WO2019100119A1

WO2019100119A1 - Helmet testing

Info

Publication number: WO2019100119A1
Application number: PCT/AU2018/051257
Authority: WO
Inventors: Brayden Scott ROBINSON; Scott Robert ROBINSON
Original assignee: Mickelbobs BBC Patents Pty Ltd
Priority date: 2017-11-23
Filing date: 2018-11-23
Publication date: 2019-05-31

Abstract

A device for testing the structural integrity of a helmet including: an x-ray generator; a space shaped to receive the helmet; and an x-ray detector; wherein the x-ray generator is arranged to eject x-rays through the space; and wherein the x-ray detector is arranged to receive x-rays ejected by the x-ray generator and produce images based on the received x-rays that shows defects in the helmet. Also, a device for testing the structural integrity of a helmet including: a shearography analysis unit; and a space shaped to receive the helmet; wherein the shearography analysis unit is arranged to eject electromagnetic radiation through the space onto the helmet; and wherein a detector is arranged to receive electromagnetic radiation and produce images based on the received electromagnetic radiation that display defects in the helmet.

Description

HELMET TESTING

Field of the Invention

[0001 ] The present invention generally relates to a device and method for testing the integrity of safety helmets.

Background of the Invention

[0002] Helmets such as motorbike helmets are designed to protect a user’s head from forces impacted on the head where a crash or fall occurs. A foam, or foam like core or inner lining is used behind a hard outer skin of the helmet to absorb and distribute the forces impacted onto the helmet. In some instances, unique foam shapes, such as cones, are used to assist with the distribution of force. In some respects, where unique foam shapes are used, the ability of helmet to absorb and distribute force relies on the integrity of these unique shapes. Regardless of the type of helmet, the integrity of the cell structure of the foam is integral to the force absorbing capabilities of the helmet.

[0003] Methods of testing safety helmets such as bicycle or motorbike helmets that include a foam core are currently used. These tests are typically used by a manufacture of the helmets or regulatory body and provide data that can allow a helmet to meet a particular safety standard required for particular uses.

[0004] In one known method of testing, a simulated head including sensors are placed inside a helmet and the helmet is impacted with a variety of forces to simulate a crash or fall. The sensors within the simulated head are then used to take readings of the forces felt on the simulated head. This data is then used to assess the merits of a helmet and its ability to absorb and distribute forces.

[0005] This type of testing is useful in establishing the merits of a new helmet, but does not give a user an indication of the merits of a used helmet that may be old or has experienced a crash or fall.

[0006] In an alternative known method of testing a helmet a helmet is subjected to force that simulate a crash or fall and then the helmet is cut in one or several places to expose the foam core. This allows testing of the foam core to establish how forces were absorbed or distributed. It also gives an indication of the integrity of the foam core after it has experienced a simulated crash or fall. Unfortunately as the helmet is cut, exposing the core, there is no possibility of using the helmet again, even if the foam core’s integrity has been maintained.

[0007] Non-destructive testing using a variety of radiation based technology is a high energy application typically applied to welds, metal pipes and other structures to test their integrity. The high energy of the radiation used in these applications makes their ability to identify details in helmet material not possible. The types of radiation commonly used include x-rays, shearography and laser.

[0008] Reference to cited material or information contained in the text should not be understood as a concession that the material or information was part of the common general knowledge or was known in Australia or any other country.

Summary of the Invention

[0009] It is an object of this invention to provide to ameliorate, mitigate or overcome, at least one disadvantage of the prior art, or which will at least provide the public with a practical choice.

[0010] In a first aspect, the present invention provides an apparatus for testing the structural integrity of a helmet including:

an x-ray generator;

a space shaped to receive the helmet; and

an x-ray detector;

wherein the x-ray generator is arranged to eject x-rays through the space; and wherein the x-ray detector is arranged to receive x-rays ejected by the x-ray generator and produce images based on the received x-rays.

[001 1 ] Preferably, the helmet includes an inner core and shell.

[0012] Preferably, the inner core is expanded polystyrene.

[0013] Preferably, the shell is constructed from a composite material.

[0014] Preferably, the shell is constructed of fiberglass.

[0015] Preferably, the x-ray generator is powered using between 20kV and 80kV.

[0016] Preferably, the x-ray generator is powered using 40kV. [0017] In a second aspect, the present invention provides a method of testing the structural integrity of a helmet, wherein an x-ray generator ejects x-rays at a helmet to an x-ray detector.

