Patent Description:
Composite materials may be applied to components constituting an aircraft. For example, in the main wings, hat-type stringer composite materials have been commonly used as reinforcement materials.

Such composite materials require nondestructive inspection such as ultrasonic testing, because internal flaws such as porosity may occur after curing.

However, the inner circumferential surface of a hat-type stringer as a test object has a substantially rectangular shape closed in a transverse section. Thus, when flaw detection of inside corners is required, access from outside of the stringer is difficult. For this reason, there is a problem in flaw detection of the inside corners.

As an ultrasonic testing method targeting such corners, there are methods disclosed in <CIT> and <CIT>, for example.

<CIT> and <CIT> are examples of the related art.

Typical ultrasonic testing employs a water immersion method in which a test object is submerged in water and inspected. In this method, however, air bubbles that degenerate reliability of ultrasonic testing are likely to be attached to the surface of a test object, which requires removal operation of such air bubbles from the surface of the test object. Further, before submerging a test object, transportation or positioning operation of the test object is required.

In this regard, the method disclosed in <CIT> is an ultrasonic testing method using a gel pad, and this is a pulse-echo method to supply a small amount of water from a sponge when a gap occurs between a test object and the gel pad. This enables flaw detection without submerging a test object in water.

However, for a centering device provided with a probe, it is not possible to change the transverse sectional shape thereof. Thus, when there is a change in the transverse sectional shape of a test object, the centering device cannot follow such a change. Accordingly, the ultrasonic testing device disclosed in <CIT> is only applicable to test objects having a constant transverse sectional shape. Further, since gel pads are consumables, a problem remains also in terms of costs for secondary materials.

On the other hand, the ultrasonic testing device disclosed in <CIT> is configured to follow a change in the cross-sectional shape of a test object by employing an expansion/contraction mechanism.

However, in the ultrasonic testing method using this device disclosed in <CIT>, a test object is required to be submerged in water, which causes the problem described above.

<CIT> an ultrasonic testing device which represents the closest prior art.

The present disclosure has been made in view of such circumstances and intends to provide an ultrasonic testing device and a testing method that can realize a modified immersion (bubbler) method in which a test object is not required to be submerged in water, and that can perform flaw detection in a state where a shoe is suitably pressed against a corner of a test object even when there is a change in the transverse sectional shape of the inner circumferential surface of the test object.

This object is solved by an ultrasonic testing device with the features of claim <NUM> and a testing method with the features of claim <NUM>. Preferred embodiments follow from the other claims.

To solve the problems described above, an ultrasonic testing device and a testing method of the present disclosure employ the following solutions.

An ultrasonic testing device according to one aspect of the present disclosure performs flaw detection on a test object having an inner circumferential surface of a substantially rectangular shape closed in a transverse section. The ultrasonic testing device includes: a shoe configured to be in contact with one corner of the inner circumferential surface of the test object; an ultrasonic array configured to be fixed to the shoe to define, together with the shoe and the one corner, a medium space in which a contact medium used for propagating an ultrasonic wave is enclosed, and configured to transmit an ultrasonic wave to the one corner and receive a reflected ultrasonic wave; and a forcing unit configured to be in contact with a diagonal corner of the one corner and push the shoe against the one corner.

Further, a testing method of a test object according to one aspect of the present disclosure uses an ultrasonic testing device including a shoe configured to be in contact with one corner of an inner circumferential surface of the test object having the inner circumferential surface of a substantially rectangular shape closed in a transverse section, an ultrasonic array configured to be fixed to the shoe to define, together with the shoe and the one corner, a medium space in which a contact medium used for propagating an ultrasonic wave is enclosed, and configured to transmit an ultrasonic wave to the one corner and receive an ultrasonic wave reflected by the one corner, and a forcing unit configured to be in contact with a diagonal corner of the one corner and push the shoe against the one corner. The testing method includes a step of performing flaw detection in a state where the shoe is in contact with the one corner of the test object and a contact medium is enclosed in the medium space.

