scholarly journals Damage Identification of a Derrick Steel Structure Based on the HHT Marginal Spectrum Amplitude Curvature Difference

2017 ◽  
Vol 2017 ◽  
pp. 1-9
Author(s):  
Dongying Han ◽  
Shimin Wei ◽  
Peiming Shi ◽  
Ying Zhang ◽  
Kai Gao ◽  
...  
Keyword(s):  
Damage Identification ◽  
Steel Structure ◽  
Steel Structures ◽  
High Order ◽  
Laboratory Model ◽  
Damage Location ◽  
Marginal Spectrum ◽  
The Impact ◽  
Instantaneous Energy ◽  
Spectrum Amplitude

For the damage identification of derrick steel structures, traditional methods often require high-order vibration information of structures to identify damage accurately. However, the high-order vibration information of structures is difficult to acquire. Based on the technology of signal feature extraction, only using the low-order vibration information, taking the right front leg as an example, we analyzed the selection of HHT marginal spectrum amplitude and the calculation process of its curvature in practical application, designed the damage conditions of a derrick steel structure, used the index and intrinsic mode function (IMF) instantaneous energy curvature method to perform the damage simulation calculation and comparison, and verified the effect of identifying the damage location in a noisy environment. The results show that the index can accurately determine the location of the damage element and weak damage element and can be used to qualitatively analyze the damage degree of the element; under the impact load, the noise hardly affects the identification of the damage location. Finally, this method was applied to the ZJ70 derrick steel structure laboratory model and compared with the IMF instantaneous energy curvature method. We verified the feasibility of this method in the damage location simulation experiment.

A Novel Two-Stage Structural Damage Identification Method Based on Superposition of Modal Flexibility Curvature and Whale Optimization Algorithm

2021 ◽  
pp. 2150169
Author(s):  
Minshui Huang ◽  
Xihao Cheng ◽  
Zhigang Zhu ◽  
Jin Luo ◽  
Jianfeng Gu
Keyword(s):  
Optimization Algorithm ◽  
Damage Identification ◽  
Whale Optimization Algorithm ◽  
Two Stage ◽  
Simply Supported ◽  
Damage Location ◽  
Flexibility Matrix ◽  
Modal Flexibility ◽  
Whale Optimization ◽  
The Impact

A novel two-stage method is proposed to properly identify the location and severity of damage in plate structures. In the first stage, a superposition of modal flexibility curvature (SMFC) is adopted to locate the damage accurately, and the identification index of modal flexibility matrix is improved. The low-order modal parameters are used and a new column matrix is formed based on the modal flexibility matrix before and after the structure is damaged. The difference of modal flexibility matrix is obtained, which is used as a damage identification index. Meanwhile, based on SMFC, a method of weakening the “vicinity effect” is proposed to eliminate the impact of the surrounding elements to the damaged elements when damage identification is carried out for the plate-type structure. In the second stage, the objective function based on the flexibility matrix is constructed, and according to the damage location identified in the first stage, the actual damage severity is determined by the enhanced whale optimization algorithm (EWOA). In addition, the effects of 3% and 10% noise on damage location and severity estimation are also studied. By taking a simply supported beam and a four-side simply supported plate as examples, the results show that the method can accurately estimate the damage location and quantify the damage severity without noise. When considering noise, the increase of noise level will not affect the assessment of damage location, but the error of quantifying damage severity will increase. In addition, damage identification of a steel-concrete composite bridge (I-40 Bridge) under four damage cases is carried out, and the results show that the modified method can evaluate the damage location and quantify 5%–92% of the damage severity.

Structural Health Monitoring for Steel Structures

2013 ◽  
Vol 351-352 ◽  
pp. 1088-1091
Author(s):  
Xin Wang ◽  
Wei Bing Hu
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Damage Identification ◽  
Steel Structures ◽  
Fingerprint Analysis ◽  
Structural Health ◽  
Network Methods ◽  
Different Types ◽  
The Impact ◽  
Identification Strategy

The process of implementing a damage identification strategy for aerospace, civil and mechanical engineering infrastructure is referred to as structural health monitoring. Many different types and degrees accidents take place, especially some important collapse accidents, the significance of steel structural health monitoring has been recognized. The introduction begins with a brief research status of steel structural health monitoring in china and the world. The paper analyzes the projects and contents of steel structures monitoring from nine aspects and summarizes the diagnosis methods of steel structural damages which include power fingerprint analysis, the methods of model correction and system identification, neural network methods, genetic algorithm and wavelet analysis, it provides us theoretical guidence. In conclusion, structural health monitoring for steel structures could reduce the impact of such disasters immediately after natural hazards and man-made disasters both economically and socially, thus it is becoming increasingly important.

