JP3787751B2 - Damage evaluation method for load support for magnetic levitation train - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a damage evaluation method for a load support for a magnetic levitation train, and in particular, a damage evaluation suitable for inspection such as peeling of an FRP and a metal bonding surface of a load support supporting a superconducting coil and damage of an FRP portion. Regarding the method.
[0002]
[Prior art]
A conventional example of a peeling evaluation technique for an adhesive interface is ultrasonic flaw detection. One example is “Development of High-Speed Ultrasonic Inspection Apparatus and Application to Joints” on pages 195 to 198 of the collection of lectures at Welding Structure Symposium 95. This means that with respect to the peeling of the adhesive interface, the peeled portion can be detected in a short time by ultrasonic flaw detection.
[0003]
[Problems to be solved by the invention]
An FRP / metal bonding structure is used for the load support of the superconducting magnet. Since this adhesion part receives various loads, it is expected that the adhesion part peels off during traveling. Therefore, it is necessary to quantitatively evaluate the separation occurrence and the separation length of the bonded portion. Moreover, it is necessary to evaluate the damage of the FRP part.
[0004]
However, since the load support is stored in the vacuum vessel, it cannot be taken out and applied to the ultrasonic flaw detector. There is a need for a method for quantitatively evaluating the peeled state of the bonding interface between the FRP and the metal fitting while the load support is housed in the vacuum vessel. Therefore, it is necessary to monitor the load and strain and evaluate the damage based on the values.
[0005]
In addition, since the magnetic suspension train load support is used in a strong magnetic field, harmonic noise is generated in an electrical signal such as a strain gauge. Therefore, it is necessary to evaluate the peeling of the bonded portion based on a force that is not affected by harmonics such as a direct current force.
[0006]
Therefore, an object of the present invention is to quantitatively evaluate the occurrence of separation and the separation length of a load support bonded portion by using a strain gauge based on direct current forces such as levitation force, propulsion force, and excitation force. It is something to try. Further, the same method is used to evaluate the damage of the FRP part.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention intends to evaluate damage to the FRP part itself by disposing a strain gauge in the FRP part of the load support in the load support for a magnetic levitation train. In addition, by installing strain gauges on the inner tank side and the outer tank side in the vicinity of the bonding part where the FRP cylindrical body is bonded to the metal plate metal fitting, let's quantitatively evaluate the occurrence of peeling and the separation length of the bonding part. It is what.
[0008]
That is, a strain gauge is appropriately attached to a predetermined position near the adhesive portion of the FRP tubular body, and based on the detected strain, based on the DC force at the time of levitation, propulsion, excitation, etc. of the magnetic levitation train, Evaluate the occurrence of debonding and the debonding length of the bonded part. In addition, damage to the FRP unit itself is also evaluated using a similar method.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 and 2 show an embodiment of the present invention, FIG. 1 is a view in which a strain gauge is attached to a load support, and FIG. 2 is a view showing the structure of a superconducting magnet of a magnetic levitation train.
[0010]
As shown in these drawings, the load support 7 serves to connect the cryogenic inner tank 6 in which the superconducting coil 9 is housed with the outer tank 8 that keeps the surroundings in a vacuum state. The structure of the load support 7 has a structure in which the end of an FRP cylinder (hereinafter also referred to as FRP1) having a diameter at the center smaller than the diameter at both ends is embedded in the metal plate fitting 2 and bonded.
[0011]
In such a superconducting magnet for a magnetic levitation train, strain gauges 4 and 5 are affixed in the vicinity of the bonding portion 3 between the metal plates 2 at both ends of the FRP 1. Since the bonding portion 3 of the load support body receives various loads, it is expected that the bonding portion peels off. Since the stress concentration in the bonded portion is an extremely small region, it is better to attach a strain gauge as close to the bonded portion as possible. Since there are a room temperature side (outer tub) and a low temperature side (inner tub), there are strain gauges on both sides of the load support. The strain gauges 4 and 5 should be as short as possible.
[0012]
The structure of the superconducting magnet is shown in FIG. The load support 7 connects the cryogenic inner tank 6 and the room temperature outer tank 8. An outer tub 8 is coupled to the carriage 10. Two load supports 7 are attached to the top and bottom of the left and right central part of the inner tank. Here, the strain gauges are disposed on the room temperature side and the low temperature side, respectively, and a total of four strain gauges are pasted on the upper and lower portions in the vertical direction, that is, at the 12 o'clock position and the 6 o'clock position.
[0013]
Next, the peeling evaluation method of an adhesion part is demonstrated about the strain gauge of the room temperature side. When the magnetic levitation train moves from wheel running to levitation running, the levitation force works in the vertical direction as shown. Since the load support 7 supports the inner tank 6 from the outer tank 8 in the form of a cantilever, the strain gauge 4 at the 12 o'clock position is compressed, and the strain gauge 5 at the 6 o'clock position is subjected to tensile strain. To do.
