scholarly journals Empirical method for structural damage location using dynamic analysis

2020 ◽  
Vol 13 (1) ◽  
pp. 19-31
Author(s):  
R. L. SILVA ◽  
L. M. TRAUTWEIN ◽  
C. S. BARBOSA ◽  
L. C. ALMEIDA ◽  
G. H. SIQUEIRA
Keyword(s):  
Finite Element ◽  
Structural Damage ◽  
Empirical Method ◽  
Finite Element Models ◽  
Simply Supported ◽  
Damage Location ◽  
Acceleration Amplitude ◽  
Modal Curvature ◽  
The Difference ◽  
Rubber Bearings

Abstract This paper presents the use of numerical model techniques for identification and damage location adopting the Modal Curvature Difference (MCD) method as reference for the analysis of a simply supported concrete structure. Then, an empirical formulation to detect damages in this structure is proposed. In this method, called Acceleration Summation Difference (ASD), the difference of acceleration amplitude between intact and damaged structures are calculated for concrete plates simply supported on rubber bearings. During the analyses, the finite element models were developed using SAP2000® software. The results obtained depicted that it is possible to determine the approximate position of one or more damages in the structure, with some restrictions, and the proposed ASD method presented good correlation to localize the position of single or multiple damages.

Vibration-Based Damage Detection and Seismic Performance Assessment of Bridges

2015 ◽  
Vol 31 (1) ◽  
pp. 137-157 ◽  
Author(s):  
Ekin Özer ◽  
Serdar Soyöz
Keyword(s):  
Finite Element ◽  
Damage Detection ◽  
Structural Damage ◽  
Fragility Curves ◽  
Reliability Estimation ◽  
Concrete Bridge ◽  
Finite Element Models ◽  
Seismic Performance Assessment ◽  
Reinforced Concrete Bridge ◽  
The Difference

This paper proposes a reliability estimation methodology which utilizes system identification results obtained from vibration measurements. A series of earthquake and white noise excitations are imposed to a three-bent reinforced concrete bridge by three-shaking tables, simultaneously. Progressive structural damage is measured and observed, in accordance with increasing intensities of damaging events. Response measurements are obtained by accelerometers located on the deck and the columns of the bridge. Finite element models for non-updated and updated cases were obtained with and without considering acceleration measurements, respectively. Afterwards, damage detection and reliability estimation were carried out for these two cases using fragility curves. Consequently, it is shown that fragility curves of updated models significantly differ from fragility curves of non-updated models. The distinction stems from the difference between stiffness and especially damping parameters of updated and non-updated models. Such difference becomes more prominent at the extreme levels of damage.

Comparison of Two Approaches to Model Cure-Induced Microcracking in Three-Dimensional Woven Composites

2012 ◽  
Author(s):  
Igor Tsukrov ◽  
Michael Giovinazzo ◽  
Kateryna Vyshenska ◽  
Harun Bayraktar ◽  
Jon Goering ◽  
...  
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Woven Composites ◽  
Finite Element Models ◽  
The Matrix ◽  
3D Woven Composites ◽  
The Difference ◽  
Resin Curing

Finite element models of 3D woven composites are developed to predict possible microcracking of the matrix during curing. A specific ply-to-ply weave architecture for carbon fiber reinforced epoxy is chosen as a benchmark case. Two approaches to defining the geometry of reinforcement are considered. One is based on the nominal description of composite, and the second involves fabric mechanics simulations. Finite element models utilizing these approaches are used to calculate the overall elastic properties of the composite, and predict residual stresses due to resin curing. It is shown that for the same volume fraction of reinforcement, the difference in the predicted overall in-plane stiffness is on the order of 10%. Numerical model utilizing the fabric mechanics simulations predicts lower level of residual stresses due to curing, as compared to nominal geometry models.

