Method for testing performance of viscous damper with variable damping coefficient

Abstract

The application discloses a performance testing method of a viscous damper with a variable damping coefficient, and comprises the following steps: calculating the basic frequency of the viscous damper with the variable damping coefficient; obtaining the limit displacement X of the viscous damper with the variable damping coefficient; obtaining the first-order maximum damping force F1, the first-order damping coefficient C1, the second-order maximum damping force F2, the second-order maximum damping coefficient C2 and the damping index alpha of the viscous damper with the variable damping coefficient; judging whether the limit displacement X, the first-order maximum damping force F1, the first-order damping coefficient C1, the second-order maximum damping force F2, the second-order maximum damping coefficient C2 and the damping index alpha meet the design standard; if all the six parameters meet the design standard, the viscous damper with the variable damping coefficient is determined to be qualified; otherwise, the viscous damper with the variable damping coefficient is determined to be unqualified. The application can more truly and effectively detect the anti-seismic performance of the viscous damper with the variable damping coefficient, and improve the accuracy and reliability of the test results.

Description

Technical Field

[0001] This invention relates to the field of damper technology, and in particular to a performance testing method for a viscous damper with a variable damping coefficient. Background Technology

[0002] Earthquakes cause severe damage to human beings, and energy-dissipating damping technology has been widely used and researched in earthquake-resistant engineering. Viscous dampers, due to their advantages such as good damping effect, simple structure, and long service life, are increasingly widely used in the field of structural vibration reduction.

[0003] Before a viscous damper is used in engineering applications, performance testing is essential to determine whether it meets engineering requirements. A viscous damper is a velocity-dependent damper; its dynamic characteristics are closely related to the loading speed. Different loading speeds will result in different maximum damping forces, damping coefficients, and damping exponents. Therefore, the scientific nature of the test methods and the accuracy of data processing have a significant impact on the test results.

[0004] Existing testing methods for viscous dampers generally follow the test methods in the industry standard JG / T209-2012 "Building Energy Dissipation Dampers," testing the maximum damping force, damping coefficient, and damping index of the damper. The applied frequency and displacement magnitude depend on the seismic requirements of the structure. The damping coefficient of traditional viscous dampers is generally constant, thus existing testing methods can be used. However, in some special engineering projects, it is desirable for the damping coefficient to be controllable and adjustable. In viscous dampers with variable damping coefficients, the damping coefficient changes with the displacement and is not a fixed value.

[0005] Therefore, existing testing methods are no longer suitable for testing the performance indicators of viscous dampers with variable damping coefficients, leading to inaccurate test results and misjudgments. It is unacceptable to either classify a qualified viscous damper as unqualified or an unqualified viscous damper as qualified during testing. Therefore, a new testing method suitable for viscous dampers with variable damping coefficients is needed. Summary of the Invention

[0006] The technical problem this invention aims to solve is to address the inaccuracy of test results when existing damper performance testing methods are used to test viscous dampers with variable damping coefficients. This invention provides a performance testing method for viscous dampers with variable damping coefficients, which improves the accuracy of test results.

[0007] The technical solution adopted by this invention to solve its technical problem is: a performance testing method for a viscous damper with a variable damping coefficient, comprising the following steps:

[0008] S1. Calculate the fundamental frequency of a viscous damper with variable damping coefficient;

[0009] S2. Obtain the ultimate displacement X of the viscous damper with variable damping coefficient;

[0010] S3. Obtain the first-order maximum damping force F1 of the viscous damper with variable damping coefficient;

[0011] S4. Obtain the first-order damping coefficient C1 of the viscous damper with variable damping coefficient;

[0012] S5. Obtain the second-order maximum damping force F2 of the viscous damper with variable damping coefficient;

[0013] S6. Obtain the second-order maximum damping coefficient C2 and damping exponent α of the viscous damper with variable damping coefficient;

[0014] S7. Determine whether the ultimate displacement X, first-order maximum damping force F1, first-order damping coefficient C1, second-order maximum damping force F2, second-order maximum damping coefficient C2, and damping index α meet the design standards; if the ultimate displacement X, first-order maximum damping force F1, first-order damping coefficient C1, second-order maximum damping force F2, second-order damping coefficient C2, and damping index α all meet the design standards, then the viscous damper with variable damping coefficient is deemed qualified; otherwise, it is deemed unqualified.

