A method for full lifecycle quality management of automotive rubber sealing strips

Abstract

This invention relates to the field of whole life cycle quality management technology, and discloses a method for whole life cycle quality management of automotive rubber sealing strips. The method includes: obtaining geometric parameters such as the effective gas volume of the bubble tube of the automotive rubber sealing strip; collecting process parameters from the manufacturing stage to establish an initial mechanical reaction force model; extracting the normal compression path and tangential relative displacement during the service stage in segments; deriving the peak gas pressure increment to generate an aerodynamic load factor and calculating the actual normal load; calculating the tangential energy dissipation of the sealing interface based on the tangential relative displacement; establishing the internal degradation state using the aerodynamic load factor and tangential energy dissipation as input conditions, updating the initial mechanical reaction force model, and generating compression stress relaxation parameters; calculating the minimum effective compression amount based on the updated reaction force model, and finally outputting the maximum effective compression deformation margin. This invention comprehensively connects manufacturing and actual service conditions, achieving precise control of deformation margin.

Description

Technical Field

[0001] This invention relates to the field of whole life cycle quality management technology, and more specifically, to a whole life cycle quality management method for automotive rubber sealing strips. Background Technology

[0002] Currently, conventional methods for assessing and controlling the degradation of seals are typically limited to simple mechanical compression testing systems. A common approach is to directly equate the mechanical reaction force obtained from uniaxial compression set tests or basic stress relaxation parameter tests to the total external stress the seal experiences during actual service. However, in real-world vehicle dynamic service scenarios, the stress patterns of rubber seals are far more complex than pure mechanical compression. On one hand, when the seal's bubble tube is compressed, the internal air is squeezed and expelled through the vent, inevitably generating significant airflow damping. Simultaneously, when the door and body seals are closed on both sides, a trapped air cavity is easily formed, causing a dramatic increase in air pressure at the moment of closing. This load amplification effect caused by aerodynamic damping is completely ignored in conventional methods, leading to a systematic underestimation or overestimation of the actual normal contact force in existing control systems.

[0003] On the other hand, in the operation of complex door systems (such as frameless doors), driving vibrations and dynamic displacement differences inevitably induce high-frequency stick-slip friction at the sealing contact interface. Conventional control methods often ignore tangential relative displacement and tangential energy dissipation caused by friction, still adhering to a single static material index to map the overall functional degradation. This oversimplification of actual stress leads to a serious distortion in the extrapolation of aging and fatigue decay, ultimately causing a directional deviation in the maximum effective compressive deformation margin. This not only easily causes early sealing failure in the later stages of vehicle service, but may also lead to redundant parameter designs in the early stages of development, failing to meet the stringent engineering requirements of refined management throughout the entire life cycle. Summary of the Invention

[0004] This invention provides a method for full life-cycle quality management of automotive rubber sealing strips, which solves the technical problems mentioned in the background art.

[0005] This invention provides a method for quality management throughout the entire lifecycle of automotive rubber sealing strips, including:

[0006] Obtain the effective gas volume of the bubble tube, the size of the vent hole, and the effective pressure-bearing area of ​​the automotive rubber sealing strip, and generate geometric parameters;

[0007] Collect process parameters during the manufacturing stage, and establish an initial mechanical reaction force model based on the process parameters;

[0008] Extract the normal compression path and tangential relative displacement during the service phase in segments;

[0009] The peak pressure increment is calculated based on the geometric parameters and the normal compression path to generate the aerodynamic load factor, and the actual normal load is calculated based on the aerodynamic load factor and the initial mechanical reaction force model.

[0010] The tangential energy dissipation of the automotive rubber sealing strip is calculated by combining the actual normal load and the tangential relative displacement.

[0011] Using the aerodynamic loading coefficient and the tangential energy dissipation as input conditions, an internal degradation state is established, and the initial mechanical reaction force model is updated based on the internal degradation state to generate an updated reaction force model, as well as compressive stress relaxation parameters.

[0012] Based on the updated reaction force model and the compression stress relaxation parameters, the minimum effective compression amount that satisfies the minimum contact pressure is calculated, and the maximum effective compression deformation margin of the automotive rubber sealing strip is output according to the minimum effective compression amount.

[0013] The beneficial effects of this invention include: This invention overcomes the shortcomings of traditional evaluations that rely solely on a single mechanical compression force while neglecting the aerodynamic load amplification effect and dynamic stick-slip friction work. By integrating manufacturing process parameters to establish an initial mechanical reaction force model, and combining the normal compression path and tangential relative displacement during the service stage, the peak air pressure increment and tangential energy consumption are accurately deduced. Furthermore, the aerodynamic load factor, together with the tangential energy consumption, is used as a driving factor to continuously evolve the internal degradation state to update the reaction force model. Ultimately, this achieves accurate quantitative output of the maximum effective compression deformation margin of the weakest segment of the entire circumference, effectively avoiding early functional degradation and design redundancy during the service life of automotive seals. Attached Figure Description

[0014] Figure 1 This is a flowchart of a method for full life-cycle quality management of automotive rubber sealing strips according to the present invention;

[0015] Figure 2 This is a schematic diagram illustrating the influence of aerodynamic loading and tangential energy dissipation on the compression margin of the present invention. Detailed Implementation

[0016] The subject matter described herein will now be discussed with reference to exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and implement the subject matter described herein, and changes may be made to the function and arrangement of the elements discussed without departing from the scope of this specification. Various processes or components may be omitted, substituted, or added as needed in the examples. Furthermore, features described in some examples may be combined in other examples.

[0017] like Figure 1As shown, a method for quality management throughout the entire lifecycle of automotive rubber sealing strips includes:

[0018] Obtain the effective gas volume of the bubble tube, the size of the vent hole, and the effective pressure-bearing area of ​​the automotive rubber sealing strip, and generate geometric parameters;

[0019] Collect process parameters during the manufacturing stage, and establish an initial mechanical reaction force model based on the process parameters;

[0020] Extract the normal compression path and tangential relative displacement during the service phase in segments;

[0021] The peak pressure increment is calculated based on the geometric parameters and the normal compression path to generate the aerodynamic load factor, and the actual normal load is calculated based on the aerodynamic load factor and the initial mechanical reaction force model.

[0022] The tangential energy dissipation of the automotive rubber sealing strip is calculated by combining the actual normal load and the tangential relative displacement.

[0023] Using the aerodynamic loading coefficient and the tangential energy dissipation as input conditions, an internal degradation state is established, and the initial mechanical reaction force model is updated based on the internal degradation state to generate an updated reaction force model, as well as compressive stress relaxation parameters.

[0024] Based on the updated reaction force model and the compression stress relaxation parameters, the minimum effective compression amount that satisfies the minimum contact pressure is calculated, and the maximum effective compression deformation margin of the automotive rubber sealing strip is output according to the minimum effective compression amount.

[0025] Preferably, the effective gas volume, vent size, and effective pressure-bearing area of ​​the automotive rubber sealing strip's bubble tube are obtained to generate geometric parameters, including:

[0026] Obtain the segment-level participation length, the cavity area of ​​the free cross section of the bubble tube, the equivalent width of the double seal, and the vent size including the vent radius, vent spacing, and equivalent wall thickness of the channel;

[0027] The effective gas volume of the bubble tube, the effective pressure-bearing area, the number of vents, the equivalent flow resistance, and the pressure relief time constant are calculated using the following formulas to form the geometric parameters:

[0028]

[0029]

[0030]

[0031]

[0032]

[0033] In the formula, This indicates the effective gas volume of the bubble tube. This represents the cavity area of ​​the free cross-section of the bubble tube. Indicates the segment-level participation length. This indicates the effective pressure-bearing area. This indicates the equivalent width between the two seals. This indicates the number of vent holes. Indicates the vent spacing. This represents the equivalent flow resistance. Represents the flow absorption constant. Indicates aerodynamic viscosity, This indicates the equivalent wall thickness of the channel. This indicates the radius of the vent hole. This represents the pressure relief time constant. This indicates the ambient reference pressure.

[0034] The segment-level engagement length is the actual length of the sealing strip involved in operation during a single door closing or pressure event. It can be obtained through computer-aided design path measurement, physical length segment measurement, or recording by a production line length encoder.

[0035] The free cross-sectional cavity area of ​​the bubble tube is the cross-sectional area of ​​the hollow portion inside the bubble tube when it is not compressed. It can be obtained through cross-sectional slice imaging measurement, extraction from computer-aided design drawings, or laser scanning cross-sectional analysis.

[0036] The equivalent width between the two seals is the average distance between the main seal and the secondary seal of the sealing strip, projected along the normal direction. It can be obtained by measuring the normal distance between the two contact lines in a computer-aided design model or by averaging multiple measurements at the actual cross-section.

[0037] The vent radius is the radius of the small hole on the sealing strip bubble tube used for pressure relief. It can be obtained by measurement using an optical microscope, a laser diameter gauge, or by annotation on computer-aided design drawings.

