A method of testing an overload protection viscous damper

Abstract

The present application relates to the technical field of damper testing, and provides an overload protection viscous damper test method, which comprises the following steps: firstly, a sine excitation method is used to cyclically load the overload protection viscous damper at a design speed, and the maximum damping force is determined as a reference force value; then, the overload protection viscous damper is cyclically loaded at multiple preset speed conditions, and the maximum damping force at each condition is determined as a measured value of the overload damping force; wherein, the multiple preset speed conditions are loaded at gradually increased speeds; finally, the deviation between the measured value and the reference force value of the overload damping force is calculated to determine the test result. Through the idea of overload limit approximation, the present application gradually increases the loading speed to the limit overload speed, comprehensively evaluates the overload protection function of the damper through multiple tests, and compares the measured value and the reference force value at each time to effectively evaluate the stability and reliability of the overload protection performance of the damper.

Description

Technical Field

[0001] This invention relates to the field of damper testing technology, and in particular to a test method for an overload protection viscous damper. Background Technology

[0002] In the construction industry, dampers are devices that improve the seismic resistance and structural safety of structures by dissipating energy and reducing vibration. They are widely used in high-rise buildings, long-span bridges, seismic-resistant structures, and special engineering projects. Currently, viscous dampers are mostly used as seismic dampers in buildings. The damping force of a viscous damper is a crucial indicator of vibration reduction, directly affecting the ideal vibration reduction effect of a building. Viscous dampers generate damping force through the flow of liquid in the damping orifice. The magnitude of the damping force is related to velocity; the greater the velocity, the greater the damping force. When the damper is subjected to a large external force and moves at a high velocity, the actual damping force generated by the damper will exceed the design damping force, i.e., damping force overload. Viscous damper damping force exceeding the design value can lead to structural stress imbalance, damage to the damper itself, and may also reduce the overall seismic / wind resistance performance of the building. Currently, conventional viscous dampers cannot limit the increase in damping force. Therefore, in order to solve the problem of overload of damping force in viscous dampers, people have developed overload protection viscous dampers in order to solve the problem of overload of damping force in viscous dampers.

[0003] One of the main performance indicators of overload-protected viscous dampers is controlling damping force overload, achieving "viscous energy dissipation under normal operating conditions and unloading protection under overload conditions." The overload test of the damping force of the overload-protected viscous damper is crucial for verifying the damper's dual functions of "energy dissipation and vibration reduction under normal operating conditions and protection under overload conditions," directly determining structural safety and the damper's service reliability. It ensures that the vibration reduction effect meets expectations. Simultaneously, it assesses the durability and stability of the overload protection structure to prevent protection function failure or false triggering. To ensure the performance consistency of dampers in the same batch, overload performance tests are conducted on the overload dampers before they leave the factory.

[0004] Traditional static loading tests are insufficient to accurately simulate the dynamic response characteristics under seismic loading, and therefore cannot comprehensively evaluate the damping performance of dampers. While dynamic loading tests can better reflect actual working conditions, their high equipment cost and complex operation limit their widespread application. Furthermore, existing testing methods often focus only on the mechanical properties of the damper, neglecting the testing of overload protection functions, and thus failing to comprehensively evaluate the overall performance of the damper. Summary of the Invention

[0005] This invention provides a test method for overload protection viscous dampers, which addresses the problem that existing test methods often only focus on the mechanical properties of the damper, neglecting the detection of overload protection functions and failing to comprehensively evaluate the overall performance of the damper.

[0006] This invention provides a test method for an overload protection viscous damper, comprising: Using the sinusoidal excitation method, the overload protection type viscous damper is cyclically loaded at the design speed, and the maximum damping force at the design speed is determined as the reference force value. The overload protection viscous damper was cyclically loaded under multiple preset speed conditions, and the maximum damping force under each preset speed condition was determined as the measured value of the overload damping force; the loading speed was increased step by step under multiple preset speed conditions. The deviation between the measured value of the overload damping force and the reference force value under each preset speed condition is calculated to determine the test results.