[0015] Furthermore, in step S1, the calculation process for the fundamental frequency includes:

[0016] The design velocity V0 is calculated based on the design parameters of the viscous damper with variable damping coefficient.

[0017] Based on the design velocity V0 and the first-order design displacement u 10 The first-order frequency f1 of the viscous damper with variable damping coefficient is calculated and taken as the fundamental frequency.

[0018] The design parameters include: the first-order maximum damping force design value F0, the first-order damping coefficient design value C0, and the damping exponent design value α0, wherein... ,

[0019] The formula for calculating the first-order frequency f1 is: .

[0020] Furthermore, in step S2, the process of obtaining the ultimate displacement X includes:

[0021] The static loading test method is adopted. The loading system of the test machine is controlled to make the viscous damper move slowly and uniformly, and the limit value of the expansion and contraction of the viscous damper is recorded. The limit value is the limit displacement X.

[0022] Furthermore, in step S3, the process of obtaining the first-order maximum damping force F1 includes:

[0023] A sinusoidal excitation method is used to apply a frequency of f1 and a displacement amplitude of u to a viscous damper with a variable damping coefficient. 10 The sine wave is repeated five times.

[0024] The displacement loading expression is:

[0025] (1)

[0026] (2)

[0027] Among them, u 10 The first-order design displacement is given, and f1 is the test fundamental frequency. The frequency is angular frequency, and t represents time;

[0028] The loading system of the testing machine is controlled according to formula (1). Input frequencies f(n) of f(1)=0.1f1, f(2)=0.2f1, f(3)=0.5f1, f(4)=0.7f1, f(5)=f1 and f(6)=1.2f1 are applied to the viscous damper with variable damping coefficient, respectively. n=1~6, which represent the frequencies corresponding to the 6 working conditions. One input frequency represents one working condition, and the displacement amplitude u is input under each working condition. 10 Record and plot the first-order damping force-displacement hysteresis curves under different working conditions;

[0029] Obtain the maximum value F in each first-order damping force-displacement hysteresis curve. 11 and minimum value F 12 Let F1 and F2 represent the damping force values ​​in the tension and compression directions, respectively. The first-order maximum damping force F1 = (|F1||F2||F2||F3||F4||F5||F6||F7 ... 11 |+|F 12 |) / 2.

[0030] Furthermore, in step S4, the process of obtaining the first-order damping coefficient C1 includes:

[0031] Taking the derivative of formula (1), we get:

[0032] (3)

[0033] (4)

[0034] Where f(n) represents the input frequency, and n is a positive integer; substituting formula (4) into formula (3), we obtain the first-order velocity V1(t) under each working condition:

[0035] (5)

[0036] This leads to the first-order maximum speed V under various operating conditions. 1max :

[0037] (6)

[0038] Substituting the frequency f(n) under different operating conditions into formula (6), the first-order maximum velocity V under different operating conditions can be calculated. 1max ;

[0039] Using nonlinear regression equations to determine the first-order maximum speed V under different working conditions 1max By performing a nonlinear fit with the first-order maximum damping force F1, the first-order maximum damping force F1 and the first-order maximum velocity V are obtained. 1max Relationship curve Where y1 represents the first-order maximum damping force, x1 represents the first-order maximum velocity, and k1 and b1 are both constants. The constant k1 is the first-order damping coefficient C1.

[0040] Furthermore, in step S5, the process of obtaining the second-order maximum damping force F2 includes:

[0041] A sinusoidal excitation method is used to apply a frequency of f1 and a displacement amplitude of u to a viscous damper with a variable damping coefficient. 20 The sine wave cycles through five periods.

[0042] The displacement loading expression is:

[0043] (7)

[0044] Among them, u 20 For second-order design displacement, Let t be the angular frequency and t represent time.