[0014]
FIG. 3 and FIG. 4 are diagrams showing changes in strain over time. In the strain gauge at the 12 o'clock position, the strain change shown in FIG. 4 occurs in the strain gauge at the 6 o'clock position. When measuring this distortion, it is better to pass a low-pass filter of about 5 Hz in order to cut out the harmonic components. 3 and 4 is generated in proportion to the weight of the vehicle body. Therefore, even if the number of passengers changes, it can be converted by weight.
[0015]
Next, a method for evaluating the occurrence of debonding at the bonded portion will be described with reference to FIG. First, the strain εL at the time of initial levitation in FIGS. 3 and 4 is measured. Thereafter, the strain εN is measured every time the vehicle floats. If the body weight is different, the same body weight is set. Then, the values of εN and εL are compared. If the values of εN and εL are the same, no peeling occurs. Separation occurs when the values of εN and εL are different.
[0016]
Next, a method for measuring the peel length will be described with reference to FIG. Since the strain gauges 4 and 5 are affixed in the very vicinity of the bonding part 3, stress concentration occurs. When the bonded portion is peeled off, the strain gauge is separated from the stress concentration portion, so that the strain decreases with the peeling length as shown in FIG.
[0017]
This relationship is obtained in advance by analysis and experiment. As in the case of delamination, the strain at the time of rising is measured as shown in FIGS. The peel length can be obtained by comparing this strain with the value shown in FIG.
[0018]
Another embodiment will be described with reference to FIG. This embodiment is a method for evaluating the damage of the FRP portion based on the strain at the time of the magnetic levitation train ascent. As shown in FIG. 7, strain gauges are pasted at 12:00 and 6 o'clock in the vertical direction of the FRP section. At this time, as long as it is on the line at 12:00 and 6 o'clock, any number of strain gauges may be attached. Moreover, you may affix on both the room temperature side and the low temperature side.
[0019]
In this case, just as there is no stress concentration at the bonded portion, as in the example of FIG. 1, compression occurs at the 12 o'clock position on the room temperature side, and tensile force acts at the 6 o'clock position. The damage of the FRP part is evaluated by the following procedure as in the example of FIG.
[0020]
Measure the strain εL at the time of initial ascent. Thereafter, the strain εN is measured every time the vehicle floats. If the body weight is different, the same body weight is set. Then, the values of εN and εL are compared. If the values of εN and εL are the same, the FRP part is not damaged. If the values of εN and εL are different, the FRP portion is damaged.
[0021]
Another embodiment will be described with reference to FIGS. 8 and 9. This example is a method for evaluating the peeling of the bonded portion based on the driving force. FIG. 8 is a horizontal sectional view of the superconducting magnet. Strain gauges are affixed at the 3 o'clock and 9 o'clock positions in the train traveling direction front and rear, where stress concentration is applied near the bonded portion of the load support 7. A strain gauge is attached to both the room temperature side and the low temperature side.
[0022]
If the driving force is applied as shown in FIG. 8, the strain gauge 4 receives compression and the strain gauge 5 receives tensile force. Among these, the time change of the strain gauge 5 receiving the tensile force is as shown in FIG.
[0023]
After the magnetic levitation train is subjected to tensile strain during acceleration, the strain becomes zero during constant speed operation. After that, since the force works in the opposite direction during deceleration, it receives compression strain. This strain is a value proportional to the acceleration. The strain εN is measured, and the peeling of the bonded portion can be evaluated by the procedure shown in FIG. Similarly, damage to the FRP portion can be evaluated.
[0024]
Still another embodiment will be described with reference to FIGS. 10 and 11. This example is a method for evaluating the peeling of the bonded portion based on the exciting force. In the superconducting magnet outer tub, four superconducting coils are housed side by side in the train traveling direction. These four coils are excited so as to be in the order of S pole, N pole, S pole, and N pole. At this time, since an attractive force acts between the S pole and the N pole, the room temperature side strain gauge 4 is compressed, and the strain gauge 5 is a tensile force.
[0025]
The time change of the strain gauge 5 is as shown in FIG. Tensile strain acts during the excitation state, and the strain becomes zero when demagnetized. The strain εN is measured, and the peeling of the bonded portion can be evaluated in the same procedure as in FIG. Similarly, damage to the FRP portion can be evaluated.
[0026]
【The invention's effect】
As described above, according to the present invention, in the magnetic levitation train, it is possible to determine the occurrence of separation between the FRP of the load support and the bonding surface of the metal fitting, and the separation length. Moreover, the damage of the FRP part can be evaluated.
[Brief description of the drawings]
FIG. 1 shows an embodiment of the present invention, and is a view in which a strain gauge is affixed in the vicinity of a load support bonded portion.
FIG. 2 is a diagram showing the structure of a superconducting magnet in a magnetic levitation train.
