FORM 2
THE PATENTS ACT, 1970 (39 of 1970) & THE PATENTS RULES, 2003
COMPLETE SPECIFICATION (See section 10, rule 13)
1. Title of the invention: METHOD FOR DETECTION OF TIRE FAILURE IN
ENDURANCE TEST
2. Applicant(s)
NAME NATIONALITY ADDRESS
CEAT LIMITED Indian CEAT Ltd At: Get Muwala Po: Chandrapura Ta: Halol - 389 350 Dist: Panchmahal, Gujarat, India
3. Preamble to the description
COMPLETE SPECIFICATION
The following specification particularly describes the invention and the manner in which it
is to be performed.

TECHNICAL FIELD
[0001] The present subject matter relates, in general, to testing of a tire to be
installed in a vehicle and, particularly but not exclusively, to a method for detection of tire failure in endurance test using tire vibrations.
BACKGROUND
[0002] Endurance (indoor) tests of tires gives idea about various performance
parameters of tires, such as durability (endurance) at high speed; tyre characteristics / force and moment; rolling resistance; noise levels; tyre stiffness; foot-printing, including dynamic foot-printing; and wheel fatigue and so on. In the indoor tire endurance test, the endurance test may be performed while running the tire on an outer periphery of a drum. During tire endurance test, once the tire fails or bursts, it is not possible to analyze the root cause of failure by physical or visual inspection as the tire will be damaged physically. It is not possible to identify from where the defect might have started propagating to surface of the tire. Hence, it is desirable to stop the endurance test just at the initiation of tire failure, so that it is possible to analyze the root cause of failure by cutting the tire at a specific location. In other words, when a failure starts to occur in the tire, it is desirable to immediately detect the start of the failure and end stop the test.
BRIEF DESCRIPTION OF DRAWINGS
[0003] The detailed description is described with reference to the
accompanying figures. In the figures, the left-most digit(s) of a reference number
identifies the figure in which the reference number first appears. The same numbers
are used throughout the drawings to reference features and components.
[0004] Fig. 1 illustrates a method for detection of tire failure in an endurance
test, in accordance with an implementation of the present subject matter.
[0005] Fig. 2 illustrates components of a system for detection of tire failure, in
accordance with an embodiment of the present subject matter.
[0006] Fig. 3 shows a graph, explaining crest factor, in an example
implementation of the present subject matter.
[0007] Fig 4. shows a method for detection of tire failure, in accordance with
another example implementation of the present subject matter.

DETAILED DESCRIPTION
[0008] The present subject matter relates to aspects relating to detection of tire
failure during endurance tests by using tire vibrations.
[0009] Understanding the performance of tires and tire mechanics is critical in
determining their influence on the ride, handling, and safety of two wheelers, three wheelers, cars & commercial vehicles. This involves a preliminary testing of the tire before it is fitted onto a wheel rim. The tire is conditioned, i.e., pumped up to the required test pressure and brought up to temperature, before being mounted on a test rig for testing at a desired load and speed. The tire is regularly inspected over the course of the test run, after which, if applicable, it is sent for an internal analysis where the tire is not only cut open, but also undergoes X-ray or CT scanning to determine where the tire failed structurally and why.
[0010] Tire testing and assessment services often include tests for rolling
resistance, energy efficiency, rolling noise and road performance (e.g. braking, handling) on various surface conditions. Performance testing of a tire is carried out mainly by a wheel endurance (high load) and a wheel high speed performance test. Endurance test is carried out by freely rotating the tire on a smooth surface metal wheel or drum at a fixed speed, increasing load stepwise to certain kilometer limit or till failure. In high-speed test, tire is rotated on a drum or wheel at a step wise increasing speed at constant load, holding for a fixed period at every speed step, till failure occurs or to a maximum speed limit.
[0011] Conventionally, during endurance testing of tire, the tire is rotated by
driving it on the drum. For detecting an anomaly/failure of the rotating tire in the tire endurance test, a vibration sensor is installed at a location where the failure is likely to occur. The sensor is generally attached to an inner side of a tire tread band. The vibrations of the tire where the sensor is mounted on the tire, may then be measured by the sensor/accelerometer rotating with the tire. This limits the reading collated during the endurance testing to be specific to the portion of the tire where the sensor is mounted. Reading pertaining to other portions of the tire are either ignored or need installation of multiple sensors corresponding to the other portions.

