JP7486745B2 - HARDENED BODY ANALYSIS METHOD, HARDENED BODY ANALYSIS SYSTEM, HARDENED BODY ANALYSIS DEVICE, AND HARDENED BODY ANALYSIS PROGRAM - Google Patents

Description

The present invention relates to a hardened body analysis method, a hardened body analysis system, a hardened body analysis device, and a hardened body analysis program.

Traditionally, when constructing hardened materials such as concrete or mortar, appropriate work is carried out depending on the hardened state of the hardened material. Therefore, when carrying out work, the hardened state of the hardened material is generally measured by a penetration test.

For example, the following Patent Document 1 discloses technology related to a testing machine for measuring the penetration resistance of hardened bodies in a penetration test. The tester holds the handle of the testing machine, places the penetration needle vertically against the surface of the cast hardened body, and pushes the handle vertically downward to cause the penetration needle to penetrate a specified distance into the hardened body. This allows the penetration resistance to be calculated based on the load the penetration needle receives when it penetrates.

JP 2014-102204 A

However, with the technology of Patent Document 1, if the test position is located in a position where the tester cannot insert the penetration needle into the hardened body from outside the application area of the hardened body (for example, near the center of the application area), the tester must step into the application area to insert the penetration needle into the test position. In this case, there is a risk that the tester will disturb the hardened body surface that has already been smoothed by stepping into the application area.

In view of the above-mentioned problems, the object of the present invention is to provide a method, a system, an apparatus, and a program for analyzing hardened bodies that can obtain information that allows understanding of the hardening state of a hardened body without disturbing the surface of the hardened body.

In order to solve the above-mentioned problems, a method for analyzing a hardened body according to one aspect of the present invention includes a laser irradiation step of irradiating a member partly inserted into a hardened body containing cement with a laser pulse light, a frequency response acquisition step of acquiring a frequency response of vibration in the member when the member is impulsively excited by the irradiation of the laser pulse light, and an analysis step of acquiring information indicating the hardened state of the hardened body based on the frequency response by an analysis unit.

The hardened body analysis system according to one aspect of the present invention includes a pulsed laser that irradiates a member that is partially inserted into a hardened body containing cement with a pulsed laser light, a vibration measuring instrument that obtains a frequency response of the vibration in the member when the member is impulsively excited by the irradiation of the pulsed laser light, and an analysis unit that obtains information indicating the hardened state of the hardened body based on the frequency response obtained by the vibration measuring instrument.

The hardened body analysis device according to one aspect of the present invention includes an analysis unit that acquires information indicating the hardened state of a hardened body based on the frequency response of vibrations in a member that is partially inserted into a cement-containing hardened body when the member is subjected to impulse vibrations by irradiation with a laser pulse light.

A hardened body analysis program according to one embodiment of the present invention causes a computer to function as an analysis unit that acquires information indicating the hardened state of a hardened body based on the frequency response of vibrations in a member that is partially inserted into a hardened body containing cement when the member is subjected to impulse vibrations by irradiation with laser pulse light.

According to the present invention, it is possible to obtain information that allows one to grasp the curing state of a cured body without disturbing the surface of the cured body.

FIG. 1 is a diagram illustrating a configuration of a hardened body analysis system according to an embodiment. 1 is a block diagram showing a functional configuration of a cured body analyzing apparatus according to an embodiment. FIG. 1 is a flowchart showing a flow of a hardened body analysis according to an embodiment. FIG. 2 is a diagram showing the results of a penetration resistance test according to Example 1. FIG. 11 is a perspective view of a structure according to a second embodiment. FIG. 11 is a diagram showing a configuration of a hardened body analysis system according to a second embodiment. FIG. 11 is a diagram showing an acquisition result of a power spectrum according to the second embodiment. FIG. 11 is a diagram showing an acquisition result of a primary resonance frequency according to the second embodiment. FIG. 11 is a diagram showing a calculation result of a primary resonance frequency according to the third embodiment. FIG. 13 is a diagram showing the calculation results of the change in elastic modulus over time according to Example 3.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In the drawings, mutually orthogonal X-axis, Y-axis, and Z-axis are shown as necessary. On each axis, the direction in which the arrow extends is referred to as the "positive direction," and the direction opposite to the positive direction is referred to as the "negative direction."

