Sealant deterioration detection method and detection system

Abstract

To provide a sealant deterioration detection method for detecting in a non contact state, deterioration of a sealant exposed from an outer wall.SOLUTION: A sealant deterioration detection method comprises: a step for radiating a wave B for multiple frequencies along a sealant 22, and receiving reflection waves C reflected on an outer wall 20, for every partitioned region of the sealant 22; a step for calculating an amplitude ratio of the reflection waves C and a phase difference of the reflection waves C; a step for using at least one of the amplitude ratio and the phase difference in each frequency for each partitioned region for setting at least two or more kinds of clusters to each partitioned section A, then performing cluster analysis of classifying each partitioned section A into any of the set clusters; a step for determining that the sealant 22 is partially deteriorated when multiple partitioned sections A positioned on the sealant 22 are classified into any of the two or more kinds of clusters, and the partitioned sections in the same kind of clusters exist continuously by a prescribed number or more, on the basis of the classification result.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a detection method and a detection system for detecting deterioration of a sealant disposed between siding boards that constitute the exterior wall of a building. [Background technology]

[0002] Traditionally, sealants have been placed between the siding boards that make up the exterior walls of buildings to prevent rainwater and other elements from penetrating inside the walls. The sealants harden when exposed to heat or ultraviolet light, and their ability to conform to the deformation and contraction / expansion of the exterior wall material decreases, leading to a deterioration process that can lead to cracks and breaks. As deterioration progresses, rainwater can seep into the wall, causing leaks and expanding the area of ​​deterioration, so it is common to detect deterioration early and perform maintenance (replacement).

[0003] Normally, deterioration of sealants can be diagnosed by visually checking for cracks or breaks, but at this stage the sealant has already reached the end of its life and the damage may have spread due to rainwater seepage, so this is not an effective way to detect the deterioration at an early stage.

[0004] On the other hand, when considering the deterioration process, it is possible to investigate the degree of deterioration from the hardness of the sealant, and a method has been proposed in which a durometer (rubber hardness tester) is used to determine the degree of deterioration by the depth to which a needle is pressed into the sealant.

[0005] For example, Patent Document 1 discloses a method for detecting deterioration of a sealant by inserting a measuring needle into the sealant and determining the deterioration of the sealant from the load acting on the measuring needle. In addition, Patent Document 2 discloses a technology for diagnosing deterioration inside an exterior wall material using electromagnetic waves. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2020-129004 A [Patent Document 2] JP 2020-183919 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the technology shown in Patent Document 1, deterioration is judged by contacting a measuring needle with the sealant, so there is a risk of damaging the sealant being measured. For this reason, even if the technology shown in Patent Document 2 is used, deterioration such as corrosion of the wood inside the exterior wall can be detected by detecting moisture in the exterior wall material from reflected electromagnetic waves, but deterioration of the sealant cannot be detected. Sealant may deteriorate partially due to the effects of sunlight, etc., but it is difficult to detect such partial deterioration without contact.

[0008] The present invention has been made in consideration of such problems, and its object is to provide a sealant deterioration detection method and detection system that can detect deterioration of a sealant exposed from an exterior wall in a non-contact manner. [Means for solving the problem]

[0009] After extensive research, the inventors discovered that when a sealant deteriorates, its hardness changes, and that this change in hardness can be identified by the reflected waves of electromagnetic waves irradiated onto the sealant.

[0010] The present invention is based on such findings, and the method for detecting deterioration of a sealant according to the present invention is a method for detecting deterioration of a sealant arranged between siding boards forming an exterior surface of an exterior wall of a building, and includes a frequency setting step of irradiating the sealant with electromagnetic waves and setting a plurality of frequencies of the electromagnetic waves at which a component of the reflected wave that changes in accordance with a change in hardness of the sealant can be detected from a component of the reflected wave reflected by the sealant; an irradiation and reception step of irradiating the electromagnetic waves at each of the plurality of frequencies at least along the sealant and receiving the reflected waves reflected by the exterior wall for each of the partitioned regions of the sealant; the amplitude ratio and phase difference calculation step of calculating an amplitude ratio of the reflected wave to the amplitude of the electromagnetic wave and a phase difference of the reflected wave to the electromagnetic wave at each of the frequencies; a cluster analysis step of performing a cluster analysis for each of the partitioned areas by using at least one of the amplitude ratio and the phase difference at each of the frequencies to set at least two or more types of clusters for each of the partitioned areas and classify the partitioned areas into one of the set clusters; and a deterioration determination step of determining that the sealing material is partially deteriorated if a plurality of partitioned areas located in the sealing material are classified into two or more types of clusters from the classification results and a predetermined number or more of partitioned areas of the same type of cluster exist consecutively.