[0012] Further, in the conventional setup, the failure of the tire is mainly
considered to be a failure by detecting a change in unevenness of the outer surface by various methods and detecting a tire failure based on the detected change in the unevenness of the outer surface. The unevenness in the outer surface of the tire may be a sign of premature tire wear, thereby increasing the risk of tire leaks or tire burst, yet, with the conventional method of detecting change in unevenness of tire surface, the exact point of initiation of tire failure may not be known and it may be difficult to identify exactly the point of time when tire failure is probably intended to occur. Moreover, the tire wear pattern needs to be examined regularly to assess the durability of tire, in that the tire testing may take considerable time in failure analysis of tire.
[0013] In some other conventionally known methods, tire failure may be
determined when at least one of a predetermined amount of local distortion and cracking occurs on the tire surface. This type of failure can only be confirmed by visual inspection of the test tire by the operator periodically interrupting the test, and as a result, it cannot be detected promptly when a crack occurs, avoiding a decrease in detection accuracy for the crack failure.
[0014] In some other conventional contact type methods and systems for
determining a condition of a tire and/or wheel assembly, wear conditions of different portions of the tire are compared with each other, to determine whether the tire has uneven wear, and whether the tire has been operated over-inflated or under-inflated. The under-inflated tires tend to overheat, causing tread separation, resulting in premature wear and tear or even a full-on tire blowout. The over-inflated tires have too much air contributing the center of tires to be completely worn down. Though, over-inflation and under-inflation of tires indicate risk of damage to tires, determining uneven wear or under-inflation and over-inflation method of testing is a time-consuming procedure and does not accurately predict the failure initiation point of tire such that the tire may burst before the failure analysis of tire is carried out.
[0015] Further, in most conventional set-ups for durability testing of tires,
during the testing, the tire often burst before occurrence of failure is identified and

thus the tire is rendered useless for further inspection to determine the cause of the tire failure. When the tire fails, it is challenging to analyze the root cause of tire failure by visual inspection as the tire is completely damaged. It is difficult to determine where defect may have started propagating to the tire surface. Likewise, endurance tests in which the rolling speed is examined at regular time intervals do not reveal when the burst occurs since the occurrence of tire bursts varies slightly from tire to tire. For these reasons, it is not possible to stop the rolling immediately before the burst of the tire, and to accurately identify the location of the failure of the tire component and investigate the cause of the failure. The present invention addresses the above-mentioned problems by providing a method for detection of tire failure during endurance tests by using tire vibrations. In an embodiment, the method of tire failure detection overcomes the above-described problems associated with the conventional approach wherein the tire burst before the failure occurrence is identified. Further, the method of the present invention also addresses the other problems associated with the conventional methods of tire testing, where the tire failure is detected only when there is some physical deformations in tire, such as bulge and cracks in the tire.
[0016] In accordance with an embodiment of the present subject matter, a
method for detection of tire failure using a tire endurance test machine comprises installing at least one accelerometer sensor at a proximate static location of the tire on the tire endurance test machine. The proximate static location of the tire may be a location on a mounting axle hub of the tire endurance test machine where vibrations can be measured effectively. The vibration of the tire at the mounting axle hub of the tire endurance test machine is measured by the accelerometer sensor. The tire vibrations are generated corresponding to the rotation of the tire on a drum of the tire endurance test machine. Subsequently, a failure initiation point of the tire is identified based on the measured tire vibrations to stop the rotation of the tire prior to occurrence of a tire failure event. The technique as elaborated above, enables identifying a point in time when failure is initiated while the tire undergoes testing in a tire endurance test machine so as to immediately stop the rotation of tire before the tire failure event occurs so as to avoid physical

damage to the tire. This also enables to identify the cause of failure by physical inspection of the tire.
[0017] In an example implementation, the tire vibrations may be measured in
at least one of the radial, tangential and lateral directions. Subsequently, tire vibrations are recorded continuously in at least one of the radial, tangential and lateral direction by a data acquisition system. In an example, measuring vibration of the tire at the mounting axle hub of the tire includes measuring the vibrations of the tire in the tangential direction, wherein the tangential direction is a direction that is tangential to a circumference of the tire. In an embodiment, a data acquisition system may be used to record the measured vibrations of the tire, wherein the data acquisition system collects measured vibrations from the accelerometer sensor and converts the measured vibrations to digital signals readable by a computing system for further analysis.
[0018] The step of identifying the failure initiation point of the tire as
elaborated above further comprises determining rate of change of vibration of the tire. The determination of the rate of change of vibration of the tire includes determining, based on the vibrations, a rate of change of acceleration of the tire. The method further includes assessing a rate of change of crest factor or standard deviation. The crest factor or standard deviation is calculated by comparing the rate of change of acceleration to a predefined threshold value of rate of change of acceleration that may be predefined based on historic experimental data. In an example, the threshold value may vary based on tire size, tire type, constructions and design etc of tire. Determination of rate of change of vibration further includes assessing the rate of change of crest factor by comparing previous value of crest factor for n number of data points with current value of crest factor from n number of data points and representing it in terms of % change and determining if the rate of change of crest factor or standard deviation is higher than the predefined/previous threshold value. The rate of change of vibration using the crest factor that shows increasing values with respect to the standard deviation and crest factor values before failure occurs may indicate a tire failure indication and consequently, the durability test may be stopped.

