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Offset corrugated sandwich construction

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Publication number
USH1481H
USH1481H US08082069 US8206993A USH1481H US H1481 H USH1481 H US H1481H US 08082069 US08082069 US 08082069 US 8206993 A US8206993 A US 8206993A US H1481 H USH1481 H US H1481H
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US
Grant status
Grant
Patent type
Prior art keywords
sandwich
construction
face
offset
sheets
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US08082069
Inventor
Hemen Ray
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
US Secretary of Navy
Original Assignee
US Secretary of Navy
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Grant date

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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B3/00Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form ; Layered products having particular features of form
    • B32B3/26Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form ; Layered products having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer
    • B32B3/28Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form ; Layered products having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer characterised by a layer comprising a deformed thin sheet, i.e. the layer having its entire thickness deformed out of the plane, e.g. corrugated, crumpled
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B31MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
    • B31DMAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER, NOT PROVIDED FOR IN SUBCLASSES B31B OR B31C
    • B31D3/00Making articles of cellular structure, e.g. insulating board
    • B31D3/005Making cellular structures from corrugated webs or sheets
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2250/00Layers arrangement
    • B32B2250/40Symmetrical or sandwich layers, e.g. ABA, ABCBA, ABCCBA

Abstract

A sandwich construction is disclosed that provides alternating offset and jacent corrugated strips secured between upper and lower face sheets. The peaks of one strip are adjacent the troughs of an adjacent strip. The peaks and troughs can have flattened portions and the face sheets can be secured to said portions.

Description

STATEMENT OF GOVERNMENT INTEREST

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

BACKGROUND OF THE INVENTION

The present invention relates generally to sandwich constructions suitable for use in structural and non-structural members, and more particularly to sandwich constructions of low-density cores bonded between thin-gauge, high-strength face sheds for use in a wide range of military, industrial and commercial components.

Sandwich constructions are finding broad application as structural and non-structural members in boats, aircraft, furniture, appliances, and other items requiring high strength, light-weight materials. They typically include face sheets bonded to either side of a low density core and can be made of such materials as metals, plastics or composite fiberglass laminates for rigidity and strength. Among the various core materials are rigid plastic foams, honeycombs, truss-core corrugations and an arrangement of adjacent, inclined rectangular-shaped facets connected by intermediate rows of adjoining parallelagram-shaped facets.

In aircraft design the need for weight efficiency and aerodynamically smooth surfaces under high stress levels has stimulated use of sandwich construction as a possible substitute for the conventional sheet-stringer construction. Notwithstanding the superior weight-efficiency of the sandwich constructions, their general acceptance for critical applications has lagged behind theoretical development primarily because of maintenance problems experienced in service. Honeycomb core sandwich constructions, for instance, are considered to be among the most weight-efficient but, due to their tendency to retain moisture which may become entrapped due to ineffective edge seals or unbonding of face sheets from the core. This may degrade the structural integrity and lead to extensive corrosion and premature failure of components. Experience has shown a significant frequency of repairs on replacements which are very time-consuming and expensive.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide a sandwich construction having a high strength-to-weight efficiency suitable for a broad variety of military, industrial and commercial applications.

Another object is to provide a low-density core sandwich construction in which corrosion and degradation of structural integrity due to retention of moisture is substantially eliminated.

Another object is to provide a sandwich construction in which unbonding of face sheets from the core is substantially reduced or eliminated when heat, pressure or vacuum is applied for purposes of repair.

Still another object is to provide a sandwich construction having a flexible core with structural discontinuities for improved tolerance for damage.

These and other objects of the invention are achieved in a sandwich construction comprising strips of corrugations arranged adjacent one another and alternately offset so that a series of peaks is next to a series of troughs, and vice versa, and contained between upper and lower face sheets. By arranging the strips in this alternating fashion, a plurality of passage-ways from cell to cell is provided. The outer face sheets and the strips are cocured in one operation without any secondary bonding.

