Functional Material Arresting System

Abstract

The present invention relates to a vehicle arresting system comprising an arrester bed of compressible foam material having bulk compressive strength and a central longitudinal axis extending from a front end to an opposite rear end, the arrester bed comprising an assembly of prefabricated blocks arranged in an even number of linear lanes of the prefabricated blocks, half of the sets being positioned to the left of the central longitudinal axis of the arrester bed and half of the sets being positioned to the right, each linear lane of the prefabricated blocks being inclined at an angle α toward the central longitudinal axis of the arrester bed, where 0°<α≦30°.

Description

[Technical Field]

[0001] The present invention relates to an engineered material arresting system (EMAS) bed for slowing and steering vehicles / aircraft that cannot stop under their own power. More precisely, the invention relates to an EMAS bed that has a guidance effect on the vehicle that enters the bed. [Background technology]

[0002] A runway overrun is a landing accident with potentially fatal consequences caused by an aircraft failing to stop before reaching the end of the runway. Typical causes of runway overruns are pilot error, bad weather, and / or technical failure of the aircraft.

[0003] An Advanced Material Arresting System (EMAS) is a system installed at the end of a runway to help stop aircraft that are unable to stop before reaching the end of the runway. EMAS design typically involves optimizing the bed geometry to provide the best overall fleet performance. Fleet optimization requires compromises, resulting in suboptimal performance for some aircraft. While shallower beds and softer materials improve stopping performance for smaller aircraft, larger aircraft require the opposite characteristics. As a result, there is a strong incentive to develop EMAS concepts that can improve the performance of mixed fleets of large and small aircraft. Because most airports serve a wide range of aircraft, EMAS should advantageously be designed to stop aircraft of very different sizes, ranging from as little as 12 metric tons to 450 metric tons. Aircraft can have very different tire sizes, ranging from less than 50 cm in diameter to over 145 cm in diameter. EMAS are designed specifically for the typical fleet of aircraft served by a particular airport and are tailored to the space available beyond the end of the runway.

[0004] Prior art EMAS typically consist of a large, shallow bed of absorbent material that engages the aircraft's tires and absorbs the aircraft's kinetic energy, bringing the aircraft to a controlled stop. Commercially available EMAS use different types of construction, but the primary absorbent material is typically cementitious foam blocks or glass foam aggregate.

[0005] No. 3,967,704 describes a safety device for rapidly arresting the movement of vehicles such as airplanes and automobiles by forming a deceleration bed of crushable material adjacent to the vehicle tracks. A foam is formed from an aminoplastic resin composition and placed in the bed adjacent to the vehicle tracks where it is cured in place to provide a compressive strength of 15 to 50 psi (0.10 to 0.34 MPa) and a compressive strength of 0.25 to 10 pounds per cubic foot (4 to 160 kg / m). 3 ) to produce a non-elastic hardened foam having a density of 1000 psi. This document describes an exemplary embodiment of a bed having a uniform thickness at the center and having sloping sides to provide a centering effect for the aircraft using it.

[0006] US 5,885,025 describes a vehicle arresting bed constructed from multiple blocks of porous concrete with a predetermined compressive gradient strength so that the aircraft's landing gear experiences drag effective for slowing various types of aircraft while providing deceleration within safe limits. The arresting bed typically includes an entrance area of ​​increasing depth, from 9 to 24 inches (23 to 61 cm), formed from blocks with a first compressive gradient strength. A second area, tapering toward the first area and increasing in depth to 30 inches (76 cm), is formed from blocks with a greater compressive gradient strength. Thus, aircraft experience increased drag while passing through the bed, providing stopping capabilities suitable for a variety of aircraft. A protective hard coat layer of porous concrete, stronger than the blocks, overlies the blocks, allowing service personnel to walk on the bed without damage. The arresting bed system may also be provided in alternative configurations, such as a bed formed from aggregate containing pieces of porous concrete, with or without interspersed pieces of other compressible materials, covered by a hard coat layer. This document further discloses an exemplary embodiment in which the block cell cement of the first row has a lower compressive gradient strength than the blocks of the subsequent rows in order to increase the longitudinal retarding effect of the aircraft.

[0007] US 10,458,073 B2 discloses a system and method for stopping an aircraft. In certain embodiments, the system and method may be useful for stopping light aircraft, since light aircraft typically do not have the weight to penetrate available EMAS systems. The system is generally provided as a structure having a suspension layer of energy-absorbing material. The lower part of the system may have a lower strength that is used as a method of suspending the stronger / more energy-absorbing upper part of the system.

