WO2015098010A1 - 複合材料内のポロシティ評価方法およびポロシティ評価装置 - Google Patents
複合材料内のポロシティ評価方法およびポロシティ評価装置 Download PDFInfo
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- WO2015098010A1 WO2015098010A1 PCT/JP2014/006147 JP2014006147W WO2015098010A1 WO 2015098010 A1 WO2015098010 A1 WO 2015098010A1 JP 2014006147 W JP2014006147 W JP 2014006147W WO 2015098010 A1 WO2015098010 A1 WO 2015098010A1
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Definitions
- the present invention relates to an evaluation method and evaluation apparatus for porosity remaining inside a fiber-reinforced resin composite material (a large number of dispersed microscopic void-like defects), and in particular, the total amount of porosity contained in the fiber-reinforced resin composite material
- the present invention relates to an evaluation method and an evaluation apparatus that can evaluate not only evaluation but also uneven distribution in the thickness direction of porosity.
- composite materials fiber reinforced resin composite materials
- CFRP carbon fiber reinforced plastic
- a molded product made of a composite material is formed by laminating a plurality of prepregs (a sheet made of a reinforcing fiber material impregnated with a matrix resin material, etc.), and the resulting laminate is obtained by an autoclave (pressure cooker). It is obtained by applying pressure and heating to cure.
- porosity a large number of minute void-like defects called “porosity” may be dispersed inside the composite material. If a certain amount or more of porosity exists in the composite material, it leads to a decrease in the structural strength of the composite material. In particular, when the composite material is used in the aerospace field, the demand for structural strength is severer than in other fields, so the amount of porosity needs to be reduced as much as possible. Therefore, when manufacturing a composite material, it is necessary to evaluate porosity nondestructively.
- an ultrasonic flaw detection method disclosed in Patent Document 1 or an ultrasonic flaw detection apparatus disclosed in Patent Document 2 can be cited.
- All of these technologies are aimed mainly at composite materials used in the aviation field.
- an ultrasonic wave is incident from the surface of the composite material (composite material) in the thickness direction, and a reflected wave reflected on the back surface or a transmitted wave measured on the back surface is measured.
- the defect of the composite material is inspected based on the attenuation degree of the transmitted wave or the attenuation characteristic of the reflected wave or the transmitted wave.
- the attenuation rate of the reflected wave basically depends on the total amount of porosity contained in the composite material. Therefore, in the technique disclosed in Patent Document 1 or 2, the distribution of the porosity is uniform or unevenly distributed. It is not possible to distinguish whether or not
- the present invention has been made in order to solve such problems, and provides a technique that can evaluate not only the total amount of porosity contained in a composite material but also the distribution in the thickness direction. Objective.
- the porosity evaluation method according to the present invention is obtained by laminating a plurality of prepregs and then curing, and using one surface of a composite material having a multilayer structure as an incident surface, The ultrasonic wave is incident in the thickness direction of the composite material, the reflected wave is received on the incident surface side, the received reflected wave is set as the total reflected wave, and the multilayer reflected wave is included in the total reflected wave.
- the total reflected wave is used to evaluate the distribution in the thickness direction of the porosity contained in the composite material by performing time-frequency analysis of the total reflected wave, This is a configuration for acquiring temporal change information of interlayer reflected waves.
- the temporal change information of the interlayer reflected wave can be obtained by performing the time-frequency analysis on the entire reflected wave. Since this change information includes information indicating the attenuation of the reflected wave derived from the porosity, the distribution in the thickness direction of the porosity in the composite material can be satisfactorily evaluated based on the change information. .
- the porosity evaluation method of the said structure it is used in order to evaluate the said porosity contained in the said composite material based on attenuation
- the incident frequency of the ultrasonic wave is a standard frequency
- the ultrasonic wave may be configured to have a higher incident frequency than the standard frequency.
- the incident frequency may be configured to be changeable according to the thickness of the ply that forms the composite material.
- the evaluation information is compared with the change information from the actually received interlayer reflected wave,
- the evaluation information is obtained by performing a numerical simulation that simulates the composite material including the modeled porosity and the incidence of the ultrasonic wave and the reception of the reflected wave on the composite material.
- the configuration may be such that at least one of the known information of the reflected wave is used.
- the change information obtained by the numerical simulation is evaluation information that well reproduces the features that appear in the change information obtained by time-frequency analysis of the actually measured interlayer reflected wave.
- the known information of the said interlayer reflected wave is the information for evaluation obtained from the test piece containing a known porosity. Therefore, by comparing these evaluation information with change information based on actual measurement, it becomes possible to estimate the distribution of porosity in the composite material more precisely.
- the porosity evaluation apparatus has a composite surface with respect to an incident surface, which is one surface of a composite material having a multilayer structure, obtained by laminating a plurality of prepregs and then curing them.
- An ultrasonic detector that receives ultrasonic waves in the thickness direction of the material and receives reflected waves from the incident surface, and the received reflected waves as total reflected waves are included in the total reflected waves In order to evaluate the distribution in the thickness direction of the porosity contained in the composite material by performing time-frequency analysis of the total reflected wave when the reflected wave from the interlayer interface of the multilayer structure is an interlayer reflected wave And a time-frequency analyzer that acquires temporal change information of the interlayer reflected wave.
- the porosity evaluation apparatus having the above configuration further includes a display information generator that generates display information from the change information, and a display that can display the change information using the display information. It may be a configuration.
- the porosity evaluation unit estimates the distribution of the porosity in the composite material by comparing the change information obtained from the time-frequency analyzer with the information for evaluation.
- the evaluation information at least one of the simulated change information of the interlayer reflected wave and the known information of the interlayer reflected wave of the composite material acquired in advance is used, and the simulated interlayer reflection is used.
- the change information of the wave is obtained by simulating the incidence of the ultrasonic wave and the reception of the reflected wave on the composite material including the modeled porosity by numerical simulation, and the known information Performs the incidence of the ultrasonic wave and reception of the reflected wave on a specimen of the composite material containing the known porosity It may be configured those obtained by the.
- the porosity evaluation apparatus having the above configuration includes at least one of an ultrasonic transmission / reception simulator that performs the numerical simulation and an evaluation information database that stores a plurality of pieces of the evaluation information, and the porosity evaluator includes the ultrasonic wave
- the configuration may be such that the evaluation information is acquired from at least one of a transmission / reception simulator and the evaluation information database.
- FIG. 1A is a schematic cross-sectional view showing an example of a healthy composite material that does not include porosity, and is an example of a defective composite material that includes porosity. It is a typical sectional view showing.
- FIG. 2 is a process diagram showing an example of a composite material porosity evaluation method according to Embodiment 1 of the present invention.
