Compressor foot pad condition monitoring method, system, and hardness composite compressor foot pad

Abstract

The compressor foot pad state monitoring method, system and hardness composite compressor foot pad comprises: calculating dynamic stiffness deviation coupling coefficient by combining real-time vibration acceleration, deformation amplitude and vibration main frequency; calculating damping dissipation phase coupling factor by combining real-time vibration amplitude, deformation amplitude and phase difference; judging working condition grade based on real-time vibration intensity, vibration main frequency and dynamic stiffness deviation coupling coefficient; if it is an out-of-limit fault working condition, judging the type of fault based on the dynamic stiffness deviation coupling coefficient and the damping dissipation phase coupling factor; calculating single-stage theoretical damage based on the rubber material strain fatigue curve, and correcting the single-stage theoretical damage; superimposing all single-stage actual damages to obtain the total fatigue damage amount, and calculating the remaining service life based on the total fatigue damage amount. The present application carries out online monitoring of working conditions, fault types and remaining life based on related parameters of vibration and deformation, and provides comprehensive monitoring basis for safe operation of equipment.

Description

Technical Field

[0001] This invention belongs to the field of compressor vibration damping technology, and more specifically, relates to a method and system for monitoring the condition of compressor foot pads and a composite hardness compressor foot pad. Background Technology

[0002] The compressor is the core power component of the air conditioning and refrigeration system. During operation, it continuously generates high-frequency micro-vibration, mid-frequency resonance and low-frequency impact vibration. The vibration is transmitted to the whole machine frame through the bottom foot pads, which can easily cause problems such as excessive noise of the unit, stress concentration in the pipeline, loose screws, fatigue cracking of the pipeline, and aging of electrical components, which seriously affect the reliability and service life of the equipment.

[0003] Most existing compressor vibration damping pads use a single-hardness rubber structure, which has significant drawbacks: hard rubber pads offer good support rigidity but poor low-frequency vibration damping and are prone to resonance; soft rubber pads provide good vibration damping but have poor high-frequency stability and are prone to collapse and deformation. A few existing improved technologies use double-layer or multi-layer composite rubber pads, optimizing vibration damping through hardness layering, but core gaps remain in current technology. First, the existing composite foot pads are only passive vibration damping structures without any monitoring functions, making it impossible to know the vibration damping status of the foot pads and the vibration changes of the whole machine in real time. Secondly, rubber foot pads are subjected to reciprocating alternating loads for a long time, which makes them prone to fatigue aging, hardening cracks, and permanent deformation. Existing technology cannot predict failure in advance, and can only passively repair after the equipment makes abnormal noises or vibrates excessively, resulting in serious maintenance delays. Third, it is impossible to distinguish the source of abnormal vibration, making it difficult to quickly determine whether the fault originates from a compressor malfunction or a failure of the foot pads to dampen vibrations, resulting in low fault diagnosis efficiency.

[0004] In summary, traditional composite foot pads only address the issue of vibration reduction layering, but fail to solve the technical challenges of condition sensing, fatigue monitoring, and lifespan prediction. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method and system for monitoring the condition of compressor foot pads, as well as a composite compressor foot pad with hardness.

[0006] The present invention adopts the following technical solution.

[0007] The first aspect of this invention provides a method for monitoring the condition of compressor foot pads, comprising: The system acquires real-time vibration intensity, vibration acceleration, deformation amplitude, vibration dominant frequency, and phase difference between vibration acceleration and deformation displacement of the compressor foot pads; and obtains the strain fatigue curve of the rubber material used in the compressor foot pads under normal operating conditions. The dynamic stiffness deviation coupling coefficient is calculated by combining real-time vibration acceleration, deformation amplitude, and vibration dominant frequency; the damping dissipation phase coupling factor is calculated by combining real-time vibration amplitude, deformation amplitude, and phase difference. The operating condition level is determined based on real-time vibration intensity, vibration dominant frequency, and dynamic stiffness deviation coupling coefficient. The operating condition level includes normal operating condition, slightly abnormal operating condition, significantly abnormal operating condition, and over-limit fault operating condition. If it is an over-limit fault operating condition, the type of fault is determined based on the dynamic stiffness deviation coupling coefficient and the damping dissipation phase coupling factor. The deformation amplitude of the compressor foot pad during operation is divided into multiple deformation amplitude intervals. Based on the strain fatigue curve of the rubber material, the single-stage theoretical damage of the compressor foot pad in each deformation amplitude interval is calculated. The single-stage theoretical damage is then corrected by combining the ambient temperature, dynamic stiffness deviation coupling coefficient and damping dissipation phase coupling factor to obtain the single-stage actual damage. The single-stage actual damage of all deformation amplitude intervals is superimposed to obtain the total fatigue damage. The remaining service life is calculated based on the total fatigue damage. The operating status of the compressor foot pads is output, including the operating condition level, fault type, and remaining service life.

[0008] Preferably, the calculation of the dynamic stiffness deviation coupling coefficient by combining real-time vibration acceleration, deformation amplitude, and dominant vibration frequency is specifically as follows: The vibration acceleration includes triaxial vibration acceleration, and the square root of the sum of the squares of the amplitudes of the triaxial vibration acceleration is the triaxial composite vibration acceleration amplitude. Divide the triaxial composite vibration acceleration amplitude by the deformation amplitude to obtain the real-time equivalent dynamic stiffness; Divide the dominant vibration frequency by the baseline dominant frequency as the base, use the set rubber material dynamic stiffness frequency influence index as the index, perform exponential calculation, multiply the exponential calculation result by the ratio of real-time equivalent dynamic stiffness to baseline dynamic stiffness, and subtract 1 from the multiplication result to obtain the dynamic stiffness deviation coupling coefficient. The baseline dominant frequency and baseline dynamic stiffness are the vibration dominant frequency and equivalent dynamic stiffness obtained under normal working conditions, respectively; the dynamic stiffness deviation coupling coefficient represents the relative deviation between the actual dynamic stiffness of the rubber after vibration dominant frequency correction and the baseline dynamic stiffness.

[0009] Preferably, the calculation of the damping dissipation phase coupling factor by combining real-time vibration amplitude, deformation amplitude, and phase difference specifically involves: The amplitude of the triaxial vibration acceleration, the amplitude of the deformation, and The product of these products is used as the numerator, where Phase difference; Will The product of the baseline single-cycle elastic strain energy and the baseline damping loss factor is used as the denominator, where the baseline single-cycle elastic strain energy and the baseline damping loss factor are the single-cycle elastic strain energy and damping loss factor obtained under normal operating conditions, respectively. The quotient obtained by dividing the numerator by the denominator is used as the damping dissipation phase coupling factor; the damping dissipation phase coupling factor is used to characterize the phase matching degree between vibration energy input and deformation energy dissipation.