[0008] The concept of using prefabricated blocks of foam glass material was explored by the National Transportation Research Council and documented in ACRP Report 29 [1]. Glass foam block material was determined to have many desirable EMAS properties, including a nearly ideal compressive stress-strain curve, chemical inertness, low strain rate dependence, environmental durability, and flammability. This report describes design concepts involving glass foam arranged in prefabricated blocks or assembled on-site at the runway. The block concept includes joints and seams between blocks, but a constructed approach can be used to provide a continuous surface. Because glass foam is typically manufactured in relatively small block or board shapes, this report envisioned smaller boards being glued together to create larger blocks or constructed in layers to create a monolithic bed.

[0009] ACRP Report 29 also describes a modular design in which multiple layers of compressible foam material with different compressive strengths are glued together to vary the depth, with softer layers located near the surface of the bed and harder layers located near the bottom. This concept was intended to help improve the performance of arrestor beds in mixed aircraft fleets. Lighter aircraft primarily engage with the softer layers of compressible foam near the surface, while heavier aircraft penetrate deeper and engage with the harder layers of foam near the bottom. The report describes modeling and simulation results that showed improved mixed fleet performance compared to EMAS with a single material strength throughout the thickness.

[0010] The variable-depth concept was first proposed in ACRP Report 29 as consisting of multiple layers or tiers of compressible foam bonded together to complete the thickness of the EMAS bed. The bottom layer of the block has the highest density and crush strength, while the top layer has the lowest density and crush strength. The variable-depth nature of the bed provides improved mixed fleet stopping performance by allowing lighter aircraft to engage the softer upper layers, while heavier aircraft penetrate deeper and engage the harder lower layers of material.

[0011] From US2012 / 5247298, macropatterned materials and their use in connection with vehicle arresting systems are known. Particular embodiments provide 3D folded materials, honeycombs, lattice structures, and other periodic cellular material structures that can be used to stop vehicles. The materials can be designed to have properties that allow them to fracture reliably and predictably under pressure from the vehicle. The materials can be formed into various shapes and combined in various ways to provide the desired properties.

[0012] An aircraft overrun is an emergency situation in which one or more things go wrong. When an overrun occurs, the aircraft often does not exit along the runway centerline; instead, it may be offset to the left or right. The aircraft may also not travel in a direction parallel to the runway, but instead turn along the diagonal of its travel. Furthermore, typical runway designs include shallow side slopes to facilitate drainage, which can increase turning behavior in some situations. When an aircraft turns diagonally, it may take a shorter path through the EMAS arrestor bed. This results in premature exit along the side edge of the bed, thereby shortening the length of travel through the bed and reducing the protection the EMAS is designed to provide. EMAS currently does not have design features to control the aircraft's travel path, and innovations that can provide a centering effect are desirable.

[0013] Object of the invention The primary objective of the present invention is to provide an Advanced Material Arresting System (EMAS) bed for slowing and steering vehicles / aircraft that cannot stop under their own power. Summary of the Invention

[0014] The arrester bed is a bed of compressible foam material placed on a spread of ground or pressed into the ground, for example, like a basin filled with compressible foam material. In some embodiments, the arrester bed is placed at the end of a runway, but may be placed / applied anywhere it may be expected that a vehicle / aircraft will (unintentionally) require external assistance to make a controlled stop.

[0015] Arrester beds are typically made from an aggregate of granular compressible material that fills a basin placed on or in the soil / basement, or from prefabricated blocks of compressible material that are assembled on-site to form a bed on top of the soil / basement. The present invention relates to the latter arrester beds made by assembling and gluing prefabricated blocks. The adhesion of the prefabricated blocks to each other can be achieved, for example, by gluing, caulking, adhesive tape, etc.

[0016] The present invention is based on the recognition that the observed weakness of the joints between the prefabricated blocks, which typically have a lower shear strength than the continuous region of the prefabricated blocks, can be exploited to impart a directional load to the arrester bed that helps to center the path of travel of a vehicle passing through the arrester bed. That is, instead of arranging the prefabricated blocks in the typical orthogonal grid of the prior art, by orienting the prefabricated blocks at an angle, the retarding forces exerted on the vehicle wheels have a lateral component that provides an effect of assisting the vehicle to move along the central longitudinal axis of the arrester bed.

[0017] Thus, in a first aspect, the present invention relates to a vehicle arresting system comprising an arrester bed placed on a base / ground and having a longitudinal central axis extending from a front end to a rear end opposite the front end, the arrester bed comprising a plurality of prefabricated blocks of compressible foam material assembled and bonded together, the assembly of the prefabricated blocks comprising a set of an even number of straight lanes 11 of prefabricated blocks 10, half of the set being positioned on the left side of the longitudinal central axis of the arrester bed and half of the set being positioned on the right side. Each straight lane 11 of the prefabricated blocks 10 is inclined at an angle a towards the longitudinal central axis of the arrester bed 1, where 0° < a ≤ 30°, and when viewed from above, the set of straight lanes 11 forms a series of continuous inverted V patterns along the longitudinal central axis of the arrester bed, and the prefabricated blocks 10 are shaped and dimensioned such that they completely cover / fit exactly the surface area of the base / ground on which the arrester bed is placed.

