Optimization of Compliant Mechanisms by Use of Different Polynomial Flexure Hinge Contours

2019 ◽  
pp. 265-274 ◽  
Author(s):  
P. Gräser ◽  
S. Linß ◽  
L. Zentner ◽  
R. Theska
Keyword(s):  
Compliant Mechanisms ◽  
Flexure Hinge

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.

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.

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.

Design and Analysis of a Contact-Aided Variable Stiffness Flexure Hinge (CVSFH)

2021 ◽  
Author(s):  
Shenyuan Dai ◽  
Lifang Qiu ◽  
Qichao Chen ◽  
Yanlin Li
Keyword(s):  
Contact Interaction ◽  
Compliant Mechanisms ◽  
Rectangular Cross Section ◽  
Variable Stiffness ◽  
Theoretical Equation ◽  
Flexure Hinge ◽  
Element Analysis ◽  
Equivalent Mechanical Model ◽  
Different Dimensions ◽  
Motion Characteristics

Abstract Flexure hinges are the basis of compliant mechanisms. The stiffness is one of the important indexes to evaluate the performance of a flexure hinge, and the rotation angle when the stiffness changes affects its motion characteristics. Thus, based on the constant rectangular cross-section flexure hinge and contact interaction, this paper proposed a contact-aided variable stiffness flexure hinge (CVSFH). With the deformation under an external load, the contact interaction with different parts of the CVSFH itself can achieve the purpose of variable stiffness. The equivalent mechanical model is built and the theoretical equation of the stiffness is given. CVSFHs with different dimensions are designed, and a finite element analysis (FEA) is done. The FEA results of the design examples are coincide with the theoretical results, which verifies the feasibility of the design and the correctness of the theoretical equation.

Fatigue Study on the Right Circular Flexure Hinges for Designing Compliant Mechanisms

2017 ◽  
Author(s):  
Benliang Zhu ◽  
Yihua Lu ◽  
Min Liu ◽  
Hai Li ◽  
Xianmin Zhang
Keyword(s):  
Maximum Stress ◽  
Compliant Mechanisms ◽  
Fatigue Tests ◽  
Tolerance Limit ◽  
Fatigue Properties ◽  
Flexure Hinge ◽  
Accurate Estimation ◽  
Precision Engineering ◽  
The One ◽  
The Right

Being monolithic with its connected links, the flexure hinge has been widely used for precision engineering where high accuracy is demanded because it has zero friction and backlash. In real application, the flexure hinge is often subjected to periodic loadings, which make it a necessity for its fatigue analysis. In this study, we discussed the fatigue properties of the right circular flexure hinge (RCH). The accurate estimation of the maximum stress in RCH under a certain load is firstly derived. After that, the Stress-Life (S-N) curve was derived from the results of fatigue tests. The design S-N curve (lower-bound S-N curve) was calculated by using the one-sided tolerance limit that derived based on the approximate Owen tolerance limit method. Finally, the effects of the hinge parameters, e.g., the radius r and the thickness t, on the fatigue performance of the RCH were discussed.

Design and analysis of a multi-notched flexure hinge for compliant mechanisms

2017 ◽  
Vol 48 ◽  
pp. 292-304 ◽  
Author(s):  
Min Liu ◽  
Xianmin Zhang ◽  
Sergej Fatikow
Keyword(s):  
Compliant Mechanisms ◽  
Flexure Hinge

A Large-Deflection Annulus-Shape Flexure Hinge Based on Curved Beams

2008 ◽  
Author(s):  
Shanshan Zhao ◽  
Shusheng Bi ◽  
Jingjun Yu ◽  
Minglei Sun ◽  
Guanghua Zhong
Keyword(s):  
Large Deflection ◽  
Compliant Mechanisms ◽  
Accurate Method ◽  
Flexure Hinge ◽  
Curved Beam ◽  
Curved Beams ◽  
Element Analysis ◽  
Rigid Body Model ◽  
Compliant Joint ◽  
Design Tradeoffs

A curved flexure element such as an initially-curved beam can deflect largely and facilely. Using curved flexure elements in compliant mechanisms allows the mechanism to move a longer distance or undergo a larger rotation angle stroke than using conventional notch flexures. This paper presents a novel large-deflection annulus-shaped flexure hinge covering multiple curved-beam flexure elements. It has been shown that geometric symmetry in the constraint arrangement relaxes some of the design tradeoffs, resulting in some improved performances of the flexure hinge. Additional fixed RCM characteristic of isosceles-trapezoidal flexure modules existed in this compliant joint further improve its accuracy. A master-motion pseudo-rigid-body model provides a simple and accurate method to analyze the force-deflection behavior of this new rotary flexure hinge. The accuracy of the model is verified by comparing outcomes to non-linear finite element analysis. The result shows the proposed rotary flexure hinge has a large stroke angle, a low axial and radial stiffness.

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