1.3.19 Shell offset

Product: ABAQUS/Standard

Elements tested

S4R S8R S8RT

Features tested

Shell offset used with the *SHELL SECTION and *SHELL GENERAL SECTION options.

Problem description

The model consists of a plate with a length of 10.0, a width of 1.0, and a thickness of 0.2. The end at 0 is fixed, and all degrees of freedom except the rotation about the -axis are constrained at 10. A rotation –0.1 is applied at 10 for the static analyses. A single shell element with an offset of half the shell's thickness from the midsurface is used to model the plate. The offset is defined with the *SHELL SECTION, OFFSET option or the *SHELL GENERAL SECTION, OFFSET option. Simpson's rule is used for the shell cross-section for all the elements.

Two additional input files (esf4sxsd.inp and esf4sgsb.inp) test the bending of a cantilevered half-cylinder with the *SHELL SECTION, OFFSET option or the *SHELL GENERAL SECTION, OFFSET option. The model has a radius of 5, a length of 20, and a thickness of 0.2. One end is completely constrained, and a uniform upward pressure is applied to all the elements. A general, nonlinear static procedure using NLGEOM is included.

The *ELASTIC option is used to define a material with 3.0 × 10⁶ and 0.25 in all cases.

Results and discussion

The verification of the shell offset results is based on the formulation described in “Transverse shear stiffness in composite shells and offsets from the midsurface,” Section 3.6.8 of the ABAQUS Theory Manual. The results are verified by comparing them to the results obtained from an equivalent model without offset. This equivalent model is defined using the *SHELL SECTION, COMPOSITE or *SHELL GENERAL SECTION, COMPOSITE option, where an extra layer that has a negligible material modulus is added to the model.