1. Configuration of hardened body analysis system
Fig. 1 is a diagram showing the configuration of a hardened body analysis system 1 according to one embodiment of the present invention. The hardened body analysis system 1 shown in Fig. 1 is a system that acquires a frequency response of vibration in a plate-like member 12 (one example of a member) inserted into a hardened body 10, and acquires information indicating the hardened state of the hardened body 10 (hereinafter, also referred to as "hardened state information") based on the frequency response.
The hardened body 10 of the present embodiment is, for example, a cement hardened body using cement. Specifically, the cement hardened body is mortar, concrete, etc. Mortar is a mixture of cement, sand, and water. Concrete is a mixture of cement, sand, gravel, and water. Note that the hardened body 10 is not limited to these examples.
The plate-shaped member 12 in this embodiment is, for example, a plate-shaped metal (metal plate). In this embodiment, an aluminum metal plate (aluminum beam) is used as the plate-shaped member 12. When the plate-shaped member 12 is an aluminum beam, its dimensions are, for example, 2 mm long (Y-axis direction) x 20 mm wide (X-axis direction) x 200 mm high (Z-axis direction). The shape, dimensions, and type of metal of the plate-shaped member 12 are not limited to the above example. The type of metal is not particularly limited as long as it is a common metal such as copper or iron. In addition, the material of the plate-shaped member 12 is not limited to metal. As shown in FIG. 1, a part of the plate-shaped member 12 is inserted into the hardened body 10. Hereinafter, the state in which a part of the plate-shaped member 12 is inserted into the hardened body 10 is also referred to as a "structure".

The hardened body analysis system 1 includes a pulsed laser 20, a focusing element 22, a vibration measuring meter 30, and a hardened body analyzing device 40. The vibration measuring meter 30 and the hardened body analyzing device 40 are communicatively connected to each other by wired communication or wireless communication. The pulsed laser 20, the focusing element 22, the vibration measuring meter 30, and the hardened body analyzing device 40 are provided outside the area where the hardened body 10 is processed (hereinafter also referred to as the "processing area"), in a state of not contacting the hardened body 10.
The pulsed laser 20 emits a laser pulse light 201 to be irradiated onto the plate-like member 12. In this embodiment, the laser pulse light 201 is a short pulse. The conditions of the laser pulse light 201, such as the wavelength spectrum width, time width, and pulse energy, are appropriately set so as to exceed the threshold value at which laser-induced plasma is generated on the surface of the irradiated plate-like member 12 by the irradiation of the laser pulse light 201 onto the plate-like member 12, and are set and adjusted by the parameters of the pulsed laser 20. Examples of the pulsed laser 20 having the above parameters include a Q-switched YAG laser and a Ti-sapphire laser. In this embodiment, the pulsed laser 20 irradiates the plate-like member 12, a part of which is inserted into the hardened body 10, with the laser pulse light 201. When a high-power laser such as the laser pulse light 201 is focused and irradiated onto a solid, the surface temperature of the solid rises rapidly, and a phenomenon occurs in which atoms, molecules, ions, and the like are explosively released. This phenomenon is called laser ablation (LA). In this embodiment, the laser pulse light 201 emitted from the pulse laser 20 is collected by the collecting element 22 and irradiated onto the plate-like member 12. As a result, laser ablation occurs at the irradiation position of the laser pulse light 201 on the plate-like member 12, and the emission material 14, such as atoms, molecules, and ions of the plate-like member 12, is emitted from the plate-like member 12. If the mass of the emission material 14 is m and the emission speed is v, the momentum of the emission material 14 is mv. The change in the momentum mv is an impulse, and an excitation force acts in the normal direction of the plate-like member 12. The excitation by laser ablation is an ideal impulse excitation. The frequency characteristics of the plate-like member 12 are reflected in the power spectrum measured by the impulse excitation by the emission material 14 emitted from the plate-like member 12.
The focusing element 22 focuses the laser pulse light 201 emitted from the pulsed laser 20 on the plate-like member 12. The focusing element 22 is, for example, a biconvex lens, but is not particularly limited as long as it has a focusing function. If the focusing element 22 is a biconvex lens, the conditions such as the numerical aperture, focal length, and refractive index of the focusing element 22 are appropriately set so that laser-induced plasma is generated by irradiating the plate-like member 12 with the laser pulse light 201. The focusing position of the laser pulse light 201 is a portion of the plate-like member 12 protruding from the hardened body 10.
The vibration measuring meter 30 acquires a frequency response of the vibration in the plate-like member 12 when the plate-like member 12 is impulse-vibrated by the laser pulse light 201. The vibration measuring meter 30 is, for example, a laser Doppler vibrometer. Note that the vibration measuring meter 30 is not limited to the laser Doppler vibrometer as long as it is a device capable of acquiring a frequency response.

In this embodiment, the frequency response is considered to be equivalent to a power spectrum when the plate-like member 12 is impulsively vibrated by laser ablation. Therefore, the vibration measuring meter 30 measures the time history response when the plate-like member 12 is vibrated by laser ablation, and obtains the power spectrum obtained by Fourier transforming the time history response as the frequency response.
If the time history response of the input is f(t) and the time history response of the output is x(t), the respective Fourier transforms F(ω) and X(ω) are expressed as the following equations (1) and (2).