[0010] Preferably, the fault level determination based on the coupling coefficient of real-time vibration intensity, dominant vibration frequency, and dynamic stiffness deviation specifically involves: The vibration intensity ratio is obtained by dividing the real-time vibration intensity by the baseline vibration intensity; the frequency offset rate is obtained by dividing the absolute value of the difference between the real-time vibration dominant frequency and the baseline dominant frequency by the baseline dominant frequency; where the baseline vibration intensity and the baseline dominant frequency are the vibration intensity and vibration dominant frequency obtained under normal working conditions, respectively. Three normal conditions are set: the vibration intensity ratio is less than the set first intensity ratio threshold, the main frequency offset rate is less than the set first offset rate threshold, and the absolute value of the dynamic stiffness deviation coupling coefficient is less than the set first dynamic stiffness deviation threshold. Two severe fault conditions are set: the vibration intensity ratio is greater than or equal to the set second intensity ratio threshold, and the main frequency deviation rate is greater than or equal to the set second deviation rate threshold; the second intensity ratio threshold is greater than the first intensity ratio threshold, and the second deviation rate threshold is greater than the first deviation rate threshold. If all three normal conditions are met, it is a normal operating condition. If it is not a normal operating condition and does not meet any of the serious fault conditions, it is a slightly abnormal operating condition. If only one serious fault condition is met, it is a significantly abnormal operating condition. If two serious fault conditions are met, it is an over-limit fault operating condition.

[0011] Preferably, the method of determining the fault type based on the dynamic stiffness deviation coupling coefficient and the damping dissipation phase coupling factor specifically includes: If the absolute value of the dynamic stiffness deviation coupling coefficient is greater than or equal to the set second dynamic stiffness deviation threshold and the damping dissipation phase coupling factor is less than the set damping dissipation phase threshold, then it is judged as a mechanical connection loosening fault. If the absolute value of the dynamic stiffness deviation coupling coefficient is less than the set second dynamic stiffness deviation threshold and the damping dissipation phase coupling factor is greater than or equal to the set damping dissipation phase threshold, then it is judged as a rubber damping performance degradation type fault. If the absolute value of the dynamic stiffness deviation coupling coefficient is greater than or equal to the set second dynamic stiffness deviation threshold and the damping dissipation phase coupling factor is greater than or equal to the set damping dissipation phase threshold, it is judged that there are both mechanical connection loosening faults and rubber damping performance degradation faults. If the absolute value of the dynamic stiffness deviation coupling coefficient is less than the set second dynamic stiffness deviation threshold and the damping dissipation phase coupling factor is less than the set damping dissipation phase threshold, then it is determined to be an internal fault of the compressor.

[0012] Preferably, the calculation of the single-stage theoretical damage of the compressor foot pads in each deformation amplitude range based on the strain fatigue curve of the rubber material specifically includes: The strain-fatigue curve of rubber materials satisfies the following: taking twice the theoretical number of fatigue cycles as the base and the fatigue strength index as the exponent, an exponential operation is performed to obtain the first exponential term; taking twice the theoretical number of fatigue cycles as the base and the fatigue ductility index as the exponent, an exponential operation is performed to obtain the second exponential term; the fatigue strength coefficient divided by the elastic modulus of the rubber material is used as the weight of the first exponential term, and the fatigue ductility coefficient is used as the weight of the second exponential term; the first exponential term and the second exponential term are weighted and summed according to their corresponding weights to equal the single-level theoretical damage in the corresponding deformation amplitude range. Based on the strain-fatigue curve of the rubber material, the theoretical fatigue cycle number of the compressor foot pad in each deformation amplitude range is obtained. The actual number of cycles in each deformation amplitude range is divided by the theoretical fatigue cycle number of the corresponding deformation amplitude range to obtain the single-level theoretical damage of the corresponding deformation amplitude range.

[0013] Preferably, the step of correcting the single-stage theoretical damage by combining ambient temperature, dynamic stiffness deviation coupling coefficient, and damping dissipation phase coupling factor to obtain the single-stage actual damage specifically involves: Divide the difference between the current ambient temperature and the set reference temperature by the set reference temperature, then multiply by the set temperature influence factor as the exponent, and use the natural base as the base to perform exponential calculation to obtain the temperature aging correction term. Add the product of the absolute value of the set dynamic stiffness weight coefficient and the dynamic stiffness deviation coupling coefficient to the product of the set damping dissipation phase weight coefficient and the damping dissipation phase coupling factor, and then add 1 to obtain the coupling damage acceleration term. Multiplying the single-level theoretical damage by the temperature aging correction term and then by the coupled damage acceleration term yields the single-level actual damage.

[0014] Preferably, the calculation of remaining service life based on total fatigue damage specifically involves: The average damage rate is obtained by dividing the total fatigue damage by the cumulative operating time of the compressor. The average load rate during compressor operation is used as the historical average load rate. The historical average load rate is divided by the rated load rate as the base, and the negative of the fatigue strength index is used as the exponent. The exponent is then used to perform an exponentiation calculation to obtain the load correction term. The remaining service life is obtained by dividing the difference between the set fatigue damage threshold and the total fatigue damage by the average damage rate and then multiplying by the load correction term.

[0015] Preferably, the strain fatigue curve of the rubber material is as follows: The strain-fatigue curve of the rubber material under normal operating conditions is used as the initial strain-fatigue curve of the rubber material. When the compressor starts running, the strain-fatigue curve of the rubber material is used as the initial strain-fatigue curve of the rubber material. After that, the fatigue strength coefficient and fatigue ductility coefficient are adaptively iterated every set period. After each set period, the current cumulative equivalent thermal aging time will be... n The product is multiplied by a set strength aging coefficient, the negative of the result is used as the exponent, and the natural base is used as the base. An exponential operation is then performed, and the result is multiplied by the fatigue strength coefficient of the initial rubber material strain-fatigue curve to obtain the iterated fatigue strength coefficient. n The set aging index; Multiply the current total fatigue damage by the set ductility degradation coefficient, take the negative of the multiplication result as the exponent, take the natural base as the base, perform exponential operation, and multiply the result of the exponential operation by the fatigue ductility coefficient of the initial rubber material strain fatigue curve to obtain the iterated fatigue ductility coefficient.

[0016] Preferably, the cumulative equivalent thermal aging time is specifically: Each cycle from the start of compressor operation to the current moment is considered as a time period. For each time period, the difference between the average ambient temperature of the corresponding time period and the set reference temperature is divided by the set reference temperature, and then multiplied by the set temperature influence factor as an exponent. The natural base is used as the base for exponential calculation. The result of the exponential calculation is multiplied by the time period duration to obtain the thermal aging time of the corresponding time period. The thermal aging times of all time periods from the start of compressor operation to the current moment are added together to obtain the cumulative equivalent thermal aging time.

[0017] A second aspect of the present invention proposes a compressor foot pad condition monitoring system based on the method described in the first aspect of the present invention, comprising a data receiving module, a vibration-deformation coupling characteristic calculation module, a fault judgment module, a life calculation module, and an output module, specifically: Data receiving module: used to acquire real-time vibration intensity, vibration acceleration, deformation amplitude, vibration dominant frequency, and phase difference between vibration acceleration and deformation displacement of compressor foot pads; and to acquire strain fatigue curves of the rubber material used in compressor foot pads under normal operating conditions; Vibration-deformation coupling characteristic calculation module: used to calculate the dynamic stiffness deviation coupling coefficient by combining real-time vibration acceleration, deformation amplitude and vibration dominant frequency; and to calculate the damping dissipation phase coupling factor by combining real-time vibration amplitude, deformation amplitude and phase difference. Fault Judgment Module: Used to determine the working condition level based on real-time vibration intensity, vibration dominant frequency and dynamic stiffness deviation coupling coefficient. The working condition level includes normal working condition, slightly abnormal working condition, significantly abnormal working condition and over-limit fault working condition. If it is an over-limit fault working condition, the fault type is determined based on the dynamic stiffness deviation coupling coefficient and damping dissipation phase coupling factor. The life calculation module is used to divide all deformation amplitude values ​​of the compressor foot pads during operation into multiple deformation amplitude ranges; calculate the single-stage theoretical damage of the compressor foot pads in each deformation amplitude range based on the strain fatigue curve of the rubber material, and correct the single-stage theoretical damage by combining the ambient temperature, dynamic stiffness deviation coupling coefficient and damping dissipation phase coupling factor to obtain the single-stage actual damage; superimpose the single-stage actual damage of all deformation amplitude ranges to obtain the total fatigue damage, and calculate the remaining service life based on the total fatigue damage; Output module: Used to output the operating status of the compressor foot pads, including the operating condition level, fault type, and remaining service life.

