A system, method and apparatus for analyzing a weld joint impact fracture based on dot matrix laser scanning quantification

Abstract

The application discloses a kind of based on dot matrix laser scanning quantization welded joint impact fracture analysis system, method and device, and it is related to welding detection technical field.Solve the problem that existing impact toughness test evaluation method is influenced by model simplification, boundary condition setting and other factors, can only qualitative evaluation welded joint fracture mechanism in actual application.Analysis system includes: fracture sample clamping end, dot matrix laser emission and receiving system, motion platform, control and data processing system;Dot matrix laser emission and receiving system are composed of n dot matrix laser emitter and corresponding ranging receiving sensor unit;Motion platform and for dot matrix laser emission and receiving system one-dimensional direction horizontal motion;Fracture sample clamping end is used to fix the impact fracture sample of welded joint;Control and data processing system are used to control the dot matrix laser emission time sequence of n units and calculate the distance data of n position coordinate points.The application realizes the quantitative evaluation analysis of welded joint impact fracture.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of welding detection, in particular to a test method for quantitatively evaluating the impact toughness of a welded joint. BACKGROUND

[0002] Welding is a widely used connection technology in various engineering fields, especially in shipbuilding industry, steel structure construction industry and heavy equipment industry, etc. The quality of the welded joint directly affects the safety and durability of the entire structure. Therefore, it is crucial to effectively evaluate the performance of the welded joint. Impact toughness refers to the resistance of a material to impact loading. For a welded joint, its impact toughness is directly related to its behavior under dynamic loading, such as resistance to fatigue, brittle fracture, etc. Therefore, it is extremely necessary to evaluate and test the impact toughness of the welded joint.

[0003] Due to various defects generated during welding, uneven heat affected distribution and complex material thermal properties, the performance of the welded joint is often difficult to predict and control. Therefore, studying the evaluation and testing method of the impact toughness of the welded joint has important practical significance for improving the performance of the welded joint and ensuring the safety and durability of the structure.

[0004] Commonly used test methods for evaluating the impact toughness of the welded joint include drop hammer impact test, charpy impact test and bending impact test, etc. These methods have the intuitive feature of quantitatively evaluating the impact toughness of the welded joint by simulating the impact loading under actual working conditions, which can reflect the actual performance of the welded joint to some extent. However, these methods also have some limitations, such as long test period, high cost, and susceptibility to human factors, etc. With the continuous development of computer technology, numerical simulation methods have been widely applied in the evaluation of the impact toughness of the welded joint.

[0005] Numerical simulation method establishes a three-dimensional model of the welded joint to simulate the stress distribution, strain evolution and fracture process under impact loading. This method has the advantages of low cost, short period, high repeatability, etc. However, the accuracy of numerical simulation method is affected by factors such as model simplification and boundary condition setting, which needs to be verified and corrected combined with experimental data, so its application in practical application is very limited. And there is a certain difference between the mechanical dial reading and the computer reading, the human factor is large, when the data transmission problem occurs, the test data will be lost and cannot be retrieved, the test will fail, the sample needs to be prepared again, and the test needs to be carried out again, which leads to the increase of test cost and causes great waste. SUMMARY

[0006] The present application aims at the problem that the existing impact toughness test evaluation method is influenced by model simplification, boundary condition setting and other factors, and can only qualitatively evaluate the fracture mechanism of the welded joint in actual application, and proposes a welded joint impact fracture analysis system based on dot matrix laser scanning quantization, which comprises:

[0007] A fracture sample clamping end, a dot matrix laser emission and receiving system, a motion platform, a control and data processing system;

[0008] The dot matrix laser emission and receiving system is composed of n vertically distributed dot matrix laser emitters and corresponding ranging receiving sensor units, and one dot matrix laser emitter and corresponding ranging receiving sensor is one laser emission and receiving unit.

[0009] Each unit in the dot matrix laser emission and receiving system is used for separately emitting pulsed laser with a preset frequency, and the pulsed laser is reflected back to the corresponding ranging receiving sensor of each unit after horizontally irradiating the front impact fracture.

[0010] The motion platform is connected with the dot matrix laser emission and receiving system, and is used for realizing one-dimensional horizontal motion of the dot matrix laser emission and receiving system.

[0011] The fracture sample clamping end is used for fixing the impact fracture sample of the welded joint, and the fracture side faces the dot matrix laser emitter.

[0012] The control and data processing system is used for controlling the time sequence of the dot matrix laser emission of the n units and calculating the distance data of the n position coordinate points.

[0013] Further, a preferred mode is also proposed, in which the light core diameter of the dot matrix laser emitter is 0.05mm, and the ranging receiving sensor accuracy is 0.005mm.

[0014] Further, a preferred mode is also proposed, in which n is 100.

[0015] Further, a preferred mode is also proposed, in which the 100 laser emission and receiving units are sequentially recorded from bottom to top as D1 (0，0) , D2 (0，1) , …, D100 (0，99) , wherein D is the unit number, (a, b) is the coordinate position, D1 (0，0) unit and D100 (0，99) unit vertical distance total length is set to 8mm, and the 100 laser emission and receiving units are uniformly distributed on the dot matrix laser emission and receiving system.

