DE2737747A1 - MEASURING METHOD AND DEVICE FOR THE ELEMENTATION CONDITION OF A PART - Google Patents

Description

The invention relates to a method and a device for measuring the fatigue state of a mechanical part, such as a component of an aircraft.

It is known that in aircraft components which are exposed to considerable stresses in flight, certain components are more prone to breakage than others and that the designer generally has a m.iximal number of flight hours in advance which the aircraft must not exceed without this component being replaced. This number of flying hours is often determined by an approximate estimate of the repeated stresses this constituent will experience during Flights is suspended, with a sufficient surcharge to eliminate any risk.

The inventor has determined that it would be beneficial to the aircraft, a device to accommodate, which is in the 'location, s perform a state measurement of the actual fatigue state of the mechanical part, so that this mechanical part can be replaced when it such an amount several times, was exposed to stresses by the risk of fracture has become more flights at too great.

It is therefore the object of the invention to specify a method and a device for measuring the fatigue state of a mechanical part which can be carried out or accommodated on board an aircraft.

According to the invention, a measuring device for the fatigue-dungaauatand tinea mechanical Telia is specified, which has a measuring element for the deformations of the parts (a strain gauge) which is connected to a comparator for comparing the measurement result with a predetermined threshold value and which has a counter to count the

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Number of times the specified threshold was exceeded having.

DdS method according to the invention is that counted \. This shows how often the part has been subjected to stress when a deformation has exceeded a given threshold value, the number obtained being an estimate or determination of the fatigue state of the part.

In this way, this part is only replaced when it has actually been used for a long enough time and it has become too dangerous to continue using it, and no longer dependent on the number of flight hours that more or less randomly determined.

According to the invention, in particular the exceedance of several selected threshold values is counted in order to both to take into account a large number of violations of a relatively low threshold value as well as a small number of violations of a high threshold value, with noticeable fatigue occurring in both cases.

For this purpose, the device according to the invention contains a comparator with several threshold values and a counter for the exceedances of each threshold value.

In the latter case, the determination of the state of fatigue can be done by several numbers that represent the counting results for each threshold are, or by a · number, the one The integration of the totality of the results represents, for example, a great suame with each chosen Coefficients for each of the results. Am weighted The summing element is connected to the meter on the output side.

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To avoid being exceeded several times of a given threshold value is counted when the exerted load oscillates slightly around this threshold value, it is provided that the comparisons are carried out with a hysteresis in such a way that two exceedances of one given threshold value would only be recorded in the associated counter if the deformation measurement is a has passed through a waiteren threshold value between these two exceedances, a so-called trigger threshold value, the vou. given threshold is different.

Each stress threshold, its exceedance are to be determined, therefore has in practice two clearly separated threshold values, namely a lower threshold value and an upper threshold value, both of which are compared with the measurement signal. Exceeding the upper threshold triggers a count of one Exceeding from if there has been confirmation of this exceeding at least beforehand as a result of the signal falling below the lower threshold value.

The comparisons with all threshold values can be carried out in both analog and digital ways. If the comparison is made analogously, so many can Comparisons * how threshold values are provided and the results of the comparisons * are connected to counters or the various threshold values can also be fed one after the other to a single comparator by suitable multiplexing.

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These two solution principles are also for digital signals applicable, the latter being preferable.

The invention therefore provides a measuring method and a device for the state of fatigue of a mechanical part, the device having a measuring element for deformations of the part, which is connected to a comparator for comparing the measurement results with various predetermined ones Threshold values, as well as a counter, for counting the number of times the various predetermined ones have been exceeded Thresholds, where the count represents an estimate of the fatigue condition of the part, where a comparison with a hysteresis characteristic is thus carried out is that the exceeding of a given threshold value is only recorded in the counter when the measurement the deformation has exceeded a triggering threshold value different from the given threshold value before or after another exceeding the given threshold. The invention is for the measurement of the fatigue state of Aircraft parts can be used both on the ground and in the air.

The invention will be explained in more detail with reference to the embodiments shown in the drawing. Show it:

1 shows a block diagram of an exemplary embodiment the invention,

Fig. 2 shows the waveform of an electrical

Signals to determine if thresholds are exceeded before they are counted demonstrate,

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Fi? ·. 3 schematically shows a detailed circuit diagram of the exemplary embodiment in FIG. 1.

