Nonlinear modeling and analysis of compliant mechanisms with circular flexure hinges based on quadrature beam elements

2018 ◽  
Vol 233 (9) ◽  
pp. 3277-3285 ◽  
Author(s):  
SiQiang Xu ◽  
XiaoBo Zhu ◽  
ZeGuang Dong ◽  
PinKuan Liu
Keyword(s):  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Beam Element ◽  
System Level ◽  
Weighting Coefficient ◽  
Flexure Hinge ◽  
Tangent Stiffness Matrix ◽  
Flexure Hinges ◽  
Geometrically Exact Beam ◽  
Bridge Type

Linear modeling approaches for compliant mechanisms attract significant attention. However, geometrical nonlinearities require consideration generally because they may result in the modeling error. This paper presents a nonlinear quadrature beam element modeling approach for compliant mechanisms. The geometrically exact beam theory is employed as the basis for the element. Meanwhile, the element tangent stiffness matrix is obtained by using the weak form quadrature element method, which does not need shape functions any more and only performs simple algebraic operations of weighting coefficient matrices. One quadrature beam element is needed to model a flexure hinge. For validating the effectiveness of the proposed approach, typical circular flexure hinges are employed. Moreover, a typical bridge-type compliant mechanism is studied by the proposed approach. Finally, the efficiency and accuracy of the proposed approach are verified by comparing with the finite element results. Meanwhile, the results show that the shear effect can be ignored, when a single flexure hinge is investigated. Nevertheless, the nonlinear behavior of compliant mechanisms is affected at the system level. In addition, the magnification ratio of a bridge-type compliant mechanism is related to the width and material of the structure when nonlinearity is considered.

Hybrid Compliant Mechanism Design Using a Mixed Mesh of Flexure Hinge Elements and Beam Elements Through Topology Optimization

2015 ◽  
Vol 137 (9) ◽  
Author(s):  
Lin Cao ◽  
Allan T. Dolovich ◽  
Wenjun (Chris) Zhang
Keyword(s):  
Topology Optimization ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Optimization Technique ◽  
Flexure Hinge ◽  
Beam Elements ◽  
Flexure Hinges ◽  
New Type ◽  
Meshing Scheme ◽  
Compliant Mechanism Design

This paper proposes a topology optimization framework to design compliant mechanisms with a mixed mesh of both beams and flexure hinges for the design domain. Further, a new type of finite element, i.e., super flexure hinge element, was developed to model flexure hinges. Then, an investigation into the effects of the location and size of a flexure hinge in a compliant lever explains why the point-flexure problem often occurs in the resulting design via topology optimization. Two design examples were presented to verify the proposed technique. The effects of link widths and hinge radii were also investigated. The results demonstrated that the proposed meshing scheme and topology optimization technique facilitate the rational decision on the locations and sizes of beams and flexure hinges in compliant mechanisms.

Design of Circular Cross-Section Corner-Filleted Flexure Hinges for Three-Dimensional Compliant Mechanisms

2002 ◽  
Vol 124 (3) ◽  
pp. 479-484 ◽  
Author(s):  
Nicolae Lobontiu ◽  
Jeffrey S. N. Paine
Keyword(s):  
Cross Section ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Three Dimensional ◽  
Circular Cross Section ◽  
Axial Loading ◽  
Flexure Hinge ◽  
Flexure Hinges ◽  
Element Simulation ◽  
The Right

The paper introduces the circular cross-section corner-filleted flexure hinges as connectors in three-dimensional compliant mechanism applications. Compliance factors are derived analytically for bending, axial loading and torsion. A circular cross-section corner-filleted flexure hinge belongs to a domain delimited by the cylinder (no fillet) and the right circular cross-section flexure hinge (maximum fillet radius). The analytical model predictions are confirmed by finite element simulation and experimental measurements. The circular cross-section corner-filleted flexure hinges are characterized in terms of their compliance, precision of rotation and stress levels.

Dynamics of a compliant mechanism based on flexure hinges

2005 ◽  
Vol 219 (2) ◽  
pp. 225-235 ◽  
Author(s):  
K-B Choi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Compliant Mechanism ◽  
Equation Of Motion ◽  
Rigid Bodies ◽  
Flexure Hinge ◽  
Flexure Hinges ◽  
Better Than ◽  
Element Method

This paper presents a novel equation of motion for flexure hinge-based mechanisms. The conventional equation of motion presented in previous work does not adequately describe the behaviours of rigid bodies for the following reasons: firstly, rotational directions for a transformed stiffness lack consistency at the two ends of a flexure hinge; secondly, the length of the flexure hinge is not considered in the equation. The equation of motion proposed in this study solves these problems. Modal analyses are carried out using the proposed equation of motion, the conventional equation of motion found in previous work, and a finite element method. The results show that the proposed equation of motion describes the behaviours of the rigid bodies better than the conventional equation of motion does.

scholarly journals Multi-objective optimization of a type of ellipse-parabola shaped superelastic flexure hinge

2016 ◽  
Vol 7 (1) ◽  
pp. 127-134 ◽  
Author(s):  
Zhijiang Du ◽  
Miao Yang ◽  
Wei Dong
Keyword(s):  
Compliant Mechanisms ◽  
Pareto Frontier ◽  
Flexure Hinge ◽  
Multi Objective Optimization ◽  
Nsga Ii ◽  
Element Analysis ◽  
Multi Objective ◽  
Flexure Hinges ◽  
Static Responses ◽  
Motion Range