[0045] According to the loading system of the sinusoidal wave controlled testing machine according to formula (7), the input frequencies f(n) of f(1)=0.1f1, f(2)=0.2f1, f(3)=0.5f1, f(4)=0.7f1, f(5)=f1 and f(6)=1.2f1 are applied to the viscous damper with variable damping coefficient, respectively. n=1~6, representing the frequencies corresponding to the 6 working conditions. One input frequency represents one working condition, and the displacement amplitude u is input under each working condition. 20 Record and plot the second-order damping force-displacement hysteresis curves under different working conditions;

[0046] Taking the derivative of formula (7), we get:

[0047] (8)

[0048] Substituting formula (4) into formula (8), we obtain the second-order velocity V2(t) under various working conditions:

[0049] (9)

[0050] Differentiating formula (9), we get

[0051] (10)

[0052] make We obtain the stationary points t1, t2, t3, and t4. Differentiating equation (10), we obtain...

[0053] (11)

[0054] Substituting the stationary points t1, t2, t3, and t4 into formula (11), and based on the extreme value judgment condition, the minimum value F in each second-order damping force-displacement hysteresis curve is obtained. 21 F 22 and the maximum value F 23 F 24 Let F and F represent the two maximum damping force values ​​existing in the tension and compression directions, respectively, to obtain the second-order maximum damping force F2=(|F 21 |+|F 22 |+|F 23 |+|F 24 |) / 4.

[0055] Furthermore, in step S6, the process of obtaining the second-order maximum damping coefficient C2 and the damping exponent α includes:

[0056] Substituting the stationary points t1, t2, t3, and t4 and the input frequency f(n) into formula (9), we obtain the speed V under different operating conditions. 21 V 22 V 23 and V 24 Then calculate the second-order maximum velocity V under different working conditions. 2max :

[0057] V 2max =(|V 21 |+|V 22 |+|V 23 |+|V 24 |) / 4 (12)

[0058] Using nonlinear regression equations to determine the second-order maximum speed V under different working conditions 2max By performing nonlinear fitting with the second-order maximum damping force F2, the second-order maximum damping force F2 and the second-order maximum velocity V are obtained. 2max Relationship curve Where y2 represents the second-order maximum damping force, x2 represents the second-order maximum velocity, k2 and b2 are both constants, the constant k2 is the second-order maximum damping coefficient C2, and the constant b2 is the damping exponent α.

[0059] Further, in step S7, determining whether the ultimate displacement X, the first-order maximum damping force F1, the first-order damping coefficient C1, the second-order maximum damping force F2, the second-order maximum damping coefficient C2, and the damping exponent α meet the design standards includes:

[0060] When the design displacement is less than 100 mm, if the test value of the limit displacement X is at least 150% of the design displacement, then it meets the design standard.

[0061] When the design displacement is ≥100mm, if the test value of the ultimate displacement X is at least 120% of the design displacement, then it meets the design standard.

[0062] If the test value of the first-order maximum damping force F1 is within ±15% of the design value of the first-order maximum damping force F0, then it meets the design standard.

[0063] If the test value of the first-order damping coefficient C1 is within ±15% of the design value of the first-order damping coefficient C0, then it meets the design standard.

[0064] If the test value of the second-order maximum damping force F2 is within ±15% of the design value of the second-order maximum damping force, then it meets the design standard.

[0065] If the test value of the second-order maximum damping coefficient C2 is within ±15% of the design value of the second-order damping coefficient, then it meets the design standard.

[0066] If the test value of the damping index α is within ±15% of the design value α0 of the damping index, then it meets the design standard.

[0067] Furthermore, the second-order maximum damping coefficient C2 is greater than the first-order damping coefficient C1, and the second-order maximum damping force F2 is greater than the first-order maximum damping force F1.

[0068] The beneficial effect of this invention is that by testing the performance parameters F1 and C1 in the small displacement stage and the performance parameters F2, C2, and α in the large displacement stage, the seismic performance of the viscous damper with variable damping coefficient can be detected more realistically and effectively, thereby improving the accuracy and reliability of the test results. Attached Figure Description

[0069] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0070] Figure 1 This is a flowchart of the performance testing method for the viscous damper with variable damping coefficient of the present invention.

[0071] Figure 2 This is a graph showing the relationship between the damping coefficient and displacement of the present invention.

[0072] Figure 3 This is a graph showing the relationship between the displacement and time of the damper of this invention.

[0073] Figure 4 This is the hysteresis curve of the first-order maximum damping force versus displacement of the present invention.

[0074] Figure 5 This is the fitting curve of the first-order maximum damping force versus velocity of the present invention.

[0075] Figure 6 This is a graph of the damping force versus time in this invention.

