Damage Identification in Beams by Post-processing Modal Displacements and Rotations with Haar Wavelet

2021 ◽  
pp. 817-824
Author(s):  
J. V. Araújo dos Santos ◽  
H. Lopes ◽  
A. Katunin
Keyword(s):  
Damage Identification ◽  
Haar Wavelet ◽  
Post Processing

Damage Identification of Arch Bridge Based on Curvature Mode Wavelet Analysis

2012 ◽  
Vol 166-169 ◽  
pp. 1176-1179
Author(s):  
De Qing Guan ◽  
Xiao Lin Zhong ◽  
Hong Wei Ying
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Wavelet Analysis ◽  
Damage Identification ◽  
Identification Problem ◽  
Haar Wavelet ◽  
Continuous Wavelet ◽  
The Finite Element Method ◽  
Mother Wavelet ◽  
Arch Bridge

Based on the curvature modal damage identification of wavelet analysis principle, the finite element method was applied to analyze the vibration characteristics of the damaged deck arch bridge. Take Haar wavelet as the mother wavelet, through the continuous wavelet transform of curvature mode and then identified the damaged position by the maximum of wavelet coefficients. analyze the damage identification problem under three different damaged conditions (condition 1: only the arch 1 contained one damaged location; condition 2: the arch 1 and the arch 2 contained one damaged location respectively; condition 3: the arch 1 contained two damaged locations and the arch 2 contained one damaged location).This paper provided a valuable reference of damage identification and diagnosis for arch bridge.

Vibration-Based Damage Identification Using Wavelet Transform and a Numerical Model of Shearography

2019 ◽  
Vol 19 (04) ◽  
pp. 1950038 ◽  
Author(s):  
J. V. Araujo dos Santos ◽  
A. Katunin ◽  
H. Lopes
Keyword(s):  
Wavelet Transform ◽  
Numerical Model ◽  
Natural Frequencies ◽  
Damage Identification ◽  
Wavelet Coefficient ◽  
High Sensitivity ◽  
Discrete Wavelet ◽  
Post Processing ◽  
Damage Scenarios ◽  
Spline Wavelets

This paper presents a method for the identification of damage in plates based on the post-processing with wavelets of modal rotation fields. These modal rotation fields are obtained by use of a numerical model of shearography, which includes the simulation of noise in the data generated. The discrete wavelet transform was chosen because of its high sensitivity to perturbations in the modal rotations. Distinct damage scenarios, defined by regions where the thickness of a plate is reduced, are considered in this paper. A study on the differences in the natural frequencies and the changes in modal rotation fields due to the damage is carried out. The order of the B-spline wavelets used in the post-processing of the modal rotation fields is discussed. The damage detectability in terms of its intensity, the selected mode, and the type of rotation field and wavelet coefficient is also studied. Finally, a scheme for the damage detectability enhancement, in particular for multiple damage scenarios, is proposed.

APPLYING THE ISF TECHNOLOGY TO PRODUCE THE CAR PART MODELS

2010 ◽  
Vol 13 (4) ◽  
pp. 91-98
Author(s):  
Tuan Dinh Phan ◽  
Binh Thien Nguyen ◽  
Dien Khanh Le ◽  
Phuong Hoang Pham
Keyword(s):  
Rapid Prototyping ◽  
Incremental Sheet Forming ◽  
Cad Model ◽  
Post Processing ◽  
Technological Parameters ◽  
Batch Production ◽  
Complex Products ◽  
3D Cad ◽  
Real Size ◽  
Single Batch

The paper presents an application the research results previously done by group on the influence of technological parameters to the deformation angle and finish surface quality in order to choose technology parameters for the incremental sheet forming (ISF) process to produce products for the purpose of rapid prototyping or single-batch production, including all steps from design and process 3D CAD model, calculate and select the technological parameters, setting up manufacturing and the stage of post-processing. The samples formed successfully showed high applicability of this technology to practical work, the complex products with the real size can be produced in industries: automotive, motorcycle, civil...

