SRI's Fracture Surface Topography Analysis (FRASTA) technology analyzes fracture surfaces to determine how and why a structural failure occurred. In fact, the failure event can often be replayed from start to finish. Furthermore, FRASTA provides mechanistic and microstructural information that is not obtainable from conventional fracture surface analyses and can be used to predict the lifetime of structures and set inspection intervals for replacement structures.
The technology has particular value to those responsible for the integrity of aging structures. Application of FRASTA to degrading pipelines, aircraft, bridges, power plants and the like is expected to lead to better tools for managing and extending the life of a structure and new procedures for monitoring its health.
How FRASTA works
The lifetime of an aging structure is determined by a crack that initiates and grows over a long period of time.
Crack initiation and growth is accompanied by deformation occurring at the crack front.
Deformation produces roughness features on the fracture surfaces.
FRASTA quantifies and analyzes the topographies of the opposing fracture surfaces to determine deformation evolution at the microstructural level.
These data enable the growth history of the crack to be reconstructed from initiation to final failure.
The SRI-developed FRASTAscope is a commercially marketed confocal optics instrument that produces topographic maps of fracture surfaces. FRASTA software manipulates the conjugate topographs, displays images of fracture surface evolution, and plots the crack growth history. Correlation with the operational history of the structure (e.g., pipe pressurization history, hard aircraft landings, and power plant start-ups and shut-downs) provides data useful for predicting lifetime and setting inspection protocols.
SRI continues to extend 3D fracture surface analysis and develop faster, more efficient, and higher-resolution methods to quantify and interpret fracture surface topography. Fourier, wavelet, and discrete cosine transformation techniques are being applied to analyze fractographic data and extract additional information from fracture surfaces. Key goals include deducing load conditions responsible for failures and quantifying the crack nucleation process.