Superfine-diameter optical fiber towed line array vibration reduction and isolation module

Abstract

The invention discloses a superfine-diameter optical fiber towed line array vibration reduction and isolation module, which relates to the field of underwater acoustic sensing, and comprises two array connectors, and a sheath is arranged between the two array connectors; the two force bearing pieces are fixedly installed on the corresponding array connectors, the other ends of the force bearing pieces extend into the sheath, and force bearing rope holes and elastic rope holes are formed in the force bearing pieces; the bearing skeletons are arranged at equal intervals along the axial direction of the sheath; one end of the elastic rope is fixed to one force bearing piece through the elastic rope hole, and the other end of the elastic rope sequentially penetrates through the force bearing frameworks and then is fixed to the elastic rope hole of the other force bearing piece; the force-bearing rope is divided into two strands, penetrates out of the force-bearing rope hole of one force-bearing piece, is arranged along the outer wall of each force-bearing framework, penetrates into the force-bearing rope hole of the other force-bearing piece and is combined into one strand; and the flexible optical cables are arranged along the outer walls of the bearing frameworks. According to the invention, the zero-buoyancy balancing of the whole array is realized, the development of the array with the diameter phi of 16 mm and the low-speed towing test on the lake are completed, and the method has important application value in the field of underwater acoustic sensing.

Description

Technical Field

[0001] The present invention relates to the field of underwater acoustic sensing, and particularly to an ultra-fine diameter fiber optic towed array vibration isolation and damping module. Background Art

[0002] With the proposal of the concept of "distributed warfare", naval powers around the world have regarded the development of surface and underwater unmanned platforms as important equipment preparations for practicing this combat method. Compared with the characteristics of large displacement and large payload capacity of manned platforms, the accommodation space and payload capacity of unmanned platforms are very limited, which strongly restricts the scale and detection ability of traditional towed array systems. Therefore, it is urgent to develop smaller-sized hydrophones and thinner-diameter arrays. It is reported that countries such as Singapore and the UK have carried out the research and development of ultra-fine diameter hydrophones and line arrays. Recently, in 2017, the digital thin line array with an outer diameter of 20 mm and a length of 20 m developed by the UK's AutoNaut company and Seiche company has high acoustic sensitivity within a broadband (10 Hz - 2 kHz), the array element spacing is 0.25 m, and they jointly carried out experimental research towed by an unmanned surface vehicle (USV). This type of USV-towed thin line array is mainly used for the detection and defense of submarines and other underwater targets. The British Systems Engineering & Assessment Ltd (SEA) reported in Jane's Defence Weekly in 2018 developed an ultra-fine towed line array Krait Array specifically for small anti-submarine platforms such as small ships, unmanned surface vessels, and underwater unmanned vehicles. It integrates 128 low-power, miniature, high-sensitivity, broadband hydrophones and 32 miniature non-acoustic sensors, achieving an outer diameter size of 16 mm and a working depth of 300 m. This ultra-fine diameter array has entered the final test stage. However, it is understood from the report that foreign ultra-fine hydrophones and arrays mostly adopt digital electrical hydrophone solutions, and their applications are mainly aimed at small platforms, and there is a lack of reports on ultra-thin line array technology based on fiber optic hydrophones abroad.

[0003] The existing towed array vibration isolation module is restricted by the zero buoyancy requirement and it is difficult to achieve engineering applications of ultra-fine diameter miniaturization. To meet the application requirements of ultra-fine diameter fiber optic towed array sonar, it is necessary to simultaneously carry out research on ultra-fine diameter fiber optic towed array vibration isolation and damping modules to solve the problems in the miniaturization design of vibration isolation and damping modules, such as the design of the framework, the laying of elastic ropes, the laying of optical cables, zero buoyancy trimming, and the filling of solid glue. Summary of the Invention

[0004] The object of the present invention is to overcome the deficiencies existing in the prior art, and to provide an ultra-thin diameter fiber optic towed array vibration isolation and damping module, which overcomes the process difficulties in manufacturing a fiber optic towed array with a length of 30 m and a diameter of Φ16 mm. A variety of functional components such as array connectors, elastic ropes, load-bearing ropes, load-bearing skeletons, flexible optical cables, and load-bearing components are integrated in its internal limited space, realizing the suppression ability of the vortex-induced jitter of the ultra-thin diameter fiber optic towed line array at low tow speeds. This vibration isolation and damping module can be applied to fiber optic towed array sonar systems for military and civilian products. The ultra-small design can effectively relieve the load pressure on warships and has good application prospects in the field of underwater acoustic sensing.

