WO2022118154A1 - Procédé de test d'équipement de protection - Google Patents

Procédé de test d'équipement de protection Download PDF

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Publication number
WO2022118154A1
WO2022118154A1 PCT/IB2021/061011 IB2021061011W WO2022118154A1 WO 2022118154 A1 WO2022118154 A1 WO 2022118154A1 IB 2021061011 W IB2021061011 W IB 2021061011W WO 2022118154 A1 WO2022118154 A1 WO 2022118154A1
Authority
WO
WIPO (PCT)
Prior art keywords
protection equipment
percussion
microphone
protection
equipment
Prior art date
Application number
PCT/IB2021/061011
Other languages
English (en)
Inventor
Hans-Ueli JOHNER
Jean-Daniel Lüthi
Philippe DRAPELA
Douglas VUILLE
Nicolas MOUTARLIER
David THÉVENAZ
Quentin FATTON
Patrick FOLLY
Original Assignee
Haute Ecole Arc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Haute Ecole Arc filed Critical Haute Ecole Arc
Priority to EP21819588.1A priority Critical patent/EP4256287A1/fr
Publication of WO2022118154A1 publication Critical patent/WO2022118154A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
    • G01H13/00—Measuring resonant frequency
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F41—WEAPONS
    • F41H—ARMOUR; ARMOURED TURRETS; ARMOURED OR ARMED VEHICLES; MEANS OF ATTACK OR DEFENCE, e.g. CAMOUFLAGE, IN GENERAL
    • F41H1/00—Personal protection gear
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F41—WEAPONS
    • F41H—ARMOUR; ARMOURED TURRETS; ARMOURED OR ARMED VEHICLES; MEANS OF ATTACK OR DEFENCE, e.g. CAMOUFLAGE, IN GENERAL
    • F41H5/00—Armour; Armour plates
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
    • G01H11/00—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by detecting changes in electric or magnetic properties
    • G01H11/06—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by detecting changes in electric or magnetic properties by electric means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F41—WEAPONS
    • F41H—ARMOUR; ARMOURED TURRETS; ARMOURED OR ARMED VEHICLES; MEANS OF ATTACK OR DEFENCE, e.g. CAMOUFLAGE, IN GENERAL
    • F41H1/00—Personal protection gear
    • F41H1/02—Armoured or projectile- or missile-resistant garments; Composite protection fabrics
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F41—WEAPONS
    • F41H—ARMOUR; ARMOURED TURRETS; ARMOURED OR ARMED VEHICLES; MEANS OF ATTACK OR DEFENCE, e.g. CAMOUFLAGE, IN GENERAL
    • F41H1/00—Personal protection gear
    • F41H1/04—Protection helmets
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F41—WEAPONS
    • F41H—ARMOUR; ARMOURED TURRETS; ARMOURED OR ARMED VEHICLES; MEANS OF ATTACK OR DEFENCE, e.g. CAMOUFLAGE, IN GENERAL
    • F41H5/00—Armour; Armour plates
    • F41H5/06—Shields
    • F41H5/08—Shields for personal use, i.e. hand held shields

Definitions

  • the present invention concerns a fast and reliable method for testing safety equipment, such as bullet protection plate, helmet or protection shields.
  • Wearable devices are commonly used for human protection during dangerous operations. Such equipment is used in particular for military operations, or police interventions against manifestants, or any other human confrontation. Protection equipment includes for example a helmet, a protection shield, or a bullet protection plate, directly placed on the body. It is crucial that the protection equipment is fully operational and resists to the projectiles, the shocks, or any weapon that may be used against the user.
  • Optical analysis using X ray technology is known to investigate some material defects. This technology allows to identify some structural visible defects such as fractures, impacts, surface wearing or related defects. However, some defects might be difficult to visualize using 2D x-ray radiography, e.g. fissures in the longitudinal axis of ballistic plates. It is thus possible that a protection equipment appears good and operational after visual inspection and X ray investigation whilst its global structure is fragilized and would not withstand strong impacts. In addition, X ray analysis usually requires costly installation and a qualified person is needed to be able to use such a complex tool and properly interpret the images. Furthermore, X-ray irradiation represents a risk that needs to be strictly managed.
  • Wearable protection equipment usually does not relate to precise mechanical parts and thus does not need sophisticated measurement tools as those currently used in the mechanical industry.
  • the protection equipment and in particular the ballistic protective plates, are usually made of a combination of materials such as a ceramic plate reinforced with polymeric fibers or other plastic materials on its surface
  • the structure of typical ballistic plates is complex compared to usual metallic objects or other conventional materials.
