scholarly journals A New Concept Compliant Platform with Spatial Mobility and Remote Actuation

2019 ◽  
Vol 9 (19) ◽  
pp. 3966 ◽  
Author(s):  
Nicola Pio Belfiore
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Rigid Body ◽  
Mode Analysis ◽  
Spatial Mobility ◽  
Element Analysis ◽  
Remote Actuation ◽  
Elastic Joints ◽  
Monolithic Structure ◽  
Surgical Operations

This paper presents a new tendon-driven platform with spatial mobility. The system can be obtained as a monolithic structure, and its motion is based on the concept of selective compliance. The latter contributes also to optimizing the use of the material by avoiding parasitic deformations. The presented platform makes use of lumped compliance with three different kinds of elastic joints. An analysis of the platform mobility based on finite element analysis is provided together with an assembly mode analysis of the equivalent pseudo-rigid body mechanism. Surgical operations in laparoscopic environments are the natural fields of applications for this device.

Finite Element Analysis of a Steel Spiral Staircase with Multiple Supports

2011 ◽  
Vol 255-260 ◽  
pp. 1964-1967
Author(s):  
Tao Chen ◽  
Hua Dong He
Keyword(s):  
Finite Element Method ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Mode Analysis ◽  
Complex Geometries ◽  
Finite Element Analyses ◽  
Element Analysis ◽  
Linear Elastic ◽  
Moment Distribution ◽  
Spiral Staircase

This paper presents finite element analyses of a steel spiral staircase with multiple supports. The complex geometries were modeled using commercial finite element method (FEM) software. Linear elastic analyses were carried out to investigate its deformation and moment distribution. Besides these, mode analysis was also performed to explore its pedestrian comfort. Finally the reliability of the structure is proved.

The Stiffness Model of Leaf-Type Isosceles-Trapezoidal Flexural Pivots

2008 ◽  
Vol 130 (8) ◽  
Author(s):  
Pei Xu ◽  
Yu Jingjun ◽  
Zong Guanghua ◽  
Bi Shusheng
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Rigid Body ◽  
Compliant Mechanisms ◽  
Nonlinear Finite Element Analysis ◽  
Nonlinear Finite Element ◽  
Leaf Segment ◽  
Element Analysis ◽  
Leaf Type ◽  
Stiffness Model

A leaf-type isosceles-trapezoidal flexural pivot can be of great practical use for designing compliant mechanisms. The analysis of load-deflection behavior for such a pivot is essential to the study of the mechanisms that are comprised of them. Based on the analysis of a single special loaded leaf segment, a pseudo-rigid-body four-bar model is proposed. The four-bar model is further simplified to a pin-joint model for some simple applications. The accuracy of both models is demonstrated by comparing results to those of nonlinear finite element analysis. At last, the two models are applied to analyze the cartwheel hinge as an example.

A Family of Butterfly Flexural Joints: Q-LITF Pivots

2011 ◽  
Author(s):  
Xu Pei ◽  
Jingjun Yu ◽  
Shusheng Bi ◽  
Guanghua Zong
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Rigid Body ◽  
Rigid Bodies ◽  
The Other ◽  
Element Analysis ◽  
Leaf Type ◽  
Center Shift ◽  
Body Model ◽  
Rigid Body Model

The Leaf-type Isosceles-Trapezoidal Flexural (LITF) pivot consists of two compliant beams and two rigid-bodies. For a single LITF pivot, the range of motion is small while the center-shift is relatively large. The capability of performance can be improved greatly by the combination of four LITF pivots. Base on the pseudo-rigid-body model (PRBM) of a LITF pivot, a method to construct the Quadri-LITF pivots is presented by regarding a single LITF pivot (or double-LITF pivot) as a the configurable flexure module. Ten types of Q-LITF pivots are synthesized. Compared with the single LIFT pivot, the stroke becomes larger, and stiffness becomes smaller. Four of them have the increased center-shift. The other four have the decreased center-shift. One of the quadruple LITF pivots is selected as the examples to explain the proposed method. The comparison between PRBM and Finite Element Analysis (FEA) result shows the validity and effectiveness of the method.

