Design method, system and electronic equipment for marine diesel engine shafting

Abstract

The application discloses a design method, system and electronic equipment of a marine diesel engine shaft system, and belongs to the technical field of marine diesel engine design. The method comprises the following steps: constructing a torsional vibration coupling model according to the structure parameters of the crankshaft system, camshaft system and key accessory branch shaft system of the marine diesel engine shaft system; inputting an engine excitation load spectrum to the torsional vibration coupling model, and calculating the torsional vibration response parameters of each shaft system; identifying the vibration risk of each shaft system according to the torsional vibration response parameters, updating the torsional vibration coupling model according to the vibration risk of each shaft system, and obtaining a target torsional vibration coupling model, so as to design the marine diesel engine shaft system based on the target torsional vibration coupling model. The application can simultaneously consider the coupling relationship among the crankshaft system, camshaft system and key accessory branch shaft system in the model construction stage, and update the model through vibration risk feedback, so that the target model can accurately reflect the torsional vibration characteristics of each shaft system under complex working conditions.

Description

Technical Field

[0001] This application relates to the field of marine diesel engine design technology, specifically to a design method, system, and electronic equipment for a marine diesel engine shaft system. Background Technology

[0002] Marine diesel engine shafting is subjected to multiple excitations during operation, including cylinder combustion, inertial forces, transmission mechanisms, and fluctuations in operating conditions, which can easily lead to torsional vibration. For high-power, high-speed marine diesel engines, the shafting power density is high, and there are complex dynamic relationships between the crankshaft system, camshaft system, and various accessory branch shafts. Torsional vibration can affect the fatigue life of shafting components, transmission reliability, and overall engine operating safety.

[0003] In related technologies, during the design of marine diesel engine shafting systems, shafting torsional vibration models typically focus more on the vibration analysis of the main drive shafting. Furthermore, the model's ability to adapt and update to different shafting vibration risk states is limited, making it difficult for the model to accurately reflect the torsional vibration characteristics of each shafting system under complex operating conditions. Summary of the Invention

[0004] This invention provides a design method, system, and electronic equipment for marine diesel engine shafting, aiming to solve the problem in the related technology that it is difficult to accurately reflect the torsional vibration characteristics of each shaft under complex working conditions during the design process of marine diesel engine shafting.

[0005] In a first aspect, this application provides a design method for a marine diesel engine shafting system, comprising the following steps: Obtain the structural parameters of the marine diesel engine shafting system, which includes the crankshaft system, camshaft system, and key accessory branch shafting system; Based on the structural parameters, a torsional vibration coupling model is constructed; Input the engine excitation load spectrum into the torsional vibration coupling model and calculate the torsional vibration response parameters of each shaft system; The vibration risk of each shaft system is identified based on the torsional vibration response parameters, and the torsional vibration coupling model is updated based on the vibration risk of each shaft system to obtain the target torsional vibration coupling model, so as to design the marine diesel engine shaft system based on the target torsional vibration coupling model.

[0006] In some embodiments, a torsional vibration coupling model is constructed based on the structural parameters, including: The structural parameters are transformed to obtain shaft system modeling data that characterizes the shaft system connection relationship, rotational inertia distribution, torsional stiffness distribution and damping distribution; Based on the shaft system modeling data, determine the shaft system topology; Based on the aforementioned shaft system topology, determine the power transmission path between each shaft system; Establish a main shaft system model and a branch shaft system model along the power transmission path; Based on the transmission constraint relationship between the main shaft system model and the branch shaft system model, the torsional vibration coupling model is constructed.

[0007] In some embodiments, determining the shaft system topology based on the shaft system modeling data includes: Using the torque-transmitting connection relationship as the boundary, the crankshaft system, the camshaft system, and the key accessory branch shaft system are mapped into a shaft system topology with connection nodes and transmission edges; The connecting node represents the rotational degree of freedom in the shaft system, and the transmission edge represents the torque transmission relationship between adjacent rotational degrees of freedom.

[0008] In some embodiments, establishing a main shaft system model and a branch shaft system model along the power transmission path includes: Based on the shaft system modeling data, determine the rotational inertia distribution, torsional stiffness distribution, and damping distribution in the crankshaft system and the camshaft system; The structure whose contribution is mainly due to rotational inertia is equivalent to rotational degrees of freedom, and the structure whose contribution is mainly due to torsional deformation is equivalent to the elastic transfer relationship connecting adjacent rotational degrees of freedom. Based on the rotational degrees of freedom, the elastic transmission relationship, and the damping distribution, the principal shaft system model is established.

[0009] In some embodiments, establishing a main shaft system model and a branch shaft system model along the power transmission path includes: Based on the shaft system modeling data, determine the equivalent inertia, equivalent torsional stiffness, and equivalent damping of the key accessory branch shaft system; The key accessory branch shaft system is considered as a flexible subsystem with independent rotational degrees of freedom; The branch shaft system model is established based on the equivalent inertia, equivalent torsional stiffness, equivalent damping, and independent rotational degrees of freedom.

[0010] In some embodiments, the torsional vibration coupling model is constructed based on the transmission constraint relationship between the main shaft system model and the branch shaft system model, including: Determine the connection position between the key accessory branch shaft system and at least one of the crankshaft system and the camshaft system; Based on the connection position, transmission ratio, and transmission direction, determine the angular displacement constraint relationship and torque transmission relationship between the main shaft system model and the branch shaft system model; The angular displacement constraint relationship and the torque transmission relationship are introduced between the main shaft system model and the branch shaft system model to form the torsional vibration coupling model.

[0011] In some embodiments, the angular displacement constraint relationship and the torque transmission relationship are introduced between the main shaft system model and the branch shaft system model to form the torsional vibration coupling model, including: Based on the angular displacement constraint relationship, the rotational degrees of freedom in the branch shaft system model are mapped to the corresponding rotational degrees of freedom in the main shaft system model; Based on the torque transmission relationship, the equivalent inertial torque and / or equivalent elastic torque generated by the branch shaft system model are fed back to the main shaft system model; Based on the mapped rotational degrees of freedom and the feedback torque transmission relationship, the torsional vibration coupling model is formed.

[0012] In some embodiments, the method further includes: For shaft components with non-uniform cross sections or transitional connection structures, local stiffness correction is performed to obtain the corrected stiffness; Based on the corrected stiffness, the torsional vibration coupling model is constructed.

[0013] In some embodiments, the step of performing local stiffness correction on shaft system portions with non-uniform cross sections or transition connection structures to obtain corrected stiffness includes: A local finite element model is established based on the actual geometric structure of the shaft system to be corrected. Based on the local finite element model, the equivalent torsional stiffness of the shaft system to be corrected is calculated. The equivalent torsional stiffness is used to replace or modify the corresponding stiffness in the torsional vibration coupling model to obtain the modified stiffness.

[0014] In some embodiments, the engine excitation load spectrum is input into the torsional vibration coupling model to calculate the torsional vibration response parameters of each shaft system, including: The engine excitation load spectrum is converted into external excitation torques acting on the corresponding rotational degrees of freedom in the torsional vibration coupling model; Based on the external excitation torque driving the torsional vibration coupling model, the torsional vibration response is determined; Based on the torsional vibration response, the torsional vibration response parameters of each shaft system are calculated; The torsional vibration response parameters include one or more of the following: torsional angular displacement, torsional velocity, torsional torque, and torsional stress of the crankshaft system, the camshaft system, and the key accessory branch shaft system.

