Abstract
Spiral Notch Torsion Test (SNTT) was developed recently to measure the intrinsic fracture toughness (KIC) of structural materials. The SNTT system operates by applying pure torsion to uniform cylindrical specimens with a notch line that spirals around the specimen at a 45 pitch. The KIC values and the associated energy release rate are obtained with the aid of a three-dimensional finite-element evaluation. The SNTT method is uniquely suitable for testing a wide variety of structural materials, including others such as ceramics, graphite, concrete, polymeric composites, and for bi-material interface fracture toughness evaluation. The SNTT test results for these structural materials and polymeric composite are demonstrated in this paper. These results demonstrated that SNTT has great potential in structural materials and polymeric composites testing, which can provide useful information for design and fabrication of structural components.