Shell18 – Large Axial Displacements!!!

Example Description

This example uses a three-hinged arch to test static nonlinear analysis with large axial displacements in this model. A concentrated vertical downward load, P, is applied to the center joint of the three-hinge arch. The load P is increased until the vertical downward deflection at the center joint reaches 1 foot. The resulting vertical support reaction at joint 1 is compared with independent hand calculated results.
Note that joints 2 and 5 are in the same location as are joints 3 and 8. Joints 2 and 5 are constrained with an equal constraint for all degrees of freedom except Ry. Joints 3 and 8 are constrained in a similar manner. The equal constraint creates the continuity between area objects 1 and 2 and allows for the center hinge of the three-hinge arch. The load P is applied as joint loads and is equally split between joints 2, 3, 5 and 8.
Joints 1 and 6 have Ux, Uy and Uz restraints. Joints 4 and 7 have Ux and Uz restraints. Keeping the Uy degree of freedom free at joints 4 and 7 avoids imposing any local Poisson’s effect on the analysis and is consistent with the independent hand analysis.
Buckling is ignored in this problem by setting the area object stiffness modifiers for m11, m22 and m12 bending equal to 1000.

Tested Features

•  Static nonlinear analysis of shell structure with large axial displacements using this model P-Delta plus large displacements option
•  Joint constraints

App

Object Link: https://openbrim.org/objidtrrm1biyp65ef8yct2sc9.project

Library

Object Link: https://openbrim.org/objid21eaoi2n7g64w9hv7kqu85.libobj