Crack propagation prediction of CFRP retrofitted steel plates with different degrees of damage using BEM
- Authors: Yu, Qian Qian , Zhao, Xiao , Chen, Tao , Gu, Xianglin , Xiao, Zhigang
- Date: 2014
- Type: Text , Journal article
- Relation: Thin-Walled Structures Vol. 82, no. (2014), p. 145-158
- Full Text: false
- Reviewed:
- Description: Although carbon fibre reinforced polymer (CFRP) materials have proven effective in strengthening steel structures especially when used to improve fatigue behaviour, further study is required to investigate their effectiveness when applied at different stages of crack propagation in steel elements. This paper presents a numerical study on CFRP retrofitted steel plates with different degrees of damage using the boundary element method (BEM). The numerical results compared well with the experimental data, which demonstrated that the BEM is reliable for crack propagation analysis of CFRP laminate retrofitted steel plates. Finally, a parametric analysis was conducted to investigate the influence of bond length, bond width, CFRP stiffness and adhesive shear modulus on stress intensity factor (SIF) values. © 2014 Elsevier Ltd.
Evaluation of stress intensity factor for CFRP bonded steel plates
- Authors: Yu, Qian Qian , Zhao, Xiao , Xiao, Zhigang , Chen, Tao , Gu, Xianglin
- Date: 2014
- Type: Text , Journal article
- Relation: Advances in Structural Engineering Vol. 17, no. 12 (2014), p. 1729-1746
- Full Text: false
- Reviewed:
- Description: Recent studies on the application of carbon fibre reinforced polymer (CFRP) materials to defected steel structures have demonstrated the potential for significant reduction of stress intensity factor (SIF) values at crack tips leading to extended fatigue lives. However, most of the previous research relied on experimental and numerical methods, which were either expensive or time-consuming. In this paper, the SIF values at crack tips of steel plates strengthened with bonded composite materials were evaluated using linear elastic fracture mechanics. The analysis was based on the classical solution of SIF values of plain steel plates, considering load share effect and geometry correction factor change resulted from the overlay patch. The effect of different parameters were demonstrated and compared with experimental results, including initial damage degrees of specimens, geometric and mechanical properties of retrofitting materials and bond locations. Good agreement with the experimental data indicated that this approach could conservatively predict the SIF values with reasonable accuracy. A parametric study on variables including the CFRP modulus, the bond width and bond length was conducted based on this method to further investigate their effect on the SIF values.
Fatigue behaviour of CFRP strengthened steel plates with different degrees of damage
- Authors: Yu, Qian Qian , Chen, Tao , Gu, Xianglin , Zhao, Xiao , Xiao, Zhigang
- Date: 2013
- Type: Text , Journal article
- Relation: Thin-Walled Structures Vol. 69, no. (2013), p. 10-17
- Full Text: false
- Reviewed:
- Description: An experimental and analytical study was conducted to further investigate the effectiveness of the carbon fibre reinforced polymer (CFRP) plates in extending fatigue life of steel structures. Different lengths of artificial cracks were introduced to represent different degrees of fatigue damage. The experimental results demonstrated that the CFRP patches could effectively slow down the crack growth and prolong the fatigue life. A theoretical model was developed to predict the fatigue life of tested specimens. Thereafter, a parametric study was carried out to investigate the fatigue behaviour of steel plates with a wider range of damage degrees. This study extends the understanding of CFRP repair at different stages of crack propagation and provides some useful suggestions for the strengthening method.
A boundary element analysis of non-load-carrying cruciform welded joints strengthened with FRP materials
- Authors: Chen, Tao , Zhao, Xiao , Gu, Xianglin , Xiao, Zhigang
- Date: 2012
- Type: Text , Conference paper
- Relation: International Conferences on Advances in Steel Structures 2012 p. 1405 - 1412
- Full Text: false
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Formula for SIF of cracked steel plates strengthened with CFRP plate
- Authors: Yu, Qian Qian , Zhao, Xiao , Chen, Tao , Xiao, Zhigang , Gu, Xianglin
- Date: 2012
- Type: Text , Conference paper
- Relation: 22nd Australasian Conference on the Mechanics of Structures and Materials, ACMSM 2012 p. 537-540
- Full Text: false
- Reviewed:
- Description: Fatigue loading will lead to crack initiation and crack growth in steel structures where stress concentration exists. Fatigue life of aged steel members can be extended significantly with carbon fiber reinforced polymer (CFRP) repair. Stress intensity factor (SIF) is a key parameter to calculate the fatigue life and analyze the progress of crack development. There is a lack of knowledge of SIF for cracked steel plate with different degrees of damage strengthened with CFRP. This paper aims to fill this knowledge gap. The SIF formula is developed based on the classical SIF solution and James-Anderson method by considering two correction factors, representing the effect of load share effect in composite system and the effect of initial damage degree, respectively. It is demonstrated that the SIF formula proposed in the paper is applicable to SIF estimation of strengthened center cracked steel plate with different degrees of damage.