[0005] The object of the present invention is achieved by the following technical solutions: This ultra-thin diameter fiber optic towed array vibration isolation and damping module includes:

[0006] Two array connectors are respectively arranged at both ends of the vibration isolation module, and a sheath is installed between the two array connectors;

[0007] Two load-bearing components are fixedly installed on the corresponding array connectors. The other end of the load-bearing component extends into the sheath and is provided with a load-bearing rope hole and an elastic rope hole;

[0008] Several load-bearing skeletons are arranged at equal intervals along the axial direction of the inner cavity of the sheath to support the sheath;

[0009] An elastic rope is threaded through the sheath. One end of the elastic rope is fixed to a load-bearing component through the elastic rope hole, and the other end sequentially passes through each load-bearing skeleton and then is fixed to the elastic rope hole of the other load-bearing component;

[0010] A load-bearing rope is threaded through the sheath. The load-bearing rope is divided into two strands and passes out of the load-bearing rope hole of a load-bearing component. After arranging the wire along the outer wall of each load-bearing skeleton, it passes into the load-bearing rope hole of the other load-bearing component and merges into one strand; and

[0011] A flexible optical cable is threaded through the sheath and arranged along the outer wall of each load-bearing skeleton. Both ends of the flexible optical cable are respectively connected to the corresponding array connectors.

[0012] As a further technical solution, a cylindrical platform is provided at one end of the load-bearing component fixed to the array connector. The cylindrical platform is embedded in the array connector and fixed by a compression ring.

[0013] As a further technical solution, an elastic rope threading hole is provided at the center of each load-bearing skeleton for the elastic rope to pass through. Load-bearing rope placement grooves are symmetrically provided on both sides of the outer wall of the load-bearing skeleton for the load-bearing rope to be placed and routed. A number of flexible optical cable installation grooves are evenly distributed on the outer wall of the load-bearing skeleton between the two load-bearing rope placement grooves for the flexible optical cable to be placed and routed; The load-bearing skeleton is made of glass microsphere material.

[0014] As a further technical solution, the sheath is made of PU material and is made into a tubular structure with an outer diameter not exceeding Φ15 mm.

[0015] As a further technical solution, the load-bearing rope is a flat wear-resistant rope, and its breaking tensile force is not less than 150 kg.

[0016] As a further technical solution, the flexible optical cable adopts a metal flexible armored pipe coated with Teflon, and a pair of thin-diameter anti-microbending optical fibers are arranged in the flexible optical cable.

[0017] As a further technical solution, the inner cavity of the sheath is filled with low-density solid glue, and the density after curing does not exceed 0.90 g / cm 3 .

[0018] As a further technical solution, the array connector and the load-bearing member are made of TC4 titanium alloy material, and have a tensile strength of not less than 895 MPa and a specified residual elongation stress of not less than 830 MPa.

[0019] As a further technical solution, the elastic rope is an ultra-fine single-braided nylon rope with a diameter of Φ2 mm, and the elongation at low towing speed does not exceed 15%.

[0020] The beneficial effects of the present invention are as follows:

[0021] 1. By using materials such as flexible optical cables, low-density polyurethane glue, and low-density skeletons, the diameter of the towed line array vibration isolation and damping module made does not exceed 16 mm, realizing the ultra-small design of the fiber optic towed line array sonar, and meeting the limited load capacity requirements of underwater acoustic sensing unmanned platforms;

[0022] 2. Rope passing holes for the load-bearing rope and the elastic rope are provided on the load-bearing member. After passing through the rope passing holes, the two ropes are evenly arranged between the load-bearing members and do not interfere with each other;

[0023] 3. The load-bearing skeletons are arranged at equal intervals in the array to support the sheath, and glass microbeads are used as materials, which have strong plasticity, light specific gravity, and strong pressure resistance, meeting the usage scenario requirements of the working depth in shallow waters;

[0024] 4. The elastic rope is preferably an ultra-fine single-braided nylon rope with a diameter of Φ2 mm, and the elongation at low towing speed does not exceed 15%. The thin rope is threaded and laid through the elastic rope holes on the load-bearing member and the elastic rope passing holes on the load-bearing skeleton;

[0025] 5. The load-bearing rope is preferably a flat wear-resistant rope, and its breaking tensile force is not less than 150 kg, meeting the tensile requirements of the ultra-fine diameter fiber optic towed line array at low towing speed;