In Fig. 1, the principle of the invention is shown schematically. Extensometers 10a, 10b ... are on or on several parts 20 of an aircraft attached and emit measurement signals that after amplification and subsequent Filtering in amplifiers 30a, 30b ... are multiplexed in a multiplexer and then converted into digital signals are in an analog / digital converter 50.

The resulting digital signals are in a comparator arrangement 60 with various selected stress threshold values compared in a desired gradation, which is stored in an addressable digital value memory, briefly threshold value memory 7Q are written in such a way that the measurement signals are compared one after the other with each threshold value. The addressing of the threshold memory 70 is synchronously controlled by a synchronizing system or a logic 80.

Each stress threshold value corresponds to a low or lower digital threshold value and a upper or high digital threshold to ensure that the given stress threshold is exceeded then to record when the measurement signal exceeds an upper threshold value after it has fallen below a lower threshold value dropped 1st.

The comparator arrangement 60 compares the digital measurement property of each of the successive threshold values and the comparator result is used further in the following ways

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For each group consisting of the lower and upper thresholds if a lower threshold value is exceeded initially nothing; if an upper threshold value is exceeded, this excess is recorded in an excess memory 90 and the number or number of the exceeded threshold is recorded in a threshold number memory 100, if at least this overshoot has taken place after the measurement signal has fallen below the corresponding lower threshold value, the latter by means of a second Exceeding memory 110 is effected for the exceeding of the previous threshold value. If against it the previous lower threshold was already exceeded, this will be seen as merely a signal fluctuation or fluctuation is considered between the lower and the upper threshold and finds no count of the stress being exceeded for this threshold group.

For this purpose, only the second excess memory 110 is connected to the first excess memory 90 in such a way that it can be determined whether the threshold value was exceeded or not exceeded during the previous sample or measurement. The exceedances of the stress threshold values are sequentially recorded in the eraten exceedance memory 90 at addresses which correspond to those of the threshold value memory in the form of the logic signals "O" and "1 ^W , the logic" 1 "indicating that a Exceeding the upper threshold value has taken place, and a logical "0" indicates that the signal has fallen below the corresponding lower threshold value, this ⁿ 0 "being used to confirm or validate the recording of the possible threshold value violations in the following comparisons.

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A logic system 120 determines the conditions for reading or writing into the threshold number memory 100 and also writes in the first excess memory 90 the "0 ^M and" 1 ^W , which indicate the exceeding of the threshold value, in accordance with the Results of each threshold value comparison and according to the content of the second excess memory 110 for the exceeding of the previous threshold value.

FIG. 2 explains the principle of exceeding the threshold value with the aid of a time diagram of the measurement signal.

The amplitude of the analog measurement signal is shown as a function of time. Of course, the comparisons can with the threshold values both analog and digital after converting the measurement signal into a digital signal as in accordance with Fig. 1 take place.

In FIG. 2, three stress Sdiwave values S ₁ , Sp, S, are shown, each of which is based on an upper threshold value Sh ₁ Sh ₂ or Sh. and a lower threshold value Sb ₁ , Sb ₂ and Sb, respectively, are formed, the lower threshold value having a somewhat lower absolute value or magnitude than the upper threshold value. In the exemplary embodiment, the first stress threshold value S _{1 is} shown as negative (for example compressive stress instead of tensile stress).

In the example shown, the measurement signal initially crosses or exceeds the lower threshold value Sb ₂ .

As long as the upper threshold value Sh _{2 is} not exceeded, the number "0" written into the first excess memory 90 is at the address corresponding to _{the numbers of this threshold value Sh 2} , Sb ₂ , the second threshold value S _2.

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If the upper threshold value Sh _{2 is} exceeded, when comparing the signal with the threshold value, a number "1" is written into the first exceedance memory 90, and the number of the exceeded threshold value (here 2) or its address in the addressing of the Threshold memory 70 is written into threshold number memory 100. B _e i of the next sample or measurement is this "1" also has contributed to the second Uber underflow memory 1io.

If the signal falls below the upper threshold value Sh ₂ again, but remains above the lower threshold value Sb ₂ , the content of the first exceedance memory 90 is _{not changed at the address of the second threshold value S 2} and is not written into the threshold number memory 100 . The "1" written in the second exceedance memory 110 is used to inhibit or suppress such writing and zv / ar as long as the signal _{remains above the lower threshold value Sb 2} even if it exceeds the upper threshold value Sh ₂ v / ieder.

