Mechanics Research Communications最新文献_第4页

Non-locality as a regularization mechanism in elastodynamics 作为弹性动力学正则化机制的非位置性

IF 2.4 4区工程技术

Mechanics Research Communications Pub Date : 2024-04-24 DOI: 10.1016/j.mechrescom.2024.104280

J.R. Fernández , R. Quintanilla

{"title":"Non-locality as a regularization mechanism in elastodynamics","authors":"J.R. Fernández , R. Quintanilla","doi":"10.1016/j.mechrescom.2024.104280","DOIUrl":"10.1016/j.mechrescom.2024.104280","url":null,"abstract":"<div><p>It is well known that the solutions to the elastodynamic problem do not satisfy continuous dependence properties on the initial values, and/or supply terms, when the elastic tensor fails to be positive. In fact, the behavior of the solutions can be very explosive since the elements of the spectrum can go to infinite. Therefore, it is very relevant to identify thermomechanical mechanisms regularizing the behavior of the solutions. So, the main aim of this note is to show, from an analytical point of view, how the <em>non-locality</em>, in the sense of Eringen, is a mechanism satisfying this property of regularization of the solutions. It is worth noting that such system has not been previously studied from an analytical point of view. We firstly obtain the existence of the solutions to this problem, even when we do not assume any positivity on the elastic tensor. This result is proved with the help of the linear semigroups theory; however, even with these regularizing effects, the solutions to this problem are unstable. A particular easy one-dimensional problem is also considered. The extension of the existence and instability results to the thermoelastic case is pointed out later. Finally, we also study the spatial behavior of the solutions to the problem in the case that the region is a semi-infinite cylinder, and we obtain a Phragmen–Lindelöf alternative of the exponential type. This result is also relevant because a similar result, without considering regularizing terms, is unknown if the elastic tensor is not positive definite.</p></div>","PeriodicalId":49846,"journal":{"name":"Mechanics Research Communications","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0093641324000405/pdfft?md5=994a15812920cf093c2e25e6b0fb04b0&pid=1-s2.0-S0093641324000405-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140758618","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}

引用次数: 0

Vibration transmission characteristics of the pyramidal cylinder lattice truss structure 金字塔圆柱体格构桁架结构的振动传递特性

IF 2.4 4区工程技术

Mechanics Research Communications Pub Date : 2024-04-22 DOI: 10.1016/j.mechrescom.2024.104279

Xin Xue , Zeyu Li , Fang Wu , Yuhan Wei , Yichuan Shao , Mangong Zhang , Juan Liao

引用次数: 0

Discrete modeling of elastic heterogeneous media 弹性异质介质的离散建模

IF 2.4 4区工程技术

Mechanics Research Communications Pub Date : 2024-04-19 DOI: 10.1016/j.mechrescom.2024.104277

Q. Zhang , J. Eliáš , K. Nagai , J.E. Bolander

引用次数: 0

A multiscale fracture model using peridynamic enrichment of finite elements within an adaptive partition of unity: Experimental validation 在自适应统一分区中使用周动态丰富有限元的多尺度断裂模型：实验验证

IF 2.4 4区工程技术

Mechanics Research Communications Pub Date : 2024-04-15 DOI: 10.1016/j.mechrescom.2024.104275

Matthias Birner , Patrick Diehl , Robert Lipton , Marc Alexander Schweitzer

{"title":"A multiscale fracture model using peridynamic enrichment of finite elements within an adaptive partition of unity: Experimental validation","authors":"Matthias Birner , Patrick Diehl , Robert Lipton , Marc Alexander Schweitzer","doi":"10.1016/j.mechrescom.2024.104275","DOIUrl":"https://doi.org/10.1016/j.mechrescom.2024.104275","url":null,"abstract":"<div><p>Partition of unity methods (PUM) are of domain decomposition type and provide the opportunity for multiscale and multiphysics numerical modeling. Here, we apply Peridynamic (PD) enrichment to propagate cracks in the PUM global–local enrichment scheme. We apply linear elasticity globally and PD over local zones where fractures occur. The elastic fields provide appropriate boundary data for local PD simulations on a subdomain containing the crack tip to grow the crack. Once the updated crack path is found the elastic field in the body and surrounding the crack is updated using the PUM basis with an elastic field enrichment near the crack. The subdomain for the PD simulation is chosen to include the current crack tip as well as features that influence crack growth. This paper is part II of this series and validates the combined PD/PUM simulator against the experimental results. The results of numerical simulation show that we attain good agreement between experiment and simulation with a local PD subdomain that is moving with the crack tip and adaptively chosen size.</p></div>","PeriodicalId":49846,"journal":{"name":"Mechanics Research Communications","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140605772","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

Bandgap structure of tensegrity mass–spring chains equipped with internal resonators 配备内部谐振器的张力质量弹簧链的带隙结构

IF 2.4 4区工程技术

Mechanics Research Communications Pub Date : 2024-04-13 DOI: 10.1016/j.mechrescom.2024.104273

