Mechanics Research Communications最新文献_第9页

Centrifugal and gyroscopic effects on dynamic response of rotating cantilever beams under step loading 离心和陀螺效应对阶梯加载下旋转悬臂梁动力响应的影响

IF 2.4 4区工程技术

Mechanics Research Communications Pub Date : 2023-10-01 DOI: 10.1016/j.mechrescom.2023.104185

Hedi Hamdi , Adel Hamdi , Rachid Nasri

{"title":"Centrifugal and gyroscopic effects on dynamic response of rotating cantilever beams under step loading","authors":"Hedi Hamdi , Adel Hamdi , Rachid Nasri","doi":"10.1016/j.mechrescom.2023.104185","DOIUrl":"10.1016/j.mechrescom.2023.104185","url":null,"abstract":"<div>In this paper, a simplex finite element model for beams (FEMB) with a complete formulation is presented to study the dynamics of rotating cantilever beams subjected to distributed external loads. In our approach, the finite element method (FEM) and Timoshenko's beam theory is used. We will, particularly, examine the centrifugal and gyroscopic effects on the linear vibration of a rotating cantilever beam in stationary regime. In this model, extension, bending, and torsion degrees of freedom (DOF) are combined using a parameterization of the 3D motion of the beam by Euler's three-angle sequence. That allows identifying all the terms of the gyroscopic coupling in a more compact equations system. To ensure convergence, a sufficient number of finite elements are required in this model. The considered beam in the numerical simulation is pre-twisted and linearly tapered with a rectangular section. Results show that the dynamic centrifugal effect decreases the natural frequencies of the beam. Furthermore, the gyroscopic coupling induces rapid extension and torsion beatings when the beam undergoes a step bending load. Without damping, these beatings can persist and cause material fatigue.</div>","PeriodicalId":49846,"journal":{"name":"Mechanics Research Communications","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48503897","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}

引用次数: 0

A variegated effective elastic modulus in metabeams under periodically distributed loads 周期性分布荷载作用下元梁的变化有效弹性模量

IF 2.4 4区工程技术

Mechanics Research Communications Pub Date : 2023-10-01 DOI: 10.1016/j.mechrescom.2023.104166

Eduard G. Karpov, Debajyoti Saha

{"title":"A variegated effective elastic modulus in metabeams under periodically distributed loads","authors":"Eduard G. Karpov, Debajyoti Saha","doi":"10.1016/j.mechrescom.2023.104166","DOIUrl":"https://doi.org/10.1016/j.mechrescom.2023.104166","url":null,"abstract":"<div>A class of beam-like lattice structures, or metabeams under static, sinusoidally distributed transverse loads is discussed. Their neutral axis deflects either in-phase, out-of-phase or shows no deflection, depending on the beam design parameters, and also on the spatial frequency of the static load. These outcomes contrast the behavior of continuum beams, deflecting always in-phase with the load, and they are interpreted on the basis of a positive, negative and near-infinite effective Young's modulus of the structured beams in bending. They also represent a collective effect of the behavior of multiple elements in the lattice that cannot be realized from the performance of an isolated unit cell. A long-range periodic order and nonlocality of the lattice interaction is essential for this unusual behaviors, and those are particularly pronounced at higher wavenumbers, when the load wavelength becomes comparable with the range of direct interactions in the lattice. Theoretical discussion and predictions agree well with numerical experiments performed on the basis of commonly accepted models. Practical applications could be found in advanced reinforcing materials for building foundations, deformation mitigation for lightweight structures and bridges, and in smart mechanical systems able to differentiate external stimuli and to respond selectively.</div>","PeriodicalId":49846,"journal":{"name":"Mechanics Research Communications","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49864709","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}

引用次数: 0

Rare rogue fluctuations could be generic to strongly nonlinear and non-integrable systems 罕见的流氓波动可能是强非线性和不可积系统的普遍现象

IF 2.4 4区工程技术

Mechanics Research Communications Pub Date : 2023-10-01 DOI: 10.1016/j.mechrescom.2023.104179

Rahul Kashyap , Surajit Sen

引用次数: 0

Effects of Kerr-type viscoelastic coupling layer with different stiffnesses on stochastic stability of Rayleigh double beams 不同刚度kerr型粘弹性耦合层对瑞利双梁随机稳定性的影响

IF 2.4 4区工程技术

Mechanics Research Communications Pub Date : 2023-10-01 DOI: 10.1016/j.mechrescom.2023.104181