FIG. 3 is a diagram showing a change over time of a distortion at a position at 12 o'clock.
FIG. 4 is a diagram showing a change over time in distortion at the 6 o'clock position.
FIG. 5 is a diagram showing an evaluation method of peeling.
FIG. 6 is a diagram showing the relationship between strain ε and peel length a obtained by analysis and experiment.
FIG. 7 is a view showing another embodiment of the present invention in which a strain gauge is attached to the FRP portion.
FIG. 8 is a horizontal cross-sectional view when the peeling is evaluated by the propulsive force.
FIG. 9 is a diagram showing a change with time when a propulsive force is applied to a strain gauge at a position on the room temperature side at 9 o'clock.
FIG. 10 is a horizontal sectional view when peeling is evaluated by exciting force.
FIG. 11 is a diagram showing a change in strain over time when the exciting force is a room-temperature tensile force.
[Explanation of symbols]
1 FRP
2 Hardware (metal plate)
3 Bonding part 4, 5 Strain gauge 6 Inner tank 7 Load support 8 Outer tank 9 Superconducting coil 10 Carriage

Claims (6)

And the inner tub of the cold side to store the superconductive coil of a magnetic levitation train, between the outer tub room temperature side to keep the outside of the inner tub in a vacuum state, bonding the metal plate on both ends of F RP made cylindrical body A method of evaluating damage of a load support formed by fastening with a load support having a structure, wherein the magnetic levitation is performed by strain gauges arranged on the inner tank side and the outer tank side of the FRP tubular body. A damage evaluation method for a load carrier for a magnetically levitated train, comprising: detecting a strain generated in the FRP tubular body when the train is levitated and evaluating the damage of the FRP tubular body. And the inner tub of the cold side to store the superconductive coil of a magnetic levitation train, between the outer tub room temperature side to keep the outside of the inner tub in a vacuum state, bonding the metal plate on both ends of F RP made cylindrical body A method of evaluating damage of a load support formed by fastening with a load support having a structure, wherein the magnetic levitation is performed by strain gauges arranged on the inner tank side and the outer tank side of the FRP tubular body. A damage evaluation method for a load support for a magnetically levitated train, comprising: detecting strain generated in the FRP tubular body during train propulsion to evaluate damage to the FRP tubular body. And the inner tub of the cold side to store the superconductive coil of a magnetic levitation train, between the outer tub room temperature side to keep the outside of the inner tub in a vacuum state, bonding the metal plate on both ends of F RP made cylindrical body A method of evaluating damage of a load support formed by fastening with a load support having a structure, wherein the magnetic levitation is performed by strain gauges arranged on the inner tank side and the outer tank side of the FRP tubular body. A damage evaluation method for a load support for a magnetically levitated train, comprising: detecting strain generated in the FRP tubular body during train excitation to evaluate damage to the FRP tubular body. And the inner tub of the cold side to store the superconductive coil of a magnetic levitation train, between the outer tub room temperature side to keep the outside of the inner tub in a vacuum state, bonding the metal plate on both ends of F RP made cylindrical body A method of evaluating damage to a load support formed by fastening with a load support having a structure, in the vicinity of the metal plate bonding portion on the inner tank side and the outer tank side of the FRP tubular body, and By detecting strain generated in the FRP tubular body when the magnetic levitation train ascends with strain gauges arranged at the upper and lower parts in the vertical direction, the separation occurrence and the separation length of the adhesive portion are evaluated. A characteristic damage evaluation method for a load support for a magnetically levitated train. And the inner tub of the cold side to store the superconductive coil of a magnetic levitation train, between the outer tub room temperature side to keep the outside of the inner tub in a vacuum state, bonding the metal plate on both ends of F RP made cylindrical body A method of evaluating damage to a load support formed by fastening with a load support having a structure, in the vicinity of the metal plate bonding portion on the inner tank side and the outer tank side of the FRP tubular body, and By detecting strain generated in the FRP tubular body during propulsion of the magnetic levitation train by using strain gauges disposed at the front and rear in the traveling direction, the separation occurrence and separation length of the adhesive portion are evaluated. A method for evaluating damage of a load support for a magnetically levitated train, characterized by: And the inner tub of the cold side to store the superconductive coil of a magnetic levitation train, between the outer tub room temperature side to keep the outside of the inner tub in a vacuum state, bonding the metal plate on both ends of F RP made cylindrical body A method of evaluating damage to a load support formed by fastening with a load support having a structure, in the vicinity of the metal plate bonding portion on the inner tank side and the outer tank side of the FRP tubular body, and The strain generated in the FRP tubular body at the time of excitation of the magnetic levitation train is detected by strain gauges disposed at least in the front and rear portions in the traveling direction, and the separation occurrence and separation length of the adhesive portion are evaluated. A method for evaluating damage of a load support for a magnetically levitated train, characterized by:

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