[0016] Further, a preferred mode is also proposed, in which the method for controlling the laser emission time sequence is as follows:

[0017] The PIN photodiode is used in combination with a DG645 fast delay pulse transmitter to realize the transmission of the laser signal.

[0018] The rising edge response time of the PIN photodiode is in the order of nanoseconds, which is used to convert the optical signal into an electrical signal, and then the electrical delay of the DG645 is used to control the synchronization of the photoelectric signal.

[0019] Based on the same inventive concept, the application also provides a welded joint impact fracture analysis method based on dot matrix laser scanning quantization, which comprises the following steps:

[0020] The pulse frequency of the laser emission unit and the motion speed of the platform are set, and the dot matrix laser emission and receiving system and the motion platform are started;

[0021] D1 (0，0) After the unit first emits laser and receives the reflected laser signal, the laser irradiates the impact fracture and is reflected back to the ranging receiving sensor of the unit, and after receiving the reflected laser signal, D2 (0，1) The unit continues to emit pulsed laser, and so on until D100 (0，99) After receiving the reflected laser signal corresponding to the position coordinate point, all data collection is completed;

[0022] With the horizontal movement of the motion platform, when the motion platform reaches the next preset position, D1 (1，0) The coordinate position fracture distance data is recorded, and the process is sequentially completed until D100 (99，99) Data collection is completed;

[0023] The collected data is processed by using a control and data processing system to obtain a plane fitting plane;

[0024] The relative convex-concave value of the impact fracture is calculated according to the fitting plane;

[0025] The impact toughness of the welded joint is evaluated according to the relative convex-concave value of the impact fracture.

[0026] Further, an optimal mode is further provided, wherein the pulse frequency of the single laser emission unit is set to 1 Hz, and the motion speed of the platform is set to 1 mm / s.

[0027] Further, an optimal mode is further provided, wherein the relative convex-concave value of the impact fracture is calculated according to the fitting plane, which comprises:

[0028]

[0029] Wherein, H is the relative convex-concave value of the impact fracture; S1 to S i are distance information; is a fitting plane.

[0030] Further, a preferred mode is proposed, which evaluates the impact toughness of the welded joint according to the relative convex-concave value of the impact fracture, comprising:

[0031] The greater the relative convex-concave value of the impact fracture, the more the fracture form of the welded joint tends to be ductile fracture, that is, the better the toughness of the welded joint;

[0032] The smaller the relative convex-concave value of the impact fracture, the more the fracture form of the welded joint tends to be brittle fracture, that is, the worse the toughness of the welded joint.

[0033] Based on the same inventive concept, the present application also proposes a welded joint impact fracture analysis device based on dot matrix laser scanning quantization, which comprises:

[0034] A frequency and speed setting unit is used to set the pulse frequency of the single laser emitting unit and the platform motion speed, and start the dot matrix laser emitting and receiving system and the motion platform;

[0035] A data acquisition unit is used to D1 (0，0) After the unit first emits laser and receives the reflected laser signal, the laser irradiated to the impact fracture is reflected back to the ranging receiving sensor of the unit, and after receiving the reflected laser signal, D2 (0，1) The unit will continue to emit pulsed laser, and so on until D100 (0，99) After receiving the reflected laser signal corresponding to the position coordinate point, all data acquisition is completed;

[0036] A horizontal moving unit is used for horizontal movement of the motion platform, and when the motion platform reaches the next preset position, D1 (1，0) Only then will the coordinate position fracture distance data be recorded, and the process will be repeated until D100 (99，99) Data collection is completed.

[0037] The present application has the advantages of:

[0038] The present application solves the problem that the existing impact toughness test evaluation method is affected by model simplification, boundary condition setting and other factors, and can only qualitatively evaluate the fracture mechanism of the welded joint in actual application.

[0039] The system can quantitatively and accurately obtain the geometric shape and size information of the impact fracture of the welded joint by designing a dot matrix laser emission and receiving system, and improves the analysis accuracy and repeatability. The system uses laser scanning technology, and does not need to directly contact the impact fracture of the welded joint, thereby avoiding secondary damage to the sample and reducing the influence of the test process on the surface state of the sample. Compared with the traditional test experiment, the test process of the system is faster, and time and resource costs are saved. The control and data processing system can quickly process a large amount of dot matrix laser scanning data, extract key information, and provide convenience for subsequent analysis and evaluation.

[0040] The analysis system disclosed by the application is based on dot matrix laser scanning technology, and obtains the shape and size information of the impact fracture of the welded joint by emitting pulse laser of a preset frequency and measuring the time of reflection back to the sensor. The main steps include: using n vertically distributed dot matrix laser emitters and corresponding distance measuring receiving sensor units to form a system, each unit emits pulse laser and receives the reflected signal. The motion platform is connected with the dot matrix laser system, so that the laser scanning system can move horizontally in one direction, thereby covering the entire impact fracture of the welded joint. The control and data processing system is responsible for controlling the time sequence of laser emission, and calculating the time delay of the reflected signal received by each dot matrix laser unit, so as to calculate the distance data of the corresponding points. The obtained distance data can be used to calculate the relative convex-concave value of the impact fracture, further analyze the fracture properties of the impact fracture of the welded joint, and evaluate the impact toughness of the welded joint.

