Crash impact attenuator system and method

Abstract

A crash impact attenuator system for deployment in front of a structure includes a track and a plurality of baffles initially arranged in a spaced relationship along the length of the track. Each of the plurality of baffles moves along the track such that when the front end of the crash attenuator system is subjected to an impact force from a vehicle, a first baffle moves rearwardly along the track and strikes a second baffle, whereupon both the first and second baffles move further rearwardly along the track, and this process continues with additional baffles until the impact force is fully attenuated. A tear-off member on the crash attenuator system engages material forming a side or fender panel of the crash attenuator system to attenuate the impact force.

Description

Background Art

[0001] The present invention relates generally to crash impact attenuators and, more particularly, to motor vehicle and highway guardrail crash impact attenuators including securing systems for protecting the leading edges of abutments and other fixed roadside hazards.

[0002] Vehicle accidents on highways are a major worldwide problem and are undoubtedly one of the greatest causes of economic and human loss and suffering in developed countries today. In particular, to mitigate the loss of life resulting from these tragic accidents, guardrails, crash buffers, vehicle-mounted crash attenuators, crash barrels, etc. have been developed to attenuate the impact of vehicles with rigid, immovable obstacles, such as bridge abutments.

[0003] These types of crash attenuators must absorb the impact energy of a vehicle without exceeding the limits of the vehicle's deceleration. In addition, it must be suitable for both heavy and light vehicles. The lightest vehicles experience lower decelerations, which will determine the limits of the maximum force generated by the shock absorber and the heavy vehicle, thereby determining the total impact deformation required. This force cannot exceed the limits of the light vehicle, so the initial force and deceleration are lower, limiting the energy absorption. Increasing the impact resistance as the vehicle "falls" from impact velocity to zero is a very important feature of a crash attenuator system that meets strict government safety standards. When the side is hit obliquely, the crash cushion is used to redirect the vehicle back to the road and prevent severe impact with a rigid point hazard. A typical crash cushion includes side rails / plates, a center partition, a track assembly for anchoring and guiding the center partition, and an energy absorber. As crash safety standards have evolved to higher and higher requirements to better protect vehicle occupants from injury, it has become clear that a new generation of crash impact attenuators or crash cushions are needed to perform this function and meet these high standards in an innovative, inexpensive, very simple but effective way. The present invention meets and exceeds these high standards.

[0004] The present invention and additional features and advantages thereof may be best understood by referring to the following description taken in conjunction with the accompanying drawings. Summary of the invention

[0005] The present invention is particularly innovative because the side panels disposed thereon also serve as energy absorbers, thereby eliminating the need for additional internal absorber components. This reduction in system complexity and cost has not been used in previous crash mitigation technologies.

[0006] The side panels of the new crash impact attenuator system are designed to slide or telescope over each other as the ends of the crash attenuator system compress. This is a common feature of crash pads. However, the attachment bolts at the downstream end of each panel are designed to tear the side panel / track as the panel moves past the attachment bolts. This tearing action absorbs energy as the system compresses and brings the errant vehicle to a controlled, safe stop before impacting the rigid hazard point. The resistance in the panels is controlled to absorb energy at a specified rate as the attenuator compresses. The resistance is initially designed to be low but increases with the overall length of the system. The forces can vary between panels and even within individual panel segments. The variation in resistance is achieved through several novel concepts, such as varying the thickness of the panels and introducing holes configured with various shapes that are cut into the panels along the tear path. Utilizing different shapes and spacing between shapes not only affects the resistance, but also helps control the consistency of the tear path and can be used to achieve different fracture modes (e.g., Mode 1 – tensile failure, Mode II – shear failure, Mode III – out-of-plane shear, or a combination of these failure mechanisms). In addition, some hole shapes can be used to reduce debris. Perforations can also be used to control resistance and tear paths. For plates with higher resistance, the holes or cutouts can be staggered to mitigate force peaks during impact events. The plates can then be configured for multiple forces and multiple impact conditions.

[0007] The structure of an exemplary embodiment of the crash cushion has a dual track design with two T-shaped tracks that anchor and guide the center partition. The tracks are welded to a base plate fixed to the sidewalk intermittently. The center partition and impact head are assembled from structural steel tubes and are equipped with feet that slide along the tracks. The feet on the impact head are elongated to prevent / limit the rotation of the impact head about the vertical and lateral axes respectively during eccentric / angle impacts and high bumper impacts on the front end of the device. The center partition feet are also designed to limit rotation. Both the impact head and the center partition are designed with sufficient lateral strength capacity to withstand the impact of the vehicle on one side of the crash cushion. The connecting bolts between the plate and the center partition / impact head are configured with specially designed, integral gasket plates to allow the plates to slide against each other, guide the tear path of the plates, and prevent the connecting bolts from pulling out of the side plate. In addition, the crash cushion is equipped with a crushable energy absorbing nose box, which can prolong the momentum transfer and extend the inertial pulse when the impact head and side plate begin to move at the beginning of the impact event. This feature reduces the force peaks applied to the vehicle and its occupants.

[0008] More specifically, in one aspect of the present invention, a collision impact attenuator system for mitigating direct vehicle impact with a structure is provided, comprising an attenuator portion, the attenuator portion comprising a plurality of support members. The fixed structure may include, for example, a concrete abutment, a guardrail system, a terminal and guardrail end treatment, etc. For example, in the case of a guardrail, the support member may simply be a support column. The attenuator system also includes a side panel, the side panel including one of a plurality of side panels disposed along a side of the attenuator portion, the side panel being adapted to slide rearwardly along the attenuator portion when the collision impact attenuator system is impacted by a vehicle, such that when the side panel slides rearwardly in response to the vehicle impact, the side panel slides on an adjacent second side panel of the plurality of side panels. Each of the plurality of side panels includes a plurality of holes disposed in the material constituting the individual side panel, the plurality of holes extending along the length of each of the plurality of side panels and being longitudinally spaced apart from each other.