[0018] The third aspect of this invention proposes a hardness composite compressor foot pad, integrating the compressor foot pad status monitoring system described in the second aspect of this invention. The hardness composite compressor foot pad further includes a high-hardness rubber layer 5, a medium-hardness rubber layer 6, a low-hardness rubber layer 7, bolt holes 8, a protective enclosure 9, a piezoelectric deformation sensor 10, a triaxial vibration sensor 11, a signal transmission sensor 12, and a flexible signal cable 13. Specifically: The bolt hole 8 is used to fix the compressor to the compressor pad; The bolt hole 8 is wrapped with a layer of rubber material, which is composed of the high-hardness rubber layer 5, the medium-hardness rubber layer 6 and the low-hardness rubber layer 7 stacked and bonded from top to bottom; The Shore hardness of the high-hardness rubber layer 5 is greater than that of the medium-hardness rubber layer 6; the Shore hardness of the medium-hardness rubber layer 6 is greater than that of the low-hardness rubber layer 7. The encapsulation protective shell 9 is embedded and fixed inside the medium hardness rubber layer 6, and the piezoelectric deformation sensor 10 and the triaxial vibration sensor 11 are embedded and fixed inside the encapsulation protective shell 9. The triaxial vibration sensor 11 is used to collect the real-time vibration intensity, vibration acceleration, vibration frequency, and vibration acceleration of the compressor foot pads; the piezoelectric deformation sensor 10 is used to collect the deformation amplitude and deformation displacement. The signal transmission sensor 12 transmits the real-time vibration intensity, vibration acceleration, vibration frequency, vibration acceleration, deformation amplitude, and deformation displacement of the compressor foot pad to the compressor foot pad status monitoring system via the flexible signal cable 13.

[0019] The beneficial effects of this invention are compared with those of the prior art: 1. This invention integrates multi-source sensing parameters such as vibration intensity, acceleration, deformation, dominant frequency, and phase difference to calculate the dynamic stiffness deviation coupling coefficient and damping dissipation phase coupling factor, thereby achieving a synergistic characterization of stiffness degradation and damping deterioration of rubber foot pads. Based on this, it can accurately determine the operating condition level and identify the fault type. Furthermore, it performs fatigue calculations based on strain fatigue curves and, after temperature, stiffness, and damping coupling corrections, achieves remaining life prediction, enabling online assessment of the health status of compressor foot pads and providing a reliable basis for preventive maintenance.

[0020] 2. This invention introduces an exponential correction of the dominant vibration frequency in the dynamic stiffness calculation, which effectively eliminates the influence of frequency changes on stiffness assessment, making the dynamic stiffness deviation coupling coefficient more accurately reflect the degree of stiffness degradation of the rubber material itself.

[0021] 3. This invention utilizes the vibration acceleration amplitude, deformation amplitude, and phase difference to construct a damping dissipation phase coupling factor, which can directly quantify the phase matching relationship between vibration energy input and deformation energy dissipation, thereby improving the sensitivity of identifying changes in damping characteristics.

[0022] 4. This invention uses three indicators—vibration intensity ratio, dominant frequency offset rate, and dynamic stiffness deviation—to jointly determine the working condition level. The classification logic is clear, which facilitates engineering implementation and real-time online application.

[0023] 5. This invention classifies over-limit faults based on dynamic stiffness deviation coupling coefficient and damping dissipation phase coupling factor, which can effectively distinguish the root causes of different types of problems such as loose mechanical connections, rubber damping attenuation, and internal compressor faults.

[0024] 6. This invention calculates the theoretical damage for each deformation amplitude range step by step based on the strain fatigue curve of rubber material, which can accurately reflect the fatigue accumulation effect under different deformation levels and provide accurate basic data for the calculation of total damage.

[0025] 7. This invention introduces a joint correction of ambient temperature, dynamic stiffness deviation and damping dissipation phase factor on the basis of single-stage theoretical damage, so that the single-stage actual damage is closer to the fatigue consumption under the actual service conditions of the foot pad, thus improving the accuracy of damage assessment.

[0026] 8. This invention estimates the remaining service life by combining the average damage rate and load rate correction, taking into account the impact of actual load conditions on fatigue life.

[0027] 9. The present invention adaptively iterates and updates the fatigue strength coefficient and fatigue ductility coefficient every set period, so that the strain fatigue curve of the rubber material can be dynamically adjusted with aging and damage accumulation, and the remaining life prediction remains effective.

[0028] 10. This invention converts the ambient temperature at each time period into equivalent thermal aging time and adds them up, which can quantitatively characterize the long-term cumulative effect of temperature on the performance degradation of rubber materials.

[0029] 11. This invention modularizes data reception, coupling feature calculation, fault diagnosis, and lifespan calculation, enabling automatic completion of the entire process from sensor signal input to operating status output.

[0030] 12. The composite structure of the hardness composite compressor foot pad of the present invention makes the overall stiffness decrease gradually from top to bottom and the stress distribution uniform, effectively avoiding the problems of interlayer delamination and local stress concentration. Attached Figure Description

[0031] Figure 1 This is a three-dimensional schematic diagram of the overall structure of the compressor; Figure 2 A schematic diagram of the cross-section of the hardness composite compressor foot pad; Figure 3 This is a flowchart for monitoring the condition of compressor foot pads.

[0032] The attached figures are labeled as follows: 1-compressor; 2-rubber material; 3-compressor pad; 4-signal transmission unit; 5-high hardness rubber layer; 6-medium hardness rubber layer; 7-low hardness rubber layer; 8-bolt hole; 9-encapsulation protective shell; 10-piezoelectric deformation sensor; 11-triaxial vibration sensor; 12-signal transmission sensor; 13-flexible signal cable. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. The embodiments described in this application are merely some embodiments of this invention, and not all embodiments. Based on the spirit of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this invention.