[0026] 6. A tubular structure outer sheath with an outer diameter not exceeding Φ15 mm is used as the elastic load-bearing auxiliary structure of the line array, effectively reducing the vortex-induced vibration of the fiber optic towed line array at low towing speed;

[0027] 7. The remaining space inside the sheath is filled with low-density solid glue, which has strong fluidity before curing and can fill the array at high speed. After curing, the density is not more than 0.90 g / cm 3 , and the overall array realizes a zero-buoyancy design. After forming the array, it meets the zero-buoyancy requirement of seawater, and the diameter range is 15.50 mm to 15.99 mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic structural diagram of the present invention.

[0029] Figure 2 It is a schematic structural diagram of the load-bearing member in the present invention.

[0030] Figure 3 It is a schematic structural diagram of the load-bearing framework in the present invention.

[0031] Figure 4 It is a schematic diagram of the tension-elongation relationship of the elastic rope in the present invention.

[0032] Description of the reference numerals: array connector 1, load-bearing member 2, load-bearing rope 3, load-bearing framework 4, sheath 5, flexible optical cable 6, elastic rope 7, compression ring 8, load-bearing rope hole 9, elastic rope hole 10, load-bearing rope laying groove 11, elastic rope threading hole 12, flexible optical cable installation groove 13, cylindrical platform 14. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] The present invention will be described in detail below with reference to the drawings:

[0034] Embodiment: As shown in the attached Figures 1 to 4 figure, this ultra-fine diameter fiber optic towed array vibration isolation and damping module includes an array connector 1, a load-bearing member 2, a load-bearing rope 3, a load-bearing framework 4, a sheath 5, a flexible optical cable 6, an elastic rope 7, a compression ring 8, a load-bearing rope hole 9, an elastic rope hole 10, a load-bearing rope laying groove 11, an elastic rope threading hole 12, a flexible optical cable installation groove 13, and a cylindrical platform 14.

[0035] Referring to the attached Figure 1 figure, two array connectors 1 are respectively arranged at both ends of the vibration isolation module, and a sheath 5 is installed between the two array connectors 1. Preferably, the sheath 5 is made of PU material and is formed into a tubular structure with an outer diameter not exceeding Φ15 mm. As an elastic load-bearing auxiliary structure of the linear array, it can effectively reduce the vortex-induced vibration of the fiber optic towed array at low towing speeds. A number of load-bearing frameworks 4 are arranged at equal intervals along the axial direction of the inner cavity of the sheath 5 to support the sheath 5. The load-bearing framework 4 is made of glass microsphere material, has strong plasticity, light specific gravity, and strong pressure resistance, and meets the usage scenario requirements of the working depth in shallow waters.

[0036] A load-bearing member 2 is correspondingly installed on each array connector 1, as shown in Figure 1 , 2As shown, one end of the load-bearing member 2 fixed to the array connector 1 is provided with a cylindrical platform 14. The cylindrical platform 14 is embedded in the array connector 1, compressed by a retaining ring 8, and fixed by screws to prevent rotation, thereby achieving tensile resistance and fixation. Further, the other end of the load-bearing member 2 extends into the sheath 5, and load-bearing rope holes 9 and elastic rope holes 10 are formed in the load-bearing member 2. Preferably, the array connector 1 and the load-bearing member 2 are made of TC4 titanium alloy material, having a tensile strength of not less than 895 MPa and a specified residual elongation stress of not less than 830 MPa.

[0037] Refer to the attached Figure 1 、 3 , the elastic rope 7 is threaded through the sheath 5, and an elastic rope threading hole 12 is formed in the center of each load-bearing skeleton 4 for the elastic rope 7 to pass through. One end of the elastic rope 7 is fixed to one of the load-bearing members 2 through the elastic rope hole 10, and the other end of the elastic rope 7 sequentially passes through each load-bearing skeleton 4 and then is fixed to the elastic rope hole 10 of the other load-bearing member 2.

