A method, apparatus, equipment, and storage medium for suppressing abnormal torsional vibration in a propulsion shaft system.

Abstract

This invention discloses a method, apparatus, device, and storage medium for suppressing abnormal torsional vibration in a propulsion shaft system, relating to the field of marine propulsion system technology. The method includes: matching the torsional natural frequency and torsional mode shape corresponding to the abnormal torsional vibration frequency of the propulsion shaft system; calculating the modal mass and modal damping ratio of the abnormal torsional vibration of the matching order, and calculating the support reactions at the aft and stern bearings and the forward and stern bearings; fitting the friction coefficients between the aft and stern bearings, the forward and stern bearings, and the propulsion shaft system; calculating the frictional excitation torque under the corresponding order torsional mode shape and the Taylor expansion coefficient corresponding to the frictional excitation torque based on the support reactions, friction coefficients, and the matched torsional mode shape; and installing a suppression device on the propulsion shaft system to generate electrical damping based on the matched torsional natural frequency, modal mass, modal damping ratio, and Taylor expansion coefficient to suppress abnormal torsional vibration. This application achieves accurate suppression of abnormal torsional vibration through precise design of the structural parameters of the suppression device.

Description

Technical Field

[0001] This application relates to the field of marine propulsion system technology, specifically to a method, device, equipment, and storage medium for suppressing abnormal torsional vibration in a propulsion shaft system. Background Technology

[0002] A ship's propulsion shafting system is a mechanical transmission system that connects the ship's power plant to the propeller. Its main function is to transmit the power and torque generated by the engine to the propeller, thereby propelling the ship forward.

[0003] During the operation of the propulsion shaft system, the frictional excitation generated by the water-lubricated bearing may induce abnormal torsional vibration, which in turn causes vibration noise and has an adverse effect on the smooth operation of the propulsion shaft system.

[0004] However, existing technologies lack effective measures to suppress abnormal torsional vibrations in propulsion shaft systems induced by friction excitation. This is because the underlying mechanisms are poorly understood, the specific conditions under which these vibrations occur, and their boundary ranges are not fully grasped. Furthermore, current methods require frequent on-site vibration data collection, making the process cumbersome. Summary of the Invention

[0005] This application provides a method, apparatus, device, and storage medium for suppressing abnormal torsional vibration in a propulsion shaft system. By precisely designing the structural parameters of the suppression device, abnormal torsional vibration can be accurately suppressed.

[0006] In a first aspect, embodiments of this application provide a method for suppressing abnormal torsional vibration in a propulsion shaft system, the method comprising:

[0007] Match the torsional natural frequency and torsional mode shape corresponding to the abnormal torsional vibration frequency of the propulsion shaft system;

[0008] Calculate the modal mass and modal damping ratio of the abnormal torsional vibration of the matching order, and calculate the support reaction forces at the stern and fore-stern bearings.

[0009] Fit the friction coefficients between the stern bearing, the fore-stern bearing and the propulsion shaft system;

[0010] Based on the support reaction force, friction coefficient, and matched torsional vibration mode, calculate the friction excitation torque under the corresponding order torsional vibration mode, as well as the Taylor expansion coefficient of the friction excitation torque;

[0011] Based on the matched torsional vibration natural frequency, modal mass, modal damping ratio, and Taylor expansion coefficient, a suppression device for generating electrical damping is installed on the propulsion shaft system to suppress abnormal torsional vibration.

[0012] In conjunction with the first aspect, in one embodiment, the suppression device includes a sleeve for fitting onto the propulsion shaft system, the sleeve having multiple piezoelectric ceramic plates electrically connected thereto, and a load resistor connected to one of the piezoelectric ceramic plates.

[0013] In conjunction with the first aspect, in one embodiment, the method of providing a suppression device for generating electrical damping on the propulsion shaft system based on the matched torsional natural frequency, modal mass, modal damping ratio, and Taylor expansion coefficient includes:

[0014] Set the structural parameters of the suppression device to satisfy:

[0015]

[0016] In the formula, ξ j For the matched modal damping ratio, γ 1,j M represents the Taylor expansion coefficients. j For the matched modal quality, ω j For the torsional vibration natural frequency to be matched, κ is the first electromechanical coupling coefficient, and Γ is the second electromechanical coupling coefficient;

[0017] Where κ and Γ satisfy:

[0018] κ=C p ω j R L ,

[0019] In the formula, R L For the load resistance, C p υ represents the total capacitance after all piezoelectric ceramic sheets are connected in parallel, and υ is the electromechanical third coupling coefficient.

[0020] Among them, υ and C p satisfy:

[0021]

[0022] In the formula, d 15 G is the piezoelectric coefficient of the piezoelectric ceramic material. p n is the shear modulus of the piezoelectric ceramic. p R represents the number of piezoelectric ceramic sheets. p h is the radius of the piezoelectric ceramic sheet bonding location. p L represents the thickness of the piezoelectric ceramic sheet. p1 and L p2 To suppress the distance between the tip and tip of the device and the center of the propeller, Let be the dielectric constant of the piezoelectric ceramic sheet, and α be the central angle corresponding to the width of each piezoelectric ceramic sheet.

[0023] In conjunction with the first aspect, in one embodiment, the coefficient of friction between the fitted stern bearing, the fore-stern bearing, and the propulsion shaft system includes:

[0024] According to the formula: The friction coefficient between the stern bearing and the propulsion shaft system after fitting;

[0025] In the formula, μ b μ is the coefficient of friction between the stern bearing and the propulsion shaft system. b,1 Let μ be the coefficient of dynamic friction between the stern bearing and the propulsion shaft system. b,0 Let a be the static friction coefficient between the stern bearing and the propulsion shaft system. b R is a constant. b ω is the outer radius of the shaft system at the stern bearing, ω is the relative angular velocity between the bearing shell and the shaft system surface, and sign() is the sign function;

[0026] According to the formula: Fit the friction coefficient between the fore-and-aft bearing and the propulsion shaft system;

[0027] In the formula, μ f μ is the coefficient of friction between the forward and stern bearings and the propulsion shaft system. f,1 Let μ be the coefficient of dynamic friction between the fore-and-aft bearing and the propulsion shaft system. f,0 Let a be the static friction coefficient between the fore-and-aft bearing and the propulsion shaft system. f R is a constant. f ω is the outer radius of the shaft system at the front and rear bearings, ω is the relative angular velocity between the bearing and the shaft system surface, and sign() is the sign function.

