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Fracture Surface Topography Analysis (FRASTA) Technology for Diagnosing + Predicting Structural Failures
SRI has developed a breakthrough technology for diagnosing and predicting fatigue failure in pipelines, aircraft, bridges, power plants, and other structures using quantitative three-dimensional fractography.
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| FRASTA-generated Elevation View of a Growing Crack |
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| FRASTA-generated Plan View of a Growing Crack |
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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 structural health.
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New Research Opportunity
Recent natural gas pipeline failures have prompted interest in new forensic techniques to determine their root cause. Faced with the possibility of increased requirements to perform hydro-testing and spike testing on vintage pipes, pipeline operators need tools to understand and predict the impact of operating procedures on crack initiation, growth, and arrest.
Organizations with an interest in supporting research in these areas should contact SRI's Center of Excellence in Energy for information on a new program to develop a model to predict the impact of pressurization from hydro-testing and spike testing on crack growth.
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Advancing Fracture Science with FRASTA
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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, 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 three-dimensional 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. |
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