Sound-absorbing panels comprising a core consisting of connected cells, wherein some of the cell walls have openings

A unit wall, panel technology, used in other home appliances, sound insulation, building components, etc.

Inactive Publication Date: 2019-04-16
3M INNOVATIVE PROPERTIES CO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Fiber absorption is very effective above 2000Hz, but requires very thick (over 50mm) layers for absorption below 1400Hz
Helmholtz resonator designs are effective at absorbing low frequency sound, but the need for a cavity of sufficient volume often results in thicknesses exceeding 40mm

Method used

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  • Sound-absorbing panels comprising a core consisting of connected cells, wherein some of the cell walls have openings
  • Sound-absorbing panels comprising a core consisting of connected cells, wherein some of the cell walls have openings
  • Sound-absorbing panels comprising a core consisting of connected cells, wherein some of the cell walls have openings

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1- Embodiment 4

[0357] Commercial modeling software (acoustics software module available from COMSOL, Inc., Burlington, MA under the trade designation "COMSOL MULTIPHYSICS (Finite Element Method Multiphysics Modeling and Analysis)") The acoustic absorption rate of a 14mm hexagon with two wall heights of 10mm and 12.7mm was modeled.

[0358] Printed using a 3-D printer (obtained from 3D Systems, Rock Hill, SC) under the trade designation "PROJET 7000HD SLA" using resin obtained from 3D Systems under the trade designation "VISIJET FLEX" These designs. Figure 14 A pattern of positioned connected hexagons and holes is shown, both modeled and 3D printed. Each sample has two sets of 5 connected hexagons (1460, 1460'), a first pair of 6 connected hexagons (1470, 1470'), a second pair of 6 connected hexagons (1471, 1471'), and three sets of 7 connected hexagons (1480, 1480', 1480"). Print the upper skin to leave holes in the upper skin (see Figure 14 , 1460a to 1480c) (and Table 1 below).

[03...

Embodiment 5 and Embodiment 6

[0364] Honeycomb structure panels with 11.5mm hexagonal cells were prepared by extrusion replication lamination, then channels were processed to make multiple linear cells of 5 hexagons and 7 hexagons, and to make cells of 6 hexagons twice as much. Holes are drilled in the top skin and the bottom skin is laminated in a double belt laminator. The details of the preparation of the acoustic panels are given below.

[0365] - Skin preparation

[0366] A 2.5 inch (6.25 cm) extruder (commercially Obtained under the name "NRM" from Davis-Standard, Pawcatuck, CT) extruded 35% by weight glass fiber-filled polypropylene (GFPP) resin (under the trade designation "XMOD GB306" Obtained from Borealis, Vienna, Austria). An 18 inch (457 mm) film die at 460°F (238°C) was used to drop the extrudate into a 3 roll stack. The extrudate was sandwiched between a first chrome roll at 90°F (32°C) and a second chrome roll at 120°F (49°C) and the second chrome roll was stripped to a chrome roll a...

Embodiment 7 to Embodiment 9

[0375] The skin preparation and honeycomb panel preparation procedures were as described for Example 5.

[0376] -Preparation of acoustic panels

[0377] Three honeycomb panels of approximately 39 inches by 15 inches (1143 by 432 mm) produced as described above were machined in a vertical machining center. Install the panels first using double-sided tape. Then, the top skin was removed, and a 7 / 32 inch (5.55 mm) ball nose end mill was used to remove the honeycomb walls to within 0.015 inches (0.38 mm) of the bottom skin. The pattern of interconnected hexagons is changed to figure 1 The nested hexagonal array shown in . Within the larger 37-hexagonal repeat unit that repeats in these panels are two sets of 5 interconnected hexagons, two sets of 6 interconnected hexagons, and two sets of 7 interconnected hexagons .

[0378] Holes were drilled in the top skin and the hole sizes are given in Table 2 below.

[0379] Table 2

[0380]

[0381] Some of the holes that had...

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Abstract

Panels comprising first and second layers and a core disposed there between, wherein the core has a plurality of walls providing a series of connected cells, wherein some of the cell walls have openings providing fluid communication between a series of at least 3 cells, and wherein the opening in a cell wall has an area that is at least 50 percent of the area of a side of that cell wall. Exemplaryembodiments of panels described herein can be formed articles such as panels, walls, or other parts with curved surfaces. In one exemplary method, panels are shaped via thermoforming. In another exemplary method, panels are shaped via insert molding to provide the article. In another exemplary method, panels are shaped via compression molding to provide the article. The panels are useful for absorbing sound in a designed frequency range.

Description

Background technique [0001] Acoustic panels are sometimes used to reduce noise, for example in motor vehicles and other modes of transportation. There is a need for thin panels that can absorb sound frequencies below 1400 Hz. Fiber absorption is very effective above 2000 Hz, but requires very thick (over 50 mm) layers for absorption below 1400 Hz. Helmholtz resonator designs are effective at absorbing low frequency sound, but the need for a cavity of sufficient volume often results in thicknesses in excess of 40mm. Panels of less than 20 mm thickness, in particular less than 10 mm thickness, which can absorb frequencies below 1400 Hz are particularly suitable in industrial, office and domestic environments. Lightweight panels that can be formed into finished products with curved surfaces should be especially usable for transport. Panels made of recycled thermoplastic material should confer additional sustainability advantages. Contents of the invention [0002] In one as...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B32B3/12B32B3/26E04B1/84E04B1/86G10K11/16G10K11/168G10K11/172B60R13/08
CPCB32B3/12B32B3/266B60R13/08E04B1/86G10K11/172B32B2250/03B32B2250/04B32B2250/05B32B2307/102B32B2307/546B32B2605/003B32B2607/00E04B2001/8428B60N3/044B60R13/0815B60R13/0838B60R13/0861E04B1/8409G10K11/168
Inventor 詹姆斯·M·琼扎罗纳德·W·格德斯托马斯·赫特勒杰弗里·P·卡利什杰森·D·麦克纳尔蒂哈罗德·C·克内希特三世柳泰旭
Owner 3M INNOVATIVE PROPERTIES CO
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