[0015] In some embodiments, identifying the vibration risk of each shaft system based on the torsional vibration response parameters includes: The torsional vibration response parameters of the crankshaft system, the camshaft system, and the key accessory branch shaft system are compared with their respective safety criteria. If the torsional vibration response parameters of any shaft system do not meet the corresponding safety criteria, the shaft system with vibration risk is identified.

[0016] In some embodiments, the torsional vibration coupling model is updated according to the vibration risk of each shaft system to obtain a target torsional vibration coupling model, including: Adjust the model parameters corresponding to the shaft system with vibration risk to obtain the adjusted model parameters; The torsional vibration coupling model is updated using the adjusted model parameters. The engine excitation load spectrum was re-input into the updated torsional vibration coupling model, and the torsional vibration response parameters were recalculated. If the torsional vibration response parameters of each shaft system meet the corresponding safety criteria, the updated torsional vibration coupling model is determined as the target torsional vibration coupling model.

[0017] Secondly, a design system for a marine diesel engine shafting system includes: The parameter acquisition module is used to acquire the structural parameters of the marine diesel engine shafting system, which includes the crankshaft system, camshaft system, and key accessory branch shafting system. The model building module is used to build a torsional vibration coupling model based on the structural parameters, wherein the key accessory branch shaft system is coupled to at least one of the crankshaft system and the camshaft system; The vibration response calculation module is used to input the engine excitation load spectrum into the torsional vibration coupling model and calculate the torsional vibration response parameters of each shaft system. An optimization module is used to identify the vibration risk of each shaft system based on the torsional vibration response parameters, and update the torsional vibration coupling model based on the vibration risk of each shaft system to obtain a target torsional vibration coupling model, so as to design the marine diesel engine shaft system based on the target torsional vibration coupling model.

[0018] Secondly, a design system for a marine diesel engine shafting system is also provided, including: The parameter acquisition module is used to acquire the structural parameters of the marine diesel engine shafting system, which includes the crankshaft system, camshaft system, and key accessory branch shafting system. The model building module is used to construct a torsional vibration coupling model based on structural parameters, wherein the key accessory branch shaft system is coupled to at least one of the crankshaft system and the camshaft system. The vibration response calculation module is used to input the engine excitation load spectrum into the torsional vibration coupling model and calculate the torsional vibration response parameters of each shaft system. The optimization module is used to identify the vibration risk of each shaft system based on the torsional vibration response parameters, and update the torsional vibration coupling model according to the vibration risk of each shaft system to obtain the target torsional vibration coupling model, so as to design the marine diesel engine shaft system based on the target torsional vibration coupling model.

[0019] Thirdly, embodiments of this application provide an electronic device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the method described in any of the above-mentioned embodiments.

[0020] Fourthly, embodiments of this application provide a computer-readable storage medium having a computer program stored thereon, the computer program being loaded by a processor to perform the steps in any of the methods described above.

[0021] Beneficial effects: This application obtains the structural parameters of the marine diesel engine shafting system, including the crankshaft system, camshaft system, and key accessory branch shafting, and constructs a torsional vibration coupling model based on these parameters. This model can simultaneously characterize the dynamic relationship between the main shafting system and the key accessory branch shafting at the model level, avoiding insufficient characterization of coupled vibration characteristics caused by modeling only a single shafting system or a local shafting system. By inputting the engine excitation load spectrum into the torsional vibration coupling model and calculating the torsional vibration response parameters of each shafting system, the torsional vibration response of the crankshaft system, camshaft system, and key accessory branch shafting under the actual excitation of the engine can be obtained. Based on the torsional vibration response parameters, the vibration risk of each shafting system is identified, and the torsional vibration coupling model is updated based on the vibration risk. This allows the model to be iteratively corrected according to the risk status of different shafting systems, thereby obtaining a target model that better reflects the true torsional vibration characteristics and improving the accuracy of the torsional vibration response of each shafting system in the marine diesel engine. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic flowchart illustrating a design method for a marine diesel engine shafting system provided in an exemplary embodiment of this application; Figure 2 This is a schematic diagram of a torsional vibration coupling model construction process provided by an exemplary embodiment of this application; Figure 3 This is a schematic flowchart of another marine diesel engine shaft system design method provided by an exemplary embodiment of this application; Figure 4 This is a schematic diagram of the functional modules of a marine diesel engine shafting design system provided in an exemplary embodiment of this application; Figure 5 This is a schematic diagram of the electronic device structure provided by an exemplary embodiment of this application. Detailed Implementation

[0024] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0025] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0026] "A and / or B" includes the following three combinations: A only, B only, and a combination of A and B.

[0027] The use of "applies to" or "configured to" in this application implies open and inclusive language, which does not exclude the applicability to or configuration to devices performing additional tasks or steps. Additionally, the use of "based on" implies openness and inclusivity, because processes, steps, calculations, or other actions "based on" one or more of the stated conditions or values ​​may in practice be based on additional conditions or values ​​beyond those stated.

[0028] In this application, the term "exemplary" is used to mean "used as an example, illustration, or description." Any embodiment described as "exemplary" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use this application. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that this application can be made without using these specific details. In other instances, well-known structures and processes are not described in detail to avoid obscuring the description of this application with unnecessary detail. Therefore, this application is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0029] Firstly, this embodiment provides a design method for a marine diesel engine shafting system. Please refer to [link to relevant documentation]. Figure 1 This includes steps S100 to S400.

[0030] Step S100: Obtain the structural parameters of the marine diesel engine shaft system, which includes the crankshaft system, camshaft system, and key accessory branch shaft system.

[0031] Specifically, the structural parameters of the marine diesel engine shafting system are obtained. The marine diesel engine shafting system includes the crankshaft system, camshaft system, and key accessory branch shafting systems. For example, the key accessory branch shafting system can be a freshwater pump shafting system, a seawater pump shafting system, a lubricating oil pump shafting system, or a fuel pump shafting system. The structural parameters can be derived from diesel engine design drawings, shafting layout diagrams, 3D models, component quality attribute files, or test calibration data.

[0032] Step S200: Construct a torsional vibration coupling model based on the structural parameters.

[0033] Specifically, after obtaining the structural parameters, a torsional vibration coupling model is constructed based on these parameters. In this model, the key accessory branch shaft system is not simply treated as an additional mass, but rather coupled to at least one of the crankshaft system and camshaft system, enabling the model to characterize the power transmission relationship between the main shaft system and the accessory branch shaft system.

[0034] Step S300: Input the engine excitation load spectrum into the torsional vibration coupling model and calculate the torsional vibration response parameters of each shaft system.

[0035] Specifically, the engine excitation load spectrum is input into the constructed torsional vibration coupling model to simulate the external excitation effect during actual diesel engine operation. Through calculation and analysis, the torsional vibration response parameters corresponding to the crankshaft system, camshaft system, and various key accessory branch shaft systems are obtained, fully reflecting the vibration state of each shaft system. The engine excitation load spectrum is used to recreate the actual stress state of the engine in the shaft system torsional vibration simulation, driving the model to calculate the torsional vibration response parameters of each shaft system. For example, it can include at least one of the following excitation data: cylinder combustion, reciprocating and rotational inertial forces, valve train operation, speed fluctuations, and operating conditions.