Effects of Snow Load on Light-Weight Steel Structures

2014 ◽  
Vol 501-504 ◽  
pp. 777-781 ◽  
Author(s):  
Fang Hui Li ◽  
Fan Meng
Keyword(s):  
Construction Industry ◽  
Rapid Development ◽  
Steel Structure ◽  
Steel Structures ◽  
Light Weight ◽  
Structural System ◽  
Snow Load ◽  
The Impact ◽  
Research Situation ◽  
Modern Building

With the rapid development of economic and construction industry, light-weight steel structural system is widely used in the modern building construction. While, the light-weight steel structures are more sensitive under the effect of snow load than the other structure systems according to the data from the large amount of accidents of steel structure failures, which indicated the necessary and urged us to focus on the impact of snow on the light-weight steel structures. This paper introduces the current research situation and analyzes the method of snow load determination on gable frames in the load code of different countries, and provides some suggestions on the snow load design of light-weight steel structures finally.

scholarly journals Desain Alat Uji Impak Jatuh Bebas Untuk Pengujian Baja Struktur

2020 ◽  
Vol 1 (2) ◽  
pp. 29-37
Author(s):  
Dailami Dailami ◽  
Samsul Bahri ◽  
Hamdani Hamdani
Keyword(s):  
Structural Steel ◽  
Impact Test ◽  
Steel Structure ◽  
Steel Structures ◽  
Free Fall ◽  
Operating Conditions ◽  
Impact Testing ◽  
Test Tool ◽  
Price Momentum ◽  
The Impact

Abstract Impact testing is a test to measure material resistance to shock loads (dynamic). Impact testing simulates the material operating conditions often encountered when the load does not always occur slowly but rather comes suddenly. The impact test equipment to be designed in this study is a free-fall impact test. This impact test tool utilizes the mass of the object and the force of gravity. This test aims to analyze the effect of free fall impact loading on steel structures dropped from 1.5m height. The steps taken in this study include testing and data collection to determine the energy absorbed, the impact price, momentum, impulse and toughness in steel structure material when given a shock load. In this free fall impact test, weight load is at (m) = 2.4 kg with an altitude distance of (h) = 1.5m. The test results showed that the maximum absorbable energy of structural steel is at (E) = 352.94 J, the maximum impact value of structural steel at (HI) = 8.82 J / mm2, the maximum momentum of structural steel at (M) 39.04 kg.m / s and the maximum implant steel structure at (I) 39.04 Ns. Mechanical behaviour is indicated by the bending of the specimen due to impact collision (striker) when testing is done. Keywords: Free-fall impact, Structure steel __________________________ Abstrak Pengujian impak merupakan suatu pengujian untuk mengukur ketahanan bahan terhadap beban kejut (dinamis). Pengujian impak mensimulasikan kondisi operasi material yang sering ditemui dimana beban tidak selamanya terjadi secara perlahan-lahan melainkan datang secara tiba-tiba. Alat uji impak yang akan dirancang dalam penelitian ini merupakan alat uji impak jatuh bebas. Alat uji impak ini memanfaatkan massa benda serta gaya gravitasi. Pengujian ini bertujuan untuk menganalisa pengaruh pembebanan impak jatuh bebas pada baja struktur yang dijatuhkan dari ke tinggian 1,5m. Langkah yang dilakukan dalam penelitian ini meliputi pengujian dan pengambilan data untuk mengetahui energi yang diserap, harga impak, momentum, implus dan ketangguhan pada material baja struktur saat diberi beban kejut. Pada pengujian impak jatuh bebas ini, mempunyai jarak dan berat beban yaitu pada beban (m) = 2,4 kg dengan jarak ketinggian (h) = 1,5m . Dari hasil pengujian yang diperoleh energi yang diserap maksimum baja struktur (E) = 352,94 J, harga impak maksimum baja struktur (HI) = 8,82 J/mm2, momentum maksimum baja struktur (M) 39,04 kg.m/s dan implus maksimum baja struktur (I) 39,04 Ns. Perilaku mekanis ditunjukkan dengan terjadinya pembengkokan pada spesimen akibat benturan Beban (striker) saat pengujian dilakukan. Kata Kunci: Impak jatuh bebas, Baja struktur __________________________

scholarly journals Application of Wavelet Transform to Damage Identification in the Steel Structure Elements

