US3922899A - Method of forming sandwich materials - Google Patents

Method of forming sandwich materials Download PDF

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Publication number
US3922899A
US3922899A US486428A US48642874A US3922899A US 3922899 A US3922899 A US 3922899A US 486428 A US486428 A US 486428A US 48642874 A US48642874 A US 48642874A US 3922899 A US3922899 A US 3922899A
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United States
Prior art keywords
sheets
sandwich
forming
skin
panel
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Expired - Lifetime
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US486428A
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English (en)
Inventor
Maurice Henri Louis Fremont
Jean-Francois Denis
Serve Yvan Dzalba-Lyndis
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Airbus Group SAS
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Airbus Group SAS
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D47/00—Making rigid structural elements or units, e.g. honeycomb structures
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
    • Y10T428/24149—Honeycomb-like

Definitions

  • the present invention relates to a method of forming sandwich materials.
  • this spacing element may be either a corrugated element as used in the materials employed by the Applicant under the trade-name Norsial", or a honeycomb type of element as used in the materials employed by the Applicant under the tradename Nida".
  • the neutral or zero-stress fibre passes midway through the thickness of the material, the ten sile and compressive stresses in the two skins are of equal and opposite values, and therefore a knowledge of these values can determine the magnitude of the deformation which can be applied to the panel.
  • the present invention provides a method of forming sandwich materials of the above-mentioned kind, made of oxidizable metals, that overcomes the drawbacks of the prior art.
  • the area subjected to forming stresses is heated locally in such manner that the strength properties of the skin metals governing the permissible stress limits in that area are constantly monitored without the structure as a whole being subjected to oxidation.
  • FIGS. 1 and 2 are sectional side elevation views of Norsial and Nida type sandwich panels, respectively, in which the neutral fibre (x-y) lies in the median plane through the thickness of the panel;
  • FIGS. 3 and 4 are illustrations corresponding to FIGS. 1 and 2, for the case where the neutral fibre (x-y) is offset and does not lie in the median plane through the thickness of the panel;
  • FIGS. 5 and 6 are diagrammatic illustrations showing the stress distribution when a sandwich panel is subjected to bending and tension respectively;
  • FIG. 7 is a graph for illustrating the local buckling phenomenon in a sandwich panel
  • FIG. 8 is a graph showing the effect of oxidation on a metal oxidizable in free air, as a function of time and temperature;
  • FIG. 9 diagrammatically illustrates a first possible arrangement for performing the subject method of this invention.
  • FIG. 10 is a graph in which the strength properties of a titanium alloy are plotted against temperature
  • FIG. 11 is a micrographic image of the effect of oxidation under protracted heat in an assembly of titanium alloy sheets
  • FIG. 12 is a micrographic image of the effect of oxidation under heat in a titanium alloy assembly treated in accordance with the present invention.
  • FIG. 13 diagrammatically illustrates an alternative possible arrangement for performing the subject method of this invention.
  • FIGS. 1 and 2 represent equal stresses T and C for the case where the neutral fibre x-y lies at equal distances r from the external faces 1 and 2 of Norsial and Nida type panels respectively, and FIGS. 3 and 4 represent unequal stresses T and C for the case where the neutral fibre x-y is offset in relation to the median planes of said panels).
  • oxidizable parts especially titanium or titanium alloy parts
  • the forming of oxidizable parts is facilitated if it can be carried out under heat; for in addition to the fact that the rise in temperature improves the basic strength characteristics, it enables the elastic restoring or resilience effect, which is particularly strong in such materials when they are cold, to be avoided.
  • the temperature must be high (in excess of 600C) and it is wellknown that at such temperatures all these oxidizable metals are very seriously contaminated by the atmosphere, resulting in a notably diminished resisting section and in the appearance of oxidized cracks.
  • a conventional forming operation would require a fairly long time during which oxidation and contamination would develop by the process shown in FIG.