[0019] Thus, the method of failure detection disclosed in the present invention
facilitates in accurately identifying a failure initiation point during tire endurance testing so as to immediately stop the tire testing to avoid physical damage to the tire. Since physical damage to the tire is prevented, the exact location on the periphery of the tire where the defect might have started propagating to the surface and the root cause of failure can be analyzed by cutting the tire at that specific location.
[0020] Further, in the present set-up for durability or endurance testing, the
vibrations of tire are measured across the entire circumference of the tyre, so that
failure initiation can be identified at any point throughout the periphery of the tire
and the tire testing can be immediately stopped, before the tire bursts.
[0021] The present invention also provides several advantages, such as defect
can be analysed in any part of the tire instead of analysing only the specific part of the tire where sensor is mounted. As the accelerometer is mounted on a static location, only the tire to be tested need to be replaced rather than changing the entire step of a tire testing assembly of the endurance test machine.
[0022] Thus, the method of the present invention enables faster and accurate
sensing of vibrations by the accelerometer, such that the failure can be detected promptly, and the tire testing can be stopped immediately before the tire is completely damaged. Accordingly, there is less chance of damage to machine/environment due to tire burst as well as lower cost of repair and tire development.
[0023] The above and other features, aspects, and advantages of the subject
matter will be better explained with regard to the following description and accompanying figures. It should be noted that the description and figures merely illustrate the principles of the present subject matter along with examples described herein and, should not be construed as a limitation to the present subject matter. It is thus understood that various arrangements may be devised that, although not explicitly described or shown herein, embody the principles of the present disclosure. Moreover, all statements herein reciting principles, aspects, and examples thereof, are intended to encompass equivalents thereof. Further, for the

sake of simplicity, and without limitation, the same numbers are used throughout the drawings to reference like features and components.
[0024] Fig. 1 illustrates a method 100 for detection of tire failure in an
endurance test, in accordance with another implementation of the present subject
matter. Fig. 2 demonstrates a system 200 for detection of tire failure. Fig. 3
illustrates a graph, explaining crest factor calculated during the method for
detection of tire failure, in an example implementation of the present subject
matter. For the sake of ease of explanation, Fig.1, Fig. 2 and Fig.3 are explained in
conjunction with each other. Fig 4. shows a method for detection of tire failure, in
accordance with another example implementation of the present subject matter.
[0025] The order in which method 100 is described is not intended to be
construed as a limitation, and any number of the described method blocks may be combined in any order to implement method 100, or an alternative method. Although, the method 100 may be implemented in a variety of system for detection of tire failure including a tire endurance testing machine, for the ease of explanation, the present description of the example method 100 for detection of tire failure is provided in reference to the system 200 for detection of tire failure as illustrated in Fig. 2 and described later in detail. Thus, it may be understood that blocks of the method 100 may be performed, for example, by the system 200, as illustrated in FIG. 2.
[0026] Referring to Fig. 1, at block 102, the method 100 for detection of tire
failure using tire vibrations, in an implementation of the present subject matter, comprises, placing or installing at least one vibration sensor/accelerometer sensor 205, at a proximate static location of the tire 202 on a tire endurance test machine 201 of the system 200. The vibration sensor may be a piezoelectric sensor that senses vibration. The vibration sensors may be any flexible devices used for measuring vibrations occurring in various processes.
[0027] The vibration sensor relies on the piezoelectric effect while measuring
the changes within acceleration, pressure, temperature, force otherwise strain by changing an electrical charge. Vibration sensors may be generally used for measuring fluctuating accelerations or speeds or for normal vibration

measurement. An accelerometer may be any vibration sensor that is used to
measure the vibration or acceleration in rotating machines, devices or articles.
[0028] The accelerometer may be any piezoelectric or any other type of
accelerometer which is sensitive to vibrations generated by tire during tire
endurance test. In some examples, strain gauges may also be used instead of an
accelerometer for measurement of force. The accelerometer may be any sensor that
measures the dynamic acceleration of a physical device as a voltage. The
accelerometer 205 may be any electromechanical device to measure acceleration
forces. These forces may be static, like the constant force of gravity pulling at your
feet, or they could be dynamic - caused by moving or vibrating the accelerometer.
[0029] The proximate static location to the tire 202 where the accelerometer
sensor 205 is mounted may be any location on a part of a wheel tire assembly or a stand/shaft 204 of tire endurance test machine 201, wherein the stand/shaft 204 is in a fixed or stationary condition and may be connected to a mounting axle hub of the tire endurance test machine 201. The accelerometer sensor 205 may be installed at the proximate static location, from where vibrations of the tire 202 may be measured effectively. Thus, the position of the accelerometer 205 may also be fixed or static and does not need frequent replacement each time a tire 202 is tested. In an example, the accelerometer sensor 205 may be any one of the single-axis accelerometers to measure vibration in at least any one of the lateral, tangential or radial direction. It can also be a dual-axis accelerometer to measure vibration in at least any two of the lateral, tangential or radial directions. It can also be a triaxial accelerometer measuring vibration in all the three lateral, tangential and radial directions. It is normal, that a tire even in its operating condition may have some vibration because of small, minor defects. Therefore, each tire may exhibit a level of vibration that may be regarded as normal or inherent. However, when the tire 202 is rotated on a drum 203 of the tire endurance test machine 201 during tire endurance test, the tire vibration increases or becomes excessive, due to change in stiffness and/ /or geometry because of failure or separation of one or few internal components.

