Patent Application
20180163401
Blast resistant panels are by no means new. One form of blast panel consists of heavy steel or iron panels. Other impact resistant panels are described in U.S. Pat. Nos. 6,119,422, issued to Theodore E. Clear et al on Sep. 19, 2000, U.S. Pat. No. 6,699,575, issued to Habil J. Dagher et al on Mar. 2, 2004, U.S. Pat. No. 7,406,806, issued to Gerald Hallissy et al on Aug. 5, 2008 and U.S. Pat. No. 8,596,018, issued to Habib J. Dagher et al on Dec. 3, 2013.
The panel described in the Bouhnini et al U.S. Pat. No. 6,119,422 includes layers of gypsum board bonded together with an adhesive mesh.
The Hallissy et al U.S. Pat. No. 7,406,806 describes blast resistant wall units including a layer of structural board, preferably gypsum board or masonry board, a layer of thermoset matrix resin impregnated glass fibers and a further layer of structural board.
The Dagher et al U.S. Pat. No. 6,699,574 discloses a wood sheathing panel incorporating strips of fiber reinforced polymer in the perimeter or corners of the panel. The strips cover an area of 5-50 percent of surface area of the panel.
The Dagher et al U.S. Pat. No. 8,596,018 discloses a blast panel comprising a wood member having a compression side and a tension side. The tension side of the wood number is coated with a layer of fiber reinforced, polymer.
The blast panels described in the above-listed patents would be expensive to manufacture, because they incorporate at least two materials, one of which is a polymer or plastic.
An object of the present invention is to provide a relatively simple blast panel, which is inexpensive and easy to produce.
In its simplest form, the invention relates to a blast panel comprising a plurality of sheets of plywood, which are laminated by gluing the sheets together. Preferably, the laminated sheets are mounted in a metal frame.
The invention is described below with reference to the accompanying drawings, which illustrate a preferred embodiment of the invention, and wherein:
With reference to
The frame 1 is defined by four square cross section steel tubes 4 which are welded together to form a rectangle. The frame 1 need not be rectangular, it could be circular, triangular or any other shape. The strips 2 of angle iron are welded to the inner sides of the frame 1 and to each other, forming a rectangular bracket inside of the frame 1. The plywood sheets 3 are connected to the angle iron strips 2 by carriage bolts 5 extending through the angle iron strips 2 and the laminated plywood sheets 3, and nuts 6. The frame 1 can also be formed by U-shaped channel members (not shown).
As best shown in
Test loads were developed by detonating two batches of ammonium nitrate/fuel oil using bulk industrial explosive mixture. Each shot used a different explosive weight and standoff from the test specimen. Five pressure gauges were mounted on the steel plates on the front of the reaction structure surrounding the specimen. Two laser-based displacement readers were positioned along the vertical center line of the panel for each test. The ranges of gauge readings recorded for positive phase pressure and impulse are presented in Table 1.
The maximum displacement of the panel did not exceed 0.4 inch (10 mm) for either test within the first 150 ms of recorded responses. No permanent panel deformation was observed in either case during post-test inspection, i.e., the panel returned to its original pre-test position as a result of an elastic response. Accordingly, it is reasonable to expect that assemblies with a similar laminate thickness and span can likely sustain significantly higher blast loads than those tested without permanent deformation. The panels can potentially take even higher loads where permanent panel deformation is acceptable, e.g., where panels are to be subjected to a one-time blast event and only need to sustain capacity to allow for personnel egress.