[0009] Advantageously, a tearing member is provided on the attenuator portion, the tearing member being adapted to engage one of the plurality of holes in the side panel material. Thus, when the crash attenuator is struck by a vehicle, relative movement occurs between the side panel and the tearing member, thereby tearing a crack or slit in the material forming the side panel, which extends between adjacent holes of the plurality of holes. Such tearing of the side panel material attenuates the impact force. The side panel material is adjusted to optimize the tearing of the side panel material, the adjustment of the side panel material being accomplished by sizing and arranging the plurality of holes in a predetermined manner.

[0010] In the illustrated embodiment of the invention, the attenuator portion further comprises a track extending along the length of the crash attenuator system. In such an embodiment, the plurality of support members may include a plurality of baffles arranged in a spaced relationship along the length of the track, each of the plurality of baffles having a bottom end or foot adapted to movably engage the track so that when the crash impact attenuator system receives an impact force from an impacting vehicle, a first of the plurality of baffles moves rearwardly along the track and strikes a second of the plurality of baffles, wherein the first and second of the plurality of baffles move further rearwardly along the track, the process continuing with the attachment of additional baffles of the plurality of baffles until the impact force is fully attenuated. In the illustrated embodiment, the side panels are also referred to as fenders, which is typically the case for construction of crash cushions of the type shown and described.

[0011] In the illustrated embodiment, the tear-off member comprises a bolt and is disposed on one of the plurality of baffles. The tear-off member preferably comprises a plurality of tear-off members to obtain a greater attenuation effect.

[0012] Another advantageous feature of the present invention is the ability to adjust the side panels for optimal attenuation. For example, in some embodiments, the holes are not evenly spaced along the length of the side panels. Adjacent holes in the plurality of holes that are closer to the first end or rear end of the side panel (rightmost in the illustrated embodiment) can be more closely spaced than adjacent holes in the plurality of holes that are closer to the second end or front end (leftmost in the illustrated embodiment). The sizes of the plurality of holes can be different from each other. The last hole in the plurality of holes can be larger and more slender than those holes in the plurality of holes that are located near the front end of the side panel. The material forming the side panel can be thinner toward the rear end of the side panel and thicker toward the front end of the side panel. In some embodiments, the plurality of holes can be arranged to form a first row of holes and a second row of holes spaced from each other along the height of the side panel, and each hole in the first row of holes and each hole in the second row of holes on the side panel correspond to each other and are longitudinally aligned with each other. In other multi-row embodiments of this type, each hole in the first row of holes and each hole in the second row of holes on the side panel correspond to each other and are longitudinally staggered with each other.

[0013] In the illustrated embodiment, the side panel includes a first section attenuator portion and the second side panel includes a second section attenuator portion, the first section attenuator portion is in front of the second section attenuator portion, and the side panel is in the front section and is more flexible than the second side panel, and the second side panel is in the rear section and is located behind the front section. The side panel is adjusted to be more flexible than the second side panel due to one or more of the following: a) the side panel has more holes than the second side panel, b) the average size of the holes in the second side panel is smaller than the average size of the holes in the side panel, c) the shape of some or all of the holes in the side panel is different from the shape of some or all of the holes in the second side panel, d) the spacing of the holes in the second side panel is greater than the spacing of the holes in the side panel, and e) the average thickness of the side panel is less than the average thickness of the second side panel.

[0014] For example, the plurality of side panels may also include a third, fourth and fifth side panel extending longitudinally rearward of the second side panel, wherein the third side panel includes a third section attenuator portion, the fourth side panel includes a fourth section attenuator portion, and the fifth side panel includes a fifth section attenuator portion, wherein the third side panel is harder than the second side panel, the fourth side panel is harder than the third side panel, and the fifth side panel is harder than the fourth side panel. Thus, from the first section to the fifth section in sequence, each subsequent side panel may be adapted and constructed to be harder than the side panel of the previous section. It should be noted that in some embodiments, the same panel may be used for the subsequent sections, so in this case, each subsequent side panel is equal to or greater than the stiffness / resistance of the previous side panel in the rearward direction. Of course, a total of five sections are merely exemplary or illustrative, as any number of sections may be employed within the parameters of the present invention. In each of the aforementioned embodiments, the nose box is typically disposed at the very front end of the collision attenuator. By definition, a "soft" board or material will provide less resistance or less energy absorption per unit displacement, while a "hard" board or material will provide more resistance or more energy absorption per unit displacement than a soft board.

[0015] An advantageous feature of the present invention is that the bolt can be assembled with a bent washer plate. The bent washer plate includes a flared front wing. The limited front extension of the bent washer plate allows the side plate to curl and prevents pile-up when the side plate is torn by the bolt.

[0016] The plurality of holes extending along the length of each of the plurality of side panels and longitudinally spaced from each other may advantageously include a row of holes in each of the plurality of side panels, the row of holes extending longitudinally along each of the plurality of side panels terminating before reaching a front end in each of the plurality of side panels. The termination of the row of holes in each of the plurality of side panels facilitates the initiation of shearing of the next adjacent side panel in the plurality of side panels, thereby reducing a spike in impact force attenuation when the crash impact attenuator system is compressed.

[0017] Another advantageous feature of the present invention is that the track includes first and second tracks disposed parallel to each other and extending along the length of the attenuator section, each of the first and second tracks having a T-shaped configuration including a top flange disposed horizontally and extending along the length of each track. The bottom end or footing of each of the plurality of baffles includes a first bottom end or footing configured to wrap around the top flange of the first track and a second bottom end or footing configured to wrap around the top flange of the second track. This allows for the lateral load from an oblique impact to be distributed to each of the first track and the second track of the crash attenuator system.