  • the characteristics of such systems might be very specific to a given design so that a test method optimised for a specific object may not be directly applicable to another similar object. Differences might even exist between several production lots.
  • Known acoustic testing methods, applied on conventional homogenous materials may provide less accurate results on heterogenous materials such as composite or multi-component materials.
  • An aim of the present invention is the provision of a method for testing the safety equipment, such as helmets or bullet protection plates that allows to reliably determine their resistance performance.
  • Safety equipment, or protection equipment preferably denotes wearable equipment used against strong impacts to protect the body. They may also denote equipment arranged at distance from the users, such as protection screens or equivalent, to protect them.
  • the protection equipment here described is also applicable to civil activities where people need to be protected against dangerous projections or impacts.
  • the protection equipment here described may be applied to the protection of vehicles or even parts of buildings
  • Another aim of the invention is to provide an accurate method of testing a material, and in particular ceramic, composite, and/or multicomponent materials, in a non-destructive manner, in combination, in complement or in replacement of traditional X-ray imaging or other usual testing methods.
  • Another aim of the present invention is to provide a method for testing protection equipment, in particular those comprising or made of ceramic, composite, or multi-component materials which is fast and reliable, and easily applicable on site of operations.
  • Another aim of the present disclosure is to provide a method which is flexible and easily adaptable to a variety of different protective equipment.
  • Another aim of the present disclosure is the provision of a method of management of protection equipment, in particular with regards to the life cycle management and the replacement planification.
  • Another aim of the present invention is to provide a method allowing performant logistic of the protection equipment, and allowing certifying on site the quality of such equipment.
  • the invention provides the advantage of a specific non-destructive test method, easily applicable on site in a cost effective manner.
  • the present method is in addition versatile and applicable to a variety of different materials, including ceramic based materials.
  • Figure 1 Schematic representation of steps b), c) and d) of the method according to the present disclosure.
  • Figures 2a, 2b representations of an acceptable and a non- acceptable profile. Examples of embodiments of the present invention
  • a protection equipment 1 may be used as a clothing element placed on the body to stop bullets and avoid shutting of the person wearing it. Although an example of wearable protection equipment 1 is here described for military applications, equivalent wearable equipment 1 may be applied in civil activities.
  • a protection equipment 1 also a proximity protection equipment such as a protective screen or shield, either carried by a user or placed at proximity of a user. In addition to the protection of people, the protection equipment 1 is also usable for protecting non-human parts such as vehicles or parts of vehicles, building or any sensible devices against damaging impacts.
  • the protection equipment 1 of the present disclosure may be made of a monolithic material such as metal or metal alloy, or a homogenous polymer, such as hard polymer or a high performance material such as a ceramic based material.
  • the protection equipment 1 may comprise one or several different monolithic materials arranged on layers.
  • the protection equipment 1 may comprise or be made of a multi-component material such as a mixture of monolithic materials spread or included in one another, a composite material such as those based on a matrix and a reinforcement material.
  • the protection equipment 1 can comprise or be made of ceramic fibres, carbon fibres, or glass fibres, which can be mixed with synthetic polymers of various type.
  • the protection equipment 1 may also comprise a combination of several of the above-mentioned materials.
  • the protection equipment 1 being for human protection, its performance should be certified. It is also necessary to well know the degree of performance of such devices so as to be able to replace it when necessary. It is in addition advantageous to regularly test the protection equipment to anticipate the moment where it will be no longer under predefined performance criteria. By this way, the replacement of the equipment can be planned in advance.
  • the method according to the present disclosure allows to identify defects on or into the protection equipment 1 that can drastically influence their degree of performance.
  • the method of the present disclosure further allows to rate the degree of performance or loss of performance of the protection equipment. Based on the test method, the obtained result can help to decide on whether the protection equipment should be kept or replaced. An instantaneous "yes” or "no" decision can thus be taken.
  • the method according to the present invention allows to evaluate the remaining life time or the aging status of the equipment, based on the determined degree of performance.
  • the method of the present disclosure allows in addition to categorise the protection according to predefined status and decide on the further treatment. For example, a tested protection equipment can be given one of the status ; “to be destroyed”, “perform a complementary test”, “to be repaired”, “to be exchanged” etc.
  • the method of the present disclosure further allows to characterize the defect when identified.
  • the location of a given defect on the protection equipment may be determined.
  • the location includes the position with regard to the surface of the protection equipment so that a central defect can be considered more relevant than a peripheric defect, for example.
  • the location of a defect may also include its position in the depth of the protection equipment.
  • a defect which affects several layers of the protection equipment could then be considered more serious than a defect limited to one layer or a limited number of layers or a fraction of the thickness of the protection equipment.
  • the nature of the defect may also be identified.
