Impact load protection structure

Abstract

The invention discloses an impact load protection structure, which shunts high-amplitude short-pulse impact load suffered by the structure through an impact load capture rod, a load transfer box and the like, constructs a stress wave propagation path, and performs interface reflection, local energy absorption design, interface and structure dissipation and the like. The impact effect of the high-amplitude short-pulse impact load on the protected structure is reduced, so that the overall impact resistance of the protection structure is improved; according to the impact load protection structure, the boundary dimension of the protected structure can not be changed, the bearing capacity of the protected structure at the impact load end can be reserved to a large extent, the structure machining difficulty is small, the improvement cost of a water entry structure with a cavitator is very low, the overall rigidity and the overall dimension of the impact load protection structure can be designed, and the service life of the impact load protection structure is prolonged. The system relates to stress wave reflection and various stress wave energy dissipation mechanisms, is large in design space and high in scene applicability, has great advantages in the aspect of impact protection, and is wide in application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of impact protection, and in particular to an impact load protection structure. Background Art

[0002] In many water entry scenarios such as air-dropped torpedoes, the structures often enter the water at a speed of hundreds of meters per second. The head of the structure will generate a huge instantaneous impact load. The strong impact load often causes damage and failure of some components in the structure. The water entry impact load has the characteristics of high amplitude and short pulse. The impact load amplitude is often in the order of GPa, and the load pulse width is often in the order of 0.1ms. After experiencing the impact load, the structure generally needs to continue to navigate in the water. For structures that use cavitation drag reduction features, the head load may reach tens of MPa. This requires the structure to have sufficient bearing capacity after experiencing the impact load. How to carry out water entry impact protection for structures with bearing capacity requirements is currently a difficult problem.

[0003] Common means of reducing load during water impact include adding sacrificial energy absorption structures to the head of the structure, adding air bags to the surface of the structure, adding jet devices to the head of the structure, and adding vents to the head of the structure. These solutions have a certain effect on reducing load, but they all change the external dimensions of the original structure. If the original structural shape cannot be quickly restored after the load reduction purpose is achieved, it may affect the subsequent underwater navigation process. For the solution of adding air bags and jet devices, the complexity of the design is significantly increased, and the use environment is also greatly restricted.

[0004] Therefore, it is necessary to develop an impact load protection structure to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to design an impact load protection structure in order to solve the above problems.

[0006] The present invention achieves the above-mentioned purpose through the following technical solutions: An impact load protection structure, comprising: The bearing base is formed into a barrel-shaped structure with an opening at the first end; the second end of the bearing base is connected to the protected body; The load transfer box is formed into a barrel-shaped structure with an opening at the first end. An outward annular protrusion is arranged at the edge of the opening at the first end of the load transfer box. The second end of the load transfer box can be slidably placed inside the bearing base, and a gap is arranged between the second end of the load transfer box and the bottom of the bearing base. The first end of the annular protrusion is connected to the first end of the bearing base. An impact load catching rod; the impact load catching rod is slidably disposed inside the load transfer box, and a first end of the impact load catching rod contacts the bottom of the load transfer box; Protective plate; the middle of the first end of the protective plate contacts the second end of the impact load capture rod, the edge of the first end of the protective plate is connected to the first end of the load transfer box and the second end of the annular protrusion, and the second end of the protective plate receives the impact load.

[0007] Furthermore, an energy absorbing buffer block is arranged between the first end of the impact load capturing rod and the inner bottom of the load transfer box.

[0008] Further, the wave impedance of the impact load catching rod is not less than the wave impedance of the protection plate material.