[0036] Step S400: Identify the vibration risk of each shaft system based on the torsional vibration response parameters, and update the torsional vibration coupling model based on the vibration risk of each shaft system to obtain the target torsional vibration coupling model, so as to design the marine diesel engine shaft system based on the target torsional vibration coupling model.

[0037] Specifically, based on the calculated torsional vibration response parameters, it is determined whether there is a vibration risk in each shaft system. For shaft systems with risks, the torsional vibration coupling model is adjusted and updated. The detection and correction work is repeated to obtain a target torsional vibration coupling model that meets the usage requirements.

[0038] This embodiment can simultaneously consider the coupling relationship between the crankshaft system, camshaft system and key accessory branch shaft system during the model construction stage, and update the model through vibration risk feedback, so that the target model can accurately reflect the torsional vibration characteristics under complex working conditions.

[0039] In some embodiments, the torsional vibration coupling model is constructed based on structural parameters in step S200. (See also...) Figure 2 This includes steps S210 to S250.

[0040] Step S210: Perform equivalent transformation on the structural parameters to obtain shaft system modeling data that characterizes the shaft system connection relationship, rotational inertia distribution, torsional stiffness distribution and damping distribution.

[0041] Specifically, the original structural parameters of the crankshaft system, camshaft system, and key accessory branch shaft systems obtained in the early stage were equivalently transformed. Combined with the actual requirements of torsional vibration modeling, the original information such as the physical structure, dimensions, and assembly methods of various components were standardized and transformed. During the transformation process, the assembly connection methods between each component were systematically reviewed, the rotational inertia distribution at different positions of the entire shaft system was statistically analyzed, and the torsional stiffness and damping characteristics of different shaft segments and connection structures were distinguished. A set of modeling data that can completely characterize the shaft system's connection relationships, rotational inertia distribution, torsional stiffness distribution, and damping distribution was compiled.

[0042] Step S220: Determine the topological relationship of the shaft system based on the shaft system modeling data.

[0043] Specifically, based on the equivalent-transformed shaft system modeling data, the overall architecture of the entire diesel engine shaft system is analyzed. The shaft system modeling data is used to characterize the shaft system connections, moment of inertia distribution, torsional stiffness distribution, and damping distribution. For example, based on the 3D models or design drawings of the parts, structures such as crankshafts, flywheels, gears, camshafts, and accessory pump shafts can be transformed into data formats suitable for dynamic modeling. According to the actual boundaries of torque transmission and component assembly, the crankshaft system, camshaft system, and various key accessory branch shaft systems are divided into constituent units. The connection logic, combination forms, and spatial layout between different units are clarified, and the position and relationship of each functional component in the overall shaft system are determined. Thus, a complete and clear shaft system topology is determined, intuitively presenting the overall architecture and interconnection rules of all components of the entire shaft system.

[0044] Step S230: Determine the power transmission path between each shaft system based on the shaft system topology.

[0045] Specifically, based on the established shaft system topology, following the actual flow of power transmission and combining the transmission structure and assembly sequence of each shaft system, the power transmission process between the crankshaft system and camshaft system is traced. At the same time, the direction and channel of power diversion from the main transmission structure to each key accessory branch shaft system are further determined, and the coherent power transmission path between all components and units within the entire shaft system is sorted out, thus defining a clear sequence and scope for building regional models.

[0046] Step S240: Construct the main shaft system model and the branch shaft system model along the power transmission path.

[0047] Specifically, models were built along the defined power transmission path. First, for the main shaft system composed of the crankshaft and camshaft systems, its structural features and dynamic properties were reconstructed based on the corresponding modeling data, completing the main shaft system model. Then, for the branch shaft systems composed of various key accessories such as freshwater pumps and seawater pumps, corresponding branch shaft system models were independently built based on relevant data such as the inertia, stiffness, and damping of the branch parts. Both models strictly followed the actual structure and power transmission sequence, respectively reproducing the operating characteristics of the main shaft system and the branch shaft systems.

[0048] Step S250: Construct a torsional vibration coupling model based on the transmission constraint relationship between the main shaft system model and the branch shaft system model.

[0049] Specifically, by combining the transmission coordination methods, positional constraints, and transmission matching rules of the main shaft system model and each branch shaft system model in actual equipment, the transmission constraint relationship between the two types of models is clarified. According to the actual transmission logic, the independent main shaft system model and branch shaft system model are docked and integrated to build a mutually matching transmission relationship, so that the dynamic and vibration states of each part of the model can be mutually transmitted and influenced. A complete torsional vibration coupling model is constructed using the dispersed main shaft system model and branch shaft system model.

[0050] This embodiment standardizes and equivalently transforms the original structural parameters of the shaft system, sorts out the shaft system topology and power transmission path based on the modeling data, and then builds the main shaft system and branch shaft system models in modules and completes the overall coupling by combining actual transmission constraints. It can transform the complex solid shaft system structure of the diesel engine into a logically clear dynamic model that fits the actual transmission law, and fully restores the connection relationship, power transmission and interaction characteristics of the main shaft system and the accessory branch shaft system, thereby effectively ensuring the authenticity and integrity of the torsional vibration coupling model.

[0051] In some embodiments, determining the shaft system topology based on the shaft system modeling data in step S220 includes: Using the torque-transmitting connection relationship as the boundary, the crankshaft system, camshaft system and key accessory branch shaft system are mapped into a shaft system topology with connection nodes and transmission edges; In this context, the connecting nodes represent the rotational degrees of freedom in the shaft system, and the transmission edges represent the torque transmission relationship between adjacent rotational degrees of freedom.

[0052] Specifically, based on the shaft system modeling data that has undergone equivalent transformation, the various connection structures that actually transmit torque in the entire shaft system are used as the dividing boundaries. The crankshaft system, camshaft system, and various key accessory branch shaft systems are abstractly mapped, transforming the real mechanical shaft system into a topological structure composed of connection nodes and transmission edges. During the mapping process, components and structures capable of independent rotational motion within the shaft system are designated as connection nodes, representing the rotational degrees of freedom of the shaft system. Shaft segments, gear meshing structures, and transmission connectors that transmit torque between adjacent nodes are designated as transmission edges. These transmission edges demonstrate the torque transmission logic between different rotating parts, clearly outlining the topological architecture of the entire shaft system and presenting the distribution, connection, and basic framework of power transmission for each shaft system unit.

[0053] For example, the crankshaft front end, flywheel end, camshaft gear end, and accessory pump input end can be abstracted as connection nodes; the crankshaft shaft segment, gear meshing relationship, camshaft shaft segment, and accessory pump drive shaft segment can be abstracted as transmission edges. Through this topology, it is possible to determine whether there is a direct or indirect torque transmission relationship between each node, and to determine the connection position of the key accessory branch shaft system relative to the main shaft system.

[0054] In some embodiments, the construction of the main shaft system model and the branch shaft system model along the power transmission path in step S240 includes steps S240 to S243.

[0055] Step S241: Based on the shaft system modeling data, determine the distribution of rotational inertia, torsional stiffness, and damping in the crankshaft system and camshaft system.

