Hung Nguyen-Dang

Kinematical shakedown analysis with temperature‐dependent yield stress

SUMMARY This paper describes a direct shakedown analysis of structures subjected to variable thermal and mechanical loading. The classical kinematical shakedown theorem is modied to be implemented with any displacementbased nite elements. The plastic incompressibility condition is imposed by the penalty function method. The shakedown limit is found via a non-linear mathematical programming procedure. Two numerical shakedown methods are developed and implemented to provide alternative numerical means. The temperature-dependent material model is included in theoretical and numerical calculation in a simple way. Its eect on shakedown limit is investigated. The numerical examination for some pressure vessel structures subjected to thermal and mechanical loading shows a satisfying precision and eciency of the methods presented. Copyright ? 2001 John Wiley & Sons, Ltd.

SMOOTHED FINITE ELEMENT METHOD FOR TWO-DIMENSIONAL ELASTO-PLASTICITY

This communication shows how the smoothed finite element method (SFEM) very recently proposed by G.R. Liu [14] can be extended to elasto-plasticity. The SFEM results are in excellent agreement with the finite element (FEM) and analytical results. For the examples treated, the method is quite insensitive to mesh distortion and volumetric locking. Moreover, the SFEM yields more compliant load-displacement curves compared to the standard, displacement based FE method, as expected from the theoretical developments recently published in [4], [3] and [6].

Stress intensity factors and crack extension in a cracked pressurised cylinder

Abstract This paper considers the plane elastic problem corresponding to single or multiple radial cracks emanating from the internal boundary of a circular ring, under uniform external tension and internal pressure. The stress intensity factors are calculated by using the dual boundary element method with the J-integral technique. Accurate data are found for varying crack depths over a representative range of wall ratios for fracture mechanics applications to pressurised circular cylinders. The interaction of multiple cracks and crack extension are investigated in the case of an internal pressure loading condition. The analysis shows that, for a multi-cracked pressurised cylinder, it is sufficient to calculate the stress intensity of the main crack in isolation for the purposes of safety assessment.