# Method for estimating reliability and safety of product on basis of non-destructive control

FIELD: non-destructive control.

SUBSTANCE: method includes determining critical size χ_{cr} of defects in operation mode and allowed size [χ]_{d.o.} of defects. Control results are presented in form of bar graph in coordinates (N_{det},χ), where N_{det} - number of detected defects, χ - characteristic size of defect. Probability of defect detection P_{pd} is determined, as well as source defectiveness N_{sc}=frequency(χ), remaining defectiveness N_{rm}=φ(χ) as difference between N_{sc} and N_{det}. Remaining defectiveness is divided by trustworthy portion χ≤χ_{d} and probability portion χ>χ_{d}, where χ_{d} - size of defects at limit between trustworthy and probable portions. On basis of probable portion of remaining defectiveness probability of existence of defects is determined, sizes of which exceed χ_{cr} and defects, sizes of which exceed [χ]_{d.o.}. Safety of product is determined as probability of absence of defects, sizes of which exceed χ_{cr}, and reliability of product is determined as probability of absence of defects, size of which exceed [χ]_{d.o.}.

EFFECT: higher efficiency.

9 cl, 5 dwg

The invention relates to the field of nondestructive testing (hereafter NC) discontinuities, irregularities and other defects of material products or groups of products (parts, elements and the like), including ultrasonic, eddy current, radiography and other NDT methods. The invention can be used in nuclear and conventional power generation, transport, aviation, shipbuilding, petrochemical, oil, gas and product pipelines, agricultural machines and other areas of technology and engineering.

In accordance with existing rules and regulations in the technique sets the allowed sizes of the discontinuities, the excess of which is prohibited. Such discontinuities are called defects. Defects in the case of detection by nondestructive methods will be repaired by the repair.

It is believed that after carrying out non-destructive testing and repair on its results of all identified defects in the product there are no defects. It is considered that the reliability and safety of the product in use is provided (see, for example, normative documents in the field of nuclear energy: "rules of arrangement and safe operation of equipment and pipelines of nuclear power installations" PNEG-7-008-89, Equipment and pipelines of nuclear power installations. Welded joints and welding. Profilecontrol" PNEG-7-010-89, Gosatomnadzor, Energoatomizdat, 1991).

Actually currently in the technique virtually no methods and means of nondestructive testing, guaranteed, with 100%accuracy of detecting all defects. Therefore, there is always a certain probability of missing defects, including defects that pose a danger (i.e., the development of which during operation will result in damage to the product or its destruction). It is known (for example, Gurvich, A. "Reliability of flaw detection control as the reliability of the system "Flaw - operator - environment, Inspection, 1992, No. 3, pp.5-13)that in almost all cases, NC there is a significant probability of missing a defect larger sizes significantly larger than the allowable size. In practice, it is almost always after NC and resolve identified defects in the product is still defective. These remaining defects ultimately determine the reliability and performance of the product.

Existing methods for assessing the reliability of product based on formal mathematical approaches that do not reflect the real remaining in the product defects. For example, in the framework of existing theories of reliability of the actual level of reliability determined by the results of mathematical processing of the so-called stream the failures of similar products, in operation Strakowski VA "Operation of nuclear power plants", Moscow, Energoatomizdat, 1999, section 3.5: "Methods of analysis of discontinuities of nuclear power plants equipment"). The drawback of such approaches is that in operation of the product should be damaged or destroyed, before you can assess the actual level of reliability and security.

The technical result, which directed this invention is that it allows assessment of the real defects of the product after inspection and repair identified defects and to determine the actual level of reliability and safety of the product before it will be destroyed or damaged in the operation.

The technical result is achieved in that in the method of determining the reliability and security products, including the identification of defects in products using non-destructive testing and repair product control, characterized in that determines for a particular product or group m the same products critical dimensions χ_{kr}defects in the operation mode and the valid operation dimensions [χ]_{de}defects, the inspection results are in the form of a histogram in the coordinates (N_{OBN}that χ), where N_{OBN}- the number of detected during the inspection of defects, χ - x is acteristically defect size,
moreover, when testing the same products inspection results summarize and present in a single histogram, determine the probability of defect detection P_{water}determine the original defect N_{Ref}=f(χ), determine the residual defect N_{ocm}=ϕ(χ) as the difference of N_{Ref}and N_{OBN}residual defects are divided into significant part χ≤χ_{d}and probabilistic part χ>χ_{d}where χ - the characteristic defect size χ_{d}- the size of the defects at the boundary between true and probabilistic parts defined:

