초록 ▼

A carbon-fiber reinforced plastic sheet is excellent in tensile strength and modulus of elasticity, but defective in impact resistance and fracture toughness. To overcome the defect, two aramid fiber reinforced plastic sheets are adhered to the opposite surfaces of the carbon-fiber reinforced plasti

A carbon-fiber reinforced plastic sheet is excellent in tensile strength and modulus of elasticity, but defective in impact resistance and fracture toughness. To overcome the defect, two aramid fiber reinforced plastic sheets are adhered to the opposite surfaces of the carbon-fiber reinforced plastic sheet to thereby provide a laminated structure and the aramid fibers are skewed at angles of +30.degree. to +60.degree. with respect to the direction of an impact load. This arrangement exhibits an improved shock absorbing efficiency and eliminates surface distortion which would otherwise take place during lamination. Further, a shock-absorbing structure may be produced from combining a plurality of sheets assembled crosswise such that surfaces of the respective sheets lie parallel to the direction of the impact load, and a cutout recess and a bulged portion are formed at an end of at least one sheet adjacent an intersection of the structure. Thus, the one end of the sheet including the cutout recess and the bulged portion undergoes local buckling initiating from the intersection, and thereafter the entire assembly is caused to become buckled. Since complete buckling of the entire structure takes a certain period of time, the impact energy can be absorbed with a reduction of the peak load, whereby the shock-absorbing structure is suitable for use in a crushable zone in aircrafts, automobiles or the like.

대표청구항 ▼

[ What is claimed is:] [1.] A laminated structure of fiber reinforced plastic as at least a planar rib member in a plate form comprising a lower support portion of a floor surface of an airplane for absorbing impact energy from an impact load imposed in a given direction downwardly on the floor surf

[ What is claimed is:] [1.] A laminated structure of fiber reinforced plastic as at least a planar rib member in a plate form comprising a lower support portion of a floor surface of an airplane for absorbing impact energy from an impact load imposed in a given direction downwardly on the floor surface, characterized in thatsaid laminated structure is composed of a carbon-fiber reinforced planar plastic sheet adapted to be disposed with its opposite surfaces lying parallel to the given direction of the impact load, and a pair of aramid fiber reinforced planar plastic sheets adhered to the opposite surfaces of said carbon-fiber reinforced planar plastic sheet,said carbon-fiber reinforced planar plastic sheet has carbon fibers oriented substantially parallel to the given direction of the impact load, andone of said pair of aramid fiber reinforced planar plastic sheets has a first group of aramid fibers oriented at a given angle of 30.degree. to 60.degree. with respect to the given direction of the impact load, and a second group of aramid fibers oriented substantially at an angle of approximately 90.degree. with respect to the given angle of said first group of aramid fibers and intersecting said first group of aramid fibers andthe other of said pair of aramid fiber reinforced planar plastic sheets has a third group of aramid fibers oriented at the same given angle as said first group of aramid fibers with respect to the given direction of the impact load, and a fourth group of aramid fibers oriented at the same angle as said second group of aramid fibers with respect to said third group of aramid fibers and intersecting said third group of aramid fibers.