论文快速发表网

社科类论文科技类论文医学类论文管理类论文教育类论文农林类论文新闻类论文建筑类论文文艺类论文法学类论文

EI Compendex Source List（2022年1月） EI Compendex Source List（2020年1月） EI Compendex Source List（2019年5月） EI Compendex Source List（2018年9月） EI Compendex Source List（2018年5月） EI Compendex Source List（2018年1月）中国科学引文数据库来源期刊列 CSSCI(2017-2018)及扩展期刊目录 2017年4月7日EI检索目录（最新） 2017年3月EI检索目录最新公布北大中文核心期刊目录 SCI期刊（含影响因子）

本站服务项目浅谈青年教师如何开展教科研大学青年教师如何处理教学和科

论文范文

Dynamics Analysis of Deployable Structures considering a Two-Dimensional Coupled Thermo-Structural Ef 时间:2018-10-09 22:57   来源:未知   作者:admin   点击: 次 Abstract:The deployment accuracy of deployable structures is affected by temperature and flexibility. To obtain the higher accuracy, various measures such as the optimization design and the control process are employed, and they are all based on deployment dynamics characteristics of deployable structures. So a precise coupled thermo-structural deployment dynamics analysis is important and necessary. However, until now, only a one-dimensional thermal effect is considered in the literatures because of simplicity, which reduces the accuracy of the model. Therefore, in this paper, a new model coupling mechanical field with a temperature field is presented to analyze the deployment dynamics of a deployable structure with scissor-like elements (SLEs). The model is based on the absolute nodal coordinate formulation (ANCF) and is established via a new locking-free beam element whose formulation is extended to account for the two-dimensional thermally induced stresses due to the heat expansion for the first time. Namely, in the formulation, the thermal influences are along two-dimensional directions, the axial direction and the transverse direction, rather than along a one-dimensional direction. The validity and precision of the proposed model are verified using a flexible pendulum example. Finally, the dynamics of a linear deployable structure with three SLEs modeled by the element is simulated under a temperature effect.
1. Introduction
  Over the past three decades, deployable structures have been extensively used in space missions because they own the properties of high stiffness, low mass, and small folding volume [1–4]. And with the rapid development of aerospace industry, higher demands for these structures have been proposed. One of the most important is higher deployment accuracy, which is affected by thermal and flexible effects [5].
  In order to achieve higher accuracy, the precise deployment dynamics characteristic of deployable structures is essential because it is fundamental to the optimization design [6] and the control process [7]. However, due to the high cost of the imitated space environment on the ground, it is difficult to predict the dynamic capability of these structures by experiment. So some practical methods are developed for dynamic analysis of these flexible structures. The most classical approach is the floating frame of reference formulation [8], but it is deficient in dynamic stiffening and will lead to an imprecise simulation result. To overcome this drawback, Shabana presented a new approach called the absolute nodal coordinate formulation (ANCF) [9], which can satisfy the dynamic stiffening automatically [10, 11] and leads to a constant mass matrix and zero centrifugal and Coriolis forces [12]. Because of these advantages, several beam elements [11, 13–16], plate elements [17], and brick elements [18] applied to analyze various objects of study have been developed within this formulation. A two-dimensional shear beam element proposed by Omar and Shabana [11] to consider the shear deformation effect is among them. However, in a later research, it was found out that this beam element deriving elastic forces on the basis of the nonlinear elastic theory suffers from volumetric Poisson’s locking, thickness locking, and shear locking, which influence the accuracy and computational efficiency of ANCF greatly [19, 20]. In order to avoid the Poisson’s locking, an exact description of elastic forces is presented by Sopanen and Mikkola [21], but the simplest way is setting the Poisson ratio to zero directly. Possible alternatives to solve other locking problems are selective reduced integration [22–24] and the redefinition of elastic forces based on the Hellinger-Reissner principle [20, 25].