A kind of displacement mode of spatial beam element considering the effect of warping and distortion

Based on the theory of elasticity and torsional geometry, the displacement mode of a single node 6-degree-of-freedom,low order spatial beam element with the ability to calculate bending distortion was reproduced,and the construction method of Bm_ZY was improved, realizing its application on any cross-section. Furthermore,the accuracy of Gaussian integration was explored through the self-developed ZQFEM finite element program, and the contributions of shear and bending deformations to torsional stiffness were separated. Finally, the influence of cross-sectional shape and wall thickness on buckling distortion was studied through a cantilever beam example, and the reliability of the commercial software Midas Civil was explored. The analysis results indicate that the Bm_ZY element has the ability to analyze the coupling effects of torsion, shear, and bending. Gaussian integration using more than eight points reduced weak integration errors to within 10%. Numerical examples once again confirm that the constrained torsional effect significantly increases the torsional stiffness of the cross-section; The Bm_ZY unit has a exhibits consistent deformation behavior under applied stress.