Casing containment test system and casing containment test method

Abstract

This disclosure relates to the field of aero-engine testing technology, and particularly to a casing containment test system and a casing containment test method. The casing containment test system includes: a test piece comprising a casing and a rotor, the rotor being rotatably disposed within the casing and including a fly-off blade; an explosive device disposed on the fly-off blade for severing the fly-off blade; and a control device that, upon receiving a fly-off command and when the fly-off blade rotates to the detonation phase θ, sends an explosion signal to the explosive device, causing the fly-off blade to break off and fly out, impacting the target impact point of the casing. The detonation phase θ is determined according to a formula, where α is the phase corresponding to the target impact point, and α is the phase the fly-off blade rotates through during the process from the issuance of the explosion signal to impacting the target impact point. Based on this, the test efficiency of the casing containment test can be improved.

Description

Technical Field

[0001] This disclosure relates to the field of aero-engine testing technology, and in particular to a casing containment testing system and a casing containment testing method. Background Technology

[0002] The casing containment test is a mandatory strength test for aero engines stipulated in airworthiness regulations. It is used to verify whether an aero engine meets the airworthiness requirements during the certification process. In actual testing, it is often necessary to impact the blades onto weak points in the casing or other required test locations to assess casing containment. However, existing testing techniques cannot control the impact location of the blades on the casing, affecting testing efficiency. Summary of the Invention

[0003] One of the technical problems that this disclosure aims to solve is to improve the testing efficiency of casing containment tests.

[0004] To address the aforementioned technical problems, the first aspect of this disclosure provides a casing containment testing system, comprising:

[0005] The test piece includes a casing and a rotor, the rotor being rotatably disposed within the casing and including fly-off blades;

[0006] An explosive device, mounted on the fly-off blade, is used to sever the fly-off blade; and

[0007] Upon receiving the detachment command, and when the detachment blade rotates to the detonation phase θ, the control device sends an explosion signal to the explosive device, causing the detachment blade to break off and fly out, impacting the target impact point of the casing. The detonation phase θ is determined according to the formula... It is confirmed that, among them, α represents the phase corresponding to the target impact point, and α is the phase that the flying blade rotates through during the process from the emission of the explosion signal to the impact point of the target.

[0008] In some embodiments, the explosive device includes a detonator and explosives, the detonator detonates the explosives, and a control device sends an explosion signal to the detonator.

[0009] In some embodiments, the control device determines α using the following formula:

[0010] α=T*ω

[0011] Where T is the time required from the explosion signal to the impact of the fly-off blade on the test specimen's casing, and ω is the rotational speed of the fly-off blade when it breaks off and flies out.

[0012] In some embodiments, the casing containment test system includes a speed detection element that detects the speed of the fly-off blade, and a control device determines whether the fly-off blade has reached the fly-off speed ω based on the detection result of the speed detection element.

[0013] In some embodiments, the casing containment test system includes a switch that is signal-connected to a control device that receives a fly-off command when the switch is triggered.

[0014] A second aspect of this disclosure also provides a method for testing the containment of a casing, comprising:

[0015] According to the formula Determine the detonation phase θ, where, α is the phase corresponding to the preset impact point on the casing that the fly-off blade needs to impact, and α is the phase that the fly-off blade rotates through during the process from the emission of the explosion signal to the impact of the preset impact point. The explosion signal is the signal used to detonate the explosive device located on the fly-off blade.

[0016] The test piece is activated, and upon receiving the fly-off command and when the fly-off blade rotates to the detonation phase θ, an explosion signal is sent to the explosive device, causing the fly-off blade to break off and fly out, impacting the target impact point.

[0017] In some embodiments, α is determined using the following formula:

[0018] α=T*ω

[0019] Where T is the time required from the explosion signal to the impact of the fly-off blade on the test specimen's casing, and ω is the rotational speed of the fly-off blade when it breaks off and flies out.