[0011] In the method for detecting deterioration of a sealant according to the present invention, first, in the frequency setting step, a plurality of frequencies of electromagnetic waves are set at which a component of a reflected wave that changes according to a change in hardness of the sealant can be detected. In the irradiation and reception step, the electromagnetic waves of the set frequencies are irradiated onto the sealant, so that a component of a reflected wave that changes according to a change in hardness of the sealant can be received. In the amplitude ratio and phase difference calculation step, an amplitude ratio and a phase difference of a reflected wave are calculated from a reflected wave received for each electromagnetic wave irradiated at each frequency. In the cluster analysis step, each divided area including the sealant is classified into one of the clusters using either the amplitude ratio or the phase difference. In the deterioration determination step, when a plurality of divided areas located on the sealant are classified into one of two or more types of clusters from the classification result and a predetermined number or more of divided areas of the same type of cluster exist consecutively, it can be determined that the sealant is partially deteriorated.

[0012] In a more preferred embodiment, in the irradiation and reception process, the electromagnetic waves are irradiated to the sealant and the siding board at each of the multiple frequencies, and the reflected waves reflected by the sealant and the siding board are received for each partitioned area of ​​the sealant and the siding board, and in the cluster analysis process, at least one of the amplitude ratio and the phase difference at each frequency is used for each partitioned area to set at least three or more types of clusters, and a cluster analysis is performed to classify the partitioned area into one of the set clusters.

[0013] According to this embodiment, in the irradiation and reception step, electromagnetic waves are irradiated at each frequency for each partitioned area of ​​the sealant and the siding board, and the reflected waves are received. In the cluster analysis step, at least three or more types of clusters are set for each partitioned area using at least one of the amplitude ratio and phase difference at each frequency, and cluster analysis is performed to classify the partitioned area into one of the set clusters. In this way, by including the partitioned area of ​​the siding board, which is made of a different material from the sealant and has a higher hardness, the sealant can be cluster analyzed more accurately.

[0014] More preferably, in this embodiment, four types of clusters are set in the cluster analysis step. As a result, since new clusters are classified at the boundaries between the sealant and the siding board, where the components of the reflected waves are likely to vary, it becomes easier to classify into clusters according to "deteriorated portion of the sealant," "undeteriorated portion of the sealant," "siding board," and "boundary between the sealant and the siding board."

[0015] In a further preferred embodiment, in the cluster analysis step, the amplitude ratio and the phase difference are complex-converted into a real part and an imaginary part, and the cluster analysis is performed using at least one of the real part and the imaginary part.

[0016] According to this aspect, the cluster analysis unit generates data for each partitioned region, which is obtained by complex-transforming the amplitude ratio and phase difference of the reflected wave at each frequency into a real part and an imaginary part, as data based on the amplitude ratio and phase difference. The complex-transformed real part and imaginary part data are data on the same complex plane. Therefore, by using a combination of these real part and imaginary part data, it is possible to more accurately identify the undeteriorated part of the sealing material.

[0017] The deterioration detection system for a sealant according to the present invention is a deterioration detection system that detects deterioration of a sealant arranged between siding boards that form the exterior surface of an exterior wall of a building, the deterioration detection system comprising: an irradiation and receiving device that irradiates electromagnetic waves to the sealant, and sets a plurality of frequencies of the electromagnetic waves at which components of the reflected waves reflected by the sealant that change in accordance with changes in hardness of the sealant can be detected from components of the reflected waves reflected by the sealant, irradiates the electromagnetic waves at each of the plurality of frequencies at least along the sealant, and receives the reflected waves reflected by the exterior wall, for each of the partitioned regions of the sealant; and a calculation device that performs calculations to detect deterioration of the sealant, the calculation device performing calculations to detect deterioration of the sealant for each of the partitioned regions. The sealing material is characterized by comprising at least an amplitude ratio and phase difference calculation unit that calculates an amplitude ratio of the reflected wave to the amplitude of the received electromagnetic wave at each of the frequencies and a phase difference of the reflected wave to the electromagnetic wave at each of the frequencies; a cluster analysis unit that performs cluster analysis for each of the partitioned areas by using at least one of the amplitude ratio and the phase difference at each of the frequencies to set at least two or more types of clusters for each of the partitioned areas and classify the partitioned areas into one of the set clusters; and a degradation determination unit that determines that the sealing material is partially deteriorated when a plurality of partitioned areas located in the sealing material are classified into two or more types of clusters from the classification results and a predetermined number or more of partitioned areas of the same type of cluster exist consecutively.