[0018] As used herein, the term "longitudinal" refers to the direction in which a vehicle / aircraft entering the arrester bed is expected to move across the arrester bed. As used herein, the term "front end" is the side where a vehicle / aircraft is expected to enter the arrester bed / EMAS, and the "rear side" is the side opposite the front end. The arrester bed may, in some embodiments, be shaped as a longitudinally rectangular bed (when viewed from above), i.e., having a relatively short width compared to its diagonal length.

[0019] The term "arrestor bed" as used herein refers to a bed of compressible foam material placed on a spread of ground or pressed into the ground, for example, like a basin filled with compressible foam material. In some embodiments, the arrestor bed is placed at the end of a runway, but may be placed / applied anywhere where it may be expected that a vehicle / aircraft will (unintentionally) require external assistance to make a controlled stop. However, although the arrestor bed will be described below in relation to the need to avoid airfield and aircraft overrun accidents, the arrestor bed according to the present invention is not limited to aircraft / airfields and may be applied to absorb kinetic energy, allowing any wheeled vehicle crossing the arrestor bed to stop at any position whenever such functionality is desired. Arrestor beds are also referred to in the literature as "functional material arresting systems (EMAS)." These terms are used interchangeably herein.

[0020] The present invention according to the first aspect is not bound by any particular design, size, or location, but encompasses any size and design of arrester bed known or conceivable to those skilled in the art. Furthermore, the present invention is not dependent on how the arrester bed is made and assembled. Any known and conceivable method of forming a bed of prefabricated blocks of compressible foam material in the location where the arrester bed will be located is encompassed by the present invention, so long as the arrester bed has inclined straight lines of prefabricated blocks that form a continuous series of inverted V-shaped patterns along the longitudinal center axis relative to the direction from the front end to the rear end of the arrester bed.

[0021] As used herein, the term "compressible foam material" encompasses any material known to those skilled in the art to be suitable as a deformable / foldable material that engages the oncoming wheels of a vehicle / aircraft and absorbs kinetic energy from the vehicle / aircraft, bringing the vehicle / aircraft to a controlled stop. Examples of suitable materials include, but are not limited to, cellular cement, cellular cement-based materials, foamed cement, polymer foam, honeycomb, metal honeycomb, vermiculite, perlite, ceramic foam, foam glass, and other isotropic or anisotropic compressible / deformable materials, or combinations thereof.

[0022] When a compressible foam material is subjected to a stress load, the foam material reaches a certain plateau value, σ, where the foam material begins to fracture / compress. u , the stress load is maintained. The foam material is gradually compressed during the plateau stress until all or nearly all of the voids in the foam microstructure collapse. At this point, the material has significantly stiffened, and further compression requires dramatically higher stress / compression forces. A typical compressive stress-strain curve for a compressible foam material is shown in Figure 2. The degree of compression at the end of the plateau is determined by the maximum compressive strain, ε, of the material. max , and is important in determining the overall energy absorption potential of a compressible foam material because energy absorption is related to the area under the stress-strain curve. Larger maximum compressive strain values ​​correspond to a longer plateau region in the load curve and higher energy absorption. As used herein, the term "compressive strength" refers to the plateau value, σ, as determined by ASTM CI165-07(2017), unless otherwise specified. u , refers to.

[0023] The compressible foam material of the arrester bed has a mechanical strength adjusted so that the arrester bed cannot support the wheels of a vehicle / aircraft entering the arrester bed, but sinks a distance within the compressible foam material so that the compressible foam absorbs kinetic energy from the vehicle / aircraft and forces the vehicle / aircraft to a stop, as shown in the photograph in Figure 1. The compressive strength of the compressible foam material that provides an effective yet controlled stopping action against a vehicle / aircraft depends largely on the expected tire pressure that will be exerted on the surface of the arrester bed by the wheels of the vehicle / aircraft entering the arrester bed. Because the mass of a vehicle / aircraft can vary widely, the range of compressive strengths that provide effective stopping action also varies widely. Therefore, it is necessary to adapt the compressive strength of the compressible foam material of the arrester bed depending on the vehicle / aircraft intended to be stopped by it. However, determining the required compressive strength is within the ordinary skill of one skilled in the art and may be performed by experimental material testing and / or numerical modeling, as described in ACRP Report 29 [1] (see, for example, Chapters 8 and 9). In practice, for vehicle arresting system applications at passenger airfields, the compressive strength of the compressible foam material may advantageously range from 6.9 to 689.8 kPa (1 to 100 psi), preferably from 68.9 to 620.5 kPa (10 to 90 psi), more preferably from 137.9 to 551.8 kPa (20 to 80 psi), more preferably from 206.8 to 482.6 kPa (30 to 70 psi), and most preferably from 275.8 to 413.7 kPa (40 to 60 psi).