[0028] In conjunction with the first aspect, in one embodiment, the step of calculating the frictional excitation torque under the corresponding order torsional vibration mode, and the Taylor expansion coefficient corresponding to the frictional excitation torque, based on the support reaction force, friction coefficient, and matched torsional vibration mode, includes:

[0029] According to the formula:

[0030]

[0031] Calculate the frictional excitation torque under the corresponding order mode shape;

[0032] In the formula, F j This refers to the frictional excitation torque under the corresponding torsional vibration mode. and N represents the mode shape values ​​at the aft and forward stern bearings, respectively, under the corresponding torsional vibration mode shapes. b and N f R represents the support reaction force at the aft and forward stern bearings, respectively. b and R fLet Ω be the outer radius at the stern and fore-stern bearings of the shaft system, respectively, and q be the rotational speed of the shaft system. j (t) represents the torsional displacement in the coordinate system of the corresponding torsional vibration mode;

[0033] According to the formula: Taylor expansion of the friction excitation torque;

[0034] In the formula, γ 0,j γ 1,j γ 2,j γ 3,j The coefficients of the Taylor expansion;

[0035] Where, γ 1,j Represented as:

[0036]

[0037] In conjunction with the first aspect, in one embodiment, the matching of the torsional natural frequency and mode shape corresponding to the abnormal torsional vibration frequency of the propulsion shaft system includes:

[0038] Determine the abnormal torsional vibration frequency of the propulsion shaft system;

[0039] A torsional vibration analysis model of the propulsion shaft system was established, and the torsional natural frequencies under multiple orders of the torsional vibration analysis model were obtained.

[0040] Determine the torsional natural frequency of the order closest to the abnormal torsional vibration frequency, and determine the torsional mode shape of the corresponding order.

[0041] In conjunction with the first aspect, in one implementation, it further includes:

[0042] The torsional vibration modes of abnormal torsional vibrations are normalized according to the maximum absolute value.

[0043] Secondly, embodiments of this application provide a propulsion shaft abnormal torsional vibration suppression device, the propulsion shaft abnormal torsional vibration suppression device comprising:

[0044] The calculation module is used for:

[0045] Match the torsional natural frequency and torsional mode shape corresponding to the abnormal torsional vibration frequency of the propulsion shaft system;

[0046] Calculate the modal mass and modal damping ratio of the abnormal torsional vibration of the matching order, and calculate the support reaction forces at the stern and fore-stern bearings.

[0047] Fit the friction coefficients between the stern bearing, the fore-stern bearing and the propulsion shaft system;

[0048] Based on the support reaction force, friction coefficient, and matched torsional vibration mode, calculate the friction excitation torque under the corresponding order torsional vibration mode, as well as the Taylor expansion coefficient of the friction excitation torque;

[0049] The module is configured to install a suppression device on the propulsion shaft to generate electrical damping, based on the matched torsional vibration natural frequency, modal mass, modal damping ratio, and Taylor expansion coefficient, in order to suppress abnormal torsional vibration.

[0050] Thirdly, embodiments of this application provide a propulsion shaft abnormal torsional vibration suppression device, the propulsion shaft abnormal torsional vibration suppression device including a processor, a memory, and a propulsion shaft abnormal torsional vibration suppression program stored in the memory and executable by the processor, wherein when the propulsion shaft abnormal torsional vibration suppression program is executed by the processor, the steps of the above-described propulsion shaft abnormal torsional vibration suppression method are implemented.

[0051] Fourthly, a computer-readable storage medium storing a propulsion shaft abnormal torsional vibration suppression program, wherein when the propulsion shaft abnormal torsional vibration suppression program is executed by a processor, it implements the steps of the above-described propulsion shaft abnormal torsional vibration suppression method.

[0052] The beneficial effects of the technical solutions provided in this application include at least the following:

[0053] The method for suppressing abnormal torsional vibration in the propulsion shaft system in this application involves: matching the torsional natural frequency and torsional mode shape corresponding to the abnormal torsional vibration frequency of the propulsion shaft system; calculating the modal mass and modal damping ratio of the abnormal torsional vibration of the matching order, and calculating the support reaction forces at the aft and stern bearings and the fore and stern bearings; fitting the friction coefficients between the aft and stern bearings, the fore and stern bearings and the propulsion shaft system; calculating the friction excitation torque under the corresponding order torsional vibration mode shape and the Taylor expansion coefficient corresponding to the friction excitation torque based on the support reaction force, friction coefficient and the matched torsional vibration mode shape; and setting a suppression device for generating electrical damping on the propulsion shaft system based on the matched torsional natural frequency, modal mass, modal damping ratio and Taylor expansion coefficient to suppress abnormal torsional vibration.

[0054] Therefore, this application has obtained a critical discrimination formula for eliminating abnormal torsional vibration through detailed dynamic theory derivation. By precisely designing the structural parameters of the suppression device to meet the requirements of the critical discrimination formula, abnormal torsional vibration can be accurately suppressed. Attached Figure Description

[0055] Figure 1 This is a schematic flowchart of an embodiment of the method for suppressing abnormal torsional vibration in the propulsion shaft system according to this application;

[0056] Figure 2 This is a schematic diagram of the installation of the suppression device in this application;

[0057] Figure 3 This is a schematic diagram of the structure of the suppression device in this application;

[0058] Figure 4 This is a schematic diagram of the structural dimensions of the suppression device in this application;

[0059] Figure 5 This is a simplified diagram of the propulsion shaft system for this application;

[0060] Figure 6 The above are the time-domain and frequency-domain plots of the abnormal torsional vibration of the propulsion shaft system in Embodiment 1 of this application. Figure 6 (a) is the time-domain curve. Figure 6 (b) is a frequency domain curve;

[0061] Figure 7 This is a diagram showing the suppression effect after installing the suppression device in Embodiment 1 of this application. Figure 7 (a) is the time-domain curve. Figure 7 (b) is a frequency domain curve;

[0062] Figure 8 The above are the time-domain and frequency-domain plots of the abnormal torsional vibration of the propulsion shaft system in Embodiment 2 of this application. Figure 8 (a) is the time-domain curve. Figure 8 (b) is a frequency domain curve;

[0063] Figure 9 This is a diagram showing the suppression effect after installing the suppression device in Embodiment 2 of this application. Figure 9 (a) is the time-domain curve. Figure 9 (b) is a frequency domain curve;

[0064] Figure 10 This is a structural block diagram of an embodiment of the propulsion shaft abnormal torsional vibration suppression device of this application;

[0065] Figure 11 This is a schematic diagram of the hardware structure of the propulsion shaft abnormal torsional vibration suppression device involved in the embodiments of this application. Detailed Implementation

[0066] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0067] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0068] In a first aspect, embodiments of this application provide a method for suppressing abnormal torsional vibration in a propulsion shaft system.