[0041] The analysis system based on dot matrix laser scanning quantization of the welded joint impact fracture disclosed by the application solves the limitations caused by factors such as model simplification and boundary condition setting in the traditional welded joint impact toughness test method. By using advanced dot matrix laser scanning technology, quantitative analysis of the impact fracture of the welded joint is realized, the accuracy and efficiency of the test are improved, and more reliable data support is provided for performance evaluation of the welded joint. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 The schematic diagram of the analysis system based on dot matrix laser scanning quantization of the welded joint impact fracture is shown in the first embodiment, 1 is a fracture clamping end, 2 is an impact fracture sample, 3 is a dot matrix laser emission and receiving system, 4 is a single emission and receiving unit, 5 is a motion platform, 6 is a controller, and 7 is an upper computer.

[0043] Figure 2 The schematic diagram of the size specification of the titanium alloy welded joint V-shaped notch impact sample is shown in the eleventh embodiment. DETAILED DESCRIPTION

[0044] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application.

[0045] Embodiment one, see Figure 1 This embodiment is described. A welded joint impact fracture analysis system based on dot matrix laser scanning quantification, the analysis system comprises:

[0046] Fracture sample clamping end 1, dot matrix laser emission and receiving system 3, motion platform 5, control and data processing system;

[0047] The dot matrix laser emission and receiving system 3 is composed of n vertically distributed dot matrix laser emitters and corresponding ranging receiving sensor units. One dot matrix laser emitter and the corresponding ranging receiving sensor form one laser emission and receiving unit.

[0048] Each unit in the dot matrix laser emission and receiving system is used to emit pulsed laser with a preset frequency. The pulsed laser is reflected back to the corresponding ranging receiving sensor of each unit after irradiating the front impact fracture horizontally.

[0049] The motion platform 5 is connected with the dot matrix laser emission and receiving system 3, which is used to realize one-dimensional horizontal motion of the dot matrix laser emission and receiving system.

[0050] The fracture sample clamping end 1 is used to fix the impact fracture sample of the welded joint, and the fracture side faces the dot matrix laser emitter.

[0051] The control and data processing system is used to control the time sequence of dot matrix laser emission of n units and calculate the distance data of n position coordinate points.

[0052] The embodiment designs a dot matrix laser emission and receiving system, which can quantitatively obtain the geometric shape and size information of the impact fracture of the welded joint, and improves the analysis accuracy and repeatability. The system uses laser scanning technology, which does not need to directly contact the impact fracture of the welded joint, avoids secondary damage to the sample, and also reduces the influence of the test process on the sample. Compared with the traditional test, the test process of this system is faster, which saves time and resource cost. The control and data processing system can quickly process a large amount of dot matrix laser scanning data and extract key information, which provides convenience for subsequent analysis and evaluation.

[0053] The analysis system of the embodiment obtains the shape and size information of the impact fracture of the welded joint by emitting pulsed laser with a preset frequency and measuring the time of its reflection back to the sensor based on dot matrix laser scanning technology. The main steps include:

[0054] The system is composed of n vertically distributed point laser emitters and corresponding ranging receiving sensor units, each unit emits pulsed laser and receives reflected signals. The motion platform is connected with the point laser system, which enables the laser scanning system to move horizontally in one-dimensional direction, thereby covering the entire impact fracture of the welded joint. The control and data processing system is responsible for controlling the time sequence of laser emission and calculating the time delay of the reflected signals received by each point laser unit, thereby calculating the distance data of the corresponding points. The obtained distance data can be used to calculate the relative convex-concave value of the known impact fracture, further analyze the fracture properties of the impact fracture of the welded joint, and evaluate the impact toughness of the welded joint.

[0055] The system described in this embodiment solves the limitations caused by model simplification, boundary condition setting and other factors in traditional welded joint impact toughness test methods. By using advanced point laser scanning technology, quantitative analysis of the impact fracture of the welded joint is realized, the precision and efficiency of the test are improved, and more reliable data support is provided for the performance evaluation of the welded joint.

[0056] Embodiment two, this embodiment is a further limitation of the welded joint impact fracture analysis system based on point laser scanning quantification described in embodiment one, the point laser emitter optical core diameter is 0.05mm, and the ranging receiving sensor accuracy is 0.005mm.

[0057] In this embodiment, point laser emitters with an optical core diameter of 0.05mm and ranging receiving sensors with an accuracy of 0.005mm are used, which can realize high-precision quantitative analysis of the impact fracture of the welded joint and improve the accuracy of the data. Due to the small optical core diameter and high accuracy of the laser emitters and ranging sensors, the point laser emission and receiving system can capture more detailed impact fracture shape and size information, further improving the resolution of the analysis. Due to the high accuracy of the point laser emission and receiving system, it can more easily detect small defects or cracks in the impact fracture of the welded joint, which helps to discover potential welding quality problems as soon as possible.

