Anti-drilling composite structure with system-breaking effect

Abstract

The application discloses a kind of anti-drilling composite structures with system breaking effect, it is related to the technical field of protective equipment, it solves the current existing protective structure still belongs to passive defense, completely rely on steel ball rotation makes drill tip skid;Once drill bit overcomes the initial skid of steel ball by means such as exerting greater pressure, it can be stably cut technical problem;The application comprises outer layer and substrate, a plurality of cone units and spherical units are arranged on the surface of the substrate towards the outer layer side, a plurality of the spherical units are distributed between adjacent cone units, the distance from the top of the spherical unit to the substrate is greater than the distance from the top of the cone unit to the substrate;Its purpose is that cone unit and spherical unit cooperate, resulting in spherical unit starts high-speed rotation, and then trigger drill pipe bounce instability, the side edge of drill pipe still in high-speed rotating state after instability and the edge line of regular triangular cone occur random violent collision, finally make drill pipe side edge collapse.

Description

Technical Field

[0001] This invention belongs to the field of protective equipment technology, specifically relating to a drill-resistant composite structure with systemic destructive effects. Background Technology

[0002] Current protective technologies mostly focus on passive defense: First, strengthening the protective structure, such as increasing the strength and thickness of the steel plates. While this method significantly increases the difficulty of breaching, it is essentially still a passive approach and cannot damage attack tools (such as electric drills). Second, using sandwiched interference structures. For example, using two layers of steel plates with resin or rubber sandwiched between them; the drawback is that it can only delay but not prevent penetration.

[0003] The existing invention patent "Anti-drilling Structure" (200710022968.4) discloses an anti-drilling structure comprising an outer wall layer, an inner wall layer, and multiple steel balls arranged in the inner wall layer, which can provide good anti-drilling effect. However, this protective structure is still a passive defense, relying entirely on the rotation of the steel balls to cause the drill tip to slip. Once the drill bit overcomes the initial slippage of the steel balls by applying greater pressure, it can perform stable cutting. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a drill-resistant composite structure with a systemic destructive effect. The spherical unit and the trihedral cone unit are designed to actively destroy the side cutting edge of the electric drill. If the drill bit first contacts the trihedral cone unit, the drill bit cannot remain on the surface of the cone unit, nor can it find a suitable cutting position on its surface. The rotating drill bit can only slide downwards along the inclined surface of the cone unit and contact the adjacent spherical unit at a certain position, causing the spherical unit to begin high-speed rotation, thereby triggering the drill rod to bounce and become unstable. After instability, the side cutting edge of the drill rod, still in a high-speed rotating state, will inevitably collide randomly and violently with the sharp edges of the hard trihedral cone, ultimately causing the side cutting edge of the drill rod to break and the drill rod to be damaged.

[0005] The technical solution adopted in this invention is as follows:

[0006] A drill-resistant composite structure with systemic destructive effect includes an outer layer and a substrate, with a cavity formed between the outer layer and the substrate. Inside the cavity, several conical units and spherical units are distributed on the surface of the substrate facing the outer layer. The spherical units are spaced apart between adjacent conical units, and the distance from the top of the spherical unit to the substrate is greater than the distance from the top of the conical unit to the substrate.

[0007] Using the above technical solution, the spherical unit and the regular trihedral cone unit are designed to actively destroy the side cutting edge of the electric drill. If the drill bit first contacts the regular trihedral cone unit, the drill bit cannot stay on the surface of the cone unit, nor can it find a suitable cutting position on its surface. The rotating drill bit can only slide downwards along the inclined surface of the cone unit and contact the adjacent spherical unit at a certain position, causing the spherical unit to start rotating at high speed, thereby triggering the drill rod to bounce and become unstable. After instability, the side cutting edge of the drill rod, which is still in a state of high-speed rotation, will inevitably have a random and violent collision with the sharp edge of the hard regular trihedral cone, eventually causing the side cutting edge of the drill rod to break and the drill rod to be damaged.

[0008] Preferably, several cone units and spherical units are arranged in an array on the surface of the substrate, and at least a number of cone units are provided in the circumferential field of any spherical unit, and at least a number of spherical units are also provided in the circumferential field of any cone unit.

[0009] Preferably, the array of cone units is a honeycomb array, with six adjacent cone units forming a hexagonal region. At least one spherical unit is disposed within the hexagonal region, and the hexagonal regions are repeatedly arranged along the planar direction, thereby forming a honeycomb periodic structure on the surface of the substrate.

