METHOD OF EXAMINING A COMPONENT

Abstract

A method for examining a component with the steps: Determining an actual value of a first parameter of a first characteristic of the component; Determining an actual value of the first parameter of at least one further characteristic of the component; Determining a first statistical characteristic variable of these actual values of the first parameter; and Classifying the component on the basis of the first statistical characteristic variable and the actual values of the first parameter,
wherein the component is classified in a predetermined quality class if the first statistical characteristic variable is outside a predetermined first characteristic variable range or at least one of these actual values of the first parameter is outside a predetermined first range of values.

Claims

1.-9. (canceled)

10. A method for examining a component, wherein the method comprises: determining an actual value of a first parameter of a first characteristic of the component; determining an actual value of the first parameter of at least one further characteristic of the component; determining a first statistical characteristic variable of the actual values of the first parameter; and classifying the component on the basis of the first statistical characteristic variable and the actual values of the first parameter, the component being classified in a predetermined quality class if the first statistical characteristic variable is outside a predetermined first characteristic variable range or at least one of the actual values of the first parameter is outside a predetermined first range of values.

11. The method of claim 1, wherein the method further comprises: determining an actual value of a second parameter of the first characteristic of the component; determining an actual value of the second parameter of the at least one further characteristic of the component; and determining a second statistical characteristic variable of the actual values of the second parameter; the component being classified on the basis of the second statistical characteristic variable and the actual values of the second parameter and being classified in the predetermined quality class if the second statistical characteristic variable is outside a predetermined second characteristic variable range or at least one of the actual values of the second parameter is outside a predetermined second range of values.

12. The method of claim 11, wherein the method further comprises: determining at least a third statistical characteristic variable of the actual values of the first-parameter; and/or determining at least a fourth statistical characteristic variable of the actual values of the second parameter; the component being classified on the basis of the third statistical characteristic variable and/or the fourth statistical characteristic variable and being classified in the predetermined quality class if the third statistical characteristic variable is outside a predetermined third characteristic variable range or if the fourth statistical characteristic variable is outside a predetermined fourth characteristic variable range.

13. The method of claim 12, wherein the first statistical characteristic variable and/or the second statistical characteristic variable and/or the third statistical characteristic variable and/or the fourth statistical characteristic variable has at least a statistical situational measure, at least a statistical measure of dispersion and/or at least a predetermined tolerance value of the first and/or second range of values, and/or the first characteristic variable range and/or the second characteristic variable range and/or the third characteristic variable range and/or the fourth characteristic variable range depends on at least one predetermined tolerance value of the first and/or second range of values.

14. The method of claim 13, wherein the statistical situational measure is an average and/or a quantile.

15. The method of claim 13, wherein the statistical measure of dispersion is a variance or a standard deviation.

16. The method of claim 13, wherein the predetermined tolerance value is an upper tolerance value and/or a lower tolerance value.

17. The method of claim 10, wherein the component is discarded or reworked if it has been classified in the predetermined quality class.

18. The method of claim 10, wherein the first and/or second range of values is predetermined according to a method in which the first range of values is predetermined on the basis of an assumed statistical frequency distribution of the actual values of the first parameter within the characteristics of the component and/or the second range of values is predetermined on the basis of an assumed statistical frequency distribution of the actual values of the second parameter within the characteristics of the component.

19. The method of claim 10, wherein the component is an aircraft engine.

20. A system for examining a component, wherein the component is set up for carrying out the method of claim 10 and/or comprises: elements for determining a first statistical characteristic variable of determined actual values of a first parameter of a first characteristic of the component and at least one further characteristic of the component; and/or elements for classifying the component on the basis of the first statistical characteristic variable and the actual values of the first parameter, the component being classified in a predetermined quality class if the first statistical characteristic variable is outside a predetermined first characteristic variable range or at least one of the actual values of the first parameter is outside a predetermined first range of values.

21. A computer program product, wherein the product comprises a program code which is stored on a medium readable by a computer, for carrying out the method of claim 10.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0096] Further advantageous developments of the present invention result from the subordinate claims and the following description of preferred embodiments. For this purpose the figures show partially schematized representations as follows:

[0097] FIG. 1 shows a component examined by a method according to an embodi ment of the present invention;

[0098] FIG. 2: shows a detail of the component of FIG. 1;

[0099] FIG. 3 shows the method for examining the component; and

[0100] FIG. 4 shows a system for carrying out the method.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0101] The particulars shown herein are by way of example and for purposes of illustrative discussion of the embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the present invention. In this regard, no attempt is made to show details of the present invention in more detail than is necessary for the fundamental understanding of the present invention, the description in combination with the drawings making apparent to those of skill in the art how the several forms of the present invention may be embodied in practice.