- FIG. 3A is a schematic diagram for explaining a reflected wave of an ultrasonic wave incident on a composite material for porosity evaluation
- FIGS. 3B and 3C are schematic diagrams for explaining attenuation of the reflected wave by the porosity.
- FIG. 4 is a block diagram schematically showing an example of a porosity evaluation apparatus for carrying out the porosity evaluation method shown in FIG. FIG.
- FIG. 5 is a block diagram showing a modification of the porosity evaluation apparatus shown in FIG.
- FIG. 6 is a process diagram showing an example of a composite material porosity evaluation method according to Embodiment 2 of the present invention.
- FIG. 7 is a block diagram schematically showing an example of a porosity evaluation apparatus for implementing the porosity evaluation method shown in FIG.
- FIG. 8 is a block diagram showing a modification of the porosity evaluation apparatus shown in FIG.
- FIG. 9 is a block diagram showing a modification of the porosity evaluation apparatus shown in FIG. 7 or FIG.
- FIG. 10 is a waveform diagram showing the result of the embodiment of the present invention and showing the waveform of the reflected wave obtained from the porosity evaluation sample.
- FIG. 11A to 11D are graphs showing the results of the embodiment of the present invention and the results of time-frequency analysis of the reflected wave obtained from the porosity evaluation sample.
- FIG. 12A and FIG. 12B are graphs showing the results of the embodiment of the present invention and showing the comparison between the result of time-frequency analysis of the reflected wave obtained from the porosity evaluation sample and the result of numerical simulation of the reflected wave It is.
- pority means “a large number of dispersed microscopic void-like defects” as described above.
- porosity may include the content of void-like defects, in this embodiment, “porosity” refers to the defects themselves.
- the composite materials 100A to 100C according to the present invention have a multilayer structure in which a plurality of plies 101 are laminated.
- Each ply 101 is basically composed of a fiber material which is a reinforcing material and a thermosetting resin composition which is a matrix material.
- the healthy composite material 100A shown in FIG. 1A is in an ideal state having no defects therein, but the defective composite material 100B shown in FIG. 1B or the defective composite material shown in FIG. 1C.
- Each of 100C includes a plurality of porosity 102 (a minute void-like defect) therein.
- the porosity 102 includes a porosity 102 ⁇ / b> A generated between the plies 101 and a porosity 102 ⁇ / b> B generated inside the ply 101.
- both of the porosity 102A and 102B are relatively dispersed, but in the defect composite material 100C shown in FIG. 1C, the porosity 102A and 102B are on one side. It is unevenly distributed.
- the composite materials 100A to 100C are respectively shown as flat members. However, this illustration is for convenience, and the composite material to be actually evaluated depends on its use. It is a molded product molded into various shapes according to the The “composite material” in the present embodiment refers not only to the composite material itself as the “material” but also to the “molded product made of the composite material” to be evaluated. In the following description, the term “composite material 100” is used when referring to “composite material” without distinguishing between the sound composite material 100A and the defective composite materials 100B and 100C.
- the composite material 100 is generally manufactured by laminating (ply-up) prepregs in a desired shape and then curing them by heating and pressing with an autoclave (pressure cooker).
- the prepreg is a semi-cured state obtained by impregnating a fiber material with a thermosetting resin composition.
- thermosetting resin used for the composite material 100 is not particularly limited, and is a thermosetting resin known in the field of composite materials such as epoxy resin, bismaleimide resin, vinyl ester resin, unsaturated polyester resin, phenol resin, silicone. Examples thereof include thermosetting resins such as resins. These resins may be used alone or in combination of a plurality of types as appropriate.
- thermosetting resin composition in the present embodiment includes not only a composition containing other components together with the thermosetting resin, but also a resin mixture comprising a plurality of types of thermosetting resins, or a single Types of thermosetting resins are also included.
- the fiber material used for the composite material 100 is not particularly limited as long as it can reinforce the molded product (composite material) obtained by using it together with the thermosetting resin composition.
- CFRP thermosetting resin composition
- carbon fiber is preferably used.
- the length, diameter, and the like of the fiber material are not particularly limited, and may be set as appropriate according to the use of the composite material 100.
- the ratio between the fiber material and the thermosetting resin composition is not particularly limited, and can be set as appropriate according to the application or use conditions. Furthermore, the composite material 100 may include other known materials in addition to the fiber material and the thermosetting resin composition.
- the composite material 100 according to the present invention is used in various fields such as sports equipment, industrial machines, vehicles, and aerospace, and its use is not particularly limited. Particularly typical applications include the aerospace field such as aircraft parts.
- the porosity evaluation method according to the present invention is a method that enables not only a total evaluation of the porosity 102 included in the composite material 100 but also an evaluation of distribution such as uneven distribution in the thickness direction.
- the defect composite material 100B shown in FIG. 1B and the defect composite material 100C shown in FIG. 1C differ in the distribution of the porosity 102 contained therein, but the total amount of the porosity 102 is substantially the same.
- the conventional evaluation method can evaluate the difference between the healthy composite material 100A and the defective composite material 100B or 100C, but the defective composite material 100B and the defective composite material 100C containing the same amount of porosity 102. It is practically difficult to evaluate the difference.
- the porosity evaluation method performs time-frequency analysis on the reflected wave of the ultrasonic wave incident on the composite material 100 as shown in FIG. Thereby, the distribution of whether or not the porosity 102 is unevenly distributed in the composite material 100 can be evaluated.
- the porosity evaluation method for example, assuming a defect composite material 100B or 100C having a three-layer structure shown in FIG. 3A and a defect composite material 100B or 100C having a five-layer structure shown in FIGS. 3B and 3C, schematically. explain.
- one surface (for example, the front surface) of the composite material 100 is the incident surface 103, the other surface (for example, the back surface) is the bottom surface 104, and the interface between the plies 101 is an interlayer interface 105 having a multilayer structure.
- the porosity 102 porosity 102B in FIGS. 1A and 1C
- the porosity 102 FIG. 1B and FIG. 1B
- the porosity 102A) in FIG. 1C is not shown.
- the reflected wave Wr received by the incident surface 103 includes the bottom surface reflected wave Wr1 and the interlayer reflected wave Wr2. Therefore, for convenience of explanation, all received reflected waves Wr are referred to as “total reflected waves Wr”.
- the total reflected wave Wr is a reflected wave of an ultrasonic wave received (detected) on the incident surface 103 side (position close to the incident surface 103) of the composite material 100, and as indicated by a thin broken line in FIG. 3A.
- the surface reflected wave Wr0 is also included.
- the surface reflected wave Wr0 is a reflected wave generated when the ultrasonic wave is reflected by the incident surface 103.
