WO1995010023A1

WO1995010023A1 - Non-destructive inspection method for mechanical behaviour of article

Info

Publication number: WO1995010023A1
Application number: PCT/JP1993/001423
Authority: WO
Inventors: Sanichiro Yoshida
Original assignee: Kabushikigaisya Hutech; Rossiyskiy Materialovedcheskiy Centr
Priority date: 1993-10-05
Filing date: 1993-10-05
Publication date: 1995-04-13
Also published as: AU4834993A

Abstract

This invention contemplates to provide a method of executing a non-destructive inspection by a speckle method even when an object of inspection has rigid-body motion. The present invention uses a first camera (15) for measuring the total displacement quantity of an object and a second camera (21) for measuring the displacement quantity of the object due to a rigid-body motion by monitoring a reference point in the object. The displacement quantity due to rigid motion is subtracted from the total displacement quantity to obtain a displacement quantity reflecting only the displacement quantity resulting from deformation as a speckle pattern. The method of the present invention can obtain only the displacement quantity resulting from deformation by offsetting the displacement quantity of the object due to a rigid-body motion.

Description

Description Nondestructive inspection method for mechanical behavior of objects (Technical field)

The present invention relates to a method for inspecting materials and structures, and more particularly to a method for non-destructively inspecting the mechanical behavior of a loaded object.

(Background technology)

Conventionally, a coherent laser beam was applied to a loaded object before and after loading to obtain a pair of superimposed speckle patterns, which were then loaded. Methods for determining the stress and strain of an object are known. In this method, the speckle pattern obtained by the above method is converted into a diffraction pattern and subjected to mathematical processing. From the amplitudes obtained by this mathematical process, the stress and strain values at each point of the body undergoing elastic deformation are calculated (see, for example, PCT87 / 07365).

However, the above method is not set for the purpose of obtaining the three-dimensional plastic deformation wave, so it cannot be applied to the analysis of the plastic deformation process. In other words, the stress and strain fields in the elastic region can be calculated from the displacement obtained during the inspection, but the plastic flow analysis cannot be performed. Therefore, the above method is only applied to the evaluation of elastic deformation and is not substantially suitable for analyzing the region of plastic deformation.

On the other hand, the dynamics of deformation is extremely important in various application fields, especially for non-destructive inspection of mechanical behavior of an object. In all cases, local plastic deformation occurs in the material prior to the fracture of the externally loaded material. is there. Therefore, the lack of an appropriate approach to the problem of plastic deformation dynamics has long been a problem.

Other conventional methods, such as those that clarify the contribution of various plastic deformations to the actual process and fracture of plastic flow in materials ("Experimental Mechanics Handbook", edited by AS Kobayashi, Plenty Su Hall, 1987 (Handbook on Experimental mechanics, Ed. By AS Kobayashi Prentice-Hall Inc. 19

87)). These methods are all based on microscopic observation of the defect structure of the deformed material and are generally performed after the load has been removed. Many of these methods use optical microscopy, electron microscopy, X-ray structural analysis, and various micromechanical methods.

However, these methods have drawbacks such as requiring a great deal of labor, requiring complicated equipment, and requiring extremely localization of the inspection area due to the use of a high-resolution technique. The biggest drawback is that these methods can only be applied to defects remaining in the material, and cannot analyze the occurrence and motion of defects.

The most widely adopted method for obtaining data on material reliability indicators (see, e.g., R. A. Collakot, Structural Integrity Monitoring, London, Chipman and Hall, 1985) (See Collacott RA "Structual Integrity Monitoring", London, Chapman and Hall, 1985) consists of mechanical testing under various loading conditions (tension, compression, bending, torsion, crack sample testing, etc.) Properties such as elasticity, yield limit, ultimate strength, stress strength coefficient, fracture toughness, ultimate fatigue and long-term strength can be obtained.

These tests are generally performed on specially prepared and pre-adjusted samples of shape and dimensions. The strength and plasticity data obtained in this way are used to calculate the strength of mechanical parts and structures, as well as to calculate reliability characteristics. This type of method is problematic in that it requires the use of a combination of special mechanical properties and failure criteria for each test item. That is, these properties for the various test items are not related to each other, and their physical interpretations are based on models that contradict and often exclude each other. It is done.