  • Curves I, II, III and IV in FIG. 8 correspond to heating times of /2 hour, 1 hour, 2 hours and 4 hours respectively, and it may be noted that the depth of oxidization as a function of temperature and time does indeed vary between about 0.03 mm and 1.1 mm.
  • the forming methodaccording to this invention enables all the drawbacks mentioned hereinbefore to be overcome.
  • the subject method of the invention firstly allows of very substantially delaying the onset of local buckling of the compressed inner skin and therefore increases the forming possibilities for any given panel, and secondly authorizes the forming of oxidizable parts, and especially titanium alloy parts, in very short times during which oxidation has very little chance to develop, even without gaseous protection. It should be noted that such short-time forming by no means implies high deformation speeds, but quite the opposite, thereby enabling advantage to be taken of the relaxation phenomena well-known in metallurgy.
  • this method is characterized by the fact that it consists in heating the skins of a metal sandwich panellocally and differentially in such manner as to ensure that the tensile and compression stresses engendered therein during forming are optimal having regard for the strength characteristics of the metals in question.
  • the local heating zone is proximate the instantaneous deformation zone
  • the forming is carried out by applying the panel against a rotatable former and by providing local heating means in immediate proximity to the points at which the panel to be formed is tangential to said former;
  • the temperature of the hotter skin is approximately 770C, thereby providing a modulus of elasticity of about 6200 hb, and the temperature of the colder" skin is approximately 480C, thereby providing a modulus of elasticity in the region of 8500 hb.
  • the invention likewise relates to arrangements and means for performing the said method, which arrangements are described hereinbelow for exemplary purposes with reference to FIGS. 9 and 13.
  • FIG. 9 illustrates a first way of performing the subject method of this invention.
  • the panel to be formed 3 is placed with its inner face 7 against any convenient rotating former 4.
  • Local heating means 5, such as an iodine vapour or infrared-tube radiator heats the metal locally on the outer skin 6, in proximity to the line of instantaneous deformation, that is to say at the points where the panel to be formed is tangential to the former.
  • a roller-type restraining device 8 prevents the panel from lifting, and possible tensioning means 9 exert a traction on the panel in order to produce additional overall stretching.
  • the surface of former 4 can be coated at 10 with insulating substances such as asbestos or melted ceramic, or alternatively with metals like copper or aluminium so that the good heat-conducting properties thereof may ensure optimum heat distribution through the panel.
  • the Applicant has been able to make a circular cylinder with an inner diameter of I00 mm, made of welded Norsial sandwich material consisting of a corrugated web in 0.15 mm-thick sheet with corrugations pitched at 6 mm and two 0.3 mmthick skins in TA6V4 titanium alloy (6% of aluminium and 4% of vanadium).
  • the panel had a total thickness of 4.3 mm and the wrapping rate was 6 mm per minute.
  • the local heating was providedby an iodine-vapour radiator with a linear heating zone, positioned in such manner that the area heated on the outer skin 6 was a generatrix of the cylinder approximately 3 mm wide.
  • the temperature noted on the heated outer skin was 770C and that of the inner skin in contact with the former (which was made of insulating material) was 480C.
  • the inner cooled skin is compressed to 8500 hb at 480C and the downward shift of the neutral-fibre surface then corresponds to the ratio 8500 hb/6200 hb or 1.37, as schematically illustrated in FIGS. 3 and 4.
  • FIG. 11 shows for exemplary purposes, in the case of 0.27 mm and 0.14 mm thick TA6V4 titanium alloy, the corrosion effect obtained in air during protracted heating at 800C.
  • the micrographic image shows clearly, with its magnification of 125 times, that the oxidized layer is very thick.
  • FIG. 12 which shows the joining area of other such sheet metals of similar nature forming a sandwich panel processed by the subject method of this invention
  • FIG. 12 clearly reveals the thinness of the oxidized layer even though the image is magnified 340 times in this case.
  • FIG. 13 shows an arrangement similar to that in FIG. 9, in which the rotating former 11 is non-cylindrical and the panel 3 is heated by a radiator 5 having infrared tubes and is restrained by a thrust roller 12.
  • a method of forming a metallic panel sandwich comprising two thin metal sheets maintained in mutually spaced relationship by a spacer element of honeycomb structure, corrugated elements, or the like. wherein the said method includes:

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Laminated Bodies (AREA)
  • Shaping Metal By Deep-Drawing, Or The Like (AREA)
  • Forging (AREA)
  • Panels For Use In Building Construction (AREA)
  • Bending Of Plates, Rods, And Pipes (AREA)
US486428A 1973-07-10 1974-07-08 Method of forming sandwich materials Expired - Lifetime US3922899A (en)

Applications Claiming Priority (1)

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FR7325292A FR2237435A5 (es) 1973-07-10 1973-07-10

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DE (1) DE2432929C3 (es)
FR (1) FR2237435A5 (es)
GB (1) GB1433306A (es)

Cited By (25)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4583935A (en) * 1984-10-29 1986-04-22 The Boeing Company Apparatus for forming thermoplastic laminates into major sections
FR2577152A1 (fr) * 1985-01-24 1986-08-14 Messerschmitt Boelkow Blohm Dispositif de fixation d'un element de construction deformable elastiquement et en forme de plaque
US4826420A (en) * 1984-10-29 1989-05-02 The Boeing Company Apparatus for forming thermoplastic laminates into major sections
WO1996007492A1 (en) * 1994-09-02 1996-03-14 Georg Eknes Industrier A/S Process and system for bending of a cellular sheet
US6415639B1 (en) * 1997-07-02 2002-07-09 Trumpf Maschinen Austria Gmbh & Co. Kg Laser-assisted bending method
US20120067100A1 (en) * 2010-09-20 2012-03-22 Ati Properties, Inc. Elevated Temperature Forming Methods for Metallic Materials
US8652400B2 (en) 2011-06-01 2014-02-18 Ati Properties, Inc. Thermo-mechanical processing of nickel-base alloys
US8707747B1 (en) * 2012-12-14 2014-04-29 Rohr, Inc. Forming a shaped sandwich panel with a die and a pressure vessel
US8834653B2 (en) 2010-07-28 2014-09-16 Ati Properties, Inc. Hot stretch straightening of high strength age hardened metallic form and straightened age hardened metallic form
US9050647B2 (en) 2013-03-15 2015-06-09 Ati Properties, Inc. Split-pass open-die forging for hard-to-forge, strain-path sensitive titanium-base and nickel-base alloys
US9192981B2 (en) 2013-03-11 2015-11-24 Ati Properties, Inc. Thermomechanical processing of high strength non-magnetic corrosion resistant material
US9206497B2 (en) 2010-09-15 2015-12-08 Ati Properties, Inc. Methods for processing titanium alloys
US9255316B2 (en) 2010-07-19 2016-02-09 Ati Properties, Inc. Processing of α+β titanium alloys
US9523137B2 (en) 2004-05-21 2016-12-20 Ati Properties Llc Metastable β-titanium alloys and methods of processing the same by direct aging
US9777361B2 (en) 2013-03-15 2017-10-03 Ati Properties Llc Thermomechanical processing of alpha-beta titanium alloys
US9796005B2 (en) 2003-05-09 2017-10-24 Ati Properties Llc Processing of titanium-aluminum-vanadium alloys and products made thereby
US9869003B2 (en) 2013-02-26 2018-01-16 Ati Properties Llc Methods for processing alloys
US9873237B2 (en) 2008-05-09 2018-01-23 Thyssenkrupp Steel Europe Ag Method for forming a crimping fold in a multi-layer composite material and multi-layer composite material having at least one crimping fold
CN108080476A (zh) * 2018-01-11 2018-05-29 张跃 一种弧形钎焊夹芯面板成型方法
US10053758B2 (en) 2010-01-22 2018-08-21 Ati Properties Llc Production of high strength titanium
US10094003B2 (en) 2015-01-12 2018-10-09 Ati Properties Llc Titanium alloy
US10435775B2 (en) 2010-09-15 2019-10-08 Ati Properties Llc Processing routes for titanium and titanium alloys
US10502252B2 (en) 2015-11-23 2019-12-10 Ati Properties Llc Processing of alpha-beta titanium alloys
US10513755B2 (en) 2010-09-23 2019-12-24 Ati Properties Llc High strength alpha/beta titanium alloy fasteners and fastener stock
US11111552B2 (en) 2013-11-12 2021-09-07 Ati Properties Llc Methods for processing metal alloys