If the signal falls below the lower threshold value Sb ₂ in the following comparator sequence, the logic system 120 enables an ⁿ 0 ^{M to be written} into the first overrun memory 90, WOdUiCh the record of the overrun of the upper threshold value is deleted and this first overrun memory 90 is reset again for a possible further counting of the exceedance of the respective threshold value.

In the following comparison, the second excess ^{memory 110 contains this 11} O ″ and the logic system 120 is no longer inhibited or locked with regard to recording the excess in the threshold number memory 100.

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The successive overruns are recorded sequentially in the form of their address numbers in the threshold number memory 100 recorded. A counter 130 increments each time the address of the threshold memory 100 in which the following information is recorded.

The one in rig. 2, the number corresponding to the threshold value S ₂ is written into the threshold value memory twice in succession, namely a first time at time A and a second time at time B, but not at time C, since the signal is between times B. and C had not dropped below the lower threshold Sb _2.

Of course, what has been said for the second threshold value S ₂ also applies to all other threshold values, taking into account that the synchronization logic 80 performs the sequential comparison of the measurement signal emitted by the converter 50 with one of the threshold values (alternating upper threshold values and lower threshold values) included in the threshold value -Memory 70 are included, thereby controls that sequential addressing of this threshold value memory 70 is carried out.

What is true of one Messaeig also applies to all others, those of the different strain gauges 10a, 10b ... and grouped by the multiplexer 40 on an analysis line. It it should be noted that those written in the threshold value memory 70 Values of the threshold values are not necessarily the same for the different multiplexes and that hence the threshold store 70 has a number of values

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must contain, dxt, - equal to the number of threshold values (Mie total of the upper and lower thresholds) multiplied by the number of Zwed ^ is. This information can be determined or processed in various ways. For example, an upper threshold and a lower threshold for a branch, then the upper threshold and the lower threshold value of the same number of the following branch or also an upper threshold value and a lower threshold word tine branch, then the following upper threshold and the lower threshold of the same branch. The multiplying frequency is of course synchronized according to the selected sequence of addressing, i.e. that accordingly all Threshold values of one branch, then those of the other branch are addressed or that the corresponding threshold values of all branches and then the following thresholds of all pointers, etc., are addressed.

the

The synchronizing system or * synchronizing logic 80 therefore controls not only the addressing sequence of the memories 70 and 90 but also the multiplexing as well as the rest to be synchronized Components of the device according to the invention, in particular the analog / digital converter 50.

In Fig. 3 is a detailed circuit diagram of a erfindungsgeuiaßen Device according to the block diagram according to FIG.

Ks are shown a strain gauge 10a to which an amplifier 302 and a filter circuit 304 are connected downstream, the output of which is connected to the input of a multiplexer 40, the other Input branches are not shown, but their type are identical to the first. The multiplexer 40 is also Here, for example, a multiplexer with four branches whose cultiplexing control is periodic based on a logical one

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Synchronization system or a synchronization logic 80 takes place, which is shown on the upper part of the circuit diagram according to FIG.

The synchronizing logic 80 controls the operational sequence of the entire Device according to the invention based on a clock signal generator or a clock 802 of frequency F. By division obtained sub-multiples of this frequency F control the various phases and, in particular, in the case of FIG. 3, the multiplexing is carried out at a frequency of F / 1024, although this choice is not absolutely necessary, as explained will be.

The multiplexer 40 is followed by an analog / digital converter 502, which is controlled by the synchronization logic 80 so that that it successively converts the multiplexed measurement signals of the four input branches or paths, the control frequency this converter is 502 F / 256.

The converter 502 is an 8-bit plus a sign bit converter, since Yes thresholds are exceeded both negative as well as positive kind should be counted. This converter 502 is followed by an absolute value arithmetic element 504, that is merely a binary number complement formation circuit, as is usually the case after analog / digital converters is used.

, Ia \ r that which is the measurement signal, which will be compared with the different stress thresholds in a digital manner and gemültiplexter at the output of the absolute value calculating member 504 exists.

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This signal is a first line or a first i.Lngi.nj a comparator 60 supplied, the other Lengths digital values of the stress threshold values received, the excesses of which are to be counted. These values of the threshold values are in one of their digital values ; rte storing threshold value memory 70 is written or saved. The threshold value memory 70 storing digital values is a programmable read-only memory (PROM). It is adressierbpr via addressing inputs that are connected to the synchronization logic 80, which has a sequential Addressing achieved to from the output of the threshold memory 70 to the comparator 60 the digital values of the successively stored stress threshold values to feed.

