哪里定义梁截面

Section definitions are contained within the bulk data section of the input file. A section definition begins with the statement BEGIN,HYPRBEAM,NAME and ends with the statement END,HYPRBEAM. Section definitions are referenced from a PBARL or PBEAML definition through the NAME field. The NAME entered on the PBARL or PBEAML definition must match the NAME following the BEGIN,HYPRBEAM, statement.

The section is defined by a 2-D finite element mesh. The finite element mesh is composed of nodes (denoted by GRIDS entries), which are connected by 2, 3, 4, 6 or 8 noded elements (denoted by CSEC2, CSEC3, CSEC4, CSEC6, or CSEC8 entries, respectively). These elements reference PSEC entries; these provide a material reference for all elements and thickness information for the 2-noded CSEC2 elements.

但是我实际操作起来根本没有看到这些元素，求高人指点下，最好附上截图。