[0020] In some embodiments, T is determined using the following formula:

[0021] T = T1 + T2 + T3 + T4

[0022] Wherein, T1 is the time from the issuance of the explosion signal to the detonation of the detonator in the explosive device, T2 is the time from the detonation of the detonator to the explosion of the explosive in the explosive device, T3 is the time from the explosion of the explosive to the breakage of the fly-off blade, and T4 is the time from the breakage of the fly-off blade to the impact of the fly-off blade on the casing.

[0023] In some embodiments, the flyoff command is issued after the flyoff blades reach the flyoff speed ω.

[0024] In some embodiments, the fly-off command is issued when the switch is triggered.

[0025] The casing containment test system and method provided in this disclosure can control the impact position of the blade on the casing by controlling the timing of blade detachment, thereby achieving directional impact on the target impact point. Therefore, it is beneficial to reduce the number of tests and improve test efficiency.

[0026] Other features and advantages of this disclosure will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the structure of the test piece of the casing containment test system in an embodiment of this disclosure.

[0029] Figure 2 for Figure 1 A magnified schematic diagram of part I.

[0030] Figure 3 This is a schematic diagram illustrating the cooperation between the explosive device and the control device in an embodiment of this disclosure.

[0031] Figure 4 This is a schematic diagram of the detonation phase in an embodiment of this disclosure.

[0032] Figure 5 This is a schematic diagram of the detachment process in an embodiment of this disclosure.

[0033] Figure 6 This is a flowchart of the casing containment test method in an embodiment of this disclosure.

[0034] Explanation of reference numerals in the attached figures:

[0035] 10. Casing containment test system;

[0036] 1. Test piece; 11. Casing; 12. Rotor; 13. Blade; 14. Shaft; 15. Fly-off blade;

[0037] 2. Explosive devices; 21. Detonators; 22. Explosives;

[0038] 3. Control device; 31. Computer;

[0039] A. Target impact point. Detailed Implementation

[0040] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this disclosure or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0041] Techniques, casing containment test methods and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, casing containment test methods and equipment should be considered part of the specification.

[0042] In the description of this disclosure, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings and is only for the convenience of describing this disclosure and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this disclosure; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0043] In the description of this disclosure, it should be understood that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this disclosure.

[0044] Furthermore, the technical features involved in the different embodiments of this disclosure described below can be combined with each other as long as they do not conflict with each other.

[0045] During the operation of an aero-engine, the rotor rotates at high speed. Its blades may break off and fly out due to factors such as high-cycle fatigue, overheating, material defects, and impacts from foreign objects. If the casing cannot contain these detached blades, they may penetrate the casing and strike fuel lines, fuel tanks, control circuits, and the engine compartment, causing structural damage, control failure, fuel leaks, and fires, endangering the safety of the entire aircraft and the lives of passengers, resulting in catastrophic consequences. Therefore, research on the casing containment capacity of aero-engines is essential. Casing containment capacity refers to the casing's ability to contain broken or detached blades.

[0046] The casing containment test is an important means of studying casing containment. It uses methods such as pre-cracking, heating or detonation to cause the blades on the rotor of the test piece to break off and fly out, impacting the casing, thereby testing the containment capacity of the casing, and thus verifying whether the aero engine meets the design requirements for casing containment in airworthiness regulations (such as the airworthiness regulation CCAR33.94 "Blade Containment and Rotor Imbalance Test").

[0047] In some cases, when conducting casing containment tests, there are requirements for the location of the casing impacted by the blade. It is desirable for the blade to impact the target location of the casing (such as the weakest point of the casing or other test requirements). In this way, the casing containment performance can be verified based on the impact results of the blade on the target location (also known as the target impact point).

[0048] In related technologies, it is impossible to precisely control the impact position of the blades. In order to achieve impact on the target position, multiple strikes are usually used until the target is hit, or multiple blades are controlled to fly off at once until the target is hit. However, these test methods are relatively random, with poor accuracy, low efficiency, and high cost. In particular, the method of controlling multiple blades to fly off at once is even more expensive because each blade is very expensive. Furthermore, the randomness of these methods leads to poor repeatability of the casing containment test, making it difficult to reproduce the previous test process in the next test.