Dunja Milić , Jian Deng , Vladimir Stojanović , Marko D. Petković

{"title":"Effects of Kerr-type viscoelastic coupling layer with different stiffnesses on stochastic stability of Rayleigh double beams","authors":"Dunja Milić , Jian Deng , Vladimir Stojanović , Marko D. Petković","doi":"10.1016/j.mechrescom.2023.104181","DOIUrl":"10.1016/j.mechrescom.2023.104181","url":null,"abstract":"<div>This paper discusses the stochastic stability of a double Rayleigh beam system connected by a Kerr-type three-parameter elastic layer with two different stiffnesses, under compressive axial loads. The beams are modeled using the Rayleigh beam theory, and the axial forces consist of a constant component and a time-dependent stochastic function. The study investigates the almost-sure and moment stability of the double beam system subjected to stochastic compressive axial loading, utilizing the Lyapunov exponent and moment Lyapunov exponents. In the case of weak noise excitations, a singular perturbation method is employed to derive second-order expansions of the moment Lyapunov exponent and the Lyapunov exponent. Monte Carlo simulation is included to validate the obtained results. A numerical study is conducted for selected parameters, and the almost-sure and moment stability in the first and second perturbation are graphically presented. The results provide insights into the influences of different stiffnesses, damping, and the shear parameter of the Kerr-type layer on the stochastic stability of the coupled Rayleigh beam mechanical system, considering the effects of rotational inertia. It is quantitatively and qualitatively determined that reducing the stiffness of one part of the Kerr-type layer leads to a decrease in the stable region of stochastic stability, while reducing the shear parameter results in an increase in the stable region of stochastic stability. Furthermore, a quantitative relationship between different dampings of the Kerr-type viscoelastic layer is determined, where increasing either of the two damping parameters leads to an expansion of the stable region of stochastic stability. The inclusion of rotational inertia effects through the Rayleigh beam theory contributes to more accurate approximations of the obtained solutions.</div>","PeriodicalId":49846,"journal":{"name":"Mechanics Research Communications","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41427373","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}

引用次数: 0

Influence of nozzle design on flow, mixing, and fluidisation in a bubbling bed fluidised by a single nozzle 喷嘴设计对单喷嘴流化床中流动、混合和流化的影响

IF 2.4 4区工程技术

Mechanics Research Communications Pub Date : 2023-10-01 DOI: 10.1016/j.mechrescom.2023.104180

D. Werner , C.R.K. Windows-Yule , Tz. Kokalova-Wheldon , J.P.K. Seville

引用次数: 0

Continuous softening up to the onset of failure: A hyperelastic modelling approach with intrinsic softening for isotropic incompressible soft solids 连续软化直至失效：各向同性不可压缩软固体的超弹性建模方法

IF 2.4 4区工程技术

Mechanics Research Communications Pub Date : 2023-10-01 DOI: 10.1016/j.mechrescom.2023.104183

Afshin Anssari-Benam

{"title":"Continuous softening up to the onset of failure: A hyperelastic modelling approach with intrinsic softening for isotropic incompressible soft solids","authors":"Afshin Anssari-Benam","doi":"10.1016/j.mechrescom.2023.104183","DOIUrl":"10.1016/j.mechrescom.2023.104183","url":null,"abstract":"<div>This paper seeks to put forward an alternative notion for modelling the continuous softening in the finite deformation of incompressible isotropic rubber-like materials, up to the onset of failure. Based on the proposition that ‘there is no fundamental reason as to why the basic constitutive parameters of the (hyper)elastic state of a material cannot determine the natural evolution of softening and failure in that material’, the concept of hyperelasticity with intrinsic softening is posited. In contrast to the currently available theories of continuum damage mechanics and energy limiters, which superpose external parameters onto the basic hyperelastic model, the alternative approach presented here postulates that if a hyperelastic strain energy function accommodates a comprehensive set of constitutive parameters and has an appropriate functional form, it will intrinsically capture the observed continuous softening in the stress–deformation curves of soft solids, up to the onset of failure. Examples of this notion are presented using a specific hyperelastic model previously proposed by the author, applied here to extant datasets of a wide variety of isotropic incompressible soft solids, ranging from soft tissues to protein gels and 3D printed biomaterials, that include the softening behaviour. The favourable modelling results obtained via this approach are demonstrated. It is conferred that these results portend a versatile modelling tool for application to the whole-range deformation of soft solids, up to the onset of failure, and make the case for devising a unified theory for modelling both continuous and discontinuous softening in the finite deformation of rubber-like materials.</div>","PeriodicalId":49846,"journal":{"name":"Mechanics Research Communications","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43680004","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}

引用次数: 1

Dislocation equilibrium in a misfitted composite structure with partially coherent interfaces 部分共融界面错配复合结构中的位错平衡