[0038] The load-bearing rope 3 is threaded through the sheath 5. The load-bearing rope 3 is divided into two strands and passes out of the load-bearing rope hole 9 of one of the load-bearing members 2. After being arranged along the outer wall of each load-bearing skeleton 4, it penetrates into the load-bearing rope hole 9 of the other load-bearing member 2 and is combined into one strand. Correspondingly, load-bearing rope placement grooves 11 are symmetrically formed on both sides of the outer wall of the load-bearing skeleton 4 for the load-bearing rope 3 to be placed and routed. At the same time, a plurality of flexible optical cable installation grooves 13 are evenly distributed on the outer wall of the load-bearing skeleton 4 between the two load-bearing rope placement grooves 11 for the flexible optical cable 6 to be placed and routed. The flexible optical cable 6 is threaded through the sheath 5 and is arranged along the outer wall of each load-bearing skeleton 4, and both ends of the flexible optical cable 6 are respectively connected to the corresponding array connectors 1. Preferably, the flexible optical cable 6 is a metal flexible armored pipe coated with Teflon, and a pair of thin-diameter anti-microbend optical fibers are placed in the flexible optical cable 6. Since both ends of the flexible optical cable 6 are respectively connected to the array head and tail connectors, the length redundancy design can be ensured under the condition of making full use of the limited space, meeting the requirements of low insertion loss transmission of optical signals.

[0039] Preferably, the load-bearing rope 3 is a flat-shaped wear-resistant rope, and its breaking resistance is not less than 150 kg, meeting the tensile requirements of the ultra-fine diameter optical fiber towed array at low tow speeds. The elastic rope 7 is a super-fine single-braided nylon rope with a diameter of Φ2 mm, and its elongation at low tow speeds does not exceed 15%. The relationship between the tension it receives and the elongation is shown in Figure 4 . Since the elastic rope is relatively thin, the traditional process cannot achieve threading of Φ2 mm. Therefore, the structure in the present invention can be used to realize the placement of thin ropes.

[0040] Further, the remaining space in the inner cavity of the sheath 5 is filled with low-density solid glue, which has strong fluidity before curing and can fill the array at high speed. After curing, the density does not exceed 0.90 g / cm 3 , and the overall array realizes a zero-buoyancy design.

[0041] Through the above solution, the vibration isolation and reduction module is finally formed into an array, whose density meets the zero buoyancy requirement of seawater, and the diameter ranges from 15.50 mm to 15.99 mm.

[0042] The assembly process of the present invention:

[0043] During assembly, the cylindrical platform 14 of the load-bearing member 2 is embedded into the corresponding array connector 1, pressed tightly by the compression ring 8, and fixed by screws to prevent rotation, thereby achieving tensile resistance and fixation. A sheath 5 is installed between two load-bearing members 2, and a number of load-bearing skeletons 4 are arranged at equal intervals along the axial direction of the inner cavity of the sheath 5 to support the sheath 5. One end of the elastic rope 7 is fixed to one of the load-bearing members 2 through the elastic rope hole 10, and the other end of the elastic rope 7 sequentially passes through each load-bearing skeleton 4 (elastic rope hole 10) and then is fixed to the elastic rope hole 10 of the other load-bearing member 2. The load-bearing rope 3 is divided into two strands and passes out from the load-bearing rope hole 9 of one of the load-bearing members 2. After arranging the wire along the outer wall (load-bearing rope laying groove 11) of each load-bearing skeleton 4, it passes into the load-bearing rope hole 9 of the other load-bearing member 2 and is combined into one strand. The flexible optical cable 6 is arranged along the outer wall (flexible optical cable installation groove 13) of each load-bearing skeleton 4, and both ends of the flexible optical cable 6 are respectively connected to the corresponding array connector 1. After the wire laying and placement are completed, the remaining space in the inner cavity of the sheath 5 is filled with low-density solid glue, and finally the vibration isolation and reduction module is formed into an array, whose density meets the zero buoyancy requirement of seawater, and the diameter ranges from 15.50 mm to 15.99 mm (i.e., less than 16 mm).

[0044] By adopting materials such as flexible optical cables, low-density polyurethane glue, and low-density skeletons, and designing an ultra-fine elastic rope threading structure, an ultra-fine cable core threading through the sheath and a glue filling structure, the present invention provides an ultra-fine diameter fiber towed array vibration isolation and reduction module with a diameter not exceeding 16 mm, realizing the ultra-small design of the fiber towed line array sonar and meeting the limited requirements of the load capacity of the underwater acoustic sensing unmanned platform.