[0049] In view of the above, this disclosure provides a casing containment test system and method for controlling the directional impact of blades, so as to improve test efficiency, reduce test costs, and improve test repeatability.

[0050] Figures 1-6 The casing containment test system and casing containment test method of this disclosure are illustrated by way of example.

[0051] See Figure 1-3 The casing containment test system 10 provided in this embodiment includes a test piece 1, an explosive device 2, and a control device 3.

[0052] Test component 1 includes a casing 11 and a rotor 12. The rotor 12 is rotatably disposed within the casing 11 and includes a shaft 14 and multiple (e.g., 18) blades 13 disposed on the shaft 14. Among these multiple blades 13 are fly-out blades 15. The fly-out blades 15 are blades that break off and fly out during the test. As an example, test component 1 is a fan of an aircraft engine, the casing 11 is a fan casing, and the blades 13 are fan blades.

[0053] The explosive device 2 serves as a severing device, and is mounted on the detachment blade 15 to sever the detachment blade 15, causing it to break off and fly out. Specifically, as follows... Figure 1and Figure 2 As shown, the explosive device 2 is located at the root of the fly-off blade 15 and includes a detonator 21 and an explosive 22. The detonator 21 detonates the explosive 22, breaking the fly-off blade 15 off, allowing it to detach from the shaft 14 under centrifugal force and fly towards the housing 11, impacting the housing 11.

[0054] Based on the explosive device 2, the severing device becomes a detonation-type severing device, which uses an explosion to achieve the severing of the fly-off blade 15.

[0055] The action of explosive device 2 is controlled by an explosion signal. Explosive device 2 only detonates upon receiving an explosion signal. The explosion signal is the signal that controls the explosion of explosive device 2. When explosive device 2 includes detonator 21 and explosive 22, the explosion signal is sent to detonator 21, which detonates upon receiving the explosion signal, detonating explosive 22 and severing the fly-off blade 15.

[0056] Control device 3 is used to control the test process. The explosion signal for the aforementioned explosive device 2 is issued by control device 3. See also Figure 6 During the test, test piece 1 is started first. After rotor 12 reaches the flyoff speed ω and runs stably, the staff confirms whether all parameters meet the test requirements. If the test requirements are met, the staff triggers a switch (not shown in the figure) to send a flyoff command to control device 3. After receiving the corresponding flyoff command, control device 3 sends an explosion signal to explosive device 2, controlling explosive device 2 to detonate, causing the flyoff blade 15 to fly off and impact the casing 11. It can be seen that the explosion signal is issued after the flyoff command, while the flyoff command is issued after the flyoff blade 15 reaches the flyoff speed ω and the switch is triggered.

[0057] To control and achieve directional strikes against receiver 11, see [link / reference]. Figure 4 and Figure 6 In some embodiments, the target impact point A is predetermined before the test begins. For example, the weakest part of the casing 11 can be determined as the target impact point A, or other locations required to be tested in the test can be determined as the target impact point A. After the target impact point A is determined, the phase information corresponding to the target impact point A is... Thus, the phase corresponding to the target impact point A can be determined. That is, the phase in which the target impact point A is located.

[0058] See also Figure 6 At the target impact point A and its corresponding phase After determining the detonation phase θ, the next step is to determine the phase of the fly-off blade 15 when the explosion signal is emitted. In other words, the detonation phase θ is the phase information of the fly-off blade 15 corresponding to the emission of the explosion signal, which controls the timing of the explosion signal. Once the detonation phase θ is determined, during the stabilization test, when the fly-off blade 15 rotates to the detonation phase θ, the control device 3 sends an explosion signal to the explosion device 2, severing the fly-off blade 15. The stabilization test refers to the test process after the rotor 12 has stabilized at the fly-off speed ω and the operator has issued the fly-off command.

[0059] It is understandable that how the detonation phase θ is determined directly affects whether the fly-off blade 15 can accurately hit the target impact point A, that is, whether a precise strike on the target impact point A can be achieved.