  • the method according to the present disclosure comprises a positioning step a) of placing the protection equipment 1 on a bearing or a support 2.
  • the support 2 may be made of hard material such as a hard polymer or metallic plate or other equivalent support.
  • the support 2 may be a flat horizontal plate on which the protection equipment 1 can be placed. Alternatively, the support 2 can be specific to the equipment 1 to be tested.
  • the shape of the support 2 can be for example complementary to the shape of the equipment 1 to be tested.
  • the support 2 is a set of socles on which can be placed the protection equipment 1.
  • Such a set of socles may comprise 3 or more positioning points on which can be placed the protection equipment 1 to be tested.
  • the support 2 may have additional elements such as clamping means or fixation means, where necessary.
  • the support 2 is preferably horizontal or substantially horizontal so that the protection equipment 1 can be merely placed on it without need of any specific fixation.
  • the support comprises at least one adjustable element so as to be adapted to various sizes and or geometries of a wearable protection equipment.
  • the socles when present can be adjusted accordingly.
  • the support 2 may optionally comprise a dumping layer 21 on its positioning surface.
  • the dumping layer 21 separates the equipment 1 to be tested from the support 2 on which it is positioned. By this way, the vibrations of the equipment 1 are not transmitted to the support 2 while remaining free to propagate through the protection equipment 1.
  • the damping layer 21 can be for example a soft polymer, rubber, a foam or any equivalent damping material.
  • the damping layer 21 contributes to make the present method robust and reliable.
  • the protection equipment 1 can be merely placed on the damping layer 21 without specific positioning operations, thus rendering the present method straightforward, robust and easy to implement.
  • the damping layer 21 thus avoids induced vibrations or interfering vibrations and any negative vibrational interaction.
  • the damping layer 21, when present may comprise one or several recess or cavities, or any other type of internal space allowing to lodge at least one microphone 4.
  • Such cavities are preferably open toward the protection equipment 1 to be tested.
  • the microphone 4 arranged within such an internal space is surrounded by the damping layer 21 and phonically isolated from the environment.
  • the opening of the internal space being directed toward the protection equipment allows to receive the sound from the vibrating protection equipment 1.
  • the cavity of the damping layer 21 may be arranged at a central position with regard to the support 2 and/or the damping layer 21. Alternatively or in addition, a recess can be provide close to an end of the damping layer 21 .
  • a microphone 4 can be designed to be displaceable from one recess or cavity of such a damping layer 21 so as to allow the sound record at different positions.
  • several microphones 4 are included in several recesses of the damping layer 21. They can be activated simultaneously during a testing operation or sequentially, so as to record several different profiles.
  • a microphone 4 is combined or directly included in the support 2, said support 2 may be adapted to receive one microphone 4 at different locations of the support 2.
  • one microphone can be incorporated to each socle of the support if present.
  • the support 2 can comprise one or more adjustable bearing (not represented) adapted to receive a microphone 4. Such bearing can thus be displaced at different location of the support 2 so as to allow the sound record at different positions.
  • Such arrangement is particularly suitable to adapt the testing device to various sizes and/or geometries of tested equipment 1. It is further convenient to better identify one or more of the position and the nature of defects.
  • the support 2 can have smaller dimensions than the protection equipment 1 to be tested so that the protection equipment 1, once placed on the support 2, has still free parts which are not in contact with the support 2. The free parts are thus free to vibrate independently from the support 2.
  • the dimensions of the support 2 are however preferably independent from those of the protection equipment 1.
  • a given support 2 may be used for different types of protection equipment 1 having different sizes.
  • the positioning step a) may thus merely consist on placing the protection equipment 1 on the support 2, comprising or not a damping layer 21, without specific positioning adjustments.
  • An adjusting step may be necessary in case one or more adjusting element of the support 2 needs to be better adapted to the size and/or geometry of the tested protection equipment 1.
  • the method according to the present disclosure comprises a percussion step b) of shocking the protection equipment 1 to be tested.
  • the shock is a mechanical shock provided on the surface of the protection equipment 1. It is preferably a single mechanical shock provided with a hard percussion tool 3 acting as a hammer.
  • the shock provided to the protection equipment 1 generates a vibration through its bulk structure.
  • the protection equipment 1 thus vibrates according to its proper vibration modes, which depend on its composition, its internal structure, its shape, its dimensions including its thickness, its mass, its hardness and other properties. In case of a multi-layer or composite equipment, several natural vibrational modes can appear and interfere with one another.
  • the percussion step b) may be performed manually using a dedicated percussion tool 3.
  • the shock may be provided by a percussion tool integrated, associated or combined to the support 2 in an automatic manner.