[0018] In another aspect of the present invention, a crash attenuator system for deployment in front of a fixed structure is provided. The system includes a base including a first outer rail extending along the length of the base, a second outer rail spaced from the first outer rail and extending along the length of the base, and a plurality of spaced cross members or support tubes extending across the width of the base and connecting the first outer rail to the second outer rail. The system also includes an upper attenuator portion including a plurality of baffles initially arranged in a spaced relationship along the length of the base. Each of the plurality of baffles has a bottom end adapted to be movably engaged with each of the first outer rail and the second outer rail, such that when the front end of the upper attenuator portion receives an impact force from an errant vehicle, a first of the plurality of baffles moves rearwardly along the first and second outer rails and strikes a second of the plurality of baffles, causing both the first and second of the plurality of baffles to move further rearwardly along the first and second outer rails, and this process continues with additional use of other baffles of the plurality of baffles until the impact force is fully attenuated. The side plate is arranged on the upper attenuator part, and has a hole arranged therein, which is suitable for engaging the tearing member arranged on the upper attenuator part. When the impact force hits the collision attenuation system, the tearing member and the side plate can move relative to each other, so that the tearing member tears the side plate, thereby increasing the attenuation of the impact force.

[0019] In yet another aspect of the present invention, a method for attenuating a collision impact force applied by an errant vehicle that would otherwise strike an immobile object is provided. The method includes the steps of receiving an impact force at a front end of a collision impact attenuator having a base and an upper attenuator portion, causing one or more members of the upper attenuator portion to move rearwardly along the base in response to the impact force, causing a tearing member disposed on the collision impact attenuator to tear material constituting a side panel disposed on the collision impact attenuator when the one or more members of the upper attenuator portion move in response to the impact force, wherein the tearing of the side panel material serves to attenuate the impact force.

[0020] In some embodiments, the tearing member is a protrusion disposed on one of the one or more members of the upper attenuator portion that initially engages a hole formed in the side panel material. There are a plurality of holes in the side panel material that are longitudinally arranged in a spaced relationship, and the tearing step includes tearing the side panel material between the initially engaged hole and an adjacent hole in the plurality of holes to form a crack or slit in the side panel. As shown, the tearing member may include a bolt, or may include other components, such as a rod, a plate, a wedge, etc.

[0021] As mentioned above, the simplest embodiment of the present invention relates to forcing the tearing member to pass through the substrate with a continuous cross section and to rupture the substrate to dissipate energy. However, in order to control the fracture and the associated energy dissipation, various modifications can be made to the substrate cross section. Various shapes of holes can be cut out in the substrate cross section in the path of the tearing member. These shapes can be used to change the number of fracture modes, fracture surfaces, and help control the expansion of fractures or cracks. For example, a series of triangular incisions can be used to form a single mode I (tensile) fracture surface in the substrate. Or, a series of trapezoidal incisions can be used to form a combined fracture surface of mode II and mode III in the substrate. Having multiple fracture surfaces may produce debris from the substrate, while only a single fracture surface is produced along the path of the tearing member without producing debris. Other potential shapes that can be used include, but are not limited to, square, rhombus, rectangle, groove, circle, semicircle, crescent, etc.

[0022] Longitudinal multiple perforations of the substrate may also be used alone or in combination with formed holes in the substrate. Longitudinal multiple perforations change the forces and energy generated by the substrate fracture by removing a portion of the substrate portion. In addition, longitudinal multiple perforations may be used to control the propagation of the fracture surface. A single row may result in a single failure line, while multiple rows may help remove material.

[0023] Grooves, notches, or other stress concentrating features in the substrate that do not completely penetrate the cross section of the substrate may also be used alone or in combination with formed holes or perforations in the substrate. These features provide another mechanism for controlling the force and energy dissipation of the fracture of the material and can help control the propagation of the fracture through the substrate.

[0024] Various changes in the longitudinal spacing of the substrate cross section can also be used to control the fracture and energy dissipation of the present invention. These changes in longitudinal spacing can be used to control the fracture mode and increase or decrease the force level and energy dissipation by changing the amount of material that the tear member breaks.

[0025] If multiple tear members and fracture lines are used in a single cross section of the substrate, the pattern produced by a given combination of formed holes, perforations, grooves, scores, and longitudinal spacing can be staggered or offset in the machine direction so that the patterns are not synchronized with each other. Staggered patterns cause intermittent fractures along the tear path to occur at different times, thereby limiting high strength peaks and providing more consistent force levels.

[0026] A variety of the above changes to the substrate cross section can be used within a single substrate section to produce the desired energy dissipation. In addition, the modification pattern can be changed along the length of the substrate to change the energy dissipation rate and produce a segmented energy absorber within a single substrate portion.

[0027] Two parameters of the base material can be modified to control energy dissipation. One parameter is that the base material itself can be changed to adjust the forces and energies associated with fracture. For example, a material grade of steel sheet with a specific yield strength and ductility can be selected to produce the desired force and energy dissipation rate during fracture. In addition, different materials, such as plastic, steel, or aluminum, can be selected to produce the desired fracture behavior.

[0028] The second parameter is that the substrate thickness can be modified to control the fracture and energy dissipation of the material. The thickness of the material can be used to control the fracture mode and the amount of energy dissipated in the fracture. Multiple layers of material can be combined at a given location to change the resistance and energy dissipation, such as by welding metal layers on top of each other. Further different thicknesses of material can be placed end to end to change the force level and energy dissipation at any location.

[0029] The energy dissipation mechanism described above was developed for use in the valleys of a series of Thrie Beam plates. However, the method described can be applied to a variety of components and at different locations within the cross-section of a component. Furthermore, the technology described is not limited to crash cushioning systems, but can also be applied to a variety of energy dissipation systems used in roadside hardware and other impact absorbing structures.

