Small Punch Test : EPRI-CEA Finite Element Simulation Benchmark and Inverse Method for the Estimation of Elastic Plastic Behavior

Abstract

Prolonging the service life of nuclear power plants and more stringent safety requirements are increasing the need for miniature mechanical tests such as the Small Punch Test (SPT). This test was initially developed in the early 1980s at MIT and further developments with more extensive use were achieved by EPRI with a continuous program between 1990 and 1999. The present investigation is first based on a finite element simulation benchmark between EPRI and CEA. This provided a reciprocal validation of the numerical simulation of this test for an A533 B steel at room temperature. The loading mode progressively evolves from bending towards biaxial membrane loading of the specimen. Strain energy density was also computed as the failure criterion and the maximum value observed at experimental crack initiation is about 116 MJ/m3. A parametric finite element study was undertaken in order to evaluate the influence of factors such as specimen thickness, friction, yield strength, strain hardening coefficient, etc. Starting from this parametric study, an automatic routine was built which estimates the elastic-plastic Ramberg-Osgood stress strain relation. The need for standardization of this test will be underlined.

Predicting the J integral fracture toughness of Al 6061 using the small punch test

“…More recently, these numerical methods have been improved by the incorporation of continuum damage models into FE analyses.16 16–19 Parameters for models, such as the Gurson, Tvergaard and Needleman 17,18 can then be estimated from the experimental load–displacement curve to provide a constitutive model of material behaviour. This has been achieved either by adjusting and matching parameters directly in an FE model or by using a neural network, trained by a suitably sized set of training data from FE simulations.…”

Characterisation of semi-solid material mechanical behaviour by indentation test

“…The tool/material interface behaviour is known to be a first-order parameter for processing and is unfortunately difficult to be characterised and modelled by the traditional tests. For these reasons, many authors have recently applied mixed numerical-experimental methods to determine the material and friction parameters [2][3][4][5][6][7][8][9]. In this paper, we propose to use also a mixed numerical-experimental method based on the indentation test [10][11][12] to study the rheology of semi-solid materials used in thixoforming.…”

Fracture of Zircaloy-4 cladding tubes with or without hydride blisters in uniaxial to plane strain conditions with standard and optimized expansion due to compression tests

“…Therefore, displacement-controlled mechanical tests should be preferred to characterize the cladding fracture in the PCMI phase. Punch tests techniques [11,12] are suitable to provide information for various stress state conditions. However, these tests can only be performed on sheets, which are generally not fully representative of tubular sample in terms of mechanical behaviour and fracture.…”