[0030] Accordingly, at block 104, vibrations/accelerations of the tire 202 are
measured at the mounting axle hub of the tire endurance test machine 201 by the
accelerometer sensor 205 as-mentioned above. Lateral acceleration (AL) is
measured in a direction perpendicular to the plane in which the tire rotates.
Tangential acceleration (AT) is measured tangentially to the circumference of the
tire. While, radial acceleration (AR) is measured along a radius of the tire.
[0031] At block 106, the vibrations or accelerations of the tire 202 are recorded
continuously in the tangential 207 direction by a data acquisition system 218 of the system 200. In an example, the vibrations or accelerations of the tire 202 may also be recorded in the radial or lateral direction along with the tangential vibrations. The data acquisition system 218 may typically consist of transducers for converting the vibrations into equivalent electrical signals and measuring the electrical signals. The data acquisition system 218 may also include signal conditioning logic to perform amplification, isolation, and filtering, and other hardware for receiving analog signals and providing them to a processing system, such as a personal computer.
[0032] Alternatively, a data logger may be employed for recording the
vibrations, wherein the data logger may be a self-contained data acquisition system with a built-in processor and pre-defined software embedded therein. The data loggers can run as stand-alone devices and are portable and easy to use for specific tasks. The data loggers have local storage to save data and include SD slots for additional memory. Data Acquisition system also comprises a measurement system and a computer that can measure electrical or physical properties and record them for further analysis. The accelerometer/vibration sensor converts the physical parameter (for example: vibration, acceleration etc.) into a signal which can be measured electrically. The data acquisition system takes in the analog signals from the sensors and converts them to digital signals readable by the computers for further analysis. In an example, the data acquisition system 218 may provide the digital signals or data corresponding to the analog signals obtained from the sensors to a computing system 209 of the system 200. The computing system 209 may further analyze the data for the detection of tire failure.

[0033] Tires allowed to run to failure generally require more extensive repair
than would have been necessary if the problem had been detected and corrected early. Moreover, catastrophic tire failures, such as tire burst can also pose a safety problem for test personnel along with the added cost of repair for the tire can be staggering.
[0034] Therefore, to detect and identify developing problems before tire
failure and extensive damage to tire occurs, the method of the present invention proposes identifying a failure initiation point of tire by measuring rate of change of vibration of the tire including, at block 108, determining based on the vibrations, a rate of change of acceleration of the tire. The rate of change of vibration is calculated at a point when there is an instantaneous variation in the vibration of the tire. The vibration signals may be analyzed in a time domain by calculating the statistical features, such as, crest factor, standard deviation etc. A time domain signal metric may indicate how vibration signal changes over time and therefore, the time domain signal metric may detect imminent failure in the tire allowing the replacement of tire prior to its failure.
[0035] In general, the rate of change of acceleration can be understood as
derivative of acceleration with respect to time and thus, the rate of change of acceleration may also be computed by calculating a standard deviation. Standard deviation is a statistical metric defining the amount of variation in the vibration signal, for instance, the amount of variation in the instantaneous vibration signal with respect to the mean vibration signal. Crest factor may be understood as simply the ratio of the peak acceleration to RMS acceleration of the vibration signal and is used for overall vibration level measurements. This is expressed by the equation C = APEAK ÷ ARMS, (A being the acceleration). As crest factor increases, it tends to be an indicator of bearing failure. The crest factor may also be calculated using the below expression and can be understood more clearly from fig.3:
Crest factor = Peak value of signal /Rms value of signal Peak value of signal- peak value of signal is the maximum value attained by an alternating quantity during one cycle. It is also known as the maximum value or crest value.

