scholarly journals The Effect of Displacement Constraints on the Failure of MEMS Tuning Fork Gyroscopes under Shock Impact

Micromachines ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 343 ◽  
Author(s):  
Jiangkai Lian ◽  
Jianhua Li ◽  
Lixin Xu
Keyword(s):  
Tuning Fork ◽  
Element Analysis ◽  
Practical Applications ◽  
Displacement Constraint ◽  
Shock Impact ◽  
Cause Of Failure ◽  
Multiple Collisions ◽  
Shock Resistance ◽  
Displacement Constraints ◽  
Two Degree Of Freedom

Displacement constraints such as stops are widely used in engineering to improve the shock resistance of microelectromechanical system (MEMS) tuning fork gyroscopes. However, in practical applications, it has been found that unexpected breakage can occur on MEMS tuning fork gyroscopes with stops. In this paper, the effects of two displacement constraints on the failure mode of MEMS tuning fork gyroscopes are studied. The MEMS tuning fork gyroscope is simplified to a two-degree-of-freedom (2DOF) model, then finite element analysis (FEA) is used to study the effects of displacement constraint on the gyroscope. The analysis proves that even if the displacement constraint of direct contact with the weak connecting beam is not established, the equivalent stiffness of the gyroscope can be enhanced by limiting the displacement of the movable mass, thereby improving the shock resistance of the gyroscope. However, under the shock of high-g level, displacement constraint with insufficient spacing will cause multiple collisions of the small-stiffness oscillating frame and lead to an increase in stress. The cause of failure and shock resistance of a MEMS tuning fork gyroscope are verified by the shock test. By comparing the results, we can get a conclusion that is consistent with the theoretical analysis.

Finite Element Analysis for Shock Resistance Evaluation of Cushion-Packaged Multifunction Printer Considering Internal Modules

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Se-Chang Kim ◽  
Dae-Geun Cho ◽  
Tae-Gyu Kim ◽  
Se-Hun Jung ◽  
Ja-Choon Koo ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Shock Acceleration ◽  
External Shocks ◽  
Compression Tests ◽  
Element Analysis ◽  
Dynamic Behaviors ◽  
Shock Resistance ◽  
The Impact ◽  
Multifunction Printer

Failures in IT electronics are often caused by falling or external shocks during transportation. These failures cause customers to mistrust the reliability of the products. Many manufacturers of IT electronics have not only used cushioning materials but also increased the shock resistance of their products for failure prevention. Especially in case of printer products, the design of the packaging and the product robustness are extremely important because of their substantial weight and the fragility of the internal modules. For product design, it is essential to understand the impact failure mechanism of the products. In this study, a compression test, a drop impact test, and a finite element analysis (FEA) were performed to analyze the dynamic behaviors of a packaged multifunction printer (MFP). The mechanical properties of a cushioning material were measured by compression tests. The FE models of the cushion packaging and the MFP included the physical characteristics of the internal modules, and their dynamic behaviors were obtained using the commercial software ls-dyna3d. Simulation results were also compared with drop test results to verify the proposed FE models. The shock resistance of the MFP was assessed by stress analysis and strength evaluation. We also expect our FE models will be useful for evaluating the fragility of the internal modules because the models can numerically estimate the shock acceleration profiles of the internal modules, which are difficult to measure experimentally.

Design and testing of a novel multipath-actuation compliant manipulator

2021 ◽  
Vol 32 (2) ◽  
pp. 025004
Author(s):  
Xu Yang ◽  
Lichao Ji ◽  
Wule Zhu ◽  
Ying Shang ◽  
Shizhen Li
Keyword(s):  
Dynamic Performance ◽  
Large Displacement ◽  
Element Analysis ◽  
Static And Dynamic Characteristics ◽  
Amplification Ratio ◽  
Practical Applications ◽  
Directional Motion ◽  
Branched Chains ◽  
Design And Testing ◽  
The Ideal

Abstract In this paper, a novel multipath-actuation compliant manipulator (MCM) driven by piezoelectric actuators is proposed. Specifically, the monolithic MCM employs two vertically arranged compliant limbs with multipath motion transmission to actuate a symmetrically constrained planar mechanism, realizing x- and y-directional motion. For each limb, the multiple branched chains are configured in different paths but all contribute to the output motion, which results in a large displacement amplification ratio as well as a high working bandwidth. The ideal motion transmission of the proposed MCM is revealed by a specially established rigid-body kinematics model. Finite element analysis is carried out to predict the realistic static and dynamic performance of designed MCM. Moreover, a monolithic MCM prototype is fabricated, which is demonstrated to have a large displacement amplification ratio of 11.05, a high resonance frequency of 969 Hz, and a fine motion resolution of 25.48 nm. With promising static and dynamic characteristics, the proposed MCM can be widely used in practical applications.

scholarly journals Response of a Two-Degree-of-Freedom Vibration System with Rough Contact Interfaces