[0056] Specifically, for the main shaft system composed of the crankshaft system and the camshaft system, the shaft system modeling data is used to examine each component and shaft segment structure within the main shaft system one by one to determine the distribution of rotational inertia at different positions of the entire main shaft system. At the same time, the torsional stiffness differences of each shaft segment and connecting structure are distinguished, and the damping distribution state corresponding to various connecting parts is sorted out to obtain the overall distribution law of various dynamic properties of the main shaft system.

[0057] Step S242: The structure whose contribution is mainly due to rotational inertia is equivalent to rotational degrees of freedom, and the structure whose contribution is mainly due to torsional deformation is equivalent to the elastic transfer relationship connecting adjacent rotational degrees of freedom.

[0058] Specifically, the components of the main shaft system are simplified according to their structural functions. Structures such as flywheels, gears, and crankshaft counterweights, which mainly rely on their own mass to generate rotational inertia, are uniformly equivalent to independent rotational degrees of freedom. Furthermore, structures such as crankshaft segments and camshaft segments, which are prone to torsional deformation and mainly bear torque transmission, are equivalent to elastic transmission relationships connecting the various rotational degrees of freedom. In this way, the complex solid mechanical structure is transformed into a simplified form that adapts to dynamic modeling.

[0059] For example, structures such as crankshaft counterweights, flywheels, and gears, which are mainly contributed by rotational inertia, can be equivalent to rotational degrees of freedom; structures such as crankshaft main journals, crank pins, and camshaft segments, which are mainly contributed by torsional deformation, can be equivalent to the elastic transmission relationship connecting adjacent rotational degrees of freedom.

[0060] Step S243: Construct the principal axis model based on rotational degrees of freedom, elastic transmission relationship, and damping distribution.

[0061] Specifically, when constructing the main shaft system model, rotational degrees of freedom can be arranged sequentially along the power transmission path from the crankshaft system to the camshaft system, and adjacent rotational degrees of freedom can be connected through elastic transmission relationships. Simultaneously, damping distribution is set according to material damping, connection damping, or empirical damping parameters. Based on the rotational degrees of freedom, elastic transmission relationships, and damping distribution, all equivalent units are sequentially connected according to the actual assembly and transmission sequence, restoring the true structural characteristics and power transmission logic of the main shaft system, thus constructing a main shaft system model integrating the crankshaft system and the camshaft system.

[0062] This embodiment first clarifies the distribution characteristics of rotational inertia, torsional stiffness, and damping at various points in the main shaft system. Then, based on the structural function, it performs reasonable equivalent simplification, converting different components into rotational degrees of freedom and elastic transmission relationships. Finally, it builds a main shaft system model by combining various dynamic parameters and the actual transmission sequence. This not only reasonably simplifies the complex solid structure and reduces the difficulty of modeling and calculation, but also fully preserves the core dynamic characteristics and power transmission laws of the crankshaft system and camshaft system, making the built main shaft system model fit the actual operating state of the equipment.

[0063] In some embodiments, the construction of the main shaft system model and the branch shaft system model along the power transmission path in step S240 includes steps S244 to S246.

[0064] Step S244: Based on the shaft system modeling data, determine the equivalent inertia, equivalent torsional stiffness, and equivalent damping of the key accessory branch shaft system.

[0065] Specifically, based on the shaft system modeling data, parameter integration was carried out for various key accessory branch shaft systems such as freshwater pumps and seawater pumps. Combining the structural characteristics, assembly form, and motion state of each component within the branch shaft system, the equivalent inertia of the entire branch shaft system was comprehensively calculated. The overall equivalent torsional stiffness was determined by combining the structural characteristics of pump shafts, transmission connectors, etc. The equivalent damping of the entire branch shaft system was determined by combining the bearing, seal, transmission fit position, and load effects. All core dynamic parameters of the branch shaft system were comprehensively identified.

[0066] Taking the seawater pump shaft system as an example, the seawater pump gears, impellers and pump shaft rotor can form equivalent inertia, the pump shaft and its connecting sections can form equivalent torsional stiffness, and the bearings, seals and fluid load effects can form equivalent damping.

[0067] Step S245: Treat the key accessory branch shaft system as a flexible subsystem with independent rotational degrees of freedom.

[0068] Specifically, we abandon the simplistic approach of treating the accessory branch shaft system as a single point of added mass. Instead, we define it holistically from the perspective of dynamic characteristics, treating each set of key accessory branch shaft systems as a complete independent unit. We confirm its rotational motion form and rotational degrees of freedom, and identify it as a flexible subsystem with its own deformation capability and dynamic response characteristics, fully reflecting the structural attributes and motion characteristics of the branch shaft system itself.

[0069] Step S246: Construct a branch shaft system model based on equivalent inertia, equivalent torsional stiffness, equivalent damping, and independent rotational degrees of freedom.

[0070] Specifically, using the equivalent inertia, equivalent torsional stiffness, and equivalent damping obtained from the analysis as basic parameters, and combining them with the independent rotational degrees of freedom corresponding to the branch shaft system, strictly adhering to the predetermined power transmission path and the actual assembly structure of the branch shaft system, the various parameters and motion characteristics are combined and arranged in an orderly manner to fully reproduce the transmission characteristics, deformation characteristics, and motion laws of the accessory branch shaft system, thus constructing a branch shaft system model that conforms to the actual operating state. This branch shaft system model can independently reflect the torsional response of the accessory branch shaft system and can be coupled with the main shaft system model.

[0071] This embodiment first integrates and calculates the core dynamic parameters such as the equivalent inertia, equivalent torsional stiffness, and equivalent damping of various accessory branch shaft systems. Instead of simply treating the branch shaft system as an added mass, it defines it as a flexible subsystem with independent rotational degrees of freedom. Then, it combines various parameters and power transmission paths to build a branch shaft system model. This can fully preserve the structural deformation and dynamic response characteristics of the accessory branch shaft system itself, truly restore its torsional vibration performance, and also ensure that the model can be successfully coupled and connected with the main shaft system model, effectively avoiding calculation deviations caused by oversimplification.

[0072] In some embodiments, step S250, which involves constructing a torsional vibration coupling model based on the transmission constraint relationship between the main shaft system model and the branch shaft system model, includes steps S251 to S253.

[0073] Step S251: Determine the connection position between the critical accessory branch shaft system and at least one of the crankshaft system and camshaft system.

[0074] Specifically, based on the actual assembly structure and transmission layout of the diesel engine shaft system, the installation points of each key accessory branch shaft system are checked one by one. The corresponding positions where the branch shaft system connects to the crankshaft system or camshaft system via gears or other transmission structures are determined, and the connection points between the branch shaft system and the main shaft system are accurately located. For example, the freshwater pump shaft system can be connected to the camshaft system via a gear transmission mechanism, while the seawater pump shaft system can be connected to the crankshaft system or camshaft system via an intermediate gear.

[0075] Step S252: Determine the angular displacement constraint relationship and torque transmission relationship between the main shaft system model and the branch shaft system model based on the connection position, transmission ratio and transmission direction.

[0076] Specifically, based on the determined connection positions, combined with the actual transmission ratios and power transmission directions of each transmission structure, and according to the actual transmission ratios and steering requirements of transmission structures such as gears, the angular displacement constraint relationships that the rotation angles and rotation speeds of the two models, the main shaft system and the branch shaft system, satisfy are specified. At the same time, the transmission relationship between power and vibration torque in the two models is clarified, and the transmission operation rules between the two types of models are fully defined.