According to the present disclosure, it is possible to realize a modified immersion (bubbler) method in which a test object is not required to be submerged in water and it is possible to perform flaw detection with a shoe being suitably pressed against a corner of a test object even when there is a change in the transverse sectional shape of the inner circumferential surface of the test object.

An ultrasonic testing device and a testing method according to one embodiment of the present disclosure will be described below with reference to the drawings.

As illustrated in <FIG> and <FIG>, an ultrasonic testing device <NUM> performs flaw detection on an inner circumferential surface <NUM> of a stringer <NUM> as a test object.

The stringer <NUM> is a member applied to a reinforcement material of main wings of an aircraft, for example, and is made of a composite material such as a fiber-reinforced resin. The stringer <NUM> is of a so-called hat type and has the inner circumferential surface <NUM> of a substantially rectangular shape closed in the transverse section.

The substantially rectangular inner circumferential surface <NUM> has corners 82a, 82b, 82c, and 82d. The corners 82a, 82b, 82c, and 82d are each shaped in a circular arc having a predetermined radius.

As illustrated in <FIG>, the ultrasonic testing device <NUM> has a shoe <NUM>, an ultrasonic array <NUM>, and a forcing unit <NUM>.

The shoe <NUM> is a resin member having a substantially L-shape in side view. As the resin, glycol-modified polyethylene terephthalate (PETG) is illustrated as an example.

In <FIG>, the lower side of the shoe <NUM> serves as a grounding part <NUM>. A grounding surface 14a formed on the under surface of the grounding part <NUM> contacts with a base surface <NUM> of the stringer <NUM>. The base surface <NUM> is a portion of the inner circumferential surface <NUM> connected between the corner 82a and the corner 82b.

A recess 14b is formed in the grounding surface 14a.

The recess 14b is an inverse U-shape portion recessed so as to be spaced apart from the base surface <NUM>. Accordingly, the grounding surface 14a can be configured so as not to come into contact with the base surface <NUM> in the recess 14b. Note that the shape of the recess 14b is not limited to the illustrated shape.

The grounding part <NUM> is connected to an erected part <NUM> via a connecting part <NUM>.

The erected part <NUM> is a perpendicularly extending portion of the shoe <NUM>.

The connecting part <NUM> connects the grounding part <NUM> to the erected part <NUM> and is in contact with the corner (one corner) 82a. The connecting part <NUM> has the external shape (outer surface) formed in a circular arc so as to fit to the shape of the corner 82a.

As illustrated in <FIG>, the shoe <NUM> has two inner walls <NUM>.

Each inner wall <NUM> is a wall-shaped portion erected upward in the perpendicular direction from the grounding part <NUM> and connected to the erected part <NUM>.

A gap G is provided between the inner walls <NUM>. As illustrated in <FIG>, the gap G communicates with an opening <NUM> formed in the connecting part <NUM>. Thus, the gap G communicates with the outside of the shoe <NUM> via the opening <NUM>. In this state, the opening <NUM> is formed to face the corner 82a. The ultrasonic array <NUM> is fitted into the gap G configured in such a way, as illustrated in <FIG>, <FIG>, and the like.

As illustrated in <FIG>, a plurality of (two in <FIG>) array attachment holes 11a are formed in one of the inner walls <NUM>. Each array attachment hole 11a is a through hole in which a screw for fixing the ultrasonic array <NUM> is inserted. The array attachment hole 11a is a slot so that the position of the ultrasonic array <NUM> can be adjusted.

Outer walls <NUM> are wall-shaped portions erected upward perpendicularly from the grounding part <NUM> and connected to the erected part <NUM>. One outer wall <NUM> is provided on each of both the outsides of the inner walls <NUM>.

A counterbored hole 12a is formed in the outer wall <NUM>. The counterbored hole 12a is a stepped through hole through which a shaft of a cap bolt <NUM> described later is inserted and with which a head of the cap bolt <NUM> comes into contact.

As illustrated in <FIG> and <FIG>, the ultrasonic array <NUM> is a member with an element arrangement surface <NUM> formed.