In the exemplary embodiment, the threshold value memory contains 16 stress threshold values for each measurement branch ¹ . In particular, as explained with reference to FIGS. 1 and 2, each stress threshold value is subdivided into an upper threshold value or actual threshold value of the measurement and an associated lower threshold value or trigger threshold word. The threshold value memory 70 therefore contains a number of values of the threshold values, which is 32, multiplied by the number of input branches, namely 128 values with 7 bits each. When addressing the threshold value memory 70, the values of the upper threshold value and the threshold value below * α are alternated and, if the multiplication is carried out with a frequency of F / 1024 as stated, the addressing is carried out in such a way that initially all of the first branch assigned Threshold values, then assigned to the second branch, etc., are checked. However, an addressing of a given threshold value of a branch,

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then a threshold value of the same order of precedence for ν? in another branch etc. must be performed, however Of course, the multiplexing then takes place on different levels Wise done in such a way that at a given multiplexing instant at the comparator or on the comparators incoming digital signal is compared with a threshold value, which is a moment corresponding branch is assigned. In the latter case, the multiplexing frequency is then rather

Each stress threshold is by its address in the threshold memory. This address is • A threshold number or number in the sequence of yours On drawing, supplemented by a bit that indicates whether it is associated with the respective threshold value upper threshold or lower threshold.

The synchronization logic 80 successively supplies the threshold value numbers or numbers which propagate at a frequency F / 16, as well as a bit of the frequency F / 8 for the distinction between upper and lower threshold values. The threshold values, but not the additional bit of the frequency F / 8, are also applied to addressing inputs of a first threshold value excess memory 90, which is provided for recording the excesses of each threshold value by the measurement signal, that is to say that a binary number ⁿ 1 ⁿ is written to the memory location corresponding to a threshold number for a given measurement branch if the measurement signal compared with this threshold value indicates an excess, and that a "0" is written to this memory location if the

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Signal indicates that there is no overshoot, and this always taking into account the as stated introduced hysteresis by the presence of an upper threshold and a lower threshold for each Stress threshold value, namely an excess written into the first excess area 90 if the measurement signal is above the upper threshold value, this writing or storage is deleted becomes when the measurement signal is below the lower threshold value, and w ^ bui that in the exceedance memory at a given Threshold value address written binary number is not changed if the measuring signal is between the respective upper Threshold and lower threshold remain.

The excess memory 90 therefore has 64 individually addressable binary digits corresponding to 16 threshold values for each of the four branches or paths.

A logic system 120 has a number of logic gates and is between the comparator 60 and the control input for writing into the excess memory connected and achieves the functions explained below.

Ea U * i monitors the content of an auxiliary memory or second excess memory 110, which is provided at the output of the first excess memory 90, at the same time as it is the output of the signal corresponding to the test of a certain stress threshold value from the Receives comparator output. The second excess memory 110 contains a display there at this point in time the information previously written into the first exceedance memory 90 at the address of the given threshold value:

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If the measurement signal is less than the lower threshold value, there is an "O" in the first excess memory written via the logic system 120 immediately after the comparison with the lower threshold value;

if the measurement signal is below the tested or monitored upper threshold value, no entry is made in the excess memory 90 by logic system 120 triggered in such a way that its content is not changed and that this content during the subsequent check or monitoring of the same threshold value is found again,

if the measurement signal is above the upper threshold value, but the second excess memory 110 has a "1" (i.e. the threshold value has already been exceeded in the previous measurement) no enrollment is made in the Moment of comparison with the upper threshold causes, whereby the content of the memory is not changed will;

if the measurement signal is above the upper threshold value in the comparison with the upper threshold value and if the second excess memory 110 contains a "0 ^H , the logic system 120 issues the write command to write a ¹ M" into the first threshold value exceeded Memory in the address corresponding to the exceeded value.

In the latter case, the logic system 120 also provides for the writing of the address or, more precisely, the number or number of the just exceeded the threshold value into a memory

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the · grievances or numbers of the exceeded values or Threshold number memory 100 by the fact that this memory 100 is supplied with a write command that is constantly receives information at its binary inputs which contains the address of the stress threshold value that has just been checked including the number of the branch or path to which it relates, but without the bit that indicates whether it is an upper or lower threshold.

