scholarly journals The Elastic Contact and Stability Analysis of an Inertial Micro-Switch with a Spring Stationary Electrode

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4238
Author(s):  
Wenguo Chen ◽  
Huiying Wang ◽  
Dejian Kong ◽  
Shulei Sun
Keyword(s):  
Finite Element ◽  
Contact Time ◽  
Contact Process ◽  
Experimental Tests ◽  
Element Model ◽  
Elastic Contact ◽  
Element Analysis ◽  
Stability Performance ◽  
High Acceleration ◽  
Stationary Electrode

A mechanical trigger inertial micro-switch with spring stationary electrode is proposed and fabricated by surface micromachining. The elastic contact process and stability performance are evaluated through experimental tests performed using a drop hammer. The test results show that the contact time is about 110 μs and 100 μs when the threshold acceleration is 480 g and the overload acceleration is 602 g, respectively. The vibration process of the electrodes is explained through an established physical mode. The elastic contact process is analyzed and discussed by Finite Element Analysis (FEA) simulations, which indicated that the contact time is about 65 μs when the threshold acceleration is 600 g. At the same time, this result also proved that the contact time could be extended effectively by the designed spring stationary electrode. The overload acceleration (800 g) has been applied to the Finite-Element model in ANSYS, the contact process indicated that the proof mass contacted with stationary electrode three times, and there was no bounce phenomenon during contact process, which fully proved that the stable contact process can be realized at high acceleration owing to the designed elastic stationary electrode.

scholarly journals Torsional Behaviour and Finite Element Analysis of the Hybrid Laminated Composite Shafts: Comparison of VARTM with Vacuum Bagging Manufacturing Method

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Mehmet Emin Taşdelen ◽  
Mehmet Halidun Keleştemur ◽  
Ercan Şevkat
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Glass Fibers ◽  
Laminated Composite ◽  
Experimental Tests ◽  
Element Model ◽  
Performance Criteria ◽  
Fiber Types ◽  
Element Analysis ◽  
Manufacturing Method

Braided sleeve composite shafts are produced and their torsional behavior is investigated. The braided sleeves are slid over an Al tube to create very strong and rigid tubular form shafts and they are in the form of 2/2 twill biaxial fiber fabric that has been woven into a continuous sleeve. Carbon and glass fibers braided sleeves are used for the fabrication of the composite shafts. VARTM (vacuum assisted resin transfer molding) and Vacuum Bagging are the two different types of manufacturing methods used in the study. Torsional behaviors of the shafts are investigated experimentally in terms of fabrication methods and various composite materials parameters such as fiber types, layer thickness, and ply angles. Comparing the two methods in terms of the torque forces and strain angles, the shafts producing entirely carbon fiber show the highest torque capacities; however, considering the cost and performance criteria, the hybrid shaft made up of carbon and glass fibers is the optimum solution for average demanded properties. Additionally, FE (finite element) model of the shafts was created and analyzed by using ANSYS workbench environment. Results of finite element analysis are compared with the values of twisting angle and torque obtained by experimental tests.

Nonlinear Finite Element Analysis of a Threaded Pipe Connection

2004 ◽  
Author(s):  
Farzad Tasbihgoo ◽  
John P. Caffrey ◽  
Sami F. Masri
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Experimental Tests ◽  
Element Model ◽  
Nonlinear Finite Element ◽  
Mitigation Measures ◽  
Element Analysis ◽  
Nonstructural Components ◽  
Small Water ◽  
Threaded Connections

For the past several years, USC has been involved in a major research project to study the seismic mitigation measures of nonstructural components in hospitals funded by the Federal Emergency Management Agency (FEMA). It was determined that piping was the one of the most critical components affecting the functionality of a hospital following an earthquake. Consequently, a substantial effort was spent on quantifying the behavior of typical piping components. During the loading of the threaded joint, it was common to hear a loud popping sound, followed by a small water leak. It was assumed that the sound and leakage were due to the sliding of the mating pipe threads. To confirm this theory, and to provide a tool to help understand the failure mode(s) for a wide class of threaded fittings, a detailed nonlinear finite element model was constructed using MSC/NASTRAN, and correlated to the measured failures. In this paper, a simplified model is presented first to demonstrate the modeling procedure and to help understand the sliding phenomenon. Next, a symmetric half 3D model was generated for modeling the physical experiments. It is shown that the finite element analysis (FEA) of the threaded connections captures the dominant mechanism that was observed in the experimental tests.