As illustrated in <FIG>, the element arrangement surface <NUM> is a circular arc-shaped curved surface facing the corner 82a of the stringer <NUM>.

Many elements are arranged on the element arrangement surface <NUM>. These elements transmit ultrasonic waves to the corner 82a and receive reflected ultrasonic waves. This enables flaw detection inside the stringer <NUM>.

The ultrasonic array <NUM> is connected to a cable <NUM> and configured to be able to communicate with a control device or the like (not illustrated).

As illustrated in <FIG> and <FIG>, the ultrasonic array <NUM> is arranged in the gap G formed between the inner walls <NUM>. In this state, the side surface <NUM> of the ultrasonic array <NUM> is covered with the inner wall <NUM>.

A screw hole 21a is formed in the side surface <NUM> of the ultrasonic array <NUM>. A screw is inserted in an array attachment hole 11a formed in the inner wall <NUM> and is screwed with the screw hole 21a. Thereby, the ultrasonic array <NUM> will be attached to the inner wall <NUM> while interposed between the two inner walls <NUM>.

In this state, as illustrated in <FIG>, the ultrasonic array <NUM> is fixed to a position where the radius center of the element arrangement surface <NUM> matches the radius center of the corner 82a. Note that, since the position of the ultrasonic array <NUM> is adjustable, it is possible to match the radius center to the corner 82a having various radii even with a constant curvature radius of the element arrangement surface <NUM>.

In the shoe <NUM> to which the ultrasonic array <NUM> is attached as illustrated in <FIG> and <FIG>, the connecting part <NUM> as illustrated in <FIG> is brought into contact with the corner 82a of the inner circumferential surface <NUM>, so that the opening <NUM> formed in the connecting part <NUM> is closed by the corner 82a. This defines a space (medium space Sm) closed by the inner walls <NUM>, the element arrangement surface <NUM> of the ultrasonic array <NUM>, and the surface of the corner <NUM>.

The medium space Sm is supplied with a contact medium via a joint <NUM>. The supplied contact medium is then enclosed in the closed medium space Sm, which can configure the pulse-echo ultrasonic testing device <NUM> in which modified immersion (bubbler) is realized by the medium space Sm.

Herein, the contact medium is a medium that facilitates propagation of ultrasonic waves and may be a liquid such as water or an oil as an example.

Note that, as illustrated in <FIG>, it is possible to improve liquid tightness by setting the height size of the inner wall <NUM> so that the inner wall <NUM> has a height exceeding the side surface <NUM> of the ultrasonic array <NUM> with the ultrasonic array <NUM> being attached.

Further, as illustrated in <FIG>, the width size of the opening <NUM> is matched to the width size of the ultrasonic array <NUM>, and this reduces a risk of leakage of a large amount of contact medium enclosed in the medium space Sm out of the opening <NUM> due to an unnecessarily widened opening <NUM>.

As illustrated in <FIG> and <FIG>, the forcing unit <NUM> is a mechanism configured to be in contact with the corner (diagonal corner) 82c and push, against the corner 82a, the shoe <NUM> to which the ultrasonic array <NUM> is attached.

As illustrated in <FIG>, the forcing unit <NUM> has arms <NUM>, a diagonal housing <NUM>, and springs (first forcing member) <NUM>.

The arm <NUM> is a substantially L-shape member provided on each of the outer walls <NUM> of the shoe <NUM>. The substantially L-shape arm <NUM> can avoid interference with the cable <NUM> connected to the ultrasonic array <NUM>.

As illustrated in <FIG>, a screw hole 31a is formed at the end of the lower side of the arm <NUM>. The cap bolt <NUM> is inserted in the counterbored hole 12a formed in the outer wall <NUM> and is screwed therewith. Accordingly, the arm <NUM> is attached to the outer wall <NUM> in a pivotable manner.

A screw hole 31b is formed in the end face of the side edge part of the arm <NUM>. The screw hole 31b is a hole with which a cap bolt <NUM> described later is screwed.

