DE102019205584A1 - Method and device for adjusting and / or calibrating an ultrasonic test - Google Patents

Abstract

A method for adjusting and / or calibrating an ultrasonic test of an object is proposed in which ultrasound is insonified into the object by means of N ≥ 2 ultrasonic transmitters and / or in which at least part of the insonified ultrasound is detected by means of N ≥ 2 ultrasonic receivers. The method is characterized in that a time signal of the sonicated ultrasound is recorded for several paired combinations of the ultrasonic transmitters and ultrasonic receivers, and a speed of sound of at least one wave mode of the sonicated ultrasound is determined without form echo based on the plurality of recorded time signals. The invention also relates to a device for adjusting and / or calibrating an ultrasonic test of an object.

Description

The invention relates to a method according to the preamble of patent claim 1. Furthermore, the invention relates to a device according to the preamble of patent claim 12.

To carry out an ultrasonic test of an object, an adjustment and / or calibration of distances is typically necessary (distance adjustment and / or distance calibration), for example to localize defects in the object and to decide whether these are located in critical areas of the object. Adjustment and / or calibration is also important for the interpretation of the ultrasonic test.

A suitable ultrasonic echo (shape echo), for example a back wall echo, an associated sound path and, if necessary, an adjustment body is required for the distance adjustment. A pulse echo measurement is used to determine the transit time of the ultrasound for the shape echo, thereby calculating the speed of sound.

For probes that have a significant lead time, a two-point adjustment is carried out and / or the lead time is determined by means of an adjustment body.

The speed of sound must be known precisely for the adjustments mentioned. Furthermore, the object itself must enable a shape echo, for example through a suitable rear wall. Furthermore, the area of the object and / or the object itself provided for the shape echo must be accessible. In summary, the adjustments mentioned are not suitable for all objects.

The disadvantage of the known methods for adjustment and / or calibration is that they are associated with a high expenditure of time. In particular, the determination of the speed of sound of shear waves is very time-consuming.

The present invention is based on the object of improving an adjustment and / or calibration of an ultrasonic test.

The object is achieved by a method with the features of independent patent claim 1 and by a device with the features of independent patent claim 12. Advantageous configurations and developments of the invention are specified in the dependent claims.

In the method according to the invention for adjusting and / or calibrating an ultrasonic test of an object, ultrasound is insonified into the object by means of N ≥ 2 ultrasonic transmitters and / or at least part of the insonified ultrasound is detected by means of N ≥ 2 ultrasonic receivers. The method according to the invention is characterized in that a time signal of the sonicated ultrasound is recorded for several paired combinations of the ultrasonic transmitters and ultrasonic receivers, and a speed of sound of at least one wave mode of the sonicated ultrasound is determined without form echo based on the several recorded time signals.

An object can be any spatial object, movable or immobile, in particular a workpiece, a semi-finished product, a component, a turbine, part of a building, part of a bridge and / or another tangible object.

A time signal typically corresponds to an A-scan or can be taken from an A-scan, which was determined based on the insonified and recorded ultrasound. A time signal (A-scan) is recorded for every possible transmitter-receiver combination (up to N ² ). The time signals can be determined or recorded by means of various methods, for example by means of a zero crossing of the ultrasound amplitude, by means of determining the time of first use and / or by means of phase spectroscopy. To improve the signal-to-noise ratio, selected time signals can also be omitted or weighted in a specific manner, for example time signals that have a negative influence on the adjustment and / or calibration or that correspond to a specific shape echo.

If, in addition to the time signal, an associated ultrasound amplitude is recorded and evaluated, a sound attenuation of the wave mode, in particular a Rayleigh wave and / or creeping wave, can also be determined.

According to the present invention, at least two ultrasonic transmitters and / or at least two ultrasonic receivers are used. If two ultrasonic transmitters are used, at least one ultrasonic receiver is required. If two ultrasonic receivers are used, at least one ultrasonic transmitter is required. The same number and more than two ultrasonic transmitters and ultrasonic receivers are preferably used. In other words, N 2 ultrasonic transmitters and N 2 ultrasonic receivers are preferably used and a time signal is determined for each of the N ² paired combinations. In other words, N ultrasound apertures, which are designed as transmission and / or reception apertures, are preferably used.