[0030] The present invention and additional features and advantages thereof may be best understood by referring to the following description taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is an isometric view of an exemplary embodiment of a crash attenuator constructed in accordance with the principles of the present invention, arranged in a deployed orientation;

[0032] Figure 2 yes Figure 1 A top view of a collision attenuator;

[0033] Figure 3 yes Figure 1 A front view of a collision attenuator;

[0034] Figure 4 yes Figure 3 Detailed diagram of middle section 4;

[0035] Figure 4A-4G yes Figure 4 Various views of the bent washer plate and bolt assembly shown;

[0036] Figure 5 is along Figure 3 Sectional view along line 5-5;

[0037] Figure 6 is along Figure 3 Sectional view along line 6-6;

[0038] Figure 7 is along Figure 3 Sectional view along line 7-7;

[0039] Figure 8 is along Figure 3 Sectional view along line 8-8;

[0040] Fig. 9 is a front view of an exemplary embodiment of an impact head assembly of the present invention;

[0041] Fig.10 yes Fig. 9 A top view of an impact head assembly;

[0042] Fig.11 yes Fig. 9 and Fig.10 A cross-sectional view of an impact head assembly;

[0043] Fig.12 is a front view of an exemplary embodiment of a middle partition assembly of the present invention;

[0044] Fig.13 yes Fig.12 A top view of the intermediate partition assembly shown;

[0045] Fig.14 yes Fig.12 and Fig.13 A cross-sectional view of the intermediate partition assembly shown;

[0046] Fig.15 is a front view of an exemplary embodiment of a support structure assembly of the present invention;

[0047] Fig.16 yes Fig.15 A top view of the support structure assembly is shown;

[0048] Fig.17 yes Fig.15 and Fig.16 a cross-sectional view of the support structure assembly shown;

[0049] Fig.18 is a top view of an exemplary embodiment of a track assembly of the present invention;

[0050] Fig.18A yes Fig.18 A top view of the inset area 18A is shown;

[0051] Fig.18B yes Fig.19 A front view of the illustrated area 18B;

[0052] Fig.19 yes Fig.18A front view of a track assembly;

[0053] Fig. 20 is similar to Fig.18 A top view of an exemplary embodiment of a track assembly of the present invention;

[0054] Fig.21 yes Fig. 20 A front view of a track assembly;

[0055] Fig. 22 is along Fig.21 A cross-sectional view taken along line 22-22;

[0056] Fig.23 is along Fig.21 A cross-sectional view taken along line 23-23 of ;

[0057] Fig.24 is a front view of an exemplary embodiment of a first track assembly of the present invention;

[0058] Fig.25 is along Fig.24 A cross-sectional view of line 25-25;

[0059] Fig.26 is a front view of an exemplary embodiment of a second track section assembly of the present invention;

[0060] Fig. 27 yes Fig.26 a cross-sectional view of the second track assembly shown;

[0061] Fig.28 yes Fig.26 A front view of the portion numbered 28;

[0062] Fig.29 is a front view of an exemplary embodiment of a third track assembly of the present invention;

[0063] Fig.30 yes Fig.29 a cross-sectional view of the third track assembly shown;

[0064] Fig.31 yes Fig.29 A front view of reference numeral 31;

[0065] Fig.32 is a front view of an exemplary embodiment of a fourth and fifth track assembly of the present invention;

[0066] Fig.33 yes Fig.32 a cross-sectional view of the fourth and fifth track assemblies shown;

[0067] Fig.34 yes Fig.32A front view of the portion indicated by reference numeral 34; and

[0068] Fig.35 yes Fig.32 A front view of the portion designated by number 35. DETAILED DESCRIPTION

[0069] Referring now more particularly to the accompanying drawings, Figure 1-Figure 3 An exemplary embodiment of a fixed crash impact attenuator or crash cushioning system 10 of the type described above is shown, wherein the design is sacrificial in that it is repaired or replaced after a crash. It is therefore designed to be relatively inexpensive and simple in design and construction, yet highly effective in protecting vehicle occupants that directly or obliquely impact the attenuator.

[0070] The energy dissipation mechanism of the present invention is a tearing member that is forced through a substrate to dissipate energy through the fracture of the substrate. The innovation of the system of the present invention is partly because it can control and change the force level and energy dissipation of the substrate fracture through several parameters, including the use of different types of tearing members, changing the cross-section of the substrate through various forms of holes, cuts, and stress concentrators, as well as changes in the substrate itself. Modifications to these aspects of the energy dissipation mechanism allow the force level and energy dissipation generated by the material fracture to be changed by changing the fracture mode, the number of fracture surfaces, and the length of the material fracture. In its simplest form, energy dissipation can include forcing the tearing member to pass through a constant cross-section of the substrate to form a single fracture line. Alternatively, the introduction of various modifications, such as those listed in this article, can produce multiple fracture modes along multiple fracture lines to achieve more sophisticated energy dissipation.

[0071] Design considerations for the system 10 are that it is designed and tested to meet the U.S. Federal TL (Test Level)-3 crash attenuation specifications, it has a narrow profile, has bidirectional capabilities, is MAS (Safety Hardware Assessment Manual) compatible, is inexpensive and self-contained (does not require docking with a rigid object, although it is capable of such connection). The system is simple in design, easy to manufacture (materials are standard sizes and shapes, and the side panels are based on standard three-corrugated steel plate beams (Thrie Beams, such as AASHTO M-180 profiles), easy to assemble, and can be shipped as a complete assembly. The base is a drilling template that allows anchor holes to be drilled with the unit 10 assembled. In an exemplary embodiment, the length of the designed unit is approximately 20-24 feet. Its width is 32 inches or less, which allows three units 10 of this width to be transported on a truck. In an exemplary embodiment, the height can range from 31 inches to 36 inches. The unit 10 can be anchored to concrete, asphalt, or a mixture of the two, and can be anchored using standard anchors and adhesives. It is suitable for use in temperatures ranging from below -40 degrees to 150+ Fahrenheit.

[0072] The system 10 includes a base or track assembly 12 having a ladder frame design, such as Figure 2 1, including a plurality of intermediate base plates 14 that support a first outer rail 16 and a second outer rail 18, respectively, and having a larger end base plate 15 at each end. The intermediate base plates 14 and the end base plates 15 each include an anchor hole 20 for anchoring the base to the ground using a bolt anchor 22 or other suitable mechanical fastener. In some cases, an adhesive may be used instead or in addition. In the illustrated embodiment, the anchor holes 20 may be spaced apart along the length of each base plate 14, 15 on the outside and inside of the first outer rail 16 and the second outer rail 18.

