KR102585465B1 - Non-explosive Underwater Impact Test Devices and Methods Using Metal Foil Electrical Evaporation - Google Patents

Abstract

The present invention relates to an underwater impact test device and method using electroevaporation of metal foil. Existing underwater shock test devices and methods used air guns to generate shock waves, but they have the disadvantage of being concentrated at low frequencies compared to explosives, so multiple metal foils were attached to the hull to generate underwater shock waves with a wide frequency range through electroevaporation. want to form.
In addition, the metal foil attached to the hull can form an array using cloth or film, and the array can change the thickness and shape of the metal foil and arrange various types of metal, and the blasting time of each metal foil can be adjusted. It is characterized in that it is controlled to form a plane wave.

Description

Non-explosive Underwater Impact Test Devices and Methods Using Metal Foil Electrical Evaporation}

The present invention relates to an underwater impact testing device and method, and more specifically, to an underwater impact testing device and method for applying shock waves to a hull floating in the water to test the survivability of the hull.

In naval ships, shock resistance performance is essential for maintaining combat performance and improving survivability. It is known that most cases of a ship being unable to fight when a torpedo or mine explodes at a long distance are due to impact damage to the main onboard equipment rather than impact damage to the ship's hull. The impact resistance performance of ships in the event of an underwater explosion at such a long distance is being actively studied through simulation. However, even in the United States and Europe, shock resistance performance cannot be evaluated solely through these analysis results, so ships built using high-performance explosives are tested on actual seas. Impact resistance performance is being verified through . However, live ship impact tests using actual explosives not only cost a lot of money and take a long time, but also have a negative impact on marine pollution and the ecosystem, and threaten the safety of ships passing through nearby waters and test personnel.

To this end, the Royal Navy is conducting underwater shock tests on ships in ports using an air gun system that generates artificial seismic waves for seabed resource exploration. Air guns generate shock waves underwater by quickly releasing compressed air in an internal pressure chamber, and can generate enough shock to enable impact testing of ships. However, it is difficult to create plane waves suitable for underwater shock tests, and air guns are Related equipment such as high-pressure compressors for operation are very expensive, and compared to explosives, air guns only have a frequency of several tens of Hz, so shock tests using air guns are similar to shock waves caused by underwater explosions in the low frequency range, but in the higher frequency range, There is a problem of lack of similarity.

Therefore, the present invention was created to solve the problems of the prior art as described above. The present invention attaches a metal foil to the surface of the hull and evaporates it with a high-pressure electric pulse to form a shock wave in the water to perform a conventional air gun impact test. The goal is to improve the underwater impact test device to reach the high frequency range, which is lacking in the device.

The present invention includes a metal foil attached to the surface of a hull and generating shock waves through electrical evaporation, a signal generator connected to the metal foil with an electric wire and sending an electric signal, and the metal foil is generated at time intervals by the signal generator. It is characterized by electrical evaporation and forming a plane wave at time intervals.

In addition, a discharge protection film is disposed between the metal foil and the hull.

In addition, the plurality of metal foils are arranged at regular intervals to form an array that generates high-frequency shock waves.

In addition, it is characterized by frequency range control through change in the shape of the metal foil.

In addition, it is characterized by frequency range control through voltage changes of the metal foil.

Additionally, the metal foil is characterized by frequency domain control using different metal materials.

In addition, the metal foil is electrically evaporated at time intervals by the signal generator and forms a plane wave at time intervals.

In addition, in the underwater shock test method using metal foil electroevaporation using an underwater shock test device using metal foil electroevaporation, the metal foil array preparation step, the array attachment step on the hull surface, and the metal foil are separated from the signal generator. It is characterized by comprising an explosion step of receiving an electric signal, and a measurement step of placing a sensor on the hull and measuring the shock wave generated by the metal foil.

Additionally, the preparation step is characterized in that the plurality of metal foils form an array on a film or fabric.

In addition, the explosion step is characterized in that the signal generator adjusts the blasting time of each metal foil so that a plane wave reaches the hull.

According to the present invention, a plurality of metal foils can generate high-frequency shock waves in the hull through electrical evaporation.

Additionally, the frequency range of metal foil can be adjusted by attaching foils with different metals, thicknesses, and shapes.

Additionally, tests similar to explosives can be conducted by adjusting the blasting sequence of the attached metal foil.

1 is a configuration diagram of the present invention
Figure 2 is an enlarged view of the present invention
Figure 3 is an implementation diagram of the present invention
Figure 4 is a second embodiment of the present invention
Figure 5 is a third embodiment of the present invention
Figure 6 is a block diagram of the present invention
Figure 7 is a graph of energy change through voltage change
Figure 8 is an example of hull attachment of the present invention

The present invention generates underwater shock waves by utilizing the electric evaporation of a plurality of metal foils, thereby generating underwater shock waves that are closer to a high frequency than when generated using an air gun, which is a conventional test method.