[0018] According to the sealant deterioration detection system of the present invention, a plurality of frequencies of electromagnetic waves are set in the irradiation receiving device, which are capable of detecting a component of a reflected wave that changes in accordance with a change in hardness of the sealant. Thus, the irradiation receiving device can receive a component of a reflected wave that changes in accordance with a change in hardness of the sealant by irradiating the sealant with an electromagnetic wave of the set frequency. In the arithmetic device, the amplitude ratio and phase difference calculation unit can calculate an amplitude ratio and a phase difference of the reflected wave from the reflected wave received for each electromagnetic wave irradiated at each frequency. The cluster analysis unit can classify each partitioned area including the sealant into any cluster using either the amplitude ratio or the phase difference. The deterioration determination unit can determine that the sealant is partially deteriorated when a plurality of partitioned areas located in the sealant are classified into any one of two or more types of clusters from the classification result and a predetermined number or more of partitioned areas of the same type of cluster exist consecutively. Effect of the Invention

[0019] According to the present invention, deterioration of a sealing material exposed from an exterior wall can be detected in a non-contact manner. [Brief description of the drawings]

[0020] [Figure 1] The embodiment of the present invention is a schematic perspective view for explaining the relationship between an exterior wall including a sealing material that is a target for deterioration detection and an irradiation receiving device of a deterioration detection system. [Diagram 2] 1 is a schematic diagram of a deterioration detection system according to an embodiment of the present invention. [Diagram 3] FIG. 3 is a block diagram of a calculation device of the deterioration detection system shown in FIG. 2. [Figure 4] 11 is a table showing the amplitude ratio and phase difference calculated by an amplitude ratio and phase difference calculation unit, and a table showing the real part and the imaginary part after complex transformation. FIG. [Diagram 5] 1 is a diagram for explaining a complex transformation performed by a calculation device of the deterioration detection system. [Figure 6] FIG. 13 is a diagram for explaining the relationship between partitioned regions and classified clusters. [Figure 7] 3 is a flow diagram of a deterioration detection method using the deterioration detection system shown in FIG. 2. [Figure 8] FIG. 2A is a diagram for explaining a degradation detection method according to the first embodiment, and FIG. 2B is a diagram showing the results of the method. [Figure 9] FIG. 11A is a diagram for explaining a degradation detection method according to a second embodiment, and FIG. 11B is a diagram showing the results of the method. [Figure 10] FIG. 13A is a diagram for explaining a degradation detection method according to a third embodiment, and FIG. 13B is a diagram showing the results of the method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, a deterioration detection method and a deterioration detection system for detecting deterioration of a sealing material will be described with reference to FIGS.

[0022] 1. Regarding exterior wall 20 As shown in FIG. 1, in this embodiment, the deterioration detection system 10 detects deterioration of a sealing material 22 arranged between siding boards 21, 21 that form an exterior wall surface 21a of an exterior wall 20 of a building from the reflected waves of electromagnetic waves irradiated to the exterior wall 20.

[0023] In the embodiment, the exterior wall 20 is a member corresponding to the exterior wall of a building to be inspected. In this embodiment, the building is a wooden house or a steel frame house, and the exterior wall 20 is an exterior wall structure of the building in which a plurality of siding boards 21, 21 are provided on the exterior side and a plaster board 28 is provided on the interior side.

[0024] Examples of the siding board 21 include ceramic siding boards formed into a board shape using cementitious and fibrous raw materials as main raw materials, and metal siding boards processed from metal materials. The ceramic siding boards may be any of wood fiber reinforced cement boards, fiber reinforced cement boards, and fiber reinforced cement-calcium silicate boards.

[0025] The sealant 22 may be either a fixed sealant or an amorphous sealant, and the material may be a resin material that utilizes mixed reaction hardening or moisture hardening, such as a silicone-based, modified silicone-based, polysulfide-based, acrylic urethane-based, or polyurethane-based material, or a material that utilizes dry hardening, such as an acrylic-based, SBR-based, or butyl rubber-based material, and is not particularly limited as long as the hardness of the sealant 22 changes due to deterioration.

[0026] A sealant 22 is filled between the siding boards 21, 21 forming the outer wall surface 21a of the outer wall 20. For example, a wood board may be provided between the siding board 21 and the gypsum board 28 as a structural plywood. In this embodiment, a vertical furring strip 24 and a stud 25 are arranged between the siding board 21 and the gypsum board 28. Furthermore, an insulating board 26 made of a foamed resin board such as polystyrene foam is arranged between the siding board 21 and the gypsum board 28. A fireproof material (fiber-based fireproof material) such as glass wool may be arranged instead of the insulating board 26. In this embodiment, an air-permeable fastening metal fitting 23 is arranged between the insulating board 26 and the sealant 22, and an air-permeable layer is formed between the siding board 21 and the insulating board 26. A metal or resin joint joiner that joins the siding boards 21, 21 together may be arranged on the back side of the sealant 22.

[0027] In addition, as shown in Fig. 8(a), a metal plate 23A may be disposed on the back surface of the sealing material 22. Also, as shown in Fig. 9(a), a heat insulating board 26 may be disposed on the back surface of the sealing material 22, and a metal plate 23A may be disposed on the back surface of the heat insulating board. Furthermore, as shown in Fig. 10(a), a plywood 24A may be disposed on the back surface of the sealing material 22, and a metal plate 23A may be disposed on the back surface of the plywood 24A.