[0073] The system 10 also includes an upper attenuator portion 24, which includes an impact head assembly 26, a plurality of intermediate baffles 28, including an intermediate baffle assembly extending between the impact head assembly and the support structure assembly, and a plurality of side panels 30. The impact head assembly 26 may include an object marker located at a front end thereof, which may include a warning strip, etc., and includes a crushable nose box or energy absorber 32 in the exemplary illustrated embodiment. In the illustrated embodiment, the crushable box 32 is filled with a honeycomb material that is particularly suitable for being crushed and compacted to attenuate impact forces (for clarity, the crushable box 32 is filled with a honeycomb material that is particularly suitable for being crushed and compacted to attenuate impact forces). Figure 9-11 Honeycomb is not shown in the figure. Of course, suitable attenuating materials other than honeycomb may be used if desired. Impact head 26 supports loads applied by frontal, side, and oblique front end impacts.

[0074] The intermediate baffles 28 are disposed in spaced relation behind the impact head 26. They are made of standard shapes and sizes and have cross braces or brace tubes sized to accommodate the loads. Each cross brace is positioned to facilitate assembly of the side panels 30. As shown, each intermediate baffle 28 is slidably mounted to the side rails 16, 18 at their bottom end or feet 34 on each side. The rails 16, 18 are T-shaped and the feet 34 on the baffles 28 are of "T-slot" construction so that they completely surround and wrap around the upper flange portion of the "T" of the T-shaped track. This is, for example, Figure 7-Figure 8 As can be seen from these illustrations, this unique configuration allows for the distribution of lateral loads from an oblique impact to both rails 16, 18, whereas prior art crash buffers, which typically utilize "C-shaped" rails, only allow for lateral loading on the adjacent rails.

[0075] The side panels 30 may be standard in construction and, in the case of a crash cushion of the type shown, may include a corrugated beam, such as a standard Thrie beam or W-beam, preferably made of 10 or 12 gauge steel. Plates or tubes may also be used. When a vehicle collision occurs and the attenuator is compacted, the center partition continuously moves toward the rear of the crash attenuator 10 by sliding along the tracks 16, 18. With this sliding of the center partition 28, the side panels 30 move rearwardly with the center partition to which they are attached, advantageously designed to nest or overlap each other in a sliding mode. This mechanism will be described in more detail below.

[0076] The length of the side panels 30 may be determined by the load in a side or oblique impact and may depend, at least to some extent, on the spacing of the baffles. The side panels are preferably designed to be universal and interchangeable where possible, although of course only for use with other side panels designed for similar stages of the attenuator system. Figure 4-Figure 8 As shown, bolt and bent washer plate assemblies 36 secure each side plate 30 to the corresponding intermediate partition 28, and to the adjacent side plates 30 to the impact head 26 or support structure assembly 44. Each bolt assembly may include a winged bent washer plate 38 and secured by a bolt 40 having a bolt head 42. This shaped washer plate configuration has the advantage of controlling the fracture path and movement of the side plates in a more favorable manner. The steel forming the side plates may be galvanized and may be, for example, A36, A513 or A517 steel. Figure 4A-4G An isometric view of the bolt and curved washer plate assembly 36 is shown separately, showing the curved washer plate 38 having curved wings 38a and a center portion 38b. The use of flared front wings 38a on the washer plate 38, and the forward positioning of the bolt 40, shortens the distance to the shank face, thereby limiting the buildup in front of the tearing member (bolt) 40 and under the washer. This contoured washer plate also helps control the break path and side plate movement during the tearing process. Figure 4B yes Figure 4A A side view of the components, Figure 4C is a front view, Figure 4D shows the flat pattern of the curved gasket plate 38, Figure 4E Yes Figure 4D The plan view of the plate bending gasket plate is shown in side view. Figure 4F is a front view of the bent gasket plate 38, Figure 4G is an outline view of the bent washer plate 38. The central portion 38b of the bent washer plate 38 includes a hole 39 for receiving a bolt 40.

[0077] like Figure 5 and Figure 9-11 As shown more particularly in , the impact head assembly 26 may include, in addition to the collapsible box 32 , an upright support 46 having a bottom end 47 similar to the bottom end of the intermediate partition 28 or foot 34 , but longer and adapted to slide along the rails 16 and 18 .

[0078] Figure 6 and Figure 15-18B A support structure assembly 44 is shown, which includes upright posts 48 and angled support brackets 50 ( Figure 1-Figure 3 and Figure 15-17 ). Upright posts 48 and angled support brackets 50 comprise end base plates 15 which may be anchored in the ground using bolt anchors 22. It should be noted that the specific structural features of the support structure assembly 44 may vary depending on the desired application and that end treatment hardware of known design may be used to secure the crash attenuator 10 to the fixed structure being protected, if desired.

[0079] Figure 7-Figure 8 and Figure 12-14 The intermediate partition 28 comprising the intermediate partition assembly is shown in greater detail. The partition 28 includes upright posts 54 at the lower ends of which are provided with bases or feet 34. The posts 54 are secured together by cross members 56.

[0080] Figure 18-Figure 23 An exemplary embodiment of a track assembly 12 is shown in particular detail and includes a first side rail 16 and a second side rail 18 respectively secured to longitudinally spaced apart intermediate base plates 14. At both ends of the crash attenuator 10, the rails 16, 18 extend longitudinally of a larger end base plate 15 anchored thereto to support an impact head at one end and a support structure assembly at a second end.