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Zhiqiang Huang ◽  
Xun Peng ◽  
Gang Li ◽  
Lei Hao
Keyword(s):  
Natural Frequency ◽  
Degree Of Freedom ◽  
Element Analysis ◽  
Chaotic Motions ◽  
First Order ◽  
Vibration Properties ◽  
Ground System ◽  
Jump Frequencies ◽  
Two Degree Of Freedom ◽  
Seismic Vibrator

This paper is focused on the influence of the rough contact interfaces on the dynamics of a coupled mechanical system. For this purpose, a two-degree-of-freedom model of a coupled seismic-vibrator-rough-ground system is proposed with which the nonlinear vibration properties are analyzed. In this model, the force-deflection characteristic of the contact interfaces is determined by finite element analysis. By analyzing the undamped free vibration, it was found that the variation of the second-order natural frequency with amplitude increases with rougher contact interfaces; however, the amplitude has little influence on the first-order natural frequency of the system. For the harmonic excited analysis, the jump frequencies and hysteretic region both decrease with rougher contact interfaces. Moreover, it is inferred from the bifurcation diagrams that, increasing the excitation force, the system can bring about chaotic motions on rough contact interfaces.

Study on the transmission characteristics of magnetic resonance wireless power transfer system

2017 ◽  
Vol 9 (9) ◽  
pp. 1799-1807
Author(s):  
Xiufang Wang ◽  
Yu Wang ◽  
Yilang Liang ◽  
Guangcheng Fan ◽  
Xinyi Nie ◽  
...  
Keyword(s):  
High Efficiency ◽  
Magnetic Coupling ◽  
Wireless Power Transfer ◽  
Parameter Extraction ◽  
Magnetic Flux Density ◽  
Power Transfer ◽  
Wireless Power ◽  
Element Analysis ◽  
Practical Applications ◽  
Power Transfer Efficiency

Magnetic coupling resonance wireless power transfer technology has attracted worldwide attention in recent years due to its mid-range, non-radiative, and high-efficiency power transfer. However, in regard to its practical applications, there are still some issues that need to be considered and studied with respect to coil design, such as coil structure, and parasitic parameter extraction. This paper investigated the characteristics of magnetic coupling resonance wireless power transfer systems with different coil structures, including circular coils and rectangular coils arranged in parallel. We calculated the magnetic field distributions and mutual inductances by subdividing the receiving coils and computing the magnetic flux density of each subdivision. The proposed analysis was validated by means of the finite element analysis and the experimental results. We investigated the effects of the coil's structure, and topological structures, on the power transfer efficiency. The results demonstrate that using circular coils in parallel is more advantageous than using rectangular coils.

Effect of Bolt Strength and Loading Conditions on a 7/8” Bolt Within an End-of-Car Arrangement

2008 ◽  
Author(s):  
Andrew D. Smyth
Keyword(s):  
Finite Element Analysis ◽  
Material Properties ◽  
External Loading ◽  
Loading Conditions ◽  
Element Analysis ◽  
Bolt Preload ◽  
Cause Of Failure ◽  
Bolt Failure ◽  
Inherent Strength ◽  
Type Of Failure

A cause of failure within end-of-car (EOC) arrangements for cushioned cars with F-shank couplers is that of the yoke bolt failing in shear. This mode of EOC failure is of particular concern due to the concealed nature of the bolt not easily allowing for early detection of the onset of failure. To this end, a finite element analysis (FEA) was performed on a 7/8” bolt and F-bracket assembly to determine the stress state developed within the bolt in an effort to understand the potential cause or causes for the bolt failure. Several parameters, including bolt strength, bolt preload (initial torque), and external loading were varied to determine their effects on bolt performance. The subsequent results indicate that both inherent strength and initial preload have a significant effect on whether a bolt can effectively withstand the various external loading conditions encountered in the field. In addition, it is also apparent that some of the simulation loading scenarios analyzed contain the potential to initiate bolt shearing during operation. From these results, some failure mechanism theories are proposed to describe the type of failure encountered by each bolt grade, either ductile or brittle depending on the inherent material properties.

A Two Degree of Freedom Nanopositioner With Electrothermal Actuator for Decoupled Motion

2011 ◽  
Author(s):  
Yong-Sik Kim ◽  
Nicholas G. Dagalakis ◽  
Satyandra K. Gupta
Keyword(s):  
Design Concept ◽  
Degree Of Freedom ◽  
Motion Platform ◽  
Element Analysis ◽  
Electrothermal Actuators ◽  
Electrothermal Actuator ◽  
Decoupled Motion ◽  
Moving Platform ◽  
Two Degree Of Freedom ◽  
Novel Design

Building a two degree-of-freedom (2 DOF) MEMS nanopositioner with decoupled X-Y motion has been a challenge in nanopositioner design. In this paper a novel design concept on making the decoupled motion of the MEMS nanopositioner is suggested. The suggested nanopositioner has two electrothermal actuators and employs a fully nested motion platform with suspended anchors. The suggested MEMS nanopositioner is capable of delivering displacement from the electrothermal actuator to the motion platform without coupled motion between the two X-Y axes. The design concept, finite element analysis (FEA) results, fabrication procedures and the performance of the 2 DOF nanopositioner is presented. In order to test the nanopositioner moving platform decoupled motion, one actuator moves the platform by 60 μm, while the other actuator is kept at the same position. The platform position cross talk error was measured to be less than 1 μm standard deviation.