The inventive use of a plurality of transmitter-receiver pairs (and their permutations) enables improved adjustment and / or calibration.

An advantage of the present invention is that no shape echo and / or adjustment body is required for the adjustment and / or calibration of the ultrasonic test. In other words, the speed of sound is determined without a form echo, that is to say without the use of a form echo. As a result, the method according to the invention can be integrated directly into the ultrasonic test. In other words, the adjustment and / or calibration according to the invention is an integral part of the ultrasonic test. Furthermore, the adjustment and / or calibration takes place automatically so that intervention by the tester is no longer necessary. At best, the tester of the ultrasonic test does not notice the adjustment and / or calibration according to the invention, which typically takes place before the actual ultrasonic test. In other words, an ultrasonic test according to the invention comprises the method according to the invention for adjustment and / or calibration as a method step.

Another advantage of the present invention is that the adjustment and / or calibration is carried out directly on the object, as a result of which possible deviations from a reference body can be avoided. Errors can thereby be reduced, as a result of which the accuracy of the ultrasonic test, which is based on the adjustment and / or calibration according to the invention, is improved.

The device according to the invention for adjusting and / or calibrating an ultrasonic test of an object comprises at least N ≥ 2 ultrasound transmitters for irradiating ultrasound into the object, and / or at least N ≥ 2 ultrasonic receivers for detecting at least part of the irradiated ultrasound, and at least one evaluation unit for Evaluation of the recorded ultrasound. The device according to the invention is characterized in that a time signal of the switched-on ultrasound can be recorded for several paired combinations of the ultrasound transmitters and ultrasound receivers, with the evaluation unit being able to determine a speed of sound of at least one wave mode of the insonified ultrasound free of form echo based on the several recorded time signals.

Similar and equivalent advantages and configurations of the device according to the invention result from the method according to the invention.

According to an advantageous embodiment of the invention, the speed of sound is determined for a surface wave, in particular a Rayleigh wave or a creeping wave or a Lamb wave.

With the ultrasonic excitation several different wave modes develop. Typically these are Rayleigh waves and creeping waves. These have different speeds of sound (propagation speeds). The speeds of sound of these different wave modes are advantageously determined. This advantageously enables simultaneous determination of the speeds of sound (propagation speeds) of the longitudinal wave modes, shear wave modes and Rayleigh wave modes.

Here, the waves or wave modes mentioned can preferably represent a side effect (“dirty effect”) when used or excited with a vertical test head, in particular with a single oscillator and / or a phased array.

If the surface of the object is at least partially curved, that is to say the object is not planar, then dispersion effects of Rayleigh waves can also be taken into account.

Lamb waves are particularly excited in the case of coated and / or plate-shaped objects.

In an advantageous development of the invention, at least one material parameter of the object is calculated using the determined speed of sound.

The excited wave modes, for example Rayleigh waves and / or creeping waves and / or Lamb waves, have a different speed of sound, that is to say the speed of propagation, which is dependent on at least one material parameter of the object. By determining the speed of sound of at least one wave mode, preferably two wave modes, preferably a creep wave mode and a Rayleigh wave mode, the material parameter can advantageously be calculated.

For example, if c _{S is} the speed of sound in a shear wave mode, c _{R is} the speed of sound in a Rayleigh wave mode and v is the transverse contraction number of the object, then the approximate relationship c _R ≈ c _S (0.87 + 1.12 ν) / (1 + ν) applies. In other words, c _R / c _S = f (ν), so that the material parameter, in this example the Poisson's ratio v, can be calculated from the ratio of the determined sound velocities c _R and c _S. Typically the speeds of sound c _R , c _S and the longitudinal wave speed c _L (speed of sound of a Longitduinal wave) are interdependent, in the sense that a function with F (c _R , c _S , c _L ) = 0 exists. One or more material parameters can be calculated from this.