[0024] In some embodiments, each prefabricated block may be made from multiple smaller blocks 7 glued together in a vertical stack, for example by gluing. This gives the prefabricated block a layered, layered structure. This method of assembling prefabricated blocks into an arrester bed is sometimes called the block method. An example of such an assembly for making an EMAS is shown schematically in FIG. 4a). The figure shows a schematic diagram of an arrester bed 1 made up of multiple rows 2, each row consisting of several prefabricated blocks 10 of compressible energy-absorbing material arranged side by side. As can be seen from the detailed enlargement, each prefabricated block 10 of the bulk portion of the arrester bed is made up of multiple layers 9 of smaller blocks 7, here four, stacked and glued together. In this embodiment, tapering at the front and / or sides of the arrester bed may be achieved simply by applying fewer smaller blocks in the stack for the first row of the arrester bed and / or at the ends of each row.

[0025] In some embodiments, the block may have a layered structure, where each layer is made of smaller blocks 8, and the smaller blocks 8 are offset relative to the layer below it, forming a brick pattern as shown in FIG. 4b. That is, the prefabricated block comprises a vertical stack of multiple layered layers 9 bonded together, where each layer 9 is made of a second multiple of smaller blocks 8 arranged in a single horizontal plane, and the smaller blocks 8 of one layer 9 are offset relative to the multiple smaller blocks 8 of the layered layer 9 below and / or above it, from bottom to top, so that the smaller blocks 8 of the prefabricated block form a brick pattern. Such a structure results in an arrester bed with more monolithic mechanical properties.

[0026] In some embodiments, the arrester bed may be provided with a cover layer over the compactible energy absorbing material to protect it from the environment, jet blast, etc. The present invention may apply any known conceivable cover layer known to those skilled in the art as suitable for an arrester bed made of foam / compressible energy absorbing material. Examples of suitable cover layers include a thin plastic top, a cement board top, a polymer coating or sealant, paint, or a combination thereof. The exemplary embodiment shown in Figures 4a) and 4b) includes a cover layer 5.

[0027] In some embodiments, the arrester bed may have a depth variation in compressive strength, where the compressive strength increases as the bed depth increases. This provides the arrester bed with improved performance in mixed vehicle / aircraft situations, as the wheels of lighter vehicles only engage the softer upper layers, while the wheels of heavier vehicles / aircraft engage deeper into the arrester bed, as shown schematically in Figures 3a and 3b. In embodiments in which the prefabricated block 10 has a layered structure, the depth variation in compressive strength can be achieved by simply gluing together smaller blocks 7, 8 with progressively stronger compressive strengths at lower depths, with the bottom layer having the highest compressive strength and the top layer having the weakest, with each successive layer having a weaker compressive strength than the smaller block below it. An example of such an embodiment is shown in Figures 3a and 3b.

[0028] In an exemplary embodiment having a layered structure with depth-varying compressive strength, the upper layers produce a softer material response under vehicle / aircraft tire load than the solid compressible energy-absorbing material, thereby acting similarly to a lower density compressible energy-absorbing material with lower compressive strength. The lower layers produce a stiffer material response under aircraft tire load, and in the limit, the strength approaches that of the solid compressible energy-absorbing material. The bottom layer may be a continuous compressible energy-absorbing material with no voids. In an exemplary embodiment, one or a second plurality of smaller blocks 7, 8 in the top layer 9 of the layered prefabricated block 10 has a first compressive strength, one or a second plurality of smaller blocks 7, 8 in the first layered layer 9 below the top layer has a second compressive strength, one or a second plurality of smaller blocks 7, 8 in the second layered layer 9 below the top layer has a third compressive strength, and so on down to the bottom layer 9, where the first compressive strength < the second compressive strength < the third compressive strength, and so on down to the bottom layer 9.

