scholarly journals Flexibility Calculation of Like-U Type Flexure Hinge

2015 ◽  
Vol 9 (1) ◽  
pp. 532-539
Author(s):  
Ling Jingjing ◽  
Li Ruiqin ◽  
Zhang Qisheng
Keyword(s):  
Flexure Hinge ◽  
Structural Parameter ◽  
Computational Formula ◽  
Theoretical Base ◽  
Technical Application ◽  
Flexure Hinges ◽  
Accurate Design ◽  
Computation Formula ◽  
Analytic Computation ◽  
Good Agreement

A new like-U type flexure hinge structure is proposed, based on Castigliano’s second theorem and calculus theory. Taking the centrifugal angle parameters as the integration variable, and defining the intermediate parameters, it deduces the analytic computational formula for the like-U type flexure hinge flexibility. By changing the structural parameter of the flexure hinge, it is able to transform four different structure flexure hinges, and the deduced analytic computation formula can be applied to all of these four structures flexure hinges. After the twelve flexure hinges of different structures have been analyzed by applying finite-element method, it is found that the results are in good agreement with the results of analytic computation formula. Thus, the validity of the analytic computation formula is verified, realize accurate design and computation for such flexure hinges is realized, and the theoretical base for technical application of like-U type flexure hinge is provided.

scholarly journals Large Stroke Performance Optimization of Spatial Flexure Hinges

2012 ◽  
Author(s):  
D. H. Wiersma ◽  
S. E. Boer ◽  
R. G. K. M. Aarts ◽  
D. M. Brouwer
Keyword(s):  
Performance Optimization ◽  
Geometric Model ◽  
Optimal Solution ◽  
Element Model ◽  
Flexure Hinge ◽  
Multibody Modeling ◽  
Optimization Constraints ◽  
Flexure Hinges ◽  
Measure Of Performance ◽  
Good Agreement

Flexure hinges inherently lose stiffness in supporting directions when deflected. In this paper a method is presented for optimizing the geometry of flexure hinges, while supporting stiffnesses are retained. These hinges are subjected to a load and deflected an angle of up to ±20°. The measure of performance is defined by the first unwanted eigenfrequency, which is closely related to the supporting stiffnesses. During the optimization, constraints are applied to the actuation moment and the maximum occurring stress. Evaluations of three cross flexure hinge types and a butterfly flexure hinge are presented. A flexible multibody modeling approach is used for efficient modeling. Each of these hinge types is described by a parameterized geometric model. The obtained optimal hinge designs are validated with a finite element model and show good agreement. The optimal solution of the butterfly flexure hinge shows the least decrease in the supporting stiffnesses of the evaluated hinges.

The Light Field And The Scope Of Light Science

2021 ◽  
pp. 4-10
Author(s):  
Vladimir P. Budak ◽  
Julian B. Aizenberg
Keyword(s):  
Remote Sensing ◽  
Plant Growth ◽  
Electricity Generation ◽  
Light Field ◽  
Theoretical Foundation ◽  
Theoretical Base ◽  
Technical Application ◽  
Single Section ◽  
Lighting Systems ◽  
Effective Development

For centuries, light has been produced to enable the human visual system to operate but, today, light is being used for an increasing number of non-visual, technical purposes. Examples include plant growth, remote sensing, electricity generation, and communication. This paper discusses the theoretical foundation of such technical applications of light and shows that it is completely identical to the fundamentals of lighting. The foundation is the theory of the light field, which is generated by the interaction of the radiation field with a quadratic (energy) receiver. Within its range of applicability, the theory of the light field is complete and closed. As a result, the light field provides a unified theoretical base for lighting systems and the technical application of light. This creates the basis for combining them into a single section of science and technology, which will ensure their effective development and application.

scholarly journals Accurate Design of Solar Selective Absorber Based on Measured Optical Constants of Nano-thin Cr Film