- the incident wave Wi, the bottom surface reflected wave Wr1, and the interlayer reflected wave Wr2 are also regarded as simple arrows, and are all illustrated by thick broken lines.
- 3A to 3C the angles formed by the incident wave Wi and the reflected waves Wr0, Wr1 and Wr2 are also shown for convenience, and do not represent actual ultrasonic behavior.
- the interlayer reflected wave Wr2 is reflected between the first layer and the second layer ply 101 reflected from the interlayer interface 105 and the second layer and the third layer ply 101 between the layers. Two of those reflected at the interface 105 are shown. Among these, the latter interlayer reflected wave Wr2 is illustrated by meandering dotted arrows, assuming that a part thereof is scattered and attenuated by the porosity 102 existing in the ply 101 of the second layer. The illustration of the attenuated interlayer reflected wave Wr2 is the same in FIGS. 3B and 3C.
- 3B and 3C both show the defect composite material 100B in which the porosity 102 is dispersed on the left side, and the defect in which the porosity 102 is unevenly distributed on the incident surface 103 side on the right side.
- a composite material 100C is illustrated. In both FIG. 3B and FIG. 3C, only two of the porosity 102 are shown on the left and right sides.
- the porosity 102 is illustrated in a second layer ply 101 from the top and a second layer ply 101 from the bottom (fourth layer from the top).
- the defect composite material 100C the second layer ply 101 is shown from the top and the third layer ply 101 is shown from the top.
- an ultrasonic wave is incident from the incident surface 103 toward the thickness direction of the composite material 100 (see the incident wave Wi in FIG. 3A), and the total reflection of the ultrasonic wave from the incident surface 103.
- the wave Wr is received (step S11).
- time-frequency analysis of the received total reflected wave Wr is performed to obtain temporal change information of the interlayer reflected wave Wr2 included in the total reflected wave Wr (step S12).
- the distribution of the porosity 102 is evaluated about the thickness direction of the composite material 100 (process S13).
- the porosity 102 is evaluated based on the attenuation rate (or attenuation characteristics, etc.) of the bottom surface reflected wave Wr1, so that only a substantially total evaluation can be performed.
- the bottom surface reflected wave Wr1 is partially scattered and attenuated by the two porosities 102 and reaches the incident surface 103.
- the attenuation rate of the bottom surface reflected wave Wr1 reflects the total amount in the thickness direction of the composite material 100, but does not sufficiently reflect the difference in distribution in the thickness direction. Therefore, it is not possible to perform an evaluation considering the distribution of the porosity 102 in the thickness direction only by the attenuation rate of the bottom surface reflected wave Wr1. That is, when only the attenuation rate of the bottom surface reflected wave Wr1 is measured, the difference between the defect composite material 100B in which the porosity 102 is dispersed and the defect composite material 100C unevenly distributed on the incident surface 103 side cannot be sufficiently evaluated. It will be.
- the schematic example shown in FIG. 3C shows the interlayer reflected wave Wr2 reflected by the interlayer interface 105 between the third layer and the fourth layer.
- the interlayer reflected wave Wr2 is not scattered by the porosity 102 on the bottom surface 104 side, but only by the porosity 102 on the incident surface 103 side. It corresponds to one porosity 102.
- the defect composite material 100 ⁇ / b> C on the right side the interlayer reflected wave Wr ⁇ b> 2 is scattered by the two porosities 102 on the incident surface 103 side, and the attenuation rate thereof corresponds to the two porosities 102. Therefore, in the example shown in FIG. 3C, the interlayer reflected wave Wr2 of the defective composite material 100C has a higher attenuation factor than the interlayer reflected wave Wr2 of the defective composite material 100B.
- the interlayer reflected wave Wr2 is generated not only at the interlayer interface 105 between the third layer and the fourth layer but also at the interlayer interface 105 between each of the first layer to the fifth layer. Further, the actual interlayer reflected wave Wr2 does not propagate as a simple arrow as shown in FIGS. 3B and 3C, but propagates while repeating reflection and transmission at each interlayer interface 105 of the defective composite material 100B or 100C. .
- the total reflected wave Wr is subjected to time-frequency analysis, it is possible to capture temporal changes of individual frequency components constituting the total reflected wave Wr. Therefore, if the temporal change (attenuation) of the frequency component corresponding to the interlayer reflected wave Wr2 is acquired as change information, the distribution of the porosity 102 in the thickness direction of the defective composite material 100B or 100C can be obtained from this change information. It becomes possible to evaluate.
- the change information is not particularly limited as long as it is information obtained as a result of the time-frequency analysis and can evaluate the distribution of the porosity 102.
- sustained vibration in a characteristic frequency range is acquired as change information. This frequency range differs appropriately depending on the structure of the composite material 100 (number of layers, layer thickness, shape as a molded product, etc.), and is not limited to a specific frequency range.
- the composite material 100 is schematically illustrated as a five-layer structure, but the actual composite material 100 has a multilayer structure of several tens to hundreds of layers. Therefore, when an ultrasonic wave is incident on the composite material 100 having such a multilayer structure, an interlayer reflected wave Wr2 is generated at each of a large number of interlayer interfaces 105. As a result, compared to the bottom surface reflected wave Wr1 generated only at the bottom surface 104, the interlayer reflected wave Wr2 is generated entirely in the thickness direction of the composite material 100, and thus the attenuation rate varies. If such an interlayer reflected wave Wr2 can be used, change information including the state of each layer constituting the multilayer structure can be acquired. Since abundant information can be obtained by this, it becomes possible to evaluate the distribution of the porosity 102 in the composite material 100 in more detail.
- the frequency of the ultrasonic wave is not particularly limited, and a known frequency range can be selected in the field of ultrasonic flaw detection.
- the interlayer reflected wave Wr2 is focused on, so that a frequency region that easily receives the interlayer reflected wave Wr2 on the incident surface 103 is selected. It is preferable.
- the incident frequency of the conventional porosity evaluation method (the frequency used for evaluating the porosity 102 based on the attenuation of the bottom surface reflected wave Wr1 in total) is, for example, “standard frequency”, the present invention.
- the incident frequency of the porosity evaluation method according to the above may be set higher than the standard frequency.
- the bottom surface reflected wave Wr1 from the bottom surface 104 or the good interlayer reflected wave Wr2 from the interlayer interface 105 close to the bottom surface 104 may not be obtained.
- priority should be given to receiving the interlayer reflected wave Wr ⁇ b> 2 from the interlayer interface 105 close to the incident surface 103. Therefore, it is possible to select and set the incident frequency as a higher frequency range than before.
