Ship cargo hold structure and verification method thereof

Abstract

The ship cargo hold structure comprises a cargo hold, a following device is arranged in the cargo hold, an ultrasonic detector is fixedly installed on a fixing part of the following device, a wireless signal receiving device is arranged in the cargo hold, a wireless signal receiving and transmitting device is arranged on the ultrasonic detector, and a wireless signal receiving and transmitting device is arranged on the wireless signal receiving and transmitting device. A data storage unit is arranged on the following device and used for storing detection data of the ultrasonic detector, a data processing terminal is arranged on the outer side of the cargo hold, and the data processing terminal is connected with the wireless signal receiving and transmitting device and the wireless signal receiving device through radio signals. The data processing terminal is used for processing data detected by the ultrasonic detector, and the ultrasonic detector can be driven by the following device to move to any position in the cargo hold, so that accurate data of the position is acquired through the ultrasonic detector, and detection of the structure in the cargo hold and acquisition of detection data are realized.

Description

Technical Field

[0001] The present invention relates to the technical field of ship welding data processing, and particularly relates to a ship cargo hold structure and a verification method thereof. Background Art

[0002] Wear-resistant steel is a special performance steel used in wear conditions. Its main characteristics are high strength, hardness and wear resistance, and it is mainly applied to working conditions with a certain impact load. The domestic and foreign research on wear-resistant steel mainly focuses on the basic research of the mechanical properties of the material, the influencing factors of the ultimate strength and the influencing mechanism. In the ship field, there is a small amount of application on polar ships, while there are basically no application examples on civilian ships and engineering ships. The 20,000 DWT transshipment barge is mainly used for transporting iron ore. The conventional design is that the cargo hold uses high-strength steel with an allowable stress of 355 MPa, and then a polymer material is installed on the surface. The ship sails on the sea for a long time and bears the alternating stress caused by waves. The polymer material is easily damaged and the cost is relatively high. Therefore, the overall longitudinal strength problem is the biggest problem in the use of wear-resistant steel. By referring to road transportation, the cargo hold is designed with wear-resistant steel.

[0003] China Shipbuilding Industry Corporation has successfully applied the steel-ceramic composite material by introducing it into bulk carriers for transporting coal and ore. Especially in the "bulk carrier" designed and manufactured by it, the steel-ceramic composite material is applied to the interior of the cargo hold and the hull surface, which can withstand the long-term friction of heavy objects such as ore and coal, so as to improve wear resistance and extend the service life of the hull, and at the same time reduce the maintenance frequency; China COSCO Shipping uses HARDOX steel plates in the cargo hold design of its ore and coal transport ships, mainly to improve the wear resistance of the cargo hold and reduce the wear caused by the friction of ore or coal. During the operation of these ships, they bear long-term and heavy-load transportation work. The application of HARDOX steel plates has greatly improved their structural durability and reduced the maintenance cost.

[0004] The above prior art solutions have the following defects: Although polymer materials have certain wear resistance, they are prone to wear when enduring the friction and impact of heavy objects such as ores and coals for a long time. Especially in the case of fluctuations, large impact forces, and high abrasive strength of materials during transportation, the surface is prone to peeling or cracking, resulting in a rapid decline in wear resistance; when exposed to the marine environment or extreme temperatures for a long time, the performance of polymer materials will be greatly affected, and aging, embrittlement, or corrosion phenomena are likely to occur, reducing their wear resistance and service life; Polymer materials (such as polyurethane, polyethylene, etc.) are usually relatively expensive. Especially during the large-scale shipbuilding process, covering the large surface area of the cargo hold increases the material procurement and construction costs; Due to the easy damage of polymer materials, regular maintenance and replacement are required during ship operation, increasing the total cost of ship operation. Especially when operating in a harsh environment for a long time, the maintenance costs of these materials will accumulate rapidly; Environmental pollution problem: Some polymer materials (such as polyurethane, polyethylene, etc.) may not be completely degraded after damage and remain in the environment for a long time, causing negative impacts on the ecosystem. Especially during the high-frequency replacement and repair processes, the waste treatment problem may also pose a certain pressure on the environment.