[0029] It is clear from the context that the angle α relative to the longitudinal central axis of the arrester bed is an angle formed in the horizontal plane such that the inclination of the linear lane produces a lateral force on a vertically oriented wheel moving longitudinally through the arrester bed. Therefore, as used herein, the term "angle α" refers to the angle at which the linear lane of the prefabricated blocks inclines in the horizontal plane toward the longitudinal central axis of the arrester bed in the direction of travel, as shown diagrammatically in FIG. 5. The figure illustrates an exemplary embodiment of an arrester bed 1 assembled from prefabricated blocks 10 arranged in a set of linear lanes or rows, indicated in the figure by their longitudinal sides 21. The figure also indicates one line 11 of the prefabricated blocks 10 with a rectangular staple marked with reference numeral 11, and the direction of one row 2 with a rectangular staple marked with reference numeral 2. The arrester bed has a front end that enters the arrester bed in the direction of travel indicated by the two staple arrows, along which the vehicle / aircraft to be stopped arrives. As can be seen in the figure, the slope of the straight lanes is such that they slope from either side of the axis toward the central longitudinal axis indicated by the staple line marked A-A'.

[0030] In some embodiments, the set of straight lines of the prefabricated block may be inclined at an angle α, where 0°<α≦28°, preferably 1°≦α≦25°, more preferably 2°≦α≦23°, more preferably 3°≦α≦20°, more preferably 4°≦α≦15°, more preferably 5°≦α≦15°, and most preferably 5°≦α≦10°, toward the central longitudinal axis of the bed that forms an inverted V pattern relative to the direction from the front end to the rear end of the arrester bed.

[0031] In some embodiments, the prefabricated blocks may be shaped to interlock with one another when assembled to facilitate assembly at the runway construction site. The prefabricated blocks may feature interlocking geometric features on their edges. The interlocking features may be designed to interlock vertically, for example, with a tongue-and-groove interlocking mechanism as shown in FIG. 6a, or horizontally, for example, with complementary male and female jigsaw puzzle-like geometric structures as shown in FIG. 6b. FIG. 6a) schematically illustrates a single prefabricated block and an assembly of three blocks. When viewed from the side, the blocks have a groove-type geometric structure 21 and an opposite tongue-type geometric structure 22, such that when assembled in a line, the groove of one block interlocks with the tongue of the next block in the lane. Similarly, as can be seen in FIG. 6b), FIG. 6b) illustrates a single prefabricated block 10 and an assembly of four blocks when viewed from above, with the prefabricated block 10 having two male geometric structures 23 and two female geometric structures 24 that interlock with one another when assembled. Linkages may be designed with linkage tolerances ranging from one millimeter to several centimeters to accommodate thermal expansion of a large bed of many linked blocks. Linkages also provide a smoother stopping force for the aircraft by eliminating gaps between blocks, which can create a vibrating speed bump effect on the aircraft tires during arrestment.

[0032] In some embodiments, a block with a depth variation may have layered layers oriented with inclinations toward the centerline of the arrester bed. That is, by having the layered layers 9 of the prefabricated block 10 inclined so that the layered layers 9 are substantially parallel (i.e., horizontal) to the longitudinal central axis of the arrester bed and inclined so that they slope laterally downward toward the longitudinal central axis of the arrester bed, the layered layers are inclined so that they slope downward toward the centerline. Figure 7a) is a perspective view from the side and top of a single block 10 having six layers 9 of compressible energy-absorbing material with gradually weakened compressive strength toward the top. As can be seen, each layer is inclined somewhat toward the centerline, indicated by the staple lines marked A and A'. Figure 7b) illustrates the same block as Figure 7a), but now viewed from the front surface. A wheel 12 entering the block 10 and traveling longitudinally comes into contact with a relatively large amount of weak compressible energy-absorbing material on its right side (relative to the direction of travel) and is therefore subjected to a lateral force towards the centreline, as shown by the black arrow in the figure.

[0033] An exemplary embodiment of an arrester bed assembled with blocks having layered layers of varying depth and slope is shown in FIG. 8. In this exemplary embodiment, the arrester bed 1 includes eight blocks with layered layers of varying depth and slope in each row (horizontally): four blocks 10 on the left side of the centerline A-A' and four blocks 13 on the right side. The slope of the layers in the blocks 10 on the left side of the centerline slopes the layered layers downward toward their right side, while the slope of the layers in the blocks 13 on the right side of the centerline slopes the layered layers downward toward their left side. As shown in this example, an aircraft approaching the arrester bed off-line, for example, on the left side of the arrester bed, experiences a lateral force that tends to guide the aircraft into alignment on the centerline. This effect is in addition to the orientation effect of the set of linear stripes / zones having a compressive strength lower than the bulk compressive strength according to the present invention.

