WO2014021699A1

WO2014021699A1 - Panel

Info

Publication number: WO2014021699A1
Application number: PCT/LV2012/000013
Authority: WO
Inventors: Maris Kesners
Original assignee: Maris Kesners
Priority date: 2012-08-03
Filing date: 2012-08-03
Publication date: 2014-02-06

Abstract

A panel (1) comprises a three-dimensional thin-walled structure with domes (2) arranged in a staggered formation so that every adjacent dome (2) is oppositely directed and transitions gradually into the adjacent dome (2) thus forming an interconnected system of domes (2) arranged in plane or in the shape of the spun surface, the apexes of the domes (2) coming into contact at least from one side with the outer surface of the system. The panel can be used in aerospace engineering, in shipbuilding, automotive industry, carriage engineering, and construction, in audio equipment and in any other branch demanding light and mechanically endurable configurations.

Description

Panel

The invention pertains to multilayer panels with a thin-wall core filling and can be used for the production of various load- bearing and insulating structures in any branch of mechanical engineering.

US3663346 describes an element of a honeycomb panel formed of spherical surfaces. They are orthogonally bounded tubule sections smoothly transitioning into each other and forming an interconnected structure. The structure is complex and requires sophisticated technology to produce.

JP201000655 describes a honeycomb sandwich panel having cell densification at the areas of maximum load (in the centre) thereby increasing the load capacity. Such a method may be used only in cases where the load distribution is precisely predictable. If the load may vary along the surface of the panel, this method is not applicable.

RU2290312 describes a panel with a thin-wall structure formed by truncated opposing pyramids. Thus the invention achieves increased noise attenuation. However, this construction does not improve the mechanical properties of the panel.

In its technical essence, EP0 65719 is most closely related to the present invention. EP0465719 describes a panel with a thin- wall inner structure formed of cells containing domes positioned with bases directed outwards while their apexes are freely positioned within the cells. Thus the mechanical properties of the panel are improved and noise attenuation is increased. However, the domes improve the mechanical properties of the panel only marginally, because their apexes are free within the cells. As the domes are all oriented in the same direction, the structure of the panel results in asymmetric properties with respect to the plane of the domes within the cells. It is the object of this invention to improve the mechanical and acoustical properties of the panel and simultaneously decrease the weight of the structure.

This goal is achieved with a panel comprised of a three- dimensional thin-walled structure of domes arranged in a checker-board pattern so that adjacent domes are oriented in opposite directions and transition gradually into the adjacent dome thus forming an interconnected system. The panel may be formed with a plane or curved surface, while the apexes of the domes contact the outer surface of the system from at least one side.

Schematic illustrations of the panel:

Fig.l - positioning of domes in the panel and panel cross- sections,

Fig.2 - double panel.

Fig.3 - double panel with an insert.

Fig. - panel with divergent cover plates.

Fig.5 - panel with divergent cover plates and variable pitch dome arrangement.

The object of this invention, is achieved by the configuration of the panel 1, comprising a three-dimensional thin-walled structure with domes 2 arranged in a checker-board pattern so that adjacent domes 2 are oriented in opposite directions and transition gradually into the adjacent dome 2 thus forming an interconnected system of domes 2 arranged in a plane or a curved surface, the apexes of the domes coming into contact at least on one side with the cover plate of the system.

The main advantage of the dome construction lies in the fact that the load imposed on the dome 2 transforms into a pressure and tensile load that is evenly distributed across the whole dome. This allows fabrication of structures with a minimal amount of material, which in turn substantially decreases the weight of the structure. Acoustically, sound is repeatedly reflected within the panel and consequently diffused. Hence the sound insulation properties of the panel are improved.

Fig.l. shows the arrangement of domes 2. Adjacent domes 2 are oriented in opposite directions and marked respectively with - and b - "o". Such arrangement of domes, as much as possible, ensures uniform mechanical properties of the panel 1 across the whole area of the panel 1.

Panels 1 may consist of several layers with a corresponding junction (Fig.2.) of dome apexes in each separate layer, or the apexes may be joined by an insert (Fig.3.}. In areas where the load 1 across the surface of the panel varies, panels with alternating cross-sections can be used. They may have a constant (Fig. .) or varying (Fig.5.) pitch in the spacing of the domes 2. The panel may be constructed with a plane or curved surface. Depending on the type and degree of the load, the panel 1 can be closed with system cover plates from one side, or from both sides, along the entire area or only partially.

If necessary, the thickness of the dome walls may be varied to even out the load. For instance, at the transition points from one dome 2 to the oppositely directed one, the walls may be made thicker, thus forming reinforced areas.

In order to decrease the possibility of concentrated stress damaging the domes at contact points with the cover plates, the apexes of the domes may be truncated and/or made thicker than the other areas of the dome. An intermediate layer of glue, solder or other material conforming to the apex of the dome may be provided between the apex and the cover plate. The cover plate may be dimpled to fit the apex of the dome for greater contact area.

The domes can be formed as a cylindrical shell of any curvature, for instance, part of a circle, sinusoid, ellipse, hyperbole and other. Calculations were made to compare properties of dome and honeycomb panels. The dome has a truncated apex with r=4.193 mm and the truncated part is thicker for 0.5 mm, altogethe making 1.5 mm. Wall thickness for the rest of the dome is 1.0 mm and radius 20.05 mm.

The thickness of the honeycomb material is fixed - 1.0 mm. Mesh 1.0 mm, force 10 N.

Table 1 shows parameter calculations for the dome when applying a load at various angles.

Table 2 shows the calculations for the honeycomb when applying a load at various angles.

It is evident that while applying the load on the honeycomb at an angle of 90°' the honeycomb has better parameters than the dome. Once the load angle is changed, it is evident that, the shape of the dome has substantial advantages in comparison with the honeycomb.

The calculations presume that the dome and the honeycomb are made of the same material. In this particular case the mass of the dome is 10.9% smaller than that of the honeycomb.

Table 1

Table 2.

The structure of domes 2 with thin walls may be easily produced by various technological methods. Flexible materials (metals etc.) may be rolled in profiled rollers to any required length. Complex shapes and structures with a variable pitch and/or dome height and spun shapes may be produced by punch-press methods. Thermoplastic polymer materials may be pressed, drawn with air at increased or decreased pressure, cast or in other ways.

It is possible to produce very light and durable masts and various load supporting structures by rolling a band of the rolled structure on a casing, coating it with a reverse wound band and fastening this assembly by soldering, welding or gluing .

If the structure is made of sufficiently light and durable material, very rigid diffusers of acoustic systems in a complex configuration can be produced.

The panel can be used in aerospace engineering, in shipbuilding, automotive industry, carriage engineering, and construction, in audio equipment and in any other branch demanding light and mechanically durable structures.

Claims

A panel comprising a three-dimensional thin-walled structure with domes characterized in that the structure is formed of domes arranged in a staggered formation so that every adjacent dome is oppositely directed and transitions gradually into the adjacent dome thus forming an interconnected system of domes arranged in a plane or curved surface, the apexes of the domes coming into contact at least from one side with the outer surface of the system.