[0028] 2. Hardware of the Deterioration Detection System 10 The deterioration detection system 10 includes an irradiation receiving device 3 that performs non-destructive testing of the sealing material 22 of the exterior wall 20 described above using electromagnetic waves B. As shown in Fig. 1, the irradiation receiving device 3 irradiates electromagnetic waves B of different frequencies each having a certain amplitude from the exterior wall surface 21a of the exterior wall 20 toward the inside of the exterior wall 20, and receives reflected waves C reflected by the exterior wall 20 at each frequency, for each divided area A of the exterior wall surface 21a of the exterior wall 20.

[0029] The irradiation receiving device 3 includes a housing 15. A handle 17 that an operator holds is provided on one side of the housing 15. Wheels 13 are provided on the other side of the housing 15 at a position facing an outer wall 20, which is an object to be inspected. A transmitter 11 and a receiver 12 are disposed inside the housing 15.

[0030] The transmitter 11 is a device that irradiates the exterior wall 20 with electromagnetic waves B having a constant amplitude and a constant frequency while gradually changing the frequency of the electromagnetic waves B. The housing 15 is provided with a control device (not shown) that gradually changes the frequency of the electromagnetic waves B of the transmitter 11, which will be described later. The transmitter 11 irradiates the electromagnetic waves B while gradually changing the frequency of the electromagnetic waves B by the control device in accordance with the rotation speed of the wheels 13. This allows the irradiation receiving device 3 (transmitter 11) to irradiate electromagnetic waves B of a plurality of different frequencies to each of the partitioned areas A partitioned on the wall surface of the exterior wall 20, which will be described later.

[0031] 2, in this embodiment, the transmitter 11 is preset with a plurality of frequencies of the electromagnetic waves B for each partitioned region A of the exterior wall 20, at which the electromagnetic waves B are irradiated onto the sealing material 22 and the component of the reflected wave C reflected by the sealing material 22 can be detected, the component of the reflected wave C varying in accordance with the change in hardness of the sealing material 22. These frequencies of the electromagnetic waves B can be preset by experiments or the like.

[0032] For example, in this embodiment, as described later with reference to FIG. 5, seven different frequencies F1 to F7 are set in advance, but the number of these frequencies is not particularly limited as long as the component of the reflected wave C reflected by the sealing material 22 that changes according to the change in hardness of the sealing material 22 can be detected. In addition, five frequencies obtained in advance by experiments are set in the following Examples 1 to 3. In addition, the calculation device 4 described later may extract only data of the reflected wave C when the frequency is changed stepwise while being irradiated. The frequency band of the set frequency is preferably, for example, in the range of 7.0 GHz to 12.0 GHz, and multiple different frequencies can be set within this frequency band.

[0033] The receiver 12 is a device that receives reflected waves C that are the result of the electromagnetic waves B transmitted from the transmitter 11 being reflected by the exterior wall 20 (specifically, the siding board 21 and the sealing material 22). Here, the electromagnetic waves transmitted (irradiated) by the transmitter 11 include those that are reflected by the surface of the object to be inspected and those that are reflected after being refracted, attenuated, and transmitted inside the object to be inspected. The receiver 12 receives the waves that are the result of physical interference between these reflected waves as reflected waves C. The reflected waves C that are reflected inside the object to be inspected have changed amplitude and frequency relative to the electromagnetic waves B. The received reflected waves C are recorded in a storage device (not shown) provided in the housing 15 or a storage device (not shown) provided together with the computing device 4.

[0034] The deterioration detection system 10 includes a calculation device 4 that performs calculations for detecting deterioration of the sealing material 22, and a display device 5 that displays the results of the calculations performed by the calculation device 4. In this embodiment, the calculation device 4 and the display device 5 are provided separately from the irradiation receiving device 3, but may be provided integrally with the irradiation receiving device 3.

[0035] 3. Software for Calculation Unit 4 In FIG. 3, the arithmetic device 4 includes at least an amplitude ratio phase difference calculation section 4A, a cluster analysis section 4B, and a deterioration determination section 4C.

[0036] 3-1. Amplitude ratio phase difference calculation unit 4A The amplitude ratio and phase difference calculation unit 4A calculates the amplitude ratio of the reflected wave to the amplitude of the electromagnetic wave B at each frequency received for each divided area A, and the phase difference of the reflected wave C to the electromagnetic wave B at each frequency. Here, since the reflected wave C is a waveform in which multiple frequencies are synthesized, the frequency that is the main component of the reflected wave C (i.e., the frequency with the highest spectrum (largest amplitude)) is identified by frequency analysis using FFT, and the amplitude ratio L and phase difference P are calculated from the amplitude and phase of the reflected wave C at the identified frequency. Note that the reflected wave C may be directly received, the peak of the received waveform may be used as the amplitude, and the phase of the peak period may be obtained, and the amplitude ratio L and phase difference P may be calculated from these amplitudes and phases. FIG. 4 shows the calculated amplitude ratios L1, L2, ..., L7 and phase differences P1, P2, ..., P7 for seven frequencies (measurement frequencies) F1, F2, ..., F7.