[0007] In one possible implementation, a sinusoidal excitation method is used to cyclically load the overload-protected viscous damper at the design speed, and the maximum damping force at that design speed is determined as the reference force value, including: Using the sinusoidal excitation method, the overload protection viscous damper was subjected to five cycles of loading at the design displacement amplitude under the design speed and design frequency. The maximum damping force of the hysteresis curve at the third cycle was taken as the measured value of the maximum damping force.

[0008] In one possible implementation, the overload-protected viscous damper is cyclically loaded under multiple preset speed conditions, and the maximum damping force under each preset speed condition is determined as the measured value of the overload damping force, including: Using the sinusoidal excitation method, the overload protection viscous damper is subjected to one cyclic loading at the design displacement amplitude under the design speed and design frequency. Immediately after the sinusoidal wave ends, a triangular wave is used to perform three cyclic loadings on the overload protection viscous damper under each preset speed condition. The maximum damping force of the hysteresis curve at the third cycle of each condition is taken as the measured value of the overload damping force.

[0009] In one possible implementation, the loading speeds of the preset speed conditions are sequentially 1.2V0, 1.5V0, 2V0, 3V0, and V... max Where V0 is the design speed.

[0010] In one possible implementation, after employing a sinusoidal excitation method to cyclically load the overload-protected viscous damper at the design speed and determining the maximum damping force at that design speed as the reference force value, the method further includes: Using the sinusoidal excitation method, the overload protection viscous damper was subjected to five cycles of loading under the first design displacement condition at the design speed and design frequency. The maximum damping force and maximum speed of the hysteresis curve during the third cycle of each first design displacement condition were determined. Based on the maximum damping force and maximum velocity corresponding to each first design displacement condition, determine the damping force-velocity fitting curve corresponding to each first design displacement condition; Based on the damping force-velocity fitting curve corresponding to each first design displacement condition, determine the damping coefficient and damping exponent; The area of ​​the hysteresis curve envelope in the third cycle under each first design displacement condition is taken as the measured value of the hysteresis curve area for the corresponding condition. Among them, the displacement amplitude of the first design displacement condition is k times the design displacement amplitude and increases step by step, k∈[0.1,1.0].

[0011] In one possible implementation, a sinusoidal excitation method is used to cyclically load the overload-protected viscous damper at the design speed, and the maximum damping force at that design speed is determined as the reference force value, including: Using the sinusoidal excitation method, the overload protection viscous damper was subjected to five cycles of loading under the second design displacement condition at the design speed and design frequency. The hysteresis curves under each second design displacement condition were plotted. The displacement amplitude of the second design displacement condition is n times the design displacement amplitude and increases progressively, where n∈[30%,100%).

[0012] The average value of the damping force in the two directions of the third cycle under the second design displacement condition of n=100% is taken as the measured value of the maximum damping force and used as the reference force value. The area of ​​the envelope of the hysteresis curve under this cycle is taken as the area of ​​the hysteresis curve. The average value of the damping force in the two directions during the third cycle under each second design displacement condition is taken as the measured value of the damping force under that condition.

[0013] In one possible implementation, the overload-protected viscous damper is cyclically loaded under multiple preset speed conditions, and the maximum damping force under each preset speed condition is determined as the measured value of the overload damping force, including: Using a triangular wave, the overload protection viscous damper was subjected to three cycles of loading under each preset speed condition. The maximum damping force of the hysteresis curve during the third cycle of each condition was taken as the measured value of the overload damping force.

[0014] In one possible implementation, the loading speeds of the preset speed conditions are successively 0.5V0, 0.8V0, V0, 1.5V0, and V... max Where V0 is the design speed, V max This is the maximum overload protection speed.

[0015] In one possible implementation, after employing a sinusoidal excitation method to cyclically load the overload-protected viscous damper at the design speed and determining the maximum damping force at that design speed as the reference force value, the method further includes: Using the sinusoidal excitation method, the overload protection type viscous damper was subjected to five cycles of loading at a preset frequency under the design speed and design displacement amplitude to plot the hysteresis curve. Among them, the loading frequency is gradually increased under the preset frequency condition; 0.5f1≤f≤f2; f is the loading frequency under the preset frequency condition, f1 is the frequency at the effective speed, and f2 is the frequency at the maximum overload protection speed.

