Jrq. Franco et al., A-POSTERIORI ERROR ESTIMATOR AND ADAPTIVE PROCEDURES FOR COMPUTATION OF SHAKEDOWN AND LIMIT LOADS ON PRESSURE-VESSELS, Computer methods in applied mechanics and engineering, 150(1-4), 1997, pp. 155-171
Adaptive finite element procedures are presented for the computation o
f upper bounds estimates of limit and shakedown loads for pressure ves
sels. The method consists of an h-type adaptive mesh refinement strate
gy based upon an a-posteriori error estimator measured by the energy n
orm. The problem is formulated in a kinematic approach using Koiter's
shakedown theorem. A constitutive model, for elastic-perfectly plastic
materials, relates the plastic strains increments and curvatures to p
lastic multipliers through the flow law associated with a shelf piecew
ise-linear yield surface (hexagonal prism). A consistent relationship
between nodal displacements and nodal plastic multipliers is enforced
by minimizing the strain residual between the total strain and the pla
stic strain increments, which is measured with respect to the energy n
orm. Discretization of the shell into finite elements allows the reduc
tion of the problem to a minimization problem which is solved by linea
r programming.