Advantageously, by determining several sound velocities associated with different wave modes of the ultrasound, different material parameters of the object, in particular its modulus of elasticity, its Poisson's ratio, its modulus of shear and / or its mass density can be calculated and determined. These can also be location-dependent with regard to the object.

According to an advantageous embodiment of the invention, the at least one material parameter is calculated by a mathematical model which determines a dependence of the determined speed of sound on the at least one material parameter.

The material parameter can be calculated based on the mathematical model by means of a compensation calculation and / or an optimization method and / or an estimation method, for example a linear regression.

A mathematical model, for example, quantifies the relationship between different speeds of sound and the material parameters.

wobei c_K die Schallgeschwindigkeit einer Kriech-Wellenmode des Objektes, E das Elastizitätsmodul des Objektes und ρ die Massendichte des Objektes bezeichnet.For example, the relationship or the mathematical model applies to creeping waves or longitudinal waves $$c_K^2=c_{\mathrm{L.}}^2=\frac{\mathrm{E.}\left(1-v\right)}{\rho \left(1+v\right)\left(1-2v\right)}$$

where c _{K is} the speed of sound in a creeping wave mode of the object, E is the modulus of elasticity of the object and ρ is the mass density of the object.

wobei G das Schubmodul des Objektes bezeichnet.The mathematical model also applies to the shear wave speed $$c_s=\sqrt{\frac{\mathrm{E.}}{\rho }\frac{1}{2\left(1+v\right)}}=\sqrt{\frac{G}{\rho }}$$

where G denotes the shear modulus of the object.

In other words, the Poisson's ratio, the mass density, the modulus of elasticity, the shear modulus or the compression modulus of the object are advantageously calculated as material parameters according to the mathematical model.

In an advantageous development of the invention, at least two sound speeds of two different wave modes, in particular a Rayleigh wave and a creeping wave, are determined, and the at least one material parameter of the object is calculated using the two sound speeds.

A calculation of several material parameters is preferably provided.

According to an advantageous embodiment of the invention, based on the determined material parameters, a mix-up check with regard to the object is carried out.

In other words, depending on the calculated material parameters, it is automatically checked whether the ultrasonic test is based on the intended object to be tested. This is preferably done automatically before the ultrasonic test. This can advantageously reduce the likelihood of confusing different objects.

In an advantageous development of the invention, an ultrasonic test based on the adjustment and / or calibration is carried out.

In other words, the adjustment and / or calibration according to the present invention and / or one of its configurations preferably takes place before the ultrasonic test of the object. This is particularly preferably done in an automated manner at the beginning of the ultrasonic test. In other words, an ultrasonic test according to the invention comprises an adjustment and / or calibration according to the present invention and / or one of its configurations. This advantageously makes the adjustment and / or calibration an integral part of the ultrasonic test.

According to an advantageous embodiment of the invention, the speed of sound or the speeds of sound are determined from time signals of the wave mode from the respective position of the ultrasonic transmitter to the respective position of the ultrasonic receiver.

This advantageously improves the adjustment and / or calibration.

In an advantageous further development of the invention, the speed of sound or the speeds of sound are determined by means of a geodetic distance between the respective position of the ultrasonic transmitter and the respective position of the ultrasonic receiver.

The geometric center of gravity / center of area of the ultrasonic transmitter and / or ultrasonic receiver can be used for this purpose. The surface of the object can be curved at least in a partial area. It is advantageous here not to use the Euclidean distance between the elements mentioned (ultrasonic transmitter and ultrasonic receiver), but rather the geodetic distance between the elements along the surface. The geodetic distance can be determined using the Riemannian metric of the surface within the framework of the Riemannian geometry.

According to an advantageous embodiment of the invention, the speed of sound or the speeds of sound are determined by means of a simulation of the propagation of the insonified ultrasound.