[0034] like Figure 3 As shown, Embodiment 1 of the present invention proposes a method for monitoring the status of compressor foot pads, comprising: Real-time parameters of the compressor foot pads are collected, including vibration intensity, vibration acceleration, deformation amplitude, vibration dominant frequency, and the phase difference between vibration acceleration and deformation displacement, at a frequency of 1 kHz. The acquired parameters are then filtered and denoised. A baseline database is established, including the rubber material strain fatigue curve, baseline dynamic stiffness, baseline dominant frequency, baseline single-cycle elastic strain energy, baseline damping loss factor, and baseline vibration intensity of the compressor under normal operating conditions (i.e., standard rated power). Ambient temperature and compressor load rate are also acquired in real-time. It should be noted that the deformation amplitude is the peak deformation value during one deformation cycle, and the deformation displacement is the instantaneous deformation. The dynamic stiffness deviation coupling coefficient is calculated by combining real-time vibration acceleration, deformation amplitude, and vibration dominant frequency. The dynamic stiffness deviation coupling coefficient represents the relative deviation between the actual dynamic stiffness of the rubber after correction by the vibration dominant frequency and the baseline dynamic stiffness. The damping dissipation phase coupling factor is calculated by combining real-time vibration amplitude, deformation amplitude, and phase difference. The damping dissipation phase coupling factor is used to characterize the phase matching degree between vibration energy input and deformation energy dissipation. The operating condition level is determined based on real-time vibration intensity, vibration dominant frequency, and dynamic stiffness deviation coupling coefficient. The operating condition level includes normal operating condition, slightly abnormal operating condition, significantly abnormal operating condition, and over-limit fault operating condition. If it is an over-limit fault operating condition, the type of fault is determined based on the dynamic stiffness deviation coupling coefficient and the damping dissipation phase coupling factor. The deformation amplitude of the compressor foot pad during operation is divided into multiple deformation amplitude intervals. Based on the strain fatigue curve of the rubber material, the single-stage theoretical damage of the compressor foot pad in each deformation amplitude interval is calculated. The single-stage theoretical damage is then corrected by combining the ambient temperature, dynamic stiffness deviation coupling coefficient and damping dissipation phase coupling factor to obtain the single-stage actual damage. The single-stage actual damage of all deformation amplitude intervals is superimposed to obtain the total fatigue damage. The remaining service life is calculated based on the total fatigue damage. The operating status of the compressor foot pads is output, including the operating condition level, fault type, and remaining service life.

[0035] It should be noted that this embodiment integrates multi-source sensing parameters such as vibration intensity, acceleration, deformation, dominant frequency, and phase difference to calculate the dynamic stiffness deviation coupling coefficient and damping dissipation phase coupling factor, thereby achieving a synergistic characterization of stiffness degradation and damping deterioration of the rubber foot pads. Based on this, it can accurately determine the operating condition level and identify the fault type; and perform fatigue calculations based on strain fatigue curves, and achieve remaining life prediction after temperature, stiffness, and damping coupling corrections. This enables online assessment of the health status of the compressor foot pads, providing a reliable basis for preventive maintenance.

[0036] In this preferred embodiment, the calculation of the dynamic stiffness deviation coupling coefficient by combining real-time vibration acceleration, deformation amplitude, and vibration dominant frequency is specifically as follows: The vibration acceleration includes triaxial vibration acceleration, and the square root of the sum of the squares of the amplitudes of the triaxial vibration acceleration is the triaxial composite vibration acceleration amplitude. Divide the triaxial composite vibration acceleration amplitude by the deformation amplitude to obtain the real-time equivalent dynamic stiffness; Divide the dominant vibration frequency by the baseline dominant frequency as the base, use the set rubber material dynamic stiffness frequency influence index as the index, perform exponential calculation, multiply the exponential calculation result by the ratio of real-time equivalent dynamic stiffness to baseline dynamic stiffness, and subtract 1 from the multiplication result to obtain the dynamic stiffness deviation coupling coefficient. The baseline dominant frequency and baseline dynamic stiffness are the vibration dominant frequency and equivalent dynamic stiffness obtained under normal operating conditions, respectively.

[0037] Specifically, the dynamic stiffness deviation coupling coefficient The formula is:

[0038] in, For real-time equivalent dynamic stiffness, , For triaxial composite vibration acceleration, , , They are respectively x axis, y axis, z The vibration acceleration of the shaft; This represents the deformation amplitude. Baseline dynamic stiffness; This is the dominant vibration frequency; Baseline frequency; The frequency influence index of the dynamic stiffness of the rubber material is set, with a value of 0.2 to 0.4.

[0039] It should be noted that this embodiment introduces an exponential correction of the dominant vibration frequency in the dynamic stiffness calculation, which effectively eliminates the influence of frequency changes on stiffness assessment, making the dynamic stiffness deviation coupling coefficient more accurately reflect the degree of stiffness degradation of the rubber material itself.

[0040] In this preferred embodiment, the calculation of the damping dissipation phase coupling factor by combining the real-time vibration amplitude, deformation amplitude, and phase difference is specifically as follows: The amplitude of the triaxial vibration acceleration, the amplitude of the deformation, and The product of these products is used as the numerator, where Phase difference; Will The product of the baseline single-cycle elastic strain energy and the baseline damping loss factor is used as the denominator, where the baseline single-cycle elastic strain energy and the baseline damping loss factor are the single-cycle elastic strain energy and damping loss factor obtained under normal operating conditions, respectively. The quotient obtained by dividing the numerator by the denominator is used as the damping dissipation phase coupling factor.

[0041] Specifically, damping dissipation phase coupling factor for:

[0042] in, This represents the amplitude of the triaxial composite vibration acceleration. This represents the phase difference between vibration acceleration and deformation displacement. The baseline single-cycle elastic strain energy; This represents the baseline damping loss factor.

[0043] It should be noted that this embodiment utilizes the vibration acceleration amplitude, deformation amplitude, and phase difference to construct a damping dissipation phase coupling factor, which can directly quantify the phase matching relationship between vibration energy input and deformation energy dissipation, thereby improving the sensitivity of identifying changes in damping characteristics.

[0044] In this preferred embodiment, the fault level determination based on the coupling coefficient of real-time vibration intensity, vibration dominant frequency, and dynamic stiffness deviation specifically involves: The vibration intensity ratio is obtained by dividing the real-time vibration intensity by the baseline vibration intensity; the frequency offset rate is obtained by dividing the absolute value of the difference between the real-time vibration dominant frequency and the baseline dominant frequency by the baseline dominant frequency; where the baseline vibration intensity and the baseline dominant frequency are the vibration intensity and vibration dominant frequency obtained under normal working conditions, respectively. Three normal conditions are set: the vibration intensity ratio is less than the set first intensity ratio threshold, the main frequency offset rate is less than the set first offset rate threshold, and the absolute value of the dynamic stiffness deviation coupling coefficient is less than the set first dynamic stiffness deviation threshold. Two severe fault conditions are set: the vibration intensity ratio is greater than or equal to the set second intensity ratio threshold, and the main frequency deviation rate is greater than or equal to the set second deviation rate threshold; the second intensity ratio threshold is greater than the first intensity ratio threshold, and the second deviation rate threshold is greater than the first deviation rate threshold. If all three normal conditions are met, it is a normal operating condition. If it is not a normal operating condition and does not meet any of the serious fault conditions, it is a slightly abnormal operating condition. If only one serious fault condition is met, it is a significantly abnormal operating condition. If two serious fault conditions are met, it is an over-limit fault operating condition.

[0045] Specifically, the first intensity ratio threshold and the second intensity ratio threshold are set to 1.5 and 2.5, respectively; the first offset rate threshold and the second offset rate threshold are set to 5% and 10%, respectively; and the first dynamic stiffness deviation threshold is set to 0.1.

[0046] It should be noted that this embodiment uses three indicators—vibration intensity ratio, dominant frequency offset rate, and dynamic stiffness deviation—to jointly determine the working condition level. The classification logic is clear and facilitates engineering implementation and real-time online application.