[0081] like Figure 2 As particularly shown in FIG, in a frontal collision, the impacting vehicle may impact the nose or impact head 26 in a left to right direction, as shown by arrow 58. The system can also mitigate collisions caused by vehicle impacts from the side or angle. In order to adjust and control the attenuation characteristics of the collision attenuator 10, the upper attenuator portion is divided into multiple stages. In the illustrated exemplary embodiment, the upper attenuator portion 24 includes a first track assembly 60, a second track assembly 62, a third track assembly 63, a fourth track assembly 66, and a fifth track assembly 68, each of which includes a uniquely designed panel with smooth transitions between the panels / sections. The resulting inertial pulse elongation reduces force peaks, thereby improving the safety of vehicle occupants.

[0082] The present invention utilizes an energy absorbing mechanism employed in a crash attenuator system, which is a design pattern in which the components of the attenuator system tear apart when absorbing the forces applied by the impacting vehicle. In the illustrated embodiment, the energy absorbing method uses a plate connection hardware consisting of a bolt assembly 36 as the tearing hardware to tear the side panel or guard plate 30. Of course, other system components are used as the torn objects, as well as other tearing members, such as independent gasket plates / assemblies or other piercing elements, such as rods, plates, wedges, etc., as the tearing hardware. The form of the tearing member can be used to specify the fracture mode and the number of fracture surfaces formed in the substrate, as well as to control the propagation of the fracture path through the substrate. Multiple tearing members can be used in a section of the substrate to produce additional fracture surfaces and increase the force level and energy dissipation.

[0083] Particularly innovative is that the system is designed to adjust tearing and shearing in a controlled manner to maximize the impact force attenuation capability and minimize the damage to the vehicle occupants, allowing the vehicle occupants to withstand a knock-down force that is significantly lower than the permitted level under the federal collision standards. Methods for adjusting the tearing level include, but are not limited to, adjusting the thickness of the component to vary along each section of the attenuator, managing the tearing process using cuts in the component to be torn, ranging from a component consisting of solid material to a series of holes of different configurations and spacings, such as grooves, triangles (including isosceles triangles and equilateral triangles), trapezoids, semicircular / crescent shapes, perforations, rectangles, etc. As described above, the cut size and the spacing between the holes can vary. Multiple rows of holes can be used in each component, where the holes are aligned or staggered relative to the holes in adjacent rows. One purpose of this adjustment can be to initiate one, two or three different types of tearing modes, depending on the shape / pattern of the holes and their spacing and the thickness of the component, including mode 1 (tensile failure), mode 2 (shear failure), mode III (out-of-plane shear), and combinations of the aforementioned modes. The control of tearing is designed to produce a consistent and predictable path, which is created by the planned use of perforations, pattern spacing, grooves or scoring, and the design of the tearing pattern, which in the exemplary embodiment involves an innovative washer plate design used with the bolt assembly 36, where the wing-shaped washer 38 has a limited front extension to allow the guard plate to curl and prevent pile-up. Various materials can be used for the assembly being torn (such as the guard plate 30 in the exemplary embodiment), such as various steels, aluminums, plastics, and FRP (fiber reinforced plastics). As mentioned above, pattern staggering can be used to limit force peaks, and the tearing can occur through the valleys or peaks of the track or anywhere on the plate.

[0084] It should be noted that at this time, the terms "tear", "tearing", "tearable", etc. are used herein and in the appended claims as substitutes for any of the above terms for forming elongated cracks or slits in a crash attenuator component to attenuate the energy of an impact, and are intended to be broad enough to include any of these terms.

[0085] Considering the above, Figure 24-25 An exemplary first section (section 1) of the crash attenuator 10 is shown, which includes a first protective plate 30 disposed in an opposing manner along two sides of the attenuator system 10, as shown in FIG. Figure 2 and Figure 3 As shown, the plate 30 in section 1 includes two rows 74, 76 of longitudinally arranged and spaced holes 78, which in this particular embodiment are in the shape of triangles, or more specifically isosceles triangles. Each row 74, 76 is aligned with a corresponding bolt hole 70 for receiving a bolt 40 of the plate bolt assembly 36. Position 72 accommodates a gusset welded to the back of the three-corrugated steel plate beam guard plate 30. The gusset strengthens the place where the shear bolt 40 passes through the plate, thereby forcing the downstream bolts to extrude through the plate. Wing washers 38 are welded to the corresponding shear bolts 40. As shown Fig.24 As shown, an elongated slot 80, which may also be circular, oval or other shape, is provided at the rear end of each row 74, 76. The purpose of the slot 80 is to receive the bolt 40 of the bolt assembly that secures the front end of the next overlapping panel 30 to the second intermediate partition 28 in the initial deployed state of the crash attenuator 10. The use of slots, teardrops and other special shapes helps to concentrate stress at the beginning of the panel, thereby facilitating the initiation of fracture. The first panel is connected to the impact head 26 at the front, spans the first intermediate partition 28, and is then bolted to the second intermediate partition 28. When the vehicle applies an impact force in the direction of arrow 58 ( Figure 2 ), the first plate 30 is accelerated from left to right in the figure, riding with the impact head 26 connected to their respective front ends, so that the oval slot 80 is the location where the tearing bolt 40 will begin the tearing process, and the bolt moves forward relative to the plate until the bolt 40 reaches the front end of the plate 30 at the leftmost end of its respective row 74, 76. Because the tearing action initiated by the bolt 40 in the material of the plate 30 will produce a fracture or crack that propagates forward along the plate, even if the plate moves rearward due to the impact force 58 of the vehicle, the rearmost end of the plate is softer than or consistent with the frontmost end of the plate, as described above.

[0086] Because Section 1 is the first section to receive and attenuate the impact force, it is designed to be the softest, with each successive section being designed to be stiffer than the previous one. In Section 1, as described above, the hole 78 can be triangular, and more specifically an isosceles triangle in a particular embodiment. The triangular shape is particularly suitable for a single mode 1 crack without debris. During impact, the tear bolt 40 moves through the plate 30 from right to left in the opposite direction of the plate, as described above. As the tear bolt 40 moves into the triangular hole 78, the bolt strikes the two diverging sides of the triangle, creating a tensile load at the left point of the triangle. As described above, this will induce mode 1 tensile failure in the material ahead of the tear bolt, and occasionally mode II shear will also occur, especially at the beginning of the tearing process.