[0038] The vent spacing is the distance between the centers of two adjacent vents on the sealing strip. It can be obtained through photographing the actual surface, measuring with a laser rangefinder, or recording in production process documents.

[0039] The equivalent wall thickness of a vent is the equivalent thickness of the vent channel, i.e., the average thickness of the vent wall. It can be obtained through cross-sectional slicing measurement, dimensional calculation from computer-aided design drawings, or measurement with an ultrasonic thickness gauge.

[0040] The flow absorption constant is a correction constant used to absorb non-ideal factors in the airflow within the vent. It is calibrated through bench tests of the vent system, and is preferably between 1 and 5. It is adjusted according to the deviation between the measured aerodynamic load and the theoretical calculation to ensure that the calculated air pressure results are consistent with the actual results.

[0041] Aerodynamic viscosity is the viscosity coefficient of air at a specific temperature. It can be obtained by interpolating using the Sutherland formula, looking up a table, or directly measuring with a viscometer after acquiring real-time temperature data using a temperature sensor.

[0042] The environmental reference pressure is the standard atmospheric pressure of the environment in which the sealing strip operates. It can be obtained through real-time data acquisition by a pressure sensor, meteorological data query, or standard atmospheric pressure measurement.

[0043] The effective gas volume of the bubble tube is the effective volume of air that can be contained inside the sealed bubble tube.

[0044] The effective pressure-bearing area is the equivalent area where the air pressure increment acts on the sealing strip and generates a normal load.

[0045] The number of vent holes is the total number of vent holes contained within a specific length of the sealing strip.

[0046] Equivalent flow resistance is the degree to which an orifice effectively impedes airflow.

[0047] The pressure relief time constant is the time scale by which air inside the sealing strip bubble tube is depressurized through the vent hole, and it characterizes the pressure relief efficiency.

[0048] In detail, the equivalent flow resistance is a quantitative formula that uniformly corrects for non-ideal flow factors such as inlet loss, local turbulence, and inter-hole interference by using the flow absorption constant. This is then combined with aerodynamic viscosity, equivalent channel wall thickness, and the number and radius of vents to construct the quantitative formula. Thus, for the long-length extrusion characteristics and bubble tube venting structure of automotive rubber seals, the complex porous flow problem is simplified into equivalent parameters that can be calculated in engineering.

[0049] In detail, the pressure relief time constant converts the aerodynamic characteristics of the sealing strip into a quantifiable parameter by establishing a correlation between the effective gas volume of the bubble tube, the equivalent flow resistance, and the ambient reference pressure. This parameter reflects the pressure relief efficiency of the vent; the smaller the pressure relief time constant, the faster the pressure relief speed and the less pressure accumulation inside the bubble tube; conversely, the larger the time constant, the more significant the pressure accumulation.

[0050] In detail, the effective pressure-bearing area is the product of the equivalent width between the double seals and the segment-level participation length, because the core area of ​​the pneumatic load is the trapped air cavity between the main and secondary seals. This solves the problem of ambiguous action boundaries during pneumatic load conversion.

[0051] In detail, the calibration method for the flow absorption constant adopts a door system bench test. The specific steps are as follows: On the whole vehicle or door system bench, the door closing test is repeated at three different closing speeds, and the total closing force curve is collected; the pure mechanical closing force is calculated through the mechanical reaction force model, and the peak value of the difference between the two within the contact window is the aerodynamic load contribution; the aerodynamic load at each stage is summed and compared with the measured aerodynamic load contribution, and the flow absorption constant is adjusted using the bisection method until the deviation between the calculated value and the measured value is less than 5%. The value at this point is the calibrated flow absorption constant.

[0052] In detail, the measurement method for the equivalent wall thickness of the duct is to use cross-sectional slices combined with optical microscopy. The specific steps are as follows: cut 5 mm thick cross-sectional samples at the beginning, middle and end of the length of the sealing strip segment. After smoothing with metallographic sandpaper, place the sample under an optical microscope and magnify it 50 to 100 times. Select 8 measurement points evenly on the circumference of the duct, record the wall thickness at each point, and take the average. This average is the equivalent wall thickness of the duct. The measurement accuracy must be controlled within ±0.01 mm.

[0053] In detail, the equivalent width between the two seals is obtained by measuring using a computer-aided design model. The specific steps are as follows: extract the contact lines between the main seal and the secondary seal in the 3D design software, select 10 measurement sections evenly along the length of the sealing strip segment, measure the normal distance between the two contact lines in each section, remove the maximum and minimum values ​​and take the average, which is the equivalent width between the two seals. During the measurement, it is necessary to ensure that the coordinate system is consistent with the circumference path of the sealing strip.

[0054] In detail, the temperature correction method for aerodynamic viscosity uses the Sutherland formula interpolation. The specific steps are as follows: The real-time temperature of the sealing strip's service environment is collected using a temperature sensor, and the temperature value is substituted into the Sutherland formula. The reference temperature is 293.15 Kelvin (20 degrees Celsius), the reference viscosity is 1.81 × 10⁻⁵ Pascals per second, and the Sutherland constant is 110.4 Kelvin. This method is applicable to the commonly used automotive service temperature range of -40 degrees Celsius to 80 degrees Celsius, and the temperature-corrected aerodynamic viscosity error is less than 3%.

[0055] Preferably, the process parameters during the manufacturing stage are collected, and an initial mechanical reaction force model is established based on the process parameters, including:

[0056] The mixing stage temperature, torque integral energy, extrusion die temperature, extrusion line speed, extruder head pressure, vulcanization zone temperature, and vulcanization residence time are obtained as the process parameters.

[0057] Establish the mapping relationship between the process parameters and the linear stiffness coefficient and the cubic stiffness coefficient, and obtain the normal compression amount;

[0058] The initial mechanical reaction force model is calculated using the following formula:

[0059]

[0060]

[0061]

[0062] In the formula, This represents the initial mechanical reaction force model. This represents the normal compression amount. This represents the linear stiffness coefficient. This represents the cubic stiffness coefficient. Denotes the first fitted mapping function. This represents the third fitting mapping function. This indicates the temperature during the mixing stage. This represents the integral energy of the torque. This indicates the temperature of the extrusion die. This indicates the extrusion line speed. This indicates the extruder head pressure. This indicates the temperature of the vulcanization zone. This indicates the vulcanization residence time.

[0063] The temperature during the mixing stage is the real-time temperature inside the mixing chamber during the rubber mixing process. It can be obtained through real-time data acquisition by the temperature sensor built into the mixing mill, non-contact measurement by an infrared thermometer, or data reading from the mixing process control system.

[0064] Torque integral energy is the energy value obtained by integrating the torque of the mixer over time during rubber mixing, reflecting the degree of mixing. It can be obtained through real-time torque data acquisition by the mixer's torque sensor followed by integral calculation, automatic statistics by mixing process software, or recording and analysis by a data acquisition system.

[0065] The extrusion die temperature is the temperature at the extruder die during the rubber extrusion process. It can be obtained through data collection by a thermocouple sensor built into the die, multi-point measurement by a temperature monitoring device, or data export from the extruder temperature control system.

[0066] Extrusion line speed is the output speed during the extrusion production of rubber sealing strips. It can be obtained in real time through production line encoders, non-contact measurement with laser velocimeters, or by reading the set value from the extruder control system.

[0067] Extruder head pressure is the pressure at the extruder head during the rubber extrusion process. It can be obtained through a pressure sensor built into the extruder head, a pressure transmitter for measurement, or data extraction from the extrusion process monitoring system.

[0068] The temperature in the vulcanization zone refers to the temperature inside the vulcanization furnace during the vulcanization process of the rubber sealing strip. It can be obtained through a built-in temperature sensor array within the vulcanization furnace, point-to-point measurement with an infrared thermometer, or data retrieval from the vulcanization process control system.

[0069] The vulcanization residence time is the effective time that the rubber sealing strip undergoes vulcanization treatment in the vulcanizing furnace. It can be obtained through calculation based on the extrusion line speed and the effective length of the vulcanizing furnace, real-time recording by a timer, or records in production process documents.

[0070] The linear stiffness coefficient is a linear coefficient that characterizes the compressive stiffness of the sealing strip during the small deformation stage, reflecting the mechanical response of the sealing strip during initial compression.

[0071] The third stiffness coefficient is a nonlinear coefficient that characterizes the compressive stiffness of the sealing strip during the large deformation stage, reflecting the stiffness change trend of the sealing strip under large compression.

[0072] Normal compression is the amount of deformation of the sealing strip along the normal direction under compressive load. It can be obtained through displacement sensors on a universal testing machine, non-contact measurement with a laser displacement gauge, or precise measurement with a displacement grating ruler.

[0073] The first fitting mapping function is a function that establishes a quantitative relationship between the process parameters of the entire process of mixing, extrusion, and vulcanization and the linear stiffness coefficient.

[0074] The third fitting mapping function is a function that establishes a quantitative relationship between the process parameters of the entire process of mixing, extrusion, and vulcanization and the third stiffness coefficient.