Structural Damage Detection Depending on Curvature Matrix of Change in Flexibility

2011 ◽  
Vol 255-260 ◽  
pp. 389-393
Author(s):  
Yong Mei Li ◽  
Bin Zhou ◽  
Xi Yuan Zhou ◽  
Guo Fu Sun ◽  
Bo Yan Yang
Keyword(s):  
Numerical Simulation ◽  
Damage Detection ◽  
Cantilever Beam ◽  
Lower Order ◽  
Structural Damage ◽  
Structural Damage Detection ◽  
Principal Diagonal ◽  
Simply Supported ◽  
Damage Location ◽  
Difference Calculation

Flexibility is more sensitive to structural damage than frequency or mode. Curvature matrix of change in flexibility is presented as a new index of nondestructive damage detection, which is derived from change in structural flexibilities calculated from before damaging and after damaging by means of difference calculation twice, firstly to columns, and then to rows. Therefore a new indicator called as δ Flexibility Curvature Matrix Diagonal (δFCMD) is constructed from the principal diagonal elements based on curvature matrix of change in flexibility. The numerical simulation examples indicate that the damage location and severity in structures, with single damage, multiple ones, slight ones and ones at the supports, can be detected efficiently for a cantilever beam, a fixed supported beam, a simply supported beams and so on by the indicator of δFCMD depending on only a few of lower order modes.

Enhanced Design Criteria for Offshore Pipeline Integral Buckle Arrestors

2008 ◽  
Author(s):  
L.-H. Lee ◽  
S. Kyriakides ◽  
T. A. Netto
Keyword(s):  
Finite Element ◽  
Thick Wall ◽  
Design Criteria ◽  
Finite Element Models ◽  
Design Formula ◽  
Offshore Pipeline ◽  
Deformation Plasticity ◽  
The Difference ◽  
Buckle Arrestors ◽  
Empirical Design

Integral buckle arrestors are relatively thick-wall rings periodically welded in an offshore pipeline at intervals of several hundred meters in order to safeguard the line in the event a propagating buckle initiates. They provide additional circumferential rigidity and thus impede downstream propagation of collapse, limiting the damage to the length of pipe separating two arrestors. The effectiveness of such devices was studied parametrically through experiment and numerical simulations in Park and Kyriakides [2]. The experiments involved quasi-static propagation of collapse towards an arrestor, engagement of the arrestor, temporary arrest, and the eventual crossing of collapse to the downstream pipe at a higher pressure. The same processes were simulated with finite element models that included finite deformation plasticity and contact. The experimental crossover pressures enriched with numerically generated values were used to develop an empirical design formula for the arresting efficiency of such devices. A recent experimental extension of this work revealed that for some combinations of arrestor and pipe yield stresses the design formula was overly conservative. Motivated by this finding, a new broader parametric study of the problem was undertaken which demonstrated that the difference between the pipe and arrestor yield stress affects significantly the arrestor performance. The original arrestor design formula was then modified to include the new experimental and numerical results producing an expression with a much wider applicability.

Analysis of the Reasonable Construction Size of Concrete Bridge Deck

2011 ◽  
Vol 90-93 ◽  
pp. 1027-1032
Author(s):  
Xian Xi Tang ◽  
Xian Zhou Tang ◽  
Yue Xu ◽  
Wei Guo
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Bridge Deck ◽  
Bridge Decks ◽  
Concrete Bridge ◽  
Finite Element Models ◽  
Simply Supported ◽  
Concrete Bridge Deck ◽  
Beam Bridge ◽  
T Beam

In order to study the reasonable thickness and width of bridge decks of concrete T beam bridge, 36 ANSYS finite element models of simply supported concrete T beam were established, stress performance of each models have been analyzed under the centre load. The analysis results indicated that when the bridge deck thickness reached 22cm, it was no much sense of influence of bridge decks stress and deflection change by increasing the thickness of the bridge deck, therefore, the recommended value of deck thickness was about 22cm. Since the width of the bridge deck has little effect of the mechanical properties and stiffness of it, so the recommended values of the bridge decks width should be determined combined with the diaphragm and the integral stiffness of T beam bridge.

scholarly journals Assessment of Model Uncertainty in the Prediction of the Vibroacoustic Behavior of a Rectangular Plate by Means of Bayesian Inference

2021 ◽  
pp. 264-277
Author(s):  
Nikolai Kleinfeller ◽  
Christopher M. Gehb ◽  
Maximilian Schaeffner ◽  
Christian Adams ◽  
Tobias Melz
Keyword(s):  
Boundary Condition ◽  
Finite Element ◽  
Bayesian Inference ◽  
Boundary Conditions ◽  
Model Uncertainty ◽  
Prediction Error ◽  
Finite Element Models ◽  
Simply Supported ◽  
Thin Walled Structures ◽  
Thin Walled