  • a remote piloting means 6 such as a computer or control unit may be used.
  • An actuator 31 is activated to move the percussion tool 3 against the protection equipment 1 to be tested.
  • the shock is thus given at a predetermined force, a predetermine velocity with a predetermine impulse.
  • the piloting means 6 allows such a reproducible percussion.
  • One or more percussion parameters may be fixed or variable.
  • the force of the percussion can be adapted to the characteristics of the protection equipment 1 to be tested, to the setting of the microphone 4 which collects the resulting vibrations, or to any other surrounding feature.
  • the actuator 31 may be a controllable actuator allowing a precise management of the shock parameters. It can be for example a linear electrical motor.
  • the percussion tool 3 may be made of a metal or a metal alloy. Alternatively, the percussion tool 3 can be made of a synthetic polymer such as a plastic. The characteristics of the shock can thus be adapted in particular by selecting a percussion tool 3 having a specific hardness.
  • one percussion tool 3 is necessary, it does not exclude that two or more percussion tools 3 are provided and arranged at different places so that the protection equipment 1 can be shocked at different places of its surface, once it is placed on the support 2. It is thus possible to compare the vibrational behaviour of the protection equipment 1 with regard to the shocking position. It is understood that when two or more percussion tools 3 are available, they can be activated sequentially. It is also understood that where needed, simultaneous shocks can be provided. It is furthermore clear that the positioning of the percussion tool 3 is adaptable according to the needs and that the shock may be provided at a central position of the protection equipment 1. Providing shocks at different locations and/or of different nature can help better defining the type of defect, if any and/or their seriousness.
  • the protection equipment to be tested 1 is a bullet protection plate placed on a support 2 and the shock is provided at one of its free end, or close to its free end.
  • the method according of the present disclosure comprises a collecting step c) of collecting the vibrations of the protection equipment 1 to be tested, resulting from the mechanical shock.
  • the vibrations are preferably collected at a distance from the vibrating equipment 1 by a microphone 4. In other words, there is no direct contact between the io vibrating equipment 1 and the device used for collecting the vibrations.
  • the microphone 4 can be placed at a distance of less than around 1 cm or less than around 0.5 cm from the surface of the protection equipment 1.
  • a microphone 4 is arranged in a cavity of the damping layer 21. The microphone 4 is then just below the surface of the protection equipment and phonically isolated from any surrounding disturbing noise. Alternatively, a microphone 4 can be placed inside a part of the support 2, near the protection equipment to be tested.
  • the microphone 4 is adapted to collect the vibrations of at least one natural vibrational mode of the protection equipment 1. It preferably collects several vibrational modes of the protection equipment 1.
  • the microphone 4 may be adapted to collect the vibrations in a predetermined range of frequencies. This allows to avoid noise resulting from non-relevant surrounding sounds or vibrations.
  • the predetermined range of frequencies are preferably calibrated to correspond to at least one of the natural vibrational modes of the protection equipment 1.
  • the microphone 4 is preferably monodirectional so that only, or substantially only, the vibration emanating from the protection equipment are collected.
  • the collecting step c) may use a set of several microphones 4 either identical or different.
  • the location of the microphones 4 with respect to the protection equipment 1 can be predefined or adaptable.
  • Several microphones 4 may be placed at different locations around the protection equipment 1 in such a way that the vibrations are collected simultaneously at several locations of the protection equipment 1.
  • each one can be arranged to collect the vibrations within a specific range of frequencies and/or amplitudes so that a precise measurement can be performed on a large range of frequencies and/or amplitudes.
  • Such a configuration helps to analyse complex acoustic responses, in particular in case of non-homogenous materials such as multicomponents or composite materials.
  • the microphones 4 may lodged in several recesses corresponding to different collecting positions under the surface of the protection equipment 1.
  • the natural vibrational modes of the protection equipment 1 correspond to specific frequencies.
  • a first natural vibrational mode may have a frequency of around 950 Hz
  • a second natural vibrational mode may have a frequency of around 1230 Hz. It is possible that the protection equipment 1 has more than two natural vibrational modes.
  • a third natural vibrational mode may have a frequency of around 1880 Hz and a fourth natural vibrational mode may have a frequency of around 2250 Hz.
  • the amplitude of each natural vibrational mode may differ from each other for a given recording position.
  • a first principal natural vibrational mode may have strong amplitude while secondary natural vibrational modes are less strong.
  • the natural vibrational modes denotes the free vibrational frequencies of the tested object and exclude any external frequencies applied to the object.
  • the frequencies of the natural vibration of the protection equipment are preferably comprised between 500 Hz and 3000 Hz, preferably between 800 Hz to 2500 Hz. Depending on the nature of the tested equipment, the frequency range can be different.