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0078891B1 (de) * 1981-10-07 1986-01-29 Dornier Gmbh Verfahren und Einrichtung zur Biegeumformung von Paneelen, insbesondere für die Beplankung der Zelle von Luftfahrzeugen
FR2542668B1 (fr) * 1983-03-15 1986-06-20 Claude Morin Procede de fabrication d'un element a surface courbe a partir d'une planche rigide d'un materiau du type " nid d'abeilles " et produit obtenu
DE4218212A1 (de) * 1992-06-03 1993-12-09 Bayerische Motoren Werke Ag Umformverfahren für Sandwich-Platten
EP0575646A1 (en) * 1992-06-22 1993-12-29 Aliteco Ag A method and a device for forming various workpieces

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US622282A (en) * 1899-04-04 Metal-plate-bending machine
US2737224A (en) * 1951-12-10 1956-03-06 Boeing Co Apparatus for forming sheet metal
US3788117A (en) * 1972-06-19 1974-01-29 Mc Donnell Douglas Corp Method of forming honeycomb

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US622282A (en) * 1899-04-04 Metal-plate-bending machine
US2737224A (en) * 1951-12-10 1956-03-06 Boeing Co Apparatus for forming sheet metal
US3788117A (en) * 1972-06-19 1974-01-29 Mc Donnell Douglas Corp Method of forming honeycomb