[0009] The beneficial effects of the present invention are: 1. Utilizing the propagation and reflection characteristics of stress waves, a part of the high-amplitude short-pulse impact signal transmitted from the end face (or protective plate) of the structure with bearing capacity is reflected and part of it is captured in the impact load capture rod. The impact signal entering the impact load capture rod is converted into the kinetic energy of the impact load capture rod. After the impact signal is captured, it instantly detaches from the original structure and takes away the impact load that should have an impact on the original structure. Subsequently, the moving impact load capture rod is intercepted by a load transfer box. After a smooth impact process is designed and constructed, the impact load is again transmitted back to the end face of the original structure with bearing capacity through the side wall of the load transfer box and the impact load and part of the impact load captured in the impact load capture rod. After constructing the stress wave propagation path, the high-amplitude short-pulse impact load is smoothed by means of interface reflection, local energy absorption design, interface and structural dissipation, etc., thereby realizing impact protection for the original structure.

[0010] 2. The impact load protection structure can retain the bearing capacity of the protected structure at the impact load end to a large extent; 3. The impact load protection structure may not change the dimensions of the protected structure; 4. The overall stiffness and overall size of the impact load protection structure can be designed, and it involves the reflection of stress waves and various stress wave energy dissipation mechanisms. The design space is large and the scenario applicability is strong; 5. The impact load protection structure is easy to process, and the cost of modifying the water entry structure with a cavitator is very low. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a structural schematic diagram of the impact load protection structure of the present invention; Figure 2 This is the impact load curve at the impact interface in a typical high-speed water impact scenario; Figure 3 It is a schematic diagram of a typical cavitator structure (cylindrical solid long rod) and the protected object; Figure 4 Typical cavitator structure suffers Figure 2 Acceleration response curve of the protected body after impact load; Figure 5 It is a schematic diagram of the structure of the present invention (excluding the buffer block) and the protected object; Figure 6 The structure of the present invention suffers Figure 2 Acceleration response curve of the protected body after impact load.

[0012] Legend: 1- impact load; 2- protection plate; 3- load transfer box; 4- impact load capture rod; 5- energy absorbing buffer block; 6- gap; 7- bearing base; 8- protected object. DETAILED DESCRIPTION

[0013] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0014] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0015] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0016] In the description of the present invention, it should be understood that the terms "upper", "lower", "inside", "outside", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are directions or positional relationships in which the product of the invention is usually placed when in use, or are directions or positional relationships commonly understood by those skilled in the art. These directions or positional relationships are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0017] Furthermore, the terms “first”, “second”, etc. are merely used for distinguishing descriptions and should not be understood as indicating or implying relative importance.

[0018] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms such as "setting" and "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0019] The specific implementation modes of the present invention are described in detail below in conjunction with the accompanying drawings.

[0020] like Figure 1 As shown, an impact load protection structure comprises: The bearing base 7 is formed into a barrel-shaped structure with an opening at the first end; the second end of the bearing base 7 is connected to the protected body 8; The load transfer box 3 is formed into a barrel-shaped structure with an opening at the first end. An outward annular protrusion is provided at the edge of the opening at the first end of the load transfer box 3. The second end of the load transfer box 3 can be slidably placed inside the bearing base 7, and a gap 6 is provided between the second end of the load transfer box 3 and the bottom of the bearing base 7. The first end of the annular protrusion is connected to the first end of the bearing base 7. The impact load catching rod 4 is slidably disposed inside the load transfer box 3, and the first end of the impact load catching rod 4 contacts the bottom of the load transfer box 3; Protective plate 2; the middle of the first end of the protective plate 2 contacts the second end of the impact load capture rod 4, the edge of the first end of the protective plate 2 is connected to the first end of the load transfer box 3 and the second end of the annular protrusion, and the second end of the protective plate 2 receives the impact load 1.

[0021] In some embodiments; Figure 1 As shown, an energy absorbing buffer block 5 is further arranged between the first end of the impact load catching rod 4 and the inner bottom of the load transfer box 3. The protective plate 2, the load transfer box 3, the impact load catching rod 4, the energy absorbing buffer block 5, and the bearing base 7 can be arranged coaxially. It can be removed according to the situation, so that the impact load catching rod 4 is in direct contact with the bottom of the load transfer box 3.