  • the microphone 4, or a set of several microphones 4 has enough sensibility to collect the sound resulting from the vibrations of the equipment 1 corresponding to at least one, preferably two, three or four natural vibrational modes. It is in addition adapted to collect the damping of the vibrations along the time of collecting the vibrations.
  • the microphone 4 is preferably placed closed to a surface of the protection equipment 1 which remains free to vibrate, in particular to a surface which is not in direct contact with the support 2. Furthermore, the position of the microphone 4 is preferably chosen to correspond to the most appropriate amplitude of the vibrational modes under investigation. Regarding the relative position of the percussion tool 3 and the microphone 4 or the set of microphones 4, the microphone 4 can be placed close to the percussion tool 3. Alternatively, the microphone 4 is placed remote the percussion tool 3, for example opposite the percussion tool 3 with respect to the support 2 so that the vibrations are collected at an opposite end of the protection equipment under test. The microphone 4 may be independent or combined or associated to the support 2.
  • the number and the relative arrangement of the percussion tools 3 and the microphones 4 can be adapted according to the needs.
  • one or more of the percussion tool or the percussion tools, and the microphone or the microphones are easily removable and displaceable so as to allow the best flexibility of the measurements.
  • one percussion tool 3 and one microphone 4 can be fixed at predetermined positions and one or more additional percussion tool 3 or additional microphones 4 can be removably arranged in a way to adapt their position.
  • Such adaptable arrangement allows analysis of complex materials, in particular composite materials and/or multi-layered materials.
  • the modulation of the relative position of the percussion tools 3 and/or the microphones 4 allows to test objects having different sizes, different shapes, and/or different geometries.
  • the present testing device is well adapted for the testing of helmets or protection shields, or any other wearable protection device, having various sizes.
  • the modulation of the relative position of the percussion tools 3 and/or the microphones 4 offers improved means to determine the location and/or the nature of an identified defect.
  • the microphone 4 may be calibrated to collect the vibrations in a certain amplitude range so that saturation or other negative effects are avoided. Other characteristics of the microphone 4 may be object of specific settings, depending on the needs.
  • the method according to the present disclosure comprises a recording step d) of computing and recording at least one of the frequencies and amplitudes of the natural vibrations of the protection equipment 1 after the mechanical shock provided in the percussion step b).
  • the recording step d) results in a profile showing the natural vibrational modes of the protection equipment 1 as peak frequencies visible in a frequency response function.
  • Figure 1d shows an example of a profile recorded according to the present method. The position of the peaks of the recorded profile corresponds to the frequencies of several natural vibrational modes of the equipment 1. The height of each peak determines the strength of these natural vibrational modes at the corresponding recording position. Strong vibrations result in a high peak whereas weak natural vibrational modes results in the smallest peaks, for a given recording position.
  • the width W of the peaks (figure 2a, 2b) is also a relevant parameter of the profile. It is related to the damping of the corresponding vibrational mode (i.e. a higher damping will result in a wider peak).
  • the damping constant is estimated based on the analysis of the recorded signal in the time and frequency domains.
  • the present method may comprise a step of modifying the relative position of several microphones 4, or the relative positions of several percussion tools 3 or the relative positions of one or more percussion tools 3 with one or more microphones 4.
  • This step can be included just before the percussion step b) so as to better adapt the testing operation to the size and the geometry of the tested equipment.
  • the relative positions of the microphones and/or percussion tools can be modified so as to better sense one or more of the position, the nature, and the location of the defects.
  • the relative position of the microphone and/or percussion tools can alternatively or in addition be adapted just before iterated microphone calibration steps g).
  • One skilled in the art can easily adapt the order and the number of iteration of each of the present steps of the testing method according to the needs.
  • the profile is computed based on frequencies of the collected signal in the collecting step c) and the damping shape of the collected signals.
  • the damping of a given signal can be estimated using the time decay of the corresponding vibration amplitude. Alternatively or in addition, the damping can be estimated based on the width of the corresponding frequency peak.
  • a control unit 7 comprising computational means can receive the signal collected by the microphone 4, or a set of several microphones 4, during the collecting step c) and treat the signal so that a profile can be determined.
  • the recording step d) can comprise one or more additional sub steps of treatment such as filtering some frequencies, independently enhancing or reducing certain signals, homogenizing signals, auto-calibrating signals and so on.
  • the profile resulting from the recording step d) can be shown on a screen 8 or any other displaying means. It can in addition be recorded in a database 9.
  • the recording step d) or the collecting step c) may comprise an active noise cancellation step.