Rms value of signal- rms value of signal is the root-mean-square value of a signal. For a digitized signal, it represents the average "power" of a signal.
[0036] Referring to Fig.3, Fig.3 illustrates a graph, explaining crest factor
calculated during the method for detection of tire failure. As shown in Fig. 3, the
line 301 indicates the peak value of acceleration, and the line 302 shows the root
mean square values of the acceleration. The crest factor is a parameter of waveform
calculated as a ratio of peak value to the root mean square value. Essentially, the
crest factor denotes increase in peak values or the ratio of instantaneous peak
amplitude of a vibration signal, to the root mean square RMS value of the vibration
signal. Referring back to Fig.1, the method 100, further includes, at block 110,
assessing a rate of change of crest factor, wherein the rate of change of crest factor
is calculated by comparing the rate of change of acceleration to a predefined
threshold value of acceleration that may be predefined based on historic
experimental data. In an example, the rate of change of acceleration is compared
at different time instances to a predefined threshold value of rate of change of
acceleration that may be predefined based on the historic experimental data.
[0037] In operation, discrete points for different value of rate of change of crest
factor are selected at different times, for example, for rate of change of crest factor
at t=0, 1, 2, 3…n seconds, where t denotes time. Thereafter, rate of change of crest
factor at t=n seconds is compared with a rate of change of crest factor at predefined
value, defined as a default value at t=0 seconds. Consequently, at step 112, if the
rate of change of crest factor at time =n seconds is determined to be higher than
the rate of change of crest factor at predefined value, or t=0 seconds, the rate of
change of vibration using the rate of change of crest factor may signify a tire failure
indication and immediately, the durability or endurance test may be stopped.
[0038] Similarly, if the readings captured by the data logger with respect to the
crest factor/standard deviation indicate corresponding higher values in successive readings over a period of time. These increase in readings captured at the data logger provide an indication that a tire failure may possibly occur and thus the test need to be promptly stopped before the tire burst occurs. Optionally, an alarming means give an alarm by, for example, sounding an alarm or displaying on

displaying means when tire failure initiation point is identified. Alternately, the alarming means may be a software trigger to endurance machine controller to stop the machine. Additional tests and measurements may be taken to further reduce the number of possible causes of a tire failure.
[0039] Further, reference is made to tabular data (shown below) that
demonstrates the analytical results obtained for different types of tires, wherein change of vibration over a period of time was observed for different types and sizes of tires:

# Before Failure Diuina Failure Percentaze rise
Tires Standard Dev. Crest Factor Standard Dev. Crest Factor Standard Dev. Crest Factor
(Tire-1) 0.4 ^ 1 5 150% 67%
ii
(TYRE-2) 0.3 2.6 1.05 16 250% 515%
TYKE-} 0.4 4 1.4 11.6 250% 190%
(tyre-4) 0.253 3.1 0.808 6.47 219% 109%
[0040] The table shows different values of standard deviation and crest factor
for different types of tires and a percentage wise analysis of the standard deviation and the crest factor at 2 different points of time. The data has been captured before the failure occurrence of tire and during the failure occurrence of tire. The data values captured for the standard deviation and crest factor during tire failure has occurred, clearly show increasing values with respect to the standard deviation and crest factor values before failure occurs. It is to be noted that there are high chances of tire failure indication, if the percentage-wise rise in the standard deviation and crest factor is greater than 50%. However, the percentage wise rise in standard deviation and crest factor indicating the tire failure may vary based on tire size, type, design and construction.
[0041] Hence, the method of failure detection of the present invention enables
faster and accurate identification of tire failure, such that the tire testing can be stopped immediately before the tire is damaged. There are several other

advantages, such as, no chances of damage to machine/environment due to tire burst as well as lower cost of repair and tire development.
[0042] Fig 2 depicts a system 200 for detection of tire failure, in accordance
with an implementation of the present subject matter.
[0043] In another embodiment of present subject matter, the system 200
includes a tire endurance test machine 201. The tire endurance test machine 201 may include a shaft 204 that is static and connected to a a mounting axle hub of the tire endurance test machine 201. A tire 202 may be mounted on the mounting axle hub and the tire 202 may be rotatable around the shaft 204 by a drum 203 of a tire endurance test machine 201. An accelerometer sensor 205 may be installed on the proximate static location of the tire 202 on the tire endurance test machine 201. The proximate static location of the tire 202 may be a location on the mounting axle hub of the tire endurance test machine 201 where vibrations of the tire generated corresponding to the rotation of the tire on the drum are to be measured by at least one accelerometer sensor 205 as the drum 203 rotates the tire 202. The vibrations of the tire 202 may alternatively be measured by any vibrations sensors as mentioned above. The vibrations of tire 202 by the accelerometer 205 may be measured in at least any one of the lateral, tangential and radial directions. The vibrations of the tire 202 may be measured in tangential direction, and optionally the vibration in lateral or radial directions may also be measured.
[0044] The Lateral acceleration (AL) 206 is measured in a direction
perpendicular to the plane in which the tire rotates. Tangential acceleration (AT) 207 is measured tangentially to the circumference of the tire. While radial acceleration (AR) 208 is measured along a radius of the tire 202. The acceleration in the direction may then be recorded in a continuous manner at a sample rate higher than 1 Hz using a data acquisition system 218. Sample rate may denote numbers of samples recorded by the sensor in one second. The data acquisition system 218 may be communicatively coupled to the tire endurance test machine 201 to monitor and record the measured vibrations of the tire 202 by the accelerometer sensor 205 installed on the tire endurance test machine 201. The data acquisition system 218 may be any computing device, such as a server, a desktop