[0034] In some embodiments, the prefabricated block may include one or more linear through-voids, channels, or holes aligned perpendicularly on the lateral sides of the block such that the through-voids, channels, or holes of successive blocks in each linear lane align and form through-voids, channels, or holes extending throughout the entire linear lane of the block. These through-voids, channels, or holes in the linear lanes form linear zones in the arrester bed that have a compressive strength lower than the bulk compressive strength of the arrester bed and are oriented toward the central axis at the same angle as the inclination angle of the linear lanes of the block, thereby enhancing a centering effect that helps vehicles / aircraft pass through the arrester bed parallel to and along the longitudinal central axis of the arrester bed formed by the relatively weak bonds along the side walls of the prefabricated block. [Brief explanation of the drawings]

[0035] [Figure 1] Figure 1 is reproduced from Wikipedia https: / / en.wikipedia.org / wiki / Engineered_materials_arrestor_system showing a photograph of an aircraft wheel entering the EMAS bed and being arrested. [Figure 2] FIG. 2 shows a typical compressive stress-strain curve for a compressible foam material. [Figure 3a)] FIG. 3a) is a diagram illustrating the penetration depth of a heavy wheel (FIG. 3a)) entering an arrester bed having a layered structure of multiple layers of compressible foam material, with the upper layers having a lower compressive strength and the lower layers having a higher compressive strength of the compressible foam material. [Figure 3b)] Figure 3b) A schematic illustration of the penetration depth of a heavy wheel (Figure 3b) penetrating an arrestor bed having a layered structure of multiple layers of compressible foam material, with the upper layers having a lower compressive strength and the lower layers having a higher compressive strength of compressible foam material. [Figure 4a)] FIG. 4a is a diagram illustrating a schematic diagram of an exemplary embodiment of a block-type arrester bed. [Figure 4b)] FIG. 4b is a diagram illustrating a schematic diagram of an exemplary embodiment of a monolith-type arrester bed. [Figure 5] FIG. 5 is a diagram illustrating a top view of an exemplary embodiment of an arrester bed according to the present invention with angled lanes of prefabricated blocks. [Figure 6a)] FIG. 6a) is a diagram illustrating an exemplary embodiment of a building block with interlocking geometric shapes. [Figure 6b] FIG. 6b) is a diagram illustrating an exemplary embodiment of a building block with interlocking geometric shapes. [Figure 7a)] FIG. 7a) is a diagram illustrating an exemplary embodiment of a building block having a layered structure with varying depths and sloping layers. [Figure 7b] FIG. 7b) is a diagram illustrating an exemplary embodiment of a building block having a layered structure with varying depths and sloping layers. [Figure 8] FIG. 8 is a diagram illustrating an arrester bed assembled from the blocks shown in FIGS. 7a) and 7b). [Figure 9] Figure 9 shows the calculated lateral forces on a B737 main gear entering a tilted bed of foam glass at different tilt angles. DETAILED DESCRIPTION OF THE INVENTION

[0036] The invention is explained in more detail by means of an exemplary embodiment of an arrester bed intended to stop an aircraft entering the bed.

[0037] The exemplary embodiment of the arrester bed is constructed from prefabricated blocks of foam glass having a compressive strength of 344.7 kPa (50 psi) assembled to form linear lanes of prefabricated blocks angled 15° toward the central longitudinal axis of the arrester bed, forming a pattern similar to the exemplary embodiment illustrated in FIG.

[0038] The dimensions of the prefabricated blocks in the bulk section of the straight line were 2.13 m in length and width, and 76 cm in height. The prefabricated blocks located at the edge of the arrester bed, and adjacent blocks on both the left and right sides of the longitudinal axis, were shaped to create a continuous rectangular arrester bed 49 m wide and 98 m long. The arrester bed thus covered a surface area equivalent to that of a small football field.

[0039] The longitudinal sides between adjacent straight lanes of the arrester bed blocks form a set of angled zones of relatively weak compressive strength compared to the compressive strength of the blocks, which generates a directional central force. In automobiles, this type of force is observed by the rutting of the road surface, which in that context is called tramway.

[0040] The effective horizontal load of crushable foam on an aircraft tire depends on the inclination angle of the tire relative to the channel or lane of material. The resultant lateral and longitudinal forces (F x and F y ) can be calculated by integrating the component forces around the circumference of the tire in contact with the crushable foam. As the tire's path of travel becomes more perpendicular to the foam layer interface, the average lateral force decreases toward zero. Similarly, once the tire completely passes the boundary of the crushable foam layer, the lateral forces balance and the net force decreases toward zero.

[0041] As an example, the lateral forces on the main gear tires of a Boeing 737 entering a straight lane of blocks at different angles were calculated for several inclination angles: 15, 30, 45, 60, and 75°, as shown in Figure 9. The main gear of a Boeing 737, rated at 199 kN (44,700 lbf), has a radius of 113 cm (44.5 in) and a width of 42 cm (16.5 in). The scenario was simplified to include a single exposed surface of crushable foam adjacent to a void. The directional load was calculated by integrating along the arc length of the tire in contact with the crushable foam. This calculation was performed at a series of positions as the tire gradually entered the crushable foam by moving in the direction of travel.