[0069] In one embodiment, reference is made to Figure 1 , Figure 1 This is a schematic flowchart of an embodiment of the method for suppressing abnormal torsional vibration in a propulsion shaft system according to this application. Figure 1 As shown, the methods for suppressing abnormal torsional vibration in the propulsion shaft system include:

[0070] S1. Match the torsional natural frequency and torsional mode shape corresponding to the abnormal torsional vibration frequency of the propulsion shaft system;

[0071] Specifically, step S1 includes:

[0072] S11. Determine the abnormal torsional vibration frequency of the propulsion shaft system;

[0073] S12. Establish a torsional vibration analysis model for the propulsion shaft system and obtain the torsional natural frequencies under multiple orders of the torsional vibration analysis model.

[0074] S13. Determine the torsional natural frequency of the order closest to the abnormal torsional vibration frequency, and determine the torsional mode shape of the corresponding order.

[0075] This embodiment utilizes finite element method (FEM) software to establish a torsional vibration analysis model of the propulsion shaft system. Based on the FEM model, the torsional vibration natural frequencies and mode shapes of the propulsion shaft system are calculated, and then the order of the torsional vibration natural frequencies to which the abnormal torsional vibration belongs is analyzed. Preferably, the torsional vibration mode shapes that cause abnormal vibration can also be normalized using the maximum absolute value.

[0076] S2. Calculate the modal mass and modal damping ratio of the abnormal torsional vibration of the matching order, and calculate the support reaction forces at the stern and fore-stern bearings.

[0077] First, obtain the modal mass of the torsional vibration mode that is experiencing abnormal vibration. Suppose that the j-th order torsional vibration mode is experiencing abnormal vibration, its modal mass can be obtained directly in finite element software such as ANSYS, or it can be obtained by combining the mass matrix M with the mode shape of the abnormal vibration. After exporting, calculate using the following formula:

[0078]

[0079] In the formula, This represents the normalized j-th order torsional vibration mode shape. for The transpose of the matrix, M j Let be the modal mass of the j-th order torsional vibration.

[0080] Then, obtain the modal damping ratio of the j-th torsional vibration mode of the propulsion shaft system. The modal damping ratio can be obtained through modal experiments. If it is difficult to conduct modal experiments on site, an empirical value of 0.01 to 0.1 can be used.

[0081] Finally, the support reaction force N at the aft and forward stern bearings was calculated based on the finite element model. b and N f .

[0082] S3, the friction coefficient between the stern bearing, the fore-stern bearing and the propulsion shaft system;

[0083] The coefficient of friction μ between the stern bearing and the shaft system at different speeds is provided by the manufacturer or measured experimentally. b μ is fitted using the following exponential function. b,0 μ b,1 a b Three coefficients:

[0084]

[0085] In the formula, μ b μ is the coefficient of friction between the stern bearing and the propulsion shaft system. b,1 Let μ be the coefficient of dynamic friction between the stern bearing and the propulsion shaft system. b,0 Let a be the static friction coefficient between the stern bearing and the propulsion shaft system. b R is a constant. b ω is the outer radius of the shaft system at the stern bearing, ω is the relative angular velocity between the bearing shell and the propulsion shaft surface, and sign() is the sign function.

[0086] Similarly, the coefficient of friction μ between the fore and stern bearings and the shaft system at different speeds is provided by the manufacturer or measured experimentally. f μ is fitted using the following exponential function. f,0 μ f,1 a f Three coefficients:

[0087]

[0088] In the formula, μ f μ is the coefficient of friction between the forward and stern bearings and the propulsion shaft system. f,1 Let μ be the coefficient of dynamic friction between the fore-and-aft bearing and the propulsion shaft system. f,0 Let a be the static friction coefficient between the fore-and-aft bearing and the propulsion shaft system. f R is a constant. f ω is the outer radius of the shaft system at the front and rear bearings, ω is the relative angular velocity between the bearing shell and the propulsion shaft surface, and sign() is the sign function.

[0089] It is worth noting that this embodiment only considers two water-lubricated bearings. For propulsion shaft systems with three or more water-lubricated bearings, the number of bearings can be expanded to multiple bearings according to step S3.

[0090] S4. Based on the support reaction force, friction coefficient, and matched torsional vibration mode, calculate the friction excitation torque under the corresponding order torsional vibration mode, and the Taylor expansion coefficient corresponding to the friction excitation torque.

[0091] Specifically, using the support reaction force and friction coefficient obtained above, combined with the obtained normalized j-th order mode shape, the frictional excitation torque F of the stern bearing and propulsion shaft system under the j-th order mode shape is calculated. j :

[0092]

[0093] In the formula, F j The frictional excitation torque is the torque in the j-th mode. and N represents the mode shape values ​​of the j-th torsional vibration mode located at the aft and forward stern bearings, respectively. b and N f R represents the support reaction force at the aft and forward stern bearings, respectively. b and R f Let Ω be the outer radius at the aft and forward stern bearings of the propulsion shaft, respectively, and q be the rotational speed of the propulsion shaft. j (t) represents the torsional displacement in the coordinate system of the j-th torsional vibration mode.

[0094] Then, F j Taylor expansion:

[0095]

[0096] In the formula, γ 0,j γ 1,j γ 2,j γ 3,j Let be the coefficients of the Taylor expansion, where γ 1,j It can be represented as:

[0097]

[0098] It is worth noting that, considering the weighting and the relationship with the parameters involved in the frictional excitation torque, the Taylor expansion coefficients mainly consider γ. 1,j Since the torsional vibration amplitude of the propulsion shaft system is very small, most cases in engineering can be attributed to the first equation (6).

[0099] S5. Based on the matched torsional vibration natural frequency, modal mass, modal damping ratio and Taylor expansion coefficient, a suppression device for generating electrical damping is installed on the propulsion shaft system to suppress abnormal torsional vibration.

