scholarly journals Numerical and Experimental Modal Analysis Applied to an Optical Test System Designed for the Form Measurements of Metre-Scale Optics

2018 ◽  
Vol 2018 ◽  
pp. 1-14
Author(s):  
P. G. Golanó ◽  
L. Zanotti Fragonara ◽  
P. Morantz ◽  
R. Jourdain
Keyword(s):  
Modal Analysis ◽  
Dynamic Range ◽  
Design Feature ◽  
Test System ◽  
Element Analysis ◽  
Measurement Capability ◽  
Fea Model ◽  
Natural Modes ◽  
Investigation Methods ◽  
Optical Test

The work focuses on the structural design and performances of a unique optical test system (OTS) used for measuring metre-scale optical surfaces. The investigation was carried out through a modal analysis. Two sets of results are presented. Both modal analysis of the entire OTS and transmissibility function related to its use as an optical system are carried out and analysed. The OTS is used for the measurements of the form accuracy at nanometre level of metre-scale concave surfaces. The OTS is a four and half-metre-tall mechanical structure made of bolted aluminium profiles, two structural platens, two dedicated precision positioning supports, a test piece, and a state-of-the-art laser interferometer. The OTS was numerically modelled and fully instrumented with triaxial accelerometers. The results of the modal analysis highlight the natural modes of the entire OTS. Both numerical and experimental methods are designed. The investigation methods are iterative. Indeed, a preliminary numerical model is created using finite element analysis (FEA). FEA results enable the determination of the dynamic range and suitable locations of accelerometers that are mounted onto the OTS for the experimental validation of the FEA model and further to carry out the transmissibility study. Natural frequencies, damping ratios, and mode shape values are obtained and scrutinized. These results are used for refining the FEA model. In fact, the lack of symmetry and the use of feet are identified as the key design feature that affects the OTS. The correlation between experimental and numerical results is within five percent for the first four modes. The results of the transmissibility study highlight the specific natural modes that influence the OTS measurement capability. Overall, the study enables to guide engineers and researchers towards a robust design using a validated and methodical approach.

Finite Element Analysis Based on ANSYS of Bolt of Roof Bolter

2014 ◽  
Vol 926-930 ◽  
pp. 3042-3045
Author(s):  
Si Cong Yuan ◽  
Xin Guo ◽  
Xiao Yu Wang ◽  
Xi Yong Pei
Keyword(s):  
Modal Analysis ◽  
Static Analysis ◽  
Three Dimensional ◽  
Structure Design ◽  
Element Analysis ◽  
Shaft Diameter ◽  
Natural Modes ◽  
Roof Bolter ◽  
Solid Models ◽  
Reasonable Choice

The three-dimensional solid models of five different length and shaft diameter anchor of bolt were constructed based on ANSYS software, and making static analysis and modal analysis on it to obtain the stress nephogram and natural frequency of bolt. Research on the stress condition of bolt in static analysis. In modal analysis, researching on the effect regular of the change of length and shaft diameter size on the bolt transverse vibration, the longitudinal and torsional vibration of three natural modes of different frequency, providing a reference for the structure design and reasonable choice of bolt type for corresponding condition.

Experimental and Finite Element Analysis of Natural Modes and Frequencies of Hollow Fan Blades

2013 ◽  
Vol 467 ◽  
pp. 306-311 ◽  
Author(s):  
M. Nikhamkin ◽  
B. Bolotov
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Vibration Modes ◽  
Element Analysis ◽  
Turbine Engine ◽  
Natural Modes ◽  
Resonance Vibrations ◽  
Super Plastic ◽  
Fan Blade ◽  
Scanning Laser Vibrometry

Natural modes and frequencies of gas turbine engine hollow fan blades were experimentally investigated. The blades were produced with the method of super-plastic molding and pressure welding combination. Two independent experimental methods were used: three-component scanning laser vibrometry and impact modal analysis. Natural frequencies and vibration modes of a hollow fan blade and stress fields corresponding to the natural modes were got. The finite element modal analysis was carried out. The hollow fan blade was stated to have particular natural vibration modes. The investigation results can be used to detune the resonance vibrations and to verify calculation models.

scholarly journals Stress Relaxation of a Sport Utility Vehicle Chassis Using a Dynamic Force Counteracting Approach