As illustrated in <FIG>, the diagonal housing <NUM> is connected to the two arms <NUM> via the springs (first forcing member) <NUM> and the cap bolt <NUM>.

The diagonal housing <NUM> is in contact with the corner 82c.

The diagonal housing <NUM> is formed so as to fit the shapes of the corner 82c and the inner circumferential surface <NUM> near the corner 82c. In <FIG>, the diagonal housing <NUM> is a columnar member having a substantially triangular transverse section.

As illustrated in <FIG> and <FIG>, counterbored holes 32a are formed in the diagonal housing <NUM>. Each counterbored hole 32a is a stepped through hole through which the shaft of the cap bolt <NUM> is inserted and with which the head of the cap bolt <NUM> comes into contact.

The diagonal housing <NUM> is fixed to the arms <NUM> by the cap bolts <NUM> inserted from the diagonal housing <NUM> toward the arm <NUM>.

In this state, the springs <NUM> are interposed between the diagonal housing <NUM> and the arms <NUM>, the shafts of the cap bolts <NUM> are inserted in the springs <NUM>, and thereby the diagonal housing <NUM> is urged in a direction away from the arms <NUM>. Accordingly, the shoe <NUM> is pushed against the corner 82a by elastic force exerted by the springs <NUM>.

Note that, in the counterbored hole 32a, the inner diameter of a portion in which the shaft of the cap bolt <NUM> is inserted is larger than the outer diameter of the shaft of the cap bolt <NUM>. This allows the diagonal housing <NUM> to move smoothly.

As illustrated in <FIG>, in the forcing unit <NUM>, springs (second forcing member) <NUM> may be interposed between the lower side of the arm <NUM> and the grounding part <NUM> of the shoe <NUM>. Accordingly, the grounding part <NUM> is urged in a direction away from the arms <NUM>, and the grounding part <NUM> (the grounding surface 14a) can be pushed against the base surface <NUM> by elastic force exerted by the springs <NUM>.

The ultrasonic testing device <NUM> configured as described above is used as follows.

As illustrated in <FIG> and <FIG>, the ultrasonic testing device <NUM> is accommodated in the internal space of the stringer <NUM>. In this state, the connecting part <NUM> in which the opening <NUM> is formed is pushed against the corner 82a of the inner circumferential surface <NUM> by the forcing unit <NUM>, and the grounding surface 14a is pushed against the base surface <NUM> by the springs <NUM>.

Herein, a contact medium (for example, water) is supplied to the medium space Sm, and the contact medium is enclosed in the medium space Sm. This facilitates propagation of ultrasonic waves between the ultrasonic array <NUM> and the corner 82a.

In such a state, the ultrasonic testing device <NUM> is moved in the longitudinal direction of the stringer <NUM>, so that an internal flaw of the stringer <NUM> near the corner 82a can be inspected over an extent of the longitudinal direction of the stringer <NUM>.

Note that a rotary encoder <NUM> is provided on the ultrasonic testing device <NUM>, and the position of the ultrasonic testing device <NUM> in the longitudinal direction can be acquired and recognized.

According to the present embodiment, the following advantageous effects are achieved.

The embodiment includes: the shoe <NUM> configured to be in contact with the corner 82a; an ultrasonic array <NUM> configured to be fixed to the shoe <NUM> to define, together with the shoe <NUM> and the corner 82a, the medium space Sm in which a contact medium used for propagating an ultrasonic wave is enclosed, and configured to transmit an ultrasonic wave to the corner 82a and receive an ultrasonic wave reflected by the corner 82a; and a forcing unit <NUM> configured to be in contact with the corner 82c and push the shoe <NUM> against the corner 82a. Thus, in a modified immersion (bubbler) method using a contact medium enclosed in the medium space Sm, it is possible to perform flaw detection while pressing the shoe <NUM> against the corner 82a by the forcing unit <NUM>. Therefore, flaw detection can be performed with the shoe <NUM> being suitably pressed against the corner 82a even when there is a change in the transverse sectional shape of the inner circumferential surface <NUM> of the stringer <NUM>.