where χ_{max}- maximum size of defects in this product;

for the probabilistic part of the residual defects determine the reliability of the product N as the probability of the absence in the product discontinuities invalid size according to the formula:

when this part of the reliability associated with the destruction of the product and, therefore, potentially associated with health and/or life of the people and ecology of the product environment, defined as the safety characteristics of the product B (in accordance with the RF law "On technical regulation" dated, 15.12.2002), which is defined as the probability of the absence in the product discontinuities, in size equal to or what information is χ
_{kr}according to the formula:

Generally, as the characteristic dimension χ defect is selected linear dimension of the defect, or a combination of the linear dimensions of the defect, or the defect area, or volume of the defect.

In one embodiment, approximate the histogram (N_{OBN}that χ) by the equation

N_{OBN}(χ)=A_{1}χ^{-n1}{1-(1-η)exp[-α(χ-χ_{0})]-η} or

N_{OBN}(χ)=A_{2}exp(-n_{2}χ){1-(1-η)exp[-α(χ-χ_{0})]-η}

where A_{1}, A_{2}n_{1}n_{2}that α, η - constant, which is determined from the condition of the best approximation for N_{OBN}(χ) to the monitoring results, presented in the form of a histogram,

χ_{0}- minimum available for the detection of the defect size

the original defect N_{Ref}determined by the formula

N_{Ref}=Aχ^{-n}

and the probability of defect detection P_{water}according to the formula:

P_{water}=1-(1-η)exp[-α(χ-χ_{0})]-η

In the particular case as the characteristic dimension take minor axis and the ellipse, which schematize the defect, the ratio a/C take constant for all a, determined from the condition of maximum speed the development of the defect in service.

Minimal up is available for the detection of defect size χ
_{0}determine if the flaw detector setup used in the control of the product, or as the minimum size of defect that was detected during the inspection.

To simplify the calculations, constant η can be taken equal to 0.

In another embodiment, produce a test sample, designed to determine characteristics of non-destructive testing of discontinuities in the material, control of this test sample by the method of non-destructive testing and monitoring of the product, which is produced by the same method as the control test sample, the test sample is made in the form of a product or the most critical part of the same material and on the same technology as the product placed randomly defects with different characteristic sizes χdetermine the probability of detection of defects P_{water}(χ)

P_{water}(χ)=N_{OBN}(χ)/N_{hall then}(χ),

where N_{OBN}_{then}the number of detected during testing of the test specimen defects,

N_{hall}_{then}the number laid in the manufacture of sample defects

the original defect of the product is determined after NC products as

N_{Ref}=N_{OBN ed}/P_{water}(χ)

the histogram (N_{ex,}χ) approximated by the equation N_{Ref}=f(χ) or N_{Ref}=f(a,c), where a, C - line is by the size of defects,

and residual defects N_{OST}determined by the formula

N_{ocm}(χ)=N_{Ref}(χ)-N_{OBN ed}or

N_{ocm}(a,c)=N_{Ref}(a,c)-N_{OBN ed}(a,C)

When the test sample contains two groups of defects: defects, dimensions which lie in the area of defects, valid during operation, and the dimensions of which lie in the field of critical articles in the operation mode, and the defects simulate defects operational and technological nature.

The histogram (N_{ex,}χ) approximate equation of the type N_{Ref}=A_{χ}exp(-n_{χ}χ), or N_{Ref}=A_{and}exp(-n_{a}a), or N_{Ref}=A_{a,c}exp[-n_{a,c}(a^{2}/c)], or N_{Ref}=A_{F}exp(-nF), orororor

where a, is the linear size of the defect,

F - area defect

n, A - coefficients are chosen from the condition of maximum approach of the analytical curve to the experimental data.

Figure 1 shows a schematization of the defect in the pipe by an ellipse with semi-axes a and C, figure 2 - a collection of critical defects and sizes, figure 3 - histogram of the identified product defects, figure 4 curves of the original and residual defects, the probability of detecting the Def is tov.

The method can be used for a specific product or group of similar products, quality workmanship, reliability and security which you must provide with the application of the known method of non-destructive testing operator known qualification and subsequent repair of detected defects.