[0016] In one possible implementation, the deviation between the measured value of the overload damping force and the reference force value under each preset speed condition is calculated to determine the test results, including: Calculate the absolute value of the difference between the measured value of the overload damping force and the reference force value; Divide the absolute value of the difference by the reference force value to obtain the deviation; When the deviation is less than 15%, the test results of the overload protection viscous damper are qualified.

[0017] Compared to traditional technologies, this invention provides a test method for overload protection viscous dampers. First, a sinusoidal excitation method is used to cyclically load the overload protection viscous damper at a design speed, determining the maximum damping force at that design speed as a benchmark force value. Then, the overload protection viscous damper is cyclically loaded under multiple preset speed conditions, determining the maximum damping force under each preset speed condition as the measured overload damping force value. The loading speed is progressively increased across the multiple preset speed conditions. Finally, the deviation between the measured overload damping force value and the benchmark force value is calculated to determine the test results. This invention, by adopting an overload limit approximation approach, gradually increases the loading speed to the ultimate overload speed. Through multiple tests at different speeds and displacements, the overload protection function of the damper is comprehensively evaluated, solving the problem of incomplete performance evaluation of overload protection viscous dampers in existing technologies. Furthermore, comparing the measured values ​​with the benchmark force value each time effectively evaluates the stability and reliability of the damper's overload protection performance. Attached Figure Description

[0018] Figure 1 This is a flowchart illustrating the implementation of the overload protection viscous damper test method provided in this embodiment of the invention. Figure 2 This is a speed versus damping force fitting test curve provided in an embodiment of the present invention; Figure 3 This is an example of the displacement-time loading curve when a sine wave and a triangular wave are applied together; Figure 4 This is an example of a displacement-time loading curve under sinusoidal loading. Detailed Implementation

[0019] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0020] Figure 1 is an implementation flow chart of the test method for an overload protection viscous damper provided by an embodiment of the present invention. As Figure 1 shown, the method comprises: S110, adopting a sinusoidal excitation method to cyclically load the overload protection type viscous damper at a design speed, and determining the maximum damping force at the design speed as a reference force value; S120, cyclically loading the overload protection type viscous damper under a plurality of preset speed working conditions, and determining the maximum damping force under each preset speed working condition as a measured value of the overload damping force; wherein the loading speeds of the plurality of preset speed working conditions are increased step by step; S130, calculating the deviation between the measured value of the overload damping force and the reference force value under each preset speed working condition, so as to determine the test result.

[0021] In the embodiment of the present invention, the overload protection viscous damper to be tested is fixed horizontally / vertically on an electro-hydraulic servo fatigue testing machine, and the installation of the damper with the loading end of the testing machine, force sensors, displacement sensors and other sensors is completed. Start the testing machine, conduct non-impact smooth loading according to preset sine wave parameters, drive the damper to complete tension-compression reciprocating motion, and keep the loading speed at the design speed V0 throughout the whole process. The first cycle mainly eliminates the connection clearance of the testing machine and the static resistance of the viscous fluid inside the damper, and the data is only used as running-in reference; for the second cycle: the fluid inside the damper enters a dynamic stable flow state, the friction coefficient of the equipment tends to be constant, and the data is used as transition reference; in the third cycle, both the equipment and the damper reach a stable working state, the full damping force-displacement data of this cycle is continuously collected by force sensors and displacement sensors, which is used as core basic data; the 4th and 5th cycles continue to be loaded according to the sine wave, and the peak damping force data of these two cycles are collected, which is used to verify the repeatability and stability of the damping force at the design speed.

[0022] Then the deviation between the measured value of the overload damping force and the reference force value is calculated, and the test result of the overload performance is qualified when the deviation meets the standard. In addition, corresponding standards are set in multiple links or steps of the above test, if the data measured in a certain link or step does not meet the standard, the overload protection viscous damper is unqualified, and the next test is performed if the data meets the standard.

