scholarly journals Numerical Simulation Based Damage Identification in Concrete

2021 ◽  
Author(s):  
Giao Vu ◽  
Jithender J. Timothy ◽  
Divya S. Singh ◽  
Leslie Saydak ◽  
Erik H. Saenger ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Damage Identification ◽  
Early Stage ◽  
Grid Method ◽  
Ultrasonic Signals ◽  
Simulation Based ◽  
Microcrack Initiation ◽  
Numerical Wave ◽  
Microcrack Growth ◽  
Damage In Concrete

High costs for the repair of concrete structures can be prevented if damage at an early stage of degradation is detected and precautionary maintenance measures are applied. To this end, we use numerical wave propagation simulations to identify simulated damage in concrete using convolutional neural networks (CNN). Damage in concrete subjected to compression is modeled at the mesoscale using the discrete element method. Ultrasonic wave propagation simulation on the damaged concrete specimens are performed using the rotated staggered finite-difference grid method. The simulated ultrasonic signals are used to train a CNN based classifier capable of classifying three different damage stages (microcrack initiation, microcrack growth and microcrack coalescence leading to macrocracks). The performance of the classifier is improved by refining the dataset via an analysis of the averaged envelope of the signal. The classifier using the refined dataset has an overall accuracy of 90%.

scholarly journals Numerical Simulation-Based Damage Identification in Concrete

Modelling ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 355-369
Author(s):  
Giao Vu ◽  
Jithender J. Timothy ◽  
Divya S. Singh ◽  
Leslie A. Saydak ◽  
Erik H. Saenger ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Damage Identification ◽  
Early Stage ◽  
Grid Method ◽  
Ultrasonic Signals ◽  
Simulation Based ◽  
Microcrack Initiation ◽  
Numerical Wave ◽  
Microcrack Growth ◽  
Damage In Concrete

High costs for the repair of concrete structures can be prevented if damage at an early stage of degradation is detected and precautionary maintenance measures are applied. To this end, we use numerical wave propagation simulations to identify simulated damage in concrete using convolutional neural networks. Damage in concrete subjected to compression is modeled at the mesoscale using the discrete element method. Ultrasonic wave propagation simulation on the damaged concrete specimens is performed using the rotated staggered finite-difference grid method. The simulated ultrasonic signals are used to train a CNN-based classifier capable of classifying three different damage stages (microcrack initiation, microcrack growth and microcrack coalescence leading to macrocracks) with an overall accuracy of 77%. The performance of the classifier is improved by refining the dataset via an analysis of the averaged envelope of the signal. The classifier using the refined dataset has an overall accuracy of 90%.

Investigation of Contact Conditions During Stamping of a Thin Plate

2020 ◽  
Author(s):  
Harshal Y. Shahare ◽  
Rohan Rajput ◽  
Puneet Tandon
Keyword(s):  
Wave Propagation ◽  
Material Properties ◽  
High Speed ◽  
Fdtd Method ◽  
Propagation Model ◽  
Transmitted Wave ◽  
Two Dimensional ◽  
Contact Conditions ◽  
Simulation Based ◽  
Difference Time

Abstract Stamping is one of the most used manufacturing processes, where real-time monitoring is quite difficult due to high speed of the mechanical press, which leads to deterioration of the accuracy of the products In the present work, a method is developed to model elastic waves propagation in solids to measure contact conditions between die and workpiece during stamping. A two-dimensional model is developed that reduces the wave propagation equations to two-dimensional equations. To simulate the wave propagation inside the die-workpiece model, the finite difference time domain (FDTD) method and modified Yee algorithm has been employed. The numerical stability of the wave propagation model is achieved through courant stability condition, i.e., Courant-Friedrichs-Lewy (CFL) number. Two cases, i.e., flat die-workpiece interface and inclined die-workpiece interface, are investigated in the present work. The elastic wave propagation is simulated with a two-dimension (2D) model of the die and workpiece using reflecting boundary conditions for different material properties. The experimental and simulation-based results of reflected and transmitted wave characteristics are compared for different materials in terms of reflected and transmitted wave height ratio and material properties such as acoustic impedance. It is found that the numerical simulation results are in good agreement with the experimental results.

scholarly journals VERIFICATION OF NUMERICAL WAVE PROPAGATION MODELS IN TIDAL INLETS

1988 ◽  
Vol 1 (21) ◽  
pp. 30 ◽  
Author(s):  
J.A. Vogel ◽  
A.C. Radder ◽  
J.H. De Reus
Keyword(s):  
Wave Propagation ◽  
Numerical Models ◽  
River Estuary ◽  
Regular Grid ◽  
Local Wind ◽  
Tidal Inlets ◽  
Propagation Models ◽  
Dutch Coast ◽  
Model Based ◽  
Numerical Wave

The performance of two numerical wave propagation models has been investigated by comparison with field data. The first model is a refractiondiffraction model based on the parabolic equation method. The second is a refraction model based on the wave action equation, using a regular grid. Two field situations, viz. a tidal inlet and a river estuary along the Dutch coast, were used to determine the influence of the local wind on waves behind an island and a breaker zone. It may be concluded from the results of the computations and measurements that a much better agreement is obtained when wave growth due to wind is properly accounted for in the numerical models. In complicated coastal areas the models perform well for both engineering and research purposes.

scholarly journals Accelerating Numerical Wave Propagation by Wavefield Adapted Meshes, Part II: Full-Waveform Inversion

2019 ◽  
Author(s):  
Solvi Thrastarson ◽  
Martin van Driel ◽  
Lion Krischer ◽  
Dirk-Philip van Herwaarden ◽  
Christian Boehm ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Waveform Inversion ◽  
Full Waveform Inversion ◽  
Full Waveform ◽  
Numerical Wave

Simulation-Supported Early Stage Design Optimisation for a Case Study of Life Cycle Oriented Buildings

2019 ◽  
Vol 887 ◽  
pp. 353-360 ◽  
Author(s):  
Sören Eikemeier ◽  
Ardeshir Mahdavi ◽  
Robert Wimmer
Keyword(s):  
Life Cycle ◽  
Architectural Design ◽  
Early Stage ◽  
Preliminary Design ◽  
Design Phase ◽  
Design Optimisation ◽  
Stage Design ◽  
Simulation Based ◽  
Early Stage Design

To reduce the energy and resource consumption in the building sector this study is focusing on a design optimisation of life cycle oriented buildings. In order to optimise the performance of the buildings and in consequence also to achieve improved results for the mandatory Austrian energy certificate a simulation-based rapid design approach is used for the early stage design phase of the buildings, in particular for the architectural design of the buildings.Methods like the Window to Wall Ratio, at the very beginning of the design process, a parametric simulation with EnergyPlus or a more detailed optimisation approach with GenOpt are integrated in this study applied to example buildings. The results are showing that the method can be used in a circular approach for improving the heating demand of the Austrian energy certificate for this case study by more than 25 % compared to the preliminary design

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