Experimental investigation of failure modes and ultimate strength of GFRP structure members under longitudinal compression

Due to the higher strength and lightweight of glass fiber reinforced polymer (GFRP), its application in ship structures is becoming increasingly prevalent. However, the mechanical properties of GFRP are affected by many factors, such as fabrication techniques and structural connection designs. The true safety margin of the GFRP structure is necessary to investigate in engineering applications. This study carries out experimental investigations of the ultimate strength and failure modes for three typical GFRP structural members, including stringer, longitudinal stiffener and hard corner, which constitute the cross section of the hull girder. The three kinds of structure members exhibit different failure modes: the stringer exhibits yielding failure, the longitudinal stiffener exhibits buckling and interlayer delamination, and the hard corner presents buckling and debonding. Finally, the finite element analysis is validated by the experimental results to assess the ultimate strength of the GFRP structure. The foam core effectively enhances the structural strength of the stringer and longitudinal stiffener, while the hard corners require a change in the connection method to increase the connection strength. The conclusions can be used as guidance for safety analysis of GFRP structures in ships. •Investigation of failure modes and ultimate strength of composite structure under longitudinal compression.•Experimental study on three kinds of GFRP structure members: stringer, longitudinal stiffener, and hard corner.•Experiment models present different failure modes, including yielding, buckling, and delamination at the interlayer.•Simulations validate finite element analysis for predicting composite structures' mechanical behavior and strength.•The foam core enhances the strength, while the hard corner requires better connection methods to increase the strength.