[0060] See Figure 4 Considering that the fly-off blade 15 is in a high-speed rotation state during the stabilization test, there is a time difference T between the time the explosion signal is issued and the time the fly-off blade 15 impacts the casing 11. During the corresponding time T, the fly-off blade 15 will also rotate through phase α. Therefore, in order to enable the fly-off blade 15 to accurately hit the target impact point A, in the embodiment of this disclosure, the detonation phase θ is determined to be... In other words, the detonation phase θ is based on the formula It is confirmed that, among them, α is the phase corresponding to the target impact point A, and α is the phase that the fly-off blade 15 rotates through during the process from the emission of the explosion signal to the impact point A of the target.

[0061] Based on the determined detonation phase θ, see Figure 6 During the test, the control device 3 can send an explosion signal to the explosion device 2 after receiving the fly-off command and when the fly-off blade 15 rotates to the detonation phase θ, causing the fly-off blade 15 to break off and fly out, impacting the casing 11.

[0062] Since the detonation phase θ is based on the formula The determination process takes into account the angle that the fly-off blade 15 rotates during the process from the emission of the explosion signal to the impact point A of the target, and calculates the lead time. Therefore, the phase of the explosion signal can be accurately located, so that the fly-off blade 15 can accurately impact the target impact point A of the casing 11 after breaking, thus achieving a precise impact on the casing 11. In this way, in the actual test, a precise strike on the target impact point A can be achieved in one go. Therefore, compared with the random impact method of multiple impacts or one-time control of multiple blade breakage in related technologies, the number of tests can be reduced, the test efficiency can be improved, and the test cost can be reduced.

[0063] Furthermore, since the detonation phase θ is determined, the impact point A can be controlled to be hit every time if necessary, thus enhancing the repeatability of the casing containment test.

[0064] As can be seen, the embodiments of this disclosure are based on the phase corresponding to the target impact point A. The detonation phase θ corresponding to the detonation of the explosion signal is determined by the phase α that the flying blade 15 rotates through during the process from the emission of the explosion signal to the impact point A of the impact target. Based on the determined detonation phase θ, the timing of the explosion signal emission is controlled, which can realize a precise, controllable and repeatable casing containment test process for the blade impact position, improve test efficiency and reduce test costs.

[0065] Among them, according to the formula When determining the detonation phase θ, the phase corresponding to the target impact point A is... Since the target impact point A is determined when the explosion signal is issued, the key point in this process is to determine the phase α that the fly-off blade 15 rotates through during the process from the issuance of the explosion signal to the impact point A. Because the fly-off blade 15 has stabilized at the fly-off speed ω before the explosion signal is issued, in some embodiments, α is determined using the following formula:

[0066] α=T*ω

[0067] Wherein, ω is the fly-off speed of the fly-off blade 15, that is, the speed at which the fly-off blade 15 flies off. The fly-off speed ω is determined before the test and is a known quantity. Typically, the fly-off speed ω is less than or equal to 4000 rpm. Before the fly-off command is issued, the rotor 12 generally needs to reach the fly-off speed ω and operate stably at the fly-off speed ω. In some embodiments, the casing containment test system 10 includes a speed detection element (not shown in the figure). The speed detection element detects the speed of the fly-off blade 15. The control device 3 determines whether the fly-off blade 15 has reached the fly-off speed ω based on the detection result of the speed detection element, so that the operator will trigger the switch and issue the fly-off command only after the fly-off blade 15 has reached and stabilized at the fly-off speed ω.