[0023] Earthquake action is often accompanied by suddenness and abrupt changes. Observing typical earthquake waveforms, earthquake action often starts with small micro-tremors in the early stage and suddenly enters the maximum vibration state, lasting for two to three waveforms. At this time, the motion state of the seismic isolation layer changes from micro-motion (or static) to rapid motion to the maximum displacement state. In this abrupt state, the basic form of damper is impact damping. The impact state of the damper will seriously affect its output and stability. At present, damper testing uses sine waves, the change of operating state is relatively slow, and the test conditions are that the first half of the cycle uses low-speed approach, and the return cycle only starts to use normal sine wave motion. There is no testing method or approach for the impact characteristics of the damper.

[0024] Viscous dampers are velocity-dependent dampers, meaning their output force is positively correlated with their operating speed; the higher the speed, the greater the damping force. At impact speeds, the damping force may exceed the normal operating speed (measured damping forces exceed 1.2 to 1.5 times the maximum damping force). Exceeding the damping force can cause significant damage to embedded parts, connecting lugs, building structures, and other related connection components, and this often occurs in the early stages of an earthquake, posing a risk throughout the entire seismic isolation cycle.

[0025] Prior art: CN202411555340.0 discloses a test method for an overload-protected viscous damper. This method increases the loading speed in the second and third tests, and uses the same parameters as the first test in the fourth test. Finally, it compares the deviation between the fourth and first tests. Essentially, it tests whether the damper can still function normally under standard operating conditions after an overload, rather than testing its overload performance.

[0026] This invention comprehensively evaluates the overload protection function of the damper by adopting the approach of overload limit approximation. In addition, during the overload limit approximation process, the measured value of each test is compared with the benchmark value to ensure that the damper can remain stable under different overload conditions, effectively evaluating the stability and reliability of the damper's overload protection performance.

[0027] The method of the present invention will be described below through two embodiments, but these are not intended to be limiting. Furthermore, the methods shown in these two embodiments can be performed individually to test overload-protected viscous dampers, or they can be performed sequentially to perform a more comprehensive test of the overload-protected viscous damper; this is not limited here.

[0028] Example 1: Using a hybrid waveform, the maximum damping force was first tested using a sinusoidal excitation method, and then a triangular wave was used to test the impact overload speed stability and overload damping force.

[0029] In some embodiments, a sinusoidal excitation method is used to cyclically load an overload-protected viscous damper at the design speed to determine the maximum damping force at the design speed as a reference force value. This includes: using a sinusoidal excitation method, performing five cyclic loading cycles on the overload-protected viscous damper at the design displacement amplitude at the design speed and design frequency, and taking the maximum damping force of the hysteresis curve at the third cycle as the measured value of the maximum damping force.

[0030] In this embodiment of the invention, the input displacement is: u = u0sin(ωt), where u0 is the design displacement amplitude; the sinusoidal excitation method drives the damper to perform a smooth tension-compression motion by outputting a simple harmonic reciprocating loading signal. Its speed change law is controllable and the loading state is stable, which can eliminate non-performance factor interference to the greatest extent and accurately simulate the stable working condition of the damper during normal service; the damping force of the viscous damper is positively correlated with the speed. Under a fixed design speed, the maximum damping force in the steady state can objectively reflect its rated working performance. As a reference force value, it can effectively measure the degree of performance deviation under overload conditions.

[0031] At the design speed and design frequency f1, the displacement boundary of the damper's reciprocating motion is limited according to the design displacement amplitude to ensure that the load is within its rated operating range. All test data must be recorded and backed up in real time, including the raw data of 5 cycles, hysteresis curves, and calculation process, to ensure that the test results are traceable and verifiable.

[0032] In some embodiments, the overload protection viscous damper is cyclically loaded under multiple preset speed conditions, and the maximum damping force under each preset speed condition is determined as the measured value of the overload damping force. This includes: before testing the overload characteristics of the test piece, a sinusoidal excitation method is first used to perform one cyclic loading at the design displacement amplitude of the overload protection viscous damper at the design speed and design frequency; and immediately after the sinusoidal wave ends, a triangular wave is used to perform three cyclic loadings on the overload protection viscous damper under each preset speed condition, and the maximum damping force of the hysteresis curve at the third cycle of each condition is taken as the measured value of the overload damping force.