Methods of fracture mechanics to determine the critical defect size in the mode of operation for this product χ_{kr}and the maximum allowable operation defects [χ]_{de}(the norm of the defect), as defined by applicable regulations and/or specifications for the manufacture (for example, nuclear technology by regulatory methodology M-02-91, described in...), χ - the characteristic size of the defect, for example, is selected linear dimension of the defect, or a combination of the linear dimensions of the defect, or the defect area, or volume of the defect. It should be noted that the defects that determine the quality defects whose sizes are in the range from the minimum available for defect detection (search) to the size of defects that are valid in the manufacture and above; defects, determine reliability, is defects whose sizes are in the range from acceptance at the manufacturer to an acceptable during the operation above, the defects that determine the security is valid from when the operate is of critical dimensions and higher.

The set of defects of critical size (curve 3), valid in operation dimensions (curve 2), and the allowable size of the discontinuities in the manufacture of curve (1) shown in figure 2.

Conduct non-destructive testing products (NDT) method (ultrasonic, eddy current, radiography and other NDT methods and technical means of control operators specific skills and then eliminate it detected the defect (repair).

The testing results are in the form of a histogram in the coordinates of the characteristic defect size χ - the number of detected defects of a given size N_{OBN ed}".

Next, determine the probability of defect detection P_{water}the original defect N_{Ref}=f(χ) and residual defects N_{OST}=ϕ(χ) as the difference of N_{Ref}and N_{OBN}.

These dependencies can be determined by various methods.

According to one variant of the NDT results are in the form of analytical expressions.

The structure of the equation, which can describe the results of the TC represented by the histogram, figure 3, is as follows:

N_{OBN}(χ)=N_{Ref}(χ)P_{water}(χ)

where N_{OBN}- the number of detected during the inspection of defects per unit of characteristic size. If the characteristic time, the EPA selected the semiminor axis of the ellipse,
which schematize the defect, then the dimension of N_{OBN}mm^{-1};

N_{Ref}function source (up to NC and repair) defects with the same dimension, and N_{OBN},

P_{water}- the probability of detecting a defect of a given size χ.

The appearance of features N_{Ref}and R_{water}determined based on the condition of maximum simplicity of expression, the minimum number of constants and compliance physically due to dependency N_{Ref}and R_{water}from χ. In the first approximation can be used the following equations:

N_{Ref}=Aχ^{-n},

P_{water}=1-(1-η)exp[-α(χ-χ_{0})]-η

N_{OBN}(χ)=Aχ^{-n}{1-(1-η)exp[-α(χ-χ_{0})]-η}

where A, n, α, η, χ_{0}- constant.

Determine the numerical values of the constants A, n, α, η from the condition of maximum approximation equations N_{OBN}(χ) to the NDT results, presented in the form of a histogram.

When it χ_{0}- minimum available for the detection of defect size is determined when configuring the detector used in the control of the product, or as the minimum size of defect that was detected during the inspection; η in the first approximation can be taken equal to 0. The result is a three unknowns, which greatly facilitates the task of their definition.

To determine p is constant And, n α you can either solving the system of three equations for A, n and αreceive and that if we take three points on the histogram, or define them using the method of least squares.

Residual defects N_{OST}defined as the difference of N_{Ref}and N_{OBN}:

N_{OST}(χ)=N_{Ref}(χ)-N_{OBN}(χ).

The number remaining after NC and repair of defects in the product is determined in three ranges: residual defectsin the field of defects, important to safety, defined as the number of defects in the product, the dimensions of which are equal to or greater than the critical size χ_{kr}mode of operation:

whenwhenthe product has no stock of the security and may not be available for exploitation;

residual defectsin the area of defects is important for reliability, defined as the number of defects that are larger than the sizes of the defects [χ]_{de}maximum permissible product use:

whenwhen

the product has no safety margin;

where m is the number of the same products.

When building a GIS is Grammy horizontal axis χ must include a critical size defect, even if the control of all identified defects have not reached a critical size.

In the case of control a few of the same products all inspection results are summed and represented as a single histogram. The greater the number of products was controlled, the more we get the final result.

According to other variant to determine the dependencies of P_{water}(the probability of defect detection), N_{Ref}=f(χ) (original defect) and N_{OST}=ϕ(χ) (residual defects) make a test sample.