computer, laptop, smartphones, or a tablet. The data acquisition system 218 may
comprise one or more processors for executing instructions to fetch and record data
or vibrations as measured by the accelerometer sensor 205. In an example, the
processor may be implemented as microprocessors, microcomputers,
microcontrollers, digital signal processors, central processing units, state
machines, logic circuitries, and/or any devices that manipulate signals based on
operational instructions. The data acquisition system 218 may comprise a memory
for storing the instructions executable by the one or more processor and to store
data or measured vibrations obtained from the accelerometer sensor 205. The
instructions may cause the processor to monitor and record the vibrations as
measured by the accelerometer sensor. The instructions may also cause the
processor to convert the measured vibrations or analog signals as obtained from
the accelerometer sensor to digital signals readable by a computing system 209 of
the system 200 for further analysis. The memory may include any computer-
readable medium known in the art including, for example, volatile memory (e.g.,
RAM), and/or non-volatile memory (e.g., EPROM, flash memory, etc.). The
memory may also be an external memory unit, such as a flash drive, a compact
disk drive, an external hard disk drive, or the like. The typical data
acquisition system may have multiple channels of signal conditioning circuitry which provide an interface between external sensors and the A/D (analog to digital) conversion subsystem. Data logger may either interface with a computer and use software to view and analyze the collected data or may be used as a stand-alone device with a local interface or connect wirelessly to a device. Alternatively, the data logger may operate independently of a computer, unlike many other types of data acquisition devices.
[0045] The system 200 may further include a computing system 209
communicatively coupled to the tire endurance test machine 201 to identify a failure initiation point of the tire 202 based on the measured tire vibrations to stop the rotation of the tire 202 prior to occurrence of a tire failure event. That is, the computing system 209 may be configured to predict bursting of the tire 202 based on the data or measured vibrations collected from the accelerometer 205. The

computing system 209 may be any computing device, such as a server, a desktop computer, laptop, smartphones, or a tablet. The computing system 209 may comprise one or more processors for executing instructions to identify a failure initiation point of the tire 202 on a tire endurance test machine 201. In an example, the processor may be implemented as microprocessors, microcomputers, microcontrollers, digital signal processors, central processing units, state machines, logic circuitries, and/or any devices that manipulate signals based on operational instructions. The computing system 209 may comprise a memory for storing the instructions executable by the one or more processor. The instructions may cause the processor to identify a failure initiation point of the tire 202 during a tire endurance test on the tire endurance test machine 201. The memory may include any computer-readable medium known in the art including, for example, volatile memory (e.g., RAM), and/or non-volatile memory (e.g., EPROM, flash memory, etc.). The memory may also be an external memory unit, such as a flash drive, a compact disk drive, an external hard disk drive, or the like.
[0046] The tire endurance test machine 201, the computing system 209 and/or
the data acquisition system 218 may be connected over a network for the purpose of detection of tire failure.
[0047] In an example, the network may be a single network or a combination
of multiple networks and may use a variety of different communication protocols. The network may be a wireless or a wired network, or a combination thereof. Examples of such individual networks include, but are not limited to, Global System for Mobile Communication (GSM) network, Universal Mobile Telecommunications System (UMTS) network, Personal Communications Service (PCS) network, Time Division Multiple Access (TDMA) network, Code Division Multiple Access (CDMA) network, Next Generation Network (NON), Public Switched Telephone Network (PSTN). Depending on the technology, the network includes various network entities, such as, gateways, routers; however, such details have been omitted for sake of brevity of the present description.
[0048] In an example, the computing system 209 may comprise module(s).
The modules may be coupled to the one or more processor of the computing system

209. The module(s) may include routines, programs, objects, components, data structures, and the like, which perform particular tasks when executed by the processor or implement particular abstract data types. In an example, the processor may be implemented as microprocessors, microcomputers, microcontrollers, digital signal processors, central processing units, state machines, logic circuitries, and/or any devices that manipulate signals based on operational instructions. The module (s) includes modules that implement certain functionalities of the computing system 209 such as, a data logging module, a data analysis module, a crest factor and standard deviation computation module and a prediction module. as elaborated with respect to Fig 1. The module(s) may further include modules that supplement applications on the computing system, for example, modules of an operating system.
[0049] The date logging module 210 may receive data related to measured
vibrations of the tire 202 from at least one of the data acquisition system 218 and the accelerometer sensor 205 installed on the tire endurance test machine 201. The data logging module 210 may monitor and record tire vibrations measured by the accelerometer sensor 205. In an example, the data logging module 210 may include the functionality of the data acquisition system 218. For instance, the data logging module 210 may collect measured vibrations from the accelerometer sensor 205 and convert the measured vibrations to digital signals readable by the computing system 209 for further analysis. A data analysis module 212 may further be configured to determine a rate of change of acceleration based on the measured tire vibrations. In an example, the data analysis module 212 may be configured for the analysis of the digital signals related to the measured vibrations for the determination of the rate of change in acceleration using various mathematical and statistical calculations, a detailed description of the method of data analysis in already provided with reference to Fig. 1. Additionally, the crest factor and standard deviation computation module 214, calculates a rate of change of crest factor by comparing the rate of change of acceleration to a predefined threshold value of rate of change of acceleration that may be predefined based on historic experimental data as explained in reference to Fig. 1.

