Fatigue test device and test method for prefabricated assembled rail top air duct components

Abstract

The present invention discloses a fatigue testing device and testing method for prefabricated rail-top air duct components. The prefabricated rail-top air duct components are provided with embedded grooves, and the embedded grooves are provided with T-bolts for fixing the components. The fatigue testing device includes a test bench, a load test block, a static load test rod, a dynamic load test rod, and a downward pressure fixing structure for fixing the air duct components. The prefabricated rail-top air duct components are placed on the test bench and fixed by the downward pressure fixing structure. The load test block is provided on the prefabricated rail-top air duct components corresponding to the embedded grooves and T-bolts. The load test block is provided with an inclined surface. The static load test rod is provided corresponding to the center of the load test block, and the dynamic load test rod is provided corresponding to the inclined surface of the load test block. The prefabricated rail-top air duct components can be subjected to static and dynamic load fatigue tests, simulating the fatigue damage effects caused by long-term high-speed trains under positive and negative wind pressures, and can effectively verify the reliability of the rail-top air duct connection.

Description

Technical Field

[0001] The present invention relates to the technical field of rail top air ducts, and in particular to a fatigue testing device and a testing method for prefabricated and assembled rail top air duct components. Background Art

[0002] The track top duct, also known as the exhaust duct on top of the train, is an important internal structural component of the subway station ventilation system. It is hung at the intersection of the station center plate and the structural side wall. Due to the special nature of its location, it is generally not cast at the same time as the main body of the station. Especially in stations where shield construction needs to pass through, the track top duct must be cast later. The structural design of the track top duct of the subway station is based on the 100-year design. At present, the domestic track top duct basically adopts secondary cast-in-place concrete, and the track top duct anchor steel bars and duct casting holes are reserved at the bottom of the center plate. This means that the civil construction of the station needs to enter the site twice, set up scaffolding and formwork, and occupy the time and space for the later track laying, electromechanical installation and decoration. In addition, the space for the post-cast track top duct concrete is narrow, and it is difficult to pump concrete, vibrate and smooth the surface, making it difficult to guarantee the construction quality.

[0003] Since the cross-sectional dimensions of the rail-top air duct structure are relatively stable and it is located in the straight section of the station, the use of prefabricated rail-top air ducts can effectively solve the above-mentioned problems. However, most prefabricated types use mechanical connections, that is, embedded grooves are provided on the prefabricated rail-top air duct components, which are connected by T-bolts. Under the repeated action of positive and negative wind pressures at high speeds during long-term train operation, the components are prone to fatigue damage, posing a safety hazard to train operation. However, there is currently no device or method suitable for fatigue testing of prefabricated rail-top air duct components, and the reliability of the rail-top air duct connection cannot be effectively verified. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the present invention provides a fatigue testing device and testing method for prefabricated and assembled rail-top air duct components, so as to achieve the purpose of effectively verifying the reliability of the rail-top air duct connection.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A fatigue testing device for a prefabricated and assembled rail-top air duct component, wherein the prefabricated and assembled rail-top air duct component is provided with an embedded groove, and the embedded groove is provided with a T-bolt for fixing the component. The fatigue testing device comprises a test bench, a load test block, a static load test rod, a dynamic load test rod and a downward-pressing fixing structure for fixing the air duct component; the prefabricated and assembled rail-top air duct component is arranged on the test bench and fixed by the downward-pressing fixing structure, the load test block is arranged on the prefabricated and assembled rail-top air duct component corresponding to the embedded groove and the T-bolt, the load test block is provided with an inclined surface, the static load test rod is arranged corresponding to the center of the load test block, and the dynamic load test rod is arranged corresponding to the inclined surface of the load test block.

[0007] Further:

[0008] A loader is provided above the test bench, and a loading rod is provided below the loader.

[0009] The downward pressing and fixing structure includes a pressing block, a pressing plate and a group of columns. The lower ends of the columns are fixed on the test bench, the pressing plate is arranged between two columns, and the pressing block is arranged on one column.

[0010] It also includes a loading tool for static load pressurization, which includes a pressure sensor, a static load loading rod, and a tool frame for being arranged on the air duct component. The static load loading rod passes through the pressure sensor and is arranged on the tool frame, and the lower end of the static load loading rod is arranged corresponding to the top end of the T-bolt.

[0011] The prefabricated and assembled rail-top air duct component is placed on a test bench via a test pad.

[0012] The load test block is arranged on the prefabricated assembled rail top air duct component through a groove fixing pad.

[0013] The tooling frame comprises a pair of vertical plates and a horizontal plate arranged between the tops of the pair of vertical plates, and the pressure sensor is arranged above the horizontal plate.