[0068] T is the time required from the issuance of the explosion signal to the impact of the fly-off blade 15 on the casing 11 of the test piece 1. For example... Figure 5As shown, the entire process from the issuance of the explosion signal to the impact of the fly-off blade 5 on the casing is mainly divided into four stages. The first stage is from the issuance of the explosion signal to the detonation of the detonator 21, taking time T1; the second stage is from the detonation of the detonator 21 to the explosion of the explosive 22, taking time T2; the third stage is from the explosion of the explosive 22 to the breakage of the fly-off blade 15, taking time T3; and the fourth stage is from the breakage of the fly-off blade 15 to the impact of the fly-off blade 15 on the casing 11, taking time T4. Therefore, the total time T from the issuance of the explosion signal to the impact of the fly-off blade 5 on the casing can be determined according to the formula T = T1 + T2 + T3 + T4. In this way, the time required for the fly-off blade 15 to impact the casing 11 from the issuance of the explosion signal can be accurately predicted, thereby accurately locating the phase of the explosion signal and controlling the precise directional impact on the casing 11. In some embodiments, T = T1 + T2 + T3 + T4 ≈ 0.6 ms.

[0069] In the foregoing embodiments, the determination of time T and detonation phase θ can all be performed by control device 3, that is, control device 3 determines detonation phase θ and time T. As an example, such as... Figure 3 As shown, the control device 3 is a computer 31. Alternatively, the control device 3 may be a general-purpose processor, a programmable logic controller (PLC), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or any suitable combination thereof for performing the functions described in this disclosure.

[0070] In the foregoing embodiments, the use of explosive fracturing based on the explosive device 2 to achieve the fracture of the fly-off blade 15 has the advantage of better meeting the directional strike requirements of this disclosure. Unlike pre-crack fracturing and heating fracturing, which are non-instantaneous fracturing methods where the timing is difficult to control, explosive fracturing is controllable and is an instantaneous fracturing process. Therefore, using explosive fracturing to achieve the fracture of the fly-off blade 15 allows for convenient control of the timing of the explosion signal to initiate the fracturing process, thereby controlling the impact position of the fly-off blade 15 and achieving a precise strike.

[0071] Next, combine Figure 6 The casing containment test process of this disclosure is further explained.

[0072] First, in accordance with the test requirements, test preparation work was carried out, including determining the target impact point A and its corresponding phase. And determine the detonation phase θ, where the detonation phase θ is based on the phase corresponding to the determined target impact point A. The time T required from the issuance of the explosion signal to the impact of the fly-off blade 15 on the casing 11 of the test piece 1, and the fly-off speed ω of the fly-off blade 15 are used to determine the time, i.e.

[0073] Then, test piece 1 is started, and the rotor 12 of test piece 1 begins to rotate. After the rotor 12 reaches the fly-off speed ω and runs stably for a period of time, the staff confirms whether the parameters meet the test requirements. When the parameters meet the test requirements, the switch is triggered and a fly-off command is issued.

[0074] After receiving the detachment command, the control device 3 determines the phase of the detachment blade 15. When the detachment blade 15 reaches the detonation phase θ, the control device 3 sends an explosion signal to the detonator 21 of the explosive device 2.

[0075] After receiving the explosion signal, the detonator 21 detonates the explosive 22, causing the fly-off blade 15 to break off and fly out according to the preset program, accurately impacting the target impact point A of the casing 11.

[0076] As can be seen, this embodiment can accurately predict the time required for the fly-off blade 15 to travel from the explosion signal to the impact casing 11, calculate the lead time, and accurately locate the phase of the explosion signal. This allows for precise control of the impact position of the fly-off blade 15 on the casing 11, thus accurately achieving a directional impact on the casing 11.

[0077] Multiple tests and adjustments have shown that the total time error during the test of this embodiment is ΔT = ΔT1 + ΔT2 + ΔT3 + ΔT4 < 0.2 ms, and the speed measurement error is... Therefore, when the flyaway speed ω ≤ 4000 rpm and T = T1 + T2 + T3 + T4 ≈ 0.6 ms, the phase error of the corresponding target impact point A can be obtained as follows: That is, the phase error of the target impact point A. The tolerance is ±2.5°, which meets the requirement for accurate blade impact at a specific location on the casing during the casing containment test. This indicates that the corresponding casing containment test can achieve precise impact of the blades of test piece 1 on the casing at speeds below 4000 rpm, and it is repeatable. It can be understood that rpm and rps are units of rotational speed, representing revolutions per minute and revolutions per second, respectively.