An Efficient 2D Finite Element Procedure for the Quenching Analysis With Phase Change

1993 ◽  
Vol 115 (1) ◽  
pp. 124-138 ◽  
Author(s):  
K. F. Wang ◽  
S. Chandrasekar ◽  
H. T. Y. Yang
Keyword(s):  
Finite Element ◽  
Phase Changes ◽  
Age Hardening ◽  
Infinite Cylinder ◽  
Temperature Dependent ◽  
Element Analysis ◽  
Practical Applications ◽  
Mixed Hardening ◽  
Wide Range ◽  
Finite Element Procedure

An efficient finite element procedure has been developed for the analysis of quenching problems involving nonisothermal phase changes. The finite element analysis includes temperature dependent material properties, a mixed hardening rule to describe the material constitutive model, and the incorporation of time-temperature-transformation (TTT) diagrams. The procedure is applied to the simulation of quenching of steel cylinders and an aluminum connector with temperature-dependent convection boundary conditions. First, the stress analysis of the quenching of an infinite cylinder is carried out and the predicted distributions of temperature and stresses are compared with an available numerical solution to validate the accuracy of the present formulation and procedure. To demonstrate the predictive capability and practical applicability of the developed procedure, the simulation of quenching of finite cylinders of various length-to-diameter ratios and of a square bar are presented. The role of edge effects and specimen geometry on the residual stress distribution is analyzed. In addition, the microstructures developed during the quenching of 1080 carbon steel cylinders are predicted using TTT diagram incorporated in the analysis. The final example addresses the simulation of age hardening in spray quenched 2024 aluminum connector. The example problems are directly related to many practical applications, such as the heat-treatment of solid piston pins used in automotive engines and the spray quenching of aluminum connector. They also illustrate the wide range of material transformations which can be modeled using the present finite element procedure.

scholarly journals Displacement amplification ratio modeling of bridge-type nano-positioners with input displacement loss

2019 ◽  
Vol 10 (1) ◽  
pp. 299-307
Author(s):  
Jinyin Li ◽  
Peng Yan ◽  
Jianming Li
Keyword(s):  
Experimental Testing ◽  
Elastic Beam ◽  
Beam Theory ◽  
Element Analysis ◽  
Compliance Matrix ◽  
Amplification Ratio ◽  
Practical Applications ◽  
Analysis And Design ◽  
Proposed Model ◽  
Bridge Type

Abstract. This paper presents an improved modeling method for bridge-type mechanism by taking the input displacement loss into consideration, and establishes an amplification ratio model of bridge-type mechanism according to compliance matrix method and elastic beam theory. Moreover, the amplification ratio of the designed bridge-type nano-positioner is obtained by taking the guiding mechanism as the external load of bridge-type mechanism. Comparing with existing methods, the proposed model is more accurate, which is further verified by finite element analysis(FEA) and experimental test. The consistency of the results obtained from theoretical model, FEA and experimental testing indicates that the proposed model can accurately predict the amplification characteristics of nano-positioners, which helps the analysis and design of bridge-type nano-positioners in practical applications.

scholarly journals Mechanical Characterization and Finite Element Analysis of Jute-Epoxy Composite

2018 ◽  
Vol 144 ◽  
pp. 02014 ◽  
Author(s):  
Rajole Sangamesh ◽  
Naveen Kumar ◽  
K. S. Ravishankar ◽  
S. M. Kulkarni
Keyword(s):  
Composite Materials ◽  
Mechanical Characterization ◽  
Natural Fiber ◽  
Fiber Composite ◽  
High Strength ◽  
Sem Analysis ◽  
Element Analysis ◽  
Practical Applications ◽  
The Matrix ◽  
Natural Fiber Composite

Natural fiber composite materials are such an appropriate material, that replaces synthetic composite materials for many of practical applications where we need high strength and low density. Natural fiber composites combine the technological, ecological and economical aspects. This leads to discovering its vast applications in the aeronautics, automotive, marine and sporting sectors. This paper deals with the study on mechanical characterization (Tensile, Compression and Flexural) of jute/epoxy (JE) polymer composite. The flexural properties of composites are experimentally tested and are simulated in commercially available FEA software. Flexural tested results are in good agreement with FEA results. Scanning electron microscopy (SEM) analysis of the failed samples reveals the matrix dominated failure.

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