[0014] A fatigue test method for a prefabricated and assembled rail-top air duct component comprises the following steps:

[0015] S1. Under static conditions, a constant static load of 4kN is applied to the embedded channel in the vertical direction using a screw and a pressure sensor;

[0016] S2. After applying the static load, a dynamic load is applied in the spatial vector direction of the dynamic load resultant force. The force parameters of the dynamic load are: force range 0~7.88KN, frequency: 3Hz, number of times: 2 million times, and the force direction is the spatial resultant force direction of the dynamic three-axis load;

[0017] S3. Observe whether the embedded grooves or T-bolts are damaged during the 2 million tests.

[0018] in,

[0019] The loading direction of the dynamic load has spatial angles of 82°, 60°, and 31° with the X-axis, Y-axis, and Z-axis, respectively, and the loading waveform of the dynamic load is a sine wave.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] The fatigue test device and test method for prefabricated and assembled rail-top air duct components are rationally designed and can perform static and dynamic load fatigue tests on prefabricated and assembled rail-top air duct components, simulating the fatigue damage effects caused by long-term high-speed positive and negative wind pressures on trains, and can effectively verify the reliability of the rail-top air duct connection. In addition, the device has a simple structure and the fatigue test operation is easy. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The following is a brief description of the contents and symbols in the drawings of this specification:

[0023] Figure 1 It is a schematic diagram of the structure of the device of the present invention.

[0024] Figure 2 This is a schematic diagram of the loading tooling of the present invention.

[0025] Figure 3 It is a force diagram of the component of the present invention.

[0026] In the picture:

[0027] 1. Test bench, 2. Test pad, 3. Prefabricated rail-top air duct component, 301. Embedded slot, 4. Pressure plate, 5. Pressure block, 6. Slot fixing pad, 7. Load test block, 8. Static load test rod, 9. Dynamic load test rod, 10. Tooling frame, 11. Pressure sensor, 12. Static load loading rod. DETAILED DESCRIPTION

[0028] The specific implementation of the present invention will be further explained in detail below through description of embodiments with reference to the accompanying drawings.

[0029] like Figure 1 and Figure 2 As shown, the fatigue test device for the prefabricated and assembled rail-top air duct component includes a test bench 1, a load test block 7, a static load test rod 8, a dynamic load test rod 9, a loader, and a downward pressing fixing structure for fixing the air duct component.

[0030] The prefabricated and assembled rail top air duct component 3 is provided with an embedded groove 301, in which a T-bolt for fixing the component is provided. The embedded groove is a Halfen groove, in which the lower end of the T-bolt is located. The prefabricated and assembled rail top air duct component is fixed by a group of T-bolts.

[0031] The prefabricated assembled rail top air duct component is placed on the test bench and fixed by a downward pressing fixing structure. The load test block is provided with an inclined surface on the prefabricated assembled rail top air duct component corresponding to the embedded groove and T-bolt. The static load test rod is provided with the center of the load test block, and the dynamic load test rod is provided with the inclined surface of the load test block.

[0032] A loader is provided above the test bench, and a loading rod is provided below the loader; the loading rod corresponds to the static load test rod for static load loading fatigue test, and the loading rod corresponds to the dynamic load test rod for dynamic load loading fatigue test; static load and dynamic load fatigue tests can be carried out on prefabricated assembled rail top air duct components, simulating the fatigue damage effect caused by long-term high-speed positive and negative wind pressure on the train, and can effectively verify the reliability of the rail top air duct connection.

[0033] The downward pressure fixing structure includes a pressure block 5, a pressure plate 4 and a group of columns. The lower end of the column is fixed on the test bench, the pressure plate is arranged between the two columns, and the pressure block is arranged on one column. The top surface of the prefabricated assembled rail top air duct component is pressed down and fixed by the pressure block and pressure plate on the column. The fixation is reliable and the operation is simple.

[0034] Furthermore, the prefabricated assembled rail top air duct component is placed on the test bench through the test pad 2, and the load test block is placed on the prefabricated assembled rail top air duct component through the groove fixed pad 6, so the test is stable and reliable.

[0035] The present invention also includes a loading tool for static load pressurization; preferably, the loading tool includes a pressure sensor 11 and a static load loading rod 12 and a tool frame 10 for being arranged on the air duct component, the static load loading rod passes through the pressure sensor and is arranged on the tool frame, and the lower end of the static load loading rod is arranged corresponding to the top of the T-bolt; further, the tool frame includes a pair of vertical plates and a horizontal plate arranged between the top of the pair of vertical plates, and the pressure sensor is arranged above the horizontal plate; it can effectively provide the accuracy of the test results.