Design of a 3-DOF Compliant Parallel Mechanism for Displacement Amplification

2013 ◽  
Author(s):  
Qiang Zeng ◽  
Kornel F. Ehmann
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Heat Balance ◽  
Parallel Mechanism ◽  
Compliant Mechanism ◽  
Element Analysis ◽  
Resonant Frequencies ◽  
Compact Size ◽  
Compliant Parallel Mechanism ◽  
Monolithic Structure

Prevalent general design methods and applications of compliant displacement amplifiers are focused on 1-DOF units composed into serial structures, which are limited by their output motions, stiffness, heat balance, repeatability and resonant frequencies. To improve the output properties of compliant displacement amplifiers, a monolithic structure is presented in the form of a compliant parallel mechanism. In the proposed moving structure, the compliant mechanism of the displacement amplifier is designed with 3-DOF to generate uniformly magnified output properties in all directions. High first resonant frequencies and amplification ratios are achieved in a compact size compared to existing compliant displacement amplifiers. The related kinematics, amplification ratios and resonant frequencies of the amplifier are analytically modeled, and the results are simulated by finite-element analysis. The proposed design is employable for micro/nano positioning stages operating within a prismatic output workspace.

scholarly journals Novel compliant wiper mechanism

2018 ◽  
Vol 9 (2) ◽  
pp. 327-336
Author(s):  
Raşit Karakuş ◽  
Engin Tanık
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Rigid Body ◽  
Fundamental Concept ◽  
Element Analysis ◽  
Analytical Results

Abstract. Conventional wiper mechanisms that are used in automotive vehicles comprise numerous linkages and joints. In this study, in order to obtain a simpler design, a novel compliant wiper mechanism is introduced. The wiper mechanism is essentially a partially compliant four-bar mechanism. To the best of our knowledge, this is the first compliant wiper mechanism in the literature. The wipers currently labeled “compliant” in the literature possess only a flexible wiper blade frame. However, these are still driven by conventional rigid body mechanisms. After introduction of the fundamental concept, a compliant wiper mechanism is designed for an L7e car. Finite element analysis is carried out for verifying analytical results and fatigue calculations are performed. Finally, a prototype is manufactured, and it is experimentally verified that a compliant wiper mechanism may have an infinite life.

Spatial-Beam Large-Deflection Equations and Pseudo-Rigid-Body Model for Axisymmetric Cantilever Beams

2011 ◽  
Author(s):  
Issa A. Ramirez ◽  
Craig P. Lusk
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Rigid Body ◽  
Three Dimensional ◽  
Vertical Axis ◽  
Analysis Model ◽  
Element Analysis ◽  
Body Model ◽  
Straight Beam ◽  
Rigid Body Model

The kinematic equations for approximating the deflection of a three-dimensional cantilever beam were developed. The numerical equations were validated with a Finite Element Analysis program. With these equations, a pseudo-rigid-body model (PRBM) for an axisymmetric straight beam was developed. The axisymmetric PRBM consists of a spherical joint connecting two rigid links. The location of the deformed end of the beam is determined by two angles and the characteristic radius factor. The angle of the beam with respect to the vertical axis depends on the direction of the force with respect to the undeformed coordinate system. The Pearson’s correlation coefficient for the Finite Element Analysis model and the numerical integration is 0.952.

scholarly journals Multistable Shape-Shifting Surfaces

2012 ◽  
Author(s):  
Paul Montalbano ◽  
Craig Lusk
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Rigid Body ◽  
Unit Cell ◽  
Physical Barrier ◽  
Element Analysis ◽  
Out Of Plane ◽  
Unit Cells ◽  
Planar Shapes ◽  
Deformable Walls

This paper presents designs for Multistable Shape-Shifting Surfaces (MSSS) by introducing bistability into the Shape-Shifting Surface (SSS). SSSs are defined as surfaces that retain their effectiveness as a physical barrier while undergoing changes in shape. The addition of bistability to the SSS gives the surface multiple distinct positions in which it remains when shifted to, i.e. by designing bistability into a single SSS link, the SSS unit cell can change into multiple shapes, and stabilize within the resulting shape, while maintaining integrity against various forms of external assaults normal to its surface. Planar stable configurations of the unit cell include, expanded, compressed, sheared, half-compressed, and partially-compressed, resulting in the planar shapes of a large square, small square, rhombus, rectangle, and trapezoid respectively. Tiling methods were introduced which gave the ability to produce out-of-plane assemblies using planar MSSS unit cells. Applications for MSSSs include size-changing vehicle beds, expandable laptop screens, deformable walls, and volume-changing rigid-storage containers. Analysis of the MSSS was done using Pseudo-rigid-Body Models (PRBMs) and Finite Element Analysis (FEA) which ensured bistable characteristics before prototypes were fabricated.

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