scholarly journals Analytical Solution of Stiffness for a Corner-Fillet Leaf-Spring Type Flexure Hinge with a Long Fatigue Life

2018 ◽  
Vol 6 (3) ◽  
pp. 64
Author(s):  
Li Rui-qi
Keyword(s):  
Fatigue Life ◽  
Analytical Solution ◽  
Flexure Hinge ◽  
Leaf Spring ◽  
Spring Type

From Shape to Feature - A Novel Structural Design Idea for Dynamic Feature Adjustable Micro Motion Stages Based on Tension Stiffening

2016 ◽  
Vol 679 ◽  
pp. 49-54 ◽  
Author(s):  
Zhi Jun Yang ◽  
Xin Chen ◽  
Su Juan Wang ◽  
Jian Gao ◽  
Xin Du Chen
Keyword(s):  
Structural Design ◽  
Topological Optimization ◽  
Flexure Hinge ◽  
Leaf Spring ◽  
Dynamic Feature ◽  
Tension Stiffening ◽  
Stringed Instruments ◽  
Spring Type ◽  
Micro Motion ◽  
Design Idea

Guidance mechanism such as fast tool servo (FTS) is widely used in precision machining, in the current design method, either the analytic solution or topological optimization, the dynamic feature, namely the stiffness, inertial and frequency, are subjected to the shape and sizing of the designed structure, especially sensitive to the geometric feature of flexure hinge, which caused high machining precision and high cost. In this proceeding, a novel structural design idea for guidance mechanism type micro motion stages based on tension stiffening which allow the dynamic feature adjustable is presented. Firstly, the design of micro motion stages is reviewed on both analytic and topological optimization, and the advantage of the two kinds of commonly used flexure type, the notch type and leaf spring type, are compared, and the latter is chosen as an idea type for guidance mechanism for its uniform deformation and none stress concentration. Secondly, tension stiffening using in the stringed instruments is described, in which the length, tension and linear density is discussed to change the pitch (vibration frequency and amplitude) of the stringed instruments. Finally, a novel structural design idea origin from stringed instruments is discussed, with the assumption that the leaf spring type flexure hinge are symmetrical layout on both sides of the micro motion stage, the stiffness and frequency change rate are also discussed. A numerical method is used to show the efficiency of the presented method.

Optimal Structural Design of Micro-Motion Stage with Stiffness Constraints Using Topology and Sizing Optimization Method

2016 ◽  
Vol 679 ◽  
pp. 55-58
Author(s):  
You Dun Bai ◽  
Zhi Jun Yang ◽  
Xin Chen ◽  
Meng Wang
Keyword(s):  
Compliant Mechanisms ◽  
Optimization Methods ◽  
Flexure Hinge ◽  
Leaf Spring ◽  
Element Analysis ◽  
Sizing Optimization ◽  
Flexure Hinges ◽  
Spring Type ◽  
Micro Motion ◽  
Motion Stage

Flexure hinge is widely used in the compliant mechanisms for precision engineering. Generally, compliant mechanisms with flexure hinges are designed using the analytical stiffness formulas, which increases the design complexity. As the development of finite element analysis (FEA) and optimization methods, it is likely to design the flexure hinges directly using the FEA based numerical optimization methods. This paper developed a leaf spring type flexure hinge based micro-motion stage with specific stiffness constraints. Both topology and sizing optimization methods are used in the design of motion stage. The proposed methods is apply to optimal design formed the leaf spring type flexure hinge for a micro motion stage which serves as a guidance mechanism. Further numerical result shows the good stiffness stability of the refined stage.

scholarly journals Enhanced Axial Tension-tension Fatigue Resistance of a 51CrV4 Spring Steel by Cryogenic Treatment

2020 ◽  
Vol 72 (4) ◽  
pp. 138-151
Author(s):  
Chen Zhi ◽  
Gao Yuan ◽  
Yan Xian-Guo ◽  
Guo Hong ◽  
Huang Yao ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Cryogenic Treatment ◽  
Spring Steel ◽  
Thin Strip ◽  
Leaf Spring ◽  
Axial Tension ◽  
Axial Tensile ◽  
Tensile Fatigue ◽  
Conventional Heat Treatment ◽  
Dump Trucks