The novel features which are believed to be characteristics of the invention, both as to its organization and methods of operation, together with further objects and advantages thereof, will be better understood from the following descriptions in connection with the accompanying drawings in which the presently preferred embodiments of the invention are illlustrated by way of examples. It is to be expressly understood, however, that the drawings are for purposes of illustration and description only and are not intended as a definition of the limits of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a partially cutaway, perspective view of a prior art corrugated sandwich construction;

FIG. 2 shows a similar view of the instant invention, showing offset corrugationns that provide moisture pathways and also showing a series of shape-mandrels, extended from inside the corrugations, that can be used to form the offset pattern;

FIG. 3 shows a front elevation of the offset corrugation construction;

FIG. 4 shows a top view, with the upper face sheet partially cut away of the offset corrugations; and

FIG. 5 shows a cross-sectional view of the offset corrugations, taken along lines V-V of FIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings wherein like referenced characters designate like or corresponding components throughout the several views, there is shown in FIG. 1 a typical prior art corrugated sandwich construction 20 having open cells 23a,b and c alternately adjacent open cells 24a,b, contained between face sheets 21a and b. The only difference between the cells being that cells 23a,b and c have a flat roof section 26 adjacent face sheet 21a and cells 24a,b have a flat roof section 27 adjacent face sheet 21b. Cells 23 and 24 are formed by corrugations, consisting of peaks and troughs, in a core material, which can be various metals, plastics, composites or non-composites, and face sheets 21a and b are bonded to appropriate roof sections 26 and 27, respectively. Under stress, the face sheets may crack or separate from the cells, permitting moisture to accumulate therein, and with time, cause the core material to increase in weight and corrode. The usual procedure for repair entails cleaning out any damage and resealing the face sheets by applying heat and pressure (or vacuum) thereto. This is unreliable and sometimes causes further problems with the face sheets.

Referring now to the inventive embodiment of FIGS. 2 through 5, there is shown a sandwich construction 35 comprising corrugated strips 41 and 43, each having peaks 45 and troughs 47, offset, or out of phase by a predetermined amount, contained between upper and lower face sheets 51a and b, respectively. This offset corrugated construction provides hexagonally shaped cells 55 surrounded on either side by individual triangular cells 58. The material used for a particular core is separated into strips 41, of approximately one-half inch in width and wrapped around a set of mandrels 60,61, as shown in FIG. 2. Strips 41 can be of any suitable size and can depend on the overall size and strength of the sandwich construction. Mandrels 60,61 maintain the desired shape and spacing during attachment of face sheets 51a and b, but are then removed after the cocuring operation. This design allows pathways for any moisture that may find its way into the core. Mandrels 60,61 can be any solid type material, such as TFE or other similar materials, to facilitate removal after curing.

Experimental work with a test sample constructed with this offset corrugated core, as compared to a sample constructed using a prior art design, shows a 56% increase in transverse shear stiffness in the weaker direction (in the direction of corrugation). A comparison of bending stiffness shows no measurable difference between the two.

Finally, while the offset corrugated core sandwich construction has been described with reference to a particular embodiment, it should be understood that the embodiment is merely illustrative as there are numerous variations and modifications which may be made by those skilled in the art. Thus, the invention is to be construed as being limited only by the spirit and scope of the appended claims.

Claims (6)

What I claim is:
1. A sandwich construction comprising:
offset corrugated means having a plurality of substantially parallel cells, each cell being formed by alternating peaks and troughs and having moisture communication with each other adjacent cell; and
face sheet means secured to opposite sides thereof.
2. A sandwich construction as described in claim 1 wherein each said peak is substantially flat.
3. A sandwich construction as described in claim 2 wherein each said trough is substantially flat.
4. A sandwich construction as described in claim 3 wherein said face sheet means is attached to the offset corrugated means at the flat peaks and troughs.
5. A sandwich construction comprising:
adjacent corrugated strips arranged to have peaks of a first strip substantially next to troughs of a second strip to form an offset pattern; and
upper and lower face sheets secured thereto.
6. A sandwich construction as described in claim 5 wherein said corrugated strips are substantially one-half inch wide.
US08082069 1993-06-23 1993-06-23 Offset corrugated sandwich construction Abandoned USH1481H (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US08082069 USH1481H (en) 1993-06-23 1993-06-23 Offset corrugated sandwich construction