[0058] The dot laser emitter with an optical core diameter of 0.05 mm is used to emit a fine laser beam, while the ranging receiving sensor with an accuracy of 0.005 mm is used to receive the reflected signal and measure the distance to the target. The combination of the two achieves high-precision scanning and measurement of the impact fracture of the welded joint. Through the high precision of the laser emitter and the ranging sensor, the dot laser emission and receiving system can select and record key data points of the impact fracture of the welded joint, such as size, shape, cracks, etc. These data points can provide a comprehensive evaluation of the impact toughness of the welded joint. By using a dot laser emitter with an optical core diameter of 0.05 mm and a ranging receiving sensor with an accuracy of 0.005 mm, the precision of the welded joint impact fracture analysis system is improved, which can more accurately quantify and analyze the impact toughness of the welded joint. Through fine data selection and high-precision measurement, this embodiment aims to enhance the system's ability to detect small defects in the impact fracture of the welded joint, which helps to detect potential welding quality problems in advance and improve the reliability and safety of the welded joint.

[0059] Embodiment three, this embodiment is a further limitation of the welded joint impact fracture analysis system based on dot laser scanning quantification according to embodiment one, wherein n is 100.

[0060] By setting the number of laser emission and receiving units n to 100, this embodiment can more comprehensively collect data of the impact fracture of the welded joint, covering more areas, thereby providing more detailed analysis results. Based on more sampling points, more accurate statistical analysis can be performed, including mean, standard deviation, distribution, etc., which helps to more comprehensively understand the characteristics and performance of the impact fracture of the welded joint. By setting the number of sampling points, the bias caused by insufficient sampling points can be reduced, the reliability of the results is improved, and the evaluation of the characteristics of the impact fracture of the welded joint is more reliable.

[0061] Embodiment four, this embodiment is a further limitation of the welded joint impact fracture analysis system based on dot laser scanning quantification according to embodiment three, wherein the 100 laser emission and receiving units are sequentially numbered from bottom to top as D1 (0，0) , D2 (0，1) , …, D100 (0，99) , wherein D is the unit number, (a, b) is the coordinate position, D1 (0，0) unit and D100 (0，99) unit are vertically arranged with a total length of 8 mm, and the 100 laser emission and receiving units are uniformly distributed on the dot laser emission and receiving system.

[0062] In this embodiment, by uniformly distributing 100 laser emission and reception units on the dot matrix laser emission and reception system, the uniformity of data collection is ensured, each area can be fully covered, avoiding the situation of insufficient local data collection, improving the comprehensiveness and accuracy of analysis. Since the total length of the vertical distance of the 100 units is set to 8mm and uniformly distributed on the system, higher spatial resolution can be achieved. This means that the system can more accurately capture the microstructure and details of the impact fracture of the welded joint, providing more detailed and accurate analysis results. The marking method of numbering and coordinate position makes the system have strong scalability. If it is necessary to further improve the resolution or cover a larger area, the laser emission and reception units can be simply increased or rearranged without redesigning the entire system.

[0063] By uniformly distributing the laser emission and reception units and setting the appropriate total length of the vertical distance, the purpose of this way is to improve the accuracy and efficiency of data collection. In this way, the data of the impact fracture of the welded joint can be more comprehensively and accurately obtained, so as to better analyze and evaluate. By setting 100 uniformly distributed laser units and controlling their vertical distance, finer spatial resolution is achieved. In this way, smaller scale features and changes can be captured, providing support for a deeper understanding of the performance of the welded joint.

[0064] Embodiment five, this embodiment is a further limitation of the welded joint impact fracture analysis system based on dot matrix laser scanning quantification of embodiment one, the method for controlling the time sequence of laser emission is:

[0065] Fast PIN photodiode is used to realize the emission of DG645 fast delay pulse emitter;

[0066] The rising edge response time of the PIN photodiode is in the order of nanoseconds, which is used to convert the optical signal into an electrical signal, and then the electrical delay of DG645 is set to control the synchronization of the photoelectric signal.

[0067] In this embodiment, fast PIN photodiode and DG645 fast delay pulse emitter are used, which can realize nanosecond level response time and precise time control. In this way, the time sequence of laser emission can be ensured to be accurate, so that data collection is more reliable and accurate. By setting the electrical delay of DG645 to control the synchronization of the photoelectric signal, the time synchronization between each laser emission unit can be ensured. In this way, the time deviation can be eliminated, the simultaneity of data collection is ensured, and the reliability and consistency of the analysis system are improved. Fast PIN photodiode has a faster rising edge response time, which is suitable for data collection in high-speed scanning process. This means that the system can complete the scanning and analysis of the impact fracture of the welded joint more quickly, improving the efficiency.

[0068] The purpose of using a fast PIN photodiode and a DG645 fast delay pulse emitter is to improve the control accuracy of the laser emission time sequence. This can ensure that the emission time of each laser unit is accurate during the scanning process of the impact fracture of the welded joint, so as to obtain accurate data. The synchronization of the optical signal is controlled by the electrical delay of the DG645, which aims to ensure that the data acquisition of each laser unit has high synchronization. This can avoid time misalignment during data acquisition and ensure the consistency and reliability of the data.

