TY - EJOU
AU - Piao, Siyang
AU - Ouyang, Huajiang
AU - Zhang, Yahui
TI - Beam Approximation for Dynamic Analysis of Launch Vehicles Modelled as Stiffened Cylindrical Shells
T2 - Computer Modeling in Engineering \& Sciences
PY - 2020
VL - 122
IS - 2
SN - 1526-1506
AB - A beam approximation method for dynamic analysis of launch vehicles
modelled as stiffened cylindrical shells is proposed. Firstly, an initial beam model of the
stiffened cylindrical shell is established based on the cross-sectional area equivalence
principle that represents the shell skin and its longitudinal ribs as a beam with annular
cross-section, and the circumferential ribs as lumped masses at the nodes of the beam
elements. Then, a fine finite element model (FE model) of the stiffened cylindrical shell
is constructed and a modal analysis is carried out. Finally, the initial beam model is
improved through model updating against the natural frequencies and mode shapes of the
fine FE model of the shell. To facilitate the comparison between the mode shapes of the
fine FE model of the stiffened shell and the equivalent beam model, a weighted nodal
displacement coupling relationship is introduced. To prevent the design parameters used
in model updating from converging to incorrect values, a pre-model updating procedure
is added before the proper model updating. The results of two examples demonstrate that
the beam approximation method presented in this paper can build equivalent beam
models of stiffened cylindrical shells which can reflect the global longitudinal, lateral and
torsional vibration characteristics very well in terms of the natural frequencies.
KW - Finite element method
KW - model updating
KW - stiffened shell
KW - beam approximation
KW - model reduction
DO - 10.32604/cmes.2020.08789