[0077] Step S253: Introduce the angular displacement constraint relationship and torque transmission relationship between the main shaft system model and the branch shaft system model to form a torsional vibration coupling model.

[0078] Specifically, the angular displacement constraint relationship and torque transmission relationship that have been sorted out are applied to the connection position of the main shaft system model and the branch shaft system model, so that the two originally independent models are linked according to the actual transmission logic, realizing synchronous matching of rotational state and bidirectional torque transmission, so that the various models form a whole that can influence each other and operate in coordination, and combine to construct a complete torsional vibration coupling model.

[0079] This embodiment first accurately determines the actual connection positions of each key accessory branch shaft system with the crankshaft system and camshaft system. Then, based on the connection position, transmission ratio, and transmission direction, it clarifies the angular displacement constraints and bidirectional torque transmission rules between the main shaft system model and the branch shaft system model. By introducing corresponding transmission constraint relationships between the two independent models, overall coupling is achieved. This can highly restore the real transmission linkage mechanism between the main shaft system and each accessory branch shaft system of the marine diesel engine. It can accurately simulate the mutual transmission and dynamic influence of vibration torque between the main and branch shaft systems, avoid simulation errors caused by ignoring the coupling effect between shaft systems, and effectively improve the authenticity and reliability of the simulation results of the torsional vibration of the whole machine shaft system.

[0080] In some embodiments, step S253, which introduces the angular displacement constraint relationship and torque transmission relationship between the main shaft system model and the branch shaft system model to form a torsional vibration coupling model, includes steps S2531 to S2533.

[0081] Step S2531: Based on the angular displacement constraint relationship, map the rotational degrees of freedom in the branch shaft system model to the corresponding rotational degrees of freedom in the main shaft system model.

[0082] Specifically, based on the angular displacement constraint relationship and combined with the transmission coordination rules between the main shaft system and the branch shaft system, the corresponding rotational degrees of freedom within the branch shaft system model are matched to the rotational degrees of freedom at the connection points of the main shaft system model. This ensures that the rotational units of the two models form a linked correspondence, guaranteeing that their rotational states remain synchronized according to the actual transmission law. For example, when the branch shaft system is connected to the main shaft system via gears, the angular displacement at the input end of the branch shaft system can be mapped to the angular displacement of the corresponding gear node in the main shaft system according to the gear transmission ratio.

[0083] Step S2532: Based on the torque transmission relationship, feed back the equivalent inertial torque and / or equivalent elastic torque generated by the branch shaft system model to the main shaft system model.

[0084] Specifically, based on the established torque transmission relationship, the mechanical effects under actual operating conditions are simulated. The equivalent inertial torque and equivalent elastic torque generated during the operation of the branch shaft system are transmitted in the reverse direction along the transmission structure and act on the main shaft system model. This fully recreates the mechanical feedback effect of the branch shaft system on the main shaft system, demonstrating the bidirectional torque interaction process between the two. For example, when the impeller of the accessory pump has a large equivalent inertia, the equivalent inertial torque generated near acceleration, deceleration, or resonance can be fed back to the main shaft system through gear transmission.

[0085] Step S2533: Based on the mapped rotational degrees of freedom and the feedback torque transmission relationship, a torsional vibration coupling model is formed.

[0086] Specifically, using the mapped rotational degrees of freedom as the basis for motion linkage, and combining the constructed torque transmission and feedback relationship, the main shaft system model and each branch shaft system model are integrated into a whole, so that each part can not only meet the rotational coordination requirements, but also realize the mutual transmission and influence of torque, thereby forming a torsional vibration coupling model that can truly reflect the linkage characteristics of the entire shaft system.

[0087] This embodiment first establishes the mapping relationship between the rotational degrees of freedom of the branch shaft system and the main shaft system based on the angular displacement constraint relationship, ensuring that the rotational operation law of the two types of models is consistent with the actual transmission conditions. Then, according to the torque transmission relationship, the equivalent inertial torque and equivalent elastic torque generated during the operation of the branch shaft system are fed back to the main shaft system model, fully reproducing the bidirectional mechanical interaction between the main and branch shaft systems. Based on the degree of freedom mapping relationship and torque feedback transmission relationship, the multi-model integration is achieved, which can effectively avoid the simulation distortion problem caused by ignoring transmission constraints and the bidirectional torque coupling effect, and accurately restore the vibration mutual excitation effect between various parts of the whole machine shaft system, thereby greatly improving the accuracy of the torsional vibration simulation calculation results.

[0088] In some embodiments, the above-described method for constructing a torsional vibration model of a marine diesel engine shaft system further includes steps S260-S270.

[0089] Step S260: Perform local stiffness correction on shaft parts with non-uniform cross sections or transition connection structures to obtain the corrected stiffness.

[0090] Specifically, considering the need to handle non-uniform cross-sections such as crankshaft transition fillets, stepped shaft sections, crank arm connection areas, and keyways within the shaft system, as well as various irregular transition connection structures, directly simplifying these complex structures as conventional shaft sections would lead to deviations in stiffness calculations. This embodiment analyzes the actual shape and structural characteristics of these special parts, recalculates their true torsional stiffness values, corrects the original simplified stiffness, and obtains local structural stiffness parameters that conform to actual working conditions.

[0091] For example, if the area connecting the crankshaft main journal and the crank arm is directly equivalent to a regular cylindrical shaft segment, it may lead to a deviation in torsional stiffness. In this case, a local stiffness correction can be made for this area, and the corrected stiffness can be used to construct a torsional vibration coupling model, so that the stiffness of the corresponding part in the model is closer to the actual structure.

[0092] Step S270: Based on the corrected stiffness, construct a torsional vibration coupling model.

[0093] Specifically, by using the corrected local stiffness parameters to replace the original stiffness data at the corresponding positions in the torsional vibration coupling model, and then combining the determined rotational degrees of freedom, elastic transmission relationships, torque constraints, and various dynamic parameters, the various model units are reassembled to obtain a torsional vibration coupling model with higher accuracy and better fit to the characteristics of the actual structure.

[0094] This embodiment addresses the local stiffness correction of non-uniform cross-sections and irregular transition connection structures such as crankshaft transition fillets, stepped shaft sections, and crank arm connection areas. This avoids the torsional stiffness calculation deviation caused by directly using the equivalent method of regular cylindrical shaft sections. By replacing the original simplified stiffness parameters in the model with the corrected stiffness that fits the actual structural characteristics, and then building the torsional vibration coupling model, the accuracy of the dynamic parameters at key structural positions can be effectively improved. This makes the constructed simulation model closer to the real mechanical deformation characteristics of the diesel engine shaft system and significantly reduces the simulation error caused by structural simplification.

[0095] In some embodiments, step S260 involves local stiffness correction of the shaft system portion with non-uniform cross-section or transition connection structure to obtain the corrected stiffness, including steps S261 to S263.

[0096] Step S261: Based on the actual geometric structure of the shaft system to be corrected, construct a local finite element model.

[0097] Specifically, for special structural regions in the shaft system with uneven cross-sections and transitional joints, a corresponding local finite element model is built according to the actual geometric shape, dimensional parameters, and assembly connection form of the part, to replicate the actual appearance and construction characteristics of the complex structure. For example, a local finite element model including realistic fillets, cross-sectional changes, and connection contours is constructed for the crankshaft transition connection region, and torsional load boundary conditions are applied to the local finite element model.

