Development of an actuated corrugated laminate for morphing structures

2020 ◽  
Vol 125 (1283) ◽  
pp. 180-204
Author(s):  
A. Airoldi ◽  
D. Rigamonti ◽  
G. Sala ◽  
P. Bettini ◽  
E. Villa ◽  
...  
Keyword(s):  
Finite Element ◽  
Shape Memory Alloy ◽  
System Performance ◽  
Strength Properties ◽  
Finite Element Analyses ◽  
Composite Part ◽  
Experimental Assessment ◽  
Sma Actuators ◽  
Actuation System ◽  
Numerical Approaches

ABSTRACTThis paper presents the design, manufacturing and experimental assessment of a morphing element consisting of a composite corrugated panel that hosts a diffused actuation system based on Shape Memory Alloy (SMA) actuators. The characterisation of the SMA actuators is reported and the system performance is predicted through an analytical model and finite element analyses. Two versions of the actuated system are proposed, with different methods for the physical integration of the SMA wires into the composite part. Manufacturing and testing of specimens with different wire densities are reported. Correlation with experiments validates the analytical and numerical approaches adopted for the design and analyses. The results confirm the potential of the concept proposed for developing corrugated panels that can be contracted in a predefined direction by a load-bearing actuation system, but still retain high stiffness and strength properties in other directions.

3D Manipulation of an Active Steerable Needle via Actuation of Multiple SMA Wires

Robotica ◽  
2019 ◽  
Vol 38 (3) ◽  
pp. 410-426 ◽  
Author(s):  
Bardia Konh ◽  
Dayne Sasaki ◽  
Tarun K. Podder ◽  
Hashem Ashrafiuon
Keyword(s):  
Finite Element ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Medical Procedures ◽  
Finite Element Analyses ◽  
Sma Actuators ◽  
3D Space ◽  
3D Manipulation ◽  
Multiple Actuators ◽  
Steerable Needle

SummaryMany medical procedures such as brachytherapy, thermal ablations, and biopsies are performed using needle-based procedures. In this work, 3D manipulation of an active needle realized by multiple Shape Memory Alloy (SMA) actuators was first predicted by Finite Element Analyses (FEA), and then demonstrated by a fabricate prototype. The FEA results were validated by planar deflection of an active needle. A similar FEA was developed to predict 3D manipulation of the active needle. For 17-gage needle, a maximum of 26° reversible deflection was achieved in 3D space via actuation forces of a 0.127 mm SMA wire. A scaled prototype was also developed and tested to show the feasibility of developing a 3D steering active needle with multiple actuators.

Finite Element Modeling of Steel Pipeline Reconstruction Using Fiberglass Composite Material

2015 ◽  
Vol 725-726 ◽  
pp. 648-653 ◽  
Author(s):  
Ekaterina A. Nekliudova ◽  
Artem S. Semenov ◽  
S.G. Semenov ◽  
Boris E. Melnikov
Keyword(s):  
Finite Element ◽  
Composite Material ◽  
Stress State ◽  
Elastic Moduli ◽  
Strength Properties ◽  
Geometrical Parameters ◽  
Effective Elastic Moduli ◽  
Composite Part ◽  
Steel Pipeline ◽  
Fiberglass Composite

A stress state of the partially damaged underground steel pipeline after reconstruction by means of the fiberglass composite material is considered. The strength properties of the composite are determined experimentally. The effective elastic moduli of the composite are determined by means of the finite element homogenization. Tsai-Wu failure criterion is used for the composite part of the pipeline. The influence of geometrical parameters and loading conditions on the safety factor of the pipeline is analyzed and discussed.

scholarly journals Stiffness Estimation and Equivalence of Boundary Conditions in FEM Models

2021 ◽  
Vol 11 (4) ◽  
pp. 1482
Author(s):  
Róbert Huňady ◽  
Pavol Lengvarský ◽  
Peter Pavelka ◽  
Adam Kaľavský ◽  
Jakub Mlotek
Keyword(s):  
Boundary Condition ◽  
Finite Element ◽  
Boundary Conditions ◽  
Model Updating ◽  
Element Model ◽  
Computational Time ◽  
Stiffness Coefficients ◽  
First Case ◽  
Numerical Approaches

The paper deals with methods of equivalence of boundary conditions in finite element models that are based on finite element model updating technique. The proposed methods are based on the determination of the stiffness parameters in the section plate or region, where the boundary condition or the removed part of the model is replaced by the bushing connector. Two methods for determining its elastic properties are described. In the first case, the stiffness coefficients are determined by a series of static finite element analyses that are used to obtain the response of the removed part to the six basic types of loads. The second method is a combination of experimental and numerical approaches. The natural frequencies obtained by the measurement are used in finite element (FE) optimization, in which the response of the model is tuned by changing the stiffness coefficients of the bushing. Both methods provide a good estimate of the stiffness at the region where the model is replaced by an equivalent boundary condition. This increases the accuracy of the numerical model and also saves computational time and capacity due to element reduction.

Design of flexure revolute joint based on compliance and stiffness ellipsoids

2021 ◽  
pp. 095441002110169
Author(s):  
Jing Zhang ◽  
Hong-wei Guo ◽  
Juan Wu ◽  
Zi-ming Kou ◽  
Anders Eriksson
Keyword(s):  
Finite Element ◽  
Single Point ◽  
Synthesis Method ◽  
Nonlinear Finite Element ◽  
Finite Element Analyses ◽  
Rotational Stiffness ◽  
Rotational Angle ◽  
Parameterized Model ◽  
Flexure Joints ◽  
Translational Stiffness

In view of the problems of low accuracy, small rotational angle, and large impact caused by flexure joints during the deployment process, an integrated flexure revolute (FR) joint for folding mechanisms was designed. The design was based on the method of compliance and stiffness ellipsoids, using a compliant dyad building block as its flexible unit. Using the single-point synthesis method, the parameterized model of the flexible unit was established to achieve a reasonable allocation of flexibility in different directions. Based on the single-parameter error analysis, two error models were established to evaluate the designed flexure joint. The rotational stiffness, the translational stiffness, and the maximum rotational angle of the joints were analyzed by nonlinear finite element analyses. The rotational angle of one joint can reach 25.5° in one direction. The rotational angle of the series FR joint can achieve 50° in one direction. Experiments on single and series flexure joints were carried out to verify the correctness of the design and analysis of the flexure joint.

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