Another drawback of this type of method relates to the problem of applying mechanical property data obtained under laboratory conditions to mechanical parts actually used in the field. In other words, the mechanical parts or actual machines operating in the field are usually under more complex stress conditions than in the inspection stage. In addition, the mechanical properties data of actual materials are greatly affected by surface conditions and environment. In consideration of this, even if an attempt is made to take into account the effects of the actual equipment at the inspection stage, only the inspection equipment and the inspection process become very complicated, and under such conditions, appropriate data cannot be obtained. ,.

Finally, the mechanical properties obtained by the above inspection are essentially averaged over the entire test sample. This poses a problem when trying to describe the properties of polycrystals with special interfaces or composites with different elastic moduli and strength properties.

One of the problems common to all of these existing plastic material testing methods is that they do not adequately record the evolution of plastic deformation and therefore predict the location of future fractures. That is not possible.

In order to solve the above-mentioned problems, a new and fundamentally new plastic deformation analysis method that can locally analyze the dynamics of deformation and predict the behavior of the actual machine under various load conditions is proposed. It needs to be established.

The present applicant has established such a new theoretical system which is the basis of the analytical method (for example, "Structural level of plastic deformation and fracture", Vyi-I-Panin et al., Bobo Sibirsk, Now force 1990, (see "Structual levels of plastic strain and destruction", VE Paninn et al, Bovosibirsk, Nauka, 1990). The essence of this method of analyzing the mechanical behavior of a body is based on the wave theory of plastic deformation. According to this wave theory, plastic deformation and the resulting destruction are wave-like, and their parameters (wavelength, amplitude, propagation velocity), material properties and load at that time Depends on conditions. Changes in these wave parameters indicate that a structural change has occurred in the material.

In addition, the applicant of the present application paid attention to the fact that the characteristics of the wave pattern were strong and characteristically changed when the test object to which the load was applied was close to destruction, and was first submitted on January 19, 1993. The effective non-destructive inspection method is disclosed in Japanese Patent Application No. 5—2 3 773 “Non-destructive inspection method of mechanical behavior of object and its device”. In other words, when the test object is close to breaking, the wavelength will be on the order of the sample size, the velocity will be zero, and the waves will be concentrated in two local vortices with opposite angular velocities. As a result, the wave patterns of plastic deformation at various stages of deformation have a lot of information, and the yield limit, ultimate strength, and processing of plasticity, strength, reliability, and fracture of materials and structures are improved. Gives new judgment conditions that are different from the conventionally used mechanical characteristics such as the curing coefficient. At that time, it is extremely important that the judgment conditions for plasticity, strength, and reliability can be handled in a unified manner regardless of the type of plastic material and load conditions. This approach allows plastic deformation and the resulting failure to be treated as different stages of the same process.

"Structural levels of plastic deformation and fracture," Vyi Panin et al., Bobosi Birsk, Now Power, 1990 ("Suctual levels of plastic strain and destruction", VE Pan in et al,. (Novosibirsk, Nauka, 1990) '', the present inventors found the wave nature of plastic deformation, systematized it theoretically, and conducted experimental studies on simple loads. I have. According to this method, an object to be analyzed is irradiated with a coherent laser beam, and is applied to a photographic plate. Copy. Then, after the object is deformed, the second irradiation is performed on the photographic plate without moving the plate. Thereafter, the photographic plate is chemically treated, and the information on the plastic displacement recorded in the photographic plate is decoded by speckle photography point scanning using a fine laser beam. Then, the parameters of the Young band diffraction pattern at each point are measured, and the absolute value of the displacement vector between two irradiations is determined from the band interval.

Furthermore, by taking the spatial derivative with respect to the coordinate axes, the components of the strain tensor, for example, the shear component,

£ xy = l / 2 (Δ u / Δ y + Δ ν / Δ x)

And rotational displacement

ω z = 1/2 (Δ u Ζ Δ y— △ ν Ζ Δ χ)

Is obtained.

The consistent distribution of the plastic strain tensors £ xy and ωz in the body is a relaxation wave of plastic deformation.