[0047] In this preferred embodiment, the method of determining the fault type based on the dynamic stiffness deviation coupling coefficient and the damping dissipation phase coupling factor specifically involves: If the absolute value of the dynamic stiffness deviation coupling coefficient is greater than or equal to the set second dynamic stiffness deviation threshold and the damping dissipation phase coupling factor is less than the set damping dissipation phase threshold, then it is judged as a mechanical connection loosening fault. If the absolute value of the dynamic stiffness deviation coupling coefficient is less than the set second dynamic stiffness deviation threshold and the damping dissipation phase coupling factor is greater than or equal to the set damping dissipation phase threshold, then it is judged as a rubber damping performance degradation type fault. If the absolute value of the dynamic stiffness deviation coupling coefficient is greater than or equal to the set second dynamic stiffness deviation threshold and the damping dissipation phase coupling factor is greater than or equal to the set damping dissipation phase threshold, it is judged that there are both mechanical connection loosening faults and rubber damping performance degradation faults. If the absolute value of the dynamic stiffness deviation coupling coefficient is less than the set second dynamic stiffness deviation threshold and the damping dissipation phase coupling factor is less than the set damping dissipation phase threshold, then it is determined to be an internal fault of the compressor.

[0048] Specifically, the second dynamic stiffness deviation threshold is set to 0.2; the damping dissipation phase threshold is set to 0.3.

[0049] It should be noted that this embodiment classifies over-limit faults based on the dynamic stiffness deviation coupling coefficient and the damping dissipation phase coupling factor, which can effectively distinguish the root causes of different types of problems such as loose mechanical connections, rubber damping attenuation, and internal compressor faults.

[0050] In this preferred embodiment, the calculation of the single-stage theoretical damage of the compressor foot pads in each deformation amplitude range based on the strain fatigue curve of the rubber material specifically includes: The strain-fatigue curve of rubber materials satisfies the following: taking twice the theoretical number of fatigue cycles as the base and the fatigue strength index as the exponent, an exponential operation is performed to obtain the first exponential term; taking twice the theoretical number of fatigue cycles as the base and the fatigue ductility index as the exponent, an exponential operation is performed to obtain the second exponential term; the fatigue strength coefficient divided by the elastic modulus of the rubber material is used as the weight of the first exponential term, and the fatigue ductility coefficient is used as the weight of the second exponential term; the first exponential term and the second exponential term are weighted and summed according to their corresponding weights to equal the single-level theoretical damage in the corresponding deformation amplitude range. Specifically, the strain fatigue curve (or Manson-Coffin strain fatigue equation) of rubber materials is as follows:

[0051] in, For the first i The midpoint of the deformation amplitude range; This is the fatigue strength coefficient; The fatigue strength index; It is the fatigue ductility coefficient; It is the fatigue ductility index; For the first i The theoretical number of fatigue cycles for each deformation amplitude range; The elastic modulus of rubber materials; Based on the strain-fatigue curve of the rubber material, the theoretical fatigue cycle number of the compressor foot pad in each deformation amplitude range is obtained. The actual number of cycles in each deformation amplitude range is divided by the theoretical fatigue cycle number of the corresponding deformation amplitude range to obtain the single-level theoretical damage of the corresponding deformation amplitude range.

[0052] It should be noted that this embodiment calculates the theoretical damage for each deformation amplitude range step by step based on the strain fatigue curve of the rubber material, which can accurately reflect the fatigue accumulation effect under different deformation levels and provide accurate basic data for the calculation of total damage.

[0053] In this preferred embodiment, the step of correcting the single-stage theoretical damage by combining ambient temperature, dynamic stiffness deviation coupling coefficient, and damping dissipation phase coupling factor to obtain the single-stage actual damage specifically involves: Divide the difference between the current ambient temperature and the set reference temperature by the set reference temperature, then multiply by the set temperature influence factor as the exponent, and use the natural base as the base to perform exponential calculation to obtain the temperature aging correction term. Add the product of the absolute value of the set dynamic stiffness weight coefficient and the dynamic stiffness deviation coupling coefficient to the product of the set damping dissipation phase weight coefficient and the damping dissipation phase coupling factor, and then add 1 to obtain the coupling damage acceleration term. Multiplying the single-level theoretical damage by the temperature aging correction term and then by the coupled damage acceleration term yields the single-level actual damage.

[0054] Specifically, the formula for single-level actual damage for:

[0055] in, For the first i The actual number of cycles occurring within each deformation amplitude range; The theoretical damage is single-level. The set temperature influence factor has a value of 0.05 to 0.15; The current ambient temperature; This embodiment uses the set reference temperature. It is 298K; The dynamic stiffness weighting coefficient is set. For damping dissipation phase coupling factor, , Calibrated by material testing; This is a temperature aging correction item; This is a coupling damage acceleration term.

[0056] It should be noted that this embodiment introduces a joint correction of ambient temperature, dynamic stiffness deviation and damping dissipation phase factor on the basis of single-stage theoretical damage, so that the single-stage actual damage is closer to the fatigue consumption under the actual service conditions of the foot pad, thus improving the accuracy of damage assessment.

[0057] In a preferred embodiment, the calculation of remaining service life based on total fatigue damage specifically involves: The average damage rate is obtained by dividing the total fatigue damage by the cumulative operating time of the compressor.

[0058] in, The average damage rate; This represents the total fatigue damage. , This represents the total number of deformation amplitude intervals. This represents the cumulative runtime of the compressor.

[0059] The average load rate during compressor operation is used as the historical average load rate. The historical average load rate is divided by the rated load rate as the base, and the negative of the fatigue strength index is used as the exponent. The exponent is then used to perform an exponentiation calculation to obtain the load correction term. The remaining service life is obtained by dividing the difference between the set fatigue damage threshold and the total fatigue damage by the average damage rate, and then multiplying by the load correction term. Specifically:

[0060] in, Remaining useful life; The set fatigue damage threshold is set to 0.8 in this embodiment; Historical average load factor; This is the rated load rate.

[0061] When the remaining lifespan is below the preset maintenance window, a preventative replacement recommendation for the foot pads is provided.

[0062] It should be noted that this embodiment estimates the remaining service life by combining the average damage rate and load rate correction, taking into account the impact of actual load conditions on fatigue life.

[0063] In this preferred embodiment, the strain fatigue curve of the rubber material is specifically as follows: The strain-fatigue curve of the rubber material under normal operating conditions is used as the initial strain-fatigue curve of the rubber material. When the compressor starts running, the strain-fatigue curve of the rubber material is used as the initial strain-fatigue curve of the rubber material. After that, the fatigue strength coefficient and fatigue ductility coefficient are adaptively iterated every set period. After each set period, the current cumulative equivalent thermal aging time will be... n The product is multiplied by a set strength aging coefficient, the negative of the result is used as the exponent, and the natural base is used as the base. An exponential operation is then performed, and the result is multiplied by the fatigue strength coefficient of the initial rubber material strain-fatigue curve to obtain the iterated fatigue strength coefficient. n The set aging index; The formula is:

[0064] in, The fatigue strength coefficient is the initial strain fatigue curve of the rubber material. The set strength aging coefficient is taken as 2×10. -6 ; n The set aging index is 0.6 to 0.8. This is the cumulative equivalent thermal aging time.

[0065] Multiply the current total fatigue damage by the set ductility degradation coefficient, take the negative of the multiplication result as the exponent, take the natural base as the base, perform exponential operation, and multiply the exponential operation result by the fatigue ductility coefficient of the initial rubber material strain fatigue curve to obtain the iterated fatigue ductility coefficient. The formula is:

[0066] in, The fatigue ductility coefficient of the initial strain fatigue curve of the rubber material; The set ductility degradation coefficient is 0.5.