[0033] In some embodiments, the loading speeds of the preset speed conditions are 1.2V0, 1.5V0, 2V0, 3V0, and V... max Where V0 is the design speed.

[0034] In this embodiment of the invention, a hybrid waveform excitation method is employed. The first step uses a sinusoidal excitation method, with an input displacement u = u0sin(ωt) and a loading frequency of f1, performing one cycle of loading. The second step uses a triangular wave loading method, with an input displacement u = u0, employing frequencies of 1.2V0, 1.5V0, 2V0, 3V0, and V... maxThere are 5 working conditions in total, and the load is continuously applied for 3 cycles without interruption. The maximum damping force of the hysteresis curve at the third cycle of each working condition is taken as the measured value of the overload damping force. The deviation between the measured value of the maximum damping force of each working condition and the design maximum damping force should meet the requirement of 15% to be considered qualified.

[0035] In some embodiments, after using the sinusoidal excitation method to cyclically load the overload protection type viscous damper at the design speed and determining the maximum damping force at the design speed as the reference force value, the method further includes: using the sinusoidal excitation method to cyclically load the overload protection type viscous damper at the design speed and design frequency for 5 cycles under the first design displacement condition, determining the maximum damping force and maximum speed of the hysteresis curve in the 3rd cycle of each first design displacement condition; determining the damping force-velocity fitting curve corresponding to each first design displacement condition based on the maximum damping force and maximum speed corresponding to each first design displacement condition; determining the damping coefficient and damping exponent based on the damping force-velocity fitting curve corresponding to each first design displacement condition; and using the area of ​​the envelope of the hysteresis curve in the 3rd cycle of each first design displacement condition as the measured value of the hysteresis curve area of ​​the corresponding condition; wherein, the displacement amplitude of the first design displacement condition is k times the design displacement amplitude and increases progressively, k∈[0.1,1.0].

[0036] In this embodiment of the invention, after completing cyclic loading at the design speed and determining the reference force value using the sinusoidal excitation method, the test method further obtains the core mechanical parameters and energy dissipation characteristics of the damper through sinusoidal excitation tests under multiple displacement conditions.

[0037] Using a sinusoidal excitation method with design speed and design frequency as fixed loading parameters, the overload protection viscous damper was tested sequentially under multiple first design displacement conditions, with each condition undergoing five cycles of loading. The core characteristic of the first design displacement condition is that the displacement amplitude increases progressively by k times the design displacement amplitude, where k ranges from [0.1, 1.0], starting from 10% of the design displacement amplitude and gradually increasing to 100%, forming a complete test range covering small displacements to above-design displacements, ensuring comprehensive capture of the damper performance at different displacement scales. Preferably, the displacement amplitude u1 is taken as 0.1u0, 0.2u0, 0.5u0, 0.7u0, and 1.0u0 for five conditions.

[0038] For each initial design displacement condition, after five cycles of loading, the test data from the third cycle are extracted. During this cycle, the equipment and damper have reached a stable operating state, and the data is the most representative. From the damping force-displacement hysteresis curve of the third cycle, the maximum damping force in the tensile and compressive directions is determined (the absolute value is taken and then averaged), serving as the measured maximum damping force value for this condition. Simultaneously, the maximum velocity of this cycle is calculated by differentiating the displacement-time curve, serving as the measured maximum velocity value for the corresponding condition.

[0039] Based on the measured data of maximum damping force and maximum velocity corresponding to each first design displacement condition, a nonlinear regression method is used for fitting analysis to establish the functional relationship between damping force and velocity under each condition, forming a damping force-velocity fitting curve specific to each first design displacement condition. The functional expression of this fitting curve is: F=C|v| a sign(v) Where v = 2πfA, f is the loading frequency, A is the loading amplitude, F is the theoretical damping force, C is the damping coefficient, a is the damping exponent, and ω = 2πf is the angular frequency.