This way every time a threshold is exceeded is, the number or number of this threshold value and the branch to which it relates to the threshold number memory 100 enrolled. The addressing of this threshold number memory 100 is in progress. The logic system 120 increases the address in each case by one unit, to which cKfe information of the following exceeded threshold value must be enrolled immediately after enrollment has ended.

In this way, at the end of a series of measurements of the threshold number memory contains 100 in a series of successive A4r * esenplätzen the numbers of all exceeded stress-5 ^c h * »elle values together with the numbers or numbers of the branches, on which they relate As a result, of exceeding these thresholds. This memory 100 is recovered or evaluated, for example at the end of the flight of an aircraft, if the examination of the fatigue state of an aircraft part is concerned, and the counts of the threshold values exceeded can be evaluated.

In this case, the sequence of writing into the memory 100, which is given by the logic system 120, is achieved by means of of a constant timer 1202 (approx. 100 ms, since the write-in

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zfcit in the memory 100 is relatively long) and inhibited or £> p <-iTt a blocking signal to the clock 802 during this time interrupt the measurements during this enrollment time. On the other hand, this clock blocking signal is used to count up a counter 130 is used, the outputs of which form the addressing signals of the Speie ers 100 and to be written to each Exceeded must be incremented or increased.

As a threshold number memory 100 for several aircraft Can be used, an initial entry is provided in the first address space of the number of the aircraft. This takes place at the same time as the measurement is initialized or triggered by a strong pulse generated by a Circuit 1206 is output. The starting address (address in the threshold number memory 100) is marked by a decoder 120Π, which is provided at the output of the comparator 13G is.

When the counter 130 is zero, it is the number of the aircraft hence the first written information, followed by (Jen numbers or numbers of the successive exceeded Thresholds.

In addition, it is provided that the measurements on the aircraft can be carried out both in flight and on the ground, however, the values of the stress thresholds are not necessarily the same. Only certain values of threshold values contained in the threshold value store 70 are used, which is why an additional bit is used for each value of the threshold value written or contained in the threshold value memory is provided to indicate whether it

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is a threshold that applies to an aircraft in flight or on the ground.

A manual switch 1210 selects via an AND element 1212 the threshold values of interest, depending on whether the aircraft is on the ground or in the air. He locks the recording of other exceedances. This manual switch 1210 can, for example, extend or retract of the chassis.

Furthermore, a marking device is provided to mark which of the memory locations of the threshold number memory 100, in which the information of the exceeded threshold values is written, with the other places are empty so that when the aircraft is changed or when another series of measurements is carried out, the system inscribes the numbers or numbers of the exceeded Threshold values can continue at still empty places and a deletion of the previous registrations avoided will.

"Le last bit of information in each memory systematically ever written a" 1 "at every enrollment of Crillen such" Dasu is that hien at this bit position binary 2 £ "1" are enrolled in all previously used addresses while in unused addresses Binary numbers ¹¹ O "are written in. This bit is used as the filling level L / fc of the memory in order to control an address computer system which enables the counter 130 to be automatically reset to the first address that has not yet been used Register 132 is supplied for successive etching, which this investigation carries out with a ££ *) *> ellen control frequency F / 4 in that the parallel outputs of all memory cells of the register 132

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are connected to parallel binary inputs of the counter 130 for successive estimation.

A command input of the address calculator of the consecutive estimation register 132 writes a binary number "1" in the register 132. A clock input signal of frequency F / 4 triggers this writing and possibly triggers the transfer of this binary number to the output of register 132, which corresponds to the most important position or the most important memory location of counter 130, depending on whether the new one occurs on line 1214 Bit is a "1" or a "0". This operating mode is repeated: The writing of a new bit "1 ^n" in the register 132, the triggering and, if necessary, the transmission of the following weighting bit to the following weighting point of the counter 130 according to the new bit that occurs on the line 1214. At the end of the transmission sequence for all bits of the counter 130, the address appearing at the output of the counter 130 is the address of the last already occupied position of the memory 100. The following position is free and this will then receive the following information.

