Using the Parts Used to Be Removed to Improve Compliant Joint’s Performance

2018 ◽  
Author(s):  
Zhongtian Xie ◽  
Lifang Qiu ◽  
Debin Yang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Compliant Mechanisms ◽  
Great Influence ◽  
3D Models ◽  
Element Analysis ◽  
Design Concepts ◽  
Compliant Joints ◽  
Tension And Compression ◽  
Design And Manufacture

Compliant mechanisms gain their mobility from the deflection of flexible members. Compliant joints are the basis of compliant mechanisms, their performance has great influence on compliant mechanisms’ characteristics. This paper presents the concept that the parts used to be removed during design and manufacture processes can be retained and redesigned to improve compliant joints’ performance. They are designed specially to help to improve the joints’ ability to resist tension and compression. Some examples are proposed and discussed. 3D models are created and analyzed using finite element analysis (FEA) to verify the design concepts. A benchmark Lamina Emergent Torsional (LET) joint is also analyzed through FEA. The results obtained from FEA confirm the design concepts presented in this paper very well. Some other applications are also proposed and discussed.

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.

Research on the Structural Performance of Large-Tonnage Gantry Crane

2013 ◽  
Vol 823 ◽  
pp. 247-250
Author(s):  
Jie Dong ◽  
Wen Ming Cheng ◽  
Yang Zhi Ren ◽  
Yu Pu Wang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Theoretical Calculations ◽  
Complex Structure ◽  
Early Period ◽  
Operating Conditions ◽  
Structural Performance ◽  
Gantry Crane ◽  
Element Analysis ◽  
Design And Manufacture

Because of the huge lifting weight and complex structure of large-tonnage gantry crane and in order to effectively design and review it, this paper aims to carry out a research on its structural performance based on the method of theoretical calculation and finite element analysis. During the early period of design, the method of theoretical calculations is adopted, and after specific design it comes the finite element analysis, so as to get the results of analysis under a variety of operating conditions, which illustrates that the structural design and review of large-tonnage gantry crane based on theoretical calculations and finite element are feasible, and also verifies that the method of finite element is an effective way to find a real dangerous cross-section, thus providing the basis for the design and manufacture of the crane structure.

Design, analysis and test of a novel cylinder-driven mode applied to microgripper

2021 ◽  
pp. 1-14
Author(s):  
Xiaodong Chen ◽  
ZM Xie ◽  
Huifeng Tan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Compliant Mechanisms ◽  
Research Field ◽  
Driving Pressure ◽  
Maximum Output ◽  
Element Analysis ◽  
Output Displacement ◽  
Micro Parts ◽  
The Relationship

Abstract How to enlarge the output displacement is a key issue in the research field of microgrippers. It is difficult to further enlarge the output displacement for the traditional displacement transmission mechanism (DTM). In this research, a two-stage amplification cylinder-driven DTM based on the compliant mechanisms is designed to realize the displacement output expansion. The opening and closing of the clamping jaws is driven by the air cylinder to enlarge the output displacement of the microgripper. According to the analysis of statics model of the mechanism, the relationship between the output displacement of the microgripper and the driving pressure of the cylinder is established. The magnification of the microgripper is obtained using a dynamic model. Moreover, based on the finite element analysis, the mechanical structure parameters are optimized. The microgripper was fabricated by utilizing wire electro discharge machining (WEDM) technique, and then a series of experiments were carried out to obtain the relationship between the displacement and the driving pressure. It is found that the maximum output displacement measured is 1190.4μm under the pressure of 0-0.6 Mpa, corresponding to the magnification of 47.63. Compared with the results of finite element analysis and theoretical calculation, the test results have a discrepancy of 2.39% and 6.62%, respectively. The microgripper has successfully grasped a variety of micro-parts with irregular shapes, and parallel grasping can be achieved, demonstrating the potential application of this design in the field of micromanipulation.

An Improved Method for Designing Flexure-Based Nonlinear Springs

2012 ◽  
Author(s):  
Qiaoling Meng ◽  
Giovanni Berselli ◽  
Rocco Vertechy ◽  
Vincenzo Parenti Castelli
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Compliant Mechanisms ◽  
Empirical Equations ◽  
Element Analysis ◽  
Closed Form Solutions ◽  
Nonlinear Springs ◽  
Aspect Ratios ◽  
Analytical Relations ◽  
Flexural Hinges