2018 ◽  
Vol 249 ◽  
pp. 03001 ◽  
Author(s):  
Wenlin Wang ◽  
Zhichao Hou ◽  
Zirong Zhou ◽  
Siyuan Cheng
Keyword(s):  
Stress Relaxation ◽  
Modal Analysis ◽  
Torsional Stiffness ◽  
Dynamic Force ◽  
Sport Utility Vehicle ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Fea Model ◽  
Utility Vehicle ◽  
Excessive Stress

Structural failures in a Chinese sport utility vehicle (SUV) Land-wind X6 chassis were reported in recent years, thus, it is meaningful to conduct trouble-shooting and effective optimization to improve the chassis. Stress relaxation of the Land-wind X6 chassis using a novel dynamic force counteracting approach was carried out in this study. Finite Element Analysis (FEA) model of the chassis was firstly established and theoretical modal analysis was performed using the FEA model, experimental modal analysis was followed to validate the theoretical modal analysis and the FEA model. Further static and local stress analyses demonstrate that irrational designs between the longitudinal beams and the suspension components lead to inadequate stiffness and excessive stress concentrations which would cause fatigue and structural failure when the SUV chassis is subject to complex and severe excitations. A novel dynamic forces counteracting approach was introduced to optimize the chassis structure, FEA results show that excessive stress concentrations were obviously eliminated and the chassis stiffness, especially the torsional stiffness was greatly improved after optimization, followed industrial implementation also verifies that the FEA-based study and product optimization performed in this work are successful and significant.

Predicting the Natural Frequency of Train Structures Using Detailed Finite Element Models

2016 ◽  
Author(s):  
Robert A. MacNeill ◽  
Glenn Gough
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Natural Frequency ◽  
Natural Frequencies ◽  
Holistic Approach ◽  
Light Rail ◽  
Element Analysis ◽  
Fea Model ◽  
High Level ◽  
Structural Mass

Train carbody and truck structures are designed to exhibit primary natural frequency modes great enough to avoid unwanted resonant oscillations with normal track interactions. Critical bounce modes can be excited by typical track in the 2–4 Hz range. Trains are designed with first modes above this threshold. Historically, simplified approaches are employed to predict natural frequencies of the main truck and carbody train structures independently. Since the advent of high powered computing, more detailed finite element analysis (FEA) eigenvalue approaches have been used to more accurately predict natural frequency of structures. Still, the typical FEA approach uses simplified boundary conditions and partial models to determine natural frequencies of individual components, neglecting the interaction with other connected structures. In this paper, a detailed, holistic approach is presented for an entire Light Rail Vehicle (LRV). The analysis is performed on a fully detailed FEA model of the LRV, including trucks and suspension, carbody structures, non-structural mass, articulation, as well as intercar and truck-carbody connections. The model was developed for detailed crashworthiness investigations, which requires a high level of fidelity compared to what is typically required for static and modal analysis. Using the same model for multiple purposes speeds up development while also improving the accuracy of the analyses. In this paper, the modal analysis methodology developed is described. A case study is presented investigating the often neglected contribution of windows, cladding, and flooring on the overall carbody natural frequency.

Modal Test and Finite Element Analysis of Sand Blender’s Agitator

2010 ◽  
Vol 139-141 ◽  
pp. 2359-2363
Author(s):  
Jian Hua ◽  
Si Zhu Zhou ◽  
Jun Qiao Wang ◽  
Fu Ping Zhong ◽  
Xiao Xia Wei
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Modal Analysis ◽  
Dynamic Characteristic ◽  
Great Influence ◽  
Test System ◽  
System Structure ◽  
Frequency Error ◽  
Element Analysis ◽  
Modal Test

Agitator as a key component of fracturing unit, its dynamic characteristic has great influence on performance of fracturing fluid and operation of sand blender, so it is necessary to get the dynamic characteristic of agitator. In this study, we conduct the experimental modal test of agitator by using uTeKL dynamic signal analysis system. The modal test system structure, the procedure and the technique of modeling and testing is presented in detail. Also the finite element modal analysis of agitator is carried out with SolidWorks software. Modal test and finite element analysis reveal similar results with the maximum natural frequency error is 5.15% and corresponding modal shapes are nearly same, which means the method and technique of modal test proposed in this paper is correct, the result is confident, and the finite element modal analysis of the agitator is feasible.