[0078] In summary, the embodiments of this disclosure, by accurately locating the phase of the explosion signal, can achieve a high-precision and repeatable directional impact casing containment test process. This supplements and improves the test techniques and design concepts for blade fly-off and casing containment tests, fully meeting the airworthiness requirements of CCAR33.94 for casing containment tests while improving test efficiency and reducing test costs. The casing containment test system 10 and casing containment test method provided in these embodiments can be applied to the performance evaluation and airworthiness certification tests of aero-engine fans.

[0079] The above description is merely an exemplary embodiment of this disclosure and is not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A casing containment test system (10), characterized in that, include: The test piece (1) includes a casing (11) and a rotor (12), the rotor (12) being rotatably disposed within the casing (11) and including fly-off blades (15). An explosive device (2) is disposed on the fly-off blade (15) for blasting off the fly-off blade (15). and After receiving the detachment command, the control device (3) rotates the detachment blade (15) to the detonation phase. An explosion signal is sent to the explosive device (2), causing the fly-off blade (15) to break off and fly out, impacting the target impact point (A) of the casing (11). The detonation phase... According to the formula It is confirmed that, among them, The phase corresponding to the target impact point (A) The phase through which the fly-off blade (15) rotates from the point of origin of the explosion signal to the point of impact of the target (A).

2. The casing containment test system (10) according to claim 1, characterized in that, The explosive device (2) includes a detonator (21) and explosives (22), the detonator (21) detonates the explosives (22), and the control device (3) sends the explosion signal to the detonator (21).

3. The casing containment test system (10) according to claim 1 or 2, characterized in that, The control device (3) is determined using the following formula. : in, The time required from the emission of the explosion signal to the impact of the fly-off blade (15) on the casing (11) of the test piece (1), The rotational speed of the fly-off blade (15) when it breaks off and flies out.

4. The casing containment test system (10) according to claim 3, characterized in that, The casing containment test system (10) includes a rotation speed detection device that detects the rotation speed of the fly-off blade (15). The control device (3) determines, based on the detection result of the rotation speed detection device, whether the fly-off blade (15) has reached the rotation speed at which the fly-off blade (15) breaks off and flies out. .

5. The casing containment test system (10) according to claim 1, characterized in that, The casing containment test system (10) includes a switch that is signal-connected to the control device (3), which receives the fly-out command when the switch is triggered.

6. A casing containment test method based on the casing containment test system (10) as described in any one of claims 1-5, characterized in that, include: According to the formula Determine the detonation phase ,in, The phase corresponding to the preset impact point on the casing (11) that the fly-off blade (15) needs to impact. The phase through which the fly-off blade (15) rotates from the emission of the explosion signal to the impact of the preset strike point, wherein the explosion signal is the signal used to detonate the explosive device (2) located on the fly-off blade (15); The test piece (1) is activated, and upon receiving the fly-off command, the fly-off blade (15) rotates to the detonation phase. At that time, an explosion signal is sent to the explosive device (2), causing the flying blade (15) to break off and fly out, impacting the target impact point (A).

7. The casing containment test method according to claim 6, characterized in that, The following formula is used to determine it: in, The time required from the emission of the explosion signal to the impact of the fly-off blade (15) on the casing (11) of the test piece (1), The rotational speed of the fly-off blade (15) when it breaks off and flies out.

8. The casing containment test method according to claim 7, characterized in that, The following formula (3) is used to determine: in, The time from the issuance of the explosion signal to the detonation of the detonator (21) of the explosive device (2), The time from the explosion of the detonator (21) to the explosion of the explosive (22) in the explosive device (2), The time from the explosion of the explosive (22) to the breakage of the fly-off blade (15) The time from the breakage of the fly-off blade (15) to the impact of the fly-off blade (15) on the casing (11).

9. The casing containment test method according to claim 7, characterized in that, The fly-off command is given when the fly-off blade (15) reaches the rotational speed at which the fly-off blade (15) breaks off and flies out. It was sent later.

10. The casing containment test method according to claim 6, characterized in that, The fly-off command is issued when the switch is triggered.

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