Taking into account the real operating loads and conditions determined for the product (e.g., pipeline, figure 1) methods of fracture mechanics (including safety factors) defects (discontinuities).

The set of defects of critical size (curve 3), valid in operation dimensions (curve 2), and the allowable size of the discontinuities in the manufacture of curve (1) shown in figure 2.

The test sample is made on the shape of the product and the scale of about 1:1 to the product or its most critical part. The most critical part of the product is that part of the product, in which the most likely defects (welds, designated maximum operational impacts and the like) or atrustee which is dangerous. A test specimen made of the same material and on the same technology as the product. In the test samples lay artificial defects of three types:

- defects whose sizes lie in the range from sizes of defects that are valid during operation, to the size of the critical items in the operation mode, defects,

- defects whose sizes lie in the range from sizes valid when manufacturing defects to the defect size, a valid operation.

While defects (discontinuities) should mimic the defects of an operational nature. Operational defects - defects that can arise from manufacturing defects or to germinate and grow under operating loads (fatigue cracks, cracked corrosion stress cracking and the like).

All inherent defects should be hidden from the operators NK, i.e. to be internal (subsurface) or, if the defect surface, located in a place inaccessible to visual detection (or a size that it is impossible to capture visually).

It should also be noted that the defects include in the sample randomly, for example, using tables of random numbers.

The minimum allowable distance between the defects is determined proceeding from the conditions of existence of solitary Def is tov (if laid a single defects) or less for group cracks (conditions of mutual influence is known, for example, guidelines Mr 108.7-86, M, TSNIITMASH, 1986).

The number of defects of each type should be sufficient for statistical analysis of the results, for example, not less than 9 pieces (fewer results less reliable.)

Any defect can be modeled conservatively crack, and any crack can be described by an ellipse with semi-axes: short and long S.

There are various options bookmark defects in the test sample.

In the test sample lay defects in the form of ellipses, and the ratio of the axes of the ellipse accept on the basis of the maximum velocity defect growth in operational stress field.

In the test sample lay defects in the form of ellipses, the ratio of the axes of the ellipse accept arbitrary, and as characterizes the size of the defect size take the square planar defect or the projected area of the voluminous defect on the plane of the probable development of the defect.

In the test sample lay defects in the form of ellipses, with the number of defects and the ratio of the axes of the ellipse is chosen using the mathematical methods of experiment planning on the basis of minimizing the number of laying defects (Kdaniel. Application of statistics in industrial experiment, in Mir, M. 1979.

If put to the test sample defects not have the shape of an ellipse, they schematize ellipses.

After fabrication of the test sample to produce a control using the same tools and methods for monitoring and operators of the same qualification, which will then be used to control the product, the inspection results are compared with real defects inherent in the test sample.

For each characteristic dimension of the defect is determined reliability as a function of defect detection probability P_{water}(χ)

P_{water}(χ)=N_{OBN}(χ)/N_{hall then}(χ),

where N_{OBN}_{then}the number of detected during testing of the test specimen defects,

N_{hall then}the number laid in the manufacture of sample defects.

Control build a curve of the probability of detection of defects in the part of this NDT method depending on the characteristic size of the defect. The curve of the probability of detection of defects from the defect dimensions "a" and "C" (any defect in the material of the conservative can be described by an ellipse with semi-axes a and C) can be approximated most closely describes the experimental results of the control equation, for example

P_{water}=1-(1-η)exp[-α_{HK}(a-a_{0})(c-c_{0})]-ηor

and the

P_{water}=1-(1-η)exp[-α_{HK}(χ-χ_{0})]-η

Where α_{HK}the confidence factor NC, characterizes the increase in the detection of defects depending on its size;

η - constant characterizing the limit of detectability of control by this method with arbitrarily large size of the defect; if the detail sizes small, then this value can be neglected by typing the corresponding adjustment values α_{HK};

χ - the characteristic size of the defect, for example, its area;

χ_{0}- the minimum characteristic dimension of the defect;

and_{0}with_{0}- the minimum size of defects that are available for the detection of NK.

Then hold control of the product and the testing results are in the form of a histogram in the coordinates of the characteristic defect size χ - the number of detected defects of a given size N_{OBN ed}".