The idea of predicting the destruction of an object by analyzing wave parameters is based on the above-mentioned "structural level of plastic deformation and destruction", Vyi Panin et al., Bobosibi Norescu, Now Force, 1990 (" Structual levels of plastic strain and destruction ", VE Panin et al., Novosibirsk, Nauka, 1990). However, at the time of this writing, no study had been made on the law of the relaxation wave of plastic deformation evolving with the degree of deformation, nor on the relationship between deformation and the resulting fracture. In addition, the quantification of the criterion for destruction by wave parameters under various load conditions has not been established. Therefore, at that time, it was not possible to nondestructively examine the behavior of the loaded object by analyzing the wave pattern. In view of this point, the applicant of the present application disclosed in Japanese Patent Application No. 5-237377 “Non-destructive inspection method and apparatus of mechanical behavior of an object”, a three-dimensional wave of relaxation wave of plastic deformation. A non-destructive inspection method and an apparatus for mechanical behavior of an object, which can obtain a dynamic pattern and evaluate a rate of change of a plastic strain tensor both during a test and during an operation, are disclosed.

However, when the nondestructive inspection of the mechanical behavior of an object is performed by the method described in Japanese Patent Application No. 5-237373, if the object to be inspected moves as a rigid body, It becomes impossible to distinguish whether the displacement of each point measured is due to deformation. Therefore, the above method could not be applied to the case where the object to be inspected caused a rigid body motion during measurement, such as an engine.

The present invention has been made in view of the above-mentioned problems of the prior art, and the purpose of the present invention is to solve the above problem even when the object to be inspected moves rigidly at the time of measurement. An object of the present invention is to provide a new and improved method capable of performing a nondestructive inspection by a speckle method as described in 37773.

(Disclosure of the invention)

To solve the above problems, according to a first aspect of the present invention,

A first step of obtaining a first optical pattern of an inspection object to which a load is applied from the outside at a certain point in time by the first imaging means, and obtaining reference position information of a reference point of the inspection object by the second means; When;

At the same time as obtaining the second optical pattern of the inspection object after a lapse of a predetermined time from the certain point in time by the first imaging means, the displacement position information of the reference point of the inspection object at that point in time is obtained by the second A second step of obtaining by means of:

The reference position information and the displacement position of the reference point obtained by the second means A third step of superimposing information to obtain a displacement amount of the test object as a rigid body, and the first optical pattern and the second optical pattern obtained by the first imaging means. A fourth step of superimposing and superimposing the displacement of the object as a rigid body obtained in the third step in advance, and canceling the displacement;

A fifth step of obtaining a diffraction pattern including a parameter characterizing plastic deformation of the inspection object from the superimposed pattern obtained in the fourth step;

A sixth step of obtaining, from the diffraction pattern obtained in the fifth step, a parameter characterizing a plastic flow due to plastic deformation generated in the inspection object subjected to an external load;

By processing the parameters obtained in the sixth step, a relaxation wave of plastic deformation, which is a temporal and spatial distribution of deformation and rotational displacement speeds due to plastic deformation generated in the inspection object, is characterized. A seventh step of obtaining a wave pattern including wave parameters to be added;

An eighth step of determining the mechanical behavior of the inspection object loaded from outside based on a predetermined change appearing in the wave pattern obtained in the seventh step. A method for non-destructive testing of the mechanical behavior of a loaded object is provided.

Furthermore, according to a second aspect of the present invention,

A first step of obtaining a first optical pattern of an inspection object to which a load is applied from the outside at a certain point in time by the first imaging means, and obtaining reference position information of a reference point of the inspection object by the second means; When ;

The second optical pattern of the inspection object after a predetermined time has passed from the certain point A second step of obtaining the displacement position information of the reference point of the inspection object at that time by the second means at the same time as obtaining by the first imaging means;

A third step of superimposing the reference position information and the displacement position information of the reference point obtained by the second means to obtain a displacement amount of the test object as a rigid body, and the first imaging means The first optical pattern and the second optical pattern obtained by the above are superimposed, and a diffraction pattern of the total displacement of the inspection object is obtained from the superimposed optical pattern, and the diffraction pattern is obtained. A fourth step of obtaining the total displacement of the inspection object from

A fifth step of canceling the rigid displacement of the inspection object obtained in the third step from the total displacement amount of the inspection object obtained in the fourth step; obtained in the fifth step A parameter characterizing the plastic flow due to the plastic deformation generated in the inspection object to which an external load is applied, from the displacement amount due to the plastic deformation of the inspection object in which the displacement amount of the inspection object as a rigid body is offset. The sixth step of obtaining

An eighth step of determining the mechanical behavior of the test object loaded from outside based on a predetermined change appearing in the wave pattern obtained in the seventh step. A non-soil test method for the mechanical behavior of a loaded object is provided. As described above, according to the present invention, with respect to a point at which no apparent deformation occurs in the inspection object, for example, with the chuck portion of the tensile test device as a reference point, the movement of that point is recorded by the second means, By subtracting that amount from the displacement amount of the inspection object measured by the first imaging means, it is possible to offset the displacement amount due to the rigid body motion generated in the inspection object at the time of measurement. As a result, the nondestructive test using the speckle method described in Japanese Patent Application No. 5-237377 should be applied to inspection objects that generate rigid body motion during measurement, such as vibrating engines. Becomes possible.