[0018] Preferably, the device is housed within a shielded cabinet.

[0019] Preferably, the shielded cabinet is shielded with lead.

[0020] Preferably, the x-rays generated is of sufficient power to pass through an outer layer of a helmet, but identify features in expanded polystyrene.

[0021 ] Preferably, images produced by the x-rays identify compression of the cell structure of the expanded polystyrene.

[0022] Preferably, images produced by the x-rays identify deformation of the cell structure of the expanded polystyrene.

[0023] Preferably, images produced by the x-rays identify tearing of the expanded polystyrene.

[0024] In a third aspect, the present invention provides a device for testing the structural integrity of a helmet including:

a shearography analysis unit; and

a space shaped to receive the helmet;

wherein the shearography analysis unit is arranged to eject electromagnetic radiation through the space onto the helmet; and

wherein a detector is arranged to receive electromagnetic radiation and produce images based on the received electromagnetic radiation that display defects in the helmet.

[0025] Preferably, the helmet is heated externally and internally before testing.

[0026] Preferably, the shearography analysis unit applies a 7mm diagonal shear.

[0027] Preferably, images produced from the shearography analysis unit display cracks in the helmet.

[0028] In fourth aspect, a transportation container is arranged to receive and transport the device. Detailed Description of the Figures

[0029] Further features of the present invention are more fully described in the following description of several non-limiting embodiments thereof. This description is included solely for the purposes of exemplifying the present invention. It should not be understood as a restriction on the broad summary, disclosure or description of the invention as set out above. The description will be made with reference to the accompanying drawings in which:

Figure 1 is a side view of an apparatus for testing the structural integrity of a helmet according to a first embodiment of the present invention;

Figure 2 is a front on x-ray image of a helmet using the apparatus of Figure 1 ;

Figure 3 is a perspective view of a second helmet using the using the apparatus of Figure 1 ;

Figure 4 is a side view x-ray image of the helmet of Figure 3;

Figure 5 is a side view x-ray image of the helmet of Figure 3;

Figure 6 is side view of an x-ray image of the helmet of Figure 3;

Figure 7 is a side view x-ray image of a third helmet using the apparatus of Figure 1 ;

Figure 8 is a top down view x-ray image of the helmet of Figure 7;

Figure 9 is a side view x-ray image of a composite material tested using the using the apparatus of Figure 1 ;

Figure 10 is a side view x-ray image of a composite material tested using the using the apparatus of Figure 1 ;

Figure 1 1 is a schematic view of a shearography apparatus used to test the structural integrity of a helmet according to a second embodiment of the present invention.

Figure 12 is a top down view shearography image of a helmet using the apparatus of Figure 1 1 ; Figure 13 is a side on view shearography image of a helmet using a device according to the second embodiment of the present invention;

Figure 14 is a top down view shearography image of a helmet using the apparatus of Figure 1 1 ;

Figure 15 is side on view shearography image of a helmet using the apparatus of Figure 1 1 ;

Figure 16 is a perspective view of a transportable container according to an embodiment of the present invention; and

Figure 17 is a perspective view of a trailer for transporting the transportable container of Figure 16.

[0030] In the drawings like structures are referred to by like numerals throughout the several views. The drawings shown are not necessarily to scale, with emphasis instead generally being placed upon illustrating the principles of the present invention.

Description of Embodiments

[0031 ] Broadly, the present invention relates to a non-destructive testing (NDT) apparatus for identifying damage to the internal expanded polystyrene (EPS) reinforcing foam of a motorcycle helmet.

[0032] Typically, when a helmet undergoes an impact collision, the foam of the helmet crushes under compression and stretches under tension and tears, all of these processes deforming the cell structure of the foam 12 making it less able to absorb the compressive stresses and strains caused by future impacts. The degree of this crushing, stretching and tearing directly relate to the helmet’s ability to absorb the force of an impact and distribute the force over a wider area.

[0033] The present invention is concerned with electromagnetic wave analysis of a helmet that creates an image displaying defects in the internal structure of the helmet. The below description is concerned with the use of shearography and x-ray beams for the analysis, but it is within the scope of the present invention to use alternative electromagnetic wave analysis methods. The present invention includes using, laser and other non-destructive testing methods that are capable of being used in a readily portable circumstance.