[0040] Furthermore, for each first design displacement condition, the area enclosed by the damping force-displacement hysteresis curve during the third cycle is calculated, and this area is used as the measured value of the hysteresis curve area under the corresponding condition. The hysteresis curve area directly reflects the single-cycle energy dissipation capacity of the damper under that displacement condition; the larger the area, the higher its vibration reduction efficiency.

[0041] Example 2: The stability of damping force after overload speed was tested by using a sine wave with increasing speed, and the stability of overload performance under impact speed was tested by a separate triangular wave test.

[0042] In some embodiments, a sinusoidal excitation method is used to cyclically load an overload-protected viscous damper at the design speed to determine the maximum damping force at that design speed as the reference force value. This includes: using a sinusoidal excitation method, performing five cyclic loading cycles on the overload-protected viscous damper under the second design displacement condition at the design speed and design frequency, and plotting the hysteresis curve for each second design displacement condition; wherein the displacement amplitude of the second design displacement condition is n times the design displacement amplitude and increases progressively, n∈[30%,100%]; the average value of the damping forces in the two directions of the third cycle result under the second design displacement condition with n=100% is taken as the measured value of the maximum damping force, which is used as the reference force value, and the envelope area of ​​the hysteresis curve under this cycle is taken as the area of ​​the hysteresis curve; the average value of the damping forces in the two directions of the third cycle under each second design displacement condition is taken as the measured value of the damping force under that condition.

[0043] In this embodiment of the invention, a sinusoidal excitation method is used for testing. During the loading process, the design speed and design frequency are kept constant. Multiple second design displacement conditions are constructed by adjusting the displacement amplitude alone, and all conditions undergo five cycles of loading. The displacement amplitude of the second design displacement condition is set to increase progressively in increments of n times the design displacement amplitude, where n ranges from [30%, 100%], starting from 30% of the design displacement amplitude and gradually increasing to 100% (the complete design displacement amplitude). This forms a continuous test range covering low to medium displacements to the design rated displacement, ensuring comprehensive capture of the damping force output characteristics of the damper under different displacement loads. Preferably, n = 30%, 50%, 70%, and 100%.

[0044] For each second design displacement condition, after completing 5 cycles of loading, based on the real-time data collected by the force sensor and displacement sensor, the damping force-displacement hysteresis curve under that condition is plotted. The curve must completely cover the entire stroke of the tension-compression reciprocating motion and clearly show the dynamic relationship between damping force and displacement.

[0045] During the data processing phase, for each second design displacement condition, the test data from the third cycle was extracted as the core analytical basis. In this cycle, the testing machine and damper have completely eliminated initial gaps and fluid stagnation, entering a stable working state, ensuring the highest accuracy and representativeness of the data. For the third cycle of each condition, the maximum tensile and compressive damping forces were read, and the average of their absolute values ​​was taken as the measured damping force value for that second design displacement condition, thus establishing the correspondence between displacement amplitude and damping force.

[0046] The determination of the benchmark force value is based on the second design displacement condition (i.e., the complete design displacement amplitude condition) with n=100%. The maximum tensile and maximum compressive damping forces in the third cycle under this condition are extracted, and the average of their absolute values ​​is calculated. This average value is used as the measured value of the maximum damping force at the design speed and is formally established as the benchmark force value for subsequent overload performance tests. At the same time, the area enclosed by the hysteresis curve in the third cycle under this condition is calculated as a quantitative indicator of the damper's single-cycle energy dissipation capacity at the design speed, providing a reference for the comprehensive evaluation of the damper's vibration reduction performance.

[0047] In some embodiments, the overload protection viscous damper is cyclically loaded under multiple preset speed conditions, and the maximum damping force under each preset speed condition is determined as the measured value of the overload damping force. This includes: using a triangular wave, the overload protection viscous damper is cyclically loaded 3 times under each preset speed condition, and the maximum damping force of the hysteresis curve at the third cycle of each condition is taken as the measured value of the overload damping force.

[0048] In some embodiments, the loading speeds of the preset speed conditions are sequentially 0.5V0, 0.8V0, V0, 1.5V0, and V0. max Where V0 is the design speed, V max This is the maximum overload protection speed.

