Computational work Sample Clauses

Computational work. The goal is to provide an efficient and robust method for progressive crack propagation that allows the analyst, in only a few steps, to predict the risk of SCC for nuclear components under realistic loadings. This work will be based on the extension of a revolutionary finite element method based on multicomplex mathematics. The Complex Finite Element Method, denoted as ZFEM, was developed at UTSA under the supervision of ▇▇. ▇▇▇▇▇▇▇▇▇. ZFEM has the capability of computing arbitrary-order derivatives of the output fields of the model with respect to input parameters, including shape, material parameters and loading [26-28]. This capability was used to compute the energy release rate (or its equivalent partner-the stress intensity factor, K) in arbitrarily shaped cracked bodies. It was shown that ZFEM has the same accuracy as the J- integral when computing the energy release rate for 2D and 3D linear elastic models [29]. However, this method is simpler in concept and implementation. Recently, a ZFEM based progressive crack growth algorithm for 2D elastic materials was developed at UTSA. An appealing characteristic of this method is that large curvilinear crack progressions can be made before remeshing for a subsequent step. For SCC, the presence of the corrosive environment generates spatial and time dependent conditions at the crack tip. Plastic strain at the crack tip causes the passive film to fracture, thereby exposing fresh metal to the environment. This zone corrodes to produce an increment of crack growth. However, after a brief period, a passive film is formed again and crack growth is arrested. After accumulated plastic strain, the film fractures again and the process repeats itself [30, 31]. Hence, an accurate estimate of the plastic strain zone surrounding the crack tip is essential for accurate lifetime predictions. ZFEM can provide an accurate evaluation of the stress intensity factors for arbitrary material models, e.g. bilinear isotropic hardening, kinematic hardening, ▇▇▇▇▇▇▇ Cook plasticity model, etc. Moreover, the cyclic film rupture phenomenon can be captured in ZFEM progressive crack growth algorithm by defining a user subroutine that controls film rupture. Probability Risk Assessment (PRA) based on the Monte Carlo approach allows analysts to quantify the risk of an unwanted event, such as the rupture of a cylinder carrying reactor liquid [32]. A coupled finite element-▇▇▇▇▇-▇▇▇▇▇ simulation involves a large number of computational runs...