When an instantaneous high-voltage electric pulse is applied to a metal, the temperature of the metal increases, which increases the resistance of the metal. Due to this resistance, the temperature of the metal rises further and resistance increases, making it difficult for current to flow, so electrical energy is accumulated in the metal as heat energy. As a result, the metal undergoes a phase change and changes into the form of plasma. A large amount of current flows through the plasma, and the metal's reaction energy spreads out accompanied by strong light and explosions. Because the metal changes state from a solid to a high-temperature gas, the metal expands in volume, pushes out the surrounding medium, and generates a strong shock wave.

Hereinafter, the non-explosive underwater impact test apparatus and method using metal foil electroevaporation for the present invention having the above-described configuration will be described in detail with reference to the attached drawings.

[1] Overall composition and operating principle

First, Figure 1 is an overall configuration diagram of the present invention. Referring to FIG. 1, a single or multiple metal foils 100 are attached to the submerged surface of the hull 300, and each metal foil 100 is connected to the signal generator 400 with an electric wire. At this time, the metal foil 100 is formed as a thin film and is attached to correspond to the surface of the hull 300. The high-frequency shock wave generated by electroevaporation of the metal foil is transmitted directly to the hull 300 to which the metal foil 100 is evaporated and attached, and a shock wave in a high frequency range similar to an explosive can be applied to the hull 300.

Although not shown, the present invention includes a capacitor that stores electrical energy and can quickly transmit the electrical energy as an electrical pulse, and transmits the high-voltage electrical pulse to the metal foil 100 to form a shock wave through metal evaporation.

Figure 2 is an enlarged view of the present invention. Referring to FIG. 2, a plurality of metal foils 100 are attached to the bottom of the hull 300 floating on the water to form shock waves by electric pulses. The measuring unit 310 within the hull 300 measures the shock wave generated by electroevaporation of the metal foil 100.

At this time, a discharge protection film 110 is disposed between the metal foil 100 and the hull 300 to protect against electric discharge due to blasting of the metal foil 100. The measuring unit 310 includes an acceleration sensor and a pressure sensor.

Figure 3 is a diagram showing the configuration of an array of metal foils. Referring to FIG. 3, the metal foil 100 forms an array 200 on a cloth or film at regular intervals, making it easy to attach to the surface of the ship. An electric wire is connected to each metal foil 100, so that the metal foil 100 is formed into an array 200 on a cloth or film at regular intervals. Forms a shock wave.

At this time, the metal foil array 200 can not only shorten the test preparation time, but can also be manufactured in large numbers to facilitate multiple tests, and simultaneous underwater blast tests can be conducted in various directions of the hull.

Figure 4 is a side view of the present invention. Referring to FIG. 4, an array of metal foil 100 is attached to the hull 300. In order to simulate the plane wave of an actual explosive, the metal foil is connected to each electric wire and blasting occurs, and the blasting time is adjusted through a signal generator. More details will be provided later.

[2] Other embodiments

Figure 5 shows the second embodiment. Referring to FIG. 5, this is a modified example of the array 200 formed of a plurality of metal foils 100. The frequency range can be adjusted by adjusting the thickness, shape, and spacing of the metal foil 100. For example, since the surface and internal structure are different depending on the hull, the thickness of the metal foil must be thicker to send shock waves in the target frequency band to the measurement point, or various shapes such as squares and rectangles, or the size and arrangement spacing of the shapes, etc. Adjust to apply a shock wave with a frequency similar to that of an actual explosive.

Figure 6 shows the third embodiment. Referring to FIG. 6, it is a modified example of the array 200 formed of a plurality of metal foils 100. The frequency range can be adjusted by combining different types of metal foil. For example, the required current and voltage are different for each type of metal, so the energy generated is different, and this can be used to form a shock wave of the size or frequency range desired by the user. In Figure 6, the first metal 120 and the second metal 130 are arranged uniformly, but the arrangement can be sufficiently changed according to the user's needs, and more types of metals can be used. Additionally, by mixing with the second embodiment, the frequency range can be set by forming an array by changing the thickness, shape, and spacing of each metal foil.

[3] Metal foil electroevaporation control

When a detonation signal is sent from the signal generator, the high voltage switch is activated at a time difference so that the metal foil attached to the hull is vaporized, just as the underwater shock wave of an actual explosive reaches the hull. The high-frequency shock wave generated by the electric explosion of the metal foil is transmitted directly to the hull to which the metal foil is attached as it is vaporized, making it possible to apply a shock wave in a high-frequency range similar to that of an explosive to the ship.

Figure 7 is a block diagram of the present invention. Referring to Figure 7, a delay generator, which is equipment that sends out signals from multiple channels through a single trigger, and a relay switch that receives the signal and connects the circuit are configured, and can be installed singly or in multiple shapes on the surface of the hull to be tested in various shapes. It consists of a thin metal foil that can be placed and attached, a capacitor that stores electrical energy and can quickly send electrical energy as an electrical pulse, and a power supply that supplies electrical energy to the capacitor.