On the other hand, the output time history response x(t) can be calculated by the convolution integral of the impulse response function h(t) and the input time history response f(t), as shown in the following equation (3).

The Fourier transform of equation (3) is expressed as the following equation (4) due to the properties of the convolution integral.

Here, H(ω) is the frequency response function of the system. When the input is considered as an impulse response, in an ideal state, f(t) can be considered to be a Dirac delta function. In this case, the Fourier transform of f(t) is F(ω) = 1. Therefore, equation (4) can be expressed as the following equation (5).

According to the formula (5), the Fourier transform of the time history response x(t) of the output is a frequency response function. As described above, in this embodiment, the frequency response and the power spectrum obtained by the impulse excitation by the laser ablation can be regarded as equivalent.
In this embodiment, the vibration measuring meter 30 acquires a power spectrum of the vibration of the plate-like member 12 when the plate-like member 12 is impulse-vibrated by irradiation of the laser pulse light 201 at a predetermined measurement frequency (e.g., 0 Hz to 2000 Hz) and sampling points (e.g., 4096 points). The vibration measuring meter 30 transmits the acquired power spectrum as a frequency response to the hardened body analyzing device 40. The hardened body analyzing device 40 acquires hardening state information of the hardened body 10 based on the frequency response acquired by the vibration measuring meter 30. For example, the hardened body analyzing device 40 acquires the elastic coefficient (Young's modulus) of the hardened body 10 as the hardening state information. The elastic coefficient is a physical property value that indicates how difficult an object is to deform. The smaller the value of the elastic coefficient, the easier the object is to deform, and the larger the value, the more difficult the object is to deform. Therefore, the user can grasp the hardening state of the hardened body 10 based on the elastic coefficient of the hardened body 10 acquired by the hardened body analyzing device 40. In addition, the user can grasp the progress of hardening of the hardened body 10 by looking at the time series change in the elastic modulus of the hardened body 10.

As described above, in the hardened body analysis system 1 of this embodiment, the pulsed laser 20 irradiates the plate-shaped member 12 with a laser pulse light 201, and the vibration measuring instrument 30 acquires the frequency response of the vibration in the plate-shaped member 12. The pulsed laser 20 can irradiate the plate-shaped member 12 with the laser pulse light 201 from a remote location (e.g., outside the construction area of the hardened body 10) without contacting the structure. The vibration measuring instrument 30 can acquire the frequency response of the plate-shaped member 12 from a remote location without contacting the structure. The hardened body analysis device 40 then acquires hardened state information based on the frequency response acquired by the vibration measuring instrument 30. This allows the user to acquire hardened state information of the hardened body 10 without stepping into the construction area. In other words, the user can acquire hardened state information of the hardened body 10 without disturbing the surface of the hardened body.

2. Functional configuration of the hardened body analysis device
Next, the functional configuration of the hardened body analyzing device 40 according to one embodiment of the present invention will be described with reference to Fig. 2. Fig. 2 is a block diagram showing the functional configuration of the hardened body analyzing device 40 according to one embodiment of the present invention. As shown in Fig. 2, the hardened body analyzing device 40 includes a communication unit 41, a control unit 42, a storage unit 43, an input unit 44, and an output unit 45.

The communication unit 41 has a function of transmitting and receiving various information. For example, the communication unit 41 receives a frequency response from the vibration measuring meter 30 and outputs it to the control unit 42.

The control unit 42 has a function of controlling the overall operation of the hardened body analyzing device 40. The control unit 42 is realized, for example, by causing a central processing unit (CPU) provided as hardware in the hardened body analyzing device 40 to execute a program.
As shown in FIG. 2 , the control unit 42 includes an analysis unit 420 .