[0075] The initial mechanical reaction force model is a mathematical model based on linear stiffness coefficients and cubic stiffness coefficients, describing the relationship between the normal compression of the sealing strip and the mechanical reaction force.

[0076] In detail, the mapping relationship between process parameters and stiffness coefficients is achieved through a first and a third fitting mapping function. Specifically, a multivariate polynomial fitting method is used, with seven process parameters, including mixing stage temperature, torque integral energy, and extrusion die temperature, as independent variables, and linear and cubic stiffness coefficients as dependent variables. Multiple sets of process parameter and corresponding stiffness coefficient data are collected through experimental design, and the least squares method is used for parameter identification to establish quantitative correlations. For example, the first fitting mapping function can be in cubic polynomial form, including linear, quadratic, and interaction terms of the process parameters. By fitting more than 30 sets of experimental data, the goodness of fit of the mapping relationship is ensured to be greater than 0.9, meeting the accuracy requirements of engineering calculations. The cubic nonlinear initial mechanical reaction force model uses a superposition of linear and cubic terms, which accurately reflects the increasing stiffness characteristics of the sealing strip due to cross-sectional geometric nonlinearity and the hyperelasticity of the rubber material, while avoiding the computational complexity of complex constitutive models. For example, when the normal compression is 2 mm, the corresponding mechanical reaction force can be directly obtained through the superposition of linear and cubic terms without the need for additional finite element simulation. The non-negative constraint logic of the stiffness coefficient is implemented through the projection algorithm during the fitting process. When the fitting result shows negative stiffness, it is automatically corrected to 0 to ensure that the mechanical reaction force output by the model increases monotonically with the normal compression amount, which conforms to the mechanical behavior of the sealing strip during actual service. For example, if the fitting result of the third stiffness coefficient is -0.5 N / m³, it can be automatically corrected to 0 to avoid the non-physical phenomenon of the reaction force decreasing as the compression amount increases.

[0077] In detail, the fitting mapping function is preferably a multivariate cubic polynomial. The independent variables include seven process parameters: mixing stage temperature, torque integral energy, extrusion die temperature, extrusion linear speed, extruder head pressure, vulcanization zone temperature, and vulcanization residence time, as well as the quadratic terms and pairwise interaction terms of each parameter. The dependent variables are the linear stiffness coefficient and the cubic stiffness coefficient. The parameter identification adopts the least squares method. The objective function is to minimize the sum of the squares of the experimentally measured stiffness coefficients and the model predicted values. The constraint condition is that both the linear stiffness coefficient and the cubic stiffness coefficient are greater than or equal to 0. The polynomial coefficients are solved by matrix operations or numerical optimization algorithms. For example, the mapping function of the linear stiffness coefficient can be expressed as a linear combination of the linear, quadratic, and interaction terms of each process parameter. The specific coefficient values ​​are obtained by fitting more than 30 sets of experimental data. The detailed procedure for the CLD test is as follows: Samples with a length of 200 mm are cut at three points along the length of the sealing strip segment, from the beginning to the end. Both ends of the sample are fixed with clamps. The ambient temperature is controlled at 23±2 degrees Celsius and the relative humidity is 50±5%. A universal testing machine is used for displacement-controlled compression at a compression speed of 10 mm / min. The compression range is from 0 to 60% of the free height of the bubble tube. Load-displacement data during the compression process are recorded in real time. Each sample is tested three times, and the average value is taken as the CLD data for that location. The calculation method for torque integral energy is as follows: Real-time torque data is collected by the torque sensor of the mixing mill at a frequency of 1 Hz. The integration time interval is from the addition of rubber raw materials to the mixing mill until the end of mixing. The integration algorithm adopts the trapezoidal integration method. For example, if during a certain mixing process, the torque linearly increases from 0 Nm to 50 Nm in 0 to 10 seconds, remains constant at 50 Nm in 10 to 30 seconds, and linearly decreases to 0 Nm in 30 to 40 seconds, then the torque integral energy is (50 × 10) / 2 + 50 × 20 + (50 × 10) / 2 = 1500 Nm / s. The calculation logic for vulcanization residence time is as follows: Vulcanization residence time is equal to the effective vulcanization zone length of the vulcanizing furnace divided by the extrusion linear speed. The effective vulcanization zone length refers to the length of the area in the vulcanizing furnace where the temperature reaches the set vulcanization temperature ±5 degrees Celsius. For example, if the effective vulcanization zone length of the vulcanizing furnace is 6 meters and the extrusion linear speed is 0.5 meters per minute, then the vulcanization residence time is 6 divided by 0.5, which equals 12 minutes.

[0078] Preferably, the normal compression path and tangential relative displacement during the service phase are extracted in segments, including:

[0079] Obtain the static initial gap, contact start angle, initial door angle, real-time door angle, bubble tube height, door angular velocity, hinge unit vector, relative hinge vector, tangential unit vector, and sampling period;

[0080] The normal compression path and the tangential relative displacement are calculated using the following formulas:

[0081]

[0082]

[0083]

[0084] From the above The normal compression paths are generated in chronological order;

[0085]

[0086]

[0087]

[0088] In the formula, Indicates the coefficient of variation. This indicates the static initial gap. Indicates the initial gate angle, Indicates the contact start angle, Indicates dynamic gap, Indicates the real-time gate angle, This indicates the real-time compression amount. Indicates the height of the bubble tube. Represents relative velocity. Indicates the angular velocity of the gate. Denotes the hinge unit vector. Represents the relative hinge vector, Indicates tangential velocity, This represents the tangential unit vector. This indicates the tangential relative displacement. Representing discrete time points, This indicates the sampling period.

[0089] The static initial gap is the static door gap between the weatherstripping and the car body after the car door has been adjusted. It can be obtained by scanning around the perimeter with a laser displacement gauge, measuring at multiple points with a feeler gauge, or extracting from a computer-aided design model.

[0090] The initial contact angle is the door angle at which the weatherstripping first contacts the vehicle body. It can be obtained through a slow door closing test combined with angle sensor data acquisition, door angle and gap correlation measurement, or visual recognition of the moment of contact.

[0091] The initial door angle is the initial angle reference value when the door begins to close. It can be obtained through zero-position calibration of the angle sensor, calibration of the door's fully open position, or setting of a computer-aided design model.

[0092] Real-time door angle is the instantaneous angle at any moment during the door closing process. It can be obtained through vehicle controller LAN signal acquisition, real-time measurement by angle sensors, or calculation by a vision tracking system.

[0093] The bubble tube height is the vertical height of the sealing strip bubble tube in its free state. It can be obtained through cross-sectional slicing measurement, laser diameter measurement, or extraction from computer-aided design drawings.

[0094] Door angular velocity is the rate of change of the door angle during the closing process of a vehicle door. It can be obtained through real-time differential calculation of door angle data, direct acquisition by angular velocity sensors, or export of signals from the vehicle controller's local area network.

[0095] The hinge unit vector is a unit vector representing the direction of the hinge axis of a car door. It can be obtained through extraction from computer-aided design models, calculation after physical measurement of the hinge axis, or derivation through coordinate system transformation.

[0096] The relative hinge vector is the position vector of a point on the door seal relative to the hinge axis. It can be obtained by extracting coordinates from a computer-aided design model and calculating after measuring physical points.

[0097] The tangential unit vector is the unit vector along the tangent direction of the sealing strip's circumference. It can be obtained through computer-aided design path fitting, local geometric analysis of the cross-section, or coordinate system projection derivation.

[0098] The sampling period is the time interval for collecting data such as door angle and speed. It is preferably 0.005 seconds to balance data acquisition accuracy and computational efficiency. A sampling frequency of 200 Hz can completely capture the transient process of the door closing.

[0099] The variation coefficient is a proportionality coefficient that characterizes the relationship between the change in door angle and the dynamic gap.

[0100] Dynamic clearance is the instantaneous gap between the sealing strip and the car body during the door closing process.

[0101] Real-time compression is the actual compression deformation of the sealing strip at any given moment.

[0102] The normal compression path is a time-series data set in which the real-time compression amount changes over time.

[0103] Relative speed is the speed of movement of the point represented by the door seal relative to the car body.

[0104] Tangential velocity is the component of relative velocity along the tangential direction of the sealing strip.

[0105] Tangential relative displacement is the amount of relative slippage between the sealing strip and the vehicle body along the tangential direction.