At this time, by adjusting the blasting order of the attached metal foil, even if the hull is curved, the area where the shock wave hits is blasted first, as when hit by a flat shock wave arriving from afar, and the area where the shock wave hits later is blasted later through a time delay. Plane waves can be simulated in the desired way, and tests can be conducted more closely to the real thing.

Figure 8 is a graph according to voltage change. Referring to Figure 8, this is a parametric analysis through metal explosion simulation through voltage changes in the same material. Control is required to simulate plane waves using the metal foil electroevaporation.

For this control, (a) the time for the metal foil to evaporate and release the maximum pressure after the high-pressure pulse is delivered; (b) the time for the high-pressure pulse to pass through the cable from the capacitor must be calculated in advance, and all of these times must be calculated in advance. It must be taken into account and programmed into the signal generator. (a) Time is the speed of the electric pulse within the cable and can be calculated based on the impedance and resistance of the cable. (b) varies depending on the type of metal, the thickness of the foil, the shape of the length and width of the foil based on the connected electrode, and the high voltage pulse transmitted, and was studied through simulation and experiment.

[4] How to conduct the test

The method for conducting the test of the present invention will be described. The explanation below is divided into preparation stage, attachment stage, and explosion stage. First, in the preparation step, thin metal foils are placed at regular intervals on a cloth or membrane. After the preparation stage, an attachment stage is performed in which the metal foil array is attached to the surface of the hull. After the attachment stage, the explosion stage sends an electric pulse to the metal foil to form a shock wave.

At this time, in the preparation stage, the shape of the metal foil placed according to the user's needs can be modified, including the thickness and size, so that the frequency range can be adjusted, and various types of metal foil can be appropriately arranged. Metals used in metal electric explosions include copper and aluminum. In general, aluminum generates a larger explosion than copper, making it more efficient and preferable for realizing the shock wave size of the explosive.

The attachment step is a step of attaching the array formed in the preparation step to the surface of the hull. Multiple arrays are attached to the surface of the hull and can be performed simultaneously to form shock waves over a wider area, and can be easily used in multiple applications by being attached to various angles of the hull. At this time, a protective film may be attached between the hull and the metal foil to protect against electric discharge caused by metal foil blasting.

In the explosion stage, when a detonation signal is sent from the signal generator, the signal generator activates a high-voltage switch with a time difference so that the metal foil placed on the hull is vaporized as if the underwater shock wave of an actual explosive reaches the hull. The high-frequency shock wave generated by the electric explosion of the metal foil is transmitted directly to the hull to which the metal foil is attached as it is vaporized, making it possible to apply a shock wave in a high-frequency range similar to that of an explosive to the ship. In particular, when attaching metal foil, the frequency range of the shock wave can be adjusted by attaching foils with different metals, thicknesses, and shapes, and by appropriately adjusting the blasting sequence of the attached metal foil, even if the hull is curved, it can be blown from a distance. The test can be conducted more closely to the real thing by first blasting the area where the shock wave hits, as when hit by an arriving flat shock wave, and later blasting the area where the shock wave hits later through a time delay.

The present invention is not limited to the above-described embodiments, and its scope of application is diverse, and anyone skilled in the art can understand it without departing from the gist of the invention as claimed in the claims. Of course, various modifications are possible.

100: metal foil
110: Discharge protection film 120: First metal 130: Second metal
200: array
300: hull
400: signal generator

Claims (9)

It is attached to the surface of the hull and includes a plurality of metal foils that generate shock waves through electrical evaporation, and a signal generator connected to each metal foil with an electric wire and sending an electric signal,
The metal foil is electroevaporated at time intervals by the signal generator, and forms a plane wave corresponding to the shock wave of an actual explosive at the time interval, depending on the thickness, shape, spacing, and adjustment of the applied voltage of the metal foil. An underwater impact test device using metal foil electroevaporation, characterized in that it forms a frequency range corresponding to the frequency range of the explosive.
According to clause 1,
An underwater impact test device using metal foil electroevaporation, characterized in that a discharge protection film is disposed between the metal foil and the hull.
According to clause 1,
The underwater impact test device using the metal foil electroevaporation is
An underwater impact test device using metal foil electroevaporation, comprising an array in which a plurality of metal foils are arranged, and the array is attached to the surface of the hull.
delete delete According to clause 1,
The metal foil is an underwater impact test device using metal foil electroevaporation, characterized by frequency domain control using different metal materials.
In the underwater impact test method using metal foil electroevaporation using the underwater impact test device using metal foil electroevaporation of claim 1,
Metal foil array preparation step;
An attachment step of attaching the metal foil array to the hull surface;
An explosion step in which the metal foil receives an electric signal from a signal generator;
A measurement step of placing a sensor on the hull and measuring shock waves generated by the metal foil;
An underwater impact test method using metal foil electroevaporation including.
According to clause 7,
The preparation step is an underwater impact test method using metal foil electroevaporation, characterized in that a plurality of metal foils form an array on a film or cloth.
According to clause 8,
In the explosion step, the signal generator adjusts the blasting time of each metal foil so that a plane wave reaches the hull.

Images