(Brief description of drawings)

A description will now be given, with reference to the accompanying drawings, of a public example of a nondestructive test constructed based on the present invention.

In the accompanying drawings, FIG. 1 shows a configuration of a first inspection apparatus capable of performing the method of the present invention, and FIG. 2 shows a configuration of a second inspection apparatus capable of performing the method of the present invention. ing.

(Best mode for carrying out the invention)

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

First, in order to facilitate understanding of the method of the present invention, the principle of a nondestructive test of the mechanical behavior of an object by the scattering method on which the present invention is based will be briefly described. According to this principle, plastic deformation and the resulting fracture are determined by the deformation of the plastic deformation wave and the change in the rotational displacement velocity field. A plastic deformation wave is characterized as the process by which a plastic element event self-focuses into a single wave, referred to herein as a "relaxation wave of plastic deformation".

When the group velocity of the relaxation wave of plastic deformation decreases to zero, the resulting constant The standing wave degenerates into a pair of localized displacement vortices. At this time, the angular velocities of the vortices are opposite to each other, and the amplitude of rotation continuously increases. The result is a discontinuity at the vortex boundary that grows and leads to material destruction. This fact defines a new failure criterion based on the evolution of the group velocity of the relaxation wave of plastic deformation. This new determination condition can be applied to the nondestructive detection method for a loaded material body according to the present invention.

In other words, since the plastic deformation wave always appears as a three-dimensional wave on the surface of the object under load, the above-mentioned conditions for determining the fracture based on the zero group velocity of the relaxation wave of the plastic deformation are applied correctly. Therefore, it is essential to measure wave parameters in three-dimensional space. According to the present invention, the measurement of the wave parameters in the three-dimensional space is realized by superimposing the condensing hologram and processing the superimposed image.

The present applicant has already proposed in Japanese Patent Application No. 5-237377 a method for nondestructively inspecting the mechanical behavior of an inspection object to which an external load is applied based on this principle. ing. However, it is assumed that the inspection object itself is a static body, and when the inspection object itself performs a rigid body motion such as vibration, the displacement generated in the obtained optical pattern is It was not possible to identify whether the force was due to an externally applied load or to the rigid motion of the test object itself, so it could not be applied. The present invention has been made in view of such a problem, and makes it possible to apply the above method even when the inspection object itself is performing a rigid body motion.

Next, the configuration of one embodiment of the nondestructive inspection apparatus to which the method of the present invention can be applied will be briefly described.

The non-destructive inspection apparatus to which the method of the present invention can be applied comprises an arbitrary pulse laser apparatus 1 capable of irradiating a hologram medium with a predetermined pulse cycle and within 1 second. The optical system of this device has two optical paths. The first optical path is designed to form a collimated object beam, and comprises a reflecting mirror 2, a semi-transmitting mirror 3, a reflecting mirror 4, a beam expander 5, and a collimating lens 6. The second optical path is designed to generate a reference beam and comprises reflectors 2, 3 and reflectors 7, 8 and expander 9. Further, the optical system has an objective lens 10 for forming an object pattern on a carrier 11 (for example, a photographic plate) set in a holder (not shown). The holder can be moved in two mutually orthogonal directions for the purposes described below. As described above, a hologram of a focused image can be obtained by irradiating the carrier with light.

In addition, the system has an optical decoder consisting of reflectors 12 and 13 forming a 0.8 mm diameter beam that forms a diffraction pattern on the screen 14 through the hologram. The mathematical processing of the hologram obtained on the carrier 11 is performed in a computation unit consisting of an input and an analog / digital signal conversion system 15.

A digital output video camera can be used as the input and analog Z digital signal conversion system 15. The output of system 15 is connected to monitor 16 and to display 17.