[0037] 3-2. About Cluster Analysis Section 4B The cluster analysis unit 4B performs cluster analysis for each divided region A, classifying each divided region A into a plurality of clusters, using at least one of the amplitude ratio L and the phase difference P at each frequency F1 to F7. Cluster analysis may be performed using only the amplitude ratio L at each frequency F1 to F7, or may be performed using only the phase difference P at each frequency F1 to F7. Even in these cases, according to the experiments of the inventors, it has been found that deteriorated parts of the sealing material can be detected. However, in this embodiment, the cluster analysis is performed as follows. Specifically, the cluster analysis unit 4B includes a complex conversion unit 41, an identification data allocation unit 42, and a cluster classification unit 43.

[0038] 3-2-1. About the complex transform unit 41 The complex transformation unit 41 performs complex transformation on the amplitude ratios L1, L2, ..., L7 and phase differences P1, P2, ..., P7 at the frequencies F1, F2, ..., F7 for each divided region A. Specifically, as shown in Fig. 5, a point T corresponding to the amplitude ratio L and phase difference P is plotted on a complex plane, and the values ​​of the real part R and the imaginary part K on the real axis and the imaginary axis are calculated.

[0039] 4, it is possible to obtain the calculated real parts R1, R2, ..., R7 and the imaginary parts K1, K2, ..., K7 for each of the seven frequencies (measurement frequencies) F1, F2, ..., F7. These results are identification data for identifying the deterioration of the sealing material 22.

[0040] Since the identification data of the complex-transformed real and imaginary parts are identification data on the same complex plane, by using a combination of these identification data, it is possible to identify a combination of identification data elements that can more accurately identify the condition of the exterior wall 20.

[0041] 3-2-2. Identification data allocation unit 42 The identification data allocation unit 42 allocates, for each divided area A, the real and imaginary parts that are correlated with the change in hardness of the sealant 22, among the complex-converted real and imaginary parts. Specifically, for each divided area A, as identification data based on the amplitude ratios L1, L2, ..., L7 and phase differences P1, P2, ..., P7 at each frequency F1, F2, ..., F7, the real and imaginary parts that are correlated with the change in hardness of the sealant 22 are extracted (selected) from the calculated real parts R1, R2, ..., R7 and imaginary parts K1, K2, ..., K7, and the values ​​of the extracted real and imaginary parts are allocated to each divided area A. The extracted real and imaginary parts may be selected in advance by preparing a test specimen with the same structure as the exterior wall 20 and performing a similar cluster analysis, so that the deteriorated and undeteriorated parts of the sealant can be identified.

[0042] 3-2-3. Cluster Classification Unit 43 Here, the complex-transformed real and imaginary parts are classified into a plurality of clusters using the real and imaginary parts assigned to each partitioned area. Here, when partitioned area A is composed only of sealant 22, two clusters may be set so that the "deteriorated portion of the sealant" and the "undeteriorated portion of the sealant" can be detected.

[0043] 1, in this embodiment, not only the sealant 22 but also the siding board 21 are included in the range of the divided area A. In this way, by including the siding board 21, which is made of a different material and has a higher hardness than the sealant 22, in the divided area A, not only the siding board 21 but also the sealant 22 are identified by cluster analysis, so that the reliability of detecting the position of the sealant 22 and its deteriorated portion can be improved.

[0044] Here, when the sealant 22 and the siding board 21 are defined as the partitioned area A, it is sufficient to classify into clusters according to "deteriorated portion of the sealant", "undeteriorated portion of the sealant", and "siding board". Therefore, it is preferable to set the cluster classification unit 43 to three or more types of clusters (three or more classes), and it is preferable to set it to five or less types of clusters (five or less classes).

[0045] From experiments etc. conducted by the inventors described later, it was found that the "boundary between the sealant 22 and the siding board 21" also has an effect on the component of the reflected wave C. This makes it easier to classify into clusters according to the "deteriorated portion of the sealant 22," the "undeteriorated portion of the sealant 22," the "siding board 21," and the "boundary between the sealant 22 and the siding board 21."

[0046] As shown in Fig. 6, each partitioned area A of the exterior wall surface 21a is a rectangular area divided into 12 vertical sections and 10 horizontal sections, with 12 rows and 10 columns. In this example, the "siding board 21" of the exterior wall 20, the "deteriorated portion of the sealant 22," the "undeteriorated portion of the sealant 22," and the "boundary between the sealant 22 and the siding board 21" are assumed.