- the incident wave Wi is scattered and attenuated by the porosity 102 positioned in front of the incident surface 103 to become an interlayer reflected wave Wr2. Therefore, in the present invention, as described above, priority may be given to obtaining the interlayer reflected wave Wr2 close to the incident surface 103 side. On the contrary, when the incident frequency is set low in order to obtain the interlayer reflected wave Wr1 or the interlayer reflected wave Wr2 from the interlayer interface 105 near the bottom surface 104, a good interlayer reflected wave Wr2 is generated from the interlayer interface 105 near the incident surface 103. There is a possibility that it cannot be received.
- the incident frequency at which the interlayer reflected wave Wr2 can be satisfactorily received from each interlayer interface 105 may be set according to the thickness of the ply 101 constituting the composite material 100. To what extent the interlayer reflected wave Wr2 can be received in the thickness direction of the composite material 100 is determined by conditions such as the material of the composite material 100. For example, if the interlayer reflected wave Wr2 can be received to about half the depth, the interlayer reflected wave Wr2 can be received for the entire thickness of the composite material 100.
- the entire thickness of the composite material 100 is obtained.
- the distribution of the porosity 102 can be evaluated.
- the interlayer reflected wave Wr ⁇ b> 2 may be received with priority from the interlayer interface 105 close to the incident surface 103. Therefore, the bottom surface reflected wave Wr1 is basically an unnecessary reflected wave.
- a frequency region in which both the interlayer reflected wave Wr2 and the bottom surface reflected wave Wr1 can be received satisfactorily may be selected.
- the incident frequency can be changed according to the thickness of the ply 101 constituting the composite material 100. Since the composite material 100 to be actually evaluated is a molded product having a predetermined shape, the thickness (or the number of layers) may be different even for a single molded product. Therefore, by making it possible to change the incident frequency, it is possible to perform the porosity evaluation for the composite material 100 of various shapes or uses in a general purpose.
- the method of changing the incident frequency is not particularly limited, and the frequency of the ultrasonic wave used as the incident wave Wi may be set to a suitable frequency (a specific frequency is selected).
- a suitable frequency a specific frequency is selected.
- broadband ultrasonic waves including suitable frequencies according to various conditions may be used as the incident wave Wi. This point will be specifically described.
- the case where the interlayer reflected wave Wr2 is remarkably generated can be said to be a case where the phases of the interlayer reflected wave Wr2 from between the plies 101 (interlayer) in the composite material 100 are substantially aligned. Therefore, assuming a case where all of the interlayer reflected waves Wr2 from the respective layers are prepared, the conditions for this are schematically examined. If the ultrasonic propagation velocity in the thickness direction of the ply 101 is c, the thickness of the ply 101 is h, the frequency (incident frequency) of the incident wave Wi is f, and the wavelength of the incident wave Wi is ⁇ , c, h , F and ⁇ can be estimated as the following equation (1).
- the incident frequency f can be expressed as the following equation (2) using the ultrasonic wave propagation velocity c and the thickness h of the ply 101.
- the relatively wide-band ultrasonic wave including a frequency (preferable frequency) that satisfies the condition of Expression (2) as the approximate value described above as the incident wave Wi. May be selected and used. If such a broadband ultrasonic wave is incident on the composite material 100 and at least the interlayer reflected wave Wr2 is received and time-frequency analysis is performed, the interlayer reflected wave Wr2 is remarkably generated in the vicinity of a suitable frequency. Can be confirmed.
- the porosity evaluation apparatus 10A includes an ultrasonic detector 11, a time-frequency analyzer 12, a display information generator 13, and a display 14.
- the ultrasonic detector 11 includes a probe 111 and an ultrasonic transmitter / receiver 112, and uses one surface of the composite material 100 as an incident surface 103, and an ultrasonic wave is incident from the incident surface 103 in the thickness direction. At the same time, the entire reflected wave Wr from the incident surface 103 is received.
- a specific configuration of the ultrasonic detector 11 is not particularly limited, and a known configuration can be suitably used in the field of ultrasonic flaw detection.
- the incident frequency of the ultrasonic detector 11 can be changed.
- a plurality of types of probes 111 having different nominal center frequencies are prepared, and a suitable probe 111 may be appropriately replaced according to various conditions (material, thickness, etc.) of the composite material 100.
- the configuration (frequency adjuster) for changing the incident frequency may be provided in the ultrasonic transmitter / receiver 112, or the porosity evaluation apparatus 10 ⁇ / b> A may be provided separately from the ultrasonic transmitter / receiver 112.
- the probe 111 is shown in direct contact with the composite material 100, but usually a buffer material (delay material) is provided between the ultrasonic wave transmitting / receiving surface and the incident surface 103. Material).
- a buffer material delay material
- the specific kind of this buffer material is not specifically limited, Generally water is used also including the Example mentioned later. Therefore, the ultrasonic detector 11 should just be comprised so that an ultrasonic wave may be transmitted / received in the state which immersed the composite material 100 in water.
- a buffer material if it is a material which can receive the surface reflected wave Wr0 and the waveform of the interlayer reflected wave Wr2 following this, it will not necessarily be limited to water, A well-known resin material etc. may be sufficient.
- the time-frequency analyzer 12 performs time-frequency analysis on the total reflected wave Wr received by the ultrasonic detector 11 from the incident surface 103 of the composite material 100, so that the interlayer reflected wave Wr2 included in the total reflected wave Wr is analyzed. Get temporal change information. This change information is information used for evaluating the distribution in the thickness direction of the porosity 102 included in the composite material 100 as described above.
- the specific configuration of the time-frequency analyzer 12 is not particularly limited, and may be configured as a logic circuit using a known switching element, subtractor, comparator, or the like, or a known processor (CPU or the like) may be a storage device. A configuration realized by operating according to a program stored in (memory), that is, a functional configuration of a processor may be used.
- the specific method of time-frequency analysis is not particularly limited.
- a short-time Fourier transform (STFT) is adopted.
- the parameters for performing the STFT are not particularly limited, and in the embodiments described later, the time range for performing the STFT, the number of divisions of the time range, the type of the window function, the width of the window function, and the like are appropriately set. .
- the display information generator 13 generates display information from the change information obtained by the time-frequency analyzer 12.
- the specific configuration of the display information generator 13 is not particularly limited as long as it is a known processor (GPU or the like) for displaying an image on the display 14. Further, each of the time-frequency analyzer 12 and the display information generator 13 may have a functional configuration in which one processor operates according to a program.
- the display 14 displays the change information as image information or numerical information based on the display information generated by the display information generator 13.
- the specific configuration of the display 14 is not particularly limited, and a known liquid crystal display or the like can be suitably used.
- the porosity evaluation apparatus 10B may be configured by at least the ultrasonic detector 11 and the time-frequency analyzer 12 (in FIG. 5, for convenience of explanation)
- the probe 111 and the ultrasonic transmitter / receiver 112 are collectively shown as a block of the ultrasonic detector 11).