[0034] Referring to Figure 1 , the present invention according to a first embodiment provides a helmet integrity testing system 01 including a portable x-ray generator 03 used to generate an x-ray beam 05 that is incident as a focal spot on detector 07. A helmet 10 is placed between the generator 03 and the detector 07 for the x-ray beam 05 to be incident upon. The x-ray generator 03 is powered by a voltage of between 20kV and 80kV, a current between 2mA and 5mA and a focal spot diameter of between 100pm and 300pm. These voltage, current and focal spot ranges provides sufficient energy for the x-ray beam to penetrate the outer shell of the helmet 10 and detect damage to the EPS foam 12 behind the outer shell of the helmet 10 in significant detail.

[0035] The voltage and current of the generator 03 can be varied in the range of 20kV and 80kV and the current can be varied in the range of 2mA to 5mA to allow the x-ray beam 05 to penetrate the outer shell of the helmet 10 and produce detailed images of the cell structure 17 of the foam 12.

[0036] In one embodiment of the present invention, the x-ray generator is an X-RiS™ GXC-80™ which is suitable to provide the above noted voltage range. In one embodiment the detector used is the X-RiS™ DeRe WA-P™ detector powered by the Maestro™ software platform. The skilled addressee will recognise that alternative x-ray generators and detectors can be used that supply the voltage, current and focal spot diameters discussed above.

[0037] In one embodiment the x-ray generator, and detector are housed in a radiation shielded enclosure arranged so that a motorcycle helmet can be placed in the enclosure in a position so that imaging of the structure of the EPS foam within the outer shell of the helmet can be imaged.

[0038] In one embodiment, the present invention uses a dual energy x-ray scan to produce images. The dual scans are in the range of 20kV to 80kV.

[0039] The image produced by x-ray beam 05 identifies details of the foam 12 and its cell structure allowing the damage to the foam 12 to be identified. It identifies stable regions 16, deformed regions 13, compressed regions 1 1 and torn regions 15. [0040] Referring to Figures 2 to 8, images produced by the x-ray image produced by the helmet integrity testing system 01 are shown illustrating the foam structure 12.

[0041 ] With specific reference to Figure 2, x-ray images taken of a first type of motorcycle helmet, an Airoh™ helmet 10 is illustrated. These images were taken with an x-ray beam of 60kv, 2mA and a focal spot diameter of 200pm. The 60kv voltage level is selected to show definition in the dense foam of the Airoh™ helmet. The cell structure 17 of the foam 12 is illustrated. In stable regions 16 the cell structure 17 is regular indicating that damage from an impact has not occurred. Where this regular cell structure is identified as being maintained, damage to the cell structure of the foam 12 is not suggested. Compressed regions 1 1 show a flattening and merging of the cell structure 17 indicating that the cell structure has been compressed causing damage to the cell structure 17. Cell deformed regions 13 show an altered cell structure, indicating that a stretching of the foam has occurred, weakening the cell structure 17, indicating that damage has occurred to the foam.

[0042] Split regions 15 illustrate a tear or rip of the cell structure indicating that the cell structure 17 has been broken, weakening the force absorbing capacities of the foam 12.

[0043] With specific reference to Figures 3, 4 and 5, x-ray images taken of a first type of motorcycle helmet, a Fox™ helmet 10 is illustrated. These images were taken with an x-ray beam of 40kv, 2mA and a focal spot diameter of 200pm. The cell structure 18 of the foam 12 is illustrated. The cell structure is displayed much smaller than for the Airoh™ helmet. In stable regions 16 the cell structure 18 is regular indicating that damage from an impact has not occurred. Where this regular cell structure is identified as being maintained, damage to the cell structure of the foam 12 is not suggested. Compressed regions 11 show a flattening and merging of the cell structure 17 indicating that the cell structure has been compressed causing damage to the cell structure 17. Cell deformed regions 13 show an altered cell structure, indicating that a stretching of the foam has occurred, weakening the cell structure 17, indicating that damage has occurred to the foam.

[0044] Split regions 15 illustrate a tear or rip of the cell structure indicating that the cell structure 17 has been broken, weakening the force absorbing capacities of the foam 12.

[0045] With specific reference to Figure 6, x-ray images taken of a first type of motorcycle helmet, a Shoei™ helmet 10 is illustrated. These images were taken with an x-ray beam of 40kv, 2mA and a focal spot diameter of 200pm. The cell structure 18 of the foam 12 is illustrated. The cell structure is displayed much smaller than for the Airoh™ helmet. In stable regions 16 the cell structure 18 is regular indicating that damage from an impact has not occurred. Where this regular cell structure is identified as being maintained, damage to the cell structure of the foam 12 is not suggested. Compressed regions 11 show a flattening and merging of the cell structure 17 indicating that the cell structure has been compressed causing damage to the cell structure 17. Cell deformed regions 13 show an altered cell structure, indicating that a stretching of the foam has occurred, weakening the cell structure 17, indicating that damage has occurred to the foam.