  • the method according to the present disclosure further comprises an analysing step e) of analysing the computed profile obtained by the recording step c).
  • Figures 2a and 2b shows examples of two profiles, the first one corresponding to an acceptable protection equipment 1, the second one corresponding to a non-acceptable protection equipment 1.
  • the analysis comprises determining the mean of the frequency response function T as one of the criteria to characterize the condition of the protection equipment.
  • the analysing step e) comprises the computing of the results from several recording steps c) wherein the relative position of the percussion tool or percussion tools with a microphone 4 or several microphones 4 is modified, so that the nature of a given defect or the location of a given defect with regard to the surface of the tested protection equipment or with regard to the thickness of the tested protection equipment, is determined.
  • the method of the present disclosure further comprises a classification step f) of determining the degree of performances of the protection equipment 1.
  • the classification step f) allows for example to identify or suspect the presence of at least one internal defect such as a crack, or a peeling in case of a laminated material, or other type or categories of defects.
  • the classification step f) allows to determine whether the performance of the protection equipment are still acceptable or whether they correspond to a predetermined quality criteria or not.
  • the classification step f) allows a direct assessment based on the measurement results. It can for example be based on the profile obtained and visually provided on a display or on another viewing support. The operator can assess the degree of performance of the protection equipment 1 directly based on the quality of the profile obtained in the recording step. Such a human evaluation may be considered too intuitive or subject to variations and non-reproducibility. It however remains a reliable means to assess the degree of performance on the field. The user may decide by himself whether the protection equipment can be used or replaced, or placed aside for further investigations.
  • a quality indication can be computed and provided to the user to help him on classify the tested protection equipment 1 .
  • the quality can thus be estimated on a percentage scale or on a scale of few values representing one or more of a "very good", “good”, “acceptable”, and “bad” status.
  • a coloured signal can be provided such as a green signal for acceptable protection equipment, a red signal for non-acceptable protection equipment and optionally an orange signal for questionable results.
  • Other visual indications can be envisaged based on the measurement results.
  • Some predetermined parameters can be used to decide on whether the quality of the protection equipment is acceptable or not. For example, the width W of the peaks of the profile or of some predetermined peaks of the profile, can be compared to an absolute threshold value. The protection equipment 1 can be considered acceptable if the value of the width W is lower than such a threshold value, and refused in case it is higher. For example, other parameters of the profile such as the noise, the number of peaks and so on, can help assessing the condition of the tested equipment
  • each peak, or shift of one or more peaks, or appearance of non-desirable peaks beside the natural vibrational frequencies can also be interpreted as negative records and can result to discard the protection equipment 1. Corroboration of several parameters of a given profile can thus help to determine the reliability of the measurement. It can in addition help identifying discrepancies in some parameters.
  • the classification step f) may thus be based on such an absolute analysis of a given profile.
  • the classification step f) can operate a comparative study of the recorded profile with reference to the collected values of a database 9. For example, one or more of the above mentioned parameters, including the width W of the peaks, their number, position, height, or symmetry can be compared to the average corresponding value stored in the database 9. Alternatively, some reference data, such as a reference profile, corresponding to an acceptable protection equipment 1 can be stored in the database as a model. The value of each analysed parameter may be compared to the corresponding value of the reference profile to determine whether the protection equipment 1 is acceptable or not. Following this comparative analysis, a relative classification step f) is provided.
  • the classification step f) may thus comprise either an absolute analysis of each profile or a relative analysis of a given profile with regard to reference data or a combination of a relative and absolute analysis.
  • the classification step f), whether it is absolute or relative, allows to choose between keeping or discarding the protection equipment 1. It can alternatively or in addition determine a degree of failure or degradation of the protection equipment.
  • the resistance performances of the equipment, deduced from the profile can be ranked on a predetermined scale, based on the value of one or more parameters of the profile. For example, a profile can be considered as partly degraded while still corresponding to the acceptable standard. To this end a given profile may be compared to data comprising series of profiles of known age. One or several parameters of the profiles may be considered. The age of a given profile will correspond to the age of the most similar profile of the database.
  • One skilled in the art understands, that other comparative method can be applied to determine the degree of aging and performances of a given protection equipment 1.
  • the method according to the present disclosure can in addition comprise a microphone calibration step g) wherein the accuracy and sensibility of the microphone 4 is determined and corrected. The frequencies and the amplitudes of the measured signals is then accurate.
  • the microphone calibration step g) also applies to a set of several microphones 4.
  • the microphone calibration step g) can be a separate step. Alternatively, an autocalibration of the microphone 4 can be performed.
  • the present method can in addition comprise a shock calibration step h) wherein one or more of the velocity, the force and the impulse of the shock is determined and corrected.