This can be done through a comparison with the simulation. In other words, the propagation of the ultrasound, including the excitation of several wave modes, is simulated. It is therefore advantageous if the simulation is designed to take into account the various wave modes that develop during the excitation, in particular Rayleigh waves, creeping waves and / or Lamb waves. In other words, the simulation includes the excitation of several ultrasonic modes (wave modes).

The device according to the present invention preferably has a transmit / receive test head, the transmit / receive test head comprising the ultrasonic transmitter and the ultrasonic receiver.

This advantageously enables a spatially compact examination of the object.

The device preferably comprises a test head designed as a transducer.

As a result, the test head is advantageously designed as an ultrasonic transmitter and as an ultrasonic receiver. In particular, the test head is designed as a piezo test head.

The ultrasonic transmitter or the transmit / receive test head is particularly preferably designed as a phased array test head and / or as a laser-ultrasound excitation unit.

This advantageously enables geometrical complex objects to be checked.

In an advantageous development of the invention, the determined speed of sound or the determined speeds of sound are determined by evaluating a plurality of time signals using a compensation calculation and / or an optimization method and / or an estimation method.

According to an advantageous embodiment of the invention, the lead time of a test head provided for the ultrasonic test is determined.

In an advantageous embodiment of the invention, a third sound speed, in particular a transverse wave, is determined from at least two sound speeds, in particular from the sound speed of a creeping wave and the sound speed of a Rayleigh wave, and is used for the adjustment and / or calibration.

Further advantages, features and details of the invention emerge from the exemplary embodiments described below and with reference to the drawing. The single FIGURE shows a schematic flow diagram of a method according to an embodiment of the present invention.

In a first step S1 To adjust and / or calibrate an ultrasonic test of an object, ultrasound is sounded into the object by means of N ≥ 2 ultrasonic transmitters.

In a second step S2 at least a part of the ultrasound is recorded by means of N ≥ 2 ultrasonic receivers.

The ultrasonic transmitters and ultrasonic receivers can preferably be used or provided for ultrasonic testing of the object.

Furthermore, the ultrasonic transmitter and the ultrasonic receiver can be arranged at different locations around the object. Alternatively, a transmit / receive test head can comprise the ultrasound transmitter and the ultrasound receiver and / or the test head can be designed as an ultrasound transmitter and ultrasound receiver, so that the ultrasound transmitter and the ultrasound receiver are arranged essentially at the same location or at the same location. The ultrasonic transmitter and / or the ultrasonic receiver and / or the transceiver test head can be moved with respect to the object, a new test being carried out at each location. As an alternative or in addition to this, the object can move.

In a further embodiment, at least one ultrasonic transmitter and at least N ≥ 2 ultrasonic receivers can be used. Furthermore, at least N 2 ultrasonic receivers and at least one ultrasonic transmitter can alternatively be used. N ≥ 2 ultrasonic transmitters and N 2 ultrasonic receivers are preferably used.

In a third step S3 a time signal of the sonicated ultrasound is recorded for several paired combinations of the ultrasonic transmitter and ultrasonic receiver.

For N 2 ultrasonic transmitters and N 2 ultrasonic receivers, N ² time signals are preferably recorded, that is to say a time signal for each paired combination.

In a fourth step S4 a speed of sound (speed of propagation) of at least one wave mode of the insonified ultrasound is determined based on the plurality of acquired time signals.

By determining the speed of sound, an improved adjustment and / or calibration can advantageously be provided for an ultrasonic test of the object. In particular, the adjustment and / or calibration becomes an integral part of the ultrasonic test, especially since the same ultrasonic transmitters and ultrasonic receivers can or are used for this purpose and / or the adjustment takes place directly on the test object without a form echo being required for this.

The embodiment described below explains a determination of the speed of sound of a creeping wave and a Rayleigh wave according to an embodiment of the present invention.

The calibration before an ultrasonic measurement or ultrasonic test is fundamentally necessary in order to correctly determine the positions of defects in the component. In addition to the speed of sound of the material, this typically also requires the lead time of a probe used for the ultrasonic test. This typically corresponds to twice the time between an electrical transmission pulse and the entry of the ultrasound into the object. In other words, the surface (depth = 0 mm) is calibrated if the lead time is previously determined experimentally and taken into account in the ultrasonic test.