[0102] FIG. 1 shows a rotor 10 of a gas turbine with 12 similar holes 11.1, 11.2, . . . , 11.12 in an axial top view, FIG. 2 shows the hole 11.1 by way of example.

[0103] The hole 11.1 represents a first characteristic of the rotor 10, the holes 11.2, . . . , 11. 12 each represent another characteristic of the rotor.

[0104] For parameters of these characteristics 11.1, 11.2, . . . ,11.12, S10 (cf. FIG. 3) target values as well as upper and/or lower tolerance values are predetermined, which define corresponding ranges of values or tolerance ranges.

[0105] For example, for a first parameter DM in the form of a diameter of the holes, a target value of 5 mm, a maximum permissible upwards deviation of 0.1 mm or an upper tolerance value OT.sub.DM of 5.1 mm and a maximum permissible deviation downwards of 0.1 mm or a lower tolerance value UT.sub.DM of 4.9 mm is predetermined, which defines a first range of values or of tolerance range [4.9 mm; 5.1 mm]. Alternatively, for example, the flatness of functional surfaces of grooves or the like could be predetermined, wherein the value of the corresponding flatness indicates in a customary manner the permissible plane spacing between two parallel surfaces, which define between themselves a gap-shaped tolerance zone in which the functional surface is to lie.

[0106] Also by way of example, for a second parameter POS in the form of a hole circle diameter or a radial distance from the respective hole to the rotor center, a target value of 200 mm, a maximum permissible upwards deviation of 0.2 mm or an upper tolerance value OT.sub.POS of 200.2 mm is predetermined and a maximum permissible downwards deviation of 0.2 mm or a lower tolerance value UT.sub.POS of 199.8 mm is predetermined, which defines a second range of values or tolerance range [199.8 mm; 200.2 mm].

[0107] Initially, without taking into account statistical frequency distributions of the parameter values in a known manner, for example on the basis of corresponding strength calculations, safety parameters and the like, respective tolerance fields are predetermined for the parameters DM, POS. This is familiar to the person skilled in the art and therefore does not need to be described further here.

[0108] Then, in step S10, a normal distribution with an average value and a standard deviation is used as the basis for each of the parameters and the corresponding tolerance field mentioned above is increased in proportion to the standard deviation, which provides the aforementioned range of values or tolerance range [4.9 mm; 5.1 mm] for the parameter DM and [199.8 mm; 200.2 mm] for the parameter POS.

[0109] Step S10 thus provides a method for predetermining the first range of values [4.9 mm; 5.1 mm] for the first parameter DM and the second range of values [199.8 mm; 200.2 mm] for the second parameter POS.

[0110] In a step S20, the actual values of the parameters DM, POS are determined.

[0111] In a step S30, a first statistical characteristic variable for the first parameter DM is determined in the form of the customarily defined arithmetic mean M.sub.DM over all 12 holes, i.e. the actual-values DM.sub.i, i=11.1, . . . , 11.12:

M.sub.DM=(Σ.sub.i=11.1.sup.11.12DM.sub.i)/12

and a third statistical characteristic variable is determined in the form of a statistical index IO.sub.DM over all holes i=11.1, . . . , 11.12:

IO.sub.DM=(OT.sub.DM−M.sub.DM)/(3s.Math..sub.DM)

with the customarily defined (empirical) standard deviation

s.sub.DM=[Σ.sub.i=11.1.sup.11.12(DM.sub.i−M.sub.DM).sup.2/12].sup.0.5

and another third statistical characteristic variable is determined in the form of another statistical index IU.sub.DM over all holes i=11.1, . . . ,11.12:

IU.sub.DM=(M.sub.DM−UT.sub.DM)/(3s.Math..sub.DM).