On the issue of environmental damage identification from oil pollution

2020 ◽  
pp. 17-21
Author(s):  
M.M. Zaderigolova ◽  
◽  
S.V. Fradkin ◽  
D.Е. Yakushev ◽  
V.A. Kalinin ◽  
...  
Keyword(s):  
Damage Identification ◽  
Oil Pollution ◽  
Environmental Damage

Deteksi Bentuk Objek Bawah Tanah Menggunakan Pengolahan Citra B-Scan pada Ground Penetrating Radar (GPR)

2017 ◽  
Vol 3 (1) ◽  
pp. 73-83
Author(s):  
Rahmayati Alindra ◽  
Heroe Wijanto ◽  
Koredianto Usman
Keyword(s):  
Signal Processing ◽  
Ground Penetrating Radar ◽  
Post Processing ◽  
Data Survey ◽  
Ground Penetrating

Ground Penetrating Radar (GPR) adalah salah satu jenis radar yang digunakan untuk menyelidiki kondisi di bawah permukaan tanah tanpa harus menggali dan merusak tanah. Sistem GPR terdiri atas pengirim (transmitter), yaitu antena yang terhubung ke generator sinyal dan bagian penerima (receiver), yaitu antena yang terhubung ke LNA dan ADC yang kemudian terhubung ke unit pengolahan data hasil survey serta display sebagai tampilan output-nya dan post  processing untuk alat bantu mendapatkan informasi mengenai suatu objek. GPR bekerja dengan cara memancarkan gelombang elektromagnetik ke dalam tanah dan menerima sinyal yang dipantulkan oleh objek-objek di bawah permukaan tanah. Sinyal yang diterima kemudian diolah pada bagian signal processing dengan tujuan untuk menghasilkan gambaran kondisi di bawah permukaan tanah yang dapat dengan mudah dibaca dan diinterpretasikan oleh user. Signal processing sendiri terdiri dari beberapa tahap yaitu A-Scan yang meliputi perbaikan sinyal dan pendektesian objek satu dimensi, B-Scan untuk pemrosesan data dua dimensi  dan C-Scan untuk pemrosesan data tiga dimensi. Metode yang digunakan pada pemrosesan B-Scan salah satunya adalah dengan  teknik pemrosesan citra. Dengan pemrosesan citra, data survey B-scan diolah untuk didapatkan informasi mengenai objek. Pada penelitian ini, diterapkan teori gradien garis pada pemrosesan citra B-scan untuk menentukan bentuk dua dimensi dari objek bawah tanah yaitu persegi, segitiga atau lingkaran. 

A Flying Gray Ball Multi-illuminant Image Dataset for Color Research

2020 ◽  
Vol 64 (5) ◽  
pp. 50411-1-50411-8
Author(s):  
Hoda Aghaei ◽  
Brian Funt
Keyword(s):  
Machine Vision ◽  
Spectral Reflectance ◽  
Color Constancy ◽  
Ground Truth ◽  
Practical Approach ◽  
Post Processing ◽  
Illumination Estimation ◽  
Processing Step ◽  
Image Dataset

Abstract For research in the field of illumination estimation and color constancy, there is a need for ground-truth measurement of the illumination color at many locations within multi-illuminant scenes. A practical approach to obtaining such ground-truth illumination data is presented here. The proposed method involves using a drone to carry a gray ball of known percent surface spectral reflectance throughout a scene while photographing it frequently during the flight using a calibrated camera. The captured images are then post-processed. In the post-processing step, machine vision techniques are used to detect the gray ball within each frame. The camera RGB of light reflected from the gray ball provides a measure of the illumination color at that location. In total, the dataset contains 30 scenes with 100 illumination measurements on average per scene. The dataset is available for download free of charge.

A Study of Different Methodologies Helpful in the Identification of Offline Handwritten Script

2018 ◽  
Vol 6 (6) ◽  
pp. 307
Author(s):  
Manish M. Kayasth ◽  
Bharat C. Patel
Keyword(s):  
Feature Extraction ◽  
Character Recognition ◽  
Recognition Rate ◽  
Recognition System ◽  
Post Processing ◽  
Classification Technique ◽  
Scanned Image ◽  
Gujarati Language ◽  
High Degree ◽  
Selection Of

The entire character recognition system is logically characterized into different sections like Scanning, Pre-processing, Classification, Processing, and Post-processing. In the targeted system, the scanned image is first passed through pre-processing modules then feature extraction, classification in order to achieve a high recognition rate. This paper describes mainly on Feature extraction and Classification technique. These are the methodologies which play an important role to identify offline handwritten characters specifically in Gujarati language. Feature extraction provides methods with the help of which characters can identify uniquely and with high degree of accuracy. Feature extraction helps to find the shape contained in the pattern. Several techniques are available for feature extraction and classification, however the selection of an appropriate technique based on its input decides the degree of accuracy of recognition. 

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