For example, a linear phased array probe is used with five elements equidistantly spaced. Becomes element 1 pulsed, a creeping wave mode propagates on the surface, for example in the x direction, followed by a slower Rayleigh wave mode. Both wave modes are recorded by elements two to five at certain sound propagation times. If a regression line is drawn through the corresponding measured values, for example y = kx + d, then the sound velocities c _K and c _R result from the slope k. The lead time of the test head results from the axis section d.

Although the invention has been illustrated and described in more detail by the preferred exemplary embodiments, the invention is not restricted by the disclosed examples or other variations can be derived from them by the person skilled in the art without departing from the scope of protection of the invention.

List of reference symbols

S1

first step

S2

second step

S3

Third step

S4

fourth step

Claims (15)

Method for adjusting and / or calibrating an ultrasonic test of an object in which ultrasound is insonified into the object by means of N ≥ 2 ultrasound transmitters and / or in which at least part of the insonified ultrasound is detected by means of N ≥ 2 ultrasound receivers, characterized in that for a plurality of paired combinations of the ultrasonic transmitter and ultrasonic receiver each time a time signal of the ultrasound is recorded, and based on the plurality of recorded time signals, a speed of sound of at least one wave mode of the ultrasound is determined without form echo. Procedure according to Claim 1 , characterized in that the speed of sound for a surface wave, in particular a Rayleigh wave or a creeping wave or a Lamb wave is determined. Procedure according to Claim 1 or 2 , characterized in that at least one material parameter of the object is calculated by means of the determined speed of sound. Procedure according to Claim 3 , characterized in that the Poisson's ratio, the mass density, the modulus of elasticity, the modulus of shear or the modulus of compression of the object are calculated as material parameters. Procedure according to Claim 3 or 4th , characterized in that the at least one material parameter is calculated by a mathematical model which determines a dependence of the determined speed of sound on the at least one material parameter. Method according to one of the Claims 3 to 5 , characterized in that at least two sound speeds of two different wave modes, in particular of a Rayleigh wave and a creeping wave, are determined, and that at least one material parameter of the object is calculated using the two sound speeds. Method according to one of the Claims 3 to 6 , characterized in that based on the determined material parameters, a mix-up check is carried out with regard to the object. Method according to one of the preceding claims, characterized in that an ultrasonic test based on the adjustment and / or calibration is carried out. Method according to one of the preceding claims, characterized in that the speed of sound is determined from time signals of the wave mode from the respective position of the ultrasonic transmitter to the respective position of the ultrasonic receiver. Procedure according to Claim 9 , characterized in that the speed of sound is determined by means of a geodetic distance between the respective position of the ultrasonic transmitter and the respective position of the ultrasonic receiver. Procedure according to Claim 9 or 10 , characterized in that the speed of sound is determined by means of a simulation of the propagation of the sounded ultrasound. A device for adjusting and / or calibrating an ultrasonic test of an object, comprising at least N ≥ 2 ultrasonic transmitters for irradiating ultrasound into the object, and / or at least N ≥ 2 ultrasonic receivers for detecting at least part of the irradiated ultrasound, and at least one evaluation unit for evaluating the detected ultrasound, characterized in that a time signal of the switched-on ultrasound can be recorded for several paired combinations of the ultrasonic transmitters and ultrasonic receivers, with the evaluation unit being able to determine a sound speed of at least one wave mode of the ultrasound without form echo based on the several recorded time signals. Device according to Claim 12 , characterized in that it has a transceiver test head, the transceiver test head comprising the ultrasonic transmitter and the ultrasonic receiver. Device according to Claim 12 or 13 , characterized in that it has a test head designed as a transducer. Device according to one of the Claims 12 to 14th , characterized in that the ultrasonic transmitter is designed as a phased array probe and / or as a laser-ultrasonic excitation unit.

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