[0076] Figure 7 This is the hysteresis curve of the second-order maximum damping force versus displacement of the present invention.

[0077] Figure 8 This is the fitting curve of the second-order maximum damping force versus velocity in this invention. Detailed Implementation

[0078] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0079] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0080] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0081] like Figure 1 As shown, the performance testing method for a viscous damper with a variable damping coefficient according to the present invention includes the following steps: S1, calculating the fundamental frequency of the viscous damper with a variable damping coefficient; S2, obtaining the ultimate displacement X of the viscous damper with a variable damping coefficient; S3, obtaining the first-order maximum damping force F1 of the viscous damper with a variable damping coefficient; S4, obtaining the first-order damping coefficient C1 of the viscous damper with a variable damping coefficient; S5, obtaining the second-order maximum damping force F2 of the viscous damper with a variable damping coefficient; S6, obtaining the second-order maximum damping coefficient C2 and the damping index α of the viscous damper with a variable damping coefficient. S7. Determine whether the ultimate displacement X, first-order maximum damping force F1, first-order damping coefficient C1, second-order maximum damping force F2, second-order maximum damping coefficient C2, and damping exponent α meet the design standards. If the ultimate displacement X, first-order maximum damping force F1, first-order damping coefficient C1, second-order maximum damping force F2, second-order damping coefficient C2, and damping exponent α all meet the design standards, then the viscous damper with variable damping coefficient is deemed qualified; otherwise, it is deemed unqualified.

[0082] Variable damping coefficient viscous dampers are designed to meet the specific needs of different displacement stages in engineering projects by setting corresponding damper parameter values. In some projects, it is desirable for the damper to provide a small damping force when the structural response displacement is small, while the damping force generated by the damper needs to increase immediately when the structural response displacement exceeds a certain value. For example... Figure 2 As shown, within the displacement range of 0-40mm (small displacement stage), the damping coefficient remains essentially constant. When the displacement exceeds 40mm (large displacement stage), the damping coefficient suddenly increases and continues to increase with the displacement. This method divides the test into two stages: the first-order maximum damping force F1 corresponds to the case of small displacement, and the second-order maximum damping force F2 corresponds to the case of large displacement. The performance parameters F1, C1 and F2, C2, α in the two stages represent the seismic resistance effect under small earthquakes (small displacement) and large earthquakes (large displacement), respectively, which can more accurately reflect the performance of viscous dampers with variable damping coefficients.

[0083] Specifically, in step S1, the fundamental frequency calculation process includes: calculating the design velocity V0 based on the design parameters of the viscous damper with variable damping coefficient; and calculating the design velocity V0 and the first-order design displacement u. 10 The first-order frequency f1 of the viscous damper with variable damping coefficient is calculated and taken as the fundamental frequency. Design parameters include: the design value of the first-order maximum damping force F0, the design value of the first-order damping coefficient C0, and the design value of the damping exponent α0. The formula for calculating the first-order frequency f1 is: In other words, the design parameters are performance parameters that have been determined during the design phase. Based on these parameters, the magnitude of the first-order frequency f1 can be calculated, and f1 can be set as the fundamental frequency of the experiment.

[0084] Specifically, in step S2, the process of obtaining the ultimate displacement X includes: using a static loading test method, controlling the loading system of the testing machine to make the viscous damper move slowly and uniformly, and recording the limit value of the viscous damper's expansion and contraction motion; the limit value is the ultimate displacement X. When the design displacement is <100mm, if the test value of the ultimate displacement X is at least 150% of the design displacement, it meets the design standard; when the design displacement is ≥100mm, if the test value of the ultimate displacement X is at least 120% of the design displacement, it meets the design standard.