[0046] Split regions 15 illustrate a tear or rip of the cell structure indicating that the cell structure 17 has been broken, weakening the force absorbing capacities of the foam 12.

[0047] With specific reference to Figures 7 and 8, x-ray images taken of a first type of motorcycle helmet, a Bell™ helmet 10 is illustrated. These images were taken with an x-ray beam of 40kv, 2mA and a focal spot diameter of 200pm. The cell structure 18 of the foam 12 is illustrated. The cell structure is displayed much smaller than for the Airoh™ helmet. In stable regions 16 the cell structure 18 is regular indicating that damage from an impact has not occurred. Where this regular cell structure is identified as being maintained, damage to the cell structure of the foam 12 is not suggested. Compressed regions 11 show a flattening and merging of the cell structure 17 indicating that the cell structure has been compressed causing damage to the cell structure 17. Cell deformed regions 13 show an altered cell structure, indicating that a stretching of the foam has occurred, weakening the cell structure 17, indicating that damage has occurred to the foam.

[0048] Split regions 15 illustrate a tear or rip of the cell structure indicating that the cell structure 17 has been broken, weakening the force absorbing capacities of the foam 12.

[0049] With reference to Figure 9, a test of a composite material using an x-ray beam of 40kv, 2mA is illustrated. This shows delamination 23, stable regions 16, tears 15, foam material 12 and a cell structure.

[0050] Figure 10 illustrates a reinforced carbon tube illustrating clear regions 16, cell structure 17 and cracks 15. This image was taken using an x-ray beam of 40kv, 2mA. [0051 ] Figure 1 1 shows a shearography testing set up 30 used in a second embodiment of the present invention. The testing set up 30 includes a laser source 36 that emits a laser 32 onto the imaged object 34, in this case a helmet. A reflected laser 38 is projected off the imaged object 34 to be reflected off mirrors 31 and lens 33 into detector 35 to produce an image of the imaged object 34.

[0052] Shearography is a NDT technology that is aimed to monitor the derivative of the skin displacement of the sample monitored. It is an optical interferometric technology and physically our system can be compared to a misaligned Michelson interferometer. Working on displacement derivative enables shearography to get rid of rigid body translation that disturbs other interferometric methods. Defect detection is a good application since actual values displacement are not often required and end user focus on field uniformity for spotting eventual defects.

[0053] Referring to Figures 12 to 15, the present invention, in a second embodiment provides a helmet integrity testing system 51 including a portable shearography testing unit to non-destructively test for defects in a helmet. A helmet 50 is imaged and detects damage 52 to the EPS foam behind the outer shell of the helmet 50 in significant detail.

[0054] With specific reference to Figures 13 to 15, to produce the images a thermal load was applied to the helmet during testing. As the elements of the helmet expand internal stresses are transferred to the surface where they are more easily detected during shearography analysis. For these images a 1 100W Flalogen lamp to introduce the thermal load externally and a 20W lamp internally, a 7mm diagonal shear and placing the helmet 1.4m from the detector was used. The skilled addressee will understand that alternative arrangements can be used and fall within the scope of the present invention.

[0055] Referring to Figure 13 a shearography image 51 of a helmet 50 following a 5m fall is shown. Crack damage 52a on the left upper portion of the helmet 50 is shown in the image 51 indicating damage to the helmet indicating that the helmet should no longer be used.

[0056] Referring to Figure 14 a shearography image 51 of a helmet 50 following a 5m fall is shown. Compression damage 52b on the top left portion of the helmet is shown in the image 51 indicating damage to the helmet indicating that the helmet should no longer be used. [0057] Referring to Figure 15 a shearography image 51 of a helmet 50 following a 3m fall is shown. Deformation 52c indicating damage on the upper left portion of the helmet is shown in the image 51 indicating that the helmet should no longer be used.

[0058] Referring to Figure 16, a transportation container 60 is illustrated for transporting the non-destructive testing apparatus of the present invention. This allows the non-destructive testing apparatus to be moved to the location where events that require helmets are being undertaken to test the integrity of the helmets. For example, the container 60 can be taken to the location of a motorcycle race and the helmets can be tested for damage before racing.

