Finite-element Analysis of Composite Pressure Vessels with Progressive Degradation

  • Dr Nagesh Indian Institute of Technology Delhi, New Delhi
Keywords: Finite-element analysis, composite pressure vessel, progressive degradation, degradation model, failure analysis


A degradation model incorporated into the finite-element analysis of the pressure vessel,
based on a progressive failure criterion, has been discussed. A stiffness reduction scheme for
the failed laminas has been implemented using package ANSYS along with a reduction in the
strength of the composite (on its undegraded strength after a substantial degradation of its
constituents). The degradation model used for analysis is sensitive to the mesh and the load
step size. Computational efficiency (CPU time) of the finite-element model is very important
in the degradation study, and accordingly, equilibrium is not re-established in the nonlinear
solution procedure implemented in ANSYS (single-frame restart analysis). This is offset using
a small load step size for the degradation studies of the pressure vessel.
The model is qualified by a comparison with deformation measurements obtained from
hydrostatic tests. The experimental deformations have an excellent match with the degraded
model in comparison to the undegraded model. The redistribution of stresses in the composite
constituents as a result of degradation, has been demonstrated. The burst in the pressure vessel
is indicated by unusually large displacement and infeasible stress profile in consequence to a
substantial degradation in the fibre material of the composite.
How to Cite
Nagesh, D. (2003). Finite-element Analysis of Composite Pressure Vessels with Progressive Degradation. Defence Science Journal, 53(1), 75-86.
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