[0106] In detail, the calculation logic for normal compression is to derive the variation coefficient by the difference between the static initial gap, the initial door angle, and the contact start door angle, establishing a linear relationship between the dynamic gap and the door angle. Then, the upper limit of the difference between the bubble tube height and the dynamic gap is used as the real-time compression. This design eliminates the need to embed displacement sensors in the sealing strip, indirectly obtaining the compression load path through the door kinematic parameters, which aligns with the actual implementation scenarios in automotive engineering. For example, if the static initial gap is 8 mm, the initial door angle is 30 degrees, and the contact start door angle is 5 degrees, the variation coefficient can be calculated as -0.32 mm per degree. When the real-time door angle is 10 degrees, the dynamic gap is 8 plus (10 minus 30) multiplied by (-0.32) equals 14.4 mm. If the bubble tube height is 12 mm, the real-time compression is taken as 0, indicating that the sealing strip has not yet made contact. The derivation method of tangential relative displacement is based on the representative point velocity of the hinge geometric decomposition. The displacement is obtained by integrating the tangential velocity, which solves the industry pain point that the tangential load of the sealing strip is difficult to measure directly. For example, the hinge unit vector is in the vertical direction, and the relative hinge vector is in the horizontal direction. The cross product of the two gives the tangential velocity direction. Combined with the door angular velocity, the tangential velocity can be calculated. Then, the tangential relative displacement is obtained by accumulating the samples over the sampling period. The definition and calibration of the initial door angle are the basis for segmented load extraction. The door angle when the gap is first zero is recorded through a slow door closing test, which provides key boundary conditions for the dynamic gap model and ensures the accuracy of the normal compression path calculation.

[0107] In detail, the hinge unit vector and relative hinge vector are obtained using a computer-aided design model. The specific steps are as follows: Open the door and hinge assembly model in the 3D design software, determine the coordinates of the two endpoints of the hinge axis, calculate and normalize the direction vector of the line connecting the two points to obtain the hinge unit vector; select the midpoint of the sealing strip segment length as a representative point, extract the coordinate difference of this point relative to the hinge axis endpoint to obtain the relative hinge vector. During the extraction process, it is necessary to ensure that the coordinate system is consistent with the vehicle body coordinate system. The measuring device for the initial door angle of contact uses a high-precision angle sensor with an accuracy requirement of ±0.1 degrees. The specific measurement steps are as follows: Install the angle sensor at the door hinge, close the door slowly at a speed of 0.5 degrees per second, and simultaneously monitor the gap between the sealing strip and the vehicle body using a laser displacement meter. When the laser displacement meter detects that the gap first becomes 0, record the reading of the angle sensor at this time, which is the initial door angle of contact. Repeat the measurement 3 times and take the average value. The calibration method for the dynamic gap model involves correcting the variation coefficient through two-point calibration. The specific steps are as follows: Select two known door angle positions, measure the corresponding dynamic gaps, substitute the door angle and gap data into the dynamic gap formula, establish a system of two linear equations, and solve to obtain the accurate variation coefficient. For example, selecting door angles of 10 degrees and 20 degrees, the measured dynamic gaps are 14.4 mm and 11.2 mm respectively. Correcting the variation coefficient ensures that the deviation between the model's predicted value and the measured value is less than 0.1 mm. The integration boundary for the tangential relative displacement is from the moment the sealing strip first contacts to the moment the latch closes. The integration start time is the time point corresponding to the initial door angle contact, and the termination time is the latch closure time when the door angle no longer changes. The integration process uses the trapezoidal integration method to ensure the accuracy of the displacement calculation. For example, with a sampling period of 0.005 seconds and a tangential velocity of 0.02 meters per second at a certain moment, the displacement increment at that sampling point is 0.02 multiplied by 0.005 equals 0.0001 meters. Accumulating these over time yields the total tangential relative displacement.

[0108] Preferably, the peak pressure increment is calculated based on the geometric parameters and the normal compression path to generate an aerodynamic load factor, and the actual normal load is calculated based on the aerodynamic load factor and the initial mechanical reaction model, including:

[0109] Obtain the volume factor and maximum compressibility;

[0110] Obtain the compression rate of the real-time compression amount;

[0111] The aerodynamic loading coefficient and the actual normal load are calculated using the following formulas:

[0112]

[0113]

[0114]

[0115]

[0116]

[0117]

[0118] In the formula, Indicates real-time gas volume. This indicates the effective gas volume of the bubble tube. This represents the volume coefficient. This indicates the real-time compression amount. Indicates the height of the bubble tube. Represents the volume mapping coefficient. This indicates the real-time air pressure increment. This represents the pressure relief time constant. This indicates the ambient reference pressure. This indicates the rate of change of the amount of compression. This represents the peak pressure increment. This represents the aerodynamic load factor. This indicates the effective pressure-bearing area. This indicates the maximum compression amount. This represents the initial mechanical reaction force model corresponding to the maximum compression. This represents the actual normal load. This represents the initial mechanical reaction force model corresponding to the real-time compression amount. Represents a discrete time point.

[0119] The volume factor is a coefficient characterizing the linear proportion of the bubble tube volume to the normal compression. It is determined through finite element analysis of the cross section or actual compression tests, and is preferably between 0.3 and 0.8. The actual volume change is measured when the bubble tube compression reaches 30% of its free height, and the linear proportionality coefficient is obtained by fitting the data.

[0120] Maximum compression is the maximum normal compression deformation of the sealing strip during a single door closing event.

[0121] Real-time gas volume is the actual volume of air that the sealed gas tube can hold at any given time after being compressed.

[0122] The volume mapping coefficient is a geometric coefficient that converts the change in normal compression into a change in bubble volume.

[0123] Compression rate of change is the rate at which real-time compression changes over time, characterizing the speed of the compression process.

[0124] Real-time pressure increment is the increase in air pressure inside the bubble tube relative to the ambient reference pressure at any given moment.

[0125] Peak pressure increment is the maximum real-time pressure increment during a single door closing event.

[0126] The aerodynamic load factor is the amplification ratio of aerodynamic load to mechanical compression reaction force, quantifying the modulation effect of fluid-structure interaction on normal load.

[0127] The true normal load is the total normal load resulting from the superposition of the mechanical reaction force and the aerodynamic load experienced by the sealing strip during service.

[0128] In detail, the real-time gas volume compression correction model, based on the volume factor, correlates the effective gas volume in the bubble tube under free state with the real-time compression rate. It describes the volume change during compression through a linear proportional relationship. This design is specifically adapted to the hollow structure of automotive rubber sealing strip bubble tubes, avoiding pressure calculation errors caused by treating the volume as a fixed value. For example, if the effective gas volume of the bubble tube is 1.2 × 10⁻⁵ cubic meters, the volume factor is 0.5, and the bubble tube height is 12 mm, when the real-time compression rate is 6 mm, the real-time gas volume is 1.2 × 10⁻⁵ multiplied by (1 - 0.5 × 6 / 12) equals 9 × 10⁻⁶ cubic meters, which conforms to actual compression laws. The first-order ODE solution for the pressure increment establishes a transient pressure change equation by coupling the decompression time constant, environmental reference pressure, volume mapping coefficient, and compression rate of change. This quantifies the dynamic balance between bubble tube compression and decompression, achieving engineering-grade accuracy without complex computational fluid dynamics simulations. The aerodynamic load factor is defined as the product of the effective pressure-bearing area and the peak air pressure increment, divided by the mechanical reaction force at maximum compression. This quantifies the aerodynamic effect into a coefficient that can be directly used for load calculation, solving the problem of deviation in real load assessment caused by neglecting aerodynamic loads in traditional methods. The superposition logic of the real normal load directly adds the mechanical reaction force and the aerodynamic load, closely matching the actual stress state of the sealing strip during service. For example, when the mechanical reaction force is 50 N and the aerodynamic load is 10 N, the real normal load is 60 N, ensuring the accuracy of subsequent friction work calculations.

[0129] In detail, the method for determining the volume coefficient employs a combination of cross-sectional finite element analysis and physical experiments. The specific steps are as follows: A cross-sectional model of the bubble tube is established in 3D finite element software; a compression amount from 0 to 60% of the free height of the bubble tube is applied to simulate the volume change under different compression amounts; simultaneously, physical sealing strip bubble tube samples are cut and subjected to compression tests with the same compression amount on a universal testing machine, and the actual volume change is measured using the displacement method; the finite element results are compared with the experimental results, and a linear volume coefficient is obtained by fitting, ensuring that the fitting error is less than 5%. The calculation of the compression rate of change employs a first-order difference combined with low-pass filtering. The specific steps are as follows: For the time-series data of real-time compression, the difference between two adjacent sampling points is divided by the sampling period to obtain the original rate of change; the original rate of change is filtered using a 20 Hz low-pass filter to remove high-frequency noise. For example, with a sampling period of 0.005 seconds, and compression amounts of 2 mm and 2.05 mm at adjacent sampling points, the original rate of change is 10 mm / s. After filtering, a smooth compression rate of change is obtained. The numerical solution algorithm for atmospheric pressure ODE adopts the fourth-order Runge-Kutta method. The specific steps are as follows: the atmospheric pressure change equation is discretized into an iterative formula with a time step equal to the sampling period. The initial atmospheric pressure is input as 0, and the real-time atmospheric pressure increment at each sampling point is calculated sequentially. A convergence condition is set so that the difference in atmospheric pressure increment between adjacent iteration steps is less than 0.1 Pa to ensure numerical stability. For example, with a sampling period of 0.005 seconds and a depressurization time constant of 1.75 × 10⁻⁷ seconds, the real-time atmospheric pressure change can be obtained quickly through iteration. The extreme value determination range of the peak atmospheric pressure increment is limited to the contact window of the sealing strip, i.e., from the moment of initial contact to the moment of latch closure. The specific steps are as follows: all real-time atmospheric pressure increment data within this time interval are extracted, and the maximum value is selected as the peak atmospheric pressure increment. For example, if the contact window is 0.1 seconds, and the maximum real-time atmospheric pressure increment within this time period is 500 Pa, then this is the peak atmospheric pressure increment.