[0036] The fatigue damage effect of the rail-top air duct during the full design service life is simulated under test conditions; the use of this design scheme can effectively verify the reliability of the rail-top air duct connection and provide theoretical support for practical applications.

[0037] Design requirements:

[0038] 1. Under the combined effects of the deadweight of prefabricated components, wind pressure generated by trains during reciprocating travel, catenary loads, and screen door loads, the fixed components of the prefabricated rail-top air duct at the simulated station will not fall off, become loose, or move, which would negatively impact the function of the components.

[0039] 2. Number of tests: 2 million.

[0040] Design conditions:

[0041] 1. Case Background: This test takes a certain city's subway station as an example. The rail-top air duct assembly adopts the Halfen Trough structure system. The design is 5 minutes per trip during off-peak hours and 2 minutes per trip during peak hours. The train arrival time is 30 seconds.

[0042] 2. Consider the stress state of the Halfen Trough structure system under the most unfavorable working conditions: the deadweight of the components, the wind pressure load of the components, the catenary load, and the screen door load are considered during train operation; at the same time, the width of the components is considered to take into account the effects of the three groups of screen door load-bearing components;

[0043] 3. Determination of the number of load-bearing components: According to the design requirements, a single Halfen trough component has 14 fixing bolts. Fatigue test is carried out at 75% of the load, i.e. 14 x 75% = 10 bolts. When a train enters the station, a single bolt is the resultant force of the above four forces, with a frequency of 5 / 2 min / time.

[0044] Load calculation: Load values: component self-weight load: 40kN; wind pressure load: 5kPa; vertical contact network load: 5kN; longitudinal contact network load: 9kN; shield door load: 10kN; consider a load factor of 1.3 when calculating.

[0045] Prefabricated components can be divided into two parts: static load and dynamic load. The static load is the deadweight of the component; the dynamic load is wind pressure, catenary load, and screen door load. Fatigue test load is divided into two working conditions:

[0046] ①. When the train enters the station, the wind pressure on the components is in the vertical direction and is negative. The component load is the component's deadweight, wind pressure load, catenary load, and screen door load.

[0047] The formula is as follows:

[0048] F 竖向Z =(F 自重 +F 风压 +F 接触网竖向 ) / 10×1.3

[0049] =(40KN+(-3.04×2.1×5)+5KN) / 10×1.3

[0050] =1.7004KN

[0051] F 水平向x =F 接触网 / 10=9KN / 10×1.3=1.17KN

[0052] F 水平向Y =F 屏蔽门 ×3 / 10×1.3=3.9KN

[0053] Calculate the resultant force: Ftotal = 4.41 kN

[0054] ②. When the train leaves the station and enters the section tunnel, the wind pressure on the component is vertically downward, the wind pressure is positive, and the component load is the component's deadweight, wind pressure load, and catenary load;

[0055] The formula is as follows:

[0056] F 竖向Z =(F 自重 +F 风压 +F 接触网竖向 ) / 10×1.3

[0057] =(40KN+(3.04×2.1×5)+5KN) / 10×1.3

[0058] =9.9996KN

[0059] F 水平向x =F 接触网 / 10=9KN / 10×1.3=1.17KN

[0060] F 水平向Y =F 屏蔽门 ×3 / 10×1.3=3.9KN

[0061] Calculate the resultant force: Ftotal = 10.79 kN

[0062] By comparison, it can be seen that the force on the train when leaving the station is greater than the force on the train when entering the station. Therefore, we focus on the force on the train when leaving the station and entering the section tunnel.

[0063] The stress conditions of the train entering the section tunnel are as follows:

[0064] The deadweight load of the component is 40kN, static load, Fstatic = Fdeadweight / 10 = 4kN

[0065] Catenary load and wind pressure are dynamic loads.

[0066] Therefore, the dynamic load: F 动Z =((3.04×2.1×5)+5kN×4) / 10×1.3=6.75kN

[0067] F 动X =F 接触网 / 10=1.17kN

[0068] F 动Y =F 屏蔽门 ×3 / 10=3.9kN

[0069] Dynamic load resultant force: F dynamic resultant = 7.88kN

[0070] Experimental Design:

[0071] 1. During the test, static load and dynamic load are considered separately.

[0072] 2. During the test, a continuous static load is applied to the embedded channel, and the static load is Fstatic = 4kN.

[0073] 3. During the test, static load is applied to the embedded channel and corresponding dynamic load is applied at the same time. The force parameters of dynamic load are: force range 0~7.88kN, frequency: 3Hz, number of times: 2 million times. The force direction is the spatial resultant force direction of dynamic three-way load; Figure 3 The force diagram of the component shown.