The analysis unit 420 acquires the cured state information of the hardened body 10 based on the frequency response of the plate-like member 12 acquired by the vibration measuring meter 30. In this embodiment, the analysis unit 420 acquires the elastic coefficient (Young's modulus) of the hardened body 10 as the cured state information. For example, when the frequency response is the power spectrum of the plate-like member 12, the analysis unit 420 calculates the elastic coefficient of the hardened body 10 based on the primary resonance frequency indicated by the power spectrum. The primary resonance frequency indicated by the power spectrum is, for example, the frequency at the position showing the largest peak in the power spectrum. As an example, the analysis unit 420 calculates the elastic coefficient of the hardened body 10 by FEM (Finite Element Method) analysis. The analysis unit 420 can calculate the elastic coefficient of the hardened body 10 when the primary resonance frequency occurs in the vibration of the plate-like member 12 due to the irradiation of the laser pulse light 201 by the pulse laser 20 by the FEM analysis.
The analysis unit 420 performs FEM analysis on the model from which the elastic coefficient is to be acquired, based on the setting information and the acquired primary resonance frequency, and calculates the elastic coefficient of the hardened body 10. In this embodiment, a model of a structure in which a part of the plate-like member 12 is inserted into the hardened body 10 from which the elastic coefficient is to be acquired is prepared in advance. The setting information is, for example, the physical property values of the model of the structure. In this embodiment, the physical property values of the hardened body 10 and the physical property values of the plate-like member 12 that constitute the structure are set. The physical property values of the hardened body 10 include the density, elastic coefficient (variable), Poisson's ratio, and damping coefficient of the hardened body 10. The physical property values of the plate-like member 12 include the density, elastic coefficient, Poisson's ratio, and damping coefficient.
The elastic coefficient obtained by the FEM analysis is an average value of the portion of the plate-like member 12 inserted into the hardened body 10. Therefore, the elastic coefficient obtained by the FEM analysis is affected by the length of the portion of the plate-like member 12 inserted into the hardened body 10. Therefore, by adjusting the length of the portion of the plate-like member 12 inserted into the hardened body 10, it is possible to grasp the hardened state not only near the surface of the hardened body 10 but also inside. For example, the longer the length of the portion of the plate-like member 12 inserted into the hardened body 10, the more the elastic coefficient is calculated taking into account the hardened state of the inside. On the other hand, the shorter the length of the portion of the plate-like member 12 inserted into the hardened body 10, the more the elastic coefficient is calculated taking into account the hardened state of the portion closer to the surface.
The analysis unit 420 outputs the acquired cured state information of the cured body 10. For example, the analysis unit 420 converts the cured state information into information that can be output by the output unit 45, and outputs it to the output unit 45. Specifically, the analysis unit 420 may output the cured state information to the output unit 45 as a numerical value, or may output to the output unit 45 a graph showing the time series change of the cured state information.

The storage unit 43 has a function of storing various types of information.
The memory unit 43 is composed of a storage medium that the hardened body analysis device 40 has as hardware, such as a HDD (Hard Disk Drive), flash memory, EEPROM (Electrically Erasable Programmable Read Only Memory), RAM (Random Access read/write Memory), ROM (Read Only Memory), or any combination of these storage media.

The input unit 44 has a function of accepting input from a user. The input unit 44 outputs the accepted input to the control unit 42. The input unit 44 can be realized by, for example, an input device such as a touch panel, a keyboard, or a mouse that the hardened body analysis device 40 has as hardware.

The output unit 45 has a function of outputting various information, for example, the output unit 45 outputs the curing state information input from the control unit 42.
The function of the output unit 45 is realized, for example, by a display device such as a display included as hardware in the hardened body analyzing device 40. When the function of the output unit 45 is realized by a display device, the output unit 45 displays the hardened state information input from the control unit 42 on the display device.

<3. Hardened body analysis flow>
3 is a flowchart showing a flow of a cured body analysis according to an embodiment of the present invention. The flow of the cured body analysis according to this embodiment includes a laser irradiation step, a frequency response acquisition step, and an analysis step.

First, the pulsed laser 20 performs a laser irradiation step (S100) for irradiating a target with a pulsed laser beam 201. For example, the pulsed laser 20 irradiates the pulsed laser beam 201 to a plate-like member 12, a part of which is inserted into a hardened body 10 using cement.
Next, the vibration measuring meter 30 performs a frequency response acquisition step for acquiring a frequency response (S102). For example, the vibration measuring meter 30 acquires a frequency response related to the vibration of the plate-like member 12 excited by irradiation with the pulsed laser light 201. Specifically, the vibration measuring meter 30 acquires, as the frequency response, a power spectrum when the plate-like member 12 is impulse-excited by irradiation with the pulsed laser light 201.
Next, the analysis unit 420 performs an analysis step for acquiring the cured state information (S104 and S106). In the analysis step, the analysis unit 420 acquires the cured state information of the hardened body 10 based on the power spectrum (frequency response) of the vibration in the plate-like member 12 acquired by the vibration measuring meter 30. The analysis step includes a primary resonance frequency acquisition step and an FEM analysis step.
First, the analysis unit 420 performs a primary resonance frequency acquisition step for acquiring a primary resonance frequency (S104). Specifically, the analysis unit 420 acquires, as the primary resonance frequency, a frequency value of a point considered to be a primary resonance peak from the power spectrum of the vibration of the plate-like member 12 acquired by the vibration measuring meter 30.
Next, the analysis unit 420 performs an FEM analysis step to acquire the elastic modulus (S106). The analysis unit 420 calculates the elastic modulus of the hardened body 10 based on the primary resonance frequency indicated by the power spectrum. Specifically, the analysis unit 420 calculates the elastic modulus of the hardened body 10 by FEM analysis based on the primary resonance frequency acquired in the primary resonance frequency acquisition step.