Further, since the modified immersion (bubbler) method is employed, it is not required to submerge the stringer <NUM> in a water tank, and this eliminates the need for removal operation of air bubbles attached to the surface of the stringer <NUM> or transportation and positioning operation of the stringer <NUM>.

Further, in the modified immersion (bubbler) method using a contact medium enclosed in the medium space Sm, consumables are not necessary, unlike in the case of using gel pads or the like, for example. Therefore, cost for secondary materials can be reduced.

Further, since the ultrasonic array <NUM> is provided on the shoe <NUM> in a movable manner, the radius center of the element arrangement surface <NUM> can be matched to the radius center of the corner 82a even when there is a change in the radius of the corner 82a, and the ultrasonic wave can be suitably reflected.

Further, the arm <NUM> is connected to the shoe <NUM> in a pivotable manner, and therefore, even when there is a change in the positional relationship between the corner 82a and the corner 82c, such a change can be absorbed by pivot movement of the arm <NUM>.

Further, the recess 14b recessed in a direction away from the base surface <NUM> is formed in the grounding surface 14a, and therefore, even when a protrusion, a bump, or the like is formed on the base surface <NUM>, it is possible to move the ultrasonic testing device <NUM> while avoiding such a protrusion, a bump, or the like.

Further, the spring <NUM> is provided to apply force to the arm <NUM> and the grounding part <NUM> in directions in which the arm <NUM> and the grounding part <NUM> move away from each other, and therefore flaw detection can be performed with the grounding surface 14a formed on the grounding part <NUM> being suitably pressed against the base surface <NUM> of the stringer <NUM>.

The ultrasonic testing device and the testing method according to one embodiment as described above are recognized as follows, for example.

The ultrasonic testing device (<NUM>) according to one aspect of the present disclosure performs flaw detection on a test object (<NUM>) having an inner circumferential surface (<NUM>) of a substantially rectangular shape closed in a transverse section. The ultrasonic testing device includes: a shoe (<NUM>) configured to be in contact with one corner (82a) of the inner circumferential surface of the test object; an ultrasonic array (<NUM>) configured to be fixed to the shoe to define, together with the shoe and the one corner, a medium space (Sm) in which a contact medium used for propagating an ultrasonic wave is enclosed, and configured to transmit an ultrasonic wave to the one corner and receive a reflected ultrasonic wave; and a forcing unit (<NUM>) configured to be in contact with a diagonal corner (82c) to the one corner and push the shoe against the one corner.

According to the ultrasonic testing device of the present aspect, the ultrasonic testing device includes: the shoe configured to be in contact with one corner of the inner circumferential surface of the test object; the ultrasonic array configured to be fixed to the shoe to define, together with the shoe and the one corner, the medium space in which a contact medium used for propagating an ultrasonic wave is enclosed, and configured to transmit an ultrasonic wave to the one corner and receive a reflected ultrasonic wave; and the forcing unit configured to be in contact with the diagonal corner to the one corner and push the shoe against the one corner. Thus, in a modified immersion (bubbler) method using a contact medium enclosed in the medium space, it is possible to perform flaw detection while pressing the shoe against the corner of the test object by the forcing unit. Therefore, flaw detection can be performed with the shoe being suitably pressed against the corner of the test object even when there is a change in the transverse sectional shape of the inner circumferential surface of the test object.

Further, since the modified immersion (bubbler) method is employed, it is not required to submerge the test object in a water tank, and this eliminates the need for removal operation of air bubbles attached to the surface of the test object or transportation and positioning operation of the test object.

Further, in the modified immersion (bubbler) method using a contact medium enclosed in the medium space, consumables are not necessary, unlike in the case of using gel pads or the like, for example. Therefore, cost for secondary materials can be reduced.

Further, in the ultrasonic testing device according to one aspect of the present disclosure, the ultrasonic array is provided on the shoe in a movable manner.

In the ultrasonic testing device according to the present aspect, since the ultrasonic array is provided on the shoe in a movable manner, ultrasonic waves can be suitably reflected even when there is a change in the radius of the one corner.

