MODELLING THE DELAMINATION FAILURE ALONG THE CFRP-CFST BEAM INTERACTION SURFACE USING DIFFERENT FINITE ELEMENT TECHNIQUES

Abstract

Nonlinear finite element (FE) models are prepared to investigate the behaviour of concrete-filled steel tube (CFST) beams strengthened by carbon fibre reinforced polymer (CFRP) sheets. The beams are strengthened from the bottom side only by varied sheet lengths (full and partial beam lengths) and then subjected to ultimate flexural loads. Three surface interaction techniques are used to implement the bonding behaviour between the steel tube and the CFRP sheet, namely, full tie interaction (TI), cohesive element (CE) and cohesive behaviour (CB) techniques using ABAQUS software. Results of the comparison between the FE analysis and existing experimental study confirm that the FE models with the TI technique could be applicable for beams strengthened by CFRP sheets with a full wrapping length; the technique could not accurately implement the CFRP delamination failure, which occurred for beams with a partial wrapping length. Meanwhile, the FE models with the CE and CB techniques are applicable in the implementation of both CFRP failures (rapture and delamination) for both full and partial wrapping lengths, respectively. Where, the ultimate loads' ratios achieved by the FE models using TI, CE and CB techniques about 1.122, 1.047 and 1.045, respectively, comparing to the results of existing experimental tests.

Keywords

• ABAQUS
• CFST Beam
• delamination
• CFRP sheets
• Finite Element