribution is discrete in nature and consists of an extensional-rotational spring model where energy barriers are introduced to prevent the interpenetration of adjacent facets.</p></div>","PeriodicalId":49846,"journal":{"name":"Mechanics Research Communications","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"92025086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A geometric-based method for the mesh stiffness evaluation of spur gears with spatial cracks","authors":"Bilal El Yousfi ,&nbsp;Abdenour Soualhi ,&nbsp;Kamal Medjaher","doi":"10.1016/j.mechrescom.2023.104203","DOIUrl":"https://doi.org/10.1016/j.mechrescom.2023.104203","url":null,"abstract":"<div><p><span><span>Bending fatigue is one of the most common failure modes of gear-based transmissions. Bending fatigue often manifests in the form of cracks at the gear tooth root, which propagates over the time, until a part of the tooth or the whole tooth is removed. Many papers have been published to determine the effect of this failure mode on the gear </span>system dynamics<span>, specifically, the gear mesh stiffness. But the majority of them considered uniform </span></span>propagation paths and distribution of the crack profile. Moreover, as we know, the effect of the crack initiation point on the mesh stiffness deformation has not been investigated previously.</p><p>In this study, a geometric-based method is proposed to investigate the effect of non-uniform crack faults on the gear mesh stiffness. This is realized by uncoupling the crack geometry modeling from the stiffness calculation equations, which will enable us to model any crack geometry without any change in the mathematical expressions of the stiffness components. Furthermore, limiting lines of a specific crack shape and initiation point are customized in this study to better consider the effect of random propagated cracks including reascending cracks on the mesh stiffness variation. Simulation results showed that the crack shape, length, and initiation point have a significant effect on the final deformation of the gear mesh stiffness.</p></div>","PeriodicalId":49846,"journal":{"name":"Mechanics Research Communications","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49867517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}