An assumed strain triangular solid shell element with bubble function displacements for analysis of plates and shells

Bubble function displacements are used in conjunction with the assumed strain formulation to construct e:cient triangular solid shell elements tailored for shell analysis. Two versions of 36-DOF triangular elements are presented with di>erent bubble function displacements and the corresponding assumed strain ?elds. In the ?rst version the bubble function displacement is independent of the thickness while in the second version the bubble function varies linearly in the thickness direction. The assumed strain ?elds are carefully selected to alleviate locking e>ect. The ?rst version models curved shells with Aat triangular elements. The second version is e>ective in alleviating the membrane locking and thus allows more accurate modelling of curved shells. Various numerical examples demonstrate the validity and e>ectiveness of the present assumed strain formulation elements with the bubble function displacements