[0067] The fatigue strength coefficient and fatigue ductility coefficient are updated to the baseline database after each iteration for fatigue damage calculation in the next cycle.

[0068] It should be noted that in this embodiment, the fatigue strength coefficient and fatigue ductility coefficient are adaptively iterated and updated every set period, so that the strain fatigue curve of the rubber material can be dynamically adjusted as aging and damage accumulate, thus maintaining the continuous effectiveness of the remaining life prediction.

[0069] In this preferred embodiment, the cumulative equivalent thermal aging time is specifically: Each cycle from the start of compressor operation to the current moment is considered as a time period. For each time period, the difference between the average ambient temperature of the corresponding time period and the set reference temperature is divided by the set reference temperature, and then multiplied by the set temperature influence factor as an exponent. The natural base is used as the base for exponential calculation. The result of the exponential calculation is multiplied by the time period duration to obtain the thermal aging time of the corresponding time period. The thermal aging times of all time periods from the start of compressor operation to the current moment are added together to obtain the cumulative equivalent thermal aging time.

[0070] Specifically, the cumulative equivalent thermal aging time The formula is:

[0071] in, The duration of the j-th time period; Let J be the average ambient temperature during the j-th time period; This represents the total number of time intervals from when the compressor started running until the current moment.

[0072] It should be noted that this embodiment converts the ambient temperature at each time period into equivalent thermal aging time and adds them up, which can quantitatively characterize the long-term cumulative effect of temperature on the performance degradation of rubber materials.

[0073] Embodiment 2 of the present invention proposes a compressor foot pad condition monitoring system based on the method described in Embodiment 1 of the present invention, including a data receiving module, a vibration-deformation coupling characteristic calculation module, a fault judgment module, a life calculation module, and an output module, specifically as follows: Data receiving module: used to acquire real-time vibration intensity, vibration acceleration, deformation amplitude, vibration dominant frequency, and phase difference between vibration acceleration and deformation displacement of compressor foot pads; and to acquire strain fatigue curves of the rubber material used in compressor foot pads under normal operating conditions; The vibration-deformation coupling characteristic calculation module is used to calculate the dynamic stiffness deviation coupling coefficient by combining real-time vibration acceleration, deformation amplitude, and vibration dominant frequency. The dynamic stiffness deviation coupling coefficient represents the relative deviation between the actual dynamic stiffness of the rubber after correction by the vibration dominant frequency and the baseline dynamic stiffness. It also calculates the damping dissipation phase coupling factor by combining real-time vibration amplitude, deformation amplitude, and phase difference. The damping dissipation phase coupling factor is used to characterize the phase matching degree between vibration energy input and deformation energy dissipation. Fault Judgment Module: Used to determine the working condition level based on real-time vibration intensity, vibration dominant frequency and dynamic stiffness deviation coupling coefficient. The working condition level includes normal working condition, slightly abnormal working condition, significantly abnormal working condition and over-limit fault working condition. If it is an over-limit fault working condition, the fault type is determined based on the dynamic stiffness deviation coupling coefficient and damping dissipation phase coupling factor. The life calculation module is used to divide all deformation amplitude values ​​of the compressor foot pads during operation into multiple deformation amplitude ranges; calculate the single-stage theoretical damage of the compressor foot pads in each deformation amplitude range based on the strain fatigue curve of the rubber material, and correct the single-stage theoretical damage by combining the ambient temperature, dynamic stiffness deviation coupling coefficient and damping dissipation phase coupling factor to obtain the single-stage actual damage; superimpose the single-stage actual damage of all deformation amplitude ranges to obtain the total fatigue damage, and calculate the remaining service life based on the total fatigue damage; Output module: Used to output the operating status of the compressor foot pads, including the operating condition level, fault type, and remaining service life.

[0074] It should be noted that this embodiment modularizes data reception, coupling feature calculation, fault diagnosis, and lifetime calculation, and can automatically complete the entire process from sensor signal input to operating status output.

[0075] Embodiment 3 of the present invention proposes a hardness composite compressor foot pad, integrating the compressor foot pad status monitoring system described in Embodiment 2 of the present invention. The hardness composite compressor foot pad further includes a high-hardness rubber layer 5, a medium-hardness rubber layer 6, a low-hardness rubber layer 7, bolt holes 8, a protective enclosure 9, a piezoelectric deformation sensor 10, a triaxial vibration sensor 11, a signal transmission sensor 12, and a flexible signal cable 13. Specifically: like Figure 1 As shown, the bolt hole 8 is used to fix the compressor 1 to the compressor pad 3; The bolt hole 8 is covered with a layer of rubber material, such as Figure 2 As shown, the rubber material is composed of the high-hardness rubber layer 5, the medium-hardness rubber layer 6 and the low-hardness rubber layer 7, which are stacked and bonded together from top to bottom; The Shore hardness of the high-hardness rubber layer 5 is greater than that of the medium-hardness rubber layer 6; the Shore hardness of the medium-hardness rubber layer 6 is greater than that of the low-hardness rubber layer 7. The encapsulation protective shell 9 is embedded and fixed inside the medium hardness rubber layer 6, and the piezoelectric deformation sensor 10 and the triaxial vibration sensor 11 are embedded and fixed inside the encapsulation protective shell 9. The protective shell 9 is made of flexible insulating silicone material with a thickness of 2-4mm. It is vulcanized and fixed together with the medium-hardness rubber layer. It can elastically deform synchronously with the rubber layer and has waterproof, oil-proof and compression-resistant protective properties.

[0076] The triaxial vibration sensor 11 is used to collect the real-time vibration intensity, vibration acceleration, vibration frequency, and vibration acceleration of the compressor foot pads; the piezoelectric deformation sensor 10 is used to collect the deformation amplitude and deformation displacement. The signal transmission sensor 12 transmits the real-time vibration intensity, vibration acceleration, vibration frequency, vibration acceleration, deformation amplitude, and deformation displacement of the compressor foot pad to the compressor foot pad status monitoring system through the flexible signal cable 13, thereby achieving stable wired data transmission in a closed environment.

[0077] Specifically, a high-hardness rubber layer, a medium-hardness rubber layer, and a low-hardness rubber layer are integrally vulcanized. The high-hardness rubber layer has a Shore hardness of 75–85 HA and is used to ensure support rigidity and suppress high-frequency micro-vibrations of the machine body. The medium-hardness rubber layer has a Shore hardness of 55–65 HA and serves as an intermediate transition buffer layer to attenuate mid-frequency resonance energy. The low-hardness rubber layer has a Shore hardness of 35–45 HA and is used to absorb low-frequency, large-amplitude vibrations caused by equipment start-up, shutdown, and load fluctuations. The thickness ratio of the high-hardness, medium-hardness, and low-hardness rubber layers is 2:3:2.

[0078] It should be noted that the composite structure of the hardness composite compressor foot pads makes the overall stiffness decrease gradually from top to bottom and the stress distribution uniform, effectively avoiding the problems of interlayer delamination and local stress concentration.

[0079] This disclosure can be a system, method, and / or computer program product. A computer program product may include a computer-readable storage medium having computer-readable program instructions loaded thereon for causing a processor to implement various aspects of this disclosure.

[0080] Computer-readable storage media can be tangible devices capable of holding and storing instructions for use by an instruction execution device. Computer-readable storage media can be, for example—but not limited to—electrical storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of computer-readable storage media include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory sticks, floppy disks, mechanical encoding devices, such as punch cards or recessed protrusions storing instructions thereon, and any suitable combination of the foregoing. The computer-readable storage media used herein are not to be construed as transient signals themselves, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., light pulses through fiber optic cables), or electrical signals transmitted through wires.