Further, in the ultrasonic testing device according to one aspect of the present disclosure, the shoe has a grounding part (<NUM>) including a grounding surface (14a) that is in contact with a base surface (<NUM>) of the test object connected to the one corner, two walls (<NUM>) covering both side surfaces (<NUM>) of the ultrasonic array and defining the medium space, and an opening (<NUM>) facing the one corner and communicating with the medium space between the two walls.

In the ultrasonic testing device according to the present aspect, the shoe has the grounding part including the grounding surface that is in contact with the base surface of the test object connected to the one corner, the two walls covering both side surfaces of the ultrasonic array and defining the medium space, and the opening facing the one corner and communicating with the medium space between the two walls. Thus, the test object can be stably grounded by the grounding surface, and the medium space can be defined in a simple manner by the two walls, the one corner, and the ultrasonic array.

Further, in the ultrasonic testing device according to one aspect of the present disclosure, the forcing unit has an arm (<NUM>) connected to the shoe in a pivotable manner, a diagonal housing (<NUM>) configured to be in contact with the diagonal corner, and a first forcing member (<NUM>) configured to apply force to the arm and the diagonal housing in directions in which the arm and the diagonal housing move away from each other.

In the ultrasonic testing device according to the present aspect, the forcing unit has the arm connected to the shoe in a pivotable manner, the diagonal housing configured to be in contact with the diagonal corner, and the first forcing member configured to apply force to the arm and the diagonal housing in directions in which the arm and the diagonal housing move away from each other. Thus, the shoe can be pressed against the corner of the test object by the first forcing member. Further, the arm is connected to the shoe in a pivotable manner, and therefore, even when there is a change in the positional relationship between the one corner and the diagonal corner, such a change can be absorbed by pivot movement of the arm.

Further, in the ultrasonic testing device according to one aspect of the present disclosure, a recess (14b) recessed in a direction away from the base surface is formed in the grounding surface.

In the ultrasonic testing device according to the present aspect, since the recess recessed in the direction away from the base surface is formed in the grounding surface, even when a protrusion, a bump, or the like are formed on the base surface, it is possible to move the ultrasonic testing device while avoiding such a protrusion, a bump, or the like.

Further, the ultrasonic testing device according to one aspect of the present disclosure includes a second forcing member (<NUM>) configured to apply force to the arm and the grounding part in directions in which the arm and the grounding part move away from each other.

In the ultrasonic testing device according to the present aspect, since the second forcing member is provided to apply force to the arm and the grounding part in the directions in which the arm and the grounding part move away from each other, flaw detection can be performed in a state where the grounding surface formed on the grounding part is suitably pressed against the base surface of the test object.

Claim 1:
An ultrasonic testing device (<NUM>) for performing flaw detection on a test object (<NUM>), preferably a hat-type stringer, having an inner circumferential surface (<NUM>) of a substantially rectangular shape closed in a transverse section and one corner (82a) of the inner circumferential surface (<NUM>), the ultrasonic testing device (<NUM>) comprising:
a shoe (<NUM>) configured to be in contact with the one corner (82a) of the inner circumferential surface (<NUM>) of the test object (<NUM>) when the ultrasonic testing device (<NUM>) and the test object (<NUM>) are combined in use,
an ultrasonic array (<NUM>) configured to be fixed to the shoe (<NUM>) and configured to transmit an ultrasonic wave to the one corner (82a) and to receive a reflected ultrasonic wave; and
a forcing unit (<NUM>) configured to be in contact with a diagonal corner (82c) of the one corner (82a) and to push the shoe (<NUM>) against the one corner (82a) when the ultrasonic testing device (<NUM>) and the test object (<NUM>) are combined in use,
characterized in that
the ultrasonic array is configured to define, together with the shoe (<NUM>) and the one corner (82a), a medium space (Sm) which is closed and in which a contact medium used for propagating an ultrasonic wave is to be enclosed when the ultrasonic testing device (<NUM>) and the test object (<NUM>) are combined in use.