JP2008039432A - Enclosed mast - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an enclosed mast having a polygonal frustum shape covering a radar of a vessel, capable of reducing RCS, having no adverse effect of the radar on transmission/reception radio waves, and securing a structural strength at corner parts. <P>SOLUTION: Cross sections of the enclosed mast 1 is made into a laminated structure of a skin layer 2 made of integrally formed fiber-reinforced resin and a core member 3. The corner parts 4 of the adjacent skin layers 2 are joined each other by a reinforcement member 5 having a thickness W shorter than wavelengths of the transmission/reception radio waves of the radar in the enclosed mast 1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an enclosed mast that covers a radar of a ship, and more specifically, an enclosed mast that can secure the strength of a corner of a wall material that forms the shape of a polygonal frustum without affecting the radio waves received and transmitted by the radar. About the mast.

  In recent years, as shown in FIG. 5 and FIG. 6, the shape of the enclosed mast 22 is made to be a polyhedron such as an octagonal pyramid in order to improve the stealth with respect to the radio wave of the enclosed mast 22 covering the radar 21 of the ship 20. Various proposals have been made to reduce the radar cross section (RCS) (see, for example, Non-Patent Document 1).

  As shown in FIGS. 7 and 8, these conventional enclosed masts 22, for example, are bonded eight sheets of sandwich-structured panels 23 in which FRP skin plates 24 are bonded to both sides of the core material 3 in order. It is constituted by.

  The joint portion of the panel 23 is configured such that the skin plates 24 adjacent to each other and the core material 3 are joined to each other at the corner portion 25, and the outer surface of the joint end portion of the skin plate 24 is reinforced by an angle 26 made of FPR. .

  However, since electrical discontinuity occurs at the angle 26, there is a problem that the RCS of the enclosed mast 22 increases and the radio waves transmitted and received by the radar 21 are adversely affected.

Moreover, since the strength of the joint portion between the core members 3 in the corner portion 25 is small, there is a problem that the structural strength cannot be secured.
“LPD-17 SAN ANTONIO-class (formerly LX Class)” [online], September 15, 2004, Federation of American Scientist, [searched July 20, 2006], Internet <URL: http: // www.fas.org/man/dod-101/sys/ship/lpd-17.htm>

  The present invention has been made in view of such a problem, and can reduce the RCS, and does not adversely affect the radio waves transmitted and received by the radar, and the corners of the wall material forming the polygonal frustum shape. It is an object of the present invention to provide an enclosed mast that can ensure the structural strength of.

  In order to achieve the above object, the present invention is an enclosed mast that covers a radar of a ship, and the enclosed mast has a polygonal frustum shape made of a wall material formed by laminating a fiber reinforced resin material and a core material. A reinforcing member for connecting the fiber reinforced resin materials on both sides of the core material is provided at each corner of the wall material, and the thickness of the reinforcing member is the wavelength of the radio wave transmitted and received by the radar It is an enclosed mast configured to be smaller than that.

  As the reinforcing member, a metal, a fiber reinforced resin, or a composite thereof can be used, but an insulator whose entire surface is covered with a metal net may be used.

The wall material may be a laminate of at least one frequency selection layer.
As the core material, a honeycomb core or a foam core can be used.

  According to the present invention, an enclosed mast in the shape of a polygonal frustum covering a radar of a ship is bonded to a wall material in which fiber reinforced resin is laminated on both sides of the core material, and the core material is joined at each corner. Since the reinforcing members for connecting the fiber reinforced resin materials on both sides of the two are provided, RCS can be reduced and the structural strength at the corners can be sufficiently secured.

  Further, since the thickness of the reinforcing member is set smaller than the wavelength of the radio wave transmitted and received by the radar, the radio wave transmitted and received by the radar is not adversely affected.

Embodiments of the present invention will be described below with reference to the drawings.
An enclosed mast according to an embodiment of the present invention is shown in FIGS.

  The enclosed mast 1 of the present invention has an octagonal truncated pyramid shape, and its cross section has a structure in which a skin layer 2 made of FRP integrally formed and a core material 3 are laminated in the horizontal direction. . Examples of the material of the skin layer 2 include glass fiber reinforced resin (GFRP) or organic fiber reinforced resin (for example, polyester fiber and aramid fiber). The core material 3 may be a honeycomb core made of aramid fibers or glass fibers, an aramid paper core, a glass fabric core impregnated with resin, or a foam core such as urethane foam.