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US08082069 USH1481H (en) 1993-06-23 1993-06-23 Offset corrugated sandwich construction

Publications (1)

Publication Number Publication Date
USH1481H true USH1481H (en) 1995-09-05

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ID=22168869

Family Applications (1)

Application Number Title Priority Date Filing Date
US08082069 Abandoned USH1481H (en) 1993-06-23 1993-06-23 Offset corrugated sandwich construction

Country Status (1)

Country Link
US (1) USH1481H (en)

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5598930A (en) * 1995-07-20 1997-02-04 Advanced Wirecloth, Inc. Shale shaker screen
US5971159A (en) * 1993-04-30 1999-10-26 Tuboscope I/P, Inc. Screen assembly for a vibratory separator
US6029824A (en) * 1994-03-30 2000-02-29 Tuboscope I/P, Inc. Screen for vibrating separator
USD425531S (en) 1999-03-29 2000-05-23 Tuboscope I/P, Inc. Screen
US6152307A (en) * 1993-04-30 2000-11-28 Tuboscope I/P, Inc. Vibratory separator screens
US6267247B1 (en) 1993-04-30 2001-07-31 Tuboscope I/P, Inc. Vibratory separator screen
US6269953B1 (en) 1993-04-30 2001-08-07 Tuboscope I/P, Inc. Vibratory separator screen assemblies
US6283302B1 (en) 1993-08-12 2001-09-04 Tuboscope I/P, Inc. Unibody screen structure
US6290068B1 (en) * 1993-04-30 2001-09-18 Tuboscope I/P, Inc. Shaker screens and methods of use
US6325216B1 (en) 1993-04-30 2001-12-04 Tuboscope I/P, Inc. Screen apparatus for vibratory separator
US6371302B1 (en) 1993-04-30 2002-04-16 Tuboscope I/P, Inc. Vibratory separator screens
US6401934B1 (en) 1993-04-30 2002-06-11 Tuboscope I/P, Inc. Ramped screen & vibratory separator system
US6443310B1 (en) 1993-04-30 2002-09-03 Varco I/P, Inc. Seal screen structure
US6450345B1 (en) 1993-04-30 2002-09-17 Varco I/P, Inc. Glue pattern screens and methods of production
US6454099B1 (en) 1993-04-30 2002-09-24 Varco I/P, Inc Vibrator separator screens
US6565698B1 (en) 1993-04-30 2003-05-20 Varco I/P, Inc. Method for making vibratory separator screens
US6607080B2 (en) 1993-04-30 2003-08-19 Varco I/P, Inc. Screen assembly for vibratory separators
US6629610B1 (en) 1993-04-30 2003-10-07 Tuboscope I/P, Inc. Screen with ramps for vibratory separator system
US6669985B2 (en) 1998-10-30 2003-12-30 Varco I/P, Inc. Methods for making glued shale shaker screens
US6736270B2 (en) 1998-10-30 2004-05-18 Varco I/P, Inc. Glued screens for shale shakers

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3542636A (en) * 1965-07-28 1970-11-24 Kurt Wandel Corrugated board
US3574103A (en) * 1968-09-06 1971-04-06 Atomic Energy Commission Laminated cellular material form
US4472473A (en) * 1983-07-01 1984-09-18 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Curved cap corrugated sheet
US4769968A (en) * 1987-03-05 1988-09-13 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Truss-core corrugation for compressive loads
US5028474A (en) * 1989-07-25 1991-07-02 Czaplicki Ronald M Cellular core structure providing gridlike bearing surfaces on opposing parallel planes of the formed core
US5162143A (en) * 1990-03-30 1992-11-10 The United States Of America As Represented By The Administrator, National Aeronautics And Space Administration Core design for use with precision composite reflectors