[0087] As mentioned above, Section 2, such as Figure 26-Figure 28 Shown is the next section, and the next fender plate 30 to be impacted. It is designed to be stiffer than section 1, but still relatively soft, since the impact forces are still high after only being attenuated by the impact head and the plate of section 1. In section 2, the plate 30 has two rows 74, 76 of holes 82, along the same locations as in section 1. These holes 82 are also shown as triangles, but are smaller in nature than the holes in section 1, and are more closely spaced. The triangles can be isosceles triangles, or, as shown, equilateral triangles, but can also be alternative shapes, such as circular, trapezoidal, rectangular, etc. In the illustrated embodiment, there are thirty-three holes 82 in each row 74, 76 along a length of 32 inches. Of course, this is merely an exemplary number, as the actual number of holes and the spacing between them can vary, depending on design considerations. Larger elongated holes 84 are provided at the downstream (rightmost) end of each row 74, 76 for accommodating bolts 40 that secure the plate 30 to the corresponding intermediate partition 28. As the impact force continues, the plate 30 moves to the right, causing the tear-off bolts 40 to move leftward (forward) (in a relative sense) along their respective rows 74 , 76 .

[0088] The next plate 30 includes a section 3, such as Figure 29 to Figure 31 This section looks similar to section 2, and the hole shape is the same, but in this exemplary embodiment, along 31 1 Each row 74, 76 of 1 / 2 inch length has 29 holes 85. Thus, the plate 30 of section 3 is "harder" than the plate 30 of section 2 because the holes 85 are fewer and more widely spaced than the holes 82 of the plate of section 2.

[0089] Sections 4 and 5 are shown in Figure 32-Figure 35, where the fourth and fifth sections of the protective plate 30 also have two rows of holes 74, 76. In the illustrated embodiment, the same plate 30 is used for sections 4 and 5, and the plate utilizes trapezoidal holes 86. The purpose of the circular holes 90 is to initiate tearing at this section. It should be noted that in sections 4 and 5, the relative axial positions of the trapezoidal holes 86 in each row 74 and 76 are staggered, rather than aligned. The purpose of this staggering is to produce a more uniform force attenuation to smooth the peaks and valleys of the force deflection curve. The trapezoidal shape is very suitable for dual-mode fracture of mode II / mode III.

[0090] If desired, the plate 30 of the rear section may be constructed of thicker material than that of the front section in order to further strengthen the rear section relative to the front section.

[0091] As discussed above, the illustrated embodiments are exemplary only, and different numbers of hole rows, different shapes of holes, different spacings, staggering, etc. may be employed to produce the desired attenuation characteristics. For example, an alternative exemplary embodiment uses isosceles triangles in Section 1, equilateral triangles of various sizes and spacings in Sections 2 and 3, and trapezoids of also various sizes and spacings in Sections 4 and 5. Rectangles with or without perforations may be used for dual mode fractures of Mode II / Mode III. It should also be noted that while the exemplary embodiments primarily include multiple sections associated with plate transitions, it is also within the scope of a single plate to divide a single plate into multiple sections by changing material thickness, hole size, hole spacing, or other features described herein rather than after transitioning from one plate to the next.

[0092] Advantageously, the present invention contemplates the use of multiple fracture surfaces in a single plate, longitudinal staggering of fracture modification patterns, and alternatingly spaced shaped holes within the plate segments. Of particular note, as shown, the modification (hole) pattern on each plate terminates early before the end of the plate and plate 72 and before full-stroke in order to increase the force to bottom out the current plate and smoothly transition to the start of fracture of the subsequent plate while reducing inertial forces.

[0093] Therefore, although exemplary embodiments of the present invention have been shown and described, it should be understood that all terms used herein are descriptive rather than limiting, and that many changes, modifications and substitutions may be made by those skilled in the art without departing from the spirit and scope of the present invention.

Claims

1. A collision impact attenuator system, the system comprising: an attenuator portion including a plurality of support members including a track extending along the length of the crash impact attenuator system and a plurality of baffles arranged in spaced relationship along the length of the track, each of the plurality of baffles having a bottom end or foot adapted to movably engage the track so that when the crash impact attenuator system receives an impact force from an impacting vehicle, a first of the plurality of baffles moves rearwardly along the track and impacts a second of the plurality of baffles, wherein both the first and second of the plurality of baffles move further rearwardly along the track to sequentially impact other of the plurality of baffles until the impact force is fully attenuated; The attenuator portion further includes a plurality of side panels disposed along one side of the attenuator portion; the plurality of side panels being adapted to slide rearwardly along the attenuator portion when the crash impact attenuator system is impacted by a vehicle, such that a first side panel of the plurality of side panels slides over a second side panel of the plurality of side panels when a first side panel of the plurality of side panels slides rearwardly in response to the vehicle impact, each of the plurality of side panels including a plurality of holes disposed in a material constituting each of the plurality of side panels, the plurality of holes extending along a length of each of the plurality of side panels and being longitudinally spaced apart from one another; as well as a tear member disposed on the attenuator portion, the tear member being adapted to engage one of the plurality of apertures of the material of a first side panel of the plurality of side panels, wherein when the impact attenuator system is impacted by a vehicle, relative movement occurs between the first side panel of the plurality of side panels and the tear member, thereby tearing a crack or slit in the material forming the first side panel of the plurality of side panels, the crack extending between adjacent apertures of the plurality of apertures, the tearing of the side panel material attenuating the impact force, the side panel material being adjusted to optimize the tearing of the side panel material, the adjustment of the side panel material being accomplished by varying the size and arrangement of the plurality of apertures; Wherein a first side panel of the plurality of side panels comprises a first section attenuator portion and a second side panel of the plurality of side panels comprises a second section attenuator portion, the first section attenuator portion is in front of the second section attenuator portion and the first side panel of the plurality of side panels is softer than the second side panel of the plurality of side panels, the plurality of holes of the first side panel of the plurality of side panels are configured to have a first shape to form a tensile failure of mode I, and the plurality of holes of the second side panel of the plurality of side panels are configured to have a second shape different from the first shape to form a shear failure of mode II.