[0081] The computer-readable program instructions described herein can be downloaded from computer-readable storage media to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to the computer-readable storage media in the respective computing / processing device.

[0082] Computer program instructions used to perform the operations of this disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, status setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The computer-readable program instructions may execute entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), is personalized by utilizing the status information of the computer-readable program instructions to implement various aspects of this disclosure.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A method for monitoring the condition of compressor foot pads, characterized in that, include: Obtain the real-time vibration intensity, vibration acceleration, deformation amplitude, vibration dominant frequency, and phase difference between vibration acceleration and deformation displacement of the compressor foot pads; And obtain the strain fatigue curve of the rubber material used in the compressor foot pads under normal operating conditions; The dynamic stiffness deviation coupling coefficient is calculated by combining real-time vibration acceleration, deformation amplitude, and vibration dominant frequency; the damping dissipation phase coupling factor is calculated by combining real-time vibration amplitude, deformation amplitude, and phase difference. The working condition level is determined based on the real-time vibration intensity, vibration dominant frequency and dynamic stiffness deviation coupling coefficient. The working condition level includes normal working condition, slightly abnormal working condition, significantly abnormal working condition and over-limit fault working condition. If it is an over-limit fault condition, the type of fault is determined based on the dynamic stiffness deviation coupling coefficient and the damping dissipation phase coupling factor. The deformation amplitude values ​​of the compressor foot pads during operation are divided into multiple deformation amplitude ranges; The single-stage theoretical damage of the compressor foot pads in each deformation amplitude range is calculated based on the strain fatigue curve of rubber material. The single-stage theoretical damage is then corrected by combining ambient temperature, dynamic stiffness deviation coupling coefficient and damping dissipation phase coupling factor to obtain the single-stage actual damage. The total fatigue damage is obtained by superimposing the single-level actual damage in all deformation amplitude ranges, and the remaining service life is calculated based on the total fatigue damage. The operating status of the compressor foot pads is output, including the operating condition level, fault type, and remaining service life.

2. The compressor foot pad status monitoring method according to claim 1, characterized in that: The dynamic stiffness deviation coupling coefficient is calculated by combining real-time vibration acceleration, deformation amplitude, and vibration dominant frequency, specifically as follows: The vibration acceleration includes triaxial vibration acceleration, and the square root of the sum of the squares of the amplitudes of the triaxial vibration acceleration is the triaxial composite vibration acceleration amplitude. Divide the triaxial composite vibration acceleration amplitude by the deformation amplitude to obtain the real-time equivalent dynamic stiffness; Divide the dominant vibration frequency by the baseline dominant frequency as the base, use the set rubber material dynamic stiffness frequency influence index as the index, perform exponential calculation, multiply the exponential calculation result by the ratio of real-time equivalent dynamic stiffness to baseline dynamic stiffness, and subtract 1 from the multiplication result to obtain the dynamic stiffness deviation coupling coefficient. The baseline dominant frequency and baseline dynamic stiffness are the vibration dominant frequency and equivalent dynamic stiffness obtained under normal working conditions, respectively; the dynamic stiffness deviation coupling coefficient represents the relative deviation between the actual dynamic stiffness of the rubber after vibration dominant frequency correction and the baseline dynamic stiffness.

3. The compressor foot pad status monitoring method according to claim 2, characterized in that: The damping dissipation phase coupling factor is calculated by combining real-time vibration amplitude, deformation amplitude, and phase difference, specifically as follows: The amplitude of the triaxial vibration acceleration, the amplitude of the deformation, and The product of these products is used as the numerator, where Phase difference; Will The product of the baseline single-cycle elastic strain energy and the baseline damping loss factor is used as the denominator, where the baseline single-cycle elastic strain energy and the baseline damping loss factor are the single-cycle elastic strain energy and damping loss factor obtained under normal operating conditions, respectively. The quotient obtained by dividing the numerator by the denominator is used as the damping dissipation phase coupling factor; the damping dissipation phase coupling factor is used to characterize the phase matching degree between vibration energy input and deformation energy dissipation.

4. The compressor foot pad status monitoring method according to claim 1, characterized in that: The fault level determination based on real-time vibration intensity, dominant vibration frequency, and dynamic stiffness deviation coupling coefficient is as follows: The vibration intensity ratio is obtained by dividing the real-time vibration intensity by the baseline vibration intensity; the frequency offset rate is obtained by dividing the absolute value of the difference between the real-time vibration dominant frequency and the baseline dominant frequency by the baseline dominant frequency; where the baseline vibration intensity and the baseline dominant frequency are the vibration intensity and vibration dominant frequency obtained under normal working conditions, respectively. Three normal conditions are set: the vibration intensity ratio is less than the set first intensity ratio threshold, the main frequency offset rate is less than the set first offset rate threshold, and the absolute value of the dynamic stiffness deviation coupling coefficient is less than the set first dynamic stiffness deviation threshold. Two severe fault conditions are set: the vibration intensity ratio is greater than or equal to the set second intensity ratio threshold, and the main frequency deviation rate is greater than or equal to the set second deviation rate threshold; the second intensity ratio threshold is greater than the first intensity ratio threshold, and the second deviation rate threshold is greater than the first deviation rate threshold. If all three normal conditions are met, it is a normal operating condition. If it is not a normal operating condition and does not meet any of the serious fault conditions, it is a slightly abnormal operating condition. If only one serious fault condition is met, it is a significantly abnormal operating condition. If two serious fault conditions are met, it is an over-limit fault operating condition.

5. The compressor foot pad status monitoring method according to claim 4, characterized in that: The method for determining the type of fault based on the dynamic stiffness deviation coupling coefficient and the damping dissipation phase coupling factor is as follows: If the absolute value of the dynamic stiffness deviation coupling coefficient is greater than or equal to the set second dynamic stiffness deviation threshold and the damping dissipation phase coupling factor is less than the set damping dissipation phase threshold, then it is judged as a mechanical connection loosening fault. If the absolute value of the dynamic stiffness deviation coupling coefficient is less than the set second dynamic stiffness deviation threshold and the damping dissipation phase coupling factor is greater than or equal to the set damping dissipation phase threshold, then it is judged as a rubber damping performance degradation type fault. If the absolute value of the dynamic stiffness deviation coupling coefficient is greater than or equal to the set second dynamic stiffness deviation threshold and the damping dissipation phase coupling factor is greater than or equal to the set damping dissipation phase threshold, it is judged that there are both mechanical connection loosening faults and rubber damping performance degradation faults. If the absolute value of the dynamic stiffness deviation coupling coefficient is less than the set second dynamic stiffness deviation threshold and the damping dissipation phase coupling factor is less than the set damping dissipation phase threshold, then it is determined to be an internal fault of the compressor.