[0005] Therefore, it is particularly important to use high-strength steel (AQ98) as the main structure of the cargo hold and ensure stable quality when welding each module. Summary of the Invention

[0006] The purpose of the present invention is to provide a ship cargo hold structure and its verification method to solve the problems existing in the above prior art.

[0007] The above technical objectives of the present invention are achieved through the following technical solutions:

[0008] A ship cargo hold structure includes a cargo hold. A following device is arranged inside the cargo hold. The following device includes a fixed part and a moving part. An ultrasonic detector is fixedly installed on the moving part. A plurality of wireless signal receiving devices are arranged inside the cargo hold. A wireless signal transceiver is arranged on the ultrasonic detector. The wireless signal transceiver of the ultrasonic detector is in radio signal connection with the wireless signal receiving devices. A data storage unit is arranged on the following device. The data storage unit is used to store the detection data of the ultrasonic detector. A data processing terminal is arranged outside the cargo hold. The data processing terminal is in radio signal connection with both the wireless signal transceiver and the wireless signal receiving devices. The data processing terminal is used to process the data detected by the ultrasonic detector.

[0009] By adopting the above technical solutions, the ultrasonic detector can be moved to any position inside the cargo hold under the drive of the following device, so as to obtain accurate data at this position through the ultrasonic detector, realize the detection of the internal structure of the cargo hold and the acquisition of detection data, facilitate the analysis of the safety of the cargo hold structure, and can obtain the latest data information in real time when needed, avoiding the waste of man-hours caused by unqualified processes.

[0010] In a further embodiment, the following device includes:

[0011] Fixed frames arranged on both inner sides of the cargo hold, and the two fixed frames are symmetrically arranged about the central axis of the cargo hold. A drive module is arranged on each fixed frame;

[0012] A cross beam, both ends of the cross beam are fixedly connected to the drive modules on the two fixed frames respectively. The drive module is used to synchronously drive the cross beam to move circumferentially along the fixed frame. A linear drive device is arranged on the cross beam, and the ultrasonic detector is fixedly connected to the linear drive device through an automatic telescopic rod.

[0013] By adopting the above technical solutions, the coordinated work of the remote control drive module, the linear drive device and the automatic telescopic rod can realize the position adjustment of the ultrasonic detector.

[0014] In a further embodiment, a visual monitoring unit is arranged inside the cargo hold. The visual monitoring unit includes a camera and a fill light. The camera is fixedly installed on the inner top of the cargo hold. A plurality of laser range sensors are arranged on the cross beam, and a temperature sensor is arranged on the automatic telescopic rod. The temperature sensor is used to obtain the ambient temperature around the end of the automatic telescopic rod where the ultrasonic detector is installed. The laser range sensor is used to cooperate with the visual monitoring unit to obtain the position information of the personnel inside the cargo hold.

[0015] By adopting the above technical solutions, the automatic following device can perform automatic following according to the obtained personnel position information, avoiding manual control and making the device more intelligent.

[0016] The present invention also discloses a method for verifying the structure of a ship's cargo hold, including the following steps:

[0017] Step S1: Plan the welding path and set the starting welding point. Plan the welding path according to the structure of the ship's cargo hold, set the starting welding point, and set the welding speed;

[0018] Step S2: Device self-check. The following device performs self-check, and actually runs according to the welding path. Compare the actually run path with the planned welding path, and perform precision compensation on the deviation points;

[0019] Step S3, data acquisition: When the operator starts working, the following device, visual monitoring unit, temperature sensor, and laser ranging sensor are activated to obtain the visual image of the current welding position and the temperature of the welding point, so as to ensure that the ultrasonic detector can obtain the weld data along the welding path with a fixed time difference;

[0020] Step S4: Process the weld data, perform noise reduction on the acquired weld data, and analyze whether there is any unqualified welding problem. If so, issue an alarm; otherwise, continue to follow;

[0021] Step S5: Store, record and encrypt the historical data for preservation.

[0022] By adopting the above technical solution, the ultrasonic detector can acquire and process the data of the welding point in real time, so as to promptly discover welding problems and correct them, thereby greatly improving the welding quality of the weld.