As described above, in the hardened body analysis method according to the present embodiment, in the laser irradiation process, the plate-shaped member 12, a part of which is inserted into the hardened body 10 using cement, is irradiated with laser pulse light 201. In addition, in the frequency response acquisition process, the frequency response of the vibration in the plate-shaped member 12 impulse-excited by the irradiation of the laser pulse light 201 is acquired. In addition, in the analysis process, the analysis unit 420 acquires hardened state information of the hardened body 10 based on the frequency response. With this method, the worker checking the hardened state of the hardened body 10 can acquire hardened state information at the confirmation position of the hardened state without stepping into the construction area, and can grasp the hardened state at the confirmation position. Therefore, according to the hardened body analysis method according to the present embodiment, it is possible to acquire information that allows the hardened state of the hardened body to be grasped without disturbing the surface of the hardened body.

The above describes an embodiment of the present invention. The hardened body analysis device 40 in the above embodiment may be realized in whole or in part by a computer. In that case, a program for realizing this function may be recorded in a computer-readable recording medium, and the program recorded in the recording medium may be read into a computer system and executed to realize the function. The term "computer system" as used herein includes hardware such as an OS and peripheral devices. The term "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, and storage devices such as hard disks built into a computer system. The term "computer-readable recording medium" may also include a medium that dynamically holds a program for a short period of time, such as a communication line when a program is transmitted via a network such as the Internet or a communication line such as a telephone line, and a medium that holds a program for a certain period of time, such as a volatile memory inside a computer system that is a server or client in such a case. The above program may be a program for realizing a part of the above-mentioned function, or may be a program that can realize the above-mentioned function in combination with a program already recorded in the computer system, or may be a program that is realized using a programmable logic device such as an FPGA (Field Programmable Gate Array).

Although the embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to the above, and various design changes, etc. are possible within the scope that does not deviate from the gist of the present invention.
In the above embodiment, an example has been described in which the hardened state information is the elastic modulus of the hardened body 10, but the hardened state information is not limited to such an example. For example, the hardened state information may be a time history response of the vibration of the plate-like member 12 or a power spectrum.
In the above embodiment, an example has been described in which the vibration measuring meter 30 has a function of acquiring a frequency response, but the present invention is not limited to such an example. For example, the hardened body analyzing device 40 may have a function of acquiring a frequency response. In this case, for example, the hardened body analyzing device 40 has an acquiring unit (not shown), which acquires measurement data from the vibration measuring meter 30 and acquires a frequency response based on the measurement data.
The cured body analyzing device 40 may further include an operation control unit (not shown) for controlling the operations of the pulsed laser 20 and the vibration measuring meter 30. The operation control unit controls, for example, the irradiation (e.g., the irradiation timing, etc.) of the laser pulse light 201 onto the plate-like member 12 by the pulsed laser 20. The operation control unit also controls, for example, the acquisition process (e.g., the acquisition timing, etc.) of the frequency response of the vibration in the plate-like member 12 by the vibration measuring meter 30.

<4. Example 1>
In Example 1, a penetration resistance test was performed on the hardened body 10. The test results are used as true values of the hardened state of the hardened body 10 in verifying the FEM analysis results in Example 3 described later.

In the penetration resistance test, the load applied to the rod when a rod of a specified standard is pushed into mortar placed in a formwork of a specified standard is measured. Specifically, after water is poured into the mortar, the rod is pushed in at each predetermined time, and the load is measured. The penetration resistance value is calculated by dividing the measured load by the cross-sectional area of the rod. In Example 1, the temperature of the mortar was changed and five experiments were performed. Specifically, the temperature of the mortar was changed to 13.8°C, 16.0°C, 18.7°C, 19.1°C, and 33.0°C, and the penetration resistance test was performed at each temperature. Note that each temperature indicates the average temperature from the preparation of the test specimen to the end of the test.
FIG. 4 is a diagram showing the results of the penetration resistance test according to Example 1. The horizontal axis of FIG. 4 indicates time (minutes), and the vertical axis indicates the penetration resistance value (N/mm ² ). From the results shown in FIG. 4, it can be seen that at any temperature, the penetration resistance value at the beginning of hardening is almost 0, and the penetration resistance value increases rapidly from a certain point. This indicates that the penetration resistance value increases as the mortar hardens with the passage of time. In addition, from the results shown in FIG. 4, it can be seen that the lower the mortar temperature, the slower the change in the mortar penetration resistance value over time, and the higher the mortar temperature, the faster the change in the mortar penetration resistance value over time. In other words, it can be said that the lower the mortar temperature, the slower the hardening speed, and the higher the mortar temperature, the faster the hardening speed. This is because the higher the temperature, the faster the chemical reaction between cement and water proceeds, and the lower the temperature, the slower the chemical reaction between cement and water proceeds.

