scholarly journals Improvement of a Tunable Stiffness Organ-Grasping Device by Design of a Wavy-Shaped Beam Structure

2021 ◽  
Vol 11 (10) ◽  
pp. 4581
Author(s):  
Toshihiro Kawase ◽  
Takaaki Sugino ◽  
Shinya Onogi ◽  
Kenji Kawashima ◽  
Yoshikazu Nakajima
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Liver Resection ◽  
Beam Structure ◽  
Wavy Structure ◽  
Liver Surface ◽  
Low Stiffness ◽  
High Flexibility ◽  
The Waves ◽  
Tunable Stiffness

Tunable stiffness mechanisms can increase the noninvasiveness and stability of organ manipulation in laparoscopic liver resection. We have developed an organ-grasping device using beam-shaped tunable stiffness mechanism. Increasing the change ratio of stiffness will improve the performance of the device by offering high flexibility when adhering to the liver surface and high rigidity during the manipulation of the liver; however, optimal design of the beam has not been investigated. In this study, we investigate the wavy structure shape of the device that enhances the change in the ratio of stiffness. To increase the stiffness in a high-stiffness state, we used principal stress lines in the device to design the edge curve of the wavy shape material in the beams. We also investigated the arrangement of the wavy shape to decrease the stiffness in a low-stiffness state. Simulation using finite element method showed that the change ratio of stiffness was improved up to 13.0 by the new wavy shape arranged with the uniformly thick bottom of the waves.

An efficient semi-analytical static and free vibration analysis of laminated and sandwich beams based on linear elasticity theory

2021 ◽  
pp. 030932472110626
Author(s):  
Zhao Yin ◽  
Hangduo Gao ◽  
Gao Lin
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Free Vibration ◽  
Mechanical Load ◽  
Geometric Model ◽  
Free Vibration Analysis ◽  
Sandwich Beams ◽  
Beam Structure ◽  
Precise Integration ◽  
Element Method

Based on the two-dimensional (2D) elastic theory without enforcing any beam assumption, an efficient semi-analytical scaled boundary finite element method (SBFEM) is proposed to solve the bending and free vibration responses of composite laminated and sandwich beams under the mechanical load. The scaled center is placed at infinity, which produces the accurate result by discretizing only the longitudinal direction of the beam structure treated as a one-dimensional (1D) discretization problem. A new kind of 1D high-order spectral element shape functions with the advantages of high accuracy and superior convergence is introduced in SBFEM coordinate system to approximate the geometric model and corresponding variables. The principle of weighted residual in conjunction with the Green’s theorem are applied to obtain the SBFEM governing equation of each layer with respect to radial displacement fields. The solution of equation is indicated analytically by a matrix exponential function, which can be accurately solved by using the precise integration technique (PIT). Finally, an effective and simple stiffness matrix is obtained. By comparing two examples with the solutions based on the finite element method (FEM), the results show that the proposed method has good accuracy and rapid convergence with only a few meshes. The numerical examples are given to investigate the parametric effects of the stacking sequence, thickness ratio, boundary condition, and load form on the variation of the displacement, stress and natural frequency. The results validate that the present technique is also applicable to the complex beam structure with softcore layer inside.

The Study of Elastic Strains of Parts from the Grinding Technological System

2013 ◽  
Vol 371 ◽  
pp. 101-105
Author(s):  
Maxim Casian
Keyword(s):  
Numerical Simulation ◽  
Finite Element Method ◽  
Finite Element ◽  
Technological System ◽  
Gear Grinding ◽  
Low Stiffness ◽  
Rotational Direction ◽  
Grinding System ◽  
Elastic Strains ◽  
Element Method

In this paper we present the results of numerical simulation of the stiffness of gear grinding system using finite element method (FEM). Since the rigidity of system can be characterized by two aspects, one static and one dynamic. We will concentrate on the low stiffness of components inside the system to find errors that may affect the precision on the horizontal, vertical and rotational direction of technological system elements.

Research on Machining Accuracy in Milling Ti6Al4V Thin-Walled Component with Paraffin Reinforcement

2012 ◽  
Vol 268-270 ◽  
pp. 504-509
Author(s):  
Biao Gao ◽  
Jie Sun ◽  
Jian Feng Li
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Machining Accuracy ◽  
The Finite Element Method ◽  
Technical Problems ◽  
Low Stiffness ◽  
Thin Walled ◽  
Element Method

According to the technical problems such as low stiffness vibration and dimension error in milling Ti6Al4V thin-walled component, the manufacturing with paraffin reinforcement is studied. Firstly, paraffin formula for milling thin-walled component is researched. Secondly, applying the finite element method (FEM) to predict the deformation of machining with paraffin reinforcement and the corresponding milling experiments is done to check the the validity of the model. Finally, the influences of machining accuracy about different paraffin formulas for the same component are obtained. This study supplies support for the research of paraffin formula which are based on reducing the distortion of workpiece.