[0042] As can be seen in Figure 9, the lateral forces in this example reach their highest magnitude and are maintained over the longest travel length at a shallow 15 degree tilt angle. As the material becomes more perpendicular to the direction of travel at tilt angles greater than 45 degrees, the lateral loads become weaker and shorter.

[0043] If the tire engages the foam material at a 15-degree tilt angle and the effective engagement depth is two-thirds of the turning radius, or 2 / 3 x 18.5 inches = 12.4 inches (31.5 cm), referring to the 15-degree curve in Figure 9, the peak lateral force is 0.42 kip per inch of material depth or 420 lbf (735 N / cm). Therefore, the total lateral force is Fx = 420 lbf / in x 12.4 in = 5,200 lbf (23.1 kN). Dividing this peak load by the tire's rated normal load gives 5,200 lbf / 44,700 lbf = 11.6%. This level of load is significant and acts on all aircraft tires, resulting in an effective central force on the aircraft of approximately 11.6% of the aircraft's weight. As shown by the plot, this load rises and falls over a long travel distance of approximately 60 inches (152 cm).

[0044] References 1. Matt Barsotti et al. (2009), “ACRP Report 29: Developing Improved Civil Aircraft Arresting Systems” US Transportation Research Board, DOI:10.17226 / 14340 The inventions described in the original claims of this application are set forth below. [1] A vehicle arresting system comprising an arrester bed (1) resting on a base / ground and having a longitudinal central axis extending from a front end to a rear end opposite said front end, said arrester bed (1) comprising a plurality of prefabricated blocks (10) of compressible foam material assembled and bonded side by side, said assembly of prefabricated blocks comprising a set of an even number of linear lanes (11) of prefabricated blocks (10), half of said sets being positioned to the left of said longitudinal central axis of said arrester bed and half of said sets being positioned to the right; A vehicle arresting system, characterized in that each straight line (11) of the prefabricated block (10) is inclined at an angle α toward the longitudinal central axis of the arrester bed, where 0°<α≦30°, and when viewed from above, the set of straight lanes (11) form a series of continuous inverted V-patterns along the longitudinal central axis of the arrester bed, and the prefabricated blocks (10) are shaped and sized so that they completely cover / fit the surface area of ​​the base / ground on which the arrester bed is placed. [2] The vehicle arresting system of [1], wherein the set of relatively low compressive strength straight lines is inclined at an angle α, where 0°<α≦28°, preferably 1°≦α≦25°, more preferably 2°≦α≦23°, more preferably 3°≦α≦20°, more preferably 4°≦α≦15°, more preferably 5°≦α≦15°, and most preferably 5°≦α≦10°. [3] The vehicle arresting system of [1] or [2], wherein the compressible foam material is a material selected from cellular cement, cellular cement material, foamed cement, polymer foam, honeycomb, metal honeycomb, vermiculite, perlite, ceramic, foam glass, and other isotropic or anisotropic compressible / deformable materials, or combinations thereof. [4] The vehicle arresting system according to any one of [1] to [3], wherein the compressible foam material has a compressive strength in the range of 6.9 to 689.8 kPa (1 to 100 psi), preferably 68.9 to 620.5 kPa (10 to 90 psi), more preferably 137.9 to 551.8 kPa (20 to 80 psi), more preferably 206.8 to 482.6 kPa (30 to 70 psi), and most preferably 275.8 to 413.7 kPa (40 to 60 psi). [5] The vehicle arresting system of any one of [1] to [4], wherein the arrester bed has a depth variation of compressive strength that increases with increasing bed depth, obtained by providing the arrester bed with a layered structure of multiple layers of compressible foam material having a higher compressive strength for each successive layer of compressible foam material up to the bottom layer of the arrester bed. [6] The vehicle arresting system according to any one of [1] to [5], wherein the prefabricated blocks are bonded together by gluing, caulking, or adhesive tape. [7] The assembly block (10) is a vertical stack of layered layers (9) glued together, each layer (9) consisting of one smaller block (7); or 10. A vehicle arresting system according to any one of claims [1] to [6], comprising a vertical stack of a plurality of layered layers (9) bonded together, each layered layer (9) consisting of a second plurality of smaller blocks (8) arranged in a single horizontal plane, the smaller blocks (8) of a layered layer (9) being offset from lower to upper layer relative to the plurality of smaller blocks (8) of the layered layer (9) below and / or above it, such that the smaller blocks (8) of the prefabricated block (10) form a brick pattern. [8] The vehicle arresting system of [7], wherein the one or the second plurality of smaller blocks (7, 8) in the upper layer (9) of the layered assembly block (10) have a first compressive strength, the one or the second plurality of smaller blocks (7, 8) in the first layered layer (9) below the upper layer have a second compressive strength, and the one or the second plurality of smaller blocks (7, 8) in the second layered layer (9) below the upper layer have a third compressive strength, and so on up to the lower layered layer (9), where the first compressive strength < the second compressive strength < the third compressive strength, and so on up to the lower layered layer (9). [9] The vehicle arresting system described in [8], wherein the layered layer (9) of the prefabricated block (10) is inclined so that the layered layer (9) is substantially parallel to the longitudinal central axis of the arrester bed and slopes laterally downward toward the longitudinal central axis of the arrester bed.

