scholarly journals Experimental Study for Damage Identification of Storage Tanks by Adding Virtual Masses

Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 220 ◽  
Author(s):  
Jilin Hou ◽  
Pengfei Wang ◽  
Tianyu Jing ◽  
Łukasz Jankowski
Keyword(s):  
Experimental Study ◽  
Finite Element ◽  
Frequency Response ◽  
Response Function ◽  
Storage Tank ◽  
Frequency Response Function ◽  
Damage Identification ◽  
Fe Model ◽  
Storage Tanks ◽  
Identification Approach

This research proposes a damage identification approach for storage tanks that is based on adding virtual masses. First, the frequency response function of a structure with additional virtual masses is deduced based on the Virtual Distortion Method (VDM). Subsequently, a Finite Element (FE) model of a storage tank is established to verify the proposed method; the relation between the added virtual masses and the sensitivity of the virtual structure is analyzed to determine the optimal mass and the corresponding frequency with the highest sensitivity with respect to potential damages. Thereupon, the damage can be localized and quantified by comparing the damage factors of substructures. Finally, an experimental study is conducted on a storage tank. The results confirm that the proposed method is feasible and practical, and that it can be applied for damage identification of storage tanks.

Damage identification using structural modes based on substructure virtual distortion method

2016 ◽  
Vol 20 (2) ◽  
pp. 257-271 ◽  
Author(s):  
Qingxia Zhang ◽  
Łukasz Jankowski
Keyword(s):  
Frequency Response ◽  
Response Function ◽  
Structural Damage ◽  
Frequency Response Function ◽  
Damage Identification ◽  
Element Model ◽  
Frequency Responses ◽  
Computational Work ◽  
Structural Reanalysis ◽  
Identification Approach

A damage identification approach is presented using substructure virtual distortion method which takes the advantage of the fast structural reanalysis technique of virtual distortion method. The formulas of substructure virtual distortion method are deduced in frequency domain, and then the frequency response function of the damaged structure is constructed quickly via the superposition of the frequency response function of the intact structure and the frequency responses caused by the damage-coupling virtual distortions of the substructures. The structural damage extents are identified using the measured modal parameters. Two steps are adopted to increase the efficiency of optimization: the modals of finite element model are estimated quickly from the fast constructed frequency response function during the optimization and the primary distortions of the substructures are extracted by contribution analysis to further reduce the computational work. A six-story frame numerical model and an experiment of a cantilever beam are carried out, respectively, to verify the efficiency and accuracy of the proposed method.

An Identification Approach of Dynamic Contact Parameters for Toolholder-Spindle Joint Base on Frequency Response Function

2012 ◽  
Vol 538-541 ◽  
pp. 748-753
Author(s):  
Guo Ping An ◽  
Xin Yu Liu ◽  
Yong Sheng Zhao ◽  
Li Gang Cai
Keyword(s):  
Frequency Response ◽  
Response Function ◽  
Frequency Response Function ◽  
Dynamic Contact ◽  
Work Piece ◽  
Spindle System ◽  
Manufacturing Efficiency ◽  
Identification Approach ◽  
Contact Parameters

The joint of the toolholder-spindle is the most weakness structure in the system of toolholder-spindle. It affects the manufacturing efficiency and the surface quality of work piece. It is important to identify the dynamic contact parameters for evaluating the connectivity of the toolholder-spindle system. The article introduces an approach to identify the dynamic contact parameters of toolholder-spindle joint base on frequency response function (FRF). Using the BT40 toolholder-spindle system, we can get the dynamic contact parameters curve of toolholder-spindle by the previous approach. The translational and rotational contact parameters can be obtained by sensitivity analysis. By comparing the simulation results with those of experimentation, it can prove the validity of identified dynamic contact parameters. The research results can provide a theoretical basis for the optimization of toolholder.