Coupled Axial-Lateral Dynamic Analysis Using 3-D Riccati-Finite Element Method

1991 ◽  
Author(s):  
Rajagopal Subbiah
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Degrees Of Freedom ◽  
Iterative Technique ◽  
Beam Structure ◽  
Dynamical Characteristics ◽  
Structural Problems ◽  
Rotating Systems ◽  
Algorithmic Procedure ◽  
Element Method

Abstract An improved algorithmic procedure is discussed to obtain the dynamical characteristics of rotating systems applicable to both 2-D and 3-D models. The beam structure has been modeled in 3 dimension representing five degrees of freedom at each node (three translations and two rotations) using the Riccatifinite element method and solved by an iterative technique. This method provides another convenient way of solving a variety of rotating structural problems using personal computers.

The Application of Dynamic Finite Element Method in Beam Structure

2010 ◽  
Vol 129-131 ◽  
pp. 104-108
Author(s):  
Li Cheng Yang ◽  
Shang Le Qing ◽  
Xuan Huang ◽  
Yi Ping Luo
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Dynamic Problem ◽  
Good Method ◽  
Large Error ◽  
Beam Structure ◽  
Basic Principles ◽  
Dynamic Finite Element ◽  
Calculation Results ◽  
Element Method

When the practical problem is solved based on finite element method, researchers are often transformed dynamic problem into static one in order to simplify calculation, which brings to large error generally. FEM is good method in solving dynamic characteristics of structure by using only drawings, project and related experienced knowledge. By analyzing the similarities and differences between static FEM and dynamic FEM and discussing their basic principles, the calculation results of static and dynamic FEM are discussed according to the example of simply supported beam with simple harmonic excited force in its midpoint position. The results show that dynamic finite element method has higher solution precise than static one in dealing with practical dynamic problem.

scholarly journals Design and simulation of an optimized electrothermal microactuator with Z-shaped beams

2015 ◽  
Vol 25 (3) ◽  
pp. 19-24
Author(s):  
Margarita Tecpoyotl Torres ◽  
Ramón Cabello Ruiz ◽  
José Gerardo Vera Dimas
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Electric Potential ◽  
Solid Modeling ◽  
Output Force ◽  
Load Sensor ◽  
Low Stiffness ◽  
3D Software ◽  
Determinant Factor ◽  
Element Method

The displacement of the central shuttle of a Z-shape chevron actuator can be calculated using a developed approach from other authors. Who demonstrated that the actuators with this geometry offer a larger displacement compared with V-shape actuators. Z-shape offers a larger stiffness and output force for the case of only one arm.  This paper is focused on the optimization of the Z-shaped beams of a chevron actuator of eight beams, which seeks to increase the previously described response. The structure is designed in parametric solid modeling 3D software Autodesk Inventor, and simulated by finite element method in Ansys 15.0. These simulations were implemented considering several modifications on the length of the Z-shaped beams in order to choose the most appropriate length. The electric potential applied in all cases was from 0.2 V up to 5 V. The Z-shape length of the arms for the case of the optimized Z-shape actuator increases the shuttle’s displacement in approximately 50% compared to V-shape actuator, and 38% compare to the original Z-shape. Analytical adjusted approach is extremely matched with the simulations results. Length of the Z-shape beam is the determinant factor of the displacement. The low stiffness of the optimized Z-shape actuator (89% lower than the original V-shape and 58% compared to Z-shape) can allow its use as load sensor. 

Simulation of tuning graphene plasmonic behaviors by ferroelectric domains for self-driven infrared photodetector applications

Nanoscale ◽  
2019 ◽  
Vol 11 (43) ◽  
pp. 20868-20875 ◽  
Author(s):  
Junxiong Guo ◽  
Yu Liu ◽  
Yuan Lin ◽  
Yu Tian ◽  
Jinxing Zhang ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Interfacial Effect ◽  
Infrared Photodetector ◽  
The Finite Element Method ◽  
Ferroelectric Domains ◽  
Element Method

We propose a graphene plasmonic infrared photodetector tuned by ferroelectric domains and investigate the interfacial effect using the finite element method.

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