Modal Analysis of a Vertically Tapered Frame

2017 ◽  
Vol 17 (03) ◽  
pp. 1771001
Author(s):  
M. L. Chandravanshi ◽  
A. K. Mukhopadhyay
Keyword(s):  
Modal Analysis ◽  
Force Transducer ◽  
Modal Parameters ◽  
Response Functions ◽  
Element Analysis ◽  
Fea Model ◽  
The Finite Element Analysis ◽  
Convergence Study ◽  
Probable Failure ◽  
Ansys Workbench

The paper delineates the procedure to assess probable failure sections through the dynamic conditions of a vertically tapered frame using the experimental modal analysis (EMA), which is validated through the finite element analysis (FEA). The modal parameters are experimentally determined by the frequency response functions (FRFs) using the accelerometer, force transducer, electro-dynamic shaker, dynamic signal analyzer (DSA) and post processed by the ME’Scope software. The ANSYS Workbench 14 was used for finding the modal parameters through the FEA. The FEA model was also tested by convergence study. The boundary conditions of the vertically tapered frame in the FEA is kept similar to the EMA. The values obtained by the two methods have been compared for their proximity.

Strength and Modal Analysis on Welded Bracket of the Large-Scale Agitator

2007 ◽  
Vol 345-346 ◽  
pp. 1485-1488
Author(s):  
Li Gang Qu ◽  
Da Wei Wu
Keyword(s):  
Modal Analysis ◽  
Large Scale ◽  
Structural Complexity ◽  
Strength Criterion ◽  
Risk Area ◽  
Element Analysis ◽  
Functional Roles ◽  
3D Cad ◽  
Fea Model ◽  
Set Up

The welded bracket is an important supporting component with the structural complexity and crucial functional roles in a large-scale agitator. Strength and modal analysis on it are carried out with the finite element analysis software COSMOS/DesignStar according to the equipment’s working behaviours in presence of rational FEA model of the welded bracket being created with 3D CAD software SolidWorks. The conclusion is made from analysis results that the strength criterion is satisfied with operating requirement of the equipment, and the risk area of the tensile stress is explored, moreover, the dangerous natural frequencies are 41Hz and 95Hz which are worked out respectively through modal analysis results. This analysis process is significant for the agitator design. The technique foundation and method are not only set up effectively, but also the utilized data is provided for the product design and successive manufacturing. The lead time of the agitator will be shortened, and the product quality will be improved.

Tire Cornering Simulation Using an Explicit Finite Element Analysis Code

1998 ◽  
Vol 26 (2) ◽  
pp. 109-119 ◽  
Author(s):  
M. Koishi ◽  
K. Kabe ◽  
M. Shiratori
Keyword(s):  
Finite Element Method ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Test System ◽  
Experimental Results ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Explicit Finite Element ◽  
Explicit Finite Element Analysis ◽  
Element Method

Abstract The finite element method has been used widely in tire engineering. Most tire simulations using the finite element method are static analyses, because tires are very complex nonlinear structures. Recently, transient phenomena have been studied with explicit finite element analysis codes. In this paper, the authors demonstrate the feasibility of tire cornering simulation using an explicit finite element code, PAM-SHOCK. First, we propose the cornering simulation using the explicit finite element analysis code. To demonstrate the efficiency of the proposed simulation, computed cornering forces for a 175SR14 tire are compared with experimental results from an MTS Flat-Trac Tire Test System. The computed cornering forces agree well with experimental results. After that, parametric studies are conducted by using the proposed simulation.

Tire Bead Overheating in Urban Buses and Trucks Using Drum Brake Systems

1998 ◽  
Vol 26 (1) ◽  
pp. 51-62
Author(s):  
A. L. A. Costa ◽  
M. Natalini ◽  
M. F. Inglese ◽  
O. A. M. Xavier
Keyword(s):  
Heat Transfer ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Thermal Energy ◽  
Structural Integrity ◽  
Experimental Temperature ◽  
Temperature Profiles ◽  
Element Analysis ◽  
Drum Brake ◽  
Fea Model

Abstract Because the structural integrity of brake systems and tires can be related to the temperature, this work proposes a transient heat transfer finite element analysis (FEA) model to study the overheating in drum brake systems used in trucks and urban buses. To understand the mechanics of overheating, some constructive variants have been modeled regarding the assemblage: brake, rims, and tires. The model simultaneously studies the thermal energy generated by brakes and tires and how the heat is transferred and dissipated by conduction, convection, and radiation. The simulated FEA data and the experimental temperature profiles measured with thermocouples have been compared giving good correlation.

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