- the porosity evaluation apparatus 10B shown in FIG. 5 does not include the display 14 (and the display information generator 13). However, as shown in FIG. 5, an external display 23 can be connected. That's fine.
- the porosity evaluation apparatus 10A or 10B according to the present invention may include an analysis configuration other than the time-frequency analyzer 12. Specifically, for example, a known configuration for performing analysis, evaluation, inspection, or the like of the composite material 100 based on information related to other than the porosity evaluation obtained by receiving the reflected wave of the ultrasonic wave can be given.
- the porosity evaluation device 10A or 10B is configured to display the change information on the display device 14 or the display device 23. Therefore, the porosity evaluation in step S13 described above is evaluated based on image information or the like displayed by the operator of the porosity evaluation apparatus 10A or 10B (the person in charge of inspection of the composite material 100).
- the porosity evaluation device 10A or 10B itself may be configured to perform the porosity evaluation by providing a porosity evaluator as in the second embodiment described later.
- the porosity evaluation method and the porosity evaluation apparatus can satisfactorily evaluate the distribution state of the porosity in the thickness direction in the composite material.
- the porosity level can be evaluated well for different parts.
- the porosity evaluation method according to the present invention performs the porosity evaluation for each part, and also evaluates the strength reduction derived from the porosity, thereby enabling more efficient and good part evaluation.
- the porosity evaluation method (and porosity evaluation apparatuses 10A and 10B) according to the first embodiment is configured to evaluate the distribution in the thickness direction of the porosity 102 based on the reflected wave from the composite material 100.
- the porosity evaluation method according to the second embodiment is configured to more precisely estimate the distribution of the porosity 102 in the composite material 100 by further using numerical simulation.
- the porosity evaluation method according to the present embodiment will be specifically described with reference to FIG.
- steps S21 and S22 are the same as steps S11 and S12 in the porosity evaluation method according to the first embodiment, but steps S23 and S24 are performed. It contains different points.
- an ultrasonic wave is incident from the incident surface 103 toward the thickness direction of the composite material 100, and the total reflection of the ultrasonic wave from the incident surface 103 is performed.
- the wave Wr is received (step S21).
- time-frequency analysis of the received total reflected wave Wr is performed to obtain temporal change information of the interlayer reflected wave Wr2 included in the total reflected wave Wr (step S22).
- evaluation information for porosity evaluation is acquired (step S23). Then, the distribution of the porosity 102 in the composite material 100 is estimated by comparing the acquired change information with the evaluation information (step S24).
- the specific information for evaluation acquired in step S23 is not particularly limited, typically, (1) the defect composite material 100B or 100C including the modeled porosity 102, and the ultrasonic wave for the defect composite material 100B or 100C.
- Examples include known information of the interlayer reflected wave Wr2 obtained by preparing a test piece of the composite material 100 and performing incidence of an ultrasonic wave and reception of a reflected wave on the test piece.
- the former (1) is referred to as simulated change information
- the latter (2) is abbreviated as known information.
- the simulated reproduction of the defective composite material 100B or 100C is performed by modeling the porosity 102 as a rectangular cross section with side lengths distributed according to a Gaussian distribution, and simulated simulated composite material 100B. Alternatively, it is performed by randomly distributing in a cross section of 100C. Further, the simulated reproduction of the incidence of ultrasonic waves and the reception of reflected waves with respect to the defective composite material 100B or 100C is performed by using a finite element analysis method (FEM) using an actual ultrasonic wave incident waveform.
- FEM finite element analysis method
- the numerical simulation may be performed every time referring to the actual change information obtained in step S22 when the porosity evaluation of the composite material 100 is performed, or a database is obtained by performing a plurality of numerical simulations in advance. You may create it. Furthermore, after performing step S22, numerical simulation may be performed every time based on actual change information, and the obtained reproduction result may be registered in the database. That is, the numerical simulation result database may be gradually constructed in parallel with the implementation of the porosity evaluation. Even when the database is gradually constructed, a preliminary database may be created in advance by performing a numerical simulation under typical conditions before starting the porosity evaluation.
- a method for preparing a test piece for acquiring the known information is not particularly limited, so that the distribution state of the porosity 102 can be determined in advance.
- 100C may be manufactured by a known method.
- the estimation result (evaluation result) of the distribution of the porosity 102 obtained by the porosity evaluation method according to the present embodiment is accumulated and used as known information. Also good.
- the composite material 100 to be evaluated corresponds to a test piece for acquiring known information.
- the known information acquired from the test piece may be stored in a database and read out as appropriate, similarly to (1) simulated change information.
- the porosity evaluation method according to the present embodiment is not limited to the four steps shown in FIG.
- the process S23 for acquiring the evaluation information is performed after the process S22 for acquiring the actual change information.
- the process S23 is performed first
- the actual information is obtained.
- Change information may be acquired (steps S21 and S22 will be performed later). Further, steps other than steps S21 to S24 may be included.
- step S23 information stored in the database can be appropriately read and used regardless of whether the evaluation information is (1) simulated change information or (2) known information. Therefore, if the evaluation information is (1) simulated change information, the simulation result may be appropriately read from the database without performing numerical simulation after step S22. Moreover, the database does not need to be prepared in the field which implements a porosity evaluation method, and may be prepared in another place via a communication network. In this case, in step S23, the evaluation information is acquired by communication. Thus, the method for acquiring evaluation information in step S23 is not particularly limited.
- the evaluation information used in step S24 may be only one type or two or more types.
- the acquired actual change information may be compared with (1) simulated change information, or the actual change information may be compared with (2) known information. Both (1) simulated change information and (2) known information may be compared with the change information, and (1) simulated change information and (2) other information other than the known information are used as evaluation information. If one or more types can be used, these three or more types of information may be compared with actual change information.
- the porosity evaluation apparatus 10C or 10D according to the present embodiment basically has the same configuration as the porosity evaluation apparatus 10A or 10B according to the first embodiment. However, the point which is equipped with the porosity evaluation device 15 differs.
- the porosity evaluator 15 estimates the distribution of the porosity 102 in the composite material 100 by comparing the change information obtained from the time-frequency analyzer with the information for evaluation described above.
- the evaluation information (1) simulated change information, (2) known information, or both (or other information) can be used. These pieces of evaluation information can be obtained from the ultrasonic transmission / reception simulator 16 (simulated change information only) shown in FIG. 7 or the evaluation information database 17 (at least one of simulated change information and known information) shown in FIG. Good.
