doi:10.3850/978-981-08-7920-4_S2-S117-cd

ABSTRACT

For thin-shell structures such as aqueducts, there will be big compressive stress in certain area because of the giant water load and the pre-stressed forces. Therefore its stability problemhas to be considered. Asemi-analytical finite stripmethodwas proposed in this paper for local stability analysis of thin-shell structures. The analytic function was adopted along the axial direction, and the finite element discretization was used along the circumferential direction of aqueduct cross section. According to energy principle, the strain energy of the element can be written as two parts: linear strain energy and the strain energy caused by nonlinear strain. And from the two parts, elastic stiffness matrix and geometric stiffness matrix can be derived. And finally, a characteristic equation can be obtained to describe the local stability of shell structure. According to the above method, the corresponding computer softwarewas developed, and used to calculate two examples: (1) thin plate bearing unidirectional uniform pressure and (2) thin plate bearing unidirectional non-uniform pressure (i.e. under the joint action of uniform pressure and bending moment). The results showthat the solutions by semi-analytic finite method are very close to the analytic solutionswhen subject to in-plane forces. Themethod can be applied to real engineering structures such as cylindrical shell structures like U-shaped aqueducts.

Keywords: Thin-shell structures, Stability analysis, Local stability, Semi-analytic finite strip method, Geometric stiffness matrix, Characteristic equation.

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