Coatings ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 938
Author(s):  
Zheng-Yong Wang ◽  
Er-Tao Hu ◽  
Qing-Yuan Cai ◽  
Jing Wang ◽  
Hua-Tian Tu ◽  
...  
Keyword(s):  
Optical Constants ◽  
Optimization Method ◽  
Global Optimization Method ◽  
Photothermal Conversion ◽  
Working Temperature ◽  
Absorption Layer ◽  
Accurate Design ◽  
Metal Absorption ◽  
Cr Film ◽  
Good Agreement

Solar selective absorbers have significant applications in various photothermal conversion systems. In this work, a global optimization method based on genetic algorithm was developed by directly optimizing the solar photothermal conversion efficiency of a nano-chromium (Cr) film-based solar selective absorber aiming to work at the specified working temperature and solar concentration. In consideration of the semi-transparent metal absorption layer employed in multilayered solar selective absorbers, the optical constants of ultrathin Cr film were measured by spectroscopic ellipsometer and introduced into the optimization process. The ultrathin Cr film-based solar selective absorber was successfully designed and fabricated by the magnetron sputtering method for the working temperature at 600 K and a solar concentration of 1 Sun. The measured reflectance spectra of the sample show a good agreement with the numerical simulations based on measured optical constants of ultrathin Cr film. In comparison, the simulated results by using the optical constants of bulk Cr film or literature data exhibit a large discrepancy with the experimental results. It demonstrates the significance of considering the actual optical constants for the semi-transparent metal absorption layer in the design of nano-metal film-based solar selective absorber.

An Empirically Determined Design Guideline for Rectangular Cross Section Nitinol Flexure Hinges With the Focus on Flexibility-Strength Trade-Off

2018 ◽  
Author(s):  
S. Coemert ◽  
M. Olmeda ◽  
J. Fuckner ◽  
C. Rehekampff ◽  
S. V. Brecht ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Cross Section ◽  
Electrical Discharge Machining ◽  
Rectangular Cross Section ◽  
Flexure Hinge ◽  
Element Analysis ◽  
Design Guideline ◽  
Trade Off ◽  
Flexure Hinges ◽  
Compliance Modeling

In our group, we are developing flexure hinge based manipulators made of nitinol for minimally invasive surgery. On the one hand, sufficient flexibility is required from flexure hinges to be able to cover the surgical workspace. On the other hand, the bending amount of the flexure hinges has to be limited below the yielding point to ensure a safe operation. As a result of these considerations, it has to be questioned how much bending angle a nitinol flexure hinge with given geometric dimensions can provide without being subject to plastic deformation. Due to the nonlinearities resulting from large deflections and the material itself, the applicability of the suggested approaches in the literature regarding compliance modeling of flexure hinges is doubtful. Therefore, a series of experiments was conducted in order to characterize the rectangular cross section nitinol flexure hinges regarding the flexibility-strength trade-off. The nitinol flexure hinge samples were fabricated by wire electrical discharge machining in varying thicknesses while keeping the length constant and in varying lengths while keeping the thickness constant. The samples were loaded and unloaded incrementally until deflections beyond visible plastic deformation occured. Each pose in loaded and unloaded states was recorded by means of a digital microscope. The deflection angles yielding to permanent set values corresponding to 0.1% strain were measured and considered as elastic limit. A quasilinear correlation between maximum elastic deflection angle and length-to-thickness ratio was identified. Based on this correlation, a minimal model was determined to be a limit for a secure design. The proposed guideline was verified by additional measurements with additional samples of random dimensions and finite element analysis.

Design optimization of high-precision aerostatic equipment based on orifice restriction

2019 ◽  
Vol 233 (10) ◽  
pp. 3459-3474
Author(s):  
Tao Lai ◽  
Xiaoqiang Peng ◽  
Junfeng Liu ◽  
Chaoliang Guan ◽  
Xiaogang Chen ◽  
...  
Keyword(s):  
Finite Difference Method ◽  
High Precision ◽  
Structural Parameter ◽  
Error Feedback ◽  
Aerostatic Bearing ◽  
Proposed Model ◽  
Gas Gap ◽  
Processing Difficulty ◽  
Optimum Working ◽  
Good Agreement