In addition, the test apparatus is provided with a second video camera 21 for monitoring the inspection object 19 without any apparent deformation, for example, the chuck portion 20 of the tensile test apparatus. The video camera 21 has a flash light source 22. The light source 22 is emitted in synchronization with the pulse cycle of the pulse laser 1, and the displacement of the reference point of the inspection object 19 at that time is measured. It is possible. The output of the video camera 21 is also connected to the computer 17 where the output from the video camera 15 is output. Along with the force, a pre-processing described later is performed, and then, by a computer program programmed based on the above principle, the values of the speed of deformation and rotational displacement determined by the diffraction pattern actually generated on the inspection object are calculated, and It is possible to display the distribution of the velocity value on an axis in an arbitrarily set direction. Therefore, the output of the computer is the wave pattern of plastic deformation, and by observing its behavior, the deformation of the object can be predicted. The same wave pattern is reproduced by the plotter 18.

Next, a method for specifically applying the method of the present invention to the apparatus shown in FIGS. 1 and 2 will be described. First, an embodiment in which the method of the present invention is applied to a case where the displacement due to the rigid motion is substantially equal to the displacement due to the deformation will be described with reference to FIG.

The pulse laser output from pulse laser 1 is divided into two beams by the optical system. The first beam is an object beam, and after collimated, has the role of illuminating the image of the object 19 with a plane wave. The second beam is applied to the photographic plate 11 as reference light. The intensity ratio of the two beams is empirically selected by a transflective mirror 3 acting as a beam splitter.

The objective lens system 10 forms an image of the object 19 illuminated by the coherent light on the surface of the photographic plate 11. In this way, the first exposure is performed on the photographic plate 11 to create a speckle photograph. The exposure time is empirically determined. At the same time, a picture of the object is taken by the second camera 21 so that the reference point is included in the screen. At this time, since the photograph by the second camera is not used as a specklegram, it can be a normal photograph, and therefore, it is not necessary to use coherent light as a light source. However, the timings of the first camera 15 and the second camera 21 need to be accurately synchronized.

Then, a predetermined time △ t (for example, 40 to 80 seconds) elapses, and the object 19 is deformed. (Deformation depends on the applied load, changes in temperature and surrounding conditions, and other factors), and then the first camera 15 and the second camera 21 respectively use the same photo plate on the same photo plate. Perform the exposure of step 2 to create a double exposure photograph. At this time, of course, the double exposure photograph by the first camera is the power of a spectacle photograph, and the double exposure photograph by the second camera is a normal photograph.

The total displacement of the object to be inspected is calculated from the double-exposure speckle photograph obtained by the first camera 15 thus obtained. This total displacement includes not only the load from the outside (that is, the factor to be measured), but also the rigid motion of the test object itself, such as vibration. Therefore, according to the method of the present invention, the change in the position of the reference point recorded in the double exposure photograph by the second camera further indicates the displacement (vector) caused by the rigid motion of the inspection object itself. The displacement due to the rigid body motion is subtracted from the total displacement calculated above. In this way, the displacement amount (vector amount) actually generated on the inspection object due to the deformation can be obtained.

This series of processes is repeated at a new time interval or at the same time interval Δt. As a result, the entire process of deformation that actually occurred in the inspection object is obtained from a series of double-exposure holograms of the focused image.

Thus, the data of the velocity values of the displacement vectors at all points on the surface of the inspection object actually generated as a result of the deformation can be obtained from the double exposure holographic image. This data can be reconstructed by optically processing the resulting image. If the image is recorded on a photographic plate, first develop and fix the photographic latent image to obtain a negative film. Then, the hologram is placed in a holder and irradiated with the same reference beam used for recording. Along the axis perpendicular to the object surface, an object image consisting of the superposition of equidistant lines is input to the computer 1 by the system 15, and the displacement velocity component (5wZc5t) (in the Z-axis direction) is calculated. Is calculated. The observed image is Monitored on display 16.

The displacement velocity on the object surface (in the X and y directions) is determined by processing the speckle pattern of the object image. For this purpose, the double-exposure image is line-scanned every 1 mm by a thin beam formed by the reflectors 12 and 13. At this time, a so-called Young band diffraction pattern force is formed at each point. This pattern is recorded by the system 15 and digitized and input to the computer. In the computer, the band step d and the tilt angle with respect to the axis X are estimated.