[0100] Design on the shaft, such as Figure 2 The suppression device is shown. There are no strict requirements for its installation location, but installing it at locations of drastic mode shape changes will make it easier to suppress that order of aberrant torsional vibration. If multiple torsional modes are experiencing aberrant vibration, a suppression device can be installed at each location of drastic mode shape change in the aberrant torsional vibration mode.

[0101] The detailed structure of the suppression device is as follows: Figure 3 As shown, it consists of two half-sleeves, n p A piezoelectric ceramic sheet, a load resistor R L It consists of multiple bolts and nuts. The two sleeve halves are secured to the shaft by multiple bolts and nuts (e.g., 6), thus generating the same torsional vibration as the shaft system. Piezoelectric ceramic sheets are bonded to the sleeves and connected in parallel, operating at d... 15 In this mode.

[0102] The working principle of this device is as follows: When the sleeve follows the torsional vibration of the rotating shaft, it drives the piezoelectric ceramic plate to generate electricity, which produces an electrical damping effect. This is achieved by designing a load resistor R... L This can be achieved by generating electrical damping that can eliminate abnormal torsional vibration.

[0103] The structural parameters to be designed for the suppression device include: length L p2 -L p1 , placement [L p1 L p2 The number of piezoelectric ceramic sheets n p piezoelectric ceramic sheet thickness h p The central angle α corresponding to the piezoelectric ceramic, and the outer radius R of the sleeve. p Load resistance R L And the selection of piezoelectric ceramic materials.

[0104] By rationally designing the structural parameters of the suppression device, the critical discrimination formula (7) can be made to make the abnormal vibration of the torsional mode disappear.

[0105]

[0106] In the formula, ξ j Let γ be the modal damping ratio of the j-th order abnormal torsional vibration. 1,j M represents the Taylor expansion coefficients. j Let ω be the modal mass of the j-th order anomalous torsional vibration. jLet be the natural frequency of the j-th order abnormal torsional vibration, and κ and Γ be the first and second electromechanical coupling coefficients, respectively. Their values ​​are related to the structural design parameters of the suppression device, and can be specifically expressed as:

[0107]

[0108] In the formula, R L For the load resistance, C p The capacitance is the total capacitance of all piezoelectric ceramic sheets connected in parallel, and υ is the electromechanical third coupling coefficient; where υ and C p The expression is as follows:

[0109]

[0110] In the formula, d 15 G is the piezoelectric coefficient of the piezoelectric ceramic material. p n is the shear modulus of the piezoelectric ceramic. p R represents the number of piezoelectric ceramic sheets. p h is the radius of the piezoelectric ceramic sheet bonding location. p L represents the thickness of the piezoelectric ceramic sheet. p1 and L p2 To suppress the distance between the tip and tip of the device and the center of the propeller, Let be the dielectric constant of the piezoelectric ceramic sheet, and 'a' be the central angle corresponding to the width of each piezoelectric ceramic sheet (e.g., ...). Figure 4 (As shown).

[0111] It is worth noting that in the suppression device, the piezoelectric ceramic sheets can be connected in series, in parallel, or in a combination of series and parallel; only the total capacitance C needs to be modified accordingly. p That's all.

[0112] The critical discrimination formula (7) is derived through rigorous dynamic model derivation, thus achieving very high control accuracy. In practical applications, to improve the suppression effect, a safety factor of 1.2 can be used, therefore formula (7) can be transformed into:

[0113]

[0114] The derivation of the critical discrimination formula (7) is as follows:

[0115] like Figure 2 As shown, the distances from the beginning and end of the suppression device to the center of the propeller are denoted as L. p1 and L p2 Therefore, the length of each set of piezoelectric ceramic sheets is L. p2 -L p1 .like Figure 4 As shown, the thickness of the piezoelectric sheet is h. p The central angle corresponding to its width is α, and the radius of the sleeve containing the piezoelectric element is R. pTherefore, the width of each group of piezoelectric elements is R. p α, the number of piezoelectric elements is n p .

[0116] Compared to the entire propulsion shaft system, the suppression device is very light, therefore it has almost no effect on the shaft system's torsional vibration natural frequency and mode shape. Considering this suppression device, assuming that the j-th torsional mode produces abnormal vibration, the vibration differential equation for this mode is established as follows:

[0117]

[0118] In the formula, M j Let q be the modal mass of the j-th order torsional vibration. j (t) represents the torsional displacement in the coordinate system of the j-th torsional vibration mode, ξ j For the modal damping of the j-th order torsional vibration, ω j γ is the natural frequency of the j-th order torsional vibration. 0,j γ 1,j γ 2,j γ 3,j V is the Taylor expansion coefficient of the modal excitation torque, V is the output voltage of the piezoelectric ceramic sheet, υ is the third electromechanical coupling coefficient, and C is the third electromechanical coupling coefficient. p R is the total capacitance of the piezoelectric ceramic sheets connected in parallel. L This is the load resistance.

[0119] To make equation (11) dimensionless, the following variables are introduced:

[0120]

[0121] In the formula, q0 is a constant.

[0122] Substituting equation (12) into equation (11), we get:

[0123]

[0124] In the formula, and These are the dimensionless torsional displacement and output voltage, β. 0,j ,β 1,j ,β 2,j ,β 3,j κ,Γ are dimensionless coefficients, which can be expressed as:

[0125]

[0126] By solving equation (13) using the perturbation method, the critical discrimination formula (7) for the occurrence of abnormal vibrations in the system can be obtained.

[0127] The following two specific examples will further illustrate the steps described above:

[0128] Example 1:

[0129] Suppose that a ship's propulsion shafting system can be simplified as follows: Figure 5 The shaft segment model is shown in Table 1. Detailed geometric dimensions of each shaft segment are shown in Table 1. In this table, L represents the length of the shaft segment, Ro represents the outer radius of the shaft segment, and Ri represents its inner radius. The extreme moment of inertia of the propeller is 10000 kg·m. 2 The moment of inertia of the driving end of the high-elastic clutch is 8000 kg.m. 2 The operating speed is 30 rpm.

