Monday  |  Salon 10  |  10:20 AM–10:40 AM

#15463, A Novel Inverse Method for Obtaining Hoop Direction Mechanical Properties from Non-Standard Tensile Tests

Several experimental methods have been developed with the intent to determine the plastic response of irradiated cladding in the hoop direction. However, all method variations come with some disadvantages. One of the more commonly used methods is the ring tension test (RTT). While it uses relatively little material and shares similarities with traditional tensile testing, it can cause non-uniform loading of the gauge section. This results in unwanted strain concentrations and premature yielding, which means that accurate plasticity parameters cannot be obtained from the experimental load-displacement curve in the same way as a traditional tensile test. However, a novel inverse method has been developed to extract the plasticity behavior from the non-standard curve using finite element analysis. This approach consists of generating a finite element model of the test sample and experimental setup with an initial guess of plasticity behavior. The modeled load-displacement curve is compared to the experimental data, then the model is updated with new plasticity parameters and the analysis is repeated. This iterative process is continued using an optimization routine until the model converges to the experimental data. This novel approach is tailored to specifically address convergence challenges inherent to the RTT method, accommodating the plastic behavior of a range of potential materials, while also providing robustness against the noise of experimental data. When paired with RTT experiments, even in challenging environments such as high temperatures or irradiated materials, this inverse method approach enables the extraction of mechanical properties with a level of accuracy unattainable through conventional data processing techniques.

Robert Hansen   Idaho National Laboratory
David Kamerman   Idaho National Laboratory
Fabiola Cappia   Idaho National Laboratory