Three aluminium channel sections of US standard extruded dimension are mounted as cantilevers with x-axis symmetry. The flexural bending and shear that arise with applied axial torsion are each considered theoreticall...Three aluminium channel sections of US standard extruded dimension are mounted as cantilevers with x-axis symmetry. The flexural bending and shear that arise with applied axial torsion are each considered theoretically and numerically in terms of two longitudinal axes of loading not coincident with the shear centre. In particular, the warping displacements, stiffness and stress distributions are calculated for torsion applied to longitudinal axes passing through the section’s centroid and its web centre. The stress conversions derived from each action are superimposed to reveal a net sectional stress distribution. Therein, the influence of the axis position upon the net axial and shear stress distributions is established compared to previous results for each beam when loading is referred to a flexural axis through the shear centre. Within the net stress analysis is, it is shown how the constraint to free warping presented by the end fixing modifies the axial stress. The latter can be identified with the action of a ‘bimoment’ upon each thin-walled section.展开更多
On the basis about studying free bending for box beam with rectangular cross_section filled by honeycomb core,supplementary displacements and stresses of restrained bending for such beam were analyzed.The hypothesis f...On the basis about studying free bending for box beam with rectangular cross_section filled by honeycomb core,supplementary displacements and stresses of restrained bending for such beam were analyzed.The hypothesis for separated variables was adopted to solve displacement.According to this,three aspect equations of geometrical,physical and balance were obtained.With Galerkin's method,it is summed up as two_order ordinary differential equations with the attenuation character.Analysis makes clear that attenuation speed of stress is concerned with a big load or a small one,geometric dimensions of cross_section of beam,and physical parameter of material.展开更多
文摘Three aluminium channel sections of US standard extruded dimension are mounted as cantilevers with x-axis symmetry. The flexural bending and shear that arise with applied axial torsion are each considered theoretically and numerically in terms of two longitudinal axes of loading not coincident with the shear centre. In particular, the warping displacements, stiffness and stress distributions are calculated for torsion applied to longitudinal axes passing through the section’s centroid and its web centre. The stress conversions derived from each action are superimposed to reveal a net sectional stress distribution. Therein, the influence of the axis position upon the net axial and shear stress distributions is established compared to previous results for each beam when loading is referred to a flexural axis through the shear centre. Within the net stress analysis is, it is shown how the constraint to free warping presented by the end fixing modifies the axial stress. The latter can be identified with the action of a ‘bimoment’ upon each thin-walled section.
文摘On the basis about studying free bending for box beam with rectangular cross_section filled by honeycomb core,supplementary displacements and stresses of restrained bending for such beam were analyzed.The hypothesis for separated variables was adopted to solve displacement.According to this,three aspect equations of geometrical,physical and balance were obtained.With Galerkin's method,it is summed up as two_order ordinary differential equations with the attenuation character.Analysis makes clear that attenuation speed of stress is concerned with a big load or a small one,geometric dimensions of cross_section of beam,and physical parameter of material.
文摘以热-弹塑性理论为基础,建立了100 mm厚20MnNiMo三维焊接有限元模型,利用ANSYS有限元程序分析了4种约束方式对特厚板焊接残余应力的影响,并通过盲孔法对部分模拟结果进行了试验验证.计算结果表明,约束位置的增加可以使焊接接头残余应力变大.随着约束位置的增加,焊缝区横向应力和热影响区纵向应力由压应力变成拉应力.约束位置越多,残余应力越大,焊接变形越小.模拟结果中,方案A试板边部翘曲变形最大,总变形量为39 mm,方案D变形最小,变形量为0.8 mm.