[0045] Through miniaturized structural design, adopting high-strength array connectors, load-bearing members, elastic ropes, load-bearing ropes, low-density skeletons, flexible optical cables, low-density solid glue, sheaths and other structures, and proposing an elastic rope hot cutting threading structure, an ultra-fine wire array threading through the sheath structure, and an ultra-fine wire array glue filling structure, the present invention solves the problems in the realization of related processes, realizes zero buoyancy trimming of the entire array, completes the development of an array with a diameter of Φ16 mm and a low-speed towing test on the lake, successfully accumulates engineering experience, and has important application value in the field of underwater acoustic sensing.

[0046] It can be understood that for those skilled in the art, equivalent replacement or change of the technical solutions and inventive concepts of the present invention should fall within the protection scope of the appended claims of the present invention.

Claims

1. An ultra-fine diameter optical fiber towed array vibration reduction and isolation module, characterized in that: include: Two array connectors (1) are respectively arranged at two ends of the vibration isolation module, and a sheath (5) is installed between the two array connectors (1); Two load-bearing members (2) are fixedly mounted on the corresponding array connector (1), the other end of the load-bearing member (2) extends into the sheath (5) and is provided with a load-bearing rope hole (9) and an elastic rope hole (10); A plurality of load-bearing frames (4) are arranged at equal intervals along the axial direction of the inner cavity of the sheath (5) to support the sheath (5); An elastic rope (7) is inserted into the sheath (5), one end of which is fixed to a load-bearing member (2) through an elastic rope hole (10), and the other end of which passes through each load-bearing frame (4) in sequence and is then fixed to the elastic rope hole (10) of another load-bearing member (2); A load-bearing rope (3) is inserted into the sheath (5), the load-bearing rope (3) is divided into two strands, passes through the load-bearing rope hole (9) of one load-bearing member (2), is arranged along the outer wall of each load-bearing frame (4), passes through the load-bearing rope hole (9) of another load-bearing member (2) and merges into one strand; and The flexible optical cable (6) is inserted into the sheath (5) and arranged along the outer wall of each load-bearing frame (4), and both ends of the flexible optical cable (6) are respectively connected to the corresponding array connectors (1).

2. The ultra-fine fiber towed array vibration reduction and isolation module according to claim 1, characterized in that: A cylindrical platform (14) is provided at one end of the load-bearing member (2) fixed to the array connector (1); the cylindrical platform (14) is embedded in the array connector (1) and is fixed by being compressed by a pressure ring (8).

3. The ultra-fine fiber towed array vibration reduction and isolation module according to claim 1, characterized in that: Each load-bearing frame (4) is provided with an elastic rope threading hole (12) at its center for the elastic rope (7) to pass through, and load-bearing rope laying grooves (11) are symmetrically provided on both sides of the outer wall of the load-bearing frame (4) for laying and routing the load-bearing rope (3). A plurality of flexible optical cable installation grooves (13) are evenly distributed on the outer wall of the load-bearing frame (4) between the two load-bearing rope laying grooves (11) for laying and routing the flexible optical cable (6).

4. The ultra-fine fiber towed array vibration reduction and isolation module according to claim 1, characterized in that: The load-bearing frame (4) is made of glass microbead material.

5. The ultra-fine fiber towed array vibration reduction and isolation module according to claim 1, characterized in that: The array connector (1) and the load-bearing member (2) are made of TC4 titanium alloy material and have a tensile strength of not less than 895 MPa and a specified residual elongation stress of not less than 830 MPa.

6. The ultra-fine fiber towed array vibration reduction and isolation module according to claim 1, characterized in that: The load-bearing rope (3) is a flat wear-resistant rope with a breaking resistance of not less than 150 kg.

7. The ultra-fine fiber towed array vibration reduction and isolation module according to claim 1, characterized in that: The sheath (5) is made of PU material and is made into a tubular structure, and its outer diameter does not exceed Φ15 mm.

8. The ultra-fine fiber towed array vibration reduction and isolation module according to claim 1, characterized in that: The inner cavity of the sheath (5) is filled with low-density solid glue, and the density after curing does not exceed 0.90g / cm 3 .

9. The ultra-fine fiber towed array vibration reduction and isolation module according to claim 1, characterized in that: The flexible optical cable (6) adopts a Teflon-coated metal flexible armor tube, and a pair of thin-diameter micro-bend-resistant optical fibers are arranged in the flexible optical cable (6).

10. The ultra-fine fiber towed array vibration reduction and isolation module according to claim 1, characterized in that: The elastic rope (7) is an ultra-fine single-braided nylon rope with a diameter of Φ2mm, and the elongation at a low towing speed does not exceed 15%.

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