The original defect N_{Ref}determine the ratio of N_{OBN}_{ed}/P_{water}(χ); the resulting histogram is approximated by the equation N-type_{Ref}=A_{χ}exp(-n_{χ}χ)ororororor

where a, is the linear size of the defect,

ρ_{with}the distribution function of magnitude, for example the normal distribution law,

F - area defect

n, A, D,the coefficients are chosen from the condition of maximum approach of the analytical curve to the experimental data, while- the average value, D is the dispersion.

As the characteristic dimension, you can take a small semi-axis a of the ellipse, which schematize the defect, the ratio a/C take constant for all and on the basis of the maximum velocity defect growth in operating conditions;

for example, in the case of a uniform stress field and/s=2 and the normal law distribution with an average value of C=2A and dispersion D=a/2 received

Residual defects get as the difference between the N_{Ref}and N_{OBN}_{ed}. In this case N_{OBN ed}determine from the analytical expressions of N_{Ref}·P_{water}(χ), i.e. the residual defect N_{OST}can be represented in the form of the equation

N_{OST}=N_{Ref}(1-P_{water}).

The safety of the product B is defined as the probability of the absence of product defects, greater than or equal to χ_{kr}where residual defectsin the region of the STI defects,
important to safety, defined as the number of defects in the product, the dimensions of which are equal to or greater than the critical size χ_{kr}mode of operation:

residual defectsin the area of defects is important for reliability (reliability N), defined as the probability of zero defects larger than the defect size χ_{d,e}limit of use of the product:

Next, the residual defects are divided into significant part χ≤χ_{d},_{}in which defects with sizes χ≤χ_{d}there are authentic, and a probabilistic part χ>χ_{d}in which defects with sizes χ>χ_{d}may or may not be.

The boundary between true and probabilistic parts of residual defects is determined from the conditions:

where χ_{max}- maximum size of defects in this product.

For the probabilistic part of the residual defects determine the probability of existence of defects larger than χ_{kr}and defects larger than [χ]_{de}

Product safety is defined as the probability of the existence of defects, once the minimum level which exceeds χ
_{kr}and reliability of the product is defined as the probability of defects larger than [χ]_{de}

The invention is illustrated by the following example.

It is necessary to ensure the quality of the two pipes of internal diameter D=800 mm, wall thickness S=34 mm from pearlitic steel. Critical size defects in girth welds are presented in figure 2 (curve 1). Valid in operation defects determined using the equations of fracture mechanics and factors of safety (curve 2 in figure 2). Norms of defects in the operation are presented in figure 2 curve 3.

In the NC standard method and means prior to the operation (after installation) was discovered 60 discontinuities.

All identified discontinuities (defects) are presented as histograms in figure 3.

At the same time as the characteristic dimension of the defect selected width of the defect in the direction of the thickness of the wall - or rather, the semiminor axis of the ellipse, which was shemaleshemale all identified defects.

When the ratio a/c≈0,5 critical size defect corresponds to a=15 mm, [and]_{de}=6 mm, [and]_{technology.}=1.15 mm (figure 2).

Despite the fact that the maximum size of the defect detected was_{max}=13 mm, the x-axis contains the critical size a=15 mm

The equation describing the number of detected defects N

N_{OBN}=AA^{-n}[1-exp[-α(a-a_{0})].

Control minimum detected defect had a=0.6 mm

To determine the constant A, n, α solve the system of three equations with respect to these constant:

The 1st equation to get the point with coordinates (a=1 mm, N_{OBN}=20) figure 3:

20=A·1^{-n}[1-exp[-α(1-0,6)]];

2nd equation to get the point with coordinates (a=5 mm, N_{OBN}=4) figure 3:

4=A·5^{-n}[1-exp[-α(5-0,6)]];

The 3rd equation to get the point with coordinates (a=13 mm, N_{OBN}=0,66) figure 3:

0,66=A·13^{-n}[1-exp[-α(13-0,6)]].

For the 3rd equation of N_{OBN}=0,66 obtained as the averaged number of detected defects in the interval from 11 to 13 mm, which accounted for 2/3, where 2 is the number of detected defects, 3 - the number of intervals.

Finally, the system of equations has the form:

20=A·[1-exp(-0,4α)]

4=A·5^{-n}[1-exp[(-4,4α)]];

0,66=A·13^{-n}[1-exp(by 12,4α)]].