[0023] In a further embodiment, step S3 further includes:

[0024] Step S31: Obtain the operator's position, mark the operator's position according to the image of the visual monitoring unit, determine whether the operator is in the operating area, and verify the operator's position through the temperature sensor. The conforming method is to determine whether the heat source is in the same position;

[0025] Step S32: Measure the operator's position and the relative position of the ultrasonic detector and the cargo hold. By measuring the relative position between the beam and the operator through a laser ranging sensor, the operator's position in the cargo hold can be known. By adding a laser ranging sensor to one end of the automatic telescopic rod where the ultrasonic detector is installed, the distance between the ultrasonic detector and the cargo hold bulkhead can be identified.

[0026] In a further embodiment, step S4 further includes:

[0027] Step S41: generating a density point cloud map according to the echo energy density;

[0028] Step S42: generating a contour color map according to the echo time;

[0029] Step S43: Check whether the echo time difference is within the preset warning value. If yes, no alarm is issued; otherwise, an alarm is issued.

[0030] Step S44: Compare the density point cloud map to determine whether the density decreases smoothly along the welding path. If so, no alarm is issued; otherwise, an alarm is issued.

[0031] In a further embodiment, the step S44 further includes:

[0032] Compare the point cloud density map, obtain the temperature of each area in the point cloud density map, and judge whether the area density exceeds the density range at this temperature according to the temperature. If so, an alarm is issued; if not, no alarm is issued.

[0033] In a further embodiment, the device self-check in step S2 further includes working current detection and working voltage detection.

[0034] In summary, the present invention has the following beneficial effects:

[0035] 1. Driven by the following device, the ultrasonic detector can move to any position inside the cargo hold, so as to obtain accurate data at this position through the ultrasonic detector, realize the detection of the internal structure of the cargo hold and the acquisition of detection data, facilitate the analysis of the safety of the cargo hold structure, and can obtain the latest data information in real time when needed, avoiding the waste of man-hours caused by unqualified processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is the overall structural schematic diagram of a ship's cargo hold structure of the present invention;

[0037] Figure 2 is the overall structural schematic diagram of a calibration method for a ship's cargo hold structure of the present invention;

[0038] Figure 3 is the schematic diagram of the echo energy density point cloud map of a calibration method for a ship's cargo hold structure of the present invention;

[0039] Figure 4 is the schematic diagram of the echo time contour color map of a calibration method for a ship's cargo hold structure of the present invention.

[0040] In the figure, 2 is the following device; 21 is the fixing frame; 22 is the cross beam; 3 is the ultrasonic detector; 4 is the driving module; 5 is the linear driving device; 6 is the automatic telescopic rod; 7 is the visual monitoring unit. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0041] The present invention will be further described in detail below with reference to the accompanying drawings.

[0042] Among them, the same parts are denoted by the same reference numerals. It should be noted that the terms "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to the attached Figure 1In the directions, the terms "bottom surface" and "top surface", "inner" and "outer" respectively refer to the directions towards or away from the geometric center of a specific component. In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of this specification, "a plurality of" means two or more unless otherwise specifically defined.

[0043] Embodiment 1:

[0044] As Figure 1 shown, a ship cargo hold structure and its calibration method include a cargo hold. A following device 2 is arranged inside the cargo hold. The following device 2 includes a fixed part and a moving part. An ultrasonic detector 3 is fixedly installed on the moving part. A plurality of wireless signal receiving devices are arranged inside the cargo hold. A wireless signal transceiver is arranged on the ultrasonic detector 3 (the operating frequency is adjustable from 2 to 10 MHz). The wireless signal transceiver of the ultrasonic detector 3 is radio-signal connected to the wireless signal receiving devices (a 5G / WiFi6 hybrid network). A data storage unit is arranged on the following device 2. The data storage unit is used to store the detection data of the ultrasonic detector 3. A data processing terminal is arranged outside the cargo hold. The data processing terminal is radio-signal connected to both the wireless signal transceiver and the wireless signal receiving devices. The data processing terminal is used to process the data detected by the ultrasonic detector 3. The following device 2 includes:

[0045] Fixed frames 21 arranged on both inner sides of the cargo hold, and the two fixed frames 21 are symmetrically arranged about the central axis of the cargo hold. A driving module 4 is arranged on each fixed frame 21. More precisely, when the length direction of the cargo hold is the left-right direction, a conforming fixed frame 21 is installed on both the left and right sides inside the cargo hold. Then, a crossbar for installation is arranged at the central position of the fixed frame 21. A driving module is installed at the central position of the crossbar. The driving module is a high-precision motor. Since this device is for a cargo hold with a hexagonal interior, only by fixedly connecting the crossbar to the output shaft of the high-precision motor can the high-precision motor make the movement trajectory of the crossbar present the shape of an inscribed circle to achieve the circumferential movement of the position of the crossbar. More precise position determination and movement need to be achieved through the mutual cooperation of a linear driving device 5 and an automatic telescopic rod 6 installed on the crossbar to finely adjust the position of the ultrasonic detector 3. In this embodiment, the automatic telescopic rod 6 uses an existing multi-axis robotic arm as long as it can achieve movement with more than three degrees of freedom;

[0046] The cross beam 22 has its two ends fixedly connected to the driving modules 4 on two fixing frames 21 respectively. The driving module 4 is used to synchronously drive the cross beam 22 to move circumferentially along the fixing frame 21. A linear driving device 5 is arranged on the cross beam 22, and the ultrasonic detector 3 is fixedly connected to the linear driving device 5 through the automatic telescopic rod 6;

[0047] A visual monitoring unit 7 is arranged inside the cargo hold. The visual monitoring unit 7 includes a camera and a fill light. The camera is fixedly installed on the inner top of the cargo hold. A plurality of laser range sensors are arranged on the cross beam 22, and a temperature sensor is arranged on the automatic telescopic rod 6. The temperature sensor is used to obtain the ambient temperature around the end of the automatic telescopic rod 6 where the ultrasonic detector 3 is installed. The laser range sensors are used to cooperate with the visual monitoring unit 7 to obtain the position information of the personnel inside the cargo hold.

[0048] In a further solution, two linear driving devices 5 can be arranged on the cross beam. One linear driving device 5 is used to drive the automatic telescopic rod 6 to move on the cross beam 22, and an automatic welding torch is installed on the other linear driving device 5. In this way, personnel operation can be completely avoided. After setting the parameters, automated and standardized welding can be realized, making the welding quality more stable.

[0049] When in use, because the temperature of the just-welded solder joints is relatively high, for the accuracy of the data, it is necessary to perform ultrasonic detection on the welded position through the automatic telescopic rod 6 (robotic arm) with a fixed time interval behind the welding position. This time is generally 5 - 10 seconds, and after a weld seam is completely welded, it is also necessary to drive the ultrasonic detector 3 to scan the weld seam again to obtain it.

[0050] As Figures 2 - 4 shown, a verification method for the structure of a ship's cargo hold includes the following steps:

[0051] Step S1: Plan the welding path and set the starting welding point. Plan the welding path according to the structure of the ship's cargo hold, set the starting welding point, and set the welding speed. Since the size of the ship's cargo hold determines how many steel plates are needed and how they are arranged, these arrangement methods determine the required welding path, and the welding speed is determined according to the thickness of the steel plates;

[0052] Step S2: Device self-check. Follow the device 2 to perform self-check, and perform actual operation according to the welding path. Compare the actual operation path with the planned welding path, and perform precision compensation on the deviation points. The device self-check in Step S2 also includes working current detection and working voltage detection.

[0053] Step S3, data acquisition: After the operator starts working, the following devices are activated: the following device 2, the visual monitoring unit 7, the temperature sensor, and the laser range finder sensor to obtain the visual image of the current welding position and the temperature of the welding point, so as to ensure that the ultrasonic detector 3 acquires the weld data on the welding path at a fixed time difference. Step S3 further includes: Step S31, obtaining the operator's position: According to the image of the visual monitoring unit 7, mark the operator's position, determine whether the operator is in the operation area, and verify the position of the person through the temperature sensor. The verification method is to determine whether the heat source center is at the same position. Step S32, measuring the relative positions of the operator's position, the ultrasonic detector 3 and the cargo hold: Measure the relative position between the cross beam 22 and the operator through the laser range finder sensor, and then the position of the operator in the cargo hold can be obtained. By adding a laser range finder sensor to one end of the automatic telescopic rod 6 where the ultrasonic detector 3 is installed, the distance between the ultrasonic detector 3 and the cargo hold bulkhead can be identified. The operator is mainly used to judge whether the equipment is operating according to the process requirements and set parameters during the initial operation stage of the equipment. Since the interior of the cargo hold will eventually be in a highly airtight environment, in order to avoid personal injury to personnel caused by VOC waste gas during welding, after the operator determines that the equipment is running, they will leave the site in time. To further ensure the safety of the operator, the visual monitoring unit 7 reminds the operator to leave the site after the equipment runs stably.