[0112] It can be seen that the first statistical characteristic variable is the statistical mean value M.sub.DM , the one third statistical characteristic variable IO.sub.DM is a statistical situational measure in the form of this mean value, a statistical measure of dispersion in the form of the standard deviation DM and the upper tolerance value OT.sub.DM of the first parameter DM or the first range of values and the other third statistical characteristic variable has the lower tolerance value UT.sub.DM of the first parameter DM or the first range of values instead of the upper tolerance value.

[0113] In addition, in step S30 a second statistical characteristic variable is determined for the second parameter POS in the form of the arithmetic mean M.sub.POS over all 12 holes, i.e. the actual-values POS.sub.i,i=11.1, . . . , 11.12:

M.sub.POS=(Σ.sub.i=11.1.sup.11.12POS.sub.i)/12

a fourth statistical characteristic variable is determined in the form of a statistical index IO.sub.POS over all holes i=11.1, . . . ,11.12:

IO.sub.POS=(OT.sub.POS−M.sub.POS)/(3s.Math..sub.POS)

with the (empirical) standard deviation

s.sub.POS=[Σ.sub.i=11.1.sup.11.12(POS.sub.i−M.sub.POS).sup.2/12].sup.0.5

and another fourth statistical characteristic variable is determined in the form of another statistical index IU.sub.POS over all holes i=11.1, . . . ,11.12:

IU.sub.POS=(M.sub.POS−UT.sub.POS)/(3s.Math..sub.POS).

[0114] Then, in a step S40, it is checked whether at least one of the actual values of the parameters DM, POS is outside the corresponding range of values, i.e. in particular one of the actual values DM.sub.i, i=11.1, . . . , 11.12 outside the first range of values [4.9 mm; 5.1 mm] or one of the actual values POS.sub.i, i=11.1, . . . ,11.12 outside the second range of values [199.8 mm; 200.2 mm].

[0115] If this is the case (S40: “Y”), the rotor is classified as defective (S45) and, if appropriate, is separated out or reworked (S48).

[0116] Otherwise (S40: “N”) it is checked in a step S50 whether the first statistical characteristic variable M.sub.DM is outside a predetermined first characteristic variable range, which depends on the upper tolerance value OT.sub.DM and the lower tolerance value UT.sub.DM of the first range of values, in the exemplary embodiment whether the following applies:

M.sub.DM>OT.sub.DM+0.05 mm or M.sub.DM<UT.sub.DM−0.05 mm,

whether the second statistical characteristic variable M.sub.POS is outside a predetermined second characteristic variable range, which depends on the upper tolerance value OT.sub.POS and the lower tolerance value UT.sub.POS of the second range of values, in the exemplary embodiment whether:

M.sub.POS>OT.sub.POS+0.1 mm or M.sub.POS<UT.sub.POS−0.1 mm,

whether one of the third statistical characteristic variables IO.sub.DM, IU.sub.DM is outside a predetermined corresponding third characteristic variable range, in the exemplary embodiment whether:

IO.sub.DM<1.5 or IU.sub.DM>1.5

or one of the fourth statistical characteristic variables IO.sub.POS, IU.sub.POS is outside the corresponding fourth characteristic variable range, in the exemplary embodiment, whether the following applies:

IO.sub.POS<1 or IU.sub.POS>1

[0117] If at least one of these conditions is met (S50: “Y”), the rotor is also classified as defective (S45) and, if appropriate, is separated out or reworked (S48).

[0118] If all actual values are within the predetermined range of values or tolerance range (S40: “N”) and all statistical characteristic variables are within the predetermined characteristic variable ranges (S50: “N”), the rotor has passed this component examination (S60).

[0119] FIG. 4 shows a system for at least partially automated embodiment of the method described above in the form of a computer 100, which is set up to classify the rotor as a reject or good on the basis of entered actual values.

[0120] Although exemplary implementations have been explained in the preceding description, it should be noted that a variety of variations are possible. In addition, it should be noted that the exemplary embodiments are only examples that are not intended to restrict the scope of protection, the applications and the design in any way. Rather, the preceding description gives the person skilled in the art a guide for the implementation of at least one exemplary embodiment, wherein various changes, in particular with regard to the function and arrangement of the described components, can be made without departing from the scope of protection as it results from the claims and equivalent combinations of features.

REFERENCE CHARACTER LIST

[0121] 10 rotor (component)

[0122] 11.1,

[0123] 11.2,

[0124] 11.12 hole (characteristic)

[0125] 100 computer (system)