Notched Three‐Point Bend Testing of GFRP Woven Laminates at Cryogenic Temperatures and Analysis of Fracture and Damage Properties

The cryogenic damage and fracture properties of GFRP (glass fiber reinforced polymer) woven laminates has been investigated theoretically and experimentally. Three‐point bend tests were carried out with SENB (single‐edge‐notched bend) specimens at room temperature, liquid nitrogen temperature and liquid helium temperature. SENB specimens with different widths and thicknesses were prepared and tested. The results of SENB specimens were compared with those of CT (compact tension) specimens. A finite element analysis was also conducted to predict the response of the damaged SENB specimen. Effective elastic moduli were determined under the assumption of uniform strain inside the representative volume element. Hoffman failure criterion was selected as the criterion for fiber‐dominated failure, and matrix microcracking was detected by the maximum strain criterion. The virtual crack extension method was adopted to calculate strain energy release rate which leads to determination of stress intensity factor. In order to verify the model, correlations between experimental and analytical results were made, in terms of the load‐displacement response and the extent of damage growth. Reasonable agreements were found between the calculations and the experimental data.