[0098] Step S262: Calculate the equivalent torsional stiffness of the shaft system to be corrected based on the local finite element model.

[0099] Specifically, on the established local finite element model, the actual working condition of the diesel engine shaft system under torsion during normal operation is simulated. Combined with the deformation performance of the structure under stress, the equivalent torsional stiffness of the complex shaft segment is calculated, and the stiffness index that fits the actual working condition is obtained.

[0100] Step S263: Replace or modify the corresponding stiffness in the torsional vibration coupling model using the equivalent torsional stiffness to obtain the modified stiffness.

[0101] Specifically, the equivalent torsional stiffness calculated using the finite element model is used to replace the original coarse stiffness parameter at the corresponding location in the torsional vibration coupling model, thus updating and adjusting the stiffness data for that region to obtain the corrected stiffness. This corrected stiffness more closely matches the actual structural characteristics.

[0102] This embodiment targets complex structures with non-uniform cross sections and transitional connections in the shaft system. A local finite element model is established based on the actual geometry. The equivalent torsional stiffness of the part is accurately solved by simulating the actual torsional load conditions. This model replaces the originally roughly estimated stiffness parameters in the coupled model, which can effectively eliminate the stiffness calculation error caused by the equivalent simplification method of regular cross sections. This makes the dynamic parameters at key locations more consistent with the actual mechanical properties of the components, thereby greatly improving the modeling accuracy of the shaft system torsional vibration coupled model.

[0103] In some embodiments, step S300, which involves inputting the engine excitation load spectrum into the torsional vibration coupling model and calculating the torsional vibration response parameters of each shaft system, includes steps S310 to S330.

[0104] Step S310: Convert the engine excitation load spectrum into external excitation torques acting on the corresponding rotational degrees of freedom in the torsional vibration coupling model.

[0105] Specifically, based on the engine excitation load spectrum and considering the actual position and working phase of different excitations on the shaft system, various original excitation forms are transformed into external excitation torques that can act on the corresponding rotational degrees of freedom of the torsional vibration coupling model, enabling various excitations under actual operating conditions to adapt to the model's operating rules. The engine excitation load spectrum can include cylinder combustion pressure excitation, reciprocating inertial force excitation, rotational inertial force excitation, valve train excitation, and speed and / or operating condition fluctuation excitation.

[0106] For example, the combustion excitation of the cylinders can be converted into a periodic external excitation torque acting on the corresponding rotational degree of freedom of the crankshaft, based on the firing order and crank phase of each cylinder; the load fluctuation of the accessories can also be converted into an external excitation torque acting on the corresponding rotational degree of freedom of the branch shaft system.

[0107] Step S320: Determine the torsional vibration response based on the coupled model of torsional vibration driven by external excitation torque.

[0108] Specifically, the converted external excitation torque is applied to the torsional vibration coupling model to drive the entire model to simulate the actual operating state of the diesel engine. This causes the main shaft system and each branch shaft system in the model to generate corresponding torsional motion and deformation under the excitation, thereby presenting the overall torsional vibration response state of the entire shaft system.

[0109] Step S330: Calculate the torsional vibration response parameters of each shaft system based on the torsional vibration response.

[0110] Specifically, based on the torsional vibration response state exhibited after the model's operation, various data are extracted and organized. The torsional angular displacement, torsional velocity, torsional torque, and torsional stress of the crankshaft system, camshaft system, and each key accessory branch shaft system are statistically analyzed. These data are then compiled into complete torsional vibration response parameters for each shaft system, visually representing the vibration performance of different shaft systems. The torsional vibration response parameters may include one or more of the following: torsional angular displacement, torsional velocity, torsional torque, and torsional stress of the crankshaft system, camshaft system, and key accessory branch shaft systems.

[0111] This embodiment first converts the engine excitation load spectrum, including cylinder combustion, inertial force, valve train, and operating condition fluctuations, into external excitation torques for each rotational degree of freedom of the adaptive model. Then, it uses these external excitation torques to drive the torsional vibration coupling model to simulate the actual operating conditions of the diesel engine and obtain the overall torsional vibration response. Finally, it extracts key response parameters such as torsional vibration angular displacement, torsional vibration velocity, torsional vibration torque, and torsional vibration stress of each shaft system. This not only enables accurate reproduction of the excitation conditions under real operating conditions in the simulation model and ensures that the excitation application position and action law are consistent with the actual operating state, but also allows for comprehensive and complete collection of multi-dimensional torsional vibration data of the main shaft system and each accessory branch shaft system.

[0112] In some embodiments, the step S400 of identifying the vibration risk of each shaft system based on the torsional vibration response parameters includes steps S410 to S420.

[0113] Step S410: Compare the torsional vibration response parameters of the crankshaft system, camshaft system, and key accessory branch shaft system with their respective safety criteria.

[0114] Specifically, safety criteria are set for the crankshaft system, camshaft system and key accessory branch shaft system, taking into account marine industry standards, enterprise design standards and fatigue performance requirements of component materials. Then, the response parameters of each shaft system, such as torsional vibration angular displacement, torsional vibration velocity, torsional vibration torque and torsional vibration stress obtained from simulation, are compared and verified item by item with the matching safety criteria.

[0115] Step S420: If the torsional vibration response parameters of any shaft system do not meet the corresponding safety criteria, identify the shaft systems with vibration risk.

[0116] Specifically, during the item-by-item comparison process, if any torsional vibration response parameter of a certain shafting system fails to meet the requirements of the corresponding safety criterion, it can be determined that the shafting system has a potential torsional vibration hazard, thus accurately identifying the specific shafting system with vibration risk. The safety criterion can be determined based on classification society regulations, enterprise design standards, material fatigue strength, test data, or engineering experience.

[0117] For example, for crankshaft and camshaft systems, it can be determined whether their torsional vibration stress exceeds the corresponding allowable stress, or whether the critical speed falls within the commonly used speed range of the diesel engine. For critical accessory branch shaft systems, it can be determined whether their maximum torsional vibration stress exceeds the allowable safety threshold corresponding to their material fatigue strength, or whether their torsional vibration angular displacement or alternating torque exceeds the allowable range. If the torsional vibration response parameters of any shaft system do not meet the corresponding safety criteria, the shaft system with vibration risk is identified.

[0118] This embodiment sets up exclusive safety criteria for different shaft systems based on marine industry standards, enterprise design standards, and fatigue performance requirements of component materials. It compares the various torsional vibration response parameters obtained from simulation with the corresponding safety criteria to locate shaft systems with potential torsional vibration hazards. This not only achieves full-coverage safety verification of crankshaft systems, camshaft systems, and various key accessory branch shaft systems, avoiding the problem of missed risk assessment, but also ensures that the vibration risk identification process is objective and reliable based on standardized judgment criteria, enabling rapid and accurate location of vibration hazards.

[0119] In some embodiments, step S400, which updates the torsional vibration coupling model according to the vibration risk of each shaft system to obtain the target torsional vibration coupling model, includes steps S430 to S460.

[0120] Step S430: Adjust the model parameters corresponding to the shaft system with vibration risk to obtain the adjusted model parameters.