[0010] Using the above technical solution, the honeycomb array forms a hexagonal symmetrical uniform skeleton of the cone unit in the plane, and spherical units are arranged in the hexagonal area. As a result, after the drill bit penetrates the outer protective plate, regardless of whether the initial contact point is on the cone or the sphere, it will contact the spherical unit within a short distance and trigger instability. At the same time, during the radial swing process after instability, the drill bit side edge has a high probability of high-frequency random collision with the cone edge in all directions, which accelerates the chipping and damage of the edge and makes it difficult to form a stable cutting point.

[0011] Preferably, the cone unit is a regular trihedral cone.

[0012] Preferably, the spherical unit includes a spherical element and a groove adapted to the size of the spherical element, the groove being formed on a substrate, and the spherical element being rotatably disposed inside the groove.

[0013] Preferably, the ratio of the depth of the groove to the diameter of the spherical element is 0.5:1, and the diameter of the groove opening is 0.05~0.1mm smaller than the diameter of the spherical element.

[0014] Preferably, the height of the cone unit is 8~20mm, and the diameter of the spherical element is 18~30mm.

[0015] Preferably, the cellular periodic array includes a local perturbation array, which consists of spherical elements of two different heights, positioned between each pair of adjacent arrays.

[0016] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0017] 1. The design of the spherical and trihedral conical units is intended to actively destroy the side cutting edge of the drill bit. If the drill bit first contacts the trihedral conical unit, the drill bit cannot remain on the surface of the conical unit, nor can it find a suitable cutting position on its surface. The rotating drill bit can only slide downwards along the inclined surface of the conical unit and contact the adjacent spherical unit at a certain position, causing the spherical unit to start rotating at high speed, which in turn triggers the drill rod to bounce and become unstable. After instability, the side cutting edge of the drill rod, which is still rotating at high speed, will inevitably collide randomly and violently with the sharp edges of the hard trihedral conical, ultimately causing the side cutting edge of the drill rod to break and the drill rod to be damaged.

[0018] 2. The honeycomb array enables the cone unit to form a hexagonal symmetrical uniform skeleton in the plane, and spherical units are arranged in the hexagonal area. As a result, after the drill bit penetrates the outer protective plate, regardless of whether the initial contact point is on the cone or the sphere, it will contact the spherical unit within a short slip distance and trigger instability. At the same time, during the radial swing after instability, the drill bit side edge has a high probability of high-frequency random collision with the cone edge in all directions, which accelerates the chipping and damage of the edge and makes it difficult to form a stable cutting point.

[0019] 3. Six conical units are distributed around the perimeter. The six edges of the conical units near the spherical units are like six knives placed around the spherical units. When the drill bit strikes, if the drill bit hits the spherical unit first, the spherical element rotates, the drill rod becomes unstable, and it randomly hits the six sharp conical edges around the spherical unit, which then damage the side edge of the drill rod. If the drill bit first contacts the side of the conical unit, the drill bit will slide towards the spherical unit located in the center along the slope of the side of the conical unit until it contacts the spherical element, which further causes the drill rod to become unstable and hit the edge of the conical unit.

[0020] 4. The structure of the trihedral cone unit is adopted. The fewer the sides of the cone unit, the sharper the included angle between the faces, and the stronger the destructive effect on the side edge of the drill pipe. Attached Figure Description

[0021] The present invention will be described by way of example and with reference to the accompanying drawings, wherein:

[0022] Figure 1 This is a schematic diagram of the distribution structure of the cone unit and the sphere unit in this invention;

[0023] Figure 2 This is a schematic diagram of the distribution structure of the outer layer and the substrate in this invention.

[0024] Figure Labels

[0025] 1-Cone unit, 2-Sphere unit, 3-Outer layer, 4-Substrate. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] The following is combined with Figures 1-2 The present invention will be described in detail below.