[0130] Preferably, the tangential energy dissipation of the automotive rubber seal is calculated by combining the actual normal load with the tangential relative displacement, including:

[0131] Obtain the basic static friction coefficient, static friction temperature coefficient, basic dynamic friction coefficient, dynamic friction temperature coefficient, real-time temperature, and calibration speed;

[0132] The tangential energy dissipation and the stick-slip strength coefficient are calculated using the following formula:

[0133]

[0134]

[0135]

[0136]

[0137]

[0138]

[0139] In the formula, Indicates the static friction coefficient. This represents the basic static friction coefficient. This represents the static friction temperature coefficient. This indicates the real-time temperature. This represents the coefficient of kinetic friction. This represents the basic coefficient of kinetic friction. This represents the temperature coefficient of kinetic friction. Indicates the real-time friction coefficient. This indicates the tangential velocity. This indicates the calibrated speed. Indicates real-time tangential force. This represents the actual normal load. This indicates the tangential energy dissipation. and This indicates the tangential relative displacement. and Represents discrete time nodes. Represents the total number of points in the time series. Indicates the viscosity-slip strength coefficient. This represents the initial mechanical reaction force model corresponding to the maximum compression. This indicates the maximum compression amount.

[0140] The basic static friction coefficient is the initial friction coefficient reference value between the surface material and the mating material of the sealing strip under static contact conditions. It can be obtained by static friction testing with a friction testing machine, data acquisition with a surface friction characteristic tester, or determination using standard friction testing methods.

[0141] The static friction temperature coefficient is a coefficient that characterizes the rate of change of the static friction coefficient with temperature. It can be obtained by fitting static friction test data at different temperatures and by conducting temperature-friction coefficient correlation tests.

[0142] The basic dynamic friction coefficient is the initial friction coefficient reference value between the surface material of the sealing strip and the mating material under relative sliding conditions. It can be obtained by performing dynamic friction tests using a friction testing machine, collecting data using a dynamic friction tester, or determining it through standard sliding friction tests.

[0143] The temperature coefficient of kinetic friction is a coefficient that characterizes the rate of change of the coefficient of kinetic friction with temperature. It can be obtained by fitting kinetic friction test data at different temperatures and by conducting temperature-dynamic friction coefficient correlation tests.

[0144] Real-time temperature refers to the instantaneous ambient or surface temperature of the sealing strip during its service life. It can be obtained through real-time acquisition by a temperature sensor, non-contact measurement by an infrared thermometer, or extraction by an ambient temperature recorder.

[0145] The calibration speed is a reference sliding speed used to correct the real-time friction coefficient. It is preferably 1 to 10 mm / s, and the value is selected based on the actual range of the tangential speed of the sealing strip when the car door is opened and closed, so as to ensure the calculation accuracy of the friction coefficient model within the commonly used speed range.

[0146] The static friction coefficient is the actual static friction coefficient between the surface material of the sealing strip and the mating material after taking into account the effect of temperature.

[0147] The coefficient of dynamic friction is the actual sliding friction coefficient between the surface material of the sealing strip and the mating material after taking into account the effect of temperature.

[0148] The real-time friction coefficient is the instantaneous friction coefficient that is dynamically corrected by combining static and dynamic friction characteristics, tangential velocity and calibration velocity.

[0149] Real-time tangential force is the instantaneous frictional force that the sealing strip experiences along the tangential direction during its service life.

[0150] Tangential energy dissipation is the total energy dissipated by the sealing strip due to tangential relative slippage during a single door closing event.

[0151] The stick-slip strength coefficient is the normalized ratio of tangential energy dissipation to mechanical compression energy, used to compare the strength of the stick-slip effect across different scenarios.

[0152] A detailed, temperature-dependent friction coefficient model accurately quantifies the impact of temperature on frictional characteristics through the linear correlation between the basic static friction coefficient and the static friction temperature coefficient, and the basic dynamic friction coefficient and the dynamic friction temperature coefficient, conforming to the physical properties of sealing strip surface materials such as flocking or coatings. The Stribeck-type real-time friction coefficient design combines the exponential relationship between the difference between static and dynamic friction coefficients and tangential velocity to dynamically reflect the continuous change of the friction coefficient during stick-slip, rather than using a fixed value. For example, with a basic static friction coefficient of 0.5, a basic dynamic friction coefficient of 0.3, a static friction temperature coefficient of 0.002, a real-time temperature of 30 degrees Celsius, a tangential velocity of 2 mm / s, and a calibration velocity of 5 mm / s, the real-time friction coefficient can be calculated as 0.3 + (0.5² - 0.3) × exp(-2 / 5) ≈ 0.48, closely matching the actual sliding state. The trapezoidal integral method for tangential energy dissipation accurately quantifies energy dissipation during stick-slip by integrating piecewise the closed-loop trajectory of real-time tangential force and relative tangential displacement and taking the absolute value, avoiding the limitations of force or displacement data at a single moment. The normalized definition of the stick-slip strength coefficient is the ratio of tangential energy dissipation to the product of mechanical reaction force and maximum compression under maximum compression. This solves the problem of incomparable energy dissipation indicators caused by differences in size or stiffness of sealing strips of different models and batches, and provides a unified scale for fatigue driving force.

[0153] In detail, the calibration procedure for the friction coefficient model parameters adopts a three-temperature, three-speed combined test. The specific steps are as follows: standard friction specimens are prepared by cutting the surface material of the sealing strip and the mating material (car paint or glass). Reciprocating friction tests are conducted at three temperature environments: -20°C, 23°C, and 60°C, with sliding speeds of 1 mm / s, 10 mm / s, and 100 mm / s respectively. Friction force and speed data are recorded in real time. The basic static friction coefficient, static friction temperature coefficient, basic dynamic friction coefficient, and dynamic friction temperature coefficient are obtained through linear fitting. Each test combination is repeated three times, and the average value is taken to ensure parameter reliability. The real-time temperature is collected on the surface of the contact area between the sealing strip and the vehicle body. Specifically, a miniature temperature sensor is attached to the contact surface of the sealing strip. The sensor accuracy requirement is ±0.5°C. The sampling frequency is consistent with the sampling frequency of tangential velocity and displacement to ensure the time synchronization of temperature data and load data. The numerical accuracy control of tangential energy consumption integration adopts an integration step size consistent with the sampling period, i.e., the integration step size is equal to the data acquisition time interval. If the tangential displacement reverses during integration, integration is still performed according to the actual trajectory to ensure that the energy calculation is complete and the integration error is controlled within 5%. The calibration speed is based on the statistical analysis of the tangential speed range of the sealing strip when the door is opened and closed for different vehicle models. The median value of the commonly used speed range is taken. For example, the statistics show that the tangential speed is mostly between 0.5 and 8 mm / s, so the calibration speed is preferentially set to 5 mm / s.

[0154] Preferably, the aerodynamic loading coefficient and the tangential energy dissipation are used as input conditions to establish an internal degradation state, and the initial mechanical reaction force model is updated based on the internal degradation state to generate an updated reaction force model, as well as compressive stress relaxation parameters, including:

[0155] Obtain activation energy, ozone sensitivity constant, humidity sensitivity constant, load index, ozone concentration, relative humidity, energy consumption index, linear degradation constant, and cubic degradation constant;

[0156] The internal degradation state, the updated reaction force model, and the compressive stress relaxation parameters are calculated using the following formulas:

[0157]

[0158]

[0159]

[0160]

[0161]

[0162]

[0163]

[0164] In the formula, Indicates the incremental degradation. Represents the continuous aging constant. This represents the activation energy. Represents the gas constant. This indicates the real-time temperature. This represents the ozone sensitivity constant. This indicates the ozone concentration. Indicates reference ozone. This represents the humidity sensitivity constant. This refers to the relative humidity. This represents the actual normal load. Indicates the load reference. This indicates the load index. Indicates the sampling period. Indicates the incremental degradation due to a jump. Represents the step fatigue constant. This indicates the tangential energy dissipation. Indicates energy consumption benchmark, This indicates the energy consumption index. This indicates the internal degradation state. Indicates the linear stiffness after attenuation. Represents the linear stiffness coefficient. Represents the linear degradation constant. Indicates the third stiffness after attenuation. Represents the third stiffness coefficient. This represents the third degradation constant. This refers to the updated reaction force model. Indicates the normal compression. This represents the compressive stress relaxation parameter. Represents the relaxation degradation constant. Represents discrete time nodes. Indicates the event sequence number.