[0069] The fast PIN photodiode is responsible for converting optical signals into electrical signals. When laser irradiation reaches the photodiode, the rising edge response time is extremely short, and the optical signal can be quickly converted into an electrical signal. The DG645 fast delay pulse emitter is used to control the delay of the optical signal. By adjusting the electrical delay parameters of the DG645, the synchronization and delay of the optical signal can be accurately controlled, ensuring that the time sequence of data acquisition of each laser unit is correct. By reasonably setting and adjusting the parameters of the DG645, the optical signals of each laser unit can be kept in synchronization in time. This can ensure that the data of each data acquisition point has a consistent time marker during laser scanning, thereby ensuring the synchronization and accuracy of data acquisition.

[0070] Embodiment six, a welded joint impact fracture analysis method based on dot matrix laser scanning quantization, the method comprises:

[0071] Set the pulse frequency of the laser emission unit and the motion speed of the platform, start the dot matrix laser emission and receiving system (3) and the motion platform 5;

[0072] D1 (0，0) After the unit first emits laser and receives the reflected laser signal, the laser irradiation reflects back to the ranging receiving sensor of the unit, after receiving the reflected laser signal, D2 (0，1) The unit will continue to emit pulsed laser, and so on until D100 (0，99) After receiving the reflected laser signal at the corresponding position coordinate point, all data acquisition is completed;

[0073] With the horizontal movement of the motion platform 5, when the motion platform reaches the next preset position, D1 (1，0) Only then will the coordinate position fracture distance data be recorded, and the process will be repeated until D100 (99，99) Data acquisition is completed;

[0074] The collected data is processed by using the control and data processing system to obtain a plane fitting plane;

[0075] According to the fitting plane, the relative convex-concave value of the impact fracture is calculated;

[0076] The impact toughness of the welded joint is evaluated according to the relative convex-concave value of the impact fracture.

[0077] In this embodiment, through dot matrix laser scanning, each laser emitting unit emits laser only after receiving the reflection signal of the previous unit, ensuring that the fracture distance data at each coordinate position of the impact fracture of the welded joint can be accurately recorded, and high-precision data acquisition is realized. By using the dot matrix method, the entire welded joint area can be covered by continuously moving the motion platform, ensuring that the impact fracture data of all key areas are collected, improving the comprehensiveness and representativeness. The collected data are processed by using the control and data processing system, plane fitting analysis is performed, and the overall fitting plane is obtained. This helps to eliminate noise and extract main features, providing a reliable basis for subsequent relative convex-concave value calculation. By calculating the impact fracture relative convex-concave value of each coordinate point on the fitting plane, the unevenness of the joint can be quantitatively characterized. This analysis can provide more detailed information to help understand the specific morphology of the welded joint, rather than just the average information. The final analysis purpose is to evaluate the toughness of the welded joint through the relative convex-concave value of the impact fracture. This provides an evaluation method based on actual data, making the evaluation of joint quality and performance more accurate and reliable.

[0078] Specifically, through dot matrix laser scanning and data acquisition, the purpose is to accurately obtain the data of each coordinate position of the impact fracture of the welded joint, providing detailed and comprehensive information for subsequent analysis and evaluation. Through the horizontal movement of the motion platform, it is ensured that the data of all key areas are collected, increasing the comprehensiveness of the data and avoiding omission of specific areas of the welded joint. By calculating the relative convex-concave value of the impact fracture, the purpose is to provide a quantifiable index for evaluating the toughness of the welded joint. This is very important for predicting the performance of the welded joint in actual application. By using the dot matrix method, each laser unit emits laser according to a predetermined order, ensuring that data can be collected at each coordinate position. The collected data are used for plane fitting to obtain the overall fitting plane, which is used to eliminate noise and extract main features. On the basis of the fitting plane, the impact fracture relative convex-concave value of each coordinate point is calculated, which can be represented by the height difference from the fitting plane. Through the calculation of the relative convex-concave value, the toughness analysis of the welded joint is performed, providing a quantitative evaluation of the joint performance.

[0079] Embodiment seven, this embodiment is a further limitation of the welded joint impact fracture analysis method based on dot matrix laser scanning quantification according to embodiment six, the pulse frequency of the single laser emitting unit is set to 1 Hz, and the platform motion speed is set to 1 mm / s.

[0080] The present embodiment adopts a dot laser scanning quantification method, which can provide high-resolution images, making the analysis of the impact fracture of the welded joint more accurate. The pulse frequency of the single laser emitting unit is set to 1 Hz and the platform motion speed is set to 1 mm / s. This setting can ensure accurate data in the test, while making the experimental process easy to control. The fixed pulse frequency and motion speed help to improve the repeatability of the experiment, which is crucial for obtaining reliable experimental results. The defined parameter settings may be adapted to specific welded joint or impact fracture analysis requirements, making the method more practical.