Monolithic Flexure-based Compliant Mechanisms (MFCM) can functionally act as nonlinear springs by providing a desired load-displacement profile at one point on their structure. Once the MFCM topology is chosen, these particular springs can be conveniently synthesized by resorting to the well-known Pseudo-Rigid-Body approximation, whose accuracy strongly depends on the modeling precision of the flexures’ principal compliance. For various types of flexures, closed-form solutions have been proposed which express the compliance factors as functions of the flexure dimensions. Nonetheless, the reliability of these analytical relations is limited to slender, beam-like, hinges undergoing small deflections. In order to overcome such limitations, this paper provides empirical equations, derived from finite element analysis, that can be used for the optimal design of circular, elliptical, and corner-filleted flexural hinges with general aspect ratios on the basis of both principal compliance and maximum bearable stress. As a case study, a nonlinear spring conceived as a four-bar linkage MFCM is synthesized and simulated by means of finite element analysis. Numerical results confirm that the aforementioned empirical equations outperform their analytical counterparts when modeling thick cross-section hinges undergoing large deflections.

Mechanical Behaviour of Auxetic Microstructures Using Contact Mechanics and Elastoplasticity

2016 ◽  
Vol 681 ◽  
pp. 100-116
Author(s):  
Georgios A. Drosopoulos ◽  
Nikolaos Kaminakis ◽  
Nikoletta Papadogianni ◽  
Georgios E. Stavroulakis
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Topology Optimization ◽  
Contact Mechanics ◽  
Compliant Mechanisms ◽  
Nonlinear Finite Element Analysis ◽  
Nonlinear Finite Element ◽  
Numerical Homogenization ◽  
Element Analysis ◽  
Optimization Formulation

The design of novel mechanical microstructures having auxetic behaviour is proposed in this paper using techniques of topology optimization for compliant mechanisms. The resulting microstructure can be modified in order to cover additional needs, not included in the topology optimization formulation. Classical structural optimization, contact mechanics, homogenization and nonlinear finite element analysis are used for this step. Thus, the modified microstructure or composite is studied with numerical homogenization in order to verify that it still has the wished auxetic behaviour. Finally, nonlinear finite element analysis shows how the auxetic behaviour is influenced by unilateral contact between the constituent materials, large displacements and elastoplasticity.

Finite Element Analysis of the Evolution of Damage during Equal Channel Angular Pressing of a Mg–3Al–1Zn Alloy

2012 ◽  
Vol 482-484 ◽  
pp. 2418-2423
Author(s):  
Feng Kang ◽  
Jing Tao Wang ◽  
Ping Cheng ◽  
Hai Ying Wu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Equal Channel Angular Pressing ◽  
Initial Crack ◽  
Flow Localization ◽  
Element Analysis ◽  
Fracture Characteristics ◽  
Angular Pressing ◽  
Tension And Compression ◽  
Simulation Results

Finite element analysis was used to simulate the evolution of damage in a Mg–3Al–1Zn alloy processed by equal channel angular pressing (ECAP). Oyane criterion for damage was selected to evaluate the fracture characteristics. Finite element modeling was used with experimental data obtained from tension and compression testing. The results show that initial crack may form in severe flow localization (i.e. in the inner corner) and these cracks may propagate, leading to billet segmentation. The flow grid in the simulation results is similar to that in the previous experimental results.

scholarly journals Evaluation of U10Mo Fuel Plate Irradiation Behavior via Numerical and Experimental Benchmarking

2012 ◽  
Author(s):  
Samuel J. Miller ◽  
Hakan Ozaltun
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
3D Models ◽  
Creep Model ◽  
Element Analysis ◽  
Dimensional Changes ◽  
3 Dimensional ◽  
Out Of Plane ◽  
2D And 3D ◽  
Irradiation Behavior

This article analyzes dimensional changes due to irradiation of monolithic plate-type nuclear fuel and compares results with finite element analysis of the plates during fabrication and irradiation. Monolithic fuel plates tested in the Advanced Test Reactor (ATR) at Idaho National Lab (INL) are being used to benchmark the performance of proposed fuel for several high power research reactors. Post-irradiation metallographic images of plates sectioned at the mid-plane were analyzed to determine dimensional changes of the fuel and the cladding response. A constitutive model of the fabrication process and irradiation behavior of the tested plates was developed using the general purpose commercial finite element analysis package, ABAQUS. Using calculated burn-up profiles of irradiated plates to model the power distribution and including irradiation behaviors such as swelling and irradiation enhanced creep, model simulations allow analysis of plate parameters that are either impossible or infeasible in an experimental setting. The development and progression of fabrication induced stress concentrations at the plate edges was of primary interest, as these locations have a unique stress profile during irradiation. Additionally, comparison between 2D and 3D models was performed to optimize analysis methodology. In particular, the ability of 2D and 3D models to account for out of plane stresses which result in 3-dimensional creep behavior that is a product of these components. Results show that assumptions made in 2D models for the out-of-plane stresses and strains cannot capture the 3-dimensional physics accurately and thus 2D approximations are not representative. Stress-strain fields are dependent on plate geometry and irradiation conditions, thus, if stress based criteria is used to predict plate behavior (as opposed to material impurities, fine micro-structural defects, or sharp power gradients), unique 3D finite element formulation for each plate is required.