[0028] A drill-resistant composite structure with systemic destructive effects, see attached figure. Figure 2 The system comprises an outer layer 3 and a substrate 4, with a cavity formed between them. Inside the cavity, several conical units 1 and spherical units 2 are distributed on the surface of the substrate 4 facing the outer layer 3. The spherical units 2 are spaced apart from adjacent conical units 1, and the distance from the top of each spherical unit 2 to the substrate 4 is greater than the distance from the top of each conical unit 1 to the substrate 4. The spherical units and the trihedral conical units 1 are designed to actively destroy the side cutting edge of the drill bit. If the drill bit first contacts the trihedral conical unit 1, the drill bit cannot stay on the surface of the conical unit 1, nor can it find a suitable cutting position on its surface. The rotating drill bit can only slide downwards along the inclined surface of the conical unit 1 and contact the adjacent spherical unit at a certain position, causing the spherical unit to start rotating at high speed, thereby triggering the drill bit to bounce and become unstable. After instability, the side cutting edge of the drill bit, which is still rotating at high speed, will inevitably collide randomly and violently with the sharp edges of the hard trihedral conical unit, ultimately causing the side cutting edge of the drill bit to break and the drill bit to be damaged.

[0029] Among them, the cone unit 1 is made of AF1410 ultra-high strength steel; the outer layer 3 is made of flat solid metal plate, which is made of ultra-high strength alloy steel such as 34CrNiMo6 or 42CrMo, with a thickness of 10~15mm, and the surface is covered with thermal spray carbonized coating with a hardness of HR C40~HRC 60.

[0030] The distance between the outer layer 3 and the substrate 4 is 5~8cm.

[0031] AF1410 features high strength, high fracture toughness, excellent machinability, and high fatigue resistance. Its high strength and fracture toughness ensure that when the drill bit's side edge buckles and impacts the sharp corner of the cone unit 1, the cone unit 1 can effectively absorb the impact energy. Through microscopic plastic deformation, cracks are generated and propagated, ensuring the cone edge remains intact and does not break or deform, allowing the drill bit damage process to continue. AF1410's excellent machinability guarantees this performance requirement, while its high fatigue resistance ensures that the cone edge will not become blunt or fail under repeated impacts, extending the service life of the entire protection system.

[0032] 34CrNiMo6 exhibits high yield strength, high toughness, high wear resistance, and high fatigue resistance. High yield strength significantly extends the drilling time. High toughness ensures that the hole wall formed after the drill bit penetrates the outer liner (3rd layer) is smooth, intact, and hard, a necessary condition for the subsequent rigid constraint of the drill rod's rear end. High wear resistance reduces wear on the drill tip during the penetration of the outer liner (3rd layer), alleviating the protective pressure on the inner substrate (4th layer). High fatigue resistance ensures that when the drill rod becomes unstable and alternating stress is applied to the hole wall, the outer liner (3rd layer) at the hole wall will not develop cracks due to fatigue, preventing constraint failure.

[0033] The surface roughness of the spherical element is less than 0.2 μm. When the surface roughness is less than 0.2 μm, it may cause greater friction when the spherical element rotates, which reduces the instability effect on the drill pipe. In addition, when the surface roughness is less than 0.2 μm, it can avoid providing a suitable cutting force point for the drill pipe. The spherical element is made of high carbon chromium bearing steel with a hardness of not less than HRC60. High carbon chromium bearing steel is specially designed to withstand high frequency and high stress loads. It has extremely strong fatigue resistance and features high cleanliness and uniform structure, which is conducive to grinding to the surface roughness or mirror cleanliness required by the process, so as to achieve low friction rotation of spherical unit 2.

[0034] In this embodiment, several cone units 1 and sphere units 2 are arranged in an array on the surface of the substrate 4. At least a plurality of cone units 1 are provided in the circumferential field of any sphere unit 2, and at least a plurality of sphere units 2 are also provided in the circumferential field of any cone unit 1.

[0035] In this embodiment, refer to the appendix. Figure 1The array of the cone units 1 is a honeycomb array, with six adjacent cone units 1 forming a hexagonal region. A spherical unit 2 is arranged within the hexagonal region. The hexagonal regions are repeatedly arranged along the plane, thereby forming a honeycomb periodic structure on the surface of the substrate 4. The honeycomb array makes the cone units 1 form a hexagonal symmetrical uniform skeleton in the plane, and the spherical units are arranged within the hexagonal regions. As a result, after the drill bit penetrates the outer protective plate 3, regardless of whether the initial contact point is located on the cone or the sphere, it will contact the spherical unit within a short distance and trigger instability. At the same time, during the radial swing after instability, the side edge of the drill bit has a high probability of high-frequency random collisions with the cone edge in all directions, which accelerates the chipping and damage of the edge and makes it difficult to form a stable cutting point.