[0050] The prediction module 216 predicts occurrence of bursting of the
tire/wheel by identifying a failure initiation point of the tire 202 based on the determination that the rate of change of crest factor or standard deviation is higher than the predefined threshold value. The modules of the computing system 209 as discussed above may be used in an end-to-end fashion using various open-source machine learning models.
[0051] Based on the identification of the failure initiation point, tire endurance
test may be stopped without causing any damage to the tire 202 and the tire 202 may be inspected to identify the cause of tire failure.
[0052] Fig. 4 illustrates a method 400 for detection of tire failure, in
accordance with another example implementation of the present subject matter. The order in which the method 400 is described is not intended to be construed as a limitation, and any number of the described method blocks may be combined in any order to implement method 400, or an alternative method. Although, the method 400 may be implemented in a variety of system for detection of tire failure including a tire endurance testing machine 201, for the ease of explanation, the present description of the example method 400 for detection of tire failure is provided in reference to the above-described system 200 for detection of tire failure as illustrated in Fig. 2. Thus, it may be understood that blocks of the method 400 may be performed, for example, by the system 200, as illustrated in FIG. 2. The method for detection of tire failure can be more clearly understood with reference to Fig 4. The method is initiated at block 401 and proceed to block 402. At block 402, initially, a number of samples (i.e., acceleration values) or data from the accelerometer 205 of the tire endurance test machine 201 of the system 200, at time, t=0 to t=n seconds may be collected by the acquisition system of the system 200 or the data logging module 210 of the computing system of the system 200. Thereafter, the rate of change of acceleration may be calculated by the data analysis module 212 of the computing system 209 as a derivative of acceleration with respect to time at block 403. The rate of change of acceleration may be computed by calculating a standard deviation and a crest factor. The crest factor may be calculated for the samples collected for the duration t=0 to t=n seconds by the crest

factor and standard deviation computation module 214 of the computing system 209 of the system 200. Then the next value of crest factor may be calculated for t=n seconds to t=2n seconds, where t denotes time in seconds. At block 404, % (percentage) difference in these two crest factors, i.e., the difference in crest factor of t=n to t=2n seconds and crest factor of t=0 to t=n seconds may be calculated by the crest factor and standard deviation computation module 214.
[0053] For example, Number of samples (acceleration values) collected for
time t=0 to t=n seconds is m Peak value of acceleration in this duration is �����

[0054] This process repeats for the next t=0 to t=n, Number of samples
collected for time t=n to t=2n seconds is m. % rise in standard deviation or crest factor may be calculated as given below. % rise in standard deviation =

[0055] Having calculated the % rise in the standard deviation or crest factor, at
block 405, the previous value of crest factor for n number of data points is obtained and at block 406 the previous value of crest factor is compared with current value of crest factor for n number of data points as already elaborated with ref to Fig. 1 and Fig. 2.

[0056] Further, at block, 406, a determination is made whether the percentage
rise is greater than a threshold value. In case the determination is in the affirmative, the method proceeds to block 407, to determine if there is any change in load or a change in speed as per tire endurances test. On the other hand, if it is determined, at block 406, that the percentage rise is not greater than a threshold value, the method proceeds back to block 402. As mentioned above, at block 407, determination as to change in load or change is speed is made. To determine the same, at block 408, load with time stamp is received. During load change or speed change, the rate of change of crest factor or standard deviation does not show a high percentage rise as these changes are progressive & not sudden. Thus, if the determination at block 407, indicate that there is no change in load or speed and there is a sudden change in the tire vibrations, the crest factor will indicate a sudden increase in peak values further indicate tire failure initiation & the test may be stopped on the tire endurances test machine at block 409, to avoid high physical damage to tire. Otherwise, if it is determined that the % rise occurred because of substantial change in load or speed at the time of the sample taken, the method proceeds to block 402 and the whole method is repeated for subsequent samples of acceleration.
[0057] Further, as mentioned above with respect to Fig. 1, the threshold value
may vary based on tire size, tire type, constructions and design etc of tire. Rate of change of crest factor may be calculated by comparing previous value of crest factor for n number of data points with current value of crest factor from n number of data points and representing it in terms of % change. If percentage rise in crest factor or standard deviation shows higher values, the test may be immediately stopped.
[0058] Although implementations for method 100 and a system 200 for
detection of tire failure are described, it is to be understood that the present subject matter is not necessarily limited to the specific features of the methods and systems described herein. Rather, the specific features are disclosed as implementations for the method and system for detection of tire failure.