[0085] Specifically, in step S3, the process of obtaining the first-order maximum damping force F1 includes: using a sinusoidal excitation method, applying a frequency of f1 and a displacement amplitude of u to a viscous damper with a variable damping coefficient. 10 A sine wave is applied five times; the displacement loading expression is:

[0086] (1)

[0087] (2)

[0088] Among them, u 10 The first-order design displacement is given, and f1 is the test fundamental frequency. The frequency is angular frequency, and t represents time;

[0089] The loading system of the testing machine is controlled according to formula (1). Input frequencies f(n) of f(1)=0.1f1, f(2)=0.2f1, f(3)=0.5f1, f(4)=0.7f1, f(5)=f1 and f(6)=1.2f1 are applied to the viscous damper with variable damping coefficient, respectively. n=1~6, which represent the frequencies corresponding to the six working conditions. One input frequency represents one working condition, and the displacement amplitude u is input under each working condition. 10 Record and plot the first-order damping force-displacement hysteresis curves under different working conditions; obtain the maximum value F in each first-order damping force-displacement hysteresis curve.11 and minimum value F 12 Let F1 and F2 represent the damping force values ​​in the tension and compression directions, respectively. The first-order maximum damping force F1 = (|F1||F2||F2||F3||F4||F5||F6||F7 ... 11 |+|F 12 |) / 2.

[0090] For example, a displacement signal varying according to formula (1) can be sent to the testing machine via a computer control platform (e.g., ...). Figure 3 As shown), the testing machine can control the loading of the damper. Displacement sensors and tension / compression sensors can record the displacement and first-order damping force of the damper under different operating conditions over time, and plot the first-order damping force-displacement hysteresis curve. A first-order damping force-displacement hysteresis curve can be obtained for each operating condition (e.g., ...). Figure 4 As shown), from Figure 4 As can be seen from this, the first-order damping force-displacement hysteresis curve has a maximum value F. 11 and minimum value F 12 The first-order maximum damping force F1 is (|F 11 |+|F 12 |) / 2. During the test, five cycles were performed under each working condition. The first-order maximum damping force F1 obtained from the hysteresis curve in the third cycle was taken as the test value. If the test value of the first-order maximum damping force F1 is within ±15% of the design value F0 of the first-order maximum damping force, then it meets the design standard.

[0091] Specifically, in step S4, the process of obtaining the first-order damping coefficient C1 includes: taking the derivative of formula (1) to obtain:

[0092] (3)

[0093] (4)

[0094] Where f(n) represents the input frequency, and n is a positive integer; substituting formula (4) into formula (3), we obtain the first-order velocity V1(t) under each working condition:

[0095] (5)

[0096] This leads to the first-order maximum speed V under various operating conditions. 1max :

[0097] (6)

[0098] Substituting the frequency f(n) under different operating conditions into formula (6), the first-order maximum velocity V under different operating conditions can be calculated. 1max The first-order maximum speed V under different working conditions is obtained by using a nonlinear regression equation. 1maxBy performing a nonlinear fit with the first-order maximum damping force F1, the first-order maximum damping force F1 and the first-order maximum velocity V are obtained. 1max Relationship curve Where y1 represents the first-order maximum damping force, x1 represents the first-order maximum velocity, and k1 and b1 are constants. The constant k1 is the first-order damping coefficient C1. If the measured value of the first-order damping coefficient C1 is within ±15% of the design value C0 of the first-order damping coefficient, then it meets the design standard.

[0099] For example Figure 5 As shown, the first-order maximum damping force F1 and the first-order maximum velocity V 1max The fitted relationship curve between them is goodness of fit R 2 The goodness of fit is 0.998, and the R-value is 0.998. 2 The closer the value of R is to 1, the better the curve fit. Generally, when R... 2 A value greater than 0.9 is considered a valid fit. The goodness of fit Rfit 2 The calculation formula is as follows: , , , .

[0100] Specifically, in step S5, the process of obtaining the second-order maximum damping force F2 includes: using a sinusoidal excitation method, applying a frequency of f1 and a displacement amplitude of u to a viscous damper with a variable damping coefficient. 20 A sine wave is applied five times; the displacement loading expression is:

[0101] (7)

[0102] Among them, u 20 For second-order design displacement, Let t be the angular frequency and t represent time. According to the loading system of the sine wave control test machine according to formula (7), the input frequencies f(n) of f(1)=0.1f1, f(2)=0.2f1, f(3)=0.5f1, f(4)=0.7f1, f(5)=f1 and f(6)=1.2f1 are applied to the viscous damper with variable damping coefficient, respectively. n=1~6, which represent the frequencies corresponding to the 6 working conditions. One input frequency represents one working condition, and the displacement amplitude u is input under each working condition. 20 The second-order damping force-displacement hysteresis curves under different working conditions were recorded and plotted. Due to the special nature of the test equipment, the applied displacement signal must be increased from zero. Therefore, during the second-order test, the displacement includes the displacement changes from the first-order test.