[0036] In this embodiment, the cone unit 1 is a regular trihedral cone.

[0037] In this embodiment, the spherical unit 2 includes a spherical element and a groove adapted to the size of the spherical element. The groove is formed on the substrate 4, and the spherical element is rotatably disposed inside the groove.

[0038] In this embodiment, the ratio of the depth of the groove to the diameter of the spherical element is 0.5:1, and the diameter of the groove opening is 0.05~0.1mm smaller than the diameter of the spherical element.

[0039] The diameter of the spherical element is 18-30mm; the diameter of the drill bit is generally 5-20mm. To prevent the drill bit from straddling the sphere and finding a suitable point of force when using a larger diameter drill bit, the contact arc surface of the sphere needs to be wide enough in this case. Therefore, the diameter of the sphere is not less than 18mm. At the same time, due to the compactness of the overall structure, an excessively large sphere would result in an overly sparse unit array, so the above range was chosen.

[0040] In this embodiment, the height of the cone unit 1 is 8~20mm.

[0041] Among them, the base of the cone unit 1 is an equilateral triangle with a side length of 10~20mm.

[0042] In this embodiment, an annular limiting lip is provided at the groove opening; thus, the spherical element is not dislodged under impact load, while not significantly increasing the rotational resistance.

[0043] In this embodiment, the center-to-center distance between the cone units 1 is approximately equal to the length of the base of the cone unit 1 plus the diameter of the sphere.

[0044] The specific design parameters for Examples 1-7 and Comparative Examples 1-3 are as follows:

[0045] Table 1: Specific design parameters for Examples 1-7 and Comparative Examples 1-3

[0046]

[0047] It should be noted in Table 1 that in Example 7, a local disturbance array is set in the periodic array, and the height of the spherical element between each two adjacent arrays is adjusted. In Example 7, the diameters of two adjacent spherical units 2 are 25mm and 30mm respectively, so that the attacker cannot determine the best entry point through a single test drill.

[0048] Comparative Example 4

[0049] The other parameters are the same as in Example 2, except that the cone unit 1 is laid out in a square, and the sphere unit 2 is placed at the intersection of the four vertices of the cone unit 1.

[0050] Comparative Example 5

[0051] The other parameters are the same as in Example 2, except that the cone unit 1 is laid out in an equilateral triangle and the sphere unit 2 is placed at the center of the three vertices.

[0052] Comparative Example 6

[0053] The difference is that only spherical unit 2 is set, the diameter of spherical unit 2 is 30mm, and the distance between the center points of spherical unit 2 is 1.2 * the diameter of spherical unit 2, which is 36mm.

[0054] To verify the anti-drilling effect of the present invention, an experiment was conducted using a φ10 mm HSS high-speed steel drill bit. The drill bit power was 1000 W, the rotation speed was 1200 rpm, and the axial pressure was approximately 150 N. The protective structure sample included an outer 334CrNiMo6 steel plate, 10 mm thick, with a thermally sprayed carbide coating on the surface, a hardness of HRC 40~60, a substrate 4, and conical units 1 and spherical units 2 arranged on the surface of the substrate 4. During the experiment, the drilling time, drill bit damage, and drilling efficiency were recorded, and the differences in protective performance between the comparative examples and the comparative embodiment are shown in Table 2 below.

[0055] Table 2: Comparison of protective performance differences between Examples 1-7 and Comparative Examples 1-6.

[0056]

[0057] Both Example 1 and Example 2 use a standard honeycomb array arrangement of trihedral cone unit 1 and spherical unit 2. In Example 2, the cone slope is larger. After the drill bit contacts the cone surface, it slides along the inclined surface to the spherical unit 2, triggering instability. The drill rod swings violently, and the side edge of the drill bit shows obvious to severe cracking. The drilling time is 305 s and 335 s, respectively, and the drilling efficiency is as low as 0.05~0.06 mm / s.

[0058] Example 3 and Example 4 have slightly larger bottom edges and different heights. Example 4 has a larger slope, and after the drill bit slips and triggers instability, it produces medium to strong oscillations, resulting in significant damage to the drill bit. The drilling time is longer than that of Example 3, indicating that the height and slope of the cone have a significant impact on the instability of the drill rod and the degree of damage to the drill bit.

