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19 pages, 18326 KiB

Open AccessArticle

Geometric Design Methodology for Deployable Self-Locking Semicylindrical Structures

by Zhanwei Zhao and Lei Yu

Buildings 2024, 14(6), 1690; https://doi.org/10.3390/buildings14061690 - 6 Jun 2024

Cited by 1 | Viewed by 1264

Due to their unique bistable characteristics, deployable self-locking structures are suitable for many engineering fields. Without changing the geometrical composition, such structures can be unfolded and locked solely by the elastic deformation of materials. However, their further applications are hampered by the lack of simple and systematic geometric design methodologies that consider arbitrary structural curvature profiles. This paper proposes such a methodology for double-layer semicylindrical grid structures to simplify their cumbersome geometric design. The proposed methodology takes joint sizes into account to ensure that the design results can be applied to actual projects without further adjustments. By introducing symmetry into the structural units (SUs) and selecting reasonable geometric parameters that describe the structural side elevation profile, a concise set of simultaneous nonlinear geometric constraint equations is established, the solution of which provides the geometric parameter values of the grid shape. On this basis, the remaining geometric parameter values, i.e., the geometric parameter values of the inner scissor-like elements (SLEs) of each SU, can be achieved from the equations derived from general SLEs. Design examples and the assembled physical grid structure indicate the feasibility and wide applicability of the proposed geometric design methodology. Full article

(This article belongs to the Section Building Structures)

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19 pages, 6717 KiB

Open AccessArticle

Analysis and Structure Optimization of Scissor-Type Micro-Stirrer with the Most Effective Output Performance for Thrombus Dissolution in Interventional Therapy

by Jingjing Yang, Benyang Rong, Lei Wang, Minoru Morita, Guifang Deng, Yifan Jiang and Junbing Qian

Actuators 2023, 12(2), 60; https://doi.org/10.3390/act12020060 - 30 Jan 2023

Cited by 1 | Viewed by 1790

Abstract

Compared with thrombus dissolution using only thrombolytic agents, an advanced therapy of direct stirring of the blood clot can yield shorter recanalization time and higher recanalization velocity. Our previous research presented the design of a novel micro-stirrer, which can convert longitudinal vibration into transverse vibration and eventually generate opposite transverse vibration at the end-effort, like a scissor, for efficient blood clot stirring and thrombus dissolution acceleration. Transverse vibration is the most effective movement to dissolve thrombi. However, the small size of blood vessels has strict limits, which will greatly affect the output transverse vibration. Therefore, to improve the output performance of the micro-stirrer in curved and narrow vascular spaces, the analysis and structure optimization of the micro-stirrer is expected to increase the vibration mode conversion efficiency from longitudinal to transverse mode. The design concept and theoretical analysis of the micro-stirrer are presented in detail. Aiming to obtain the optimal structure parameters of the micro-stirrer, the mathematical model is established and analyzed. Next, a series of finite element models involving important structure parameters are designed and investigated. Finally, the optimal structure parameters are obtained, and the stirring effect in a blood vessel is verified by simulation and experiment. Full article

(This article belongs to the Section Actuators for Medical Instruments)

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20 pages, 2730 KiB

Open AccessArticle

Synthesis, Analysis, and Design of a Novel Mechanism for the Trailing Edge of a Morphing Wing

by Harun Levent Şahin and Yavuz Yaman

Aerospace 2018, 5(4), 127; https://doi.org/10.3390/aerospace5040127 - 11 Dec 2018

Cited by 7 | Viewed by 9719

Abstract

In the design and analysis of morphing wings, several sciences need to be integrated. This article tries to answer the question, “What is the most appropriate actuation mechanism to morph the wing profile?” by introducing the synthesis, analysis, and design of a novel scissor-structural mechanism (SSM) for the trailing edge of a morphing wing. The SSM, which is deployable, is created via a combination of various scissor-like elements (SLEs). In order to provide mobility requirements, a four-bar linkage (FBL) is assembled with the proposed SSM. The SSM is designed with a novel kinematic synthesis concept, so it follows the airfoil camber with minimum design error. In this concept, assuming a fully-compliant wing skin, various types of SLEs are assembled together, and emergent SSM provide the desired airfoil geometries. In order to provide the required aerodynamic efficiency of newly-created airfoil geometries and obtain pressure distribution over the airfoil, two-dimensional (2D) aerodynamic analyses have been conducted. The analyses show similar aerodynamic behavior with the desired NACA airfoils. By assigning the approximate link masses and mass centers, the dynamic force analysis of the mechanism has also been performed, and the required torque to drive the newly-developed SSM is estimated as feasible. Full article

(This article belongs to the Special Issue 8th EASN-CEAS Workshop on Manufacturing for Growth and Innovation)

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