[0103] Taking the derivative of formula (7), we get:

[0104] (8)

[0105] Substituting formula (4) into formula (8), we obtain the second-order velocity V2(t) under various working conditions:

[0106] (9)

[0107] Differentiating formula (9), we get

[0108] (10)

[0109] make We obtain the stationary points t1, t2, t3, and t4. Differentiating equation (10), we obtain...

[0110] (11)

[0111] Substituting the stationary points t1, t2, t3, and t4 into formula (11), and based on the extreme value judgment condition, the minimum value F in each second-order damping force-displacement hysteresis curve is obtained. 21 F 22 and the maximum value F 23 F 24 Let F and F represent the two maximum damping force values ​​existing in the tension and compression directions, respectively, to obtain the second-order maximum damping force F2=(|F 21 |+|F 22 |+|F 23 |+|F 24 |) / 4. Since the second-order damping force-displacement hysteresis curve has two maximum points and two minimum points within one cycle, it is not easy to obtain the second-order maximum damping force directly from the second-order damping force-displacement hysteresis curve. It needs to be calculated using a formula.

[0112] Please refer to Figure 6 and Figure 7 For example, substituting the stationary points t1, t2, t3, and t4 into formula (11) respectively, we get: , , , Therefore, V2(t) reaches a minimum at t1 and t2, and a maximum at t3 and t4. Since velocity is positively correlated with damping force, the minimum value F of the second-order damping force can be obtained at t1 and t2. 21 F 22 The maximum value of the second-order damping force F can be obtained at t3 and t4. 23 F 24During the test, five cycles were performed under each working condition. The second-order maximum damping force F2 obtained from the hysteresis curve in the third cycle was taken as the test value. If the test value of the second-order maximum damping force F2 is within ±15% of the design value of the second-order maximum damping force, it meets the design standard.

[0113] Specifically, in step S6, the process of obtaining the second-order maximum damping coefficient C2 and the damping exponent α includes: substituting the stagnation points t1, t2, t3, and t4 and the input frequency f(n) into formula (9) respectively to obtain the velocity V under different working conditions. 21 V 22 V 23 and V 24 Then calculate the second-order maximum velocity V under different working conditions. 2max :

[0114] V 2max =(|V 21 |+|V 22 |+|V 23 |+|V 24 |) / 4 (11)

[0115] Using nonlinear regression equations to determine the second-order maximum speed V under different working conditions 2max By performing nonlinear fitting with the second-order maximum damping force F2, the second-order maximum damping force F2 and the second-order maximum velocity V are obtained. 2max Relationship curve Where y2 represents the second-order maximum damping force, x2 represents the second-order maximum velocity, k2 and b2 are both constants, the constant k2 is the second-order maximum damping coefficient C2, and the constant b2 is the damping exponent α.

[0116] For example Figure 8 As shown, the second-order maximum damping force F2 and the second-order maximum velocity V 2max The relationship curve is R 2 =0.999, that is, the second-order maximum damping coefficient C2 is 655.8, and the damping exponent α is 0.388. If the measured value of the second-order maximum damping coefficient C2 is within ±15% of the design value of the second-order damping coefficient, it meets the design standard; if the measured value of the damping exponent α is within ±15% of the design value of the damping exponent α0, it meets the design standard.

[0117] When a viscous damper experiences small displacements, its damping coefficient C1 is relatively small. However, as the displacement increases, the damping coefficient C2 increases significantly. A larger damping coefficient results in a larger damping force. Therefore, under small earthquakes or light wind loads, the damper's structural response (e.g., displacement) is small, and the damping force is also small. Under large earthquakes or strong wind loads, the damper's structural response (e.g., displacement) is large, and the damping force increases immediately. Therefore, the test needs to be conducted in two stages: the first stage tests the damper's effectiveness against small earthquakes, and the second stage tests its effectiveness against large earthquakes. Since the damping coefficient in the second stage increases with increasing displacement, only the second-order maximum damping coefficient was tested to ensure it was within the standard range. The second-order maximum damping coefficient C2 is greater than the first-order damping coefficient C1, and the second-order maximum damping force F2 is greater than the first-order maximum damping force F1.