[0059] Examples 5 and 6 increase the height or slope of the cone, making the drill bit slip path longer, enhancing the instability effect, and correspondingly extending the drilling time, while reducing drilling efficiency.

[0060] Example 7 employs a perturbation array design. The height and diameter of adjacent spherical units 2 have slight differences, making it impossible for the drill bit to find a stable cutting point. The drill rod swings randomly and violently, and the drill bit suffers severe chipping or even partial breakage. The drilling time is the longest and the drilling efficiency is the lowest, demonstrating the advantage of the perturbation array in terms of system destructive effects.

[0061] Comparative Examples 1-6, due to their smaller cone slope or the absence of a honeycomb-like collaborative structure in the cone arrangement, allow the drill bit to easily form a stable cutting point upon contact with the cone or sphere, resulting in minimal drill rod oscillation and only slight or moderate drill bit wear. Comparative Example 1, with its 50° slope, allows the drill bit to quickly find the cutting point, producing only slight wear, achieving the shortest penetration time and highest drilling efficiency. Comparative Examples 2-5, although incorporating cone or sphere units 2, lack a systemic destructive effect, resulting in limited drill rod instability, slight or moderate drill bit damage, penetration times of 170-215 s, and drilling efficiencies between 0.14 and 0.19 mm / s. Comparative Example 6, with only sphere units 2, lacks the ridge impact destructive effect provided by cone unit 1, but the drill bit cannot form a stable cutting point on the sphere, leading to decreased drilling efficiency and a slightly increased penetration time compared to Comparative Example 1. However, it cannot damage the drill bit, and its protective effect is far inferior to the systemic destructive structure of this invention.

[0062] This invention, through a rationally designed honeycomb array of trihedral cone units 1 and spherical units 2, and a disturbance array, not only prolongs the drilling time and reduces drilling efficiency, but also triggers drill rod instability, causing the drill bit side edge to randomly collide with the cone edge at high frequency, resulting in significant fractures, thereby achieving a system destructive effect and effectively improving the protective performance.

[0063] It should be noted that:

[0064] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A drill-resistant composite structure with systemic destructive effects, characterized in that, It includes an outer layer (3) and a substrate (4), and a cavity is formed between the outer layer (3) and the substrate (4). Inside the cavity, several cone units (1) and spherical units (2) are distributed on the surface of the substrate (4) facing the outer layer (3). Several spherical units (2) are distributed at intervals between adjacent cone units (1). The distance from the top of the spherical unit (2) to the substrate (4) is greater than the distance from the top of the cone unit (1) to the substrate (4).

2. The anti-drilling composite structure with systemic destructive effect according to claim 1, characterized in that, Several cone units (1) and sphere units (2) are arranged in an array on the surface of the substrate (4). At least a number of cone units (1) are provided in the circumferential field of any sphere unit (2), and at least a number of sphere units (2) are also provided in the circumferential field of any cone unit (1).

3. The anti-drilling composite structure with systemic destructive effect according to claim 1, characterized in that, The array of the cone units (1) is a honeycomb array, with six adjacent cone units (1) forming a hexagonal region. At least one spherical unit (2) is provided in the hexagonal region. The hexagonal regions are repeatedly arranged along the planar direction, thereby forming a honeycomb periodic structure on the surface of the substrate (4).

4. The anti-drilling composite structure with systemic destructive effect according to claim 1, characterized in that, The cone unit (1) adopts a regular trihedral cone shape.

5. The anti-drilling composite structure with systemic destructive effect according to claim 1, characterized in that, The spherical unit (2) includes a spherical element and a groove adapted to the size of the spherical element. The groove is formed on the substrate (4), and the spherical element is rotatably disposed inside the groove.

6. The anti-drilling composite structure with systemic destructive effect according to claim 5, characterized in that, The ratio of the depth of the groove to the diameter of the spherical element is 0.5:1, and the diameter of the groove opening is 0.05~0.1mm smaller than the diameter of the spherical element.

7. The anti-drilling composite structure with systemic destructive effect according to claim 6, characterized in that, The height of the cone unit (1) is 8~20mm, and the diameter of the spherical element is 18~30mm.

8. The anti-drilling composite structure with systemic destructive effect according to claim 3, characterized in that, In the cellular periodic array, a local perturbation array is set up, that is, two kinds of spherical elements with different heights are set up between each two adjacent arrays.

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