【单选题】For the columns with the same length, material, constraint conditions and cross-sectional area, etc., the stability of which kind of shape of cross-section (see the following figures)is best ? . And t...
【单选题】In the case that the cross-sectional area, support conditions, materials and other conditions are all the same for columns, which kind of cross-sectional shape shown in the figure will get the best st...