[0118] In summary, by testing the performance parameters F1 and C1 during the small displacement stage and the performance parameters F2, C2, and α during the large displacement stage, this invention can more realistically and effectively detect the seismic performance of viscous dampers with variable damping coefficients, thereby improving the accuracy and reliability of the test results.

[0119] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined by the scope of the claims.

Claims

1. A performance testing method for a viscous damper with a variable damping coefficient, characterized in that, Includes the following steps: S1. Calculate the fundamental frequency of a viscous damper with variable damping coefficient; The calculation process for the fundamental frequency includes: The design velocity V0 is calculated based on the design parameters of the viscous damper with variable damping coefficient. Based on the design velocity V0 and the first-order design displacement u 10 The first-order frequency f1 of the viscous damper with variable damping coefficient is calculated and taken as the fundamental frequency. The design parameters include: the design value of the first-order maximum damping force F0, the design value of the first-order damping coefficient C0, and the design value of the damping exponent α0, wherein... , The formula for calculating the first-order frequency f1 is: ; S2. Obtain the ultimate displacement X of the viscous damper with variable damping coefficient; S3. Obtain the first-order maximum damping force F1 of the viscous damper with variable damping coefficient; The process of obtaining the first-order maximum damping force F1 includes: A sinusoidal excitation method is used to apply a frequency of f1 and a displacement amplitude of u to a viscous damper with a variable damping coefficient. 10 A sine wave, repeated five times. The displacement loading expression is: （1） （2） Among them, u 10 The first-order design displacement is given, and f1 is the test fundamental frequency. The frequency is angular frequency, and t represents time; The loading system of the testing machine is controlled according to formula (1). Input frequencies f(n) of f(1)=0.1f1, f(2)=0.2f1, f(3)=0.5f1, f(4)=0.7f1, f(5)=f1 and f(6)=1.2f1 are applied to the viscous damper with variable damping coefficient, respectively. n=1~6, which represent the frequencies corresponding to the 6 working conditions. One input frequency represents one working condition, and the displacement amplitude u10 is input under each working condition. The first-order damping force-displacement hysteresis curves under different working conditions are recorded and plotted. Obtain the maximum value F in each first-order damping force-displacement hysteresis curve. 11 and minimum value F 12 Let F1 and F2 represent the damping force values ​​in the tension and compression directions, respectively. The first-order maximum damping force F1 = (|F1||F2||F2||F3||F4||F5||F6||F7 ... 11 |+|F 12 |) / 2; S4. Obtain the first-order damping coefficient C1 of the viscous damper with variable damping coefficient; The process of obtaining the first-order damping coefficient C1 includes: Taking the derivative of formula (1), we get: （3） （4） Where f(n) represents the input frequency, and n is a positive integer; substituting formula (4) into formula (3), we obtain the first-order velocity V1(t) under each working condition: （5） This leads to the first-order maximum speed V under various operating conditions. 1max : （6） Substituting the frequency f(n) under different operating conditions into formula (6), the first-order maximum velocity V under different operating conditions can be calculated. 1max ; Using nonlinear regression equations to determine the first-order maximum speed V under different working conditions 1max By performing a nonlinear fit with the first-order maximum damping force F1, the first-order maximum damping force F1 and the first-order maximum velocity V are obtained. 1max Relationship curve Where y1 represents the first-order maximum damping force, x1 represents the first-order maximum velocity, and k1 and b1 are both constants. The constant k1 is the first-order damping coefficient C1. S5. Obtain the second-order maximum damping force F2 of the viscous damper with variable damping coefficient; The process of obtaining the second-order maximum damping force F2 includes: A sinusoidal excitation method is used to apply a frequency of f1 and a displacement amplitude of u to a viscous damper with a variable damping coefficient. 20 The sine wave cycles through five periods. The displacement loading expression is: （7） Among them, u 20 For second-order design displacement, Let t be the angular frequency and t represent time. According to the loading system of the sinusoidal wave controlled testing machine according to formula (7), the input frequencies f(n) of f(1)=0.1f1, f(2)=0.2f1, f(3)=0.5f1, f(4)=0.7f1, f(5)=f1 and f(6)=1.2f1 are applied to the viscous damper with variable damping coefficient, respectively. n=1~6, which represent the frequencies corresponding to the 6 working conditions. One input frequency represents one working condition, and the displacement amplitude u is input under each working condition. 20 Record and plot the second-order damping force-displacement hysteresis curves under different working conditions; Taking the derivative of formula (7), we get: （8） Substituting formula (4) into formula (8), we obtain the second-order velocity V2(t) under various working conditions: （9） Differentiating formula (9), we get （10） make We obtain the stationary points t1, t2, t3, and t4. Differentiating equation (10), we obtain... （11） Substituting the stationary points t1, t2, t3, and t4 into formula (11), and based on the extreme value judgment condition, the minimum value F in each second-order damping force-displacement hysteresis curve is obtained. 21 F 22 and the maximum value F 23 F 24 Let F and F represent the two maximum damping force values ​​existing in the tension and compression directions, respectively, to obtain the second-order maximum damping force F2=(|F 21 |+|F 22 |+|F 23 |+|F 24 |) / 4; S6. Obtain the second-order maximum damping coefficient C2 and damping exponent α of the viscous damper with variable damping coefficient; The process of obtaining the second-order maximum damping coefficient C2 and the damping exponent α includes: Substituting the stationary points t1, t2, t3, and t4 and the input frequency f(n) into formula (9), we obtain the speed V under different operating conditions. 21 V 22 V 23 and V 24 Then calculate the second-order maximum velocity V under different working conditions. 2max : V 2max =(|V 21 |+|V 22 |+|V 23 |+|V 24 |) / 4(12) Using nonlinear regression equations to determine the second-order maximum speed V under different working conditions 2max By performing nonlinear fitting with the second-order maximum damping force F2, the second-order maximum damping force F2 and the second-order maximum velocity V are obtained. 2max Relationship curve Where y2 represents the second-order maximum damping force, x2 represents the second-order maximum velocity, k2 and b2 are both constants, the constant k2 is the second-order maximum damping coefficient C2, and the constant b2 is the damping exponent α; S7. Determine whether the ultimate displacement X, first-order maximum damping force F1, first-order damping coefficient C1, second-order maximum damping force F2, second-order maximum damping coefficient C2, and damping index α meet the design standards; if the ultimate displacement X, first-order maximum damping force F1, first-order damping coefficient C1, second-order maximum damping force F2, second-order damping coefficient C2, and damping index α all meet the design standards, then the viscous damper with variable damping coefficient is deemed qualified; otherwise, it is deemed unqualified.