[0049] In this embodiment of the invention, a triangular wave is used for loading, with an input displacement u=u0, and V values ​​of 0.5V0, 0.8V0, 1.0V0, 1.5V0, and V are used respectively. max There are 5 operating conditions, with 3 cycles of continuous loading without interruption. The maximum damping force of the hysteresis curve at the 3rd cycle of each operating condition is taken as the measured value of the overload damping force. The deviation between the measured maximum damping force and the design maximum damping force should meet the requirement of 15% of the impact overload performance of the overload protection viscous damper. This is considered qualified.

[0050] In some embodiments, after using the sinusoidal excitation method to cyclically load the overload protection type viscous damper at the design speed and determining the maximum damping force at the design speed as the reference force value, the method further includes: using the sinusoidal excitation method to cyclically load the overload protection type viscous damper at the design speed and design displacement amplitude for 5 cycles under a preset frequency condition to plot the hysteresis curve; wherein, the preset frequency condition progressively increases the loading frequency; 0.5f1≤f≤f2; f is the loading frequency of the preset frequency condition, f1 is the frequency at the effective speed, and f2 is the frequency at the maximum overload protection speed.

[0051] In this embodiment of the invention, after completing cyclic loading at the design speed and determining the reference force value using the sinusoidal excitation method, the test method is further extended to multi-frequency operating condition testing to comprehensively evaluate the mechanical response and energy dissipation characteristics of the overload protection viscous damper at different vibration frequencies.

[0052] The test was conducted using a sinusoidal excitation method. During loading, the design velocity and design displacement amplitude remained constant. Multiple preset frequency conditions were constructed by progressively increasing the loading frequency, with each condition undergoing five cycles of loading according to a standard procedure. The frequency range of the preset frequency conditions was strictly limited to 0.5f1 ≤ f ≤ f2, where f is the loading frequency of the current preset frequency condition, f1 is defined as the frequency corresponding to the damper's effective speed (i.e., the critical frequency at which the damper begins to exert its stabilizing vibration reduction effect), and f2 is defined as the frequency corresponding to the maximum overload protection speed (i.e., the limit frequency at which the damper triggers its overload protection function). This frequency range covers the complete frequency range of the damper from normal operation to overload protection, ensuring that the test closely reflects the vibration conditions in actual service. Preferably, the loading frequency was progressively increased to 0.5f1, 0.8f1, 1.0f1, 1.5f1, and f2.

[0053] For each preset frequency condition, during five cycles of loading, damping force and displacement data during the tension-compression reciprocating motion are collected in real time using force and displacement sensors. Based on the full-cycle data, a damping force-displacement hysteresis curve for that frequency condition is plotted. The plotting process must ensure the continuity and completeness of data acquisition, and the curve must clearly show the trajectory of damping force change with displacement in each cycle, including key features such as the peak values ​​of damping force in the tension and compression directions, curve symmetry, and envelope area.

[0054] The five loading cycles for each preset frequency condition follow a unified data acquisition logic: the first two cycles serve as a break-in and transition phase, mainly used to eliminate the connection gap between the equipment and the damper and allow the internal viscous fluid to enter a dynamic stable state; the data is for reference only. The third cycle is the core data acquisition phase, at which point both the equipment and the damper have reached a stable operating state, and the plotted hysteresis curve is used for subsequent core performance analysis. The fourth and fifth cycles serve as a stability verification phase; by comparing the hysteresis curve shape, peak damping force, and envelope area of ​​these two cycles with those of the third cycle, the repeatability and stability of the damper performance at this frequency are evaluated.

[0055] In some embodiments, the deviation between the measured value of the overload damping force and the reference force value under each preset speed condition is calculated to determine the test result, including: calculating the absolute value of the difference between the measured value of the overload damping force and the reference force value; dividing the absolute value of the difference by the reference force value to obtain the deviation; when the deviation is less than 15%, the test result of the overload protection viscous damper is qualified.