Solving the system of equations for A, n, α gave the following results:

A=1000 mm, n=2,56, α=0.05 mm^{-1}.

Substituting the constants a, n, α in the corresponding equations, get:

the equation of the original defects:

N_{Ref}=1000A^{-2,56};

the equation of the probability of defect detection:

P_{water}=1-exp[-0,05(0,6)];

equation residual defectness the

N_{OST}(χ)=N_{Ref}(χ)-N_{OBN}(χ).

The equations presented in figure 4.

Solve the equation

and

At the same time_{max}=S, where S is the thickness of the pipe wall. The results of the solutions are presented in figure 5 as curve 1. Valid in operation and critical defects are marked [a] and a_{kr}

Finally got

and_{d}=14 mm; H=1-1=0; B=1-0,55=0,45.

Since the values of reliability and security characteristics of residual defects in accordance with curve 1 unacceptably low, the product was rejected and sent back for revision. After completion of the product re-inspection and repair of the product, which was obtained curve 2. In this case, the reliability was

and security was

According to the obtained results the product was made in the operation.

1. The method of determining the reliability and security products, including the identification of defects in products NDT method, characterized in that determines for a particular product or group m the same products critical dimensions χ_{kr}defects in the operate mode valid in operation dimensions [χ
]_{de}defects, the inspection results are in the form of a histogram in the coordinates (N_{OBN,}χ), where N_{OBN}- the number of detected during the inspection of defects, χ - the characteristic size of the defect, and when the control m the same products inspection results summarize and present in a single histogram, determine the probability of defect detection P_{water}determine the original defect N_{Ref}=f(χ), determine the residual defect N_{OST}ϕ(χ) as the difference of N_{Ref}and N_{OBN}residual defects are divided into significant part χ≤χ_{d}and probabilistic part χ>χ_{d}where χ - the characteristic defect size χ_{d}- the size of the defects at the boundary between true and probabilistic parts defined from

where χ_{max}- maximum size of defects in this product;

for the probabilistic part of the residual defects determine the reliability of the product N as the probability of the absence in the product discontinuities invalid size according to the formula

when this part of the reliability associated with the destruction of the product, defined as the safety characteristics of the product B, which is defined as the probability of Ustia product discontinuities,
size equal to or greater χ_{kr}according to the formula

2. The method according to claim 1, characterized in that as the characteristic dimension χ defect is selected linear dimension of the defect, or a combination of the linear dimensions of the defect, or the defect area, or volume of the defect.

3. The method according to claim 1, characterized in that approximate the histogram (N_{OBN}that χ) by the equation:

N_{OBN}(χ)=A_{1}χ^{-n1}{1-(1-η)exp[-α(χ-χ_{0})]-η} or

N_{OBN}(χ)=A_{2}exp(-n_{2}χ){1-(1-η)exp[-α(χ-χ_{0})]-η},

where a_{1}And_{2}n_{1}n_{2}that α, η - constant, which is determined from the condition of the best approximation for N_{OBN}(χ) to the monitoring results, presented in the form of a histogram;

χ_{0}- minimum available to identify the size of the defect, the original defect N_{Ref}determined by the formula

N_{Ref}=Andχ^{-n},

and the probability of defect detection P_{water}the formula

P_{water}=1-(1-η)exp[-α(χ-χ_{0})]-η.

4. The method according to claim 3, characterized in that as the characteristic dimension adopt small semi-axis a of the ellipse, which schematize the defect, the ratio a/C, where C is balsamroot ellipse, take a constant for all a, determined from the condition of maximum speed the development of the defect in service.

5. The method according to claim 3 or 4, characterized in that the minimum available for the detection of defect size χ_{0}determine if the flaw detector setup used in the control of the product, or as the minimum size of defect that was detected during the inspection.