2. The performance testing method for a viscous damper with a variable damping coefficient as described in claim 1, characterized in that, In step S2, the process of obtaining the ultimate displacement X includes: The static loading test method is adopted. The loading system of the test machine is controlled to make the viscous damper move slowly and uniformly, and the limit value of the expansion and contraction of the viscous damper is recorded. The limit value is the limit displacement X.

3. The performance testing method for a viscous damper with a variable damping coefficient as described in claim 2, characterized in that, In step S7, determining whether the ultimate displacement X, first-order maximum damping force F1, first-order damping coefficient C1, second-order maximum damping force F2, second-order maximum damping coefficient C2, and damping exponent α meet the design standards includes: When the design displacement is less than 100 mm, if the test value of the limit displacement X is at least 150% of the design displacement, then it meets the design standard. When the design displacement is ≥100mm, if the test value of the ultimate displacement X is at least 120% of the design displacement, then it meets the design standard. If the test value of the first-order maximum damping force F1 is within ±15% of the design value of the first-order maximum damping force F0, then it meets the design standard. If the test value of the first-order damping coefficient C1 is within ±15% of the design value of the first-order damping coefficient C0, then it meets the design standard. If the test value of the second-order maximum damping force F2 is within ±15% of the design value of the second-order maximum damping force, then it meets the design standard. If the test value of the second-order maximum damping coefficient C2 is within ±15% of the design value of the second-order damping coefficient, then it meets the design standard. If the test value of the damping index α is within ±15% of the design value α0 of the damping index, then it meets the design standard.

4. The performance testing method for a viscous damper with a variable damping coefficient as described in claim 1, characterized in that, The second-order maximum damping coefficient C2 is greater than the first-order damping coefficient C1, and the second-order maximum damping force F2 is greater than the first-order maximum damping force F1.

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