Nonlinear analysis of laminates through a mindlin type shear deformable shallow shell element
- Univ. of Arizona, Tucson, AZ (United States)
- NASA Langley Research Center, Hampton, VA (United States)
Nonlinear structural response of laminated shells is commonly determined by finite element analysis capable of accounting for large displacements and rotations, material anisotropy, transverse shear deformation and doubly curved nature of shell surfaces. Numerous analyses utilize either degenerate (essentially three dimensional isoparametric) elements or shell elements. Although the degenerate elements are suitable for approximating general shell surfaces, they require the use of higher-order numerical integration in the thickness direction to eliminate the problem of {open_quotes}locking{close_quotes} arising from the inability of the shell to bend without stretching and transverse shearing. The higher-order integration schemes, however, are computationally expensive and, worst yet, they result in spurious zero-energy modes. This deficiency is commonly alleviated by introducing explicit integration techniques with the requirement that the determinant of the Jacobian matrix be either constant or vary linearly across the thickness. A natural alternative to the degenerate element is a doubly-curved, shallow triangular shell element because of its conformability to approximate the shell surfaces. With such an element, the stiffness matrix is evaluated explicitly; thus eliminating the spurious zero-energy modes. Although numerous elements of this type exist, many suffer from the {open_quotes}locking{close_quotes} phenomenon. This paper presents a nonlinear analysis capability with a doubly-curved shallow shell element free of {open_quotes}locking{close_quotes}. The {open_quotes}locking{close_quotes} phenomenon is eliminated by explicitly determining the shear and membrane correction factors. The element formulation utilizes the Reissner-Mindlin and Marguerre theories. The analysis of thin and moderately thick composite shells undergoing large displacements and rotations is achieved by using the corotational form of the up-dated Lagrangian formulation.
- OSTI ID:
- 175362
- Report Number(s):
- CONF-950686--
- Country of Publication:
- United States
- Language:
- English
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