[0054] Step S4, processing weld data: Denoise the acquired weld data and analyze whether there will be welding problems with unqualified quality. If so, an alarm is issued; if not, continue to follow. It is necessary to first determine which features need to be extracted: echo energy density distribution (threshold: >80% of the benchmark is abnormal), time difference of flight (tolerance: ±0.5 μs), dispersion characteristic analysis (FFT transform, 512-point window), deep learning criterion: training the ResNet-34 network (input: 256×256 time-frequency diagram). Step S4 further includes:

[0055] Step S41, generating a density point cloud map according to the echo energy density;

[0056] Step S42, generating a contour color map according to the echo time;

[0057] Step S43, comparing whether the echo time difference is within the preset warning value. If so, no alarm is issued; if not, an alarm is issued;

[0058] Step S44, comparing the density point cloud map and judging whether the density smoothly decreases along the welding path direction. If so, no alarm is issued; if not, an alarm is issued. Step S44 also includes:

[0059] Compare the point cloud density map, obtain the temperature of each region in the point cloud density map, and judge whether the regional density exceeds the density range at this temperature according to the temperature. If so, an alarm is issued; if not, no alarm is issued. The method for detecting the point cloud density is to connect the points with the same energy density. Suppose the set warning energy density is 15 DB, then the density lines greater than or equal to 15 DB are selected. If the time span of these lines is greater than or equal to 10 S, an alarm is issued. The time span indicates that this energy density exists for a long time, excluding misjudgment. When there are internal cracks or voids in the weld, the echo energy will be significantly stronger than that in the region without internal cracks.

[0060] Step S5: Store, record, and encrypt and preserve the historical data.

[0061] In summary: Due to its excellent wear resistance and impact resistance, the loss and wear rate of the cargo hold of AQ98 steel is greatly reduced. Even under extreme transportation conditions, the structural integrity of AQ98 steel can be maintained for a long time, reducing the number of times of ship downtime for maintenance during navigation and ensuring the continuity and efficiency of transportation. When AQ98 steel faces the friction and impact of heavy cargo such as ore and coal, it is less likely to have damages such as cracks and peeling. Therefore, the maintenance frequency of the ship's cargo hold is greatly reduced. During the operation of the ship, the maintenance and inspection costs of the steel are relatively low, which helps to reduce the operation costs. The above technical solution can be used to perform real-time quality detection on the welded joints to ensure that the welding quality meets the standards required by the process and realize the replacement of the steel in the cargo hold.

[0062] In the embodiments disclosed in the present invention, terms such as "installation", "connection", "attachment", and "fixation" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; "attachment" can be a direct attachment or an indirect attachment through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments disclosed in the present invention can be understood according to specific circumstances.

[0063] This specific embodiment is only an explanation of the present invention and does not limit the present invention. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as it is within the scope of the claims of the present invention, it is protected by the patent law.

Claims

1. A ship cargo hold structure, characterized in that: It includes a cargo hold, in which a following device (2) is provided. The following device (2) includes a fixed part and a moving part. An ultrasonic detector (3) is fixedly installed on the moving part. A plurality of wireless signal receiving devices are arranged inside the cargo hold. A wireless signal transceiver is provided on the ultrasonic detector (3). The wireless signal transceiver of the ultrasonic detector (3) is in radio signal connection with the wireless signal receiving devices. A data storage unit is provided on the following device (2), and the data storage unit is used to store the detection data of the ultrasonic detector (3). A data processing terminal is arranged outside the cargo hold. The data processing terminal is in radio signal connection with both the wireless signal transceiver and the wireless signal receiving devices. The data processing terminal is used to process the data detected by the ultrasonic detector (3).