[0056] Figure 2 This is a velocity-damping force fitting test curve provided in an embodiment of the present invention. Table 1 is a comparison table of the deviation between the measured data and theoretical data of the overload protection type viscous damper. Figure 3 This is an example of the displacement-time loading curve when a sine wave and a triangular wave are loaded together, that is, the curve obtained after loading using the method in Example 1 above; Figure 4 This is an example of a displacement-time loading curve under sinusoidal loading, that is, the curve obtained after loading using the method in Example 2 above.

[0057] Table 1. Comparison of Measured and Theoretical Data for Overload Protection Viscous Dampers

[0058] In the above embodiments, the descriptions of each embodiment have their own emphasis. Parts not detailed or described in a particular embodiment can be referred to in the relevant descriptions of other embodiments. Unless otherwise specified or in conflict with logic, the terminology and / or descriptions between different embodiments are consistent and can be referenced interchangeably. Technical features in different embodiments can be combined to form new embodiments based on their inherent logical relationships.

[0059] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A test method for an overload protection viscous damper, characterized in that, include: Using the sinusoidal excitation method, the overload protection type viscous damper is cyclically loaded at the design speed, and the maximum damping force at the design speed is determined as the reference force value. The overload protection viscous damper is cyclically loaded under multiple preset speed conditions, and the maximum damping force under each preset speed condition is determined as the measured value of the overload damping force; wherein the loading speed is increased step by step under the multiple preset speed conditions. The deviation between the measured value of the overload damping force and the reference force value under each preset speed condition is calculated to determine the test results; wherein, the deviation is used to reflect the degree of performance deviation under overload conditions; The loading speeds for the preset speed conditions are 1.2V0, 1.5V0, 2V0, 3V0, and V... max Where V0 is the design speed, V max Maximum overload protection speed; Using the sinusoidal excitation method, an overload-protected viscous damper is cyclically loaded at the design speed to determine the maximum damping force at that design speed as the reference force value, including: Using the sinusoidal excitation method, the overload protection viscous damper was subjected to five cycles of loading at the design displacement amplitude under the design speed and design frequency. The maximum damping force of the hysteresis curve at the third cycle was taken as the measured value of the maximum damping force. The overload protection viscous damper was cyclically loaded under multiple preset speed conditions, and the maximum damping force under each preset speed condition was determined as the measured value of the overload damping force, including: Using a sinusoidal excitation method, the overload protection viscous damper is subjected to one cyclic loading at the design displacement amplitude under the design speed and design frequency. Immediately after the sinusoidal wave ends, a triangular wave is used to perform three cyclic loadings on the overload protection viscous damper under each preset speed condition. The maximum damping force of the hysteresis curve at the third cycle of each condition is taken as the measured value of the overload damping force.

2. The test method for overload protection viscous damper according to claim 1, characterized in that, After using the sinusoidal excitation method to cyclically load an overload-protected viscous damper at the design speed and determining the maximum damping force at that design speed as the reference force value, the method further includes: Using the sinusoidal excitation method, the overload protection viscous damper was subjected to five cycles of loading under the first design displacement condition at the design speed and design frequency. The maximum damping force and maximum speed of the hysteresis curve during the third cycle of each first design displacement condition were determined. Based on the maximum damping force and maximum velocity corresponding to each first design displacement condition, determine the damping force-velocity fitting curve corresponding to each first design displacement condition; Based on the damping force-velocity fitting curve corresponding to each first design displacement condition, determine the damping coefficient and damping exponent; The area of ​​the hysteresis curve envelope in the third cycle under each first design displacement condition is taken as the measured value of the hysteresis curve area for the corresponding condition. Wherein, the displacement amplitude of the first design displacement condition is k times the design displacement amplitude and increases progressively, k∈[0.1,1.0].

3. The test method for overload protection viscous damper according to claim 1, characterized in that, Calculate the deviation between the measured overload damping force and the reference force value under each preset speed condition to determine the test results, including: Calculate the absolute value of the difference between the measured value of the overload damping force and the reference force value; The deviation is obtained by dividing the absolute value of the difference by the reference force value; When the deviation is less than 15%, the test result of the overload protection viscous damper is qualified.

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