  • the shock calibration can be performed with a shock calibrator 10 specifically dedicated.
  • the percussion calibration step h) may include repetitive or iterative percussions for statistical evaluation. It may also rely on percussion responses of several protection equipment of the same type.
  • the present method may include a material calibration step i) allowing to calibrate the percussion and the collection of the vibrations according to the properties of the protection equipment 1.
  • the percussion step b) and the collecting step c) may be performed several times to check the behaviour of the protection equipment after a mechanical choc.
  • the percussion step b) may be performed with less or more force, with a less or more hard percussion tool 3 so as to generate different vibrations in the protection equipment 1.
  • the vibrations provided in response may be collected on a large frequency range to identify the frequencies corresponding to the natural vibrational modes of the protection equipment 1. This step allows to rapidly adapt the testing method to any material, independently on its composition, size, shape, hardness and any other of its characteristics. It is even not necessary to precisely know in which type of material it is made.
  • the material calibration step i) is done, the entire measurement process can be initiated.
  • the method of the present disclosure may include reiterating at least once the percussion step b), the collection step c) and the recording step d) to provide at least a second measurement and a second profile of a given protection equipment 1. Reiteration of each of these steps can be performed under identical conditions such that identical profile should be obtained. The resulting profiles can then be compared to each other or merged to provide an average profile resulting from several measurement operations.
  • the iteration of the percussion step b), the collection step c) and the recording step d) can be performed with different parameters.
  • one or more of the force, the velocity, the impulse of the shock or the hardness of the percussion tool 3 can vary from one to the second percussion step b).
  • the shocks may be provided at different positions.
  • the setting of the microphone 4 can be adapted accordingly to properly collect the resulting natural vibrations.
  • the position of the microphone 4 can be object of several iterative tests. In order to facilitate the calibration of the collection step, several microphones may be simultaneously used to determine the best position at which the resulting vibration can be collected.
  • the resulting profile can differ when modulating some parameters.
  • the method can include to test a given protection equipment 1 under several predetermined conditions with different sets of parameters. This thus defines a test protocol adapted to the protection equipment 1 .
  • Such a test protocol may be object of an official and approved protocol.
  • the method can comprise an additional step of cumulating the measurements of several protection equipment 1 of a given type, such as for example several bullet protection plates. Average parameters can thus be determined and be used as reference profile. The probability of the distribution of the peaks can also be determined for each natural vibrational mode. A database of few hundreds profile measurements may be enough to statistically determine acceptable and/or non-acceptable values of parameters. Larger databases can be fed with the cumulated measurement results so that artificial intelligence algorithm may be developed to better determine the characteristics of the protection equipment. Such large number of results can also be used for autocalibration operations or autocorrection of discrepancies.
  • a large database of results may also help identify the nature of the defects, whether it is an impact, a fracture, a delamination, natural aging, or any other defect. It furthermore allows to rank the relevance of the defect according to its nature and determine a scale of importance of the defect when classifying the tested protection equipment.
  • results obtained according to the present method can be combined or compared to results obtained by other methods such as X-ray technology.
  • the microphone 4 or the set of several microphones 4 allows to collect the sound at distance from the protection equipment 1, this does not exclude to use in addition other sensors in contact of the tested equipment, such as an accelerometer or equivalent sensor. Simultaneous measurements can thus be performed. Other measurement techniques such as a laser sensor may also be used simultaneously with the present method. It is then possible to collect more information in a small timeframe.
  • the present method includes the management of the protection equipment 1 of a unit.
  • Each protection equipment 1 of a given unit can be regularly tested according to one or more of the steps a) to i) above described.
  • the frequency of the test may be for example each year or twice a year.
  • the protection equipment 1 may be tested before or after each intervention of the unit so that non-acceptable protection equipment are immediately discarded or quarantined.
  • a given protection equipment 1 may be referenced in a database so that all of its measurement results are stored together. The aging of a given protection equipment 1 may be thus followed. Once its performances are no longer sufficient or when it becomes defective, an alert can be provided after the measurement operations to incite the user to double check or discard and replace it. An indication can be physically provided on each measured protection equipment 1, indicating for example whether the protection equipment 1 is usable or not. A green or red sticked can be used for example, so that it is immediately visible from any user. Alternatively, a machine readable sticker such as a RFID, can be used. The corresponding information may be stored in the database and sent to a remote data center. A replacement can also be automatically ordered once the protection equipment 1 is disqualified or at a given point of aging.
  • each protection equipment 1 may be object of a first test measurement according to the present method so that its specific vibrational characteristics are stored in a database.
  • a corresponding reference can be generated to precisely identify a given protection equipment and associate it the recorded vibrational characteristics.