I/We Claim:
1. A method (100) for detection of tire failure, wherein the method comprises:
installing (102), at least one accelerometer sensor (205), at a proximate static
location of the tire (202) on a tire endurance test machine (201), the proximate
static location of the tire (202) being a location on a mounting axle hub of the tire
endurance test machine (201);
measuring (104), vibrations of the tire (202) at the mounting axle hub of tire endurance test machine (201) by the accelerometer sensor (205), wherein the tire vibrations are generated corresponding to the rotation of the tire (202) on a drum (203) of the tire endurance test machine (201); and
identifying a failure initiation point of the tire (202) based on the measured tire vibrations to stop the rotation of the tire (202) prior to occurrence of a tire failure event.
2. The method (100) as claimed in claim 1, wherein identifying the failure
initiation point of the tire (202) further comprises determining (108) rate of change
of vibration of the tire (202).
3. The method as claimed in claim 2, wherein determining (108) rate of
change of vibration of the tire (202) comprises:
determining, based on the vibrations, a rate of change of acceleration of the tire (202);
assessing (110) a rate of change of crest factor or standard deviation, the crest factor or standard deviation calculated by comparing the rate of change of acceleration to a predefined threshold value of rate of change of acceleration that is predefined based on historic experimental data;
wherein assessing the rate of change of crest factor includes comparing previous value of crest factor for n number of data points with current value of crest factor from n number of data points and representing it in terms of % change; and determining if the rate of change of crest factor or standard deviation is higher than the predefined threshold value.

4. The method (100) as claimed in claim 1, wherein measuring vibration of the tire (202) at the mounting axle hub of the tire (202) includes measuring the vibrations of the tire in tangential direction, wherein the tangential direction is a direction that is tangential to the circumference of the tire (202).
5. The method (100) as claimed in claim 1, wherein the method comprises recording (106) the measured vibrations of the tire by a data acquisition system (218), wherein the data acquisition system (218) collects data from the accelerometer sensor (205) and converts them to digital signals readable by a computing system (209) for further analysis.
6. The method (100) as claimed in claim 1, wherein the rate of change of vibration is determined at a point when there is an instantaneous variation in the vibration of the tire (202).
7. A system (200) for detection of tire failure, the system (200)
comprising:
a tire endurance test machine (201) having a shaft (204) that is static and connected to a mounting axle hub of the tire endurance test machine (201), wherein a tire (202) is mounted on the mounting axle hub and the tire (202) is rotatable around the shaft (204) by a drum (203) of the tire endurance test machine (201);
at least one accelerometer sensor (205) installed at a proximate static location of the tire (202) on the tire endurance test machine (201) , the proximate static location of the tire (202) being a location on the mounting axle hub of the tire endurance test machine (201) where vibrations of the tire (202) generated corresponding to the rotation of the tire on the drum are to be measured by the at least one accelerometer sensor as the drum (203) rotates the tire (202), wherein

a computing system (209) communicatively coupled to the tire endurance test machine (201), wherein the computing system (209) is to identify a failure initiation point of the tire (202) based on the measured tire vibrations to stop the rotation of the tire (202) prior to occurrence of a tire failure event.
8. The system (200) as claimed in claim 7, wherein the system (200) further
includes:
a data acquisition system (218) to record the measured vibrations of the tire (202), wherein the data acquisition system (218) collects measured vibrations from the accelerometer sensor (205) and converts the measured vibrations to digital signals readable by the computing system (209) for further analysis.
9. The system (200) as claimed in claim 7, wherein the computing
system (209) further comprise module(s) that implement functionalities of the
system (200), wherein the module(s) include:
a data logging module (210) that receives the measured vibrations of the tire (202) from at least one of the data acquisition system (218) and the accelerometer sensor (205);
a data analysis module (212) configured to determine a rate of change of acceleration based on the measured tire vibrations;
a crest factor and standard deviation computation module (214) to: assess a rate of change of crest factor or standard deviation, the crest factor or standard deviation being calculated by comparing the rate of change of acceleration of the tire (202) to a predefined threshold value of acceleration that is predefined based on historic experimental data, wherein assessing the rate of change of crest factor includes comparing previous value of crest factor for n number of data points with current value of crest factor from n number of data points and representing it in terms of % change; and

determine if the rate of change of crest factor or standard deviation is higher than the predefined threshold value;
a prediction module (216) to identify a failure initiation point of the tire (202) based on the determination that the rate of change of crest factor or standard deviation is higher than the predefined threshold value.