2020 ◽  
Vol 10 (22) ◽  
pp. 8198
Author(s):  
Anna Knitter-Piątkowska ◽  
Arkadiusz Dobrzycki
Keyword(s):  
Wavelet Transform ◽  
Damage Identification ◽  
Steel Structure ◽  
Metal Plate ◽  
Structural Elements ◽  
Mechanical Waves ◽  
Electroacoustic Transducer ◽  
Experimental Possibility ◽  
The Impact ◽  
The Relationship

This work concerns the concept and verification of the experimental possibility of using a wavelet transform to assess a steel structure’s condition. In the research, a developed measuring stand was used. Mechanical waves in the metal plate were excited by the impact. These waves were recorded with an electroacoustic transducer and registered in the form of electrical signals. Both the signals generated by the actuator of the plate and the signals reaching the transducer were recorded. The registered data were decomposed into wavelet coefficients. Laboratory tests have shown the possibility of applying this type of test to identify damage in steel structural elements—the relationship between the details of the wavelet transform and the type of damage was demonstrated.

scholarly journals Vibration Signal Analysis of Chimney Blasting Based on HHT

2021 ◽  
Author(s):  
Sen Huang ◽  
Linna Li ◽  
Dongwang Zhong ◽  
Li He ◽  
Jianfeng Si
Keyword(s):  
Vibration Signal ◽  
Blasting Vibration ◽  
Feature Identification ◽  
Hilbert Huang Transform ◽  
High Rise ◽  
Mode Decomposition ◽  
Marginal Spectrum ◽  
Vibration Signal Analysis ◽  
The Impact ◽  
Instantaneous Energy

In the blasting demolition processs of high-rise structures, the impact of blasting vibration to the environment and objects to be protected must be effectively controlled, so the blasting vibration signal is deeply analyzed [1]. In this paper, the blasting vibration signal of a chimney is analyzedbased on HHT. The blasting vibration signal is denoised by Empirical Mode Decomposition (EMD)-wavelet threshold, then using Hilbert-Huang Transform (HHT) [2] the measured blasting vibration waveform Hilbert spectrum, marginal spectrum and instantaneous energy graph are draw to analyze the chimney blasting vibration. The results show that the denoising effect of EMD-wavelet threshold is good for blasting vibration signal [3]. HHT method has a good feature identification ability when processing vibration signals, and can reflect the characteristics of data more comprehensively and accurately, which provides convenience for the study of vibration signal data.

Dynamic Characteristics of Base-Isolated Steel Frame under Seismic Ground Motion

2011 ◽  
Vol 255-260 ◽  
pp. 2341-2344
Author(s):  
Mohammad Saeed Masoomi ◽  
Siti Aminah Osman ◽  
Ali Jahanshahi
Keyword(s):  
Ground Motion ◽  
Base Isolation ◽  
Time History ◽  
Steel Structure ◽  
Steel Structures ◽  
Steel Frame ◽  
Nonlinear Time History Analysis ◽  
Seismic Load ◽  
Vector Method ◽  
Seismic Ground Motion

This paper presents the performance of base-isolated steel structures under the seismic load. The main goals of this study are to evaluate the effectiveness of base isolation systems for steel structures against earthquake loads; to verify the modal analysis of steel frame compared with the hand calculation results; and development of a simulating method for base-isolated structure’s responses. Two models were considered in this study, one a steel structure with base-isolated and the other without base-isolated system. The nonlinear time-history analysis of both structures under El Centro 1940 seismic ground motion was used based on finite element method through SAP2000. The mentioned frames were analyzed by Eigenvalue method for linear analysis and Ritz-vector method for nonlinear analysis. Simulation results were presented as time-acceleration graphs for each story, period and frequency of both structures for the first three modes.

scholarly journals Experimental study on fatigue performance of Q420qD high-performance steel cross joint in complex environment

2021 ◽  
Author(s):  
Haigen Cheng ◽  
Cong Hu ◽  
Yong Jiang
Keyword(s):  
Fatigue Life ◽  
High Performance ◽  
Steel Structure ◽  
Steel Structures ◽  
Fatigue Tests ◽  
Fatigue Performance ◽  
Corrosive Media ◽  
Joint Connection ◽  
High Performance Steel ◽  
The Cross