[0130] Table 1. Dimensions of each section of the shaft system (m)

[0131]

[0132] The propulsion shaft system experienced abnormal torsional vibration, and the time-domain and frequency-domain results of the torsional vibration are as follows: Figure 6 As shown, the fundamental frequency and its harmonics, characterized by 71.6 Hz, can be observed in the vibration spectrum. Therefore, it can be confirmed that the abnormal torsional vibration frequency generated by the propulsion shaft system is 71.6 Hz. Next, the abnormal vibration is suppressed according to the method and process proposed in this application.

[0133] (1) A finite element model of the torsional vibration of the propulsion shaft system was established, and its first few torsional vibration natural frequencies were obtained, as shown in Table 2. The table shows that the second torsional vibration natural frequency is very close to the abnormal vibration frequency, therefore it can be determined that the propulsion shaft system experienced abnormal vibration in the second torsional mode. The second mode shape was normalized.

[0134] Table 2. Natural frequencies of torsional vibration (ω in rad / s)

[0135] variable <![CDATA[ω1]]> <![CDATA[ω2]]> <![CDATA[ω3]]> <![CDATA[ω4]]> <![CDATA[ω5]]> value 63.3Hz 71.7Hz 191.1Hz 205.5Hz 284.7Hz

[0136] (2) Solve for the modal mass, the damping ratio of the second-order torsional vibration and the reaction forces of the front and rear stern bearings respectively. The calculation results are shown in Table 3.

[0137] Table 3 Modal mass, modal damping, and fore and aft bearing support reactions

[0138] variable <![CDATA[M2]]> <![CDATA[ξ2]]> <![CDATA[N b ]]> <![CDATA[N f ]]> value 69.8 0.0095 41036N 29858N

[0139] (3) The friction coefficient provided by the manufacturer was fitted to obtain μ b,0 μ b,1 a b μ f,0 μ f,1 a f The six coefficients are shown in Table 4.

[0140] Table 4 shows the fitted friction coefficient values.

[0141] variable <![CDATA[μ b,0 ]]> <![CDATA[μ b,1 ]]> <![CDATA[a b ]]> <![CDATA[μ f,0 ]]> <![CDATA[μ f,1 ]]> <![CDATA[a f ]]> Fitted values 0.9 0.1 2 0.9 0.1 2

[0142] (4) Using the steps described above, the coefficient γ can be obtained. 1,2 and As shown in Table 5.

[0143] Table 5 Coefficient γ 1,2 and Value

[0144]

[0145] (5) Design of the suppression device. The structural parameters of the design are shown in Table 6. The piezoelectric sheet is arranged between the thrust bearing and the high-elasticity element (the 5th shaft segment).

[0146] Table 6 Structural parameters of the design

[0147]

[0148] The design parameters in Table 6 can be used to calculate... And after being superimposed with ξ2 according to the critical discrimination formula (7), and then with The comparison results are shown in Table 7. It can be seen that the design results satisfy the critical discrimination formula (7), and the design results can effectively suppress abnormal torsional vibration.

[0149] Table 7 Verification Values

[0150]

[0151] To verify the correctness of the method proposed in this application, a nonlinear dynamic modeling and simulation were performed on the propulsion shaft system after the installation of the suppression device to study its nonlinear response under frictional excitation. The calculation results are as follows: Figure 7 As shown, the time-domain curve eventually decays to zero, and the frequency spectrum also shows that there are no abnormal vibration frequencies in the response. Therefore, the simulation results prove the effectiveness of the method proposed in this application.

[0152] Example 2:

[0153] Still with Figure 5 Taking the propulsion shaft system shown as an example, assuming its operating speed is 20 rpm, since the damping of each torsional vibration mode of the shaft system has changed, the torsional vibration mode that produces abnormal vibration has also changed.

[0154] Simulation analysis of the propulsion shaft system was performed, and the torsional vibration time-domain and frequency-domain results are as follows: Figure 8 As shown, the fundamental frequency and its harmonics, characterized by 205.6 Hz, can be seen in the vibration spectrum. Therefore, it can be confirmed that the frequency causing the abnormal torsional vibration is 205.6 Hz. Next, the abnormal vibration is suppressed according to the method and process proposed in this application.

[0155] (1) A finite element model of the torsional vibration of the propulsion shaft system was established, and its first few torsional vibration natural frequencies were obtained, as shown in Table 8. The table shows that the fourth torsional vibration natural frequency is very close to the abnormal vibration frequency, therefore it can be determined that the propulsion shaft system experienced abnormal vibration in the fourth torsional vibration mode. The fourth mode shape was normalized.

[0156] Table 8. Natural frequencies of torsional vibration (ω in rad / s)

[0157] variable <![CDATA[ω1]]> <![CDATA[ω2]]> <![CDATA[ω3]]> <![CDATA[ω4]]> <![CDATA[ω5]]> value 63.3Hz 71.7Hz 191.1Hz 205.5Hz 284.7Hz

[0158] (2) Solve for the modal mass, the damping ratio of the fourth-order torsional vibration and the reaction forces of the front and rear stern bearings respectively. The calculation results are shown in Table 9.

[0159] Table 9 Modal mass, modal damping, and fore and aft stern bearing support reactions

[0160] variable <![CDATA[M4]]> <![CDATA[ξ4]]> <![CDATA[N b ]]> <![CDATA[N f ]]> value 72.5 0.004 41036N 29858N

[0161] (3) The friction coefficient provided by the manufacturer was fitted to obtain μ b,0 μ b,1 a b μ f,0 μ f,1 a f The six coefficients are shown in Table 10.

[0162] Table 10 shows the fitted friction coefficient values.

[0163] variable <![CDATA[μ b,0 ]]> <![CDATA[μ b,1 ]]> <![CDATA[a b ]]> <![CDATA[μ f,0 ]]> <![CDATA[μ f,1 ]]> <![CDATA[a f ]]> Fitted values 0.9 0.1 2 0.9 0.1 2

[0164] (4) Using the steps described above, the coefficient γ can be obtained. 1,4 and As shown in Table 11.

[0165] Table 11 Coefficient γ 1,4 and Value

[0166]

[0167] (5) Design of the suppression device. The structural parameters of the design are shown in Table 12. The piezoelectric sheet is arranged between the thrust bearing and the high-elasticity element (the 5th shaft segment).

[0168] Table 12 Structural parameters of the design

[0169]

[0170] The design parameters in Table 11 can be used to calculate... And after being superimposed with ξ4 according to the critical discrimination formula (7), and then with The comparison results are shown in Table 13. It can be seen that the design results satisfy the critical discrimination formula (7), and the design results can effectively suppress abnormal torsional vibration.