[0074] The combined force of the above three forces on a single bolt when the train enters the station is 5 / 2min / time.

[0075] Test Parameters: As indicated above, the train load is tested based on the combined force of three forces when entering and exiting the station. Considering the safety factor and time constraints of the test, the reciprocating frequency is increased to 3 times / s. With 24-hour continuous reciprocating operation, the load will be applied 259,200 times per day, requiring eight days to complete the 2 million load tests.

[0076] The fatigue testing method of the present invention comprises the following steps:

[0077] 1. Prefabricate concrete test blocks and embed the channel in the concrete test blocks. The size of the concrete test blocks is 450×450×400mm. Curing the concrete test blocks is done. The test can begin when the concrete strength reaches C50 level.

[0078] 2. Conduct the test according to the above design ideas:

[0079] 2.1. Under static conditions, a constant static load of 4kN is applied to the embedded channel in the vertical direction using a screw and a pressure sensor.

[0080] 2.2. After applying the static load, a dynamic load is applied in the spatial vector direction of the dynamic load resultant force. The dynamic load force parameters are: force range 0-7.88 kN, frequency: 3 Hz, number of times: 2 million times. The force direction is the spatial resultant force direction of the dynamic three-axis load.

[0081] 3. Observe whether the embedded grooves or T-bolts are damaged during the 2 million tests.

[0082] 4. Issue a test report.

[0083] Among them, the loading direction of the dynamic load is the spatial angle with the X-axis, Y-axis and Z-axis respectively: 82°, 60° and 31°, and the loading waveform of the dynamic load is a sine wave; according to this, the dynamic load is applied. After 2 million fatigue tests, the Hafen slots and bolts did not show any failure damage such as deformation, falling off and loosening. The fatigue test of the prefabricated rail top air duct component passed.

[0084] Through refined design and comprehensive testing, this detection method can effectively simulate the anti-fatigue damage effect of fixed components, improve the safety of component anchoring, reduce the risk of accidents during operation, and provide strong technical support for subsequent construction.

[0085] The above is only an illustration of a preferred embodiment of the present invention. The above technical features can be arbitrarily combined to form multiple embodiments of the present invention.

[0086] The present invention is described above by way of example in conjunction with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the scope of protection of the present invention.

Claims

1. A fatigue testing device for a prefabricated rail-top duct component, wherein the prefabricated rail-top duct component is provided with an embedded groove, and the embedded groove is provided with a T-bolt for fixing the component, characterized in that: The fatigue test device includes a test bench, a load test block, a static load test rod, a dynamic load test rod and a downward pressure fixing structure for fixing the air duct component; the prefabricated assembled rail top air duct component is arranged on the test bench and fixed by the downward pressure fixing structure, the load test block is arranged on the prefabricated assembled rail top air duct component with corresponding embedded grooves and T-bolts, the load test block is provided with an inclined surface, the static load test rod is arranged corresponding to the center of the load test block, and the dynamic load test rod is arranged corresponding to the inclined surface of the load test block.

2. The fatigue testing device for prefabricated rail-top air duct components according to claim 1, characterized in that: A loader is provided above the test bench, and a loading rod is provided below the loader.

3. The fatigue testing device for prefabricated rail-top air duct components according to claim 1, characterized in that: The downward pressing and fixing structure includes a pressing block, a pressing plate and a group of columns. The lower ends of the columns are fixed on the test bench, the pressing plate is arranged between the two columns, and the pressing block is arranged on one column.

4. The fatigue testing device for prefabricated rail-top air duct components according to claim 1, characterized in that: It also includes a loading tool for static load pressurization, which includes a pressure sensor, a static load loading rod, and a tool frame for being arranged on the air duct component. The static load loading rod passes through the pressure sensor and is arranged on the tool frame, and the lower end of the static load loading rod is arranged corresponding to the top end of the T-bolt.

5. The fatigue testing device for prefabricated rail-top air duct components according to claim 1, characterized in that: The prefabricated and assembled rail-top air duct component is placed on a test bench via a test pad.

6. The fatigue testing device for prefabricated rail-top air duct components according to claim 1, characterized in that: The load test block is arranged on the prefabricated assembled rail top air duct component through a groove fixing pad.

7. The fatigue testing device for prefabricated rail-top air duct components according to claim 4, characterized in that: The tooling frame includes a pair of vertical plates and a horizontal plate arranged between the tops of the pair of vertical plates, and the pressure sensor is arranged above the horizontal plate.

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