Cited By (39)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4583935A (en) * 1984-10-29 1986-04-22 The Boeing Company Apparatus for forming thermoplastic laminates into major sections
US4826420A (en) * 1984-10-29 1989-05-02 The Boeing Company Apparatus for forming thermoplastic laminates into major sections
FR2577152A1 (fr) * 1985-01-24 1986-08-14 Messerschmitt Boelkow Blohm Dispositif de fixation d'un element de construction deformable elastiquement et en forme de plaque
WO1996007492A1 (en) * 1994-09-02 1996-03-14 Georg Eknes Industrier A/S Process and system for bending of a cellular sheet
US6415639B1 (en) * 1997-07-02 2002-07-09 Trumpf Maschinen Austria Gmbh & Co. Kg Laser-assisted bending method
US9796005B2 (en) 2003-05-09 2017-10-24 Ati Properties Llc Processing of titanium-aluminum-vanadium alloys and products made thereby
US9523137B2 (en) 2004-05-21 2016-12-20 Ati Properties Llc Metastable β-titanium alloys and methods of processing the same by direct aging
US10422027B2 (en) 2004-05-21 2019-09-24 Ati Properties Llc Metastable beta-titanium alloys and methods of processing the same by direct aging
US9873237B2 (en) 2008-05-09 2018-01-23 Thyssenkrupp Steel Europe Ag Method for forming a crimping fold in a multi-layer composite material and multi-layer composite material having at least one crimping fold
US10053758B2 (en) 2010-01-22 2018-08-21 Ati Properties Llc Production of high strength titanium
US10144999B2 (en) 2010-07-19 2018-12-04 Ati Properties Llc Processing of alpha/beta titanium alloys
US9765420B2 (en) 2010-07-19 2017-09-19 Ati Properties Llc Processing of α/β titanium alloys
US9255316B2 (en) 2010-07-19 2016-02-09 Ati Properties, Inc. Processing of α+β titanium alloys
US8834653B2 (en) 2010-07-28 2014-09-16 Ati Properties, Inc. Hot stretch straightening of high strength age hardened metallic form and straightened age hardened metallic form
US10435775B2 (en) 2010-09-15 2019-10-08 Ati Properties Llc Processing routes for titanium and titanium alloys
US9624567B2 (en) 2010-09-15 2017-04-18 Ati Properties Llc Methods for processing titanium alloys
US9206497B2 (en) 2010-09-15 2015-12-08 Ati Properties, Inc. Methods for processing titanium alloys
CN103118815A (zh) * 2010-09-20 2013-05-22 Ati资产公司 金属材料的高温形成方法
US20120067100A1 (en) * 2010-09-20 2012-03-22 Ati Properties, Inc. Elevated Temperature Forming Methods for Metallic Materials
US10513755B2 (en) 2010-09-23 2019-12-24 Ati Properties Llc High strength alpha/beta titanium alloy fasteners and fastener stock
US9616480B2 (en) 2011-06-01 2017-04-11 Ati Properties Llc Thermo-mechanical processing of nickel-base alloys
US10287655B2 (en) 2011-06-01 2019-05-14 Ati Properties Llc Nickel-base alloy and articles
US8652400B2 (en) 2011-06-01 2014-02-18 Ati Properties, Inc. Thermo-mechanical processing of nickel-base alloys
US8707747B1 (en) * 2012-12-14 2014-04-29 Rohr, Inc. Forming a shaped sandwich panel with a die and a pressure vessel
US9869003B2 (en) 2013-02-26 2018-01-16 Ati Properties Llc Methods for processing alloys
US10570469B2 (en) 2013-02-26 2020-02-25 Ati Properties Llc Methods for processing alloys
US10337093B2 (en) 2013-03-11 2019-07-02 Ati Properties Llc Non-magnetic alloy forgings
US9192981B2 (en) 2013-03-11 2015-11-24 Ati Properties, Inc. Thermomechanical processing of high strength non-magnetic corrosion resistant material
US10370751B2 (en) 2013-03-15 2019-08-06 Ati Properties Llc Thermomechanical processing of alpha-beta titanium alloys
US9777361B2 (en) 2013-03-15 2017-10-03 Ati Properties Llc Thermomechanical processing of alpha-beta titanium alloys
US9050647B2 (en) 2013-03-15 2015-06-09 Ati Properties, Inc. Split-pass open-die forging for hard-to-forge, strain-path sensitive titanium-base and nickel-base alloys
US11111552B2 (en) 2013-11-12 2021-09-07 Ati Properties Llc Methods for processing metal alloys
US10094003B2 (en) 2015-01-12 2018-10-09 Ati Properties Llc Titanium alloy
US10619226B2 (en) 2015-01-12 2020-04-14 Ati Properties Llc Titanium alloy
US10808298B2 (en) 2015-01-12 2020-10-20 Ati Properties Llc Titanium alloy
US11319616B2 (en) 2015-01-12 2022-05-03 Ati Properties Llc Titanium alloy
US11851734B2 (en) 2015-01-12 2023-12-26 Ati Properties Llc Titanium alloy
US10502252B2 (en) 2015-11-23 2019-12-10 Ati Properties Llc Processing of alpha-beta titanium alloys
CN108080476A (zh) * 2018-01-11 2018-05-29 张跃 一种弧形钎焊夹芯面板成型方法

Also Published As

Publication number Publication date
FR2237435A5 (es) 1975-02-07
DE2432929C3 (de) 1979-10-25
GB1433306A (en) 1976-04-28
DE2432929B2 (de) 1979-02-15
DE2432929A1 (de) 1975-01-30

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