Local instability of symmetrical rectangular tubes under axial compression
This is a 1939 NACA technical report from the NASA Technical Reports Server, produced by the National Advisory Committee for Aeronautics for engineers studying aircraft structures. Its pictures are engineering line drawings and graphs: a rectangular tube cross-section with dimension and wall-thickness callouts, an isometric sketch of a column buckling locally with dashed deformed outlines, and a plotted curve of minimum torsional rigidity against width-to-height ratio. A designer might take from them the clean technical diagram style, dashed lines for deformed shapes, and labelled dimension arrows.