Numerical and Experimental Study of Elastic Interaction in Bolted Flange Joints

2017 ◽  
Vol 139 (2) ◽  
Author(s):  
Linbo Zhu ◽  
Abdel-Hakim Bouzid ◽  
Jun Hong
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Elastic Interaction ◽  
Element Model ◽  
Interaction Coefficient ◽  
Pressure Vessels ◽  
Nonlinear Finite Element ◽  
Element Analysis ◽  
Bolted Flange

Bolted flange joints are widely used to connect pressure vessels and piping equipment together and facilitate their disassembly. Initial tightening of their bolts is a delicate operation because it is extremely difficult to achieve the target load and uniformity due to elastic interaction. The risk of failure due to leakage and fatigue under service loading is consequently increased. This paper presents a study on the effect of elastic interaction that is present during the tightening of bolted flange joints using three-dimensional nonlinear finite-element modeling and experimentation. The nonlinear nonelastic behavior of the gasket is taken into account in the numerical simulation. The scatter in bolt preload produced during the tightening sequence is evaluated. Based on the elastic interaction coefficient method, the initial target tightening load in each bolt for every pass is determined by using the nonlinear finite-element model to obtain a uniform preload after the final tightening pass. The validity of the finite-element analysis (FEA) is supported by experimental tests conducted on a NPS 4 class 900 weld neck bolted flange joints using fiber and flexible graphite gaskets. This study provides guidance and enhances the safety and reliability of bolted flange joints by minimizing bolt load scatter due to elastic interaction.

Frictional Analysis of MoS2 Coated Ball Bearings: A Three-Dimensional Finite Element Analysis

1997 ◽  
Vol 119 (4) ◽  
pp. 754-763 ◽  
Author(s):  
M. R. Lovell ◽  
M. M. Khonsari ◽  
R. D. Marangoni
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Element Model ◽  
Hertzian Contact ◽  
Contact Theory ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Hertzian Contact Theory

A brief review of finite element contact and friction theory is presented for low-speed bearing operations. A three-dimensional finite element model is developed to realistically characterize the friction experienced by a coated ball bearing element. The finite elements results, which are obtained for various normal loads and ball materials, are verified using Hertzian contact theory and previous experimental tests performed by the authors. From the results, general trends for the frictional behavior of coated bearing surfaces are established and implications to the field of controls, as applied to precision positioning and tracking instruments are discussed.

scholarly journals A Complete and Fast Analysis Procedure for Three-Phase Induction Motors Using Finite Element, Considering Skewing and Iron Losses

2021 ◽  
Vol 11 (5) ◽  
pp. 2428
Author(s):  
Matteo Carbonieri ◽  
Nicola Bianchi
Keyword(s):  
Finite Element ◽  
Induction Motors ◽  
Experimental Tests ◽  
Element Model ◽  
Analysis Procedure ◽  
Computational Time ◽  
Element Analysis ◽  
Fast Analysis ◽  
Iron Losses ◽  
Long Time

This paper deals with a complete finite-element analysis procedure for squirrel cage induction motors, including the presence of skewing and the iron losses evaluation. The machine is analyzed performing only magneto-static finite element analyses. Saturation phenomena are carefully considered in any operating condition, avoiding long time-stepping analyses. The synergy between analytical and finite element model leads to a rapid and precise estimation of the rotor induced current, saving computational time. Furthermore, the procedure proposed in this paper allows the motor performance to be directly derived, without the preliminary knowledge of the machine equivalent circuit. In order to complete the analysis, skewing effect is included, using the 2-D multi-slice technique, based on static simulations. Experimental tests are carried out and reported in order to verify analysis results.