6. The method according to claim 3 or 4, characterized in that the constant η take 0.

7. The method according to claim 1 or 2, characterized in that the manufactured test pattern designed to determine characteristics of non-destructive testing of discontinuities in the material, control of this test sample by the method of non-destructive testing and monitoring of the product, which is produced by the same method as the control test sample, the test sample is made in the form of a product or the most critical part of the same material and on the same technology as the product placed randomly defects with different characteristic sizes χdetermine the probability of detection of defects P_{water}(χ):

P_{water}(χ)=N_{OBN.}_{then}(χ)/N_{hall.}_{then}(χ),

where N_{OBN.}_{then}the number of detected during testing of the test sample defects;

N_{hall.
thenthe number laid in the manufacture of sample defects, the original defect is defined as}

N_{Ref}=N_{OBN.}_{ed}/P_{water}(χ),

the histogram (N_{ex,}χ) approximated by the equation N_{Ref}=f(χ) or N_{Ref}=f(a,C), where a, is the linear size of defects,

and residual defects N_{OST}determined by the formula

N_{OST}(χ)=N_{Ref}(χ)-N_{OBN.}_{ed}or

N_{OST}(a,c)=N_{Ref}(a,c)-N_{OBN.}_{ed}(a,c).

8. The method according to claim 7, characterized in that the test sample contains clusters of defects: defects, dimensions which lie in the area of defects, valid during operation, and the dimensions of which lie in the field of critical articles in the operation mode, and the defects simulate defects operational and technological nature.

9. The method according to claim 7, characterized in that the histogram (N_{Ref}thatχ) approximate equation of the type N_{Ref}=And_{χ}exp(-n_{χ}χ), or N_{Ref}=And_{a}exp(-n_{a}a), or N_{Ref}=A_{a,c}exp[-n_{a,c}(a^{2}/(C)], or N_{Ref}=And_{F}exp(-nF), oror

where a, is the linear size of the defect;

F - defect area;

n, A - coefficients, select the e from the condition of maximum approach of the analytical curve to the experimental data.

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1 dwg

**FIELD: instrumentation engineering; serviceability check of multichannel communication systems.**

**SUBSTANCE: proposed equipment includes personal computer, multiplexing switch, circuit checkup unit, control unit, multichannel comparison unit, virtual standard, switching unit, output signal shaper, multiplexer, and normalizing unit that has voltage meter and circuit meter.**

**EFFECT: enlarged functional capabilities of device.**

**3 cl, 1 dwg**

FIELD: mechanical engineering.

SUBSTANCE: method comprises determining variations of the parameter during acceleration and deceleration of the actuator. The device comprises generator and OR-NOT unit, the inputs of which are connected with the outputs of the relay. The output of the relay is connected with the input of the generator.

EFFECT: enhanced accuracy of the method and simplified device.

3 dwg

FIELD: electric measurements, applicable in check-up of tram and trolleybus electric apparatuses in the process of manufacture and in service.

SUBSTANCE: current in the current source is fed to the current winding of the current relay from the rectifier via a key, choke, shunt. The device uses a pulse-width modulator that controls the keys, slowly varying voltage is applied to the modulating input of the pulse-width modulator that is preliminarily modulated by the rectifier ripple voltage. Besides, use is made of a sample-release circuit of operate (release) currents and voltages. The signals from these circuits are fed to indicators via analog-to-digital converters.

EFFECT: reduced error of determination of operate and release current and voltage relays, enhanced capacity of check-up in the device due to reduced ripples of the source of smoothly varying current.

2 cl, 4 dwg

FIELD: measuring and monitoring technique, possibly monitoring of different objects.

SUBSTANCE: system includes control unit, unit for calling testing programs, coupling unit, measuring unit, test stimulation unit, power sources, unit for distributing signals, memory unit, N matching units, N testing program units. Each testing-program unit has evaluation circuit and two memory devices.

EFFECT: lowered volume of equipment, simplified organization of monitoring process and development of software.

1 dwg

FIELD: automatic control, applicable in systems with excessive quality of transducers, for example, accelerometers, a failure of one of which should not result in a failure of the control system.

SUBSTANCE: the method is based on a periodic check-up of relation between the measured parameters of motion characterizing the correct operation of the transducers, fixation of the moment of failure of the relation, comparison of the readings of the transducers at this moment and at the moment preceding the moment of disturbance of the relation, and determination of the failed transducer by the results of the comparison.

EFFECT: expanded functional potentialities due to possibility of determination of the failed transducer in any excess system.

1 dwg

FIELD: automatic control, applicable in systems with excessive quality of transducers, for example, accelerometers, a failure of one of which should not result in a failure of the control system.

SUBSTANCE: the method is based on a periodic check-up of relation between the measured parameters of motion characterizing the correct operation of the transducers, fixation of the moment of failure of the relation, comparison of the readings of the transducers at this moment and at the moment preceding the moment of disturbance of the relation, and determination of the failed transducer by the results of the comparison.