[0121] Specifically, for shaft systems that have been identified as having vibration risks, the various model parameters corresponding to the shaft system are modified in a targeted manner, taking into account the structural characteristics of the shaft system and the causes of the vibration problem. The adjustable model parameters include equivalent moment of inertia, torsional stiffness, damping, and transmission-related parameters. The adjusted model parameters that meet the optimization requirements are obtained through reasonable adjustments.

[0122] For example, when a critical accessory branch shaft system is at risk of vibration, the adjusted model parameters can be obtained by reducing the equivalent inertia of its rotating components, adjusting the equivalent torsional stiffness of the transmission shaft section, or changing the branch damping parameters. For instance, considering high-strength materials like titanium alloys, compared to traditional steel, they can be made lighter while ensuring that critical rotating components such as impellers and transmission gears can withstand alternating torsional vibration loads without fracture fatigue failure. With the overall weight of the components reduced, the equivalent rotational inertia of the branch shaft system at risk of vibration decreases accordingly, and the inertial excitation torque generated during operation will significantly decrease. This effectively suppresses the torsional vibration amplitude of the branch shaft system and reduces the vibration energy transmitted to the main shaft system, thereby eliminating the shaft system's torsional vibration safety risk. Simultaneously, lightweight materials do not sacrifice structural strength for weight reduction and can withstand alternating torsional vibration loads for extended periods, meeting the reliability requirements for long-term continuous operation of marine diesel engines. Therefore, the materials of one or more critical rotating components in the vibration-risk branch shaft system (such as the impeller of a freshwater pump or the gear of a seawater pump) can be replaced from traditional steel-based materials to titanium alloys or other lightweight materials with high specific strength. For example, in cases where there is a vibration risk in the crankshaft or camshaft system, adjusted model parameters can be obtained by adjusting the stiffness of the corresponding shaft segments, damper parameters, or coupling parameters.

[0123] Step S440: Update the torsional vibration coupling model using the adjusted model parameters.

[0124] Specifically, the adjusted model parameters are used to replace the original parameters corresponding to the risk axis system in the torsional vibration coupling model. The torsional vibration coupling model is updated according to the original connection relationship and transmission constraints of each unit, so as to complete the replacement and adaptation of the parameters of the problem part without changing the overall model structure.

[0125] Step S450: Re-input the engine excitation load spectrum into the updated torsional vibration coupling model and recalculate the torsional vibration response parameters.

[0126] Specifically, the torsional vibration coupling model with updated parameters is reconnected to the complete engine excitation load spectrum, and the simulation calculation is performed again to simulate the actual operating conditions of the diesel engine, so as to obtain the various torsional vibration response parameters of all shaft systems.

[0127] Step S460: If the torsional vibration response parameters of each shaft system meet the corresponding safety criteria, the updated torsional vibration coupling model is determined as the target torsional vibration coupling model.

[0128] Specifically, the torsional vibration response parameters obtained from the new round of calculations are checked against the safety criteria corresponding to each shaft system. Once all parameters of the crankshaft system, camshaft system, and all key accessory branch shaft systems meet the safety requirements, the current model, which has undergone multiple updates, can be determined as the target torsional vibration coupling model.

[0129] This embodiment targets shaft systems identified as having vibration risks. It uses optimized parameters to locally update the torsional vibration coupling model, thereby determining a target torsional vibration coupling model. This model enables directional optimization iteration of high-risk shaft systems, allowing for simulation and optimization of structural parameters without altering the overall model architecture. This significantly reduces repetitive modeling workload and improves simulation optimization efficiency. Furthermore, multiple rounds of verification ensure that the optimized shaft system structure effectively avoids torsional vibration safety hazards. The result is a high-precision simulation model that closely matches engineering realities and meets ship operation safety requirements. This provides reliable technical support for the optimized design of marine diesel engine shaft systems, the development of vibration reduction schemes, and factory safety verification.

[0130] Please see Figure 3 , Figure 3The diagram shows a flowchart of a design method for a marine diesel engine shafting system. First, the main structural parameters of the marine diesel engine shafting system are obtained, including the geometric dimensions, moment of inertia, torsional stiffness, damping, material parameters, and transmission connections of the crankshaft system, camshaft system, and key accessory branch shafts such as freshwater pumps and seawater pumps. Based on these main structural parameters, a shafting layout diagram and a shafting equivalent parameter table are generated. The crankshaft system, camshaft system, and key accessory branch shafts are integrated into a torsional vibration coupling model, where the accessory branch shafts are coupled to the main shafting system as flexible subsystems with their own inertia, stiffness, and damping. The engine excitation load spectrum, such as cylinder combustion excitation, reciprocating and rotating inertial force excitation, valve train excitation, speed and operating condition fluctuation excitation, etc., are input into the torsional vibration coupling model to calculate the natural frequency, critical speed, torsional vibration mode shape, torsional angular displacement, torsional speed, torsional torque, torsional stress, and torsional amplitude of each shaft system. The calculation results are then compared with the corresponding safety criteria to determine whether the crankshaft system, camshaft system, and critical accessory branch shaft systems exceed the allowable values. If a vibration risk is identified, targeted model updates or design adjustments are made according to the shaft system where the risk is located. Finally, the adjusted parameters are re-substituted into the torsional vibration coupling model, and response calculations and safety checks are performed again until the torsional vibration response parameters of each shaft system meet the predetermined safety requirements. This yields the target torsional vibration coupling model and a shaft system design scheme that meets the safety margin requirements.

[0131] Secondly, embodiments of this application provide a design system for a marine diesel engine shafting system. Please refer to [link to relevant documentation]. Figure 4 ,include: The parameter acquisition module 401 is used to acquire the structural parameters of the marine diesel engine shaft system, which includes the crankshaft system, camshaft system and key accessory branch shaft system. Model building module 402 is used to build a torsional vibration coupling model based on structural parameters, wherein the key accessory branch shaft system is coupled to at least one of the crankshaft system and the camshaft system. The vibration response calculation module 403 is used to input the engine excitation load spectrum into the torsional vibration coupling model and calculate the torsional vibration response parameters of each shaft system. The optimization module 404 is used to identify the vibration risk of each shaft system based on the torsional vibration response parameters, and update the torsional vibration coupling model based on the vibration risk of each shaft system to obtain the target torsional vibration coupling model, so as to design the marine diesel engine shaft system based on the target torsional vibration coupling model.

[0132] Thirdly, embodiments of this application provide an electronic device. Please refer to... Figure 5The electronic device includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the method for constructing the torsional vibration model of the marine diesel engine shaft system in any of the aforementioned method embodiments. The electronic device can be an engineering computing workstation, a server, an industrial computer, a simulation computing platform, or a marine diesel engine design and analysis terminal.

[0133] Fourthly, embodiments of this application provide a computer-readable storage medium having a computer program stored thereon, the computer program being loaded by a processor to perform the steps of any of the methods described above.

[0134] In the embodiments of this application, the storage medium may be a magnetic disk, an optical disk, a read-only memory (ROM), or a random access memory (RAM), etc.

[0135] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0136] The design method, system, and electronic equipment for a marine diesel engine shafting system provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A design method for a marine diesel engine shafting system, characterized in that, Includes the following steps: Obtain the structural parameters of the marine diesel engine shafting system, which includes the crankshaft system, camshaft system, and key accessory branch shafting system; Based on the structural parameters, a torsional vibration coupling model is constructed; Input the engine excitation load spectrum into the torsional vibration coupling model and calculate the torsional vibration response parameters of each shaft system; The vibration risk of each shaft system is identified based on the torsional vibration response parameters, and the torsional vibration coupling model is updated based on the vibration risk of each shaft system to obtain the target torsional vibration coupling model, so as to design the marine diesel engine shaft system based on the target torsional vibration coupling model.