[0165] Activation energy is an energy parameter characterizing the temperature sensitivity of the aging reaction of rubber materials. It can be obtained through differential scanning calorimetry measurement, accelerated aging test data fitting, or by consulting material handbooks.

[0166] The ozone sensitivity constant is a coefficient that quantifies the accelerating effect of ozone concentration on rubber degradation. It is preferably between 0.01 and 0.1, and is determined by fitting the correlation between ozone concentration and degradation rate through aging tests at different ozone concentrations.

[0167] The humidity sensitivity constant is a coefficient that quantifies the accelerating effect of relative humidity on rubber degradation. It is preferably between 0.005 and 0.05, determined by fitting the correlation between humidity deviation and degradation rate through aging tests under different relative humidity environments, and is suitable for the humidity range in which automobiles are used.

[0168] The load index is an index characterizing the degree of influence of the actual normal load on the continuous degradation of rubber. It is preferably between 0.5 and 3, determined by fitting the nonlinear relationship between load and degradation rate through compression stress relaxation tests under different static loads, conforming to the stress aging law of rubber materials.

[0169] Ozone concentration is the instantaneous concentration of ozone in the environment where the sealing strip is in service. It can be obtained through real-time data collection by an ozone sensor, data query from an environmental monitoring station, or measurement by a dedicated gas analyzer.

[0170] Relative humidity is the instantaneous percentage of relative humidity in the service environment of the sealing strip. It can be obtained in real time through humidity sensors, meteorological data queries, or measurement by environmental monitoring equipment.

[0171] The energy dissipation index is an index characterizing the degree of influence of tangential energy dissipation on the jump degradation of rubber. It is preferably between 0.5 and 3, determined by fitting the nonlinear relationship between energy dissipation and degradation increment through fatigue tests at different tangential energy dissipation levels, thus conforming to the damage mechanism of stick-slip fatigue.

[0172] The linear degradation constant is a proportionality constant characterizing the effect of internal degradation state on the decay of the linear stiffness coefficient. It is preferably between 0.1 and 0.8, and is determined by fitting the correlation data between the stiffness coefficient and the degradation state in accelerated aging tests.

[0173] The third degradation constant is a proportionality constant characterizing the influence of the internal degradation state on the attenuation of the third stiffness coefficient. It is preferably between 0.1 and 0.8, consistent with the linear degradation constant, to ensure the coordination between nonlinear stiffness attenuation and linear stiffness attenuation.

[0174] The continuous aging constant is a fundamental constant characterizing the degradation rate of rubber under the combined effects of environmental factors and static load. It is preferably between 1×10⁻⁸ and 1×10⁻⁶, calibrated using long-term static aging test data.

[0175] The step fatigue constant is a fundamental constant characterizing the increase in rubber degradation under a single tangential energy dissipation action. It is preferably between 1×10⁻⁵ and 1×10⁻³, calibrated using data from multiple cyclic stick-slip fatigue tests.

[0176] The load reference is a reference value used to normalize the actual normal load. It is preferably 10 to 100 Newtons, and the median value is taken as the reference by statistically analyzing the typical normal load range in the service of automotive sealing strips.

[0177] The energy consumption baseline is a reference value used to normalize tangential energy consumption. It is preferably 0.1 to 1 joule, and is taken as the midpoint by statistically analyzing the typical tangential energy consumption range of a single door closing event of a car sealing strip.

[0178] The relaxation degradation constant is a proportionality constant characterizing the relationship between the internal degradation state and the compressive stress relaxation parameter. It is preferably between 0.5 and 2, and is determined by fitting compressive stress relaxation test data with the degradation state.

[0179] The continuous degradation increment is the amount of rubber degradation per unit time driven by both environmental factors and static load.

[0180] The jump degradation increment is the amount of rubber degradation driven by tangential energy dissipation during a single door closing event.

[0181] The internal degradation state is a continuous state quantity that comprehensively reflects the destruction of the rubber crosslinking network, the decrease in the recoverability of chain segments, and the generation of microcracks.

[0182] The linear stiffness after attenuation is the actual value of the linear stiffness coefficient of the sealing strip after considering the internal degradation state.

[0183] The third stiffness after attenuation is the actual value of the third stiffness coefficient of the sealing strip after considering the internal degradation state.

[0184] The updated reaction force model is a mathematical model that incorporates the influence of internal degradation state and describes the dynamic relationship between the normal compression of the sealing strip and the mechanical reaction force.

[0185] The compression stress relaxation parameter is a parameter that characterizes the degree of attenuation of the sealing force of the sealing strip under long-term compression, that is, the ratio of the real-time sealing force to the initial sealing force.

[0186] The reference ozone concentration is a benchmark value used to normalize ozone concentration. It is preferably 50 ppb (parts per billion), and is determined based on the statistical average ozone concentration in commonly used automotive service environments to ensure comparability after ozone concentration normalization.

[0187] In detail, the innovative dual-drive renewal model of internal degradation divides rubber degradation into continuous environmental driving and abrupt event driving. The continuous driving part integrates the synergistic effects of temperature, ozone, humidity, and static load, while the abrupt event driving part focuses on the instantaneous damage caused by tangential energy dissipation. This design aligns with the actual service characteristics of automotive sealing strips, which continuously bear environmental stress and experience fatigue loads with each door closure. For example, when the sealing strip is parked, it only experiences continuous degradation increments due to environmental factors, while when the door is closed, it experiences additional abrupt degradation increments due to tangential energy dissipation. The superposition of these two factors accurately reflects the degradation process throughout the entire life cycle. The coupled amplification model of environmental factors quantifies the synergistic accelerating effect of ozone and humidity through the superposition of linear terms, avoiding the limitations of calculating individual factors independently. For example, when the ozone concentration is twice the reference value and the relative humidity is 50% higher than the baseline value, the environmental amplification factor is (1+0.05×1)×(1+0.02×1)=1.123, which accurately reflects the combined impact of multiple environmental factors. The degradation attenuation logic of the stiffness coefficient is achieved through the product of the internal degradation state and the degradation constant, ensuring that the stiffness attenuation is directly related to internal structural damage. For example, when the internal degradation state is 0.3 and the linear degradation constant is 0.5, the linear stiffness coefficient attenuates to 70% of its initial value, which conforms to the physical law that the stiffness of rubber materials gradually decreases after aging. The exponential mapping between the compressive stress relaxation parameter and the internal degradation state adopts an exponential function form, which can accurately describe the nonlinear characteristics of the sealing force attenuation. For example, when the internal degradation state is 0.2 and the relaxation degradation constant is 1, the compressive stress relaxation parameter is exp(-1×0.2) = 0.818, that is, the sealing force attenuates to 81.8% of its initial value.

[0188] In detail, the method for identifying model parameters adopts accelerated aging tests combined with compressive stress relaxation tests. The specific steps are as follows: Select sealing strip samples from the same batch and conduct combined accelerated aging tests at three different temperatures (40 degrees Celsius, 60 degrees Celsius, and 80 degrees Celsius), three different ozone concentrations (25 ppb, 50 ppb, and 100 ppb), three different relative humidities (30%, 50%, and 70%), and three different static loads (50%, 100%, and 150% of the design load). At the same time, the compressive stress relaxation parameters and stiffness coefficients are measured at different aging stages. The test data are fitted using the least squares method to minimize the deviation between the model-predicted degradation state and the compressive stress relaxation parameters and the measured values. All model parameters, such as activation energy and ozone sensitivity constant, are then obtained. The goodness of fit must be greater than 0.9. The ozone concentration and relative humidity data acquisition equipment uses dedicated sensors with an accuracy of ±5%. Specifically, the sensors are mounted on the vehicle body sheet metal near the sealing strip. The sensor sampling frequency is consistent with the load data sampling frequency (200 Hz). Data preprocessing uses a first-order low-pass filter to remove high-frequency noise, ensuring the stability and synchronization of environmental data. The load and energy consumption benchmarks are determined using a statistical method. The specific steps are as follows: collect the normal load and single-closing tangential energy consumption data of the sealing strips for 10 different vehicle models. After removing the maximum and minimum values, the average value is taken as the benchmark. For example, if the average normal load is 50 N and the average tangential energy consumption is 0.5 Joules, then the load benchmark is 50 N and the energy consumption benchmark is 0.5 Joules, ensuring that the normalized data are within a reasonable range of 0.1 to 10. The initial value of the internal degradation state is set to 0 (no degradation when manufacturing is completed). The boundary condition is set so that the maximum value of the internal degradation state does not exceed 1.2. When the calculated value exceeds this boundary, it is automatically truncated to 1.2 to avoid the stiffness coefficient decaying to a negative value. For example, when the calculated value of the internal degradation state is 1.3, it is automatically corrected to 1.2. At this time, the linear stiffness coefficient decays to (1-0.5×1.2)=40% of the initial value, still maintaining a reasonable mechanical response.