[0081] Specifically, by fixing the pulse frequency of the laser emitting unit and the platform motion speed at specific values, the precise measurement and analysis of the impact fracture of the welded joint are achieved. By setting specific parameters, the experimental conditions are optimized to better meet the actual situation of the impact fracture analysis of the welded joint. The dot laser scanning method is used to irradiate the laser in dot form on the impact fracture of the welded joint, and the dot information is obtained by scanning to form a high-resolution image of the fracture surface. In practical applications, the setting of the pulse frequency of the single laser emitting unit and the platform motion speed will affect the density and speed of data acquisition, which is crucial for obtaining detailed and efficient impact fracture analysis data. The present embodiment defines the parameters of the dot laser scanning quantification method to improve the accuracy and reliability of the impact fracture analysis of the welded joint, and to adapt to specific practical application scenarios.

[0082] Embodiment eight, the present embodiment is a further limitation of the welded joint impact fracture analysis method based on dot laser scanning quantification according to embodiment six, wherein the relative convex-concave value of the impact fracture is calculated according to the fitting plane, comprising:

[0083]

[0084] wherein H is the relative convex-concave value of the impact fracture; S1 to S i is distance information; is a fitting plane.

[0085] The calculation of the relative convex-concave value in this embodiment can more comprehensively evaluate the morphology of the impact fracture of the welded joint and provide more quantitative analysis data. The relative convex-concave value can more finely characterize the surface geometric features of the impact fracture, including flatness, roughness, etc., and help to more deeply understand the performance of the welded joint. By fitting a plane to calculate the relative convex-concave value, a quantitative result can be obtained, making the analysis more comparable and repeatable. The calculation of the relative convex-concave value is introduced to improve the accuracy of impact fracture analysis and more accurately characterize the features of the impact fracture, providing a more reliable basis for subsequent engineering evaluation and improvement. The introduction of the relative convex-concave value makes the analysis not only limited to the description of the surface morphology, but also includes the geometric features of the surface, thereby expanding the dimension of the analysis and improving the comprehensiveness of the analysis.

[0086] For the point cloud data of the impact fracture, a plane model can be fitted using mathematical methods, which can fit the overall shape of the impact fracture surface. Based on the fitted plane, the distance of each sampling point to the fitted plane can be calculated, and then the relative convex-concave value is obtained. This value can represent the degree of convexity and concavity of the impact fracture surface, thereby reflecting the degree of unevenness of the surface. In the point cloud data obtained by point array laser scanning, the position information of each point can be used to calculate the distance to the fitted plane, thereby obtaining the relative convex-concave value.

[0087] Embodiment nine, this embodiment is a further limitation of the welded joint impact fracture analysis method based on point array laser scanning quantification of embodiment six, the relative convex-concave value of the impact fracture is analyzed to analyze the toughness of the welded joint, including:

[0088] The greater the relative convex-concave value of the impact fracture, the more the fracture form of the welded joint tends to be ductile fracture, that is, the better the toughness of the welded joint;

[0089] The smaller the relative convex-concave value of the impact fracture, the more the fracture form of the welded joint tends to be brittle fracture, that is, the worse the toughness of the welded joint.

[0090] In this embodiment, the toughness of the fracture form of the welded joint is judged by the size of the relative convex-concave value of the impact fracture, making the evaluation of toughness more intuitive and not requiring complex theoretical analysis, which is suitable for engineering practice. By using the relative convex-concave value, the toughness can be divided into different grades, thereby providing more specific and quantitative guidance for engineering design and material selection. This analysis method based on the relative convex-concave value is simple and easy to implement, suitable for actual production and laboratory testing, and improves the practicality of the analysis.

[0091] By analyzing the relative convex-concave value, the toughness of the welded joint can be predicted in advance, which helps to choose more suitable materials and processes in engineering design and manufacturing to meet specific use requirements. Through this method, the toughness condition of the welded joint can be monitored in real time during production, which helps to adjust the process parameters in time to ensure product quality. Through experiments and data analysis, the relationship between the relative convex-concave value of the impact fracture and the toughness of the welded joint is established. Generally, the larger the relative convex-concave value, the more uneven the fracture surface, which is related to ductile fracture. Through a large number of actual impact tests of welded joints, the data of fracture morphology and toughness performance under different relative convex-concave values are obtained. These data are used to verify and establish the correlation between the relative convex-concave value and the toughness. Through statistical and standardized processing of experimental data, the threshold value of the relative convex-concave value is determined, which is divided into two regions of ductile fracture and brittle fracture, providing an operable guide for engineering practice. Through the above principles, based on dot matrix laser scanning, the relative convex-concave value analysis can realize the rapid evaluation of the toughness of the welded joint, and provide a scientific basis for engineering decision-making. The smaller the relative convex-concave value, the more the fracture form of the welded joint tends to be brittle fracture, that is, the worse the toughness of the welded joint.

[0092] Embodiment ten, a welded joint impact fracture analysis device based on dot matrix laser scanning quantization according to the embodiment, the device comprises:

[0093] A frequency and speed setting unit is used to set the pulse frequency of the single laser emitting unit and the platform motion speed, and start the dot matrix laser emitting and receiving system and the motion platform.

[0094] A data acquisition unit is used to D1 (0，0) After the unit first emits laser and receives the reflected laser signal, the laser irradiated to the impact fracture is reflected back to the ranging receiving sensor of the unit, and after receiving the reflected laser signal, D2 (0，1) The unit will continue to emit pulsed laser, and so on until D100 (0，99) After receiving the reflected laser signal corresponding to the position coordinate point, all data acquisition is completed.