The aerostatic lubrication model with orifice restriction is built based on finite difference method. The model is solved by combination of flux-error feedback and optimization of grids parameter. The stiffness of aerostatic bearing can be improved by reducing the diameter of the orifice, but the optimum working gas gap is reduced and the processing difficulty of surface throttle is improved. The experiments of load and stiffness are carried out on the slider (50 × 50 mm) with the diameter of orifice at 50 µm. The experimental results and theoretical calculation are in good agreement; thus, the model is verified. The structural parameter of two, three, and four orifice gas-bearings is optimized, respectively, based on the proposed model, and the optimum positions of the orifices are obtained. According to the results, the aerostatic bearing guideways, made up of optical material (K9), are manufactured by some optical ways, and the lubrication of the small gas gap is guaranteed; meanwhile, the straightness accuracy of the aerostatic bearing guideways is 0.1 µm/200 mm. The analysis result verifies that the calculation method and the aerostatic lubrication model are significant to the design of high-precision aerostatic equipment.

ROUGHENING TRANSITION IN BRANCHING POLYMERS

Fractals ◽  
2003 ◽  
Vol 11 (supp01) ◽  
pp. 29-36 ◽  
Author(s):  
LIACIR S. LUCENA ◽  
LUCIANO R. DA SILVA ◽  
STÉPHANE ROUX
Keyword(s):  
Phase Diagram ◽  
Phase Boundary ◽  
Branching Ratio ◽  
Direct Numerical Simulations ◽  
Branched Polymers ◽  
Heterogeneous Environment ◽  
Original Algorithm ◽  
Roughening Transition ◽  
Analytic Computation ◽  
Good Agreement

A growth model, introduced to model the development of branched polymers in an heterogeneous environment, gives rise to clusters whose boundary is either faceted or rough. We study the transition between these two morphologies as a function of the parameters of the model, impurity concentration and branching ratio. The phase diagram is first obtained by direct numerical simulations, using an original algorithm, based on a self-regulated search of a critical point. Then an analytic computation of the phase boundary is proposed based on a simple approximation. The obtained phase boundary is in good agreement with the numerical results. The nature of the transition is discussed.

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.

Corner-Filleted Flexure Hinges

2000 ◽  
Vol 123 (3) ◽  
pp. 346-352 ◽  
Author(s):  
Nicolae Lobontiu ◽  
Jeffrey S. N. Paine ◽  
Ephrahim Garcia ◽  
Michael Goldfarb
Keyword(s):  
Finite Element ◽  
Closed Form ◽  
Finite Element Simulation ◽  
Analytical Approach ◽  
Flexure Hinge ◽  
Closed Form Solutions ◽  
Flexure Hinges ◽  
Element Simulation ◽  
Model Predictions ◽  
The Right

The paper presents an analytical approach to corner-filleted flexure hinges. Closed- form solutions are derived for the in-plane compliance factors. It is demonstrated that the corner-filleted flexure hinge spans a domain delimited by the simple beam and the right circular flexure hinge. A comparison that is made with the right circular flexure hinges indicates that the corner-filleted flexures are more bending-compliant and induce lower stresses but are less precise in rotation. The finite element simulation and experimental results confirmed the model predictions.

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.

Performance Optimization of Flexure Hinges Using Genetic Algorithm

2011 ◽  
Vol 121-126 ◽  
pp. 4542-4546
Author(s):  
Bing Li ◽  
Jin Gou
Keyword(s):  
Genetic Algorithm ◽  
Objective Function ◽  
Performance Optimization ◽  
Flexure Hinge ◽  
Flexure Hinges ◽  
Maximum Value

The flexure hinge is an important part of micro-displacement table in the precision instruments. To improve the performance of micro-displacement table, the key parameters of its flexure hinges: radius and thickness of hinge and length of connecting rods etc. are studied. Aiming at a commonly used parallel four-bar flexure hinges structure, the parameters of flexure hinge are optimized by using the genetic algorithm under the condition that the frequency of objective function approaches a maximum value.

Sign in / Sign up

Export Citation Format

Share Document