2. The crash impact attenuator system of claim 1, wherein the plurality of side panels comprises a plurality of guard panels.

3. The crash impact attenuator system of claim 1, wherein: The tear member comprises a bolt.

4. The crash impact attenuator system of claim 1, wherein: The tear member is disposed on one of the plurality of separators.

5. The crash impact attenuator system of claim 1, wherein: The tear member comprises a plurality of tear members.

6. The crash impact attenuator system of claim 1, wherein: The plurality of holes form a first row of holes and a second row of holes spaced apart from each other along the height of the side plate on which the plurality of holes are arranged.

7. The crash impact attenuator system of claim 6, wherein each hole of the first row of holes and each hole of the second row of holes formed on the side panel where the plurality of holes are arranged correspond to each other and are longitudinally aligned with each other.

8. The collision impact attenuator system of claim 6, wherein each hole of the first row of holes and each hole of the second row of holes formed on the side plate where the plurality of holes are arranged correspond to each other and are staggered with each other in a longitudinal direction.

9. The crash impact attenuator system of claim 6, wherein the first shape is a triangle and the second shape is a trapezoid.

10. A collision impact attenuator system as described in claim 1, wherein the plurality of side panels also include a third side panel, a fourth side panel and a fifth side panel of the plurality of side panels extending longitudinally rearward of the second side panel of the plurality of side panels, the third side panel of the plurality of side panels includes a third-section attenuator portion, the fourth side panel of the plurality of side panels includes a fourth-section attenuator portion, and the fifth side panel of the plurality of side panels includes a fifth-section attenuator portion, wherein the third side panel of the plurality of side panels is stiffer than the second side panel of the plurality of side panels, the fourth side panel of the plurality of side panels is stiffer than the third side panel of the plurality of side panels, and the fifth side panel of the plurality of side panels is stiffer than the fourth side panel of the plurality of side panels or has the same stiffness as the fourth side panel of the plurality of side panels.

11. The crash impact attenuator system of claim 1, further comprising a nose box disposed at a forward-most end of the crash attenuator system.

12. The crash impact attenuator system of claim 3, wherein the bolt is assembled with a bent washer plate.

13. The crash impact attenuator system of claim 12, wherein the curved gasket plate includes a flared front wing.

14. The crash impact attenuator system of claim 12, wherein the curved washer plate has a limited front extension to allow a first side plate of the plurality of side plates engaged with the curved washer plate to curl and prevent stacking when the first side plate of the plurality of side plates is torn by the bolt.

15. A crash impact attenuator system as described in claim 1, wherein the plurality of holes extend along the length of each of the plurality of side panels and are longitudinally spaced apart from each other, including a row of holes on each of the plurality of side panels, the row of holes extending longitudinally along each of the plurality of side panels and terminating before reaching the front end of each of the plurality of side panels, wherein the termination of the row of holes on each of the plurality of side panels facilitates initiating tearing of the next adjacent side panel of the plurality of side panels, thereby reducing the peak of impact force attenuation when the crash impact attenuator system is compressed.

16. The crash impact attenuator system of claim 1, wherein: The track includes a first track and a second track disposed parallel to each other and extending along the length of the attenuator portion, each of the first track and the second track having a T-shaped configuration including a top flange disposed horizontally and extending along the length of each track, and wherein the bottom end or foot of each of the plurality of baffles includes a first bottom end or foot and a second bottom end or foot, the first bottom end or foot being configured to surround the top flange of the first track and the second bottom end or foot being configured to surround the top flange of the second track, thereby distributing lateral loads from an oblique impact to each of the first track and the second track on the collision impact attenuator system.

17. A method of reducing the impact force exerted by an errant vehicle that would otherwise strike a hazardous object, the method comprising: receiving the impact force at a front end of a crash impact attenuator having a base and an upper attenuator portion; tearing the material constituting the first side panel disposed on the crash impact attenuator, when the first side panel moves in response to an impact force, the tearing of the material of the first side panel acting to attenuate the impact force and including a Mode I tensile failure; as well as Tearing the material of a second side panel initially disposed behind the first side panel, wherein the size and arrangement of the material constituting the second side panel is configured to require a greater tearing force than the material constituting the first side panel, the tearing of the second side panel material comprising a Mode II shear failure.

18. The method of claim 17, wherein: The material tearing step is performed by one or more tearing members, which include one or more protrusions arranged on the upper attenuator portion, wherein one of the one or more tearing members initially engages with a hole formed in the material of the side panel being torn.

19. The method of claim 18, wherein a plurality of holes are longitudinally arranged in a spaced relationship in the material of each of the first and second side panels, and each of the tearing steps comprises tearing the material of the torn side panel between initially joined holes and adjacent holes of the plurality of holes to form a crack or slit in the torn side panel.

20. The method of claim 17, wherein the material forming the second side panel is thicker than the material forming the first side panel.

21. The method of claim 19, wherein the plurality of holes in the first side plate are more closely spaced together than the plurality of holes in the second side plate.

22. The method of claim 21, wherein the plurality of holes in the first side panel are larger than the plurality of holes in the second side panel.

23. The method of claim 19, wherein at least some of the plurality of holes in the first side plate are larger than any of the plurality of holes in the second side plate.

24. The method of claim 19, wherein at least some of the plurality of holes in the first side plate have a shape that is different from the shape of any of the plurality of holes in the second side plate.

25. The method of claim 17, wherein: The second side panel is formed of a different material than the first side panel.

26. The method of claim 19, wherein the plurality of holes on the first side plate are triangular in shape and the plurality of holes on the second side plate are trapezoidal in shape.

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