To enhance the assessment of reactor pressure vessel life under severe accident, a cooperative research program is conducted between CEA, EDF, and Framatome, parts of which are supported by the European Commission. Within the framework of this program, a model based on Lemaitre and Chaboche with predictive capability in the field of viscoplastic flow, material damage, and failure has been generalized and implemented in CASTEM 2000 finite element code. In order to validate the model in mechanical situations featuring the same basic characteristics as the severe accident scenarios, analytical experiments are conducted on the RUPTHER facility: a thin shell tube is loaded with an internal pressure and submitted to an axial thermal gradient with elevated temperatures. The specific question of the interest of the coupled damage approach in the failure prediction is addressed. Comparisons of the predictions relying on coupled and uncoupled damage-viscoplasticity models show that, at higher temperatures, failure could be predicted through uncoupled damage evaluation provided the main nonlinear effects like large displacements and updated pressure are taken into account, while at lower temperatures coupling between damage and deformation is necessary. Examples based on some RUPTHER creep test predictions are given.
The use of phased-arrays techniques has considerably contributed to extend the domain of applications and the performances of ultrasonic methods on complex configurations. Their adaptability offers a great freedom for conceiving the inspection leading to a wide range of functionalities gathering electronic commutation, applications of different delay laws and so on. This advantage allows to circumvent the difficulties encountered with more classical techniques especially when the inspection is assisted by simulation at the different stages : probe design (optimization of the number and characteristics of the elements), evaluation of the performances in terms of flaw detection (zone coverage) and characterization, driving the array (computation of adapted delay laws) and finally analyzing the results (versatile model-based imaging tools allowing in particular to locate the data in the real space). The CEA is strongly involved in the development of efficient simulation-based tools adapted to these needs. In this communication we present the recent advances done at CEA in this field and show several examples of complex NDT phased arrays applications. On these cases we show the interest and the performances of simulation-helped array design, array-driving and data analysis.
Producing reliable and robust software has become one of the most important software development concerns in recent years. Testing is a process by which software quality can be assured through the collection of information about software. While testing can improve software reliability, current tools typically are inflexible and have high overheads, making it challenging to test large software projects. In this paper, we describe a new scalable and flexible framework, called SoftTest, for testing Java programs with a novel path-based approach to coverage testing. We describe an initial implementation of the framework for branch coverage testing and demonstrate the feasibility of our approach.
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