[10] The vehicle arresting system according to any one of [1] to [9], wherein the prefabricated block (10) further comprises interconnecting geometric features at its edges.

[11] The vehicle arresting system of any one of [1] to

[10] , wherein the prefabricated block (10) further comprises one or more linear through-voids, channels, or holes oriented perpendicular to the side of the block.

Claims

1. 1. A vehicle arresting system comprising an arrester bed (1) resting on a base / ground and having a longitudinal central axis extending from a front end to a rear end opposite the front end, the arrester bed (1) comprising a plurality of prefabricated blocks (10) of compressible foam material assembled and bonded side by side, the assembly of the prefabricated blocks comprising sets of an even number of linear lanes (11) of prefabricated blocks (10), half of the sets being positioned on the left side of the longitudinal central axis of the arrester bed and half of the sets being positioned on the right side; a vehicle arresting system, characterized in that each straight line (11) of the prefabricated block (10) is inclined at an angle α toward the longitudinal central axis of the arrester bed, where 0°<α≦30°, and when viewed from above, the set of straight lanes (11) form a series of continuous inverted V-patterns along the longitudinal central axis of the arrester bed, and the prefabricated blocks (10) are shaped and sized so that they completely cover / fit the surface area of ​​the base / ground on which the arrester bed is placed.

2. 2. The vehicle arresting system of claim 1, wherein the set of relatively low compressive strength straight lines are inclined at an angle α, where 0°<α≦28°.

3. 3. The vehicle arresting system of claim 1, wherein the compressible foam material is a material selected from cellular cement, cellular cement material, foamed cement, polymer foam, honeycomb, metal honeycomb, vermiculite, perlite, ceramic, foam glass, and other isotropic or anisotropic compressible / deformable materials, or combinations thereof.

4. 3. The vehicle arresting system of claim 1 or 2, wherein the compressible foam material has a compressive strength in the range of 6.9 to 689.8 kPa (1 to 100 psi).

5. 3. The vehicle arresting system of claim 1, wherein the arrester bed has a depth variation in compressive strength that increases with increasing bed depth, achieved by providing the arrester bed with a layered structure of multiple layers of compressible foam material having a higher compressive strength for each successive layer of compressible foam material up to a bottom layer of the arrester bed.

6. 3. The vehicle arresting system of claim 1 or 2, wherein the prefabricated blocks are adhered together by glue, caulking, or adhesive tape.

7. The assembly block (10) is a vertical stack of layered layers (9) glued together, each layer (9) consisting of one smaller block (7), or 3. The vehicle arresting system of claim 1, comprising a vertical stack of layered layers (9) bonded together, each layer (9) consisting of a second plurality of smaller blocks (8) arranged in a single horizontal plane, the smaller blocks (8) of a layered layer (9) being offset from lower to upper layer relative to the plurality of smaller blocks (8) of the layered layer (9) below and / or above it, such that the smaller blocks (8) of the prefabricated block (10) form a brick pattern.

8. 8. The vehicle arresting system of claim 7, wherein the one or the second plurality of smaller blocks (7, 8) in the upper layer (9) of the layered prefabricated blocks (10) have a first compressive strength, the one or the second plurality of smaller blocks (7, 8) in a first layered layer (9) below the upper layer have a second compressive strength, and the one or the second plurality of smaller blocks (7, 8) in a second layered layer (9) below the upper layer have a third compressive strength, and so on down to the lower layer (9), where the first compressive strength < the second compressive strength < the third compressive strength, and so on down to the lower layer (9).

9. 9. The vehicle arresting system of claim 8, wherein the layered layers (9) of the prefabricated block (10) are inclined such that the layered layers (9) are substantially parallel to a longitudinal central axis of the longitudinal direction and are inclined laterally downward toward the longitudinal central axis of the arrester bed.

10. 3. The vehicle arresting system of claim 1 or 2, wherein the prefabricated block (10) further comprises interconnecting geometric features at its edges.

11. 3. The vehicle arresting system of claim 1 or 2, wherein the prefabricated block (10) further comprises one or more linear through-voids, channels, or holes oriented perpendicular to a side of the block.

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