6. The compressor foot pad status monitoring method according to claim 1, characterized in that: The calculation of the single-stage theoretical damage of the compressor foot pads in each deformation amplitude range based on the strain fatigue curve of rubber material is as follows: The strain-fatigue curve of rubber materials satisfies the following: taking twice the theoretical number of fatigue cycles as the base and the fatigue strength index as the exponent, an exponential operation is performed to obtain the first exponential term; taking twice the theoretical number of fatigue cycles as the base and the fatigue ductility index as the exponent, an exponential operation is performed to obtain the second exponential term; the fatigue strength coefficient divided by the elastic modulus of the rubber material is used as the weight of the first exponential term, and the fatigue ductility coefficient is used as the weight of the second exponential term; the first exponential term and the second exponential term are weighted and summed according to their corresponding weights to equal the single-level theoretical damage in the corresponding deformation amplitude range; Based on the strain-fatigue curve of the rubber material, the theoretical fatigue cycle number of the compressor foot pad in each deformation amplitude range is obtained. The actual number of cycles in each deformation amplitude range is divided by the theoretical fatigue cycle number of the corresponding deformation amplitude range to obtain the single-level theoretical damage of the corresponding deformation amplitude range.

7. The compressor foot pad status monitoring method according to claim 6, characterized in that: The single-stage theoretical damage is corrected by combining ambient temperature, dynamic stiffness deviation coupling coefficient, and damping dissipation phase coupling factor to obtain the single-stage actual damage, specifically as follows: Divide the difference between the current ambient temperature and the set reference temperature by the set reference temperature, then multiply by the set temperature influence factor as the exponent, and use the natural base as the base to perform exponential calculation to obtain the temperature aging correction term. Add the product of the absolute value of the set dynamic stiffness weight coefficient and the dynamic stiffness deviation coupling coefficient to the product of the set damping dissipation phase weight coefficient and the damping dissipation phase coupling factor, and then add 1 to obtain the coupling damage acceleration term. Multiplying the single-level theoretical damage by the temperature aging correction term and then by the coupled damage acceleration term yields the single-level actual damage.

8. The compressor foot pad status monitoring method according to claim 1, characterized in that: The calculation of remaining service life based on total fatigue damage is as follows: The average damage rate is obtained by dividing the total fatigue damage by the cumulative operating time of the compressor. The average load rate during compressor operation is used as the historical average load rate. The historical average load rate is divided by the rated load rate as the base, and the negative of the fatigue strength index is used as the exponent. The exponent is then used to perform an exponentiation calculation to obtain the load correction term. The remaining service life is obtained by dividing the difference between the set fatigue damage threshold and the total fatigue damage by the average damage rate and then multiplying by the load correction term.

9. The compressor foot pad status monitoring method according to claim 1, characterized in that: The strain fatigue curve of the rubber material is as follows: The rubber material strain fatigue curve under normal operating conditions is used as the initial rubber material strain fatigue curve. When the compressor starts running, the rubber material strain fatigue curve is used as the initial rubber material strain fatigue curve. After that, the fatigue strength coefficient and fatigue ductility coefficient are adaptively iterated every set period. After each set period, the current cumulative equivalent thermal aging time will be... n The product is multiplied by a set strength aging coefficient, the negative of the result is used as the exponent, and the natural base is used as the base. An exponential operation is then performed, and the result is multiplied by the fatigue strength coefficient of the initial rubber material strain-fatigue curve to obtain the iterated fatigue strength coefficient. n The set aging index; Multiply the current total fatigue damage by the set ductility degradation coefficient, take the negative of the multiplication result as the exponent, take the natural base as the base, perform exponential operation, and multiply the result of the exponential operation by the fatigue ductility coefficient of the initial rubber material strain fatigue curve to obtain the iterated fatigue ductility coefficient.

10. The compressor foot pad status monitoring method according to claim 9, characterized in that: The cumulative equivalent thermal aging time is specifically as follows: Each cycle from the start of compressor operation to the current moment is considered as a time period. For each time period, the difference between the average ambient temperature of the corresponding time period and the set reference temperature is divided by the set reference temperature, and then multiplied by the set temperature influence factor as an exponent. The natural base is used as the base for exponential calculation. The result of the exponential calculation is multiplied by the time period duration to obtain the thermal aging time of the corresponding time period. The thermal aging times of all time periods from the start of compressor operation to the current moment are added together to obtain the cumulative equivalent thermal aging time.

11. A compressor foot pad condition monitoring system based on the method of any one of claims 1-10, comprising a data receiving module, a vibration-deformation coupling characteristic calculation module, a fault judgment module, a life calculation module, and an output module, characterized in that: Data receiving module: used to acquire real-time vibration intensity, vibration acceleration, deformation amplitude, vibration dominant frequency, and phase difference between vibration acceleration and deformation displacement of the compressor foot pads; and to acquire the strain fatigue curve of the rubber material used in the compressor foot pads under normal operating conditions; Vibration-deformation coupling characteristic calculation module: used to calculate the dynamic stiffness deviation coupling coefficient by combining real-time vibration acceleration, deformation amplitude and vibration dominant frequency; and to calculate the damping dissipation phase coupling factor by combining real-time vibration amplitude, deformation amplitude and phase difference. Fault diagnosis module: used to determine the working condition level based on real-time vibration intensity, vibration main frequency and dynamic stiffness deviation coupling coefficient. The working condition level includes normal working condition, slightly abnormal working condition, significantly abnormal working condition and over-limit fault working condition. If it is an over-limit fault condition, the type of fault is determined based on the dynamic stiffness deviation coupling coefficient and the damping dissipation phase coupling factor. Life calculation module: used to divide all deformation amplitude values ​​of the compressor foot pads during operation into multiple deformation amplitude ranges; The single-stage theoretical damage of the compressor foot pads in each deformation amplitude range is calculated based on the strain fatigue curve of rubber material. The single-stage theoretical damage is then corrected by combining ambient temperature, dynamic stiffness deviation coupling coefficient and damping dissipation phase coupling factor to obtain the single-stage actual damage. The total fatigue damage is obtained by superimposing the single-level actual damage in all deformation amplitude ranges, and the remaining service life is calculated based on the total fatigue damage. Output module: Used to output the operating status of the compressor foot pads, including the operating condition level, fault type, and remaining service life.

12. A hardness composite compressor foot pad, integrating the compressor foot pad status monitoring system of claim 11, and further comprising a high-hardness rubber layer (5), a medium-hardness rubber layer (6), a low-hardness rubber layer (7), bolt holes (8), a protective enclosure (9), a piezoelectric deformation sensor (10); a triaxial vibration sensor (11); a signal transmission sensor (12); and a flexible signal cable (13), characterized in that: The bolt holes (8) are used to fix the compressor to the compressor pad; The bolt hole (8) is wrapped with a layer of rubber material, which is composed of the high hardness rubber layer (5), the medium hardness rubber layer (6) and the low hardness rubber layer (7) stacked and bonded from top to bottom; The Shore hardness of the high-hardness rubber layer (5) is greater than that of the medium-hardness rubber layer (6); the Shore hardness of the medium-hardness rubber layer (6) is greater than that of the low-hardness rubber layer (7). The encapsulation protective shell (9) is embedded and fixed inside the medium hardness rubber layer (6), and the piezoelectric deformation sensor (10) and the triaxial vibration sensor (11) are embedded and fixed inside the encapsulation protective shell (9). The triaxial vibration sensor (11) is used to collect the real-time vibration intensity, vibration acceleration, vibration frequency and vibration acceleration of the compressor foot pads; the piezoelectric deformation sensor (10) is used to collect the deformation amplitude and deformation displacement; The signal transmission sensor (12) transmits the real-time vibration intensity, vibration acceleration, vibration frequency, vibration acceleration, deformation amplitude and deformation displacement of the compressor foot pad to the compressor foot pad status monitoring system through the flexible signal cable (13).

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