- the specific configuration of the porosity evaluator 15 is not particularly limited, and may be configured as a logic circuit using a known switching element, subtractor, comparator, or the like, or a functional configuration in which a known processor operates according to a program. May be. Further, the porosity evaluation performed by the porosity evaluator 15 is not limited to the evaluation in the above-described step S24, that is, the evaluation for estimating the distribution of the porosity 102 by comparing the actual change information and the information for evaluation. Other evaluation methods may be adopted.
- the porosity evaluator 15 is configured to acquire simulated change information from the ultrasonic transmission / reception simulator 16. Therefore, this porosity evaluation apparatus 10C corresponds to a configuration in which numerical simulation is performed every time in the above-described porosity evaluation method.
- the ultrasonic transmission / reception simulator 16 is configured to perform a numerical simulation for acquiring the above-described simulated change information.
- the specific configuration is not particularly limited as long as it is a functional configuration realized by a known processor operating in accordance with a numerical simulation program.
- the porosity evaluation apparatus 10D shown in FIG. 8 is configured such that the porosity evaluation unit 15 acquires at least one of simulated change information and known information from the evaluation information database 17. Therefore, this porosity evaluation apparatus 10D corresponds to a configuration that acquires a reproduction result from a database among the above-described porosity evaluation methods.
- the specific configuration of the evaluation information database 17 is not particularly limited as long as it is a known storage device that can store the database.
- the porosity evaluation apparatus 10C or 10D shown in FIG. 7 or FIG. 8 is configured to include only the ultrasonic transmission / reception simulator 16 or only the evaluation information database 17, but the present invention is not limited to this, and FIG. As shown in FIG. 6, the porosity evaluation apparatus 10E having both the ultrasonic transmission / reception simulator 26 and the evaluation information database 27 may be used.
- the porosity evaluation apparatus 10E shown in FIG. 9 is configured as a “porosity evaluation system” using a known ultrasonic flaw detector 21 and a known information processing apparatus 22.
- the known ultrasonic flaw detector 21 include an inspection device that inspects defects other than the porosity 102 or an inspection device that performs conventional porosity evaluation (total evaluation).
- the known information processing device 22 includes: For example, a personal computer or the like can be mentioned, but is not particularly limited. Therefore, the “porosity evaluation device” according to the present invention is not limited to a single “evaluation device” as shown in FIGS. 4, 5, 7 and 8, and a plurality of “devices” are connected to each other.
- the “evaluation system” is also included in the scope of the present invention.
- the information processing apparatus 22 itself may be configured to include the display 14.
- the ultrasonic transmission / reception simulator 26 and the evaluation information database 27 are not provided as internal configurations as in the porosity evaluation apparatus 10C or 10D shown in FIG. 7 or FIG.
- the “device” is connected to the information processing device 22. Therefore, also in the porosity evaluation apparatus 10C or 10D shown in FIG. 7 or FIG. 8, the ultrasonic transmission / reception simulator 16 or the evaluation information database 17 may be provided as an external configuration instead of an internal configuration.
- the result based on the actual measurement is compared with the simulated reproduction result (simulated change information) by the numerical simulation.
- the porosity level in the manufactured parts can be evaluated more finely. Therefore, it is possible to improve the evaluation accuracy of the parts, and it is possible to improve the accuracy of the evaluation of the strength reduction derived from the porosity.
- the porosity evaluation apparatuses 10C to 10E are each configured to include a porosity evaluation unit 15 that compares a result based on actual measurement with a simulated reproduction result based on numerical simulation.
- the present invention is not limited to this, and as described above, the distribution of the porosity 102 may be evaluated by other evaluation methods, and the operators of the porosity evaluation apparatuses 10C to 10E may be evaluated as in the first embodiment. Further evaluation may be performed based on the evaluation result of the porosity evaluator 15 (displayed as image information or the like on the display 14).
- the porosity evaluator 15 itself may be provided not only in one type but in two or more types.
- time-frequency analysis of reflected waves The time-frequency response was graphed and analyzed by performing a short-time Fourier transform (STFT) on the measurement time waveform of the ultrasonic reflected wave obtained from the porosity evaluation sample or the comparatively sound sample.
- STFT short-time Fourier transform
- the time range in which STFT is performed, and the type and width of the window function are appropriately set according to the frequency range and time range of interest.
- the time waveform was discretized for each sampling period and numerically processed.
- Laminated structure is a laminated structure in which the fiber directions of 24 plies are all in the same direction ([0] 24), and pseudo isotropic with fiber directions distributed evenly at angles of 0 °, 90 °, 45 °, -45 ° Two types of laminated structure ([45/0 / -45 / 90] 3s) were used.
- the carbon fiber used for UTS50 / 135 is a UD (Uni-Direction) material of UTS50 (trade name) manufactured by the company, and the matrix material used is a high-toughness epoxy resin manufactured by the company.
- the obtained porosity evaluation sample is a defective composite material in which half of one surface (front surface) side contains 4% porosity, and the other half (back surface) side does not contain porosity. It is a material (see FIG. 1A). Therefore, the total amount of porosity is 2% in the entire porosity evaluation sample.
- the reflected wave measured on the front or back surface was graphed by performing time-frequency analysis as described above. The result is shown in FIG. 11A (analysis result on the front surface side) and FIG. 11B (analysis result on the back surface side).
- the reflected waves on the front and back sides of the porosity evaluation sample were reproduced and graphed by the numerical simulation described above.
- the porosity was modeled as a rectangular cross section having an average value of 0.1 mm ⁇ 0.2 mm and a side length distributed according to a Gaussian distribution over the entire cross section of the porosity evaluation sample, and the surface side (see FIG. 1C). ).
- the results are shown in FIG. 12A (front side analysis result) and FIG. 12B (back side analysis result).
- the upper graph of FIG. 12A and FIG. 12B has shown the measurement result
- the lower graph has shown the result by numerical simulation.
- the reflected wave was measured by injecting ultrasonic waves from the front surface or the back surface in the same manner as in the example.
- the results of the porosity evaluation sample having the pseudo isotropic laminated structure are shown in “Comparative Example (front surface)” and “Comparative Example (back surface)” of FIG.
- the reflected wave measured on the front or back surface was graphed by performing time-frequency analysis as described above. The results are shown in FIG. 11C (front side analysis result) and FIG. 11D (back side analysis result).
- the inter-layer reflected wave Wr2 (solid line) following the surface reflected wave Wr0 (around 1.6 to 1.7 ⁇ s) in both the front and back total reflected waves Wr.
- a circled area (around 1.8 to 2.2 ⁇ s) is confirmed, but the vibration of the inter-layer reflected wave when incident from the surface disappears relatively early.
- the bottom reflected wave Wr1 (location surrounded by a broken-line circle, around 4.6 ⁇ s) is confirmed in both the front and back total reflected waves Wr. The bottom surface reflected wave Wr1 is not confirmed.