[0047] In this case, four types of clusters are set. As a result, the cluster classification results are, for example, the divided area A of the "siding board 21" is classified into cluster "1", the divided area A of the "deteriorated part of the sealant 22" is classified into cluster "2", the divided area A of the "undeteriorated part of the sealant 22" is classified into cluster "3", and the divided area A of the "boundary between the sealant 22 and the siding board 21" is classified into cluster "4". Specifically, when performing the cluster analysis, a non-hierarchical cluster analysis may be performed by the k-means method, or the divided area A may be classified into which type of cluster it belongs by other cluster analysis such as the EM algorithm. Note that, when the materials of the siding board 21 are different in the multiple divided areas A, further types of clusters may be added according to the number of types.

[0048] Note that the correspondence between clusters "1" to "4" is set for convenience in the order of "siding board 21," "deteriorated portion of sealing material 22," "undeteriorated portion of sealing material 22," and "boundary between sealing material 22 and siding board 21," and these correspondences can be changed as appropriate.

[0049] 3-2-4. Cluster Classification Result Allocation Unit 44 As a result of ideal cluster analysis, the three rows of partitioned areas A on the left and right are assigned cluster "1", the upper half of the two central rows are assigned cluster "2", and the lower half are assigned cluster "3", as shown in Fig. 6. Furthermore, cluster "4" is assigned to the partitioned areas A between cluster "1" and cluster "2", and between cluster "1" and cluster "3".

[0050] 3-3. Deterioration judgment unit 4C The deterioration determination unit 4C determines that the sealing material 22 is partially deteriorated when, based on the classification results, multiple partitioned areas A located in the sealing material 22 are classified into one of the four types of clusters "1" to "4" and a predetermined number or more of partitioned areas A of the same type of cluster exist consecutively.

[0051] Specifically, as shown in Fig. 6, depending on the scanning position of the irradiation receiving device 3 relative to the exterior wall surface 21a of the exterior wall 20, the three left and right rows of divided areas A to which cluster "1" is assigned can be estimated to be siding board 21. Of the two central rows, the upper half of the divided area A to which cluster "2" is assigned and the lower half of the divided area A to which cluster "3" is assigned can be estimated to be sealing material 22. Furthermore, the divided areas A between clusters "1" and "2" and between clusters "1" and "3" to which cluster "4" is assigned can be estimated to be "boundaries between the sealing material 22 and the siding board 21".

[0052] Here, in the divided area A estimated to be sealing material 22, clusters "2" and "3" exist, and when a predetermined number or more (for example, four or more) of divided areas A of the same type of clusters "2" and "3" exist consecutively, it can be determined that either of the divided areas A assigned with cluster "2" or "3" is a deteriorated sealing material 22. Therefore, the deterioration determination unit 4C can determine that the sealing material 22 is partially deteriorated.

[0053] When identifying which sealant 22 in the divided area A assigned to cluster "2" or "3" has deteriorated, the deterioration determination unit 4C may pre-record the range of the exterior wall surface that is more deteriorated from the range irradiated by sunlight, the range directly exposed to rainwater, the range that is easily exposed to moisture, etc. The deterioration determination unit 4C can determine which of the divided areas A assigned to cluster "2" or "3" contains the deteriorated sealant 22 from the divided area A assigned to cluster "2" or "3" and the range of more deteriorated.

[0054] A method for determining the deterioration of the sealing material 22 will be described below with reference to the flow chart of FIG. First, in step S11, a control device (not shown) of the irradiation receiving device 3 irradiates the sealing material 22 with electromagnetic waves B, and sets a plurality of frequencies of the electromagnetic waves B that can obtain a component of the reflected wave C that changes in accordance with the change in hardness of the sealing material 22 from the component of the reflected wave reflected by the sealing material 22. Specifically, a sample of the sealing material 22 whose hardness has changed due to deterioration is prepared, and such a frequency of the electromagnetic waves B is experimentally determined.

[0055] Next, in step S12, an irradiation and reception process is performed. Specifically, electromagnetic waves B are irradiated to the exterior wall 20 and reflected waves C are received. Specifically, as shown in Fig. 1, electromagnetic waves B having a certain amplitude and a certain frequency are irradiated from the exterior wall surface 21a of the exterior wall 20 toward the inside of the exterior wall 20 along at least the sealing material 22, and while the frequency of the electromagnetic waves B is changed stepwise, reflected waves C reflected by the exterior wall 20 are received at each frequency (for example, for each of seven different frequencies). This operation is performed for each partitioned area A of the exterior wall surface 21a of the exterior wall 20.

[0056] The irradiation of the electromagnetic waves B and the reception of the reflected waves C for each divided area A are performed by holding the handle 17 of the irradiation receiving device 3 shown in FIG. 1, pressing the wheels 13 of the irradiation receiving device 3 against the outer wall surface 21a, and moving (scanning) the irradiation receiving device 3 in the vertical direction (or horizontal direction) while rotating the wheels 13 on the outer wall surface 21a. This allows the irradiation receiving device 3 to irradiate the electromagnetic waves B with a stepwise changed frequency for each divided area A and receive the reflected waves C for each frequency. The same operation is repeated by shifting in the horizontal direction (or vertical direction). The frequency of the electromagnetic waves B is, for example, the seven different frequencies described above, and the measurement frequency is changed stepwise for each divided area A.

