Bumper structure

4:

• The bumper structure of claim 1,
• wherein the intermediate web comprises the second material, and
• wherein a reinforcing plate comprising metal is fixed to each of a surface of a corner formed by the front flange and the upper web and a surface of a corner formed by the front flange and the lower web, and
• wherein the reinforcing plate is bent into a hook shape along each corner.

5:

• The bumper structure of claim 1, wherein the first material and second material satisfy an equation:
• t2≦(ρ1/ρ2)·t1,
• wherein
• the thickness of each web comprising the second material is t2, and a thickness of a part comprising the first material is t1.

6:

• The bumper structure of claim 1, wherein the first material and second material satisfy an equation:
• t2·σy2)/(t1·σy1)≧0.5,
• wherein
• the thickness of each web comprising the second material is t2, the thickness of a part comprising the first material is t1, the yield stress of the first material is σy1, and the yield stress of the second material is σy1.

7:

• The bumper structure of claim 2, wherein the first material and second material satisfy an equation:
• t2≦(ρ1/ρ2)·t1,
• wherein
• the thickness of each web comprising the second material is t2, and a thickness of a part comprising the first material is t1.

8:

• The bumper structure of claim 3, wherein the first material and second material satisfy an equation:
• t2≦(ρ1/ρ2)·t1,
• wherein
• the thickness of each web comprising the second material is t2, and a thickness of a part comprising the first material is t1.

9:

• The bumper structure of claim 4, wherein the first material and second material satisfy an equation:
• t2≦(ρ1/ρ2)·t1,
• wherein
• the thickness of each web comprising the second material is t2, and a thickness of a part comprising the first material is t1.

10:

• The bumper structure of claim 2, wherein the first material and second material satisfy an equation:
• (t2·σy2)/(t1·σy1)≧0.5,
• wherein
• the thickness of each web comprising the second material is t2, the thickness of a part comprising the first material is t1, the yield stress of the first material is σy1, and the yield stress of the second material is σy1.

11:

• The bumper structure of claim 3, wherein the first material and second material satisfy an equation:
• (t2·σy2)/(t1·σy1)≧0.5,
• wherein
• the thickness of each web comprising the second material is t2, the thickness of a part comprising the first material is t1 the yield stress of the first material is σy1, and the yield stress of the second material is σy1.

12:

• The bumper structure of claim 4, wherein the first material and second material satisfy an equation:
• (t2·σy2)/(t1·σy1)≧0.5,
• wherein
• the thickness of each web comprising the second material is t2, the thickness of a part comprising the first material is t1, the yield stress of the first material is σy1, and the yield stress of the second material is σy1.