[0171] Table 13 Verification Values

[0172]

[0173] To verify the correctness of the method proposed in this application, a nonlinear dynamic modeling and simulation were performed on the propulsion shaft system after the installation of the suppression device to study its nonlinear response under frictional excitation. The calculation results are as follows: Figure 9 As shown, the time-domain curve eventually decays to zero, and the frequency spectrum also shows that there are no abnormal vibration frequencies in the response. Therefore, the simulation results prove the effectiveness of the method proposed in this application.

[0174] In summary, the method for suppressing abnormal torsional vibration in the propulsion shaft system in this application involves: matching the torsional natural frequency and torsional mode shape corresponding to the abnormal torsional vibration frequency of the propulsion shaft system; calculating the modal mass and modal damping ratio of the abnormal torsional vibration of the matching order, and calculating the support reaction forces at the aft and stern bearings and the fore and stern bearings; fitting the friction coefficients between the aft and stern bearings, the fore and stern bearings and the propulsion shaft system; calculating the friction excitation torque under the corresponding order torsional vibration mode shape and the Taylor expansion coefficient corresponding to the friction excitation torque based on the support reaction force, friction coefficient and the matched torsional vibration mode shape; and setting a suppression device for generating electrical damping on the propulsion shaft system based on the matched torsional natural frequency, modal mass, modal damping ratio and Taylor expansion coefficient to suppress abnormal torsional vibration.

[0175] Therefore, this application has obtained a critical discrimination formula for eliminating abnormal torsional vibration through detailed dynamic theory derivation. By precisely designing the structural parameters of the suppression device to meet the requirements of the critical discrimination formula, abnormal torsional vibration can be accurately suppressed.

[0176] Secondly, embodiments of this application also provide a device for suppressing abnormal torsional vibration in a propulsion shaft system.

[0177] In one embodiment, reference is made to Figure 10 , Figure 10 This is a functional module diagram of an embodiment of the propulsion shaft abnormal torsional vibration suppression device of this application. Figure 10 As shown, the abnormal torsional vibration suppression device for the propulsion shaft system includes a calculation module and a setting module.

[0178] The calculation module is used for:

[0179] Match the torsional natural frequency and torsional mode shape corresponding to the abnormal torsional vibration frequency of the propulsion shaft system;

[0180] Calculate the modal mass and modal damping ratio of the abnormal torsional vibration of the matching order, and calculate the support reaction forces at the stern and fore-stern bearings.

[0181] Fit the friction coefficients between the stern bearing, the fore-stern bearing and the propulsion shaft system;

[0182] Based on the support reaction force, friction coefficient, and matched torsional vibration mode, calculate the friction excitation torque under the corresponding order torsional vibration mode, as well as the Taylor expansion coefficient of the friction excitation torque;

[0183] The module is configured to install a suppression device on the propulsion shaft to generate electrical damping, based on the matched torsional vibration natural frequency, modal mass, modal damping ratio, and Taylor expansion coefficient, in order to suppress abnormal torsional vibration.

[0184] In a further embodiment, the suppression device includes a sleeve for fitting onto the propulsion shaft system, the sleeve having multiple piezoelectric ceramic plates electrically connected to it, and a load resistor connected to one of the piezoelectric ceramic plates.

[0185] Further, in one embodiment, the setting module, based on the matched torsional natural frequency, modal mass, modal damping ratio, and Taylor expansion coefficient, sets a suppression device for generating electrical damping on the propulsion shaft system, including:

[0186] Set the structural parameters of the suppression device to satisfy:

[0187]

[0188] In the formula, ξ j For the matched modal damping ratio, γ 1,j M represents the Taylor expansion coefficients. j For the matched modal quality, ω j For the torsional vibration natural frequency to be matched, κ is the first electromechanical coupling coefficient, and Γ is the second electromechanical coupling coefficient;

[0189] Where κ and Γ satisfy:

[0190] κ=C p ω j R L ,

[0191] In the formula, R L For the load resistance, C p υ represents the total capacitance after all piezoelectric ceramic sheets are connected in parallel, and υ is the electromechanical third coupling coefficient.

[0192] Among them, υ and C p satisfy:

[0193]

[0194] In the formula, d 15 G is the piezoelectric coefficient of the piezoelectric ceramic material. p n is the shear modulus of the piezoelectric ceramic. p R represents the number of piezoelectric ceramic sheets. p h is the radius of the piezoelectric ceramic sheet bonding location. p L represents the thickness of the piezoelectric ceramic sheet. p1 and L p2 To suppress the distance between the tip and tip of the device and the center of the propeller, Let be the dielectric constant of the piezoelectric ceramic sheet, and α be the central angle corresponding to the width of each piezoelectric ceramic sheet.

[0195] Further, in one embodiment, the calculation module fits the friction coefficients between the stern bearing, the fore-stern bearing, and the propulsion shaft system, including:

[0196] According to the formula: The friction coefficient between the stern bearing and the propulsion shaft system after fitting;

[0197] In the formula, μ b μ is the coefficient of friction between the stern bearing and the propulsion shaft system. b,1 Let μ be the coefficient of dynamic friction between the stern bearing and the propulsion shaft system. b,0 Let a be the static friction coefficient between the stern bearing and the propulsion shaft system. b R is a constant. b ω is the outer radius of the shaft system at the stern bearing, ω is the relative angular velocity between the bearing shell and the shaft system surface, and sign() is the sign function;

[0198] According to the formula: Fit the friction coefficient between the fore-and-aft bearing and the propulsion shaft system;

[0199] In the formula, μ f μ is the coefficient of friction between the forward and stern bearings and the propulsion shaft system. f,1 Let μ be the coefficient of dynamic friction between the fore-and-aft bearing and the propulsion shaft system. f,0 Let a be the static friction coefficient between the fore-and-aft bearing and the propulsion shaft system. f R is a constant. f ω is the outer radius of the shaft system at the front and rear bearings, ω is the relative angular velocity between the bearing and the shaft system surface, and sign() is the sign function.