[0057] In step S13, an amplitude ratio phase difference calculation step is performed. In this step, the amplitude ratio L of the reflected wave C at each frequency and the phase difference P of the reflected wave C relative to the electromagnetic wave B at each frequency, which are received for each divided area A, are calculated by the amplitude ratio phase difference calculation unit 4A of the calculation device 4. As a result, the calculated amplitude ratios L1, L2, ..., L7 and phase differences P1, P2, ..., P7 are calculated for each of the seven frequencies (measurement frequencies) F1, F2, ..., F7.

[0058] Next, in steps S14 to S17, a cluster analysis process is performed. First, in step S14, the complex conversion unit 41 of the cluster analysis unit 4B performs complex conversion on the amplitude ratios L1 to L7 and the phase differences P1 to P7 at the frequencies F1 to F7 for each divided area A. As a result, real parts R1 to R7 and imaginary parts K1 to K7 can be obtained. Of these, real parts and imaginary parts common to each divided area A that can identify whether the sealing material 22 is deteriorated or not are extracted. As such real parts and imaginary parts, for example, identification data such as real parts R1, R3, R4, and R6 and imaginary parts K2, K3, K5, and K7 are extracted for each divided area A. This extracted data is the component of the reflected wave that changes according to the change in hardness of the sealing material 22 when setting the frequency of the electromagnetic wave B in the above-mentioned step S11.

[0059] Next, the process proceeds to step S15, where the identification data allocation section 42 of the cluster analysis section 4B allocates the extracted identification data to each partitioned area A. Next, the process proceeds to step S16, where the cluster classification section 43 of the cluster analysis section 4B sets four types of clusters "1" to "4" (four classes), and classifies the multiple partitioned areas A into one of the set clusters "1" to "4" using the extracted identification data of the real and imaginary parts.

[0060] Next, in step S18, a deterioration determination step is performed. In this step, if the classification results show that a plurality of divided regions A located in the sealing material 22 are classified into one of two or more types of clusters and a predetermined number or more of divided regions of the same type of cluster exist consecutively, the deterioration determination unit 4C determines that the sealing material 22 is partially deteriorated. Finally, a series of results are output to the display device 5.

[0061] The inventors prepared a specimen of an exterior wall in which a sealant whose upper half was deteriorated was arranged, as shown in Fig. 8(a) to Fig. 10(a). In Example 1 shown in Fig. 8(a), a specimen was prepared in which a sealant 22 was filled between a pair of siding boards 21, 21, and a metal plate 23A was laid on the back surface of the pair of siding boards 21, 21. In Example 2 shown in Fig. 9(a), a specimen was prepared in which a sealant 22 was filled between a pair of siding boards 21, 21, and a heat insulating board 26 and a metal plate 23A were laid on the back surface of the pair of siding boards 21, 21. In Example 3 shown in Fig. 10(a), a specimen was prepared in which a sealant 22 was filled between a pair of siding boards 21, 21, and a heat insulating board 26 and a metal plate 23A were laid on the back surface of the pair of siding boards 21, 21.

[0062] The specimens of Examples 1 to 3 were irradiated with electromagnetic waves of five different frequencies F1 to F5 for each divided area A. Specifically, the frequencies F1 to F5 are 8.4 GHz, 9.2 GHz, 10.4 GHz, 10.8 GHz, and 11.2 GHz, respectively. These frequencies are capable of detecting the change in hardness of the sealant 22, and were previously obtained through experiments or the like. However, in the case of Examples 1 to 3 as an example, the frequencies are not limited to these frequencies, and it has been found that even if two or more of these five frequencies are selected, it is possible to identify the tendency of partial deterioration of the sealant 22, and the number of frequencies is not limited to these frequencies. For example, in the case of Examples 1 to 3 as an example, it has been found from the inventors' experience that almost the same results can be obtained even if these frequencies are within a range of ±0.1 GHz. Amplitude ratios L1 to L5 and phase differences P1 to P5 were measured from the received reflected waves, and these were then complex transformed to calculate real parts R1 to R5 and imaginary parts K1 to K5 according to frequencies F1 to F5.

[0063] Using the real parts R3 and R4 and the imaginary parts K1 to K5, four types of clusters (four classes) were set for the multiple partitioned regions A, and cluster analysis was performed using the k-means method. The results for the test specimens of Examples 1 to 3 are shown in Figures 8(b) to 10(b).