From the above, it was confirmed from Example 1 that the change in the penetration resistance value associated with the hardening of the mortar is affected by the mortar temperature.

<5. Example 2>
By using the pulsed laser 20 and the vibration measuring meter 30, the primary resonance frequency of the vibration in the plate-like member can be obtained. If there is a relationship between the primary resonance frequency and the change in the cured state of the cured body, it may be possible to grasp the cured state of the cured body based on the primary resonance frequency. That is, it is possible to grasp the cured state of the cured body by the method using the pulsed laser 20 and the vibration measuring meter 30. Therefore, in Example 2, an experiment was conducted to verify whether there is a relationship between the primary resonance frequency of the vibration in the plate-like member and the cured state of the cured body when a plate-like member partly inserted in the cured body is irradiated with laser pulse light.

Fig. 5 is a perspective view of a structure 50 according to Example 2. In Example 2, the structure 50 shown in Fig. 5 was prepared, and various experiments were performed. The structure 50 has mortar 54 (an example of a hardened body 10) placed in a container 52, and a part of an aluminum beam 60 (an example of a plate-like member 12) inserted into the mortar 54. The mortar 54 was prepared using the same material and by the same method as the mortar used in Example 1.
FIG. 6 is a diagram showing the configuration of the hardened body analysis system 2 according to Example 2. In Example 2, in addition to the configuration of the hardened body analysis system 1 in the above-mentioned embodiment, a reflecting mirror 24-1 and a reflecting mirror 24-2 are further provided. The reflecting mirror 24-1 and the reflecting mirror 24-2 appropriately fold back the laser pulse light 201 emitted from the pulse laser 20. The reflecting mirror 24-1 and the reflecting mirror 24-2 are provided so that the laser pulse light 201 passes through the focusing element 22 and is focused at the irradiation position 16 of the aluminum beam 60. The vibration measuring meter 30 measures the power spectrum of the vibration at the measurement position 18 of the aluminum beam 60. First, the vibration measuring meter 30 acquires the time history response of the vibration in the aluminum beam 60 based on the measurement result. Next, the vibration measuring meter 30 acquires the power spectrum of the vibration in the aluminum beam 60 by Fourier transforming the acquired time history response. Then, the vibration measuring meter 30 outputs the acquired power spectrum to the hardened body analysis device 40. The hardened body analyzing device 40 obtains the primary resonance frequency of vibration in the aluminum beam 60 based on the power spectrum input from the vibration measuring meter 30 .
The time history response obtained by the vibration measuring meter 30 based on the measurement results will be described. The time history response is represented, for example, by a graph in which the horizontal axis indicates time (seconds) and the vertical axis indicates voltage (V). In Example 1, the graph of the time history response shows that the vibration of the aluminum beam 60 becomes less attenuated as time passes from the start of the experiment. That is, it was found that the attenuation of the vibration of the aluminum beam 60 becomes smaller as the mortar 54 hardens.
With reference to FIG. 7, the power spectrum of the vibration in the aluminum beam 60 acquired by the vibration measuring meter 30 based on the measurement results will be described. FIG. 7 is a diagram showing the acquisition result of the power spectrum in Example 2. The graph in FIG. 7 shows an enlarged graph of the vicinity of the first resonance peak in the power spectrum measured at each predetermined time lapse from the start of the experiment. The horizontal axis of the graph in FIG. 7 indicates frequency (Hz), and the vertical axis indicates magnitude (dB). Curves S1 to S8 indicate the power spectrum measured after 300 minutes, 330 minutes, 360 minutes, 390 minutes, 420 minutes, 480 minutes, 510 minutes, and 540 minutes, respectively. From FIG. 7, it can be seen that a roughly determined response appears in the frequency response of the vibration in the aluminum beam 60. For example, a large peak (first resonance peak) appears between 100 Hz and 150 Hz, and the peak moves toward the high frequency side as time passes. This is considered to be because the support of the aluminum beam 60 becomes stronger as the mortar 54 hardens.
With reference to FIG. 8, the primary resonance frequency of the vibration in the aluminum beam 60 acquired by the hardened body analysis device 40 based on the power spectrum will be described. FIG. 8 is a diagram showing the acquisition result of the primary resonance frequency in Example 2. The horizontal axis of the graph in FIG. 8 indicates time (minutes), and the vertical axis indicates the primary resonance frequency (Hz) of the vibration in the aluminum beam 60. The graph in FIG. 8 is a record of the frequency at the primary resonance peak shown by the power spectrum over time. FIG. 8 shows that the primary resonance frequency of the aluminum beam 60 changes from 80 Hz to about 140 Hz until about 600 minutes after the start of the experiment, and then converges to about 150 Hz. From this, it can be seen that the primary resonance frequency of the vibration in the aluminum beam 60 changes over time, that is, changes with the hardening of the mortar 54.

