Papers by Keyword: Damage Index

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Authors: Hua Zhang, Y.C. Xiao, Ming Li, G.Q. Liu, Jie Zhang
Abstract: L shaped braided composites under fatigue load was researched, using piezoelectric sensors and active Lamb wave monitoring technology. HHT transform based signal envelope obtaining method and the damage index method based on signal energy change were used to monitor the damage extending of the braided composites.
Authors: Yang Yang, Meng Yang Zhang, Li Xiao, Wen Zhong Qu
Abstract: Existing non-destructive test methods are usually ineffective in detection of surface breaking cracks with large depths in concrete structure. This paper introduces a method suitable for detection of deep cracks based on surface wave time reversal theory. A numerical simulation based on the finite element model is performed to investigate surface cracks detection. A damage index was defined based on the correlation coefficient between the actuated and the reconstructed wave signals. The results demonstrated that the presence of crack had a significant influence on the propagation characteristics of surface waves along concrete. Cracks in different sizes were introduced and correlated with the damage index. Enlarging the crack depth resulted in an increase in the distortion of reconstructed signals, and a higher damage index was obtained. The results illustrated the effectiveness of the surface wave time-reversal process in identifying cracks in concrete structures.
Authors: Georgios S. Kamaris, Konstantinos A. Skalomenos, George D. Hatzigeorgiou, Dimitri E. Beskos
Abstract: An empirical methodology to evaluate damage by the use of two damage indicators for 2D steel/concrete composite structures is proposed. This methodology has been established with aid of the results of an extensive parametric study regarding the non-linear behaviour of 48 steel/concrete composite frames subjected to 100 far-fault records. A large number of inelastic dynamic analyses are conducted by increasing the earthquake motions to lead the frames to several levels of non-linear response. The results of the analyses show that the characteristics of the structure and the ground motions affect damage of the structures. The results are post-processed by the use of statistical methods to generate expressions, which show the effect of the abovementioned parameters and give an evaluation of the damage indicators utilised here. In particular, given the characteristics of the frames and the record, someone can compute the maximum damage found in beams and columns. Finally, one example serves to show the use of the developed formulae and demonstrates their validity.
Authors: Ke Jia Yang, Zi Ling Xie, Wei Li
Abstract: The damage evolution equation of RPC is established based on 2-parameter Weibull distribution. The constitutive relation of RPC is then calculated based on the damage evolution equation. The constitutive model of RPC is optimized by comparing experimental constitutive curve to models corresponding to different threshold strain. Based on the definition of damage index in ABAQUS, the damaged evolution equation in ABAQUS is recalculated based on the optimized constitutive relation. the concrete damaged plasticity model in ABAQUS is obtained using the aforementioned method. And the concrete damaged plasticity model is applied to three compression member and three simply supported beams with different reinforcements. The calculated stress-strain curve and deformation of three compression member and three beams is in accordance with the deformation characteristics of experiments, which verified the effectiveness of the proposed concrete damaged plasticity model of RPC.
Authors: Yu Ying Wang, Wen Xiu Sun
Abstract: Structure damage identification is a hot research area internationally in recent years. Two damage identification methods based on sensitivity analysis are concluded. A three-tier steel frame structure model is established through utilizing ANSYS10.0, the software of finite element analysis. Through modal analysis of finite element, the frequency and formation before and after damage are obtained. The position of damage of the model is fixed by applying two damage indexes. It is indicated from the results that these two methods are effective for damage identification of the space structure of steel frame.
Authors: Jian Yi Zhang, Jing Shan Bo, Guo Dong Xu, Jing Yi Huang
Abstract: With the author and others scientific investigation on China Wenchuan Ms8.0 earthquake, China Yushu Ms7.1 earthquake and "China's active fault surveying and earthquake hazard evaluation project" relevant data results and the world requirements about project setback of active faults, etc., this paper concluded that: (1) width of Surface-Fault-Rupture is about 40m by statistics, or from the main surface rupture trace about 20m; (2) width of Surface-Fault-Rupture S and the fault vertical offset V, statistical diagrams and formulas S=8.72+9.01V; (3) Setback of the main surface trace D and buildings from damage index I, statistical diagrams and formulas I=0.7969-0.00231D; (4) based on the first three results and by the actual statistics of accuracy, we get three active fault location accuracy level of the standard i, ii, iii, respectively, the error is ± 5m, ± 25m, ± 60m, also, can give this level of standards of Surface-Fault-Rupture width to the actual engineering applications.
Authors: Heung Soo Kim, Jae Hwan Kim, Seung Bok Choi
Abstract: A modal strain based damage index is proposed to investigate the damage effects of discrete delaminations in a laminated composite structure. The Fermi-Dirac distribution function is incorporated with an improved layerwise laminate theory to model smooth transition of the displacement and the strain fields at the delaminated interfaces. Modal analysis is conducted to investigate dynamic effects of delamination in a laminated structure and to obtain modal strains. The damage index is calculated based on fundamental modal strains of laminated structures. The damage effects of laminated structures are investigated using arbitrary size, number, location and boundary conditions of discrete delaminations.
Authors: Dong Hyeon Shin, Jin Young Park, Hyung Joon Kim
Abstract: Existing non-seismically detailed low-rise RC buildings have higher seismic risks that are dependent on their seismic capacities and demand of building sites. Seismic risk analysis can be performed considering probabilistic characteristic of the structural damage. Structural damage is more accurately quantified by the damage indices than by a single engineering parameter. This study carries out comparative seismic risk analysis of a prototype building with and without metallic energy dissipating devices. Based on the probability distribution of damage index, it is demonstrated that the application of well-designed MEDDs to low-rise RC building can reduce its potential seismic risk.
Authors: Kamran Faraji, Mahmoud Miri
Abstract: For vulnerability assessment of structures, different damage indexes have been established by researchers that estimate the structural damage level. In these indexes different parameters have been used for calculating structural damage level. In this paper, damage indexes based on deformation, energy and cycle hysteretic behavior are investigated in order to find a correlation between their numerical values. The selected damage indexes are calculated and compared by applying them in nonlinear time history analysis of low and intermediate rise knee braced steel frames subjected to a set of seven earthquake accelerograms. Correlations between various indexes have been presented graphically and approximate conversion formulas are also provided.
Authors: Wei Huang, Jiang Qian, Bin Bin Zhuang, Qiu Shi Fu
Abstract: This paper presents the results of a numerical investigation aimed at evaluation of damage accumulation in structures under different seismic sequences. For this purpose, a multi-story RC frame model representing the typical buildings was built and subjected to four sets of different repeating seismic sequences with different magnitude. The results indicate that the aftershock sequences will increase the damage accumulation in structures, and the damage index based on the Park and Ang model can qualitatively and quantitatively ascertain the damage state of the structure instead of the single index based on the lateral drift demands. Additionally, different sequences with the identical energy input will cause the same damage state in structures.
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