[0022] In the present invention, the impact load capture rod 4 is placed in the load transfer box 3 and can move freely. Initially, it is in close contact with the rear end face of the protective plate 2. The size of the gap 6 is determined according to the possible deformation of the load transfer box 3. The outer surface of the bearing base 7 can be a cone or the like, and is not limited to a cylindrical shape. During operation, a high-amplitude short-pulse impact load is transmitted from the protective plate 2, a part of which is transmitted into the impact load capture rod 4 through the contact interface between the protective plate 2 and the impact load capture rod 4 or partially reflected back into the protective plate 2, and the other part is directly transmitted from the edge area through the bearing base 7 to the protected body 8. The distribution ratio of the two parts of energy can be adjusted by adjusting the contact area between the protective plate 2 and the impact load capture rod 4 or adjusting the wave impedance of the impact load capture rod 4. After the impact load enters the impact load capture rod 4, the impact load capture rod 4 is disengaged from the adjustment protection plate 2 due to the reflection and stretching effect of the wave. The impact load capture rod 4 acts on the energy absorbing buffer block 5 (if any) or directly collides with the bottom of the load transfer box 3. The load transfer box 3 intercepts the impact load capture rod 4 and the impact load captured in the rod, and cuts off the path of directly transmitting to the bearing base 7 and then directly affecting the protected body 8 through the gap 6. The impact load generated by the impact and partially transmitted to the bottom of the load transfer box 3 is then transmitted back to the consolidation position of the load transfer box 3 and the protection plate 2 through the side wall of the load transfer box 3, partially transmitted to the protection plate 2, and partially transmitted to the bearing base 7.

[0023] The present invention utilizes the propagation and reflection characteristics of stress waves to partially reflect and partially capture the high-amplitude short-pulse impact signal transmitted from the end face (or protective plate 2) of the structure with bearing capacity into the impact load capture rod 4, and convert the impact signal entering the impact load capture rod 4 into the kinetic energy of the impact load capture rod 4. After the impact signal is captured, it instantly detaches from the original structure and takes away the impact load that should have an impact on the original structure. Generally speaking, the total energy of the high-amplitude short-pulse impact load is not large, and the movement speed of the impact load capture rod 4 is generally small; then, the moving impact load capture rod 4 is intercepted by the load transfer box 3, and after a smooth impact process is designed and constructed, the impact load is again transmitted back to the end face of the original structure with bearing capacity through the side wall of the load transfer box 3. By constructing the stress wave propagation path, the high-amplitude short-pulse impact load is smoothed by means of interface reflection, local energy absorption design, interface and structural dissipation, etc., thereby realizing impact protection of the original structure.

[0024] The technical features of the present invention are as follows: 1. When capturing impact loads, it should be ensured that the impact load capturing rod 4 and the protective plate 2 are tightly fitted, the length of the capturing rod is as long as possible greater than the length required for half the pulse width of the captured impact load, and the wave impedance of the capturing rod material is not less than the wave impedance of the protective plate 2 material; 2. When the length of the capturing rod is limited, a very thin foam material can be added between the protective plate 2 and the capturing rod to adjust the moment of capturing the impact load and to capture the maximum impact load segment of the capturing rod; 3. The energy of the captured impact load is controlled by adjusting the contact area between the capturing rod and the protective plate 2, the taper of the capturing rod head and the length of the capturing rod to avoid excessive total energy being captured; 4. After the capturing rod captures the impact load, if the speed of the capturing rod is relatively large, energy-absorbing material is arranged between the capturing rod and the load transfer box 3 to reduce the speed of the capturing rod. At the same time, buffer material can be added at the bottom of the capturing rod and the load transfer box 3 to make The collision process is more moderate. When the speed of the capture rod is relatively low, the capture rod can fit with the bottom of the load transfer box 3 to reduce the bottom collision process; 5. A gap 6 is designed between the load transfer box 3 and the bearing base 7 so that the collision process between the capture rod and the bottom of the load transfer box 3 does not have a direct impact on the bearing base 7, thereby cutting off the path for the load to be directly transmitted to the protected body 8; 6. The load transfer box 3 and the protective plate 2 or the bearing base 7 are consolidated at a position near the protective plate 2, so that the impact response generated by the collision between the capture rod and the bottom of the load transfer box 3 or part of the impact load transmitted to the capture rod can be transmitted back to the vicinity of the protective plate 2 through the side wall of the load transfer box 3. The side wall of the transfer box can be designed to be a hollow shape or various pleated structures to further dissipate the returned load, especially the high peak pulse load. The dissipation of the returned load can also be achieved through local plastic deformation of the side wall of the transfer box or interface friction with the bearing base 7.