[0189] Preferably, the minimum effective compression amount that satisfies the minimum contact pressure is calculated based on the updated reaction force model and the compression stress relaxation parameters, and the maximum effective compression deformation margin of the automotive rubber sealing strip is output according to the minimum effective compression amount, including:

[0190] Obtain the minimum contact pressure, effective contact width, relaxation compensation weight, degradation compensation weight, aerodynamic compensation weight, and stick-slip compensation weight;

[0191] The minimum effective compression and the maximum effective compression allowance are calculated using the following formulas:

[0192]

[0193]

[0194]

[0195]

[0196]

[0197] In the formula, Indicates the average contact pressure within the segment. This refers to the updated reaction force model. Indicates the effective contact width, Indicates the length of segment-level participation. This represents the minimum effective compression amount. This indicates the minimum contact pressure. Indicates the minimum required compression. This represents the relaxation compensation weight. This represents the compressive stress relaxation parameter. This represents the degradation compensation weight. This indicates the internal degradation state. This represents the aerodynamic compensation weight. This represents the aerodynamic load factor. This represents the stick-slip compensation weight. Indicates the viscosity-slip strength coefficient. Indicates the design pre-compression amount. Indicates the height of the bubble tube. Indicates the static initial gap. This represents the maximum effective compressive deformation allowance.

[0198] The minimum contact pressure is the minimum average contact pressure required to ensure the sealing strip achieves its waterproof and wind noise control functions. It is preferably between 8 and 20 kPa, determined through vehicle bench testing based on the waterproof, dustproof, and wind noise control targets of automotive sealing strips, and is suitable for the sealing function requirements of most vehicle models.

[0199] The effective contact width is the effective width of the contact area between the sealing strip and the vehicle body. It can be obtained through cross-sectional slicing measurement, extraction from computer-aided design drawings, or indentation testing.

[0200] The relaxation compensation weight is a proportional coefficient that quantifies the amount of compression required to compensate for the decrease in sealing force caused by the relaxation of compressive stress. It is preferably between 0.1 and 1.0, and is determined by fitting the correlation data between sealing force decrease and compression amount in accelerated aging tests.

[0201] The degradation compensation weight is a proportional coefficient that quantifies the amount of compression required to compensate for performance degradation caused by internal degradation. It is preferably between 0.1 and 1.0, consistent with the relaxation compensation weight, to ensure that the compensation amount is coordinated with the internal degradation state.

[0202] The aerodynamic compensation weight is a proportional coefficient that quantifies the impact of aerodynamic load on effective compression. It is preferably between 0.05 and 0.5, determined through sealing function tests under different aerodynamic load coefficients to match the actual degree of aerodynamic effect.

[0203] The stick-slip compensation weight is a proportional coefficient that quantifies the energy dissipation from stick-slip to compensate for the compression required to reduce fatigue damage. It is preferably between 0.05 and 0.5, determined by fitting correlation data between damage severity and compression in stick-slip fatigue tests to closely match the compensation requirements for stick-slip damage.

[0204] The average contact pressure within a segment is the average pressure generated per unit contact width of the sealing strip under specific compression and degradation conditions.

[0205] The minimum effective compression is the minimum amount of compressive deformation that ensures the average contact pressure within the segment is not lower than the minimum contact pressure.

[0206] The first compensation amount is the additional compression required to compensate for the decrease in sealing force caused by the relaxation of compressive stress.

[0207] The second compensation amount is the additional compression required to compensate for performance degradation caused by internal degradation.

[0208] The third compensation amount is the additional compression required to address the load path deviation caused by aerodynamic loading.

[0209] The fourth compensation is the additional compression required to address fatigue damage caused by stick-slip energy loss.

[0210] The minimum required compression is the total compression requirement that meets the sealing function requirements, taking into account the effects of relaxation, degradation, aerodynamic loading, and stick-slip fatigue.

[0211] The design pre-compression amount is the theoretical compression amount set during the design phase after the sealing strip is manufactured and installed on the vehicle.

[0212] The maximum effective compression allowance is the maximum compressible deformation that the sealing strip can still perform to meet the sealing function at the current life cycle stage. It is the minimum difference between the designed pre-compression amount and the required minimum compression amount.

[0213] The detailed solution logic for the minimum effective compression is constrained by the average contact pressure within the segment equaling the minimum contact pressure. It uses a bisection method for numerical solution, directly linking sealing requirements to compression deformation, avoiding the blind reliance on material parameters found in traditional methods. For example, if the minimum contact pressure is 10 kPa, the effective contact width is 5 mm, the segment participation length is 0.6 m, and the updated reaction force model is 30 N at a compression of 2 mm, then the average contact pressure within the segment is 30 divided by (0.005 × 0.6) equals 10 kPa. In this case, 2 mm is the minimum effective compression. The multi-factor compensation formula for the required minimum compression innovatively converts the effects of relaxation attenuation, internal degradation, aerodynamic loading, and stick-slip fatigue into independent compensation terms, which are then superimposed on the minimum effective compression, comprehensively covering performance degradation factors throughout the entire lifecycle. For example, when the relaxation compensation is 0.3 mm, the degradation compensation is 0.2 mm, the aerodynamic compensation is 0.1 mm, and the stick-slip compensation is 0.1 mm, the required minimum compression is the minimum effective compression plus 0.7 mm. The design of the maximum effective compression deformation allowance takes the minimum value of the allowance of each segment around the perimeter, which is in line with the engineering reality that "failure at one point of segment contact affects the overall function of automotive sealing strips". For example, if the allowance of the upper edge of a sealing strip is 1.2 mm, the locking side is 0.8 mm, and the lower edge is 1.0 mm, then the maximum effective compression deformation allowance is taken as 0.8 mm to ensure the reliability of the overall sealing function.

[0214] In detail, the determination of the minimum contact pressure is based on the whole vehicle functional test method. The specific steps are as follows: Select a sealing strip sample of the target vehicle model and conduct a waterproof test (spray pressure 0.3 MPa, lasting 30 minutes) and a wind noise test (vehicle speed 100 km / h, measuring in-vehicle noise) at different contact pressures (5 kPa, 8 kPa, 12 kPa, 15 kPa, 20 kPa). Record the minimum contact pressure that meets the waterproof standard and the wind noise value is below 60 dB. This is the minimum contact pressure. For example, if the test shows that 8 kPa meets the requirements, then 8 kPa is taken as the minimum contact pressure. The effective contact width is measured by cross-sectional slicing combined with optical microscopy. The specific steps are as follows: Cut a 5 mm thick cross-sectional sample from the contact area of ​​the sealing strip, grind it flat, and place it under an optical microscope at 50x magnification to measure the actual width of the contact line. Take the average value of 3 different cross-sections as the effective contact width, and control the measurement accuracy to ±0.1 mm. The calibration procedure for compensation weights employs multi-condition bench testing. The specific steps are as follows: Select sealing strip samples from the same batch and conduct combined tests under three different aging stages, three different aerodynamic loading coefficients, and three different stick-slip energy consumption levels. Record the actual compression required to meet the minimum contact pressure. Obtain each compensation weight through multiple linear regression fitting, ensuring a goodness of fit greater than 0.9. For example, the relaxation compensation weight is 0.5, the degradation compensation weight is 0.4, the aerodynamic compensation weight is 0.2, and the stick-slip compensation weight is 0.2, obtained through fitting the experimental data. The algorithm for solving the minimum effective compression uses a bisection method. The specific steps are as follows: Set the compression search range to 0 to 60% of the bubble tube's free height. Calculate the average contact pressure within the segment at the midpoint of the interval. If it is greater than the minimum contact pressure, reduce the upper boundary; if it is less, reduce the lower boundary. Repeat the iteration until the interval width is less than 0.01 mm. At this point, the midpoint value is the minimum effective compression. For example, with a search range of 0 to 6 mm, after 10 iterations, the minimum effective compression with satisfactory accuracy is obtained.

[0215] like Figure 2 As shown, Figure 2 It demonstrates the positive correlation between the aerodynamic loading coefficient and tangential energy dissipation, and uses bubble size to visually represent the difference in maximum effective compressive deformation margin.

[0216] The horizontal axis represents the aerodynamic load factor, ranging from 0 to 0.8;

[0217] The vertical axis represents tangential energy consumption, measured in joules, ranging from 0 to 6.5.

[0218] The data points show a clear upward trend, indicating that the larger the aerodynamic load factor, the higher the tangential energy consumption of the sealing strip in a single door closing event. This is because aerodynamic load amplifies the normal load, thereby exacerbating tangential friction and energy dissipation.

[0219] The size of the bubble represents the maximum effective compression deformation margin: the larger the bubble, the larger the margin, and the more sufficient the sealing function margin of the sealing strip; conversely, the smaller the bubble, the smaller the margin, and the closer the sealing function is to the critical state.

[0220] Therefore, in regions with high aerodynamic load coefficients, tangential energy consumption increases significantly, and the maximum effective compression deformation margin also increases accordingly. This reflects that under high aerodynamic load conditions, the sealing strip needs a larger compression margin to offset the performance degradation caused by tangential fatigue and aging in order to maintain the sealing function.

[0221] The embodiments of this example have been described above. However, this example is not limited to the specific implementation methods described above. The specific implementation methods described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms based on the guidance of this example, and all of them are within the protection scope of this example.