- the continuous vibration of the component near the frequency of 8 MHz following the surface reflected wave Wr0 is present in the region surrounded by the solid circle in the drawing. I can confirm. Even in the porosity evaluation sample, when an ultrasonic wave is incident from the back side, which is the healthy side, continuous vibration at a frequency of about 8 MHz can be confirmed in a region surrounded by a solid circle in FIG. 11B. On the other hand, when an ultrasonic wave is incident from the surface on which the porosity is unevenly distributed, as shown in FIG. 11A, the continuous vibration in the vicinity of the frequency of 8 MHz cannot be sufficiently confirmed.
- 11A to 11D are all results of the porosity evaluation sample having the pseudo isotropic laminated structure, but the results showing the same tendency are not shown for the porosity evaluation sample having the laminated structure in the same direction. Is obtained.
- the bottom surface reflected wave Wr1 cannot be confirmed regardless of whether the ultrasonic wave is incident from the front surface or the back surface, and a difference is observed in the component of the continuous vibration following the surface reflected wave. . Therefore, it is understood that the distribution in the thickness direction of the porosity included in the composite material can be evaluated by performing time-frequency analysis of the total reflected wave and acquiring temporal change information of the interlayer reflected wave.
- the numerical simulation result when the ultrasonic wave is incident from the front surface (defect uneven distribution side)
- the numerical simulation result when the ultrasonic wave is incident from the back surface (healthy side)
- the porosity Compared with the numerical simulation results when the wave is uniformly distributed, the continuous vibration following the surface reflected wave Wr0 is greater when the ultrasonic wave is incident from the healthy surface (back surface) than when the sound wave has a uniform porosity. It has been found that the continuous vibration that follows the surface reflected wave Wr0 attenuates more quickly when the ultrasonic wave is incident from the surface than when it has a uniform porosity.
- FIGS. 12A and 12B show the time-frequency analysis results when the reflected wave is actually measured in the porosity evaluation sample, and the lower graphs of FIGS. 12A and 12B are simulated by numerical simulation. Although the time-frequency analysis results are shown, it is clear from the comparison of the upper and lower graphs that the characteristics of the measured time-frequency analysis results of the reflected wave correspond well to the results of the numerical simulation.
- the change information of the simulated interlayer reflected wave obtained by numerical simulation (or the known information of the interlayer reflected wave obtained from the test piece whose porosity distribution is already known) is stored in the database in advance, it is measured. It can be seen that the distribution of the porosity in the composite material can be precisely estimated by comparing the change information from the interlayer reflected wave with the simulated change information (or a known porosity evaluation result).
- the present invention can be used widely and suitably in the field of evaluating the porosity contained in the fiber reinforced resin composite material.
- the present invention can be suitably used for porosity evaluation of composite materials used in the aerospace field where other structural strength requirements are severe.
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Abstract
Description
[複合材料]
まず、本発明においてポロシティの評価対象となる複合材料について図1A~図1Cを参照して具体的に説明する。なお、本発明においては、「ポロシティ」とは、前述したように、「分散した多数の微小な空孔状の欠陥」を意味する。「ポロシティ」という用語には、空孔状の欠陥の含有率を含む場合もあるが、本実施の形態では、「ポロシティ」は欠陥そのものを指すものとする。
次に、本実施の形態1に係るポロシティ評価方法について、図2および図3A~図3Cを参照して具体的に説明する。
それゆえ、入射周波数fは、超音波伝搬速度cおよびプライ101の厚さhを用いて下記(2)式として表現することができる。
プライ101がCFRP製であれば、超音波伝搬速度c(縦波伝搬速度)の代表的な値は約3,000m/sとなることが知られている。そこで、この超音波伝搬速度c=3,000m/sおよびプライ101の厚さhから、上記式(2)に基づいて入射周波数fを概算することができる。例えば、CFRP製のプライ101の厚さh=0.15mmであれば、その入射周波数f=10.0MHzに概算できる。また、プライ101の厚さh=0.19mmであれば、入射周波数f=7.9MHzに概算できる。また、プライ101の厚さh=0.40mmであれば、入射周波数3.8MHzに概算できる。