Cost-Effective Method of Optimization of Stacking Sequences in the Cylindrical Composite Shells Using Genetic Algorithm

2020 ◽  
Author(s):  
Ehsan Daneshkhah ◽  
Reza Jafari Nedoushan ◽  
Davoud Shahgholian ◽  
Nima Sina
Keyword(s):  
Genetic Algorithm ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Experimental Tests ◽  
Cost Effective ◽  
Element Model ◽  
External Pressure ◽  
Element Analysis ◽  
Cost Effective Method ◽  
Critical Buckling Pressure

Buckling is one of the common destructive phenomena, which occurs in composite cylinders subjected to external pressure. In this paper, different methods to optimize stacking sequence of these cylinders are investigated. A finite element model is proposed in order to predict critical buckling pressure and the results are validated with previous experimental data. Theoretical analysis based on NASA SP‐8007 solution and the simplified equation for cylinder buckling of ASME RD-1172 are presented and discussed. The results of theoretical and finite element analysis and experimental tests are compared for both glass and carbon epoxy cylinders. Using NASA and ASME formulations, optimal laminations of cylinders in order to maximize buckling pressure, are obtained by genetic algorithm method. Suggested laminations and the values of corresponding critical buckling pressure calculated by finite element analysis, are presented and compared in various states. Obtained results show that while predicted buckling loads of finite element analysis are reliable, NASA formulation can be used in a very cost-effective method to optimize the buckling problems.

Simulation of Secondary Contact to Generate Very High Accelerations

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Stuart T. Douglas ◽  
Moustafa Al-Bassyiouni ◽  
Abhijit Dasgupta ◽  
Kevin Gilman ◽  
Aaron Brown
Keyword(s):  
Finite Element ◽  
Contact Stiffness ◽  
Experimental Tests ◽  
Element Model ◽  
Parametric Modeling ◽  
Design Parameters ◽  
Secondary Contact ◽  
Element Analysis ◽  
Secondary Impact ◽  
Very High

This paper investigates the design of a typical commercially available drop system for generating very high shock and drop accelerations. Some commercially available drop towers produce accelerations greater than 5000 G by utilizing the dynamics of secondary impact, using an attachment termed a dual mass shock amplifier (DMSA). Depending on the design, some DMSAs are capable of repeatedly generating accelerations as high as 100,000 G. The results show that a finite element model (FEM) can capture the peak acceleration for the drop tower and the DMSA within 15%. In this paper, a detailed description of the test equipment and modeling techniques is provided. The effects of different design parameters, such as table mass, spring stiffness, and programmer material properties, on the drop profile, are investigated through parametric modeling. The effects of contact parameters on model accuracy are explored, including constraint enforcement algorithms, contact stiffness, and contact damping. Simple closed-form analytic models are developed, based on the basic principles of a single impact and the dynamics of secondary impact. Model predictions are compared with test results. Details of the test methodology and simulations guidelines are provided. Detailed finite element analysis (FEA) is conducted and validated against the experimental tests and compared to the simplified theoretical simulations. Benefits in exploring FEM to simulate contact between materials can be extrapolated to different architectures and materials such that with minimal experimental validation impact acceleration can be determined.

Numerical and Experimental Study of Elastic Interaction in Bolted Flange Joints

2016 ◽  
Author(s):  
Linbo Zhu ◽  
Abdel-Hakim Bouzid ◽  
Jun Hong
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Elastic Interaction ◽  
Element Model ◽  
Pressure Vessels ◽  
Nonlinear Finite Element ◽  
Elastic Behavior ◽  
Element Analysis ◽  
Bolted Flange

Bolted flange joints are widely used to connect pressure vessels and piping equipment together and facilitate their disassembly. Initial tightening of their bolts is a delicate operation because it is extremely difficult to achieve the target load and uniformity due to elastic interaction. The risk of failure due to leakage and fatigue under service loading is consequently increased. This paper presents a study on the effect of elastic interaction that is present during the tightening of a bolted flange joints using three-dimensional nonlinear finite element modeling and experimentation. The nonlinear non-elastic behavior of the gasket is taken into account in the numerical simulation. The scatter in bolt preload produced during the tightening sequence is evaluated. Based on the elastic interaction coefficient method, the initial target tightening load in each bolt for every pass are determined by using the nonlinear finite element model to obtain a uniform preload after the final tightening pass. The validity of the FEA (Finite Element Analysis) is supported by experimental tests conducted on a NPS 4 class 900 weld neck bolted flange joints using fiber and flexible graphite gaskets. This study provides guidance and enhances the safety and reliability of bolted flange joints by minimizing bolt scatter due to elastic interaction.

