用ansys写的命令流，受均布荷载的简支梁，跨度为3mm,配有两根钢筋，承受的均布载荷。命令中采用了1/4模型，材料参数详见命令中。(The command flow written by ANSYS is a simply supported beam with a uniform load and a span of 3mm. It is equipped with two steel bars and bears a unifor