Finite Element Analysis of Ship Lock Chamber Structure

2014 ◽  
Vol 1065-1069 ◽  
pp. 597-600
Author(s):  
Chao Sun ◽  
Zi Chang Shang Guan ◽  
Xiao Xuan Wang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Element Modeling ◽  
Base Plate ◽  
3D Models ◽  
Element Analysis ◽  
Calculation Process ◽  
Lock Chamber ◽  
Set Up ◽  
Ship Lock

While considering various structural and material requirements, 3D models of ship chambers in the ship lock structure using finite element modeling (FEM) software ANSYS. By using FEM software to set up the contacting sections between the base plate, refilled soils and foundation, analyses were done to caluculate the forces exerted on the structure of the ship chamber. After checking the reasonability of the calculated results, discussions were made on the calculation process to allow for future empirical calculations.

scholarly journals Finite Element Analysis and Full-Scale Testing of Locomotive Crashworthy Components

2013 ◽  
Author(s):  
Patricia Llana ◽  
Richard Stringfellow ◽  
Ronald Mayville
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
New Technologies ◽  
Element Model ◽  
Full Scale ◽  
Element Analysis ◽  
Design Concepts ◽  
Dynamic Finite Element Analysis ◽  
Full Scale Tests ◽  
Force Displacement

The Office of Research and Development of the Federal Railroad Administration (FRA) and the Volpe Center are continuing to evaluate new technologies for increasing the safety of passengers and operators in rail equipment. In recognition of the importance of override prevention in train-to-train collisions in which one of the vehicles is a locomotive, and in light of the success of crash energy management technologies in cab car-led passenger trains, the Volpe Center seeks to evaluate the effectiveness of components that could be integrated into the end structure of a locomotive that are specifically designed to mitigate the effects of a collision and, in particular, to prevent override of one of the lead vehicles onto the other. A research program has been conducted to develop, fabricate and test two crashworthy components for the forward end of a locomotive: (1) a deformable anti-climber, and (2) a push-back coupler. Detailed designs for these components were developed, and the performance of each design was evaluated through large deformation dynamic finite element analysis (FEA). Designs for two test articles that could be used to verify the performance of the component designs in full-scale tests were also developed. The two test articles were fabricated and dynamically tested by means of rail car impact in order to verify certain performance characteristics of the two components relative to specific requirements. The tests were successful in demonstrating the effectiveness of the two design concepts. Test results were consistent with finite element model predictions in terms of energy absorption capability, force-displacement behavior and modes of deformation.

scholarly journals Sealing Mechanics Study of Laryngeal Mask Airways via 3D Modeling and Finite Element Analysis

2021 ◽  
Author(s):  
Hongxia Liao ◽  
Liqiang Chen ◽  
Junfeng Chen
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cuff Pressure ◽  
3D Models ◽  
Laryngeal Mask ◽  
Comprehensive Understanding ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Sealing Mechanism ◽  
Mucosal Pressure

Abstract Background: Proper sealing of laryngeal mask airways (LMAs) is critical for airway management in clinical use. A good understanding of the LMA sealing mechanism provides a scientific foundation to improve the sealing of LMAs to reduce the incidence of adverse events. However, no existing methods provide a systematic study on the LMA sealing mechanics. Methods: Computer-aided 3D models are established to visualize LMA – pharynx interactions directly. The finite element analysis (FEA) is adopted to study the LMA sealing mechanics. Results: Two case studies are provided in the paper. The LMA is loaded with a low cuff pressure (CP) (9 mmHg) to investigate the cause of leaking in Case I, and with a high CP (45 mmHg) to detect the critical points of high mucosal pressure in Case II. The established 3D models provide initiative visualization of the sealing situations. The visualization results are verified by pressure distribution along the contacting surface generated from FEA as the quantitative study. Conclusions: Compared with the existing methods, the proposed method does not introduce additional cost, and can provide globe monitoring on the LMA and a comprehensive understanding of sealing mechanics in all areas. The findings on the sealing mechanism and corresponding suggestions for clinic use of LMAs and LMA design have also been presented in the paper.

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