A theory for symmetrically laminated, doubly-symmetric composite beams including the effects of anticlastic curvature is presented. Verification of the theory is demonstrated through comparisons with classical plate theory on the buckling loads for eight-layer symmetric angle-ply laminates caused by uniform compression and linearly distributed stress (lateral-torsional buckling). A significant reduction in buckling load is observed when the beams have many layers that are oriented between 25 and 60°C. Closed-form approximations for the new theory for rectangular beams are also presented and the theory is applied to box and I beams. These results show a reduction in the buckling load as compared to other beam theories for the box beams and for strong axis buckling of the I beams when there are many layers with lamination angles between 25 and 60°.
Bibliographical noteFunding Information:
The work presented herein was funded by the National Science Foundation, grant No. CMS-9409526 and the University of Minnesota Graduate School under the McKnight Land-Grant Professorship program.