[0064] As shown in FIG. 8(b), the sealant of Example 1 was found to be in the partitioned areas of cluster "2" and cluster "4". As shown in FIG. 9(b), the sealant of Example 2 was found to be in the partitioned areas of cluster "3" and cluster "4". As shown in FIG. 10(b), the sealant of Example 3 was found to be in the partitioned areas of cluster "4" and cluster "1". In this way, it can be said that the deterioration of the sealant 22 can be detected because it is classified into two clusters regardless of the members arranged on the back surface of the pair of siding boards 21, 21. In addition, if the parts that are prone to deterioration are set in advance based on the use environment of the sealant, it is possible to identify which cluster's partitioned area the sealant part is deteriorated.

[0065] As described above, according to the present embodiment, the use of electromagnetic waves in the microwave region provides high safety. Furthermore, partial deterioration can be detected before the entire sealant deteriorates, so maintenance can be performed at an appropriate time. Furthermore, if the device is mounted on an unmanned aerial vehicle such as a drone, deterioration of the sealant at high places can be detected safely and quickly.

[0066] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various design modifications can be made without departing from the spirit of the present invention as described in the claims. [Explanation of symbols]

[0067] 3: irradiation receiving device, 4: calculation device, 4A: amplitude ratio phase difference calculation unit, 4B: cluster analysis unit, 4C: deterioration determination unit, 10: deterioration detection system, 20: exterior wall, 21: siding board, 22: sealant, A: partition area, B: electromagnetic wave, C: reflected wave, F: frequency, L: amplitude ratio, P: phase difference, R: real part, K: imaginary part

Claims

1. A method for detecting deterioration of a sealant disposed between siding boards forming an exterior surface of an exterior wall of a building, comprising: a frequency setting step of irradiating the sealing material with electromagnetic waves and setting a plurality of frequencies of the electromagnetic waves at which a component of the reflected wave that changes in response to a change in hardness of the sealing material can be detected from a component of the reflected wave reflected by the sealing material; an irradiation and reception process for performing the irradiation of the electromagnetic waves for each of the plurality of frequencies at least along the sealing material and receiving the reflected waves reflected by the exterior wall for each partitioned area of ​​the sealing material; an amplitude ratio and phase difference calculation step of calculating an amplitude ratio of the reflected wave to the amplitude of the electromagnetic wave at each of the frequencies received for each of the partitioned regions, and a phase difference of the reflected wave to the electromagnetic wave at each of the frequencies; a cluster analysis step of setting at least two or more types of clusters for each of the divided regions using at least one of the amplitude ratio and the phase difference at each of the frequencies, and performing a cluster analysis to classify the divided regions into one of the set clusters; and a deterioration determination process for determining that the sealant is partially deteriorated if, based on the classification results, a plurality of partitioned areas located in the sealant are classified into one of two or more types of clusters and a predetermined number or more of partitioned areas of the same type of cluster exist in succession.

2. In the irradiation and reception step, the electromagnetic waves are irradiated to the sealant and the siding board for each of the plurality of frequencies, and the reflected waves reflected by the sealant and the siding board are received for each partitioned area of ​​the sealant and the siding board; The method for detecting deterioration of a sealing material as described in claim 1, characterized in that in the cluster analysis process, for each divided area, at least one of the amplitude ratio and the phase difference at each frequency is used to set at least three or more types of clusters for each divided area, and a cluster analysis is performed to classify the divided area into one of the set clusters.

3. 3. The method for detecting deterioration of a sealing material according to claim 2, wherein in the cluster analysis step, four types of clusters are set.

4. 2. The method for detecting deterioration of a sealing material according to claim 1, wherein in the cluster analysis step, the amplitude ratio and the phase difference are complex-transformed into a real part and an imaginary part, and the cluster analysis is performed using at least one of the real part and the imaginary part.

5. A deterioration detection system for detecting deterioration of a sealant disposed between siding boards forming an exterior wall surface of an exterior wall of a building, comprising: The deterioration detection system includes: an irradiation and receiving device that irradiates electromagnetic waves onto the sealant, sets a plurality of frequencies of the electromagnetic waves at which components of the reflected waves reflected by the sealant that change in accordance with changes in hardness of the sealant can be detected, irradiates the electromagnetic waves at each of the plurality of frequencies at least along the sealant, and receives the reflected waves reflected by the exterior wall for each of the partitioned regions of the sealant; A calculation device that performs a calculation to detect deterioration of the sealing material, The computing device includes: an amplitude ratio and phase difference calculation unit that calculates an amplitude ratio of the reflected wave to the amplitude of the electromagnetic wave at each of the frequencies received for each of the partitioned regions and a phase difference of the reflected wave to the electromagnetic wave at each of the frequencies; a cluster analysis unit that performs a cluster analysis to set at least two or more types of clusters for each of the divided regions using at least one of the amplitude ratio and the phase difference at each of the frequencies and classify the divided regions into one of the set clusters; and a deterioration determination unit that determines that the sealant is partially deteriorated if, based on the classification results, a plurality of partitioned areas located in the sealant are classified into one of two or more types of clusters and a predetermined number or more of partitioned areas of the same type of cluster exist in succession.

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