本実施の形態に係るポロシティ評価方法を実施する具体的な構成は特に限定されないが、当該ポロシティ評価方法を実施するための代表的なポロシティ評価装置(本実施の形態1に係るポロシティ評価装置)の一例について、図4および図5を参照して具体的に説明する。
前記実施の形態1に係るポロシティ評価方法(およびポロシティ評価装置10A、10B)は、複合材料100からの反射波に基づいて、ポロシティ102の厚さ方向の分布を評価する構成であったが、本実施の形態2に係るポロシティ評価方法は、さらに、数値シミュレーションを併用することにより、複合材料100内におけるポロシティ102の分布をより精細に推測する構成となっている。本実施の形態に係るポロシティ評価方法について、図6を参照して具体的に説明する。
図6に示すように、本実施の形態に係るポロシティ評価方法は、工程S21およびS22は前記実施の形態1に係るポロシティ評価方法における工程S11およびS12と同様であるが、工程S23および工程S24を含んでいる点が異なっている。
本実施の形態に係るポロシティ評価方法を実施する具体的な構成は特に限定されないが、前記実施の形態1と同様に、代表的なポロシティ評価装置(本実施の形態2に係るポロシティ評価装置)の一例について、図7、図8および図9を参照して具体的に説明する。
インサイト株式会社製FlexScan、および、公称中心周波数10MHzの水浸用探触子を用いて、ポロシティ評価用サンプルまたは比較健全サンプルの一方の面または他方の面に対して超音波パルスを入射し、反射波を受信した。
ポロシティ評価用サンプルまたは比較健全サンプルから得られた超音波の反射波の測定時間波形を、短時間フーリエ変換(STFT)することにより、時間-周波数応答をグラフ化して解析した。このとき、STFTを行う時間範囲、並びに、窓関数の種類およびその幅は、着目する周波数範囲および時間範囲に応じて適宜設定した。また、グラフ化に際しては、時間波形をサンプリング周期毎に離散化して数値処理した。
ISHII, Yosuke, and BIWA, Shiro, Journal of Applied Physics 111, No. 084907 (2012) に開示されている有限要素解析(FEM)に基づいて、陰解法を用いて、数値シミュレーションを行うことにより、ポロシティ評価用サンプルまたは比較健全サンプルにおける超音波の反射波を解析した。なお、数値シミュレーションにおいては、前記反射波の測定に用いた入射波形を模擬して用いた。この入射波形は、中心周波数7MHz程度の広帯域波となる。
東邦テナックス株式会社製の航空機用複合材料UTS50/135(商品名)を用いて、真空度750mmHg、加圧無し、硬化温度180℃の成形条件(オートクレーブ条件)で成形を行うことにより、120mm×100mmかつ積層数(プライ数)24(全体の厚さが約4.6mm)の寸法のポロシティ評価用サンプルを作製した。積層構成は、24プライの繊維方向が全て同一方向の積層構成([0]24)、および、繊維方向が0°、90°、45°、-45°の角度に均等に分配した擬似等方積層構成([45/0/-45/90]3s)の2種類とした。なお、UTS50/135に用いられる炭素繊維は、同社製UTS50(商品名)のUD(Uni-Direction)材であり、用いられるマトリクス材料は、同社製の高靭性エポキシ樹脂である。
ポロシティを含まないこと、並びに、成形条件の加圧を400kPaとしたこと以外は、実施例と同様にして、120mm×100mmかつ積層数(プライ数)24(全体の厚さが約4.6mm)の寸法の比較健全サンプルを作製した。
図10に示すように、ポロシティ評価用サンプルにおいては、表面および裏面のいずれの全体反射波Wrにおいても、表面反射波Wr0(1.6~1.7μs付近)に続く層間反射波Wr2(実線の円で囲んだ箇所、1.8~2.2μs付近)が確認されるが、表面から入射した場合の層間反射波の振動は比較的早期に消失している。また、比較健全サンプルにおいては、表面および裏面のいずれの全体反射波Wrにおいても底面反射波Wr1(破線の円で囲んだ箇所、4.6μs付近)が確認されるが、ポロシティ評価用サンプルにおいては、底面反射波Wr1は確認されない。
10B ポロシティ評価装置
10C ポロシティ評価装置
10D ポロシティ評価装置
11 超音波検出器
12 時間-周波数解析器
13 表示用情報生成器
14 表示器
15 ポロシティ評価器
16 超音波送受信シミュレータ
17 評価用情報データベース
21 超音波探傷装置
22 情報処理装置
23 表示装置
100 複合材料
100A 健全複合材料
100B 欠陥複合材料
100C 欠陥複合材料
101 プライ
102 ポロシティ
103 入射面
104 底面
105 層間界面
111 探触子
112 超音波送受信器
Wi 入射波
Wr 全体反射波
Wr0 表面反射波
Wr1 底面反射波
Wr2 層間反射波
Claims (8)
- プリプレグを複数枚積層した後に硬化させて得られる、多層構造の複合材料の一方の面を入射面として、当該入射面から前記複合材料の厚さ方向に向かって超音波を入射するとともに、当該入射面側において反射波を受信し、
受信した前記反射波を全体反射波とし、当該全体反射波に含まれる、前記多層構造の層間界面からの反射波を層間反射波としたときに、
前記全体反射波を時間-周波数解析することにより、前記複合材料に含まれるポロシティの厚さ方向の分布を評価するために用いられる、前記層間反射波の時間的な変化情報を取得する、
複合材料内のポロシティ評価方法。 - 前記複合材料の他方の面である底面から反射される底面反射波の減衰に基づいて、当該複合材料に含まれる前記ポロシティを総量的に評価するために用いられる超音波の入射周波数を、標準周波数としたときに、
前記超音波の入射周波数は、前記標準周波数よりも、高く設定される、
請求項1に記載の複合材料内のポロシティ評価方法。 - 前記入射周波数は、前記複合材料を構成するプライの厚さに応じて変更可能となっている、
請求項1または2に記載の複合材料内のポロシティ評価方法。 - 前記複合材料内における前記ポロシティの分布を推測するために、評価用情報と、実際に受信した前記層間反射波からの前記変化情報と、を対比し、
前記評価用情報としては、
モデル化した前記ポロシティを含む前記複合材料と、当該複合材料に対する前記超音波の入射および前記反射波の受信と、を模擬的に再現する数値シミュレーションを行うことにより得られる模擬的な前記層間反射波の変化情報、および、
既知の前記ポロシティを含む前記複合材料の試験片に対して、前記超音波の入射および前記反射波の受信を行うことにより取得される、前記層間反射波の既知情報、の少なくとも一方が用いられる、
請求項1から3のいずれか1項に記載の複合材料内のポロシティ評価方法。 - プリプレグを複数枚積層した後に硬化させて得られる、多層構造の複合材料の一方の面である入射面に対して、当該複合材料の厚さ方向に向かって超音波を入射するとともに、当該入射面からの反射波を受信する、超音波検出器と、
受信した前記反射波を全体反射波とし、当該全体反射波に含まれる、前記多層構造の層間界面からの反射波を層間反射波としたときに、
前記全体反射波を時間-周波数解析することで、前記複合材料に含まれるポロシティの厚さ方向の分布を評価するために用いられる、前記層間反射波の時間的な変化情報を取得する、時間-周波数解析器と、を備えている、
複合材料内のポロシティ評価装置。 - 前記変化情報から表示用情報を生成する表示用情報生成器と、
前記表示用情報を用いて前記変化情報を表示可能とする表示器と、をさらに備えている、
請求項5に記載の複合材料内のポロシティ評価装置。 - 前記時間-周波数解析器より得られる前記変化情報を、評価用情報と対比することにより、前記複合材料内における前記ポロシティの分布を推測する、ポロシティ評価器、を備え、
前記評価用情報として、模擬的な前記層間反射波の変化情報、および、予め取得した前記複合材料の前記層間反射波の既知情報の少なくとも一方が用いられ、
模擬的な前記層間反射波の前記変化情報は、モデル化した前記ポロシティを含む前記複合材料に対する、前記超音波の入射および前記反射波の受信を、数値シミュレーションにより模擬的に再現して得られるものであり、
前記既知情報は、既知の前記ポロシティを含む前記複合材料の試験片に対して、前記超音波の入射および前記反射波の受信を行うことにより取得されたものである、
請求項5または6に記載の複合材料内のポロシティ評価装置。 - 前記数値シミュレーションを行う超音波送受信シミュレータ、および、前記評価用情報を複数記憶する評価用情報データベースの少なくとも一方を備え、
前記ポロシティ評価器は、前記超音波送受信シミュレータ、および、前記評価用情報データベースの少なくとも一方から、前記評価用情報を取得する、
請求項7に記載の複合材料内のポロシティ評価装置。
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CN105158335B (zh) * | 2015-08-21 | 2018-03-23 | 南昌航空大学 | 一种钢‑玻璃钢复合板材脱粘超声导波评价方法 |
KR101904320B1 (ko) * | 2017-04-17 | 2018-10-04 | 연세대학교 산학협력단 | 전기적 신호를 이용한 구조물 보강재 진단 방법 및 장치 |
US10571385B2 (en) * | 2017-11-22 | 2020-02-25 | The Boeing Company | Ultrasonic inspection of a structure with a ramp |
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