  • Such a reference can be a number, a QR code or any other readable reference placed on or integrated to the protection equipment 1.
  • the initial state of a given protection equipment can thus be determined as well as its vibrational characteristics.
  • Such a first measurement can be performed at the moment of buying or receiving the equipment at the unit for the first time.
  • An individual follow up can be performed, by comparing the successive measurement of a given protection equipment along its life.
  • Such a management of the protection equipment allows to guaranty on site and at any moment the correct status of a given protection equipment. It further allows saving time and cost related to the testing operations. According to a specific embodiment, quality tests at reception of new protection equipment can easily be performed directly on site
  • the management of the protection equipment 1 as described can be integrated to a more general and centralized management system allowing for example to combine the results of the vibrational measurements with more detailed investigations such as X-ray measurement or other investigation methods.
  • the management method can include several acoustic tests on site on regular basis, before sending the protection equipment to a centralized test laboratory. Combined and statistical results can help to precisely categorize a given protection equipment at a given point of time. It allows to select different outcomes such as "to be destroyed”, “perform a complementary test”, “to be repaired”, “to be exchanged” etc....The protection equipment can thus be dispatched on appropriate site depending on their status.
  • the present disclosure also covers a testing device 11 adapted to implement the above described method. It comprises a support 2 on which a protection equipment 1 can be positioned. The support 2 can be either unique or removably replaced by a different support 2 so that different protection equipment can be tested.
  • the testing device 11 further comprising at least one percussion tool 3 adapted to shock a protection equipment under test.
  • the percussion tool 3 is activated by an actuator 31, piloted with a pilot mean 6.
  • the pilot means may take the appearance of a personal computer with human machine interfaces such as keyboard, display, or any known interfaces.
  • the testing device 11 also comprises at least one microphone 4 adapted to collect the natural vibrational modes of a protection equipment 1. It comprises computing means to generate a profile based on the collected vibrations.
  • the testing device 11 can be connected to a remote database 9 or comprise such a database 9 storing the measuring results from past measurements.
  • the testing device 11 further comprises an executing program allowing to determine the parameters of the measurements, the parameters for the classification and any other necessary parameters
  • the testing device 11 is preferably portative so that it can be easily used at or near the operation place.
  • the testing device 11 further comprises a shock protection such as a rigid suitcase or housing.
  • the rigid suitcase advantageously comprises a phonic isolation such that the test method can be performed even in noisy environments.
  • the testing device 11 can be arranged in a rigid suitcase 12 having a lid, which can be closed while allowing the measuring operations according to the present method.
  • the rigid suitcase is waterproof so that electronic and digital equipment of the testing device 11 is safely arranged.
  • the testing device 11 is preferably autonomous. To this end, it may comprise a battery.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Testing Of Devices, Machine Parts, Or Other Structures Thereof (AREA)
  • Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)

Abstract

La présente invention se rapporte à un procédé de test d'un équipement de protection (1) en matériau composite. Le procédé comprend une étape b) de percussion de choc de l'équipement de protection (1) à l'aide d'un outil de percussion mécanique (3). Les vibrations naturelles sont collectées et le profil de réponse résultant est ensuite analysé afin de déterminer si l'équipement de protection correspond ou non à des normes de performance prédéterminées. La présente invention couvre en outre un procédé de gestion de l'équipement de protection d'une unité et un dispositif de test portable (11) permettant de mettre en œuvre facilement le procédé au niveau ou à proximité de la salle d'opération.
PCT/IB2021/061011 2020-12-04 2021-11-26 Procédé de test d'équipement de protection WO2022118154A1 (fr)

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CH01538/20A CH718128A1 (fr) 2020-12-04 2020-12-04 Procédé et dispositif de test pour équipements de protection.
CH01538/20 2020-12-04

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107462319A (zh) * 2017-09-15 2017-12-12 安徽理工大学 一种小型电机噪声的声学识别处理方法及实验装置
CN107907206A (zh) * 2017-11-15 2018-04-13 大连交通大学 一种固有频率在线检测系统
CN111693388A (zh) * 2020-07-09 2020-09-22 北京汽车集团越野车有限公司 一种可变的力激励装置

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107462319A (zh) * 2017-09-15 2017-12-12 安徽理工大学 一种小型电机噪声的声学识别处理方法及实验装置
CN107907206A (zh) * 2017-11-15 2018-04-13 大连交通大学 一种固有频率在线检测系统
CN111693388A (zh) * 2020-07-09 2020-09-22 北京汽车集团越野车有限公司 一种可变的力激励装置

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EP4256287A1 (fr) 2023-10-11

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