Further, the value of the displacement velocity vector on the xy plane is calculated by the following equation.

r ~ = 1 ΖΔt

Furthermore, the tensor component of the plastic deformation rate of the object is calculated by the following equation.

In this specification, A is represented as S A <5 t, and A ′ is represented as A〜.

δ u / <5 t = r〜 cos Θ ヽ δ / δ t = r〜 sin θ

δ (ε χκ) / δ t = δ (δ u / δ t) / δ

δ (ε) / δ t = δ (δ W δ t) / δ,

δ (ε X)) / δ t = l / 2 {δ (δ u / δ t) / δ y + δ (δ / δ t) / δ χ}

δ (ωζ) / δt = l / 2 {δ (S / 6t) / δχ-δ (δu / δt) / δ}

S (£ xx) / c5t, (5 (£ yy) / 5t, δ (εxy) /δt.δ (ωζ) / 6t) obtained from the above equation are selected axes ( (E.g., in the direction of pull), and the plot is plotted on a plotter.The mechanical behavior of the object material is determined from the dynamic characteristics of the change. The analysis of the behavior of steel is based on the new theoretical and experimental criteria for strength and fracture established by the present inventors. However, a detailed description thereof will be omitted.

As described above, FIG. 1 shows an embodiment to which the method of the present invention is applied when the amount of displacement due to the rigid motion of the inspection object is substantially equal to the amount of displacement due to deformation, that is, when a diffraction pattern can be obtained on the same photographic plate. However, according to the present invention, when the displacement amount due to the rigid body motion of the inspection object is larger than the displacement amount due to the deformation, that is, when the diffraction pattern cannot be obtained on the same photographic plate, It can also be applied to

Next, the method of the present invention will be described with reference to FIG. 2 in the case where the amount of displacement due to rigid motion is larger than the amount of displacement due to deformation.

The basic configuration of the inspection device of FIG. 2 is the same as that of the inspection device of FIG. Therefore, components having the same functions are given the same reference numerals, and detailed description thereof will be omitted. However, the photo plate 11 of the inspection apparatus shown in Fig. 2 has a double structure, and the first plate 23 for taking the first speckle photograph and the first plate 23 for taking the second speckle photograph are taken. And a second plate 24. The first plate 23 and the second plate 24 are arranged so that the surfaces thereof are in close contact with each other, and are configured to be arbitrarily driven in the X, Υ, and Ζ directions by a driving device (not shown). ing.

First, similarly to the apparatus shown in FIG. 1, first exposure is performed using a first camera 15 to create a first speckle photograph on a first photographic plate 23. At the same time, a photograph of the inspection object is taken using the second camera 21 so that the reference point is included in the screen. At this time, also in the case of the present embodiment, since the photograph by the second camera is not used as a specklegram, the light source may be incoherent. However, as in the previous embodiment, it is necessary to accurately synchronize the shooting timing of both cameras. Then, a predetermined time △ t (for example, 40 to 80 seconds) elapses, and the object 19 is deformed. After that, the second shooting is performed by the first camera 15 and the second camera 21. At this time, the speckle photograph by the first camera 15 is not a double-exposure photograph as in the embodiment shown in FIG. It will be an independent second speckle photograph. However, in this case, the position of the first camera 15 is fixed without moving.

At the same time, an image is taken by the second camera 21, which is created as a double exposure photograph. This photograph may be a normal photograph as in the previous embodiment, and need not be a spec photo. In addition, as in the previous embodiment, the displacement caused by the rigid movement of the inspection object itself (based on the change in the position of the reference point recorded in the double exposure photograph by the second camera 21). Is calculated.

Next, the second camera plate 24 on which the second speckle photograph taken by the first camera 15 has been recorded is placed, and the photo holder 1 (not shown) is inserted into the second camera plate 21 by the second camera 21. The inspection object itself is spatially returned by a drive unit (not shown) by an amount of displacement as a rigid body motion obtained from a reference point recorded in the multiple exposure photograph. Furthermore, the first speckle photograph taken by the first camera 15 for the first time is converted into a second speckle photograph that has been moved at the initial position of the photo holder 1 so as to offset the amount of displacement due to rigid body motion. Superimpose. At this time, it is important that the two photographs are closely arranged so that a diffraction pattern can be obtained from the superimposed photograph. As a result, the difference in spatial position between the first speckle photograph and the second speckle photograph reflects only the amount of displacement due to deformation.