As described above, from Example 2, it was found that there is a correlation between the primary resonance frequency of the plate-shaped member obtained by the method using the pulsed laser 20 and the vibration measuring meter 30 and the change in the hardening state of the hardened body. This means that it is possible to grasp the hardening state of the hardened body based on the primary resonance frequency. In other words, it is possible to grasp the hardening state of the hardened body by the method using the pulsed laser 20 and the vibration measuring meter 30. The experiment of Example 2 was performed multiple times, and similar results were obtained in each case, so the reproducibility of the experiment was also confirmed.

<6. Example 3>
As shown in Example 1, the penetration resistance value of the hardened body can be obtained by the penetration resistance test. Also, as shown in Example 2, the primary resonance frequency of the plate-like member can be obtained by the method using the pulse laser 20 and the vibration measuring meter 30. Furthermore, the elastic modulus of the hardened body can be calculated by FEM analysis using the primary resonance frequency of the plate-like member obtained by this method. When the penetration resistance value obtained by the penetration resistance test and the elastic modulus obtained by the FEM analysis change with the hardening of the hardened body, if there is a relationship between the changes of the two, it can be said that it is possible to grasp the hardening state of the hardened body by the method using the pulse laser 20 and the vibration measuring meter 30 instead of the penetration resistance test.
Therefore, in Example 3, an experiment was conducted to verify whether there is a relationship between the change in the penetration resistance value obtained by the penetration resistance test and the change in the elastic modulus obtained by the FEM analysis as the hardened body hardens.

In Example 3, a model of the structure 50 (excluding the container 52) shown in FIG. 5 is created in advance. The dimensions of the mortar 54 of the model are 150 mm long (Y-axis direction) × 150 mm wide (X-axis direction) × 108 mm high (Z-axis direction). The four corners of the mortar 54 are provided with a fillet of 25 mm. The dimensions of the aluminum beam 60 of the model are 2 mm long (Y-axis direction) × 20 mm wide (X-axis direction) × 200 mm high (Z-axis direction). The length of the aluminum beam 60 inserted into the mortar 54 was set to 101 mm, and the length of the aluminum beam 60 protruding from the mortar 54 was set to 99 mm.
In the FEM analysis, the analysis conditions are set in advance. For example, the analysis conditions are the physical property values and boundary conditions of the model. In the third embodiment, the physical property values of the aluminum beam 60 model are set as follows: density: 2.85×10 ⁻⁶ (kg/mm ³ ), elastic modulus: 4.70×10 ⁴ (MPa), Poisson's ratio: 0.33, and damping coefficient: 0. The physical property values of the mortar 54 are set as follows: density: 1.49×10 ⁻⁶ (kg/mm ³ ), elastic modulus: variable, Poisson's ratio: 0.25, and damping coefficient: 0. The elastic modulus of the mortar 54 is set as variable in order to perform FEM analysis at each value while changing the setting by 1 MPa. As the boundary conditions, the bottom surface of the mortar 54 model is fixed in all directions, the normal direction of the side surface is fixed, and the contact portion between the mortar 54 model and the aluminum beam 60 model is set as bonding.
In the FEM analysis, a mesh is created for the model in which the above-mentioned physical property values and boundary conditions are set, and then the analysis is performed. In this embodiment, the number of nodes of the mesh is set to 116432, and the number of elements is set to 81709.
The hardened body analyzing device 40 performs FEM analysis on the model of the structure 50 based on the analysis conditions. First, the hardened body analyzing device 40 changes the elastic modulus of the mortar 54 by 1 MPa in the FEM analysis, and calculates the primary resonance frequency of the vibration of the aluminum beam 60 at each elastic modulus of the mortar 54. Next, the hardened body analyzing device 40 calculates the time change of the elastic modulus of the mortar 54 corresponding to the primary resonance frequency of the aluminum beam 60 based on the calculated primary resonance frequency of the aluminum beam 60 and the time change of the primary resonance frequency obtained in Example 2. Next, the hardened body analyzing device 40 compares the calculated time change of the elastic modulus of the mortar 54 with the time change of the penetration resistance value of the mortar of Example 1 (prepared under the same conditions as the mortar 54).
The calculation results of the primary resonance frequency of the aluminum beam 60 by FEM analysis will be described with reference to Fig. 9. Fig. 9 is a diagram showing the calculation results of the primary resonance frequency according to Example 3. The horizontal axis of the graph in Fig. 9 indicates the elastic modulus (MPa) of the mortar 54, and the vertical axis indicates the primary resonance frequency (Hz) of the aluminum beam 60. Fig. 9 shows that as the elastic modulus of the mortar 54 increases, the primary resonance frequency of the aluminum beam 60 increases, and when the elastic modulus reaches a certain level, the primary resonance frequency converges to a predetermined value.
The calculation results of the change in the elastic modulus of mortar 54 over time will be described with reference to Fig. 10. Fig. 10 is a diagram showing the calculation results of the change in the elastic modulus over time according to Example 3. The horizontal axis of the graph in Fig. 10 indicates time (minutes), and the vertical axis indicates the elastic modulus of mortar 54 (MPa).
10, it can be seen that as time passes from the start of the experiment, the elastic modulus of the mortar 54 increases. This shows that the elastic modulus of the mortar 54 changes with the passage of time, that is, changes with the hardening of the mortar 54.
Here, with reference to FIG. 4 and FIG. 10, a comparison result between the time change of the elastic modulus of mortar 54 and the time change of the penetration resistance value of the mortar of Example 1 (prepared under the same conditions as mortar 54) will be described. FIG. 4 shows that the penetration resistance value of the mortar obtained by the penetration resistance test of Example 1 increases with time. FIG. 10 shows that the elastic modulus of mortar 54 calculated by FEM analysis increases with time. From this, it can be seen that the time change of the elastic modulus of mortar 54 and the penetration resistance value of mortar are similar. Note that the graph showing the time change of the penetration resistance value of mortar shown in FIG. 10 is particularly similar to the graph showing the time change of the penetration resistance value obtained in Example 1 shown in FIG. 4 when the mortar temperature is 16.0 ° C.