КОНСТРУКТИВНО-ТЕХНОЛОГІЧНІ ОСОБЛИВОСТІ ХВОСТО-ВИХ БАЛОК СІТЧАСТОГО ТИПУ З ПОЛІМЕРНИХ КОМПО-ЗИЦІЙНИХ МАТЕРІАЛІВ ВЕРТОЛЬОТІВ ТРАНСПОРТНОЇ КАТЕГОРІЇ

2020 ◽  
pp. 15-30
Author(s):  
А. Г. Гребеников ◽  
И. В. Малков ◽  
В. А. Урбанович ◽  
Н. И. Москаленко ◽  
Д. С. Колодийчик
Keyword(s):  
Finite Element ◽  
Strain State ◽  
Layer Structure ◽  
Metal Structure ◽  
Element Model ◽  
Stress Strain ◽  
Element Analysis ◽  
Mesh Structure ◽  
Stress Strain State ◽  
Mesh Structures

The analysis of the design and technological features of the tail boom (ТB) of a helicopter made of polymer composite materials (PCM) is carried out.Three structural and technological concepts are distinguished - semi-monocoque (reinforced metal structure), monocoque (three-layer structure) and mesh-type structure. The high weight and economic efficiency of mesh structures is shown, which allows them to be used in aerospace engineering. The physicomechanical characteristics of the network structures are estimated and their uniqueness is shown. The use of mesh structures can reduce the weight of the product by a factor of two or more.The stress-strain state (SSS) of the proposed tail boom design is determined. The analysis of methods for calculating the characteristics of the total SSS of conical mesh shells is carried out. The design of the tail boom is presented, the design diagram of the tail boom of the transport category rotorcraft is developed. A finite element model was created using the Siemens NX 7.5 system. The calculation of the stress-strain state (SSS) of the HC of the helicopter was carried out on the basis of the developed structural scheme using the Advanced Simulation module of the Siemens NX 7.5 system. The main zones of probable fatigue failure of tail booms are determined. Finite Element Analysis (FEA) provides a theoretical basis for design decisions.Shown is the effect of the type of technological process selected for the production of the tail boom on the strength of the HB structure. The stability of the characteristics of the PCM tail boom largely depends on the extent to which its design is suitable for the use of mechanized and automated production processes.A method for the manufacture of a helicopter tail boom from PCM by the automated winding method is proposed. A variant of computer modeling of the tail boom of a mesh structure made of PCM is shown.The automated winding technology can be recommended for implementation in the design of the composite tail boom of the Mi-2 and Mi-8 helicopters.

Torsional Analysis of a Steel Cord-Rubber Tire Belt Structure

1996 ◽  
Vol 24 (4) ◽  
pp. 339-348 ◽  
Author(s):  
R. M. V. Pidaparti
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Composite Structures ◽  
Three Dimensional ◽  
Element Model ◽  
Torsional Stiffness ◽  
Element Analysis ◽  
Rubber Belt ◽  
Steel Cord ◽  
Torsional Analysis

Abstract A three-dimensional (3D) beam finite element model was developed to investigate the torsional stiffness of a twisted steel-reinforced cord-rubber belt structure. The present 3D beam element takes into account the coupled extension, bending, and twisting deformations characteristic of the complex behavior of cord-rubber composite structures. The extension-twisting coupling due to the twisted nature of the cords was also considered in the finite element model. The results of torsional stiffness obtained from the finite element analysis for twisted cords and the two-ply steel cord-rubber belt structure are compared to the experimental data and other alternate solutions available in the literature. The effects of cord orientation, anisotropy, and rubber core surrounding the twisted cords on the torsional stiffness properties are presented and discussed.

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