Abstract. Flexure hinges made of superelastic materials is a promising candidate to enhance the movability of compliant mechanisms. In this paper, we focus on the multi-objective optimization of a type of ellipse-parabola shaped superelastic flexure hinge. The objective is to determine a set of optimal geometric parameters that maximizes the motion range and the relative compliance of the flexure hinge and minimizes the relative rotation error during the deformation as well. Firstly, the paper presents a new type of ellipse-parabola shaped flexure hinge which is constructed by an ellipse arc and a parabola curve. Then, the static responses of superelastic flexure hinges are solved via non-prismatic beam elements derived by the co-rotational approach. Finite element analysis (FEA) and experiment tests are performed to verify the modeling method. Finally, a multi-objective optimization is performed and the Pareto frontier is found via the NSGA-II algorithm.

scholarly journals Design, Modeling, and Analysis of a Novel Microgripper Based on Flexure Hinges

2014 ◽  
Vol 6 ◽  
pp. 947584 ◽  
Author(s):  
Zhigang Wu ◽  
Yangmin Li
Keyword(s):  
Maximum Stress ◽  
Fast Response ◽  
Flexure Hinge ◽  
Single Track ◽  
Ansys Software ◽  
End Effector ◽  
Modeling And Analysis ◽  
Flexure Hinges ◽  
Motion Range ◽  
Bridge Type

A new 2-DOF microgripper, which can perform the processing of the objects assembly and biological cells injection, is designed and modeled in this paper. The clamping action of the microgripper with the x direction is completed, however, when anything is clamped by the end effector, which can be completely driven by an actuator generated in y direction, at lastclamping and pushing motion are realized. The flexure hinge, which takes place of the conventional joint, is used as the translational and rotational hinges in the new structure. Otherwise, the whole microgripper is monolithic processing, which can efficiently overcome the disadvantages of the conventional hinge with friction, backlash, anderrors caused by the hinge assembly. Firstly, a kind of novel microgripper is designed in this paper, which can accomplish two-dimensional independent motions including a separate grip and single track push without interfering with each other. The bridge type amplifying structure with two-end output is adopted in the gripper to increase the motion range and the capacity of the microgripper. The piezoelectric actuator with fast response and high resolution is used as the drive element. Secondly, the geometrical and kinematical models are established and the formulas of the amplifying ratio, stiffness, maximum stress, and the natural frequency of this model are calculated, respectively. Finally, the FEM (finite element modeling) based on ANSYS software is built up to validate the formulas.

Design of Contact-aided Compliant Flexure Hinge Mechanism Using Superelastic Nitinol

2021 ◽  
pp. 1-19
Author(s):  
Zhongyuan Ping ◽  
Tianci Zhang ◽  
Chi Zhang ◽  
Jianbin Liu ◽  
Siyang Zuo
Keyword(s):  
Compliant Mechanism ◽  
Nickel Titanium ◽  
Flexure Hinge ◽  
Maximum Strain ◽  
Clinical Value ◽  
Element Analysis ◽  
Flexure Hinges ◽  
Static Models ◽  
Flexible Instruments ◽  
Bending Behaviour

Abstract This paper presents a novel miniature contact-aided compliant mechanism (CCM) that includes flexure hinges and contact-aided structures. This continuum mechanism comprises a nickel–titanium alloy (Nitinol) tube with CCM cut via laser micromachining and actuated using wires bending from −80° to +80° in four directions. The proposed CCM has the following merits: perfect capacity for deflection around the centroid, a self-backbone, and improved torsional as well as tensile strengths. Further, it is pre-assembled. First, kinematic and static models are used to predict the bending behaviour of the mechanism. Thereafter, the maximum strain is evaluated using finite element analysis (FEA) then compared with the static models. Finally, the performances of the mechanism are characterized by experiments. The results validate the proposed models and demonstrate that the torsional and tensile strengths of the proposed CCM increased by more than 100% and 30%, respectively, compared with those of conventional non-CCMs with a similar fatigue life. Moreover, with the integrated forceps and probe, the proposed mechanism can achieve object transfer and square trajectory scanning of the targeted location. These experimental results demonstrate the potential clinical value of the proposed mechanism and provide important insights into the design of long and flexible instruments for endoscopic surgery.

Modeling of a Symmetric Five-Bar Displacement Amplification Compliant Mechanism Using Energy Methods

2015 ◽  
Author(s):  
Moataz M. Elsisy ◽  
Yasser Anis ◽  
Mustafa Arafa ◽  
Chahinaz Saleh
Keyword(s):  
Vibration Amplitude ◽  
Energy Harvester ◽  
Compliant Mechanism ◽  
Mechanical Vibration ◽  
Element Model ◽  
Design Parameters ◽  
Flexure Hinge ◽  
Energy Methods ◽  
Flexure Hinges ◽  
The Right

We present a symmetric five-bar compliant mechanism for the displacement amplification of mechanical vibration. When the proposed mechanism is connected to an energy harvester, amplification of the input excitation vibration amplitude leads to an increase in the harvested power. Displacements in the compliant mechanism are caused by deflections in its flexure hinges. The flexure hinges we use are either of the right-circular, or the corner-filleted types. The mechanism is analyzed using energy methods. The displacement amplification was verified analytically and numerically using a finite element model. Through our model we present relations governing the displacement amplification in terms of the design parameters, such as the geometry of the mechanism, the flexure hinges dimensions, in addition to the load caused by the harvester. The effects of the flexure hinge dimensions on displacement amplification, are also presented.

Sign in / Sign up

Export Citation Format

Share Document