[0200] Further, in one embodiment, the calculation module calculates the frictional excitation torque under the corresponding order torsional vibration mode and the Taylor expansion coefficient corresponding to the frictional excitation torque based on the support reaction force, friction coefficient, and matched torsional vibration mode, including:

[0201] According to the formula:

[0202]

[0203] Calculate the frictional excitation torque under the corresponding order mode shape;

[0204] In the formula, F j This refers to the frictional excitation torque under the corresponding torsional vibration mode. and N represents the mode shape values ​​at the aft and forward stern bearings, respectively, under the corresponding torsional vibration mode shapes. b and N f R represents the support reaction force at the aft and forward stern bearings, respectively. b and R f Let Ω be the outer radius at the stern and fore-stern bearings of the shaft system, respectively, and q be the rotational speed of the shaft system. j (t) represents the torsional displacement in the coordinate system of the corresponding torsional vibration mode;

[0205] According to the formula: Taylor expansion of the friction excitation torque;

[0206] In the formula, γ 0,j γ 1,j γ 2,j γ 3,j The coefficients of the Taylor expansion;

[0207] Where, γ 1,j Represented as:

[0208]

[0209] Further, in one embodiment, the calculation module matches the torsional natural frequency and mode shape corresponding to the abnormal torsional vibration frequency of the propulsion shaft system, including:

[0210] Determine the abnormal torsional vibration frequency of the propulsion shaft system;

[0211] A torsional vibration analysis model of the propulsion shaft system was established, and the torsional natural frequencies under multiple orders of the torsional vibration analysis model were obtained.

[0212] Determine the torsional natural frequency of the order closest to the abnormal torsional vibration frequency, and determine the torsional mode shape of the corresponding order.

[0213] Furthermore, in one embodiment, the computing module is also used for:

[0214] The torsional vibration modes of abnormal torsional vibrations are normalized according to the maximum absolute value.

[0215] The functions of each module in the aforementioned propulsion shaft abnormal torsional vibration suppression device correspond to the steps in the aforementioned propulsion shaft abnormal torsional vibration suppression method embodiment, and their functions and implementation processes will not be described in detail here.

[0216] Thirdly, this application provides a propulsion shaft abnormal torsional vibration suppression device, which can be a personal computer (PC), laptop computer, server or other device with data processing function.

[0217] Reference Figure 11 , Figure 11 This is a schematic diagram of the hardware structure of the propulsion shaft abnormal torsional vibration suppression device involved in the embodiments of this application. In this embodiment, the propulsion shaft abnormal torsional vibration suppression device may include a processor, a memory, a communication interface, and a communication bus.

[0218] The communication bus can be of any type and is used to interconnect the processor, memory, and communication interface.

[0219] The communication interface includes input / output (I / O) interfaces, physical interfaces, and logical interfaces for interconnecting components within the propulsion shaft abnormal torsional vibration suppression device, as well as interfaces for interconnecting the propulsion shaft abnormal torsional vibration suppression device with other devices (such as other computing devices or user equipment). Physical interfaces can be Ethernet interfaces, fiber optic interfaces, ATM interfaces, etc.; user equipment can be displays, keyboards, etc.

[0220] Memory can be various types of storage media, such as random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), flash memory, optical storage, hard disk, programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), etc.

[0221] The processor can be a general-purpose processor, which can call the propulsion shaft abnormal torsional vibration suppression program stored in the memory and execute the propulsion shaft abnormal torsional vibration suppression method provided in the embodiments of this application. For example, the general-purpose processor can be a central processing unit (CPU). The method executed when the propulsion shaft abnormal torsional vibration suppression program is called can refer to the various embodiments of the propulsion shaft abnormal torsional vibration suppression method of this application, and will not be repeated here.

[0222] Those skilled in the art will understand that Figure 11The hardware structure shown does not constitute a limitation of this application and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0223] Fourthly, embodiments of this application also provide a readable storage medium.

[0224] The present application has a storage medium storing a propulsion shaft abnormal torsional vibration suppression program, wherein when the propulsion shaft abnormal torsional vibration suppression program is executed by a processor, it implements the steps of the propulsion shaft abnormal torsional vibration suppression method as described above.

[0225] The method implemented when the abnormal torsional vibration suppression procedure of the propulsion shaft system is executed can be referred to in various embodiments of the abnormal torsional vibration suppression method of the propulsion shaft system of this application, and will not be repeated here.

[0226] It should be noted that the sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0227] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device to execute the methods described in the various embodiments of this application.

[0228] The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus. The terms "first," "second," and "third," etc., are used to distinguish different objects, etc., and do not indicate a sequence, nor do they limit "first," "second," and "third" to different types.

[0229] In the description of the embodiments of this application, terms such as "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a concrete manner.

[0230] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0231] In some processes described in the embodiments of this application, multiple operations or steps are included in a specific order. However, it should be understood that these operations or steps may not be executed in the order they appear in the embodiments of this application, or they may be executed in parallel. The sequence number of the operation is only used to distinguish different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed sequentially or in parallel, and these operations or steps may be combined.

[0232] The above are merely preferred embodiments of this application and do not limit the scope of this application. Any equivalent structural or procedural transformations made based on the description and drawings of this application, or direct or indirect applications in other related technical fields, are similarly included within the scope of protection of this application.

[0233] The above are merely preferred embodiments of this application and do not limit the scope of this application. Any equivalent structural or procedural transformations made based on the description and drawings of this application, or direct or indirect applications in other related technical fields, are similarly included within the scope of protection of this application.

Claims

1. A method for suppressing abnormal torsional vibration in a propulsion shaft system, characterized in that, The method for suppressing abnormal torsional vibration in the propulsion shaft system includes: Match the torsional natural frequency and torsional mode shape corresponding to the abnormal torsional vibration frequency of the propulsion shaft system; Calculate the modal mass and modal damping ratio of the abnormal torsional vibration of the matching order, and calculate the support reaction forces at the stern and fore-stern bearings. Fit the friction coefficients between the stern bearing, the fore-stern bearing and the propulsion shaft system; Based on the support reaction force, friction coefficient, and matched torsional vibration mode, calculate the friction excitation torque under the corresponding order torsional vibration mode, as well as the Taylor expansion coefficient of the friction excitation torque; Based on the matched torsional vibration natural frequency, modal mass, modal damping ratio, and Taylor expansion coefficient, a suppression device for generating electrical damping is installed on the propulsion shaft system to suppress abnormal torsional vibration.

2. The method for suppressing abnormal torsional vibration of a propulsion shaft system as described in claim 1, characterized in that: The suppression device includes a sleeve for fitting onto the propulsion shaft system, the sleeve having multiple piezoelectric ceramic plates electrically connected to it, and a load resistor connected to one of the piezoelectric ceramic plates.