AbstractDesigning the vibroacoustic properties of thin-walled structures is of particularly high practical relevance in the design of vehicle structures. The vibroacoustic properties of thin-walled structures, e.g., vehicle bodies, are usually designed using finite element models. Additional development effort, e.g., experimental tests, arises if the quality of the model predictions are limited due to inherent model uncertainty. Model uncertainty of finite element models usually occurs in the modeling process due to simplifications of the geometry or boundary conditions. The latter highly affect the vibroacoustic properties of a thin-walled structure. The stiffness of the boundary condition is often assumed to be infinite or zero in the finite element model, which can lead to a discrepancy between the measured and the calculated vibroacoustic behavior. This paper compares two different boundary condition assumptions for the finite element (FE) model of a simply supported rectangular plate in their capability to predict the vibroacoustic behavior. The two different boundary conditions are of increasing complexity in assuming the stiffness. In a first step, a probabilistic model parameter calibration via Bayesian inference for the boundary conditions related parameters for the two FE models is performed. For this purpose, a test stand for simply supported rectangular plates is set up and the experimental data is obtained by measuring the vibrations of the test specimen by means of scanning laser Doppler vibrometry. In a second step, the model uncertainty of the two finite element models is identified. For this purpose, the prediction error of the vibroacoustic behavior is calculated. The prediction error describes the discrepancy between the experimental and the numerical data. Based on the distribution of the prediction error, which is determined from the results of the probabilistic model calibration, the model uncertainty is assessed and the model, which most adequately predicts the vibroacoustic behavior, is identified.

Non-linear normal modes of a simply supported beam: continuous system and finite-element models

2004 ◽  
Vol 82 (31-32) ◽  
pp. 2683-2691 ◽  
Author(s):  
Carlos E.N. Mazzilli ◽  
Mário E.S. Soares ◽  
Odulpho G.P. Baracho Neto
Keyword(s):  
Finite Element ◽  
Normal Modes ◽  
Continuous System ◽  
Finite Element Models ◽  
Simply Supported Beam ◽  
Simply Supported ◽  
Non Linear

Assessment of Damage Affecting All Structural Properties Using Experimental Modal Parameters

2000 ◽  
Vol 122 (4) ◽  
pp. 456-463 ◽  
Author(s):  
Mohamed Kaouk ◽  
David C. Zimmerman ◽  
Todd W. Simmermacher
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Structural Damage ◽  
Element Model ◽  
Modal Parameters ◽  
Eigenvalues And Eigenvectors ◽  
Minimum Rank ◽  
Damage Location ◽  
Damage Extent ◽  
Stiffness And Damping

Recently, the authors proposed computationally attractive algorithms to determine the location and extent of structural damage for undamped and damped structures assuming damage results in a localized change in a subset (not full set) of the property matrices (mass, stiffness and damping matrices). The algorithms make use of a finite element model and a subset of measured eigenvalues and eigenvectors. The developed theories approach the damage location and extent problem in a decoupled fashion. First, a theory is developed to determine the location of structural damage. With location determined, a damage extent theory is then developed. The damage extent algorithm is a minimum rank perturbation, which is consistent with the effects of many classes of structural damage on a finite element model. In this work, the concept of the Minimum Rank Perturbation Theory (MRPT) is adopted to simultaneously determine the damage extent of all property matrices of undamped and proportionally damped structures. Note that the property matrices are the mass, stiffness and damping matrices. Illustrative examples are presented to show the performance of the proposed theory. [S0739-3717(00)01904-8]

scholarly journals Dynamic Identification Techniques to Numerically Detect the Structural Damage

2013 ◽  
Vol 7 (1) ◽  
pp. 43-50 ◽  
Author(s):  
Dora Foti
Keyword(s):  
Finite Element ◽  
Damage Detection ◽  
Structural Damage ◽  
Model Updating ◽  
Element Model ◽  
Mode Shapes ◽  
Dynamic Identification ◽  
Engineering Structures ◽  
Bridge Model ◽  
Modal Curvature

Damage detection in civil engineering structures using changes in measured modal parameters is an area of research that has received notable attention in literature in recent years. In this paper two different experimental techniques for predicting damage location and severity have been considered: the Change in Mode Shapes Method and the Mode Shapes Curvature Method. The techniques have been applied to a simply supported finite element bridge model in which damage is simulated by reducing opportunely the flexural stiffness EI. The results show that a change in modal curvature is a significant damage indicator, while indexes like MAC and COMAC – extensively and correctly used for finite element model updating - lose their usefulness in order to damage detection.

Sign in / Sign up

Export Citation Format

Share Document