IF 2.4 4区工程技术

Mechanics Research Communications Pub Date : 2023-10-01 DOI: 10.1016/j.mechrescom.2023.104168

Jérôme Colin

引用次数: 1

Lattice modes of periodic origami tessellations with voids 带空洞的周期折纸镶嵌的晶格模式

IF 2.4 4区工程技术

Mechanics Research Communications Pub Date : 2023-10-01 DOI: 10.1016/j.mechrescom.2023.104167

Anandaroop Lahiri, Phanisri P. Pratapa

{"title":"Lattice modes of periodic origami tessellations with voids","authors":"Anandaroop Lahiri, Phanisri P. Pratapa","doi":"10.1016/j.mechrescom.2023.104167","DOIUrl":"10.1016/j.mechrescom.2023.104167","url":null,"abstract":"<div>Elastic modes of origami lattices are of scientific value in the context of metamaterial applications. Miura-ori is a well-studied origami pattern, especially in engineering. A deeper understanding of spatially homogeneous deformations can be useful to homogenization-based material characterization. Miura-ori with rigid parallelogram panels deforms exclusively through crease-folding as a single degree of freedom (DOF) system. Substituting parallelograms with rigid triangular panels introduces two additional DOFs per vertex and could admit a rich space of lattice deformations. In this paper, we investigate the lattice modes of rigid triangulated Miura-ori (RTM) with enclosed voided regions within the tessellations. We use two widely adopted approaches — the bar and hinge framework (BHF) and a folding-angle framework (FAF), that are typically used for the analysis of origami lattices. Unlike the 2D RTM lattice without voids, we find that for the origami lattices with voids, the compatibility constraints based on the crease folding-angles alone are insufficient to capture the admissible deformation modes. Additional loop-closure constraints, based on Denavit–Hartenberg analysis of spatial linkages, must be imposed on creases around each enclosed void. We observe that the homogeneous modes with accumulation of deformations across the lattice are exclusive to the space of Bloch-wave modes within the FAF approach and are not straightforwardly obtained using BHF approach of modeling origami lattices. The 2D RTM lattices with voids, irrespective of the size and aspect ratio of enclosed voids, are found to exhibit exactly six such exclusive FAF modes which can be further characterized using intuitively defined relations between crease angle perturbations.</div>","PeriodicalId":49846,"journal":{"name":"Mechanics Research Communications","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42845030","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}

引用次数: 0

Self-consistent homogenization approach for polycrystals within second gradient elasticity 二阶梯度弹性下多晶体的自洽均匀化方法

IF 2.4 4区工程技术

Mechanics Research Communications Pub Date : 2023-10-01 DOI: 10.1016/j.mechrescom.2023.104162

Yury Solyaev

{"title":"Self-consistent homogenization approach for polycrystals within second gradient elasticity","authors":"Yury Solyaev","doi":"10.1016/j.mechrescom.2023.104162","DOIUrl":"10.1016/j.mechrescom.2023.104162","url":null,"abstract":"<div>In this paper, we propose a generalized variant of Kröner’s self-consistent scheme for evaluation of the effective standard and gradient elastic moduli of polycrystalline materials within Mindlin-Toupin second-gradient elasticity theory. Assuming random orientation of crystallites (grains) we use an extended Eshelby’s equivalent inclusion method and mapping conditions between the prescribed linear distribution of macro-strain and corresponding micro-scale field variables averaged over the volume and all possible orientations of single grain. It is found that the developed self-consistent scheme predicts an absence of gradient effects at the macro-scale level for the model of ellipsoidal grains made of the first gradient (Cauchy-type) material. However, for the case of the second gradient crystallites, established approach allows to obtain a set of non-linear relations for determination of all effective standard and gradient elastic moduli of polycrystals. Example of calculations under simplified constitutive assumptions is presented for the model of anisotropic cubic Fe crystallites with spherical shape. It is shown that the presented approach predicts an increase of the effective length scale parameter of polycrystalline aggregates due to misorientation of grains axes and takes into account the size effects related to the mean diameter of grains.</div>","PeriodicalId":49846,"journal":{"name":"Mechanics Research Communications","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46616855","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}

引用次数: 0

Self-consistent approximations for the tangential-displacement correction to the incremental indentation stiffness 增量压痕刚度切向位移修正的自洽近似

IF 2.4 4区工程技术

Mechanics Research Communications Pub Date : 2023-10-01 DOI: 10.1016/j.mechrescom.2023.104186

Ivan Argatov , Xiaoqing Jin

引用次数: 0