The Modeling of Leaf-Type Isosceles-Trapezoidal Flexural Pivots

2007 ◽  
Author(s):  
Xu Pei ◽  
Jingjun Yu ◽  
Guanghua Zong ◽  
Shusheng Bi
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Compliant Mechanisms ◽  
Accurate Method ◽  
Leaf Segment ◽  
Element Analysis ◽  
Leaf Type ◽  
Linear Finite Element ◽  
Body Model ◽  
Rigid Body Model

A Leaf-type Isosceles-trapezoidal Flexural (LITF) 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 on the mechanisms which are composed of the pivots. A pseudo-rigid-body model provides a simple and accurate method. Based on the analysis of a single special loaded leaf segment, a four-bar model is presented. The four-bar model is further simplified to a pin-joint model for the simpler applications. The accuracy of both models is demonstrated by comparing results to those of non-linear finite element analysis. At last, the two models are applied to analyze the cartwheel hinge as an example.

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 Single-Acting Constant-Force Actuator Based on Dielectric Elastomers

2008 ◽  
Author(s):  
Giovanni Berselli ◽  
Rocco Vertechy ◽  
Gabriele Vassura ◽  
Vincenzo Parenti Castelli
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Compliant Mechanism ◽  
Structural Parameters ◽  
Dielectric Elastomer ◽  
Constant Force ◽  
Element Analysis ◽  
Body Model ◽  
Rigid Body Model ◽  
Supporting Frame

The interest in actuators based on dielectric elastomer films as a promising technology in robotic and mechatronic applications is increasing. The overall actuator performances are influenced by the design of both the active film and the film supporting frame. This paper presents a single-acting actuator which is capable of supplying a constant force over a given range of motion. The actuator is obtained by coupling a rectangular film of silicone dielectric elastomer with a monolithic frame designed to suitably modify the force generated by the dielectric elastomer film. The frame is a fully compliant mechanism whose main structural parameters are calculated using a pseudo-rigid-body model and then verified by finite element analysis. Simulations show promising performance of the proposed actuator.

Design of a Single-Acting Constant-Force Actuator Based on Dielectric Elastomers

2009 ◽  
Vol 1 (3) ◽  
Author(s):  
Giovanni Berselli ◽  
Rocco Vertechy ◽  
Gabriele Vassura ◽  
Vincenzo Parenti Castelli
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Compliant Mechanism ◽  
Structural Parameters ◽  
Dielectric Elastomer ◽  
Constant Force ◽  
Element Analysis ◽  
Body Model ◽  
Rigid Body Model ◽  
Supporting Frame

The interest in actuators based on dielectric elastomer films as a promising technology in robotic and mechatronic applications is increasing. The overall actuator performances are influenced by the design of both the active film and the film supporting frame. This paper presents a single-acting actuator, which is capable of supplying a constant force over a given range of motion. The actuator is obtained by coupling a rectangular film of silicone dielectric elastomer with a monolithic frame designed to suitably modify the force generated by the dielectric elastomer film. The frame is a fully compliant mechanism whose main structural parameters are calculated using a pseudo-rigid-body model and then verified by finite element analysis. Simulations show promising performance of the proposed actuator.

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.

A Pseudo-Rigid Body Model for Compliant Edge Panels in Origami-Inspired Mechanisms

2016 ◽  
Author(s):  
Alden Yellowhorse ◽  
Larry L. Howell
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Rigid Body ◽  
Element Analysis ◽  
Design Problems ◽  
Body Model ◽  
Rigid Body Model ◽  
Potential Applications

Origami-inspired mechanisms have a variety of potential applications but present many challenges in their design. Problems such as mechanism inflexibility must be considered for any application but may not always be easily resolvable. One option in such a case would be to rely on the inherent flexibility of the origami panels to permit motion. This paper presents a method for increasing the flexibility of a structure and enabling motion in an otherwise immobile origami-inspired mechanism. This method will be derived analytically and then verified through finite-element analysis and experiments.

Bistable Compliant Four-Bar Mechanisms With a Single Torsional Spring

2006 ◽  
Author(s):  
Adarsh Mavanthoor ◽  
Ashok Midha
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Mechanism Design ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Stored Energy ◽  
Element Analysis ◽  
Bistable Behavior ◽  
Torsional Spring ◽  
Bistable Mechanism

Significant reduction in cost and time of bistable mechanism design can be achieved by understanding their bistable behavior. This paper presents bistable compliant mechanisms whose pseudo-rigid-body models (PRBM) are four-bar mechanisms with a torsional spring. Stable and unstable equilibrium positions are calculated for such four-bar mechanisms, defining their bistable behavior for all possible permutations of torsional spring locations. Finite Element Analysis (FEA) and simulation is used to illustrate the bistable behavior of a compliant mechanism with a straight compliant member, using stored energy plots. These results, along with the four-bar and the compliant mechanism information, can then be used to design a bistable compliant mechanism to meet specified requirements.

Specimen positioning effect on microshear test: Non-linear finite element analysis

2012 ◽  
Vol 28 ◽  
pp. e15-e16
Author(s):  
L.H.A. Raposo ◽  
L.C.M. Dantas ◽  
T.A. Xavier ◽  
A.G. Pereira ◽  
A. Versluis ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Element Analysis ◽  
Linear Finite Element ◽  
Non Linear
Sign in / Sign up

Export Citation Format

Share Document