Study on tearing tests and the determination of fracture toughness of PVC-coated fabric

In this study, detailed uniaxial in-plane tearing tests including uniaxial central, single-edge notched, and trapezoidal tearing tests of a type of polyvinylchloride (PVC)-coated polyester fiber fabric were conducted. Two types of tearing failure modes, brutal and progressive, were examined. In addition to differences in the descending sections of the stress–displacement curves and the membrane surface morphology near the crack, it was found that the uniaxial central tearing test could be replaced by the corresponding single-edge notched tearing test to minimize the usage of test materials. The configuration of the single-edge notched specimen, including the gauge length and width, was investigated to determine the conditions under which the tearing resistance of the practically nearly infinite membrane surface can be studied with finite-size specimens. To obtain the fracture toughness G _IC , which characterizes the ability of materials to prevent crack growth, a theoretical method and two test methods were introduced. After comparing the methods, the test method based on the area of the parallelogram obtained from the zigzag wave in the descending section of the load–displacement curves was proved to be superior. The value of G _IC obtained with this simple test method was relatively stable, and it could be used to evaluate the tearing resistance and calculate the tearing strength of the coated fabrics.