[0095] A horizontal moving unit is used for horizontal movement of the motion platform, and when the motion platform reaches the next preset position, D1 (1，0) The coordinate position fracture distance data is recorded, and the process is completed in sequence until D100 (99，99) Data acquisition is completed.

[0096] Embodiment eleven, see Figure 1 and Figure 2The embodiment is described. The embodiment is a specific embodiment of the welding joint impact fracture analysis system based on dot matrix laser scanning quantization described in embodiment one, and is also used for explaining embodiments two to five.

[0097] The V-shaped notch impact specimen of the TC4 titanium alloy welded joint with a size specification of 55 mm x 10 mm x 10 mm is obtained by using the laser-arc hybrid welding technology, and the size specification is as shown in the figure. Figure 2 The room temperature impact test is performed according to GB / T 2650-2008. During the test, the impact hammer is hammered at the back of the V-shaped notch to ensure that the impact specimen is fractured from the V-shaped notch, and the half of the fractured impact specimen is randomly selected and placed at the fixed fracture specimen clamping end for laser scanning ranging, and the opening side is placed at the upper position.

[0098] The dot matrix laser emission and receiving system and the impact fracture specimen end edge are made to be in the same plane by the motion platform, the platform motion speed is set to 1 mm / s, the single laser emitter pulse frequency is set to 1 Hz, and the dot matrix laser emission and receiving system and the motion platform are started. (0，0) The unit first emits pulsed laser, the position information is recorded as (0, 0), the laser is reflected to the ranging receiving sensor of the unit after irradiating the impact fracture, and the unit will continue to emit pulsed laser after receiving the reflected laser signal. (0，1) The position information is recorded as (0, 1), and so on until D100 (0，99) The position coordinate points (0, 0~99) are collected after the unit receives the reflected laser signal, and the collection of all data of the position coordinate points will be completed in microseconds. The method of the timing controller 6 for controlling the laser emission time sequence is to use the fast PIN photodiode to realize the DG645 fast delay pulse emitter, the PIN photodiode has a response time of nanoseconds to convert the optical signal into an electrical signal, and the synchronization of the photoelectric signal can be accurately controlled by setting the electrical delay of the DG645. The purpose of using this method is to avoid the reflected laser of each unit being received by the ranging receiving sensor of other units and causing data errors. The distance data of 10,000 position coordinate points obtained by the upper computer 7 are used for calculation.

[0099] With the movement of the platform, when the laser emitter reaches the preset pulse frequency, the unit continues to first emit pulsed laser, the position information is recorded as (1, 0), the laser is reflected to the ranging receiving sensor of the unit after irradiating the impact fracture, and the unit will continue to emit pulsed laser after receiving the reflected laser signal. (1，0) The position information is recorded as (1, 1), and so on until D100 (1，1) The position information is recorded as (1, 1), and so on until D100 (1，99)The position coordinate point (1, 0~99) is considered to be collected only after the unit receives the reflected laser signal.

[0100] Similarly, as the platform continues to move in the horizontal direction, (2, 0~99), (3, 0~99) … (99, 0~99) can be obtained, and finally each vertically distributed laser emitting and receiving unit can collect 100 position data of the fracture surface in the horizontal direction. The data set can be recorded as {D1[(0, 0), (1, 0), (2, 0), …, (99, 0)], D2[(0, 1), (1, 1), (2, 1) … (99, 1)], … D100[(0, 99), (1, 99), (2, 99) … (99, 99)]}, a total of 10000 distance information S 1～10000 .

[0101] 10000 distance information S 1～10000 After being transmitted to the computer and calculated by the software, the fitting plane can be obtained This plane is the mean plane of each data point. It can be calculated by formula 1 that the relative convex-concave value of the impact fracture is H:

[0102]

[0103] Finally, H = 0.375 after calculation. The H value can reflect the fracture property of the welded joint impact fracture. The larger the H value, the more the welded joint fracture tends to be ductile fracture, that is, the better the weld joint toughness. The smaller the H value, the more the welded joint fracture tends to be brittle fracture, that is, the worse the weld joint toughness. The reference threshold value of H provided by the embodiment is 0.35. When the H value exceeds the threshold value, it indicates that the weld joint toughness is good, and when the H value is less than the threshold value, it indicates that the weld joint toughness is poor. Of course, the threshold value of the welded joint of different materials and different processes will change to some extent, and should be analyzed according to the specific problem.

[0104] The welded joint impact fracture analysis system and method based on dot matrix laser scanning quantization provided by the embodiment is based on the Charpy V-notch impact test, and a dot matrix laser scanning device is used to collect data of the uneven cross section of the welded joint impact fracture. The time information of the return path of each scanning position is processed by mean value, and finally the convex-concave degree of the fracture cross section area is calculated by a calculation formula, so as to provide a quantitative, scientific and accurate test method for evaluating the toughness of the welded joint.