[0059] The transportation container 60 includes an internal space 61 where the non-destructive testing apparatus is located. The transportation container 60 is transported on the trailer 70 for mobile testing.

[0060] With reference to Figure 17, the trailer 70 is shown in more detail. The trailer includes a frame 71 arranged to receive the transportation container 60. Fixing lugs 72 are located on the trailer 70 and are arranged to align with and lockably engage with fixing points 62 on the transportation container 60. The transportation container 60 is arranged to be lifted off the trailer 70. Connection means 74 is arranged to connect to a transportation vehicle to move the trailer and transportation container 60.

Example

[0061 ] The transportation container 60 is towed by a vehicle such as a car to an event where helmets will be required for head safety to reduce the likelihood of traumatic brain. These vents could include motorcycle races, bicycle races, motor vehicle races, skiing races or otherwise as understood by the skilled addressee. Flelmet integrity testing system 01 or shearography testing set up 30 is located within the transportation container 60. Flelmets are tested in the transportation container before races to ensure the integrity of the helmets.

Alterations and Modifications to the Embodiments

[0062] It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

[0063] Modifications and variations such as would be apparent to the skilled addressee are considered to fall within the scope of the present invention. The present invention is not to be limited in scope by any of the specific embodiments described herein. These embodiments are intended for the purpose of exemplification only. Functionally equivalent products, formulations and methods are clearly within the scope of the invention as described herein.

[0064] Reference to positional descriptions, such as lower and upper, are to be taken in context of the embodiments depicted in the figures, and are not to be taken as limiting the invention to the literal interpretation of the term but rather as would be understood by the skilled addressee.

[0065] Throughout this specification, unless the context requires otherwise, the word “comprise” or variations such as“comprises” or“comprising”, will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

[0066] Any reference to prior art contained herein is not to be taken as an admission that the information is common general knowledge, unless otherwise indicated.

[0067] Also, future patent applications maybe filed in Australia or overseas on the basis of, or claiming priority from, the present application. It is to be understood that the following provisional claims are provided by way of example only, and are not intended to limit the scope of what may be claimed in any such future application. Features may be added to or omitted from the provisional claims at a later date so as to further define or re-define the invention or inventions.

Claims

CLAIMS:

1. A device for testing the structural integrity of a helmet including:

an x-ray generator;

a space shaped to receive the helmet; and

an x-ray detector;

wherein the x-ray generator is arranged to eject x-rays through the space; and wherein the x-ray detector is arranged to receive x-rays ejected by the x-ray generator and produce images based on the received x-rays that shows defects in the helmet.

2. A device in accordance with Claim 1 , wherein the helmet includes an inner core and shell.

3. A device in accordance with Claim 1 or Claim 2, wherein the inner core is expanded polystyrene.

4. A device in accordance with any one of the preceding claims, wherein the shell is constructed from a composite material.

5. A device in accordance with any one of the preceding claims, wherein the shell is constructed of fiberglass.

6. A device in accordance with any one of the preceding claims, wherein the x-ray generator is powered using between 20kV and 80kV.

7. A device in accordance with any one of the preceding claims, wherein the x-ray generator is powered using 40kV.

8. A device in accordance with any one of the preceding claims, wherein the device is housed within a shielded cabinet.

9. A device in accordance with any one of the preceding claims, wherein the shielded cabinet is shielded with lead.

10. A device in accordance with any one of the preceding claims, wherein the x-rays generated is of sufficient power to pass through an outer skin of a helmet, but identify features in expanded polystyrene.

11. A device in accordance with any one of the preceding claims, wherein images produced from the x-rays display the cell structure of the foam.

12. A device in accordance with any one of the preceding claims, wherein the images produced from the x-rays display compression of the cell structure of the foam.

13. A device in accordance with any one of the preceding claims, wherein the images produced from the x-rays display tearing of the cell structure of the foam.

14. A device for testing the structural integrity of a helmet including:

a shearography analysis unit; and

a space shaped to receive the helmet;

15. The device of Claim 14, wherein the helmet is heated externally and internally before testing.

16. The testing device of Claim 14 or Claim 15, wherein the shearography analysis unit applies a 7mm diagonal shear.

17. The device of any one of Claims 14, 15 or 16, wherein images produced from the shearography analysis unit display cracks in the helmet.

18. A transportation container arranged to receive and transport the device of any one of the preceding claims.