Luca Placidi , Julia de Castro Motta , Fernando Fraternali

{"title":"Bandgap structure of tensegrity mass–spring chains equipped with internal resonators","authors":"Luca Placidi , Julia de Castro Motta , Fernando Fraternali","doi":"10.1016/j.mechrescom.2024.104273","DOIUrl":"https://doi.org/10.1016/j.mechrescom.2024.104273","url":null,"abstract":"<div><p>This work studies the dispersion relation of a Maxwell type mass–spring chain formed by lumped masses and the parallel arrangement of two different types of tensegrity prisms. Use is made of the Bloch–Floquet theory of discrete systems in association with a linearized model of the response of the tensegrity units under compression loading. Such a modeling is aimed at studying the propagation of compression waves under small perturbations of the initial equilibrium state of the system. For a given value of the cable’s prestress, the tensegrity systems connecting the lumped masses react as elastic springs, which exhibit axial deformations accompanied by relative twisting rotations of the terminal bases. The twisting motion of the chain affects the expression of the kinetic energy, and is accounted for by introducing a suitable definition of equivalent masses. The bandgap structure of the analyzed system is analytically determined and numerical results are obtained for a chain formed by physical models tensegrity <span><math><mrow><mi>θ</mi><mo>=</mo><mn>1</mn></mrow></math></span> prisms aligned in parallel with minimal tensegrity prisms. The given results highlight the highly tunable frequency bandgap properties of tensegrity mass–spring chains exhibiting internal resonance capabilities.</p></div>","PeriodicalId":49846,"journal":{"name":"Mechanics Research Communications","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140555657","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

Analysis of a tensegrity camber morphing airfoil 张弦外倾变形机翼分析

IF 2.4 4区工程技术

Mechanics Research Communications Pub Date : 2024-04-10 DOI: 10.1016/j.mechrescom.2024.104272

Heping Liu, Jian Song, Ani Luo

引用次数: 0

Discontinuity waves in temperature and diffusion models 温度和扩散模型中的不连续波

IF 2.4 4区工程技术

Mechanics Research Communications Pub Date : 2024-04-08 DOI: 10.1016/j.mechrescom.2024.104274

Michele Ciarletta , Brian Straughan , Vincenzo Tibullo

引用次数: 0

Motion behavior of a 30-strut locomotive tensegrity robot 30 支杆机车张力结构机器人的运动行为

IF 2.4 4区工程技术

Mechanics Research Communications Pub Date : 2024-04-05 DOI: 10.1016/j.mechrescom.2024.104270

Meijia Wang , Yafeng Wang , Ruhe Mei , Zhaojun Liu , Xian Xu

{"title":"Motion behavior of a 30-strut locomotive tensegrity robot","authors":"Meijia Wang , Yafeng Wang , Ruhe Mei , Zhaojun Liu , Xian Xu","doi":"10.1016/j.mechrescom.2024.104270","DOIUrl":"https://doi.org/10.1016/j.mechrescom.2024.104270","url":null,"abstract":"<div><p>Tensegrity structure is a prestressed self-equilibrated system consisting of compressed struts and tensioned tendons. The shape and position of tensegrity can be actively controlled by changing the lengths of members, making it attractive as a platform for adaptive bionic and locomotive robots. In this paper, the regular 30-strut tensegrity is used as the skeleton of a locomotive robot. The robot is flexible and highly redundant, making it adaptive to unconstrained environments and ideal for various co-robotic scenarios such as space exploration, emergency rescue, and so on. Compared with the 6-strut tensegrity robot, the 30-strut tensegrity robot with more controllable degrees of freedom possesses more various motion behaviors as well as gait primitives. To demonstrate the effectiveness of the motion behaviors of the 30-strut locomotive robot, we analyze the diverse collection of behaviors generated by actively changing the lengths of struts. It is found that rolling motion is robust and easy to be actuated, and multi-gait and individual-gait of rolling motion are observed. However, its high dimensionality and strong dynamic nature complicate the motion control. A physical prototype is manufactured to verify the found motion behaviors. The results show the potential uses of 30-strut tensegrity as multifunctional locomotive robots.</p></div>","PeriodicalId":49846,"journal":{"name":"Mechanics Research Communications","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140535468","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

Analytical definitions of connectivity, incidence and node matrices for t-struts tensegrity prisms t-struts 张弦棱柱体连通性、入射和节点矩阵的分析定义

IF 2.4 4区工程技术

Mechanics Research Communications Pub Date : 2024-03-30 DOI: 10.1016/j.mechrescom.2024.104271

Victor A.S.M. Paiva , Paulo R.G. Kurka , Jaime H. Izuka

引用次数: 0

Active elastic metamaterials with equidistant solely resonant bandgaps 具有等距唯一谐振带隙的有源弹性超材料

IF 2.4 4区工程技术

Mechanics Research Communications Pub Date : 2024-03-19 DOI: 10.1016/j.mechrescom.2024.104269

Hasan B. Al Ba’ba’a

{"title":"Active elastic metamaterials with equidistant solely resonant bandgaps","authors":"Hasan B. Al Ba’ba’a","doi":"10.1016/j.mechrescom.2024.104269","DOIUrl":"10.1016/j.mechrescom.2024.104269","url":null,"abstract":"<div><p>Elastic metamaterials are man-made structures with properties that transcend naturally occurring materials. One predominant feature of elastic metamaterials is locally resonant bandgaps, i.e., frequency ranges at which wave propagation is blocked. Locally resonant bandgaps appear at relatively low frequency and arise from the existence of periodically placed mechanical local resonators. Typically, elastic metamaterials exhibit both locally resonant and Bragg-scattering bandgaps, which can generally be different in width and frequency ranges. This paper proposes two designs of active elastic metamaterials that only exhibit locally resonant bandgaps, which are infinite in number, evenly spaced in the frequency spectrum, and identical in width. The mathematical model is established using the transfer matrix method and synthesis of locally resonant bandgaps is achieved via an active elastic support with carefully designed frequency-dependent stiffness. A single unit cell of each proposed metamaterials is thoroughly studied, and its dispersion relation is derived analytically, along with the periodically repeating bandgap limits and widths. Following the dispersion analysis and bandgap parametric studies, finite arrays of the proposed metamaterials are considered, and their frequency response is calculated to verify the analytical predictions from dispersion analyses.</p></div>","PeriodicalId":49846,"journal":{"name":"Mechanics Research Communications","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140182402","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