Further, the two superimposed photographs thus obtained can be decoded in the same manner as in the embodiment shown in FIG. 1 to obtain a young band. Since the decoding method and the analysis method are the same as those described above, a detailed description is omitted here. In the above embodiments, the method of the present invention is applied to the case where the displacement amount due to the rigid motion of the inspection object is approximately the same as the displacement amount due to the force deformation and the displacement amount due to the rigid motion is larger than the displacement amount due to the deformation. Although described with reference to FIGS. 1 and 2, the present invention is not limited to such an embodiment, and various changes and modifications can be made within the scope of the technical idea described in the claims. In addition, the explanation of the correction of the displacement of the rigid body motion in the XY plane has been described. However, if the displacement of the conductor motion in the Z direction is also to be corrected, a means for recognizing the reference point, such as a camera, may be used. By using a plurality of them, correction can be easily performed by performing three-dimensional signal processing by a conventional technique.

(Possibility of industrial use)

As described above, according to the method of the present invention, even when the inspection object itself moves rigidly at the time of measurement, the displacement amount due to the rigid movement can be offset, so that the speckle method is used. It is suitable for performing non-destructive inspection of the mechanical behavior of an object more easily.

Also, the method of the present invention can be applied to a machine under load such as a pressure vessel, a pipeline, a load structure, a power plant, various devices of a power plant, a chemical reactor, a steam boiler, a turbine, and a housing of an engine. It can be applied to the analysis of stress Z strain state of structures, structures and various devices. Further, the method and apparatus of the present invention are useful for research on the analysis of the mechanism of plastic deformation and fracture, evaluation of the reliability of new materials, and evaluation of the maximum allowable load.

Claims

(The scope of the claims)

(1) The first optical pattern at a certain point of the inspection object to which an external load is applied is obtained by the first imaging means, and the reference position information of the reference point of the inspection object is obtained by the second imaging means. A first step of obtaining by means;

A third step of superimposing the reference position information and the displacement position information of the reference point obtained by the second means to obtain a displacement amount of the test object as a rigid body, and the first imaging means A fourth step in which the first optical pattern and the second optical pattern obtained by the above are offset in advance by a displacement amount of the object as a rigid body obtained in the third step and then superimposed;

A fifth step of obtaining a diffraction pattern including parameters characterizing plastic deformation of the inspection object from the superimposed pattern obtained in the fourth step;

A sixth step of obtaining, from the diffraction pattern obtained in the fifth step, a parameter characterizing a plastic flow caused by plastic deformation occurring in the inspection object subjected to an external load;

Based on a predetermined change appearing in the wave pattern obtained in the seventh step, An eighth step of determining a mechanical behavior of the test object loaded from a part. A non-destructive test method for a mechanical behavior of a loaded object.

(2) The first optical pattern at a certain point in time of the inspection object to which a load is applied from the outside is obtained by the first imaging means, and the reference position information of the reference point of the inspection object is acquired by the second imaging means. A first step of obtaining by means;

A third step of superimposing the reference position information and the displacement position information of the reference point obtained by the second means to obtain a displacement amount of the test object as a rigid body, and the first imaging means The first optical pattern and the second optical pattern obtained by the above are superimposed, and a diffraction pattern of a picture displacement amount of the inspection object is obtained from the superimposed optical pattern, and a diffraction pattern thereof is obtained. A fourth step of obtaining the total displacement of the inspection object from

A fifth step of canceling the rigid displacement of the inspection object obtained in the third step from the total displacement amount of the inspection object obtained in the fourth step; obtained in the fifth step A parameter characterizing the plastic flow due to the plastic deformation generated in the inspection object to which an external load is applied, from the displacement amount due to the plastic deformation of the inspection object in which the displacement amount of the inspection object as a rigid body is offset. A sixth step of obtaining

By processing the parameters obtained in the sixth step, the inspection object A seventh step of obtaining a wave pattern including a set of wave parameters characterizing the relaxation wave of plastic deformation, which is a temporal and spatial distribution of deformation and rotational displacement speeds due to plastic deformation generated in the object;

An eighth step of determining the mechanical behavior of the test object loaded from the outside based on a predetermined change appearing in the wave pattern obtained in the seventh step, and a force. A non-destructive testing method for the mechanical behavior of a loaded object.