Claims

1. A method for full lifecycle quality management of automotive rubber sealing strips, characterized in that, include: Obtain the effective gas volume of the bubble tube, the size of the vent hole, and the effective pressure-bearing area of ​​the automotive rubber sealing strip, and generate geometric parameters; Collect process parameters during the manufacturing stage, and establish an initial mechanical reaction force model based on the process parameters; Extract the normal compression path and tangential relative displacement during the service phase in segments; The peak pressure increment is calculated based on the geometric parameters and the normal compression path to generate the aerodynamic load factor, and the actual normal load is calculated based on the aerodynamic load factor and the initial mechanical reaction force model. The tangential energy dissipation of the automotive rubber sealing strip is calculated by combining the actual normal load and the tangential relative displacement. Using the aerodynamic loading coefficient and the tangential energy dissipation as input conditions, an internal degradation state is established, and the initial mechanical reaction force model is updated based on the internal degradation state to generate an updated reaction force model, as well as compressive stress relaxation parameters. Based on the updated reaction force model and the compression stress relaxation parameters, the minimum effective compression amount that satisfies the minimum contact pressure is calculated, and the maximum effective compression deformation margin of the automotive rubber sealing strip is output according to the minimum effective compression amount.

2. The method for full life-cycle quality management of automotive rubber sealing strips according to claim 1, comprising obtaining the effective gas volume of the bubble tube, the size of the vent hole, and the effective pressure-bearing area of ​​the automotive rubber sealing strip, and generating geometric parameters, including: Obtain the segment-level participation length, the cavity area of ​​the free cross section of the bubble tube, the equivalent width of the double seal, and the dimensions of the vent hole including the vent hole radius, vent hole spacing, and equivalent wall thickness of the channel; The effective gas volume of the bubble tube is obtained by multiplying the free cross-sectional cavity area of ​​the bubble tube by the segment participation length. The effective pressure-bearing area is obtained by multiplying the equivalent width between the double seals by the segment-level participation length. The number of vents is obtained by dividing the segment length by the vent spacing. The equivalent flow resistance is obtained based on the flow absorption constant, aerodynamic viscosity, equivalent wall thickness of the channel, number of vents and radius of the vents. The pressure relief time constant is derived from the effective gas volume of the bubble tube, the equivalent flow resistance, and the ambient reference pressure to form the geometric parameters.

3. A method for full lifecycle quality management of automotive rubber sealing strips according to claim 2, comprising collecting process parameters during the manufacturing stage and establishing an initial mechanical reaction force model based on the process parameters, including: The mixing stage temperature, torque integral energy, extrusion die temperature, extrusion line speed, extruder head pressure, vulcanization zone temperature, and vulcanization residence time are obtained as the process parameters. Establish the mapping relationship between the process parameters and the linear stiffness coefficient and the cubic stiffness coefficient; Obtain the normal compression amount; The first value is obtained by multiplying the linear stiffness coefficient by the normal compression. The second value is obtained by multiplying the cubic stiffness coefficient by the cube of the normal compression. The initial mechanical reaction force model is obtained by adding the first value and the second value.

4. A method for full life-cycle quality management of automotive rubber sealing strips according to claim 3, comprising segmented extraction of normal compression paths and tangential relative displacements during the service phase, including: Obtain the static initial gap, contact start angle, initial angle, real-time angle, and bubble tube height; The variation coefficient is obtained by dividing the static initial gap by the difference between the initial door angle and the contact start door angle and then inverting the result. The dynamic gap is obtained by multiplying the difference between the real-time door angle and the initial door angle by the change coefficient and then summing the result with the static initial gap. The maximum value between the difference between the height of the bubble tube and the dynamic gap and zero is taken as the real-time compression amount, and the normal compression path is generated in sequence according to time. Obtain the door angular velocity, hinge unit vector, relative hinge vector, tangential unit vector, and sampling period; The relative velocity is obtained by multiplying the cross product of the hinge unit vector and the relative hinge vector by the door angular velocity. The tangential velocity is obtained by taking the dot product of the relative velocity and the tangential unit vector. The tangential relative displacement is obtained by multiplying the tangential velocity by the sampling period and summing them up sequentially.

5. A method for full life-cycle quality management of automotive rubber sealing strips according to claim 4, comprising calculating the peak air pressure increment based on the geometric parameters and the normal compression path to generate an aerodynamic load factor, and calculating the actual normal load based on the aerodynamic load factor and the initial mechanical reaction force model, including: Obtain the volume factor and maximum compressibility; The real-time gas volume and volume mapping coefficient are calculated based on the bubble tube height, the effective gas volume of the bubble tube, the real-time compression amount, and the volume coefficient. Obtain the compression rate of the real-time compression quantity, and solve the real-time gas pressure increment by combining the decompression time constant, the ambient reference pressure, the volume mapping coefficient, the real-time gas volume and the compression rate of the compression quantity. Take the extreme value as the peak gas pressure increment. The aerodynamic loading coefficient is obtained by dividing the product of the effective pressure-bearing area and the peak pressure increment by the initial mechanical reaction force model corresponding to the maximum compression. The true normal load is obtained by adding the product of the effective pressure-bearing area and the real-time air pressure increment to the initial mechanical reaction force model corresponding to the real-time compression.

6. A method for full life-cycle quality management of automotive rubber sealing strips according to claim 5, comprising calculating the tangential energy dissipation of the automotive rubber sealing strip by combining the actual normal load and the tangential relative displacement, including: Obtain the basic static friction coefficient, static friction temperature coefficient, basic dynamic friction coefficient, dynamic friction temperature coefficient, real-time temperature, and calibration speed; The static friction coefficient is obtained by establishing the mapping relationship between the basic static friction coefficient, the static friction temperature coefficient, and the real-time temperature. The dynamic friction coefficient is obtained by establishing the mapping relationship between the basic dynamic friction coefficient, the dynamic friction temperature coefficient, and the real-time temperature. The real-time friction coefficient is calculated based on the static friction coefficient, the dynamic friction coefficient, the tangential velocity, and the calibrated velocity. The real-time friction coefficient is multiplied by the actual normal load to obtain the real-time tangential force; The real-time tangential force and the relative tangential displacement are subjected to a numerical trapezoidal integral in sequence over time, and the absolute value is taken as the tangential energy dissipation. The stick-slip strength coefficient is obtained by dividing the tangential energy dissipation by the product of the initial mechanical reaction force model corresponding to the maximum compression and the maximum compression.

7. A method for full life-cycle quality management of automotive rubber sealing strips according to claim 6, comprising using the aerodynamic load factor and the tangential energy dissipation as input conditions to establish an internal degradation state, updating the initial mechanical reaction force model based on the internal degradation state to generate an updated reaction force model, and generating compressive stress relaxation parameters, including: The continuous degradation increment is calculated based on activation energy, ozone sensitivity constant, humidity sensitivity constant, load index, real-time temperature, ozone concentration, relative humidity, true normal load, and sampling period. The jump degradation increment is calculated based on the energy consumption index and the tangential energy consumption. The internal degradation state is obtained by adding the continuous degradation increment to the abrupt degradation increment; The updated reaction force model is obtained by attenuating the linear stiffness coefficient and the cubic stiffness coefficient using the internal degradation state, linear degradation constant and cubic degradation constant, and combining them with the normal compression. The compressive stress relaxation parameters are derived based on the internal degradation state and the relaxation degradation constant.

8. A method for full life-cycle quality management of automotive rubber sealing strips according to claim 7, comprising: calculating the minimum effective compression amount to satisfy the minimum contact pressure based on the updated reaction force model and the compression stress relaxation parameters, and outputting the maximum effective compression deformation margin of the automotive rubber sealing strip according to the minimum effective compression amount, including: Obtain the minimum contact pressure, effective contact width, relaxation compensation weight, degradation compensation weight, aerodynamic compensation weight, and stick-slip compensation weight; The average contact pressure within a segment is obtained by dividing the updated reaction force model by the product of the effective contact width and the segment-level participation length. The minimum effective compression is obtained by solving the equation based on the fact that the average contact pressure within the segment is equal to the minimum contact pressure. The relaxation difference is obtained by subtracting the compression stress relaxation parameter from one, and the relaxation difference is multiplied by the relaxation compensation weight to obtain the first compensation amount. The second compensation amount is obtained by multiplying the internal degradation state by the degradation compensation weight; The third compensation amount is obtained by multiplying the aerodynamic load factor by the aerodynamic compensation weight. The fourth compensation amount is obtained by multiplying the stick-slip strength coefficient by the stick-slip compensation weight. The minimum effective compression is obtained by adding the minimum effective compression to the first compensation, the second compensation, the third compensation, and the fourth compensation. The design pre-compression amount is obtained by subtracting the height of the bubble tube from the static initial gap. The difference between the designed pre-compression amount and the required minimum compression amount is calculated, and the minimum value of the difference is taken as the maximum effective compression deformation margin.

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