Front floor panel

A front floor panel of a metal of an automotive body having a floor tunnel formed to be oriented in a longitudinal direction of the automotive body in a center in an automotive width direction of the automotive body, upright flanges disposed left and right formed at a left and right end portions in the automotive width direction to be joined to side sills, and a left and right plane portions formed between the upright flanges disposed left and right and a longitudinal wall portions of the floor tunnel disposed left and right characterized in that,

• the front floor panel has an convex-concave part described below that is formed in a loop-shaped area including an outer edge portion of the plane portion, and has a flat sheet-shaped portion formed in a remaining area except for the loop-shaped area;
• wherein the convex-concave part:
• when based on three reference planes that are a first reference plane, an intermediate reference plane, and a second reference plane that are three planes sequentially arranged in parallel to be spaced from one another, a first unit area and a second unit area that are virtual squares are spread all over with the intermediate reference plane as a reference, and one of two directions along two sides orthogonal to each other of the virtual square is defined as a lateral direction, whereas the other one is defined as a longitudinal direction,
• the first unit area is divided into three at an optional ratio of A:B:A in the lateral direction, as a result, is divided into first divided areas that are two areas divided at a ratio A, and a second divided area that is one area divided at a ratio B,
• the second unit area is divided into three at an optional ratio of A:B:A in the longitudinal direction, as a result, is divided into second divided areas that are two areas divided at the ratio A, and a first divided area that is one area divided at the ratio B,
• with the intermediate reference plane as a reference, the first unit areas and the second unit areas are alternately disposed with respect to the longitudinal direction and the lateral direction respectively, a first reference area having a substantially I shape formed of the adjacent first divided areas, and a second reference area having a substantially I shape formed of the adjacent second divided areas are included,
• the convex-concave part is a shape part having a first area protruding toward the first reference plane from the first reference area, and a second area protruding toward the second reference plane from the second reference area defined on the intermediate reference plane,
• the first area has a first top surface obtained by projecting the first reference area into the first reference plane at either unity or reduction magnification, and a first side surface that connects a contour of the first top surface and a contour of the first reference area, and
• the second area has a second top surface obtained by projecting the second reference area into the second reference plane at either unity or reduction magnification, and a second side surface that connects a contour of the second top surface and a contour of the second reference area.