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3542636A (en) * 1965-07-28 1970-11-24 Kurt Wandel Corrugated board
US3574103A (en) * 1968-09-06 1971-04-06 Atomic Energy Commission Laminated cellular material form
US4472473A (en) * 1983-07-01 1984-09-18 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Curved cap corrugated sheet
US4769968A (en) * 1987-03-05 1988-09-13 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Truss-core corrugation for compressive loads
US5028474A (en) * 1989-07-25 1991-07-02 Czaplicki Ronald M Cellular core structure providing gridlike bearing surfaces on opposing parallel planes of the formed core
US5162143A (en) * 1990-03-30 1992-11-10 The United States Of America As Represented By The Administrator, National Aeronautics And Space Administration Core design for use with precision composite reflectors

Cited By (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6530483B2 (en) 1993-04-30 2003-03-11 Varco I/P, Inc. Unibody structure for screen assembly
US5971159A (en) * 1993-04-30 1999-10-26 Tuboscope I/P, Inc. Screen assembly for a vibratory separator
US6629610B1 (en) 1993-04-30 2003-10-07 Tuboscope I/P, Inc. Screen with ramps for vibratory separator system
US6454099B1 (en) 1993-04-30 2002-09-24 Varco I/P, Inc Vibrator separator screens
US6032806A (en) * 1993-04-30 2000-03-07 Tuboscope I/P, Inc. Screen apparatus for vibratory separator
US6607080B2 (en) 1993-04-30 2003-08-19 Varco I/P, Inc. Screen assembly for vibratory separators
US6152307A (en) * 1993-04-30 2000-11-28 Tuboscope I/P, Inc. Vibratory separator screens
US6267247B1 (en) 1993-04-30 2001-07-31 Tuboscope I/P, Inc. Vibratory separator screen
US6269953B1 (en) 1993-04-30 2001-08-07 Tuboscope I/P, Inc. Vibratory separator screen assemblies
US6565698B1 (en) 1993-04-30 2003-05-20 Varco I/P, Inc. Method for making vibratory separator screens
US6290068B1 (en) * 1993-04-30 2001-09-18 Tuboscope I/P, Inc. Shaker screens and methods of use
US6302276B1 (en) 1993-04-30 2001-10-16 Tuboscope I/P, Inc. Screen support strip for use in vibratory screening apparatus
US6325216B1 (en) 1993-04-30 2001-12-04 Tuboscope I/P, Inc. Screen apparatus for vibratory separator
US6371302B1 (en) 1993-04-30 2002-04-16 Tuboscope I/P, Inc. Vibratory separator screens
US6401934B1 (en) 1993-04-30 2002-06-11 Tuboscope I/P, Inc. Ramped screen & vibratory separator system
US6443310B1 (en) 1993-04-30 2002-09-03 Varco I/P, Inc. Seal screen structure
US6450345B1 (en) 1993-04-30 2002-09-17 Varco I/P, Inc. Glue pattern screens and methods of production
US6283302B1 (en) 1993-08-12 2001-09-04 Tuboscope I/P, Inc. Unibody screen structure
US6029824A (en) * 1994-03-30 2000-02-29 Tuboscope I/P, Inc. Screen for vibrating separator
US5598930A (en) * 1995-07-20 1997-02-04 Advanced Wirecloth, Inc. Shale shaker screen
US5988397A (en) * 1996-02-12 1999-11-23 Tuboscope I/P, Inc. Screen for vibratory separator
US6669985B2 (en) 1998-10-30 2003-12-30 Varco I/P, Inc. Methods for making glued shale shaker screens
US6736270B2 (en) 1998-10-30 2004-05-18 Varco I/P, Inc. Glued screens for shale shakers
USD425531S (en) 1999-03-29 2000-05-23 Tuboscope I/P, Inc. Screen

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Legal Events

Date Code Title Description
AS Assignment

Owner name: UNITED STATES OF AMERICA, THE, AS REPRESENTED BY T

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:RAY, HEMEN;REEL/FRAME:006603/0951

Effective date: 19930622