A preferred embodiment of the invention has been explained in which the recording and the comparison are based on digital waves takes place. Analog processing can also be carried out in which the analog values of the above Thresholds and lower thresholds in different glazers can be compared. If the measuring voltage has an upper When the threshold value is reached, the corresponding comparator controls a monostable multivibrator which, by means of a bistable multivibrator, establishes the connection between another comparator, the the measuring signal bit has compared the corresponding low threshold value and another monostable multivibrator

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manufactures. The latter controls a counter of the consecutive If this threshold value is exceeded, it also controls the resetting of the bistable oscillation.

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Claims (1)

DIPL-PHYS. WOLi GANG SEEGER PATt :. ! LAWYER? 7? 77A7 THIERSCHSTR. 27 D-8 MUNICH 22 TEL. (O89) 22 51 52 Telegram (Cable Address): Seegerpateni iunchen TbIux: S 24487 patopd Attorney's certificate: 44 p _a t 2 1) Societe de Fabrication d'Instruments de Mesure SFIM 13, avenue Ramolfo-Garnier, 91301 Massy, France 2) J.P.B. S.a.r.l., 11, Ru> i Laperouse, 78390 Bois d'Arcy, France Method and apparatus for measuring the fatigue state of a part Claims 1. / Device for measuring the fatigue state of a mechanical part, characterized by a measuring device for measuring the deformations of the part which is connected to a comparator for comparing the measurement result with a predetermined threshold value, and a counter for counting the number of times the predetermined threshold value has been exceeded, the counter ciöbnis an estimate of the fatigue s to st and es des Partly represents. 809813/0708 POSTS «. MECK ACCOUNT MUNICH 188888-807 · DRESDNER BANK MUNICH, ACCOUNT NUMBER 7 7O8OO5 . Heßvorrichlung according to claim 1, characterized in that that the comparator compares the measurement result of the deformations with several threshold values and that a counter connected to the output of the comparator counts the exceedance of each threshold value, where the total of the counted results represent an estimate of the fatigue condition of the part. :. HulBvorri rect n <- h claim 1 or 2, characterized in that both positive and negative threshold values are provided. μ. Mc-ß device according to one of claims 1 to 3, characterized characterized in that the comparator is designed with a hysteresis curve so that a predetermined threshold value in the counter can only be recorded is when the measurement of the deformation has a triggering threshold that differs from the given Si t, wave value exceeded before or after the given threshold value was exceeded again. ': · .. ripping device according to claim h, characterized in that the recording of an exceedance of the given threshold value in the counter for counting the excesses takes place when the absolute value of the measurement of the deformations reaches the value of the predetermined threshold value after the value of the triggering threshold value has previously been reached has been :. Must device according to claim 5 »characterized in that that the measurement signal successively with a series of values of measurement threshold values and a series of Values of triggering thresholds is compared, the 809813/0708 I-wave value memory (70) are included, which is sequentially addressable and which is connected to the input of the comparator (SO) . 7. Measuring device according to claim 6, characterized in that the comparator (60) has a logic system (120) is connected to a threshold value excess memory (90) which is analogous to the threshold value memory (70) is addressable on the one hand in this excess memory (90) in a given threshold value appropriate address to write the occurrence of an exceedance of this threshold value and to on the other hand this registration later ..u delete, if the measurement signal has fallen below the triggering threshold value assigned to the given threshold value. 0. measuring device according to claim 7, characterized in that the counting device for counting the exceedances of the threshold value is a threshold number memory (100) connected to the logic system (120) to to write information about the exceeded threshold value, the logic system (120) being so designed is that this enrollment will be disabled if the threshold exceeded memory (90) previously contains a display of the exceeding of the threshold value at the 4th address of the respective threshold value. 9. Measuring device according to claim 8, characterized in that the stored in the threshold number memory (100) Information are the addresses of the threshold values contained in the threshold value memory (VO) and that these Addresses consecutively in the order in which they were exceeded at consecutive addresses 809813/0708 27377A7 of the threshold number memory CiOO) will. 10. Method for measuring the fatigue state of a mechanical Part, characterized, that the deformations of the part are measured and that each time the deformation of the Partly exceeds a predetermined threshold value, the counting result being an estimate of the Represents the fatigue state of the part. 11. Measuring method according to claim 10, characterized in that it is counted every time the deformations of the Sometimes exceed several, each different sowing values, whereby the totality of the counting results is a determination represents the fatigue state of the part. 12. Measuring method according to claim 11, characterized in that, in addition, the Slhlresults for the different Threshold values are added, with each result having a predetermined multiplying coefficient is applied. 809813/0708