Change of modal parameters due to crack growth in a tripod tower platform

1993 ◽  
Vol 20 (5) ◽  
pp. 801-813 ◽  
Author(s):  
Yin Chen ◽  
A. S. J. Swamidas
Keyword(s):  
Finite Element ◽  
Frequency Response ◽  
Response Function ◽  
Frequency Response Function ◽  
Experimental Results ◽  
Modal Testing ◽  
Modal Parameters ◽  
Response Functions ◽  
Frequency Response Functions ◽  
Strain Frequency

Strain gauges, along with an accelerometer and a linear variable displacement transducer, were used in the modal testing to detect a crack in a tripod tower platform structure model. The experimental results showed that the frequency response function of the strain gauge located near the crack had the most sensitivity to cracking. It was observed that the amplitude of the strain frequency response function at resonant points had large changes (around 60% when the crack became a through-thickness crack) when the crack grew in size. By monitoring the change of modal parameters, especially the amplitude of the strain frequency response function near the critical area, it would be very easy to detect the damage that occurs in offshore structures. A numerical computation of the frequency response functions using finite element method was also performed and compared with the experimental results. A good consistency between these two sets of results has been found. All the calculations required for the experimental modal parameters and the finite element analysis were carried out using the computer program SDRC-IDEAS. Key words: modal testing, cracking, strain–displacement–acceleration frequency response functions, frequency–damping–amplitude changes.

Study on Benchmark Structure Damage Identification Base on Frequency Response Function and Genetic Algorithm

2010 ◽  
Vol 163-167 ◽  
pp. 2765-2769 ◽  
Author(s):  
Wan Jie Zou ◽  
Zhen Luo ◽  
Guo En Zhou
Keyword(s):  
Genetic Algorithm ◽  
Frequency Response ◽  
Response Function ◽  
Frequency Response Function ◽  
Damage Identification ◽  
Fitness Function ◽  
Floating Point ◽  
Combined Method ◽  
Structure Damage ◽  
Floating Point Number

A combined method for the Benchmark structure damage identification base on the frequency response function(FRF) and genetic algorithm(GA) is presented. The reducing factors of element stiffness are used as the optimization variables, and the cross signature assurance criterion (CSAC) of the test FRF and the analysis FRF is used to constructing the optimization object function and the fitness function of the GA. To avoid the weakness of binary encoding, the floating point number encoding is used in the GA. At last, the Benchmark structure established by IASC-ASCE SHM group is caculated by the proposed method, the results show that even if the serious testing noise is considered, the patterns of damage of the Benchmark structure can be identified well. The effectiveness of the presented method is verified.

Estimating Rotational Frequency Response Function Using Mode Expansion and Frequency Response Function Synthesis Method

2021 ◽  
Vol 18 (2) ◽  
Author(s):  
W.I.I. Wan Iskandar Mirza ◽  
Muhamad Norhisham Bin Abdul Rani ◽  
M.A. Yunus ◽  
D. Stancioiu ◽  
V. Shripathi
Keyword(s):  
Frequency Response ◽  
Response Function ◽  
Frequency Response Function ◽  
Synthesis Method ◽  
Expansion Method ◽  
Rotational Frequency ◽  
Attractive Alternative ◽  
Fe Model ◽  
System Reduction ◽  
Modal Model

The rotational frequency response function (RFRF) plays a crucial role in increasing the accuracy of the calculated results of the frequency-based substructuring method. However, RFRFs are often omitted due to the difficulties in the measurement process and limitations of the equipment. This paper presents a scheme of estimating the rotational FRF of an irregular plate structure using the FE model reduction and expansion method. The reduced FE model was introduced using the improved reduction system (IRS) and expanded to the experimental modal model (EMA model) using the system reduction and the expansion (SEREP) method. The FRF expanded method was then employed to derive the translational and rotational FRFs from the expanded EMA model. The accuracy of the expanded FRFs was evaluated with the EMA model of the irregular plate. It was found that the translational and rotational FRFs estimated from the proposed scheme were in good agreement with the EMA counterparts. Furthermore, the patterns of the estimated RFRFs were well correlated with the EMA RFRFs. This work shows that the proposed scheme may offer an attractive alternative way of accurately determining the RFRs of complex structures or structural components.

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