3. The method for suppressing abnormal torsional vibration in a propulsion shaft system as described in claim 2, characterized in that, The method of installing a suppression device for generating electrical damping on the propulsion shaft system based on the matched torsional vibration natural frequency, modal mass, modal damping ratio, and Taylor expansion coefficient includes: Set the structural parameters of the suppression device to satisfy: In the formula, ξ j For the matched modal damping ratio, γ 1,j M represents the Taylor expansion coefficients. j For the matched modal quality, ω j For the torsional vibration natural frequency to be matched, κ is the first electromechanical coupling coefficient, and Γ is the second electromechanical coupling coefficient; Where κ and Γ satisfy: In the formula, R L For the load resistance, C p υ represents the total capacitance after all piezoelectric ceramic sheets are connected in parallel, and υ is the electromechanical third coupling coefficient. Among them, υ and C p satisfy: In the formula, d 15 G is the piezoelectric coefficient of the piezoelectric ceramic material. p n is the shear modulus of the piezoelectric ceramic. p R represents the number of piezoelectric ceramic sheets. p h is the radius of the piezoelectric ceramic sheet bonding location. p L represents the thickness of the piezoelectric ceramic sheet. p1 and L p2 To suppress the distance between the tip and tip of the device and the center of the propeller, Let be the dielectric constant of the piezoelectric ceramic sheet, and α be the central angle corresponding to the width of each piezoelectric ceramic sheet.

4. The method for suppressing abnormal torsional vibration in a propulsion shaft system as described in claim 3, characterized in that, The friction coefficients between the fitted stern bearing, fore-stern bearing, and propulsion shaft system include: According to the formula: The friction coefficient between the stern bearing and the propulsion shaft system after fitting; In the formula, μ b μ is the coefficient of friction between the stern bearing and the propulsion shaft system. b,1 Let μ be the coefficient of dynamic friction between the stern bearing and the propulsion shaft system. b,0 Let a be the static friction coefficient between the stern bearing and the propulsion shaft system. b R is a constant. b ω is the outer radius of the shaft system at the stern bearing, ω is the relative angular velocity between the bearing shell and the shaft system surface, and sign() is the sign function; According to the formula: Fit the friction coefficient between the fore-and-aft bearing and the propulsion shaft system; In the formula, μ f μ is the coefficient of friction between the forward and stern bearings and the propulsion shaft system. f,1 Let μ be the coefficient of dynamic friction between the fore-and-aft bearing and the propulsion shaft system. f,0 Let a be the static friction coefficient between the fore-and-aft bearing and the propulsion shaft system. f R is a constant. f ω is the outer radius of the shaft system at the front and rear bearings, ω is the relative angular velocity between the bearing and the shaft system surface, and sign() is the sign function.

5. The method for suppressing abnormal torsional vibration in a propulsion shaft system as described in claim 4, characterized in that, The calculation of the frictional excitation torque under the corresponding order torsional vibration mode, and the Taylor expansion coefficient of the frictional excitation torque, based on the support reaction force, friction coefficient, and matched torsional vibration mode, includes: According to the formula: Calculate the frictional excitation torque under the corresponding order mode shape; In the formula, F j This refers to the frictional excitation torque under the corresponding torsional vibration mode. and N represents the mode shape values ​​at the aft and forward stern bearings, respectively, under the corresponding torsional vibration mode shapes. b and N f R represents the support reaction force at the aft and forward stern bearings, respectively. b and R f Let Ω be the outer radius at the stern and fore-stern bearings of the shaft system, respectively, and q be the rotational speed of the shaft system. j (t) represents the torsional displacement in the coordinate system of the corresponding torsional vibration mode; According to the formula: Taylor expansion of the friction excitation torque; In the formula, γ 0,j γ 1,j γ 2,j γ 3,j The coefficients of the Taylor expansion; Where, γ 1,j Represented as:

6. The method for suppressing abnormal torsional vibration in a propulsion shaft system as described in claim 1, characterized in that, The torsional natural frequency and mode shape corresponding to the abnormal torsional vibration frequency of the matching propulsion shaft system include: Determine the abnormal torsional vibration frequency of the propulsion shaft system; A torsional vibration analysis model of the propulsion shaft system was established, and the torsional natural frequencies under multiple orders of the torsional vibration analysis model were obtained. Determine the torsional natural frequency of the order closest to the abnormal torsional vibration frequency, and determine the torsional mode shape of the corresponding order.

7. The method for suppressing abnormal torsional vibration in a propulsion shaft system as described in claim 6, characterized in that, Also includes: The torsional vibration modes of abnormal torsional vibrations are normalized according to the maximum absolute value.

8. A device for suppressing abnormal torsional vibration in a propulsion shaft system, characterized in that, The abnormal torsional vibration suppression device for the propulsion shaft system includes: The calculation module is used for: Match the torsional natural frequency and torsional mode shape corresponding to the abnormal torsional vibration frequency of the propulsion shaft system; Calculate the modal mass and modal damping ratio of the abnormal torsional vibration of the matching order, and calculate the support reaction forces at the stern and fore-stern bearings. Fit the friction coefficients between the stern bearing, the fore-stern bearing and the propulsion shaft system; Based on the support reaction force, friction coefficient, and matched torsional vibration mode, calculate the friction excitation torque under the corresponding order torsional vibration mode, as well as the Taylor expansion coefficient of the friction excitation torque; The module is configured to install a suppression device on the propulsion shaft to generate electrical damping, based on the matched torsional vibration natural frequency, modal mass, modal damping ratio, and Taylor expansion coefficient, in order to suppress abnormal torsional vibration.

9. A device for suppressing abnormal torsional vibration in a propulsion shaft system, characterized in that, The propulsion shaft abnormal torsional vibration suppression device includes a processor, a memory, and a propulsion shaft abnormal torsional vibration suppression program stored in the memory and executable by the processor, wherein when the propulsion shaft abnormal torsional vibration suppression program is executed by the processor, it implements the steps of the propulsion shaft abnormal torsional vibration suppression method as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a propulsion shaft abnormal torsional vibration suppression program, wherein when the propulsion shaft abnormal torsional vibration suppression program is executed by a processor, it implements the steps of the propulsion shaft abnormal torsional vibration suppression method as described in any one of claims 1 to 7.

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