AbstractThe steel structure under the action of alternating load for a long time is prone to fatigue failure and affects the safety of the engineering structure. For steel structures in complex environments such as corrosive media and fires, the remaining fatigue life is more difficult to predict theoretically. To this end, the article carried out fatigue tests on Q420qD high-performance steel cross joints under three different working conditions, established a 95% survival rate $$S{ - }N$$ S - N curves, and analyzed the effects of corrosive media and high fire temperatures on its fatigue performance. And refer to the current specifications to evaluate its fatigue performance. The results show that the fatigue performance of the cross joint connection is reduced under the influence of corrosive medium, and the fatigue performance of the cross joint connection is improved under the high temperature of fire. When the number of cycles is more than 200,000 times, the design curves of EN code, GBJ code, and GB code can better predict the fatigue life of cross joints without treatment, only corrosion treatment, and corrosion and fire treatment, and all have sufficient safety reserve.

scholarly journals A New Approach for Cylindrical Steel Structure Deformation Monitoring by Dense Point Clouds

2021 ◽  
Vol 13 (12) ◽  
pp. 2263
Author(s):  
Dongfeng Jia ◽  
Weiping Zhang ◽  
Yuhao Wang ◽  
Yanping Liu
Keyword(s):  
Steel Structure ◽  
Steel Structures ◽  
Point Clouds ◽  
Deformation Monitoring ◽  
Deformation Analysis ◽  
Relative Deformation ◽  
Structure Deformation ◽  
Single Time ◽  
Cylindrical Steel ◽  
Cylinder Fitting

As fundamental load-bearing parts, the cylindrical steel structures of transmission towers relate to the stability of the main structures in terms of topological relation and performance. Therefore, the periodic monitoring of a cylindrical steel structure is necessary to maintain the safety and stability of existing structures in energy transmission. Most studies on deformation analysis are still focused on the process of identifying discrepancies in the state of a structure by observing it at different times, yet relative deformation analysis based on the data acquired in single time has not been investigated effectively. In this study, the piecewise cylinder fitting method is presented to fit the point clouds collected at a single time to compute the relative inclination of a cylindrical steel structure. The standard deviation is adopted as a measure to evaluate the degree of structure deformation. Meanwhile, the inclination rate of each section is compared with the conventional method on the basis of the piecewise cylinder fitting parameters. The validity and accuracy of the algorithm are verified by real transmission tower point cloud data. Experimental results show that the piecewise cylinder fitting algorithm proposed in this research can meet the accuracy requirements of cylindrical steel structure deformation analysis and has high application value in the field of structure deformation monitoring.

scholarly journals Wavelet Energy Accumulation Method Applied on the Rio Papaloapan Bridge for Damage Identification

Mathematics ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 422
Author(s):  
Jose M. Machorro-Lopez ◽  
Juan P. Amezquita-Sanchez ◽  
Martin Valtierra-Rodriguez ◽  
Francisco J. Carrion-Viramontes ◽  
Juan A. Quintana-Rodriguez ◽  
...  
Keyword(s):  
Bridge Deck ◽  
Damage Identification ◽  
Area Under The Curve ◽  
Economic Losses ◽  
Civil Structures ◽  
Vibration Signals ◽  
Energy Accumulation ◽  
Damage Location ◽  
Wavelet Energy ◽  
Accumulation Method

Large civil structures such as bridges must be permanently monitored to ensure integrity and avoid collapses due to damage resulting in devastating human fatalities and economic losses. In this article, a wavelet-based method called the Wavelet Energy Accumulation Method (WEAM) is developed in order to detect, locate and quantify damage in vehicular bridges. The WEAM consists of measuring the vibration signals on different points along the bridge while a vehicle crosses it, then those signals and the corresponding ones of the healthy bridge are subtracted and the Continuous Wavelet Transform (CWT) is applied on both, the healthy and the subtracted signals, to obtain the corresponding diagrams, which provide a clue about where the damage is located; then, the border effects must be eliminated. Finally, the Wavelet Energy (WE) is obtained by calculating the area under the curve along the selected range of scale for each point of the bridge deck. The energy of a healthy bridge is low and flat, whereas for a damaged bridge there is a WE accumulation at the damage location. The Rio Papaloapan Bridge (RPB) is considered for this research and the results obtained numerically and experimentally are very promissory to apply this method and avoid accidents.

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