Mechanics Research Communications最新文献

{"title":"Topology optimization of extruded beams modeled with the XFEM for maximizing their natural frequencies","authors":"Ameer Marzok,&nbsp;Haim Waisman","doi":"10.1016/j.mechrescom.2023.104234","DOIUrl":"https://doi.org/10.1016/j.mechrescom.2023.104234","url":null,"abstract":"<div><p><span><span>In this paper, an efficient topology optimization approach is developed for maximizing the fundamental natural frequency of extruded beams. Mass fraction and static compliance bounds are defined using inequality-type constraints in the optimization problem. An XFEM approach, previously proposed by the authors for analyzing beam elements, is extended herein to compute the natural frequencies of the beam. The method allows for 3D modeling of beams with a significant reduction in the number of degrees of freedom and therefore also yields efficient optimization procedure. This reduction is made possible by incorporating global enrichment functions in the </span>longitudinal direction, which enables a significant reduction in the number of elements in that direction without loss of accuracy. A </span>nonlinear optimization<span><span> problem is formulated using continuous density-based design variables that represent the material distribution in the beam’s cross-section. The optimization problem is then solved using a gradient-based approach with analytical sensitivities. The well-known Solid Isotropic Material with Penalization (SIMP) method is used to acquire discrete solutions. We study the optimal design of short and long beams. It is shown that for short beams, localized vibration modes appear within the cross-section, leading to a significant distortion </span>deformation mode<span> of the cross-section. The optimized design of the long beam shows global deformation modes with an increase of 15% in the fundamental frequency compared with a non-optimized design consisting of a hollow rectangular cross-section with the same mass.</span></span></p></div>","PeriodicalId":49846,"journal":{"name":"Mechanics Research Communications","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138570169","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 refined fractional viscoelastic model for vibration analysis of moderately-thick plates","authors":"Mahsa Vazirzadeh ,&nbsp;Jafar Rouzegar ,&nbsp;Mohammad Hossein Heydari","doi":"10.1016/j.mechrescom.2023.104224","DOIUrl":"10.1016/j.mechrescom.2023.104224","url":null,"abstract":"<div><p>In this study, a Kelvin–Voigt fractional viscoelastic model is developed based on the two-variable refined plate theory (TV-RPT) to investigate the dynamic behavior of rectangular viscoelastic plates under support movement. The TV-RPT is a novel, simple, and efficient plate theory that provides accurate results for both thin and thick plates. The steady-state condition is governed by assuming the lower limit of the integral in the Riemann-Liouville fractional derivative<span> to be negative infinity. After deriving the governing equation, an analytical solution based on the Navier method is employed for fully simply-supported viscoelastic plates. The proposed approach is validated by comparing the natural frequencies of viscoelastic and elastic plates with existing results in the literature. Additionally, the results obtained from TV-RPT and the classical plate theory<span> (CPT) are compared. It is observed that both theories provide similar results for thin plates. However, for thicker plates, the amplitude and frequency of vibrations for TV-RPT are smaller and larger than those for CPT, respectively. The study also investigates the effects of fractional derivative order and damping coefficient on the frequency and amplitude of vibration.</span></span></p></div>","PeriodicalId":49846,"journal":{"name":"Mechanics Research Communications","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138607808","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 rotary inertia of microstuctured beams and variations thereof","authors":"V. Eremeyev, Isaac Elishakoff","doi":"10.1016/j.mechrescom.2023.104239","DOIUrl":"https://doi.org/10.1016/j.mechrescom.2023.104239","url":null,"abstract":"","PeriodicalId":49846,"journal":{"name":"Mechanics Research Communications","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139015989","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":"Fabric controls on fracture surface roughness of an architected rock material","authors":"Chaoyi Wang ,&nbsp;Liyang Jiang ,&nbsp;Antonio Bobet ,&nbsp;Hongkyu Yoon ,&nbsp;Laura J. Pyrak-Nolte","doi":"10.1016/j.mechrescom.2023.104223","DOIUrl":"https://doi.org/10.1016/j.mechrescom.2023.104223","url":null,"abstract":"<div><p>Fluid