51CrV4 spring steel is widely used in heavy duty dump trucks ascribing to its superior mechanical properties. The fatigue life and strength of dump trucks are the main performance indicators that must be considered in the manufacturing process. Cryogenic treatment (CT) can improve the main performance of materials which has been proved by recently research. The effect of cryogenic treatment CT on the axial tensile fatigue strength of 51CrV4 spring steel was studied in this paper. The results showed that the axial tension-tension fatigue life of 51CrV4 spring steel after CT was significantly higher than conventional heat treatment (CHT) samples. The microstructure of 51CrV4 leaf spring material is mainly acicular bainite and thin strip martensite after CT. Compared with CHT, CT makes the microstructure of the material more compact. The introduction of cryogenic treatment (CT) before tempering makes the Ca element in the material aggregate, and the micro amount of Ca has the function of deoxidizing and desulphurizing and improving the morphology of sulfide, thus enhancing the fatigue life of the material.

scholarly journals Fatigue Life Assessment of 65Si7 Leaf Springs: A Comparative Study

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Vinkel Kumar Arora ◽  
Gian Bhushan ◽  
M. L. Aggarwal
Keyword(s):  
Fatigue Life ◽  
Testing Machine ◽  
Life Assessment ◽  
Leaf Spring ◽  
Analytical Technique ◽  
Fatigue Life Assessment ◽  
Leaf Springs ◽  
Light Commercial Vehicle ◽  
Load Rate ◽  
Solid Works

The experimental fatigue life prediction of leaf springs is a time consuming process. The engineers working in the field of leaf springs always face a challenge to formulate alternate methods of fatigue life assessment. The work presented in this paper provides alternate methods for fatigue life assessment of leaf springs. A 65Si7 light commercial vehicle leaf spring is chosen for this study. The experimental fatigue life and load rate are determined on a full scale leaf spring testing machine. Four alternate methods of fatigue life assessment have been depicted. Firstly by SAE spring design manual approach the fatigue test stroke is established and by the intersection of maximum and initial stress the fatigue life is predicted. The second method constitutes a graphical method based on modified Goodman’s criteria. In the third method codes are written in FORTRAN for fatigue life assessment based on analytical technique. The fourth method consists of computer aided engineering tools. The CAD model of the leaf spring has been prepared in solid works and analyzed using ANSYS. Using CAE tools, ideal type of contact and meshing elements have been proposed. The method which provides fatigue life closer to experimental value and consumes less time is suggested.

Fatigue Design Criterion of LCV Leaf Spring Based on Road Load Response Analysis

2005 ◽  
Vol 297-300 ◽  
pp. 322-326
Author(s):  
Il Seon Sohn ◽  
Dong Ho Bae ◽  
Won Seok Jung ◽  
Won Wook Jung
Keyword(s):  
Fatigue Life ◽  
Design Criterion ◽  
Suspension System ◽  
Leaf Spring ◽  
Response Analysis ◽  
Test Mode ◽  
Load Response ◽  
Road Load ◽  
Light Commercial Vehicle ◽  
Driving Condition

Suspension system of light commercial vehicle (LCV) has enough endurance to protect passenger and freight. Leaf spring is major part of LCV suspension system. Thus, fatigue strength evaluation of leaf spring based on road load response was carried out. At first, the strain of leaf spring was measured on the city mode driving condition and proving ground driving condition. And , the damage analysis of road load response was carried out. After that, fatigue test of leaf spring was also carried out. Based on ε-N life relation, fatigue life of leaf spring was evaluated at Belgian mode, city mode and drawing test specification called the 3 steps test mode. Next, it is compared the design life of leaf spring and evaluated fatigue life by the 3steps test mode. From the above, new target of Belgian mode and city mode was proposed to gratify design specification of leaf spring. It is expect that the proposed target can be satisfied leaf spring fatigue endurance at specific road condition.