2. A ship cargo hold structure and calibration method thereof according to claim 1, characterized in that: The following device (2) includes: Fixed frames (21) arranged on both sides inside the cargo hold, and the two fixed frames (21) are symmetrically arranged about the central axis of the cargo hold. A driving module (4) is arranged on each fixed frame (21); A cross beam (22), both ends of the cross beam (22) are fixedly connected to the driving modules (4) on the two fixed frames (21) respectively. The driving module (4) is used to synchronously drive the cross beam (22) to move along the circumferential direction of the fixed frame (21). A linear driving device (5) is arranged on the cross beam (22). The ultrasonic detector (3) is fixedly connected to the linear driving device (5) through a telescopic rod (6).

3. A ship cargo hold structure and its verification method according to claim 2, characterized in that: A visual monitoring unit (7) is arranged inside the cargo hold. The visual monitoring unit (7) includes a camera and a fill light. The camera is fixedly installed on the inner top of the cargo hold. A plurality of laser range sensors are arranged on the cross beam (22). A temperature sensor is arranged on the telescopic rod (6). The temperature sensor is used to obtain the ambient temperature around the end of the telescopic rod (6) where the ultrasonic detector (3) is installed. The laser range sensors are used to cooperate with the visual monitoring unit (7) to obtain the position information of the personnel inside the cargo hold.

4. A verification method for the ship's cargo hold structure according to any one of claims 1-3, characterized in that, It includes the following steps: Step S1: Plan the welding path and set the starting welding point. Plan the welding path according to the structure of the ship's cargo hold, set the starting welding point, and set the welding speed; Step S2: Device self-check. The following device (2) conducts self-check, and actually operates according to the welding path, compares the actually operated path with the planned welding path, and compensates the accuracy of the deviation; Step S3: Data acquisition. After the operator starts working, start the following device (2), the visual monitoring unit (7), the temperature sensor, and the laser range sensors to obtain the visual image of the current welding position and the temperature of the welding point, so as to ensure that the ultrasonic detector (3) obtains the weld data on the welding path at a fixed time difference; Step S4: Process the weld data. Denoise the obtained weld data, and analyze whether there will be welding problems with unqualified quality. If so, issue an alarm; if not, continue to follow; Step S5: Store, record, and encrypt and preserve the historical data.

5. The verification method of the ship's cargo hold structure according to claim 4, characterized in that The step S3 further includes: Step S31: Obtain the operator's position, mark the operator's position according to the image of the visual monitoring unit (7), determine whether the operator is in the operation area, and verify the operator's position through the temperature sensor. The verification method is to determine whether the heat sources are at the same position. Step S32: Measure the position of the operator and the relative position between the ultrasonic detector (3) and the cargo hold. Measure the relative position between the crossbeam (22) and the operator through the laser range finder sensor, and then the position of the operator in the cargo hold can be obtained. By adding a laser range finder sensor to one end of the automatic telescopic rod (6) where the ultrasonic detector (3) is installed, the distance between the ultrasonic detector (3) and the cargo hold bulkhead can be identified.

6. The verification method for the ship's cargo hold structure according to claim 4, characterized in that, Step S4 further includes: Step S41: Generate a density point cloud map according to the echo energy density. Step S42: Generate a contour color map according to the echo time. Step S43: Compare whether the echo time difference is within the preset warning value. If so, no alarm is issued; otherwise, an alarm is issued. Step S44: Compare the density point cloud map and determine whether the density decreases smoothly along the welding path direction. If so, no alarm is issued; otherwise, an alarm is issued.

7. The verification method of the ship's cargo hold structure according to claim 6, characterized in that Step S44 further includes: Compare the point cloud density map, obtain the temperature of each area in the point cloud density map, and determine whether the area density exceeds the density range at this temperature according to the temperature. If so, an alarm is issued; otherwise, no alarm is issued.

8. A verification method for a ship cargo hold structure according to claim 4, characterized in that: The device self-check in Step S2 further includes working current detection and working voltage detection.

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