flow through fractures is intimately linked to the fracture surfaces that define the void geometry through which fluids flow. Thus, an understanding of what controls fracture surface roughness is essential to the development of models for predicting fluid transport through fractured rock. The difficulty in predicting surface roughness arises from the complexity of rock which is inherently heterogeneous and nonuniform in composition, fabric, and structural components, even when samples are acquired from the same rock mass. Here, a benchmarked-simulation approach motivated from geo-architected 3D printed synthetic gypsum rocks is used to provide insight into the competing contributions from fabric and layering on fracture roughness formation. Simulation results from a discrete element model (Particle Flow Code, Itasca Consulting Group, Inc.) clearly indicate that the relative orientation between mineral layers and in-layer mineral fabric, and the variability in mineral bonding strengths determine whether anisotropic corrugated surfaces or isotropic surfaces are formed. Weak mineral layers oriented perpendicular to the applied load resulted in strong roughness anisotropy. Peak failure loads were found to vary up to 30% depending on the strength of the mineral fabric at the location of fracture initiation, which provides insight into the observed high variability in strength values of natural rock. The uniqueness of induced fracture roughness and peak failure load is intimately linked to layering, mineral fabric, and their distribution in the rock. These findings have important implications for any architected material fabricated through serial printing of layers with local compositional heterogeneity.</p></div>","PeriodicalId":49846,"journal":{"name":"Mechanics Research Communications","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0093641323001829/pdfft?md5=8c1b0b0521ad10a2e44d68841d0157d3&pid=1-s2.0-S0093641323001829-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138484705","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":"Influence functions for accurate representation of bond deformation in discrete modeling","authors":"Hailong Chen ,&nbsp;Xuan Hu","doi":"10.1016/j.mechrescom.2023.104220","DOIUrl":"https://doi.org/10.1016/j.mechrescom.2023.104220","url":null,"abstract":"<div><p>Continuum-like nonlocal deformation gradients have been constructed based on discrete simulation results. In this paper, the accuracy of the nonlocal deformation gradient based on different influence functions is examined for both representing material point deformation and mapping bonds. A new class of parameterized influence functions that accounts for both bond relative length and angle (with respect to a target bond) is proposed. Numerical example shows great accuracy of the nonlocal deformation gradient using the proposed influence functions in both representing material point deformation and mapping bonds. It is concluded that the proposed influence functions can be used to accurately capture bond-level continuum-like measures.</p></div>","PeriodicalId":49846,"journal":{"name":"Mechanics Research Communications","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138435950","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":"Discrete dynamical model for the hydrodynamic analog of a quantum mirage","authors":"Gonzalo F. Quinto ,&nbsp;Aminur Rahman","doi":"10.1016/j.mechrescom.2023.104219","DOIUrl":"https://doi.org/10.1016/j.mechrescom.2023.104219","url":null,"abstract":"<div><p>Recently discrete dynamical models of walking droplet dynamics have allowed for fast numerical simulations of their horizontal chaotic motion and consequently the long-time statistical distribution of the droplet position. We develop a discrete model for walkers on an elliptical corral with two dominant eigenmodes. These eigenmodes are excited periodically with each having random, but correlated, weights. At each iteration the model computes the horizontal propulsion of the droplet due to impacts with the fluid bath. The propulsion is calculated based on the interaction of the droplet and the wavefield produced by the eigenmode excitations, with the droplet being propelled perpendicular (rather than parallel) to the wave gradient. We record the long-time statistics, and remarkably for a dynamical system with some non-physical assumptions, they are qualitatively similar to that of experiments.</p></div>","PeriodicalId":49846,"journal":{"name":"Mechanics Research Communications","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138435949","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":"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}