[0025] In some embodiments, a typical cylindrical solid long rod cavitator is used for illustration. The cylindrical long rod has a diameter of 60 mm and a length of 300 mm. The material is steel and the mass is 6.6 kg. For the convenience of comparison, the protected body 8 is also selected as a cylindrical long rod with a diameter of 60 mm and a length of 40 mm. The material is steel and the mass is 0.88 kg. The specific structure is as follows Figure 3 The calculation adopts the typical water impact load, the peak value of the high amplitude load is 1.84GPa, the pulse width is about 50μs, and the typical water impact load curve is as follows Figure 2 The finite element calculation results show that the peak acceleration of the protected body 8 reaches 25.6×10 4 g, and repeatedly oscillates at high amplitude within the calculated 5ms duration, with the maximum amplitude still at 18×10 4 g, the acceleration response curve of the protected body after a typical cylindrical solid long rod cavitator is subjected to water impact load is as follows: Figure 4As shown. The protective structure proposed in this application is adopted, the thickness of the protective plate 2 is 10mm, the thickness of the shell of the load transfer box 3 is 4mm, the diameter of the impact load capture rod 4 is 40mm and the length is 244mm, no energy absorption buffer block 5 is designed, the diameter of the gap 6 is 40mm and the length is 2mm, and all structural materials are also steel. The specific structure is as follows Figure 5 The finite element calculation results show that the overload peak value of the protected body 8 is reduced to 10.3×10 4 g, and then dropped rapidly. Within 5ms calculation time, the overload peak value gradually stabilized at 3×10 4 g, the load reduction effect is significant. The acceleration response curve of the protected body after the protective structure proposed in this application is subjected to the water impact load is as follows: Figure 6 shown.

[0026] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An impact load protection structure, characterized in that: include: The bearing base is formed into a barrel-shaped structure with an opening at the first end; the second end of the bearing base is connected to the protected body; load transfer box; The load transfer box is formed into a barrel-shaped structure with an opening at the first end. An outward annular protrusion is arranged at the edge of the opening at the first end of the load transfer box. The second end of the load transfer box can be slidably placed inside the bearing base, and a gap is arranged between the second end of the load transfer box and the bottom of the bearing base. The first end of the annular protrusion is connected to the first end of the bearing base. shock load catching rod; The impact load capture rod is slidably disposed inside the load transfer box, and the first end of the impact load capture rod is in contact with the bottom of the load transfer box; Protective plate; the middle of the first end of the protective plate contacts the second end of the impact load capture rod, the edge of the first end of the protective plate is connected to the first end of the load transfer box and the second end of the annular protrusion, and the second end of the protective plate receives the impact load.

2. The impact load protection structure according to claim 1, characterized in that: An energy absorbing buffer block is also arranged between the first end of the impact load capturing rod and the inner bottom of the load transfer box.

3. The impact load protection structure according to claim 1, characterized in that: The wave impedance of the impact load catching rod shall not be less than the wave impedance of the protective plate material.

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