As described above, from Example 3, it was found that the tendency of change in the penetration resistance value obtained by the penetration resistance test and the elastic modulus obtained by the FEM analysis is similar when they change with the hardening of the hardened body. This means that it is possible to grasp the hardening state of the hardened body based on the elastic modulus obtained by the FEM analysis instead of the penetration resistance value obtained by the penetration resistance test. The primary resonance frequency used in the FEM analysis is based on the frequency response obtained by the method using the pulse laser 20 and the vibration measuring meter 30. Therefore, it is possible to grasp the hardening state of the hardened body by the method using the pulse laser 20, the vibration measuring meter 30, and the FEM analysis instead of the penetration resistance test.

1...hardened body analysis system, 10...hardened body, 12...plate-like member, 14...emitted material, 16...irradiation position, 18...measurement position, 20...pulse laser, 22...light-collecting element, 24-1...reflector, 24-2...reflector, 30...vibration measuring device, 40...hardened body analysis device, 41...communication unit, 42...control unit, 43...storage unit, 44...input unit, 45...output unit, 50...structure, 52...container, 54...mortar, 60...aluminum beam, 201...laser pulse light, 420...analysis unit

Claims (6)

a laser irradiation step of irradiating a laser pulse light onto a member partly inserted into the hardened body using the cement;
a frequency response acquisition step of acquiring a frequency response of vibration in the member when the member is impulse-vibrated by irradiation with the laser pulse light;
an analysis step of acquiring information indicating a cured state of the cured body based on the frequency response by an analysis unit;
A method for analyzing a hardened body, comprising: The analysis unit calculates an elastic modulus of the hardened body as the information based on a primary resonance frequency indicated by the frequency response.
The method for analyzing a hardened body according to claim 1 . The analysis unit calculates an elastic modulus of the hardened body by a finite element method (FEM) analysis based on the primary resonance frequency.
The method for analyzing a hardened body according to claim 2 . A pulsed laser that irradiates a laser pulse light onto a member that is partly inserted into a hardened body containing cement;
a vibration measuring meter for acquiring a frequency response of vibration in the member when the member is impulsively excited by irradiation with the laser pulse light;
an analysis unit that acquires information indicating a cured state of the cured body based on the frequency response acquired by the vibration measuring meter;
A hardened body analysis system comprising: an analysis unit that acquires information indicating a hardened state of the hardened body based on a frequency response of vibration in a member when the member, a part of which is inserted into the hardened body using cement, is impulsively excited by irradiation of the laser pulse light;
A hardened body analysis device comprising: Computer,
an analysis unit that acquires information indicating a hardened state of the hardened body based on a frequency response of vibration in a member when the member, a part of which is inserted into the hardened body using cement, is impulsively excited by irradiation of the laser pulse light;
This hardening analysis program functions as a.

Images