  And the reinforcement member 5 is inserted so that the corner | angular parts 4 of the skin layer 2 adjacent to radial direction may be connected over the up-down direction of the enclosed mast 1. FIG. The reinforcing member 5 has a flat plate shape made of FRP (GFRP, CFRP, etc.) or a metal material (steel material, aluminum alloy, etc.), and its width (thickness) W is accommodated in the enclosed mast 1. It is set to be smaller than the wavelength of the radar radio wave.

  The reinforcing member 5 can be easily manufactured and arranged by impregnating a support material with a resin when the enclosed mast 1 is manufactured by, for example, an RTM molding method (Resin Transfer Molding).

  In the enclosed mast 1 of the present invention, since the integrally formed skin layer 2 is connected by the reinforcing member 5, the electrical continuity of the enclosed mast 1 can be ensured and RCS can be reduced. Can do. Moreover, since the strength of the joint portion of the core material 3 can be increased by the reinforcing member 5, the structural strength at the corner 4 can be ensured.

  Furthermore, since the thickness W of the reinforcing member 5 is set to be shorter than the wavelength of the radio wave transmitted and received by the radar in the enclosed mast 1, it does not adversely affect the radio wave.

  An enclosed mast according to another embodiment of the present invention is shown in FIGS. In addition, the same code | symbol is attached | subjected to the part which is common in FIG.1 and FIG.2, and description is abbreviate | omitted.

  The enclosed mast 1 has a frequency selective membrane (FSS) 6 laminated in the radial direction of the enclosed mast 1.

  By stacking the FSS 6 in this manner, it is possible to reflect or transmit radio waves having a specific frequency. The structure of the FSS 6 is not particularly limited. For example, the FSS 6 can be configured by arranging metal foils having a specific shape on a dielectric substrate in an array.

  In this embodiment, the reinforcing member 5 is configured by covering the surface of an insulating material such as GFRP with a metallic net such as the metal mesh 7. With this configuration, the electrical continuity of the enclosed mast 1 can be secured and the frequency characteristics can be improved.

  It should be noted that the shape of the enclosed mast 1 and the number of layers and the dimensional ratio of the skin layer 2 and the core material 3 in each of the above embodiments are not limited to those shown in FIGS. 1 can be appropriately changed in accordance with the electrical performance required for 1.

It is a cross-sectional view of the enclosed mast which concerns on embodiment of this invention. It is an enlarged view of the A section in FIG. It is a cross-sectional view of an enclosed mast according to another embodiment of the present invention. It is an enlarged view of the B section in FIG. It is a perspective view of a ship with an enclosed mast. FIG. 6 is an enlarged perspective view of the enclosed mast in FIG. 5. It is a cross-sectional view of a conventional enclosed mast. It is an enlarged view of the C section in FIG.

Explanation of symbols

1 Enclosed Mast 2 Skin Layer 3 Core Material 4 Corner 5 Reinforcing Member 6 FSS
7 Metal Mesh 20 Ship 21 Radar 22 Conventional Enclosed Mast 23 Panel 24 Corner 25 Joint Face 26 Angle

Claims (5)

An enclosed mast covering the ship ’s radar,
The enclosed mast is formed in a polygonal frustum shape by a wall material formed by laminating a fiber reinforced resin material and a core material,
In each corner of the wall material, a reinforcing member for connecting the fiber reinforced resin materials on both sides of the core material is provided,
An enclosed mast configured by setting the thickness of the reinforcing member to be smaller than the wavelength of the radio wave received and transmitted by the radar. The enclosed mast according to claim 1, wherein the reinforcing member is made of metal, fiber reinforced resin, or a composite thereof. The enclosed mast according to claim 1, wherein the reinforcing member is made of an insulator whose surface is covered with a metal mesh. The enclosed mast according to claim 1, 2 or 3, wherein at least one frequency selective layer is laminated on the wall material. The enclosed mast according to claim 1, 2, 3, or 4, wherein the core material is a honeycomb core or a foam core.

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