EFFECT: expanded functional potentialities due to possibility of determination of the failed transducer in any excess system.

1 dwg

FIELD: measuring and monitoring technique, possibly monitoring of different objects.

SUBSTANCE: system includes control unit, unit for calling testing programs, coupling unit, measuring unit, test stimulation unit, power sources, unit for distributing signals, memory unit, N matching units, N testing program units. Each testing-program unit has evaluation circuit and two memory devices.

EFFECT: lowered volume of equipment, simplified organization of monitoring process and development of software.

1 dwg

FIELD: electric measurements, applicable in check-up of tram and trolleybus electric apparatuses in the process of manufacture and in service.

SUBSTANCE: current in the current source is fed to the current winding of the current relay from the rectifier via a key, choke, shunt. The device uses a pulse-width modulator that controls the keys, slowly varying voltage is applied to the modulating input of the pulse-width modulator that is preliminarily modulated by the rectifier ripple voltage. Besides, use is made of a sample-release circuit of operate (release) currents and voltages. The signals from these circuits are fed to indicators via analog-to-digital converters.

EFFECT: reduced error of determination of operate and release current and voltage relays, enhanced capacity of check-up in the device due to reduced ripples of the source of smoothly varying current.

2 cl, 4 dwg

FIELD: mechanical engineering.

SUBSTANCE: method comprises determining variations of the parameter during acceleration and deceleration of the actuator. The device comprises generator and OR-NOT unit, the inputs of which are connected with the outputs of the relay. The output of the relay is connected with the input of the generator.

EFFECT: enhanced accuracy of the method and simplified device.

3 dwg

**FIELD: instrumentation engineering; serviceability check of multichannel communication systems.**

**SUBSTANCE: proposed equipment includes personal computer, multiplexing switch, circuit checkup unit, control unit, multichannel comparison unit, virtual standard, switching unit, output signal shaper, multiplexer, and normalizing unit that has voltage meter and circuit meter.**

**EFFECT: enlarged functional capabilities of device.**

**3 cl, 1 dwg**

FIELD: measuring equipment.

SUBSTANCE: as a source of standard signal not separate generator of test signal according to known code structure is used, but a component of modem, to provide for substantial simplification of process under unfavorable conditions.

EFFECT: higher efficiency.

1 dwg

FIELD: automated control and diagnostics systems.

SUBSTANCE: first variant of complex includes control computer, mating block, commutator, local data exchange main, tests forming block, logical analyzer, signature analyzer, synchronization block, digital oscillographs block, special form signals programmed generators block, programmed power-sources block. Second variant of complex additionally includes block for forming high-frequency test signals and block for measuring high-frequency signals.

EFFECT: broader functional capabilities, higher efficiency, higher reliability.

2 cl, 2 dwg

FIELD: automatic control.

SUBSTANCE: device has first and second analog-digital converters, first and second coefficients forming blocks, first and second multiplication blocks, counter, first and second integrator, control effect forming device, division block, buffer and registering block, while coefficients forming blocks are made in form of digital filters and all remaining blocks of device are made digital.

EFFECT: higher precision, higher resistance to interference.

1 dwg

FIELD: measuring equipment.

SUBSTANCE: device has block for forming control and stimulation signals, block for forming standard signals, multiplication blocks, frequency transformer, phase rotator, commutator, frequencies grid generator, integrators, blocks for square involution, adder, normalization block, key, analog-digital converter, comparison circuits, memory blocks, registers, information output block, interval estimation block (for setting lower and upper limits of trust range for each measured value of mutual difference coefficient of distorted and standard signals) and block for analysis of number of support values of mutual difference coefficient (to exclude from further processing results of measurements, for which within limits of trust interval number of support values of coefficient exceeds allowed limit).

EFFECT: higher precision.

2 cl, 2 dwg

FIELD: technical diagnostics.

SUBSTANCE: method includes, for each set of input test signals, forming of prior matching response signals for intermediate points of controlled device. Received response signals at outputs of product are compared to parameters of standard response signals and level of their match is determined, in case of mismatches broken branch of functional circuit is determined and diagnostics is repeated by substituting all formed combinations of input signals, after that diagnostics of erratic portions is started.

EFFECT: simplified method.

3 dwg