Fatigue experiments on CFRP repaired welded thin-walled RHSTO-RHS cross-beam connection
- Authors: Xiao, Zhigang , Zhao, Xiao , Mashiri, Fidelis
- Date: 2008
- Type: Text , Conference paper
- Relation: Proceedings of the Tenth International Symposium on Structural Engineering for Young Experts (ISSEYE-10) p. 971-978
- Full Text: false
- Reviewed:
- Description: Cracked thin-walled rectangular hollow section (RHS)-to-RHS cross-beam connections are repaired with carbon fibre reinforced polymer (CFRP) composites and constant amplitude fatigue experiments are conducted on them. A pilot test is first conducted on a square hollow section (SHS)-to-SHS T-connection to explore an effective method of applying CFRP. Due to the “peel off” effect at the corner region of the SHS-to-SHS specimen, early debonding appears in the pilot test which only results in a small increase in fatigue life. Circumferential or transverse restraining CFRP patches are added in the RHS-to-RHS cross-beam specimens which prevent early debonding successfully and lead to significant increase in fatigue life.
Modified stress intensity factor equations for semi-elliptical surface cracks in finite thickness and width plates
- Authors: Peng, Yang , Tong, Lewei , Zhao, Xiao , Xiao, Zhigang
- Date: 2011
- Type: Text , Conference paper
- Relation: The Twelfth East Asia-Pacific Conference on Structural Engineering and Construction p. 2601-2608
- Full Text: false
- Reviewed:
- Description: Weld defects and severe variation of shape near the welds cause high stress concentration at weld toes or weld roots. This high stress concentration reduces fatigue lives of welded structures. A stress intensity factor (SIF) which includes this effect increases the accuracy of fatigue lives prediction. A magnification factor is commonly used to multiply the SIF of semi-elliptical surface cracks to account for the stress concentration effect in welded connections. Yamada and Hirt model is one of these methods. Comparison between Yamada & Hirt SIF equations and Newman & Raju SIF equations are applied to SIF of semi-elliptical surface cracks. The results suggest that Yamada & Hirt SIF equations are valid when the crack aspect ratio is less than 0.6. New empirical SIF equations are developed based on Yamada & Hirt SIF equations. The newly derived SIF equations are verified by comparing with experimental data.