Comparing Fatigue Life Reliability of a Composite Leaf Spring With a Steel Leaf Spring

Volume 1 ◽  
2004 ◽  
Author(s):  
Nima Shamsaei ◽  
Davood Rezaei
Keyword(s):  
Fatigue Life ◽  
Fatigue Behavior ◽  
Minimum Weight ◽  
Time Spectrum ◽  
Leaf Spring ◽  
Critical Element ◽  
Steel Spring ◽  
Leaf Springs ◽  
Long Time ◽  
External Forces

In the present study, the fatigue behavior of an optimized composite leaf spring and a four leaf steel spring have been analyzed and compared. In a paper, issued by co-author, a four leaf steel spring was replaced by a composite leaf spring. The geometry of composite spring has been optimized to obtain the minimum weight under stress and displacement constraints due to the given static external forces. In this study, both above-mentioned leaf springs have been fatigue analyzed. The vehicle movement has been simulated on four different standard roads in ADAMS software and the spring supports reactions have been derived. Stress time spectrum micro-blocks in critical element of leaf springs have been obtained using ANSYS software and considering ADAMS results as loading. The stress time spectrum macro-blocks for long time from the stress time spectrum in micro-blocks have been created according to statistical and random vibration principles. After finding stress probability density functions for composite leaf spring and equivalent steel leaf spring, fatigue reliabilities have been extracted for both of them. Results showed that the fatigue life reliability in composite leaf spring is much better than steel spring.

scholarly journals Static Analysis and Fatigue Life Prediction of Composite Leaf Springs of Automotive Suspension System

2019 ◽  
Vol 8 (4) ◽  
pp. 5147-5150
Keyword(s):  
Fatigue Life ◽  
Fuel Efficiency ◽  
Life Cycles ◽  
Life Assessment ◽  
Leaf Spring ◽  
Commercial Vehicles ◽  
Safety Standards ◽  
The Road ◽  
Leaf Springs ◽  
Automotive Suspension

Development of vehicles with the highest safety standards and lowest carbon emissions has been one of the primary goals of the automobile manufacturers. One of the methods of achieving higher fuel efficiency is by reducing vehicle weight by minimizing the unsprung weight without compromising strength and driver comfort. The study presents the behavior of the double-bolted-end joint semi-elliptical leaf spring that is generally used in the rear suspension of lightweight cars and commercial vehicles. 65si7 grade steel is conventionally used in the above leaf springs. The study evaluates the stress distribution, deflection and fatigue life assessment of leaf springs made up of glass epoxy (62% glass fiber), carbon epoxy (40% carbon fiber), and aluminum graphite (5% graphite). The results are compared with 65si7 steel leaf spring and analysed. The analysis performed showed a weight reduction of 76.4 %, 81.1%, 65.8% respectively. The first natural frequency was approximately 1.2 times greater than the road frequency. The simulated results for fatigue life cycles of leaf spring (10e5 cycles) was observed, whereas, for the conventional steel leaf spring (2e5 cycles) was observed. The results suggest the material aluminum graphite (5% graphite) will be the best replacement, considering the overall weight to strength ratio and cost

scholarly journals A Simplified Flexible Multibody Dynamics for a Main Landing Gear with Flexible Leaf Spring

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Zhi-Peng Xue ◽  
Ming Li ◽  
Yan-Hui Li ◽  
Hong-Guang Jia
Keyword(s):  
Linear Theory ◽  
Mass Matrix ◽  
Flexible Multibody Dynamics ◽  
Landing Gear ◽  
Leaf Spring ◽  
Dynamics Of Multibody Systems ◽  
Small Uav ◽  
Flexible Multibody ◽  
Flexible Part ◽  
Spring Type

The dynamics of multibody systems with deformable components has been a subject of interest in many different fields such as machine design and aerospace. Traditional rigid-flexible systems often take a lot of computer resources to get accurate results. Accuracy and efficiency of computation have been the focus of this research in satisfying the coupling of rigid body and flex body. The method is based on modal analysis and linear theory of elastodynamics: reduced modal datum was used to describe the elastic deformation which was a linear approximate of the flexible part. Then rigid-flexible multibody system was built and the highly nonlinearity of the mass matrix caused by the limited rotation of the deformation part was approximated using the linear theory of elastodynamics. The above methods were used to establish the drop system of the leaf spring type landing gear of a small UAV. Comparisons of the drop test and simulation were applied. Results show that the errors caused by the linear approximation are acceptable, and the simulation process is fast and stable.

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