2. The design method for marine diesel engine shafting according to claim 1, characterized in that, Based on the structural parameters, a torsional vibration coupling model is constructed, including: The structural parameters are transformed to obtain shaft system modeling data that characterizes the shaft system connection relationship, rotational inertia distribution, torsional stiffness distribution and damping distribution; Based on the shaft system modeling data, determine the shaft system topology; Based on the aforementioned shaft system topology, determine the power transmission path between each shaft system; Establish a main shaft system model and a branch shaft system model along the power transmission path; Based on the transmission constraint relationship between the main shaft system model and the branch shaft system model, the torsional vibration coupling model is constructed.

3. The design method for marine diesel engine shafting according to claim 2, characterized in that, Based on the shaft system modeling data, the topological relationships of the shaft system are determined, including: Using the torque-transmitting connection relationship as the boundary, the crankshaft system, the camshaft system, and the key accessory branch shaft system are mapped into a shaft system topology with connection nodes and transmission edges; The connecting node represents the rotational degree of freedom in the shaft system, and the transmission edge represents the torque transmission relationship between adjacent rotational degrees of freedom.

4. The design method for marine diesel engine shafting according to claim 2, characterized in that, Establishing a main shaft system model and a branch shaft system model along the power transmission path includes: Based on the shaft system modeling data, determine the rotational inertia distribution, torsional stiffness distribution, and damping distribution in the crankshaft system and the camshaft system; The structure whose contribution is mainly due to rotational inertia is equivalent to rotational degrees of freedom, and the structure whose contribution is mainly due to torsional deformation is equivalent to the elastic transfer relationship connecting adjacent rotational degrees of freedom. Based on the rotational degrees of freedom, the elastic transmission relationship, and the damping distribution, the principal shaft system model is established.

5. The design method for marine diesel engine shafting according to claim 2, characterized in that, Establishing a main shaft system model and a branch shaft system model along the power transmission path includes: Based on the shaft system modeling data, determine the equivalent inertia, equivalent torsional stiffness, and equivalent damping of the key accessory branch shaft system; The key accessory branch shaft system is considered as a flexible subsystem with independent rotational degrees of freedom; The branch shaft system model is established based on the equivalent inertia, equivalent torsional stiffness, equivalent damping, and independent rotational degrees of freedom.

6. The design method for marine diesel engine shafting according to claim 2, characterized in that, Based on the transmission constraint relationship between the main shaft system model and the branch shaft system model, the torsional vibration coupling model is constructed, including: Determine the connection position between the key accessory branch shaft system and at least one of the crankshaft system and the camshaft system; Based on the connection position, transmission ratio, and transmission direction, determine the angular displacement constraint relationship and torque transmission relationship between the main shaft system model and the branch shaft system model; The angular displacement constraint relationship and the torque transmission relationship are introduced between the main shaft system model and the branch shaft system model to form the torsional vibration coupling model.

7. The design method for marine diesel engine shafting according to claim 6, characterized in that, The angular displacement constraint relationship and the torque transmission relationship are introduced between the main shaft system model and the branch shaft system model to form the torsional vibration coupling model, including: Based on the angular displacement constraint relationship, the rotational degrees of freedom in the branch shaft system model are mapped to the corresponding rotational degrees of freedom in the main shaft system model; Based on the torque transmission relationship, the equivalent inertial torque and / or equivalent elastic torque generated by the branch shaft system model are fed back to the main shaft system model; Based on the mapped rotational degrees of freedom and the feedback torque transmission relationship, the torsional vibration coupling model is formed.

8. The design method for marine diesel engine shafting according to claim 2, characterized in that, The method further includes: For shaft components with non-uniform cross sections or transitional connection structures, local stiffness correction is performed to obtain the corrected stiffness; Based on the corrected stiffness, the torsional vibration coupling model is constructed.

9. The design method for marine diesel engine shafting according to claim 8, characterized in that, The method of performing local stiffness correction on shaft system sections with non-uniform cross-sections or transitional connection structures to obtain corrected stiffness includes: A local finite element model is established based on the actual geometric structure of the shaft system to be corrected. Based on the local finite element model, the equivalent torsional stiffness of the shaft system to be corrected is calculated. The equivalent torsional stiffness is used to replace or modify the corresponding stiffness in the torsional vibration coupling model to obtain the modified stiffness.

10. The design method for a marine diesel engine shafting system according to any one of claims 1 to 9, characterized in that, Input the engine excitation load spectrum into the torsional vibration coupling model, and calculate the torsional vibration response parameters of each shaft system, including: The engine excitation load spectrum is converted into external excitation torques acting on the corresponding rotational degrees of freedom in the torsional vibration coupling model; Based on the external excitation torque driving the torsional vibration coupling model, the torsional vibration response is determined; Based on the torsional vibration response, the torsional vibration response parameters of each shaft system are calculated; The torsional vibration response parameters include one or more of the following: torsional angular displacement, torsional velocity, torsional torque, and torsional stress of the crankshaft system, the camshaft system, and the key accessory branch shaft system.

11. The design method for a marine diesel engine shafting system according to any one of claims 1 to 9, characterized in that, Identifying the vibration risk of each shaft system based on the aforementioned torsional vibration response parameters includes: The torsional vibration response parameters of the crankshaft system, the camshaft system, and the key accessory branch shaft system are compared with their respective safety criteria. If the torsional vibration response parameters of any shaft system do not meet the corresponding safety criteria, the shaft system with vibration risk is identified.

12. The design method for marine diesel engine shafting according to claim 11, characterized in that, The torsional vibration coupling model is updated based on the vibration risk of each shaft system to obtain the target torsional vibration coupling model, including: Adjust the model parameters corresponding to the shaft system with vibration risk to obtain the adjusted model parameters; The torsional vibration coupling model is updated using the adjusted model parameters. The engine excitation load spectrum was re-input into the updated torsional vibration coupling model, and the torsional vibration response parameters were recalculated. If the torsional vibration response parameters of each shaft system meet the corresponding safety criteria, the updated torsional vibration coupling model is determined as the target torsional vibration coupling model.

13. A design system for a marine diesel engine shafting system, characterized in that, include: The parameter acquisition module is used to acquire the structural parameters of the marine diesel engine shafting system, which includes the crankshaft system, camshaft system, and key accessory branch shafting system. The model building module is used to build a torsional vibration coupling model based on the structural parameters, wherein the key accessory branch shaft system is coupled to at least one of the crankshaft system and the camshaft system; The vibration response calculation module is used to input the engine excitation load spectrum into the torsional vibration coupling model and calculate the torsional vibration response parameters of each shaft system. An optimization module is used to identify the vibration risk of each shaft system based on the torsional vibration response parameters, and update the torsional vibration coupling model based on the vibration risk of each shaft system to obtain a target torsional vibration coupling model, so as to design the marine diesel engine shaft system based on the target torsional vibration coupling model.

14. An electronic device, characterized in that, It includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the method as described in any one of claims 1 to 12.

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