[0105] The above description of the technical solutions provided by the present application in combination with the drawings is further described in detail in order to highlight the advantages and benefits, and is not used as a limitation on the present application. Any modification, combination, improvement and equivalent replacement of the present application based on the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method for analyzing the impact fracture surface of welded joints based on fractional laser scanning quantization, characterized in that, The method is based on a fractional laser scanning quantization system for analyzing the impact fracture surface of welded joints. The analysis system includes: Fracture specimen clamping end (1), dot matrix laser emitting and receiving system (3), motion platform (5), control and data processing system; The dot matrix laser transmitting and receiving system (3) consists of n vertically distributed dot matrix laser transmitters and corresponding ranging and receiving sensor units. One dot matrix laser transmitter and one corresponding ranging and receiving sensor constitute one laser transmitting and receiving unit. The dot matrix laser transmitting and receiving system is divided into units, each of which is used to individually emit a pulsed laser with a preset frequency. The pulsed laser horizontally illuminates the impact fracture in front and then reflects back to the ranging and receiving sensor of the corresponding unit. The motion platform (5) is connected to the dot matrix laser transmitting and receiving system (3) to realize the one-dimensional horizontal motion of the dot matrix laser transmitting and receiving system; The fracture specimen clamping end (1) is used to fix the impact fracture specimen of the welded joint, with one side of the fracture facing the dot matrix laser emitter. The control and data processing system is used to control the timing sequence of the dot matrix laser emission of n units and to calculate the distance data of the coordinates of n positions. The value of n is 100; The 100 laser emitting and receiving units are numbered D1 from bottom to top. （0，0） D2 （0，1） ... D100 （0，99） Where D is the unit number, (a, b) is the coordinate position, and D1 （0，0） Unit and D100 （0，99） The total vertical distance between units is set to 8mm, and 100 laser emitting and receiving units are evenly distributed on the dot matrix laser emitting and receiving system; The method includes: Set the pulse frequency of the laser emitting unit and the platform movement speed, and start the dot matrix laser emitting and receiving system (3) and the motion platform (5). D1 （0，0） The unit first emits a laser and receives the reflected laser signal. The laser then illuminates the impact fracture and reflects back to the unit's ranging sensor. After receiving the reflected laser signal, D2... （0，1） The unit will then continue to emit pulsed lasers, and so on until D100. （0，99） All data acquisition is completed when the corresponding coordinate point is reached after the reflected laser signal is received. As the motion platform (5) moves horizontally, D1 will reach the next preset position. （1，0） Only then will the distance data of the break at that coordinate position continue to be recorded, and so on, until the 100th break point. （99，99） Data collection complete; The collected data is processed using a control and data processing system to obtain the plane fitting plane; The relative convexity / concavity values ​​of the impact fracture surface are calculated based on the fitted plane. The toughness of the welded joint is analyzed based on the relative convexity and concavity values ​​of the impact fracture surface. The dot matrix laser emitter has a core diameter of 0.05 mm and a ranging receiver sensor accuracy of 0.005 mm. The method for controlling the laser emission timing sequence is as follows: This is achieved using a fast PIN photodiode in conjunction with a DG645 fast delayed pulse transmitter. The rising edge response time of the PIN photodiode is on the order of nanoseconds. It is used to convert optical signals into electrical signals, and then the synchronization of the photoelectric signals is controlled by setting the electrical delay of the DG645.

2. The method for analyzing the impact fracture surface of welded joints based on fractional laser scanning quantization according to claim 1, characterized in that, The pulse frequency of a single laser emitting unit is set to 1 Hz, and the platform movement speed is set to 1 mm / s.

3. The method for analyzing the impact fracture surface of welded joints based on dot matrix laser scanning quantization according to claim 1, characterized in that, The calculation of the relative convexity / concavity value of the impact fracture surface based on the fitted plane includes: ， in, The relative convexity / concaveness of the impact fracture surface; S1 to S i This is distance information; This is the fitted plane.

4. The method for analyzing the impact fracture surface of welded joints based on fractional laser scanning quantization according to claim 1, characterized in that, The analysis of weld joint toughness based on the relative convexity / concaveness of the impact fracture surface includes: The larger the relative bump-to-dip value of the impact fracture surface, the more the material tends to fracture ductilely, and the better its toughness. The smaller the relative bump-to-dip value of the impact fracture surface, the more the material tends to fracture brittlely and the worse its toughness.

5. A device for analyzing the impact fracture surface of welded joints based on fractional laser scanning quantization, characterized in that, The device is implemented based on the method of claim 1, and the device comprises: The frequency and speed setting unit is used to set the pulse frequency of a single laser emitting unit and the platform movement speed, and to start the dot matrix laser emitting and receiving system and the motion platform. Data acquisition unit, used for D1 （0，0） The unit first emits a laser and receives the reflected laser signal. The laser then illuminates the impact fracture and reflects back to the unit's ranging sensor. After receiving the reflected laser signal, D2... （0，1） The unit will then continue to emit pulsed lasers, and so on until D100. （0，99） All data acquisition is completed when the corresponding coordinate point is reached after the reflected laser signal is received. The horizontal movement unit is used for the horizontal movement of the motion platform. After the motion platform reaches the next preset position, D1... （1，0） Only then will the distance data of the break at that coordinate position continue to be recorded, and so on, until the 100th break point. （99，99） Data collection is complete.

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