An experimental system for measuring the transient bearing capacity of connectors in building envelope systems

Abstract

The present invention relates to a test system for measuring the transient bearing capacity of connectors in a building envelope system, characterized in that it includes: a driving device, a test cavity and a pressure sampling device. During the test, the driving device drives the piston (22) to move from the head end to the tail end of the test cavity, and the compressed gas generated between the piston (22) and the separating mechanism acts on the outer plate (102) through the ventilation holes, causing the outer plate (102) to tend to break away from the connector (103). The driving device continues to move until the whole composed of the connector (103), the inner plate (101) and the outer plate (102) is damaged. Compared with the prior art, the present invention makes up for the deficiency that the existing material mechanics testing machine cannot test the bearing performance of connectors under instantaneous overpressure. By recording the pressure change of the test cavity throughout the process through the pressure sampling device, the maximum bearing capacity of the connector can be obtained from the pressure change curve.

Description

Technical Field

[0001] The present invention relates to a test system for mechanical properties of components, and particularly to a test system for measuring the transient bearing capacity of connectors in a building envelope system. Background Art

[0002] The envelope system of a light steel structure building is a wall and roof system composed of profiled metal sheets, sandwich composite metal sheets, etc. covering the main load-bearing structure. Self-drilling screws (self-drilling tapping screws), self-tapping screws, blind rivets, etc. are commonly used as connectors to fix such envelope systems to the load-bearing structure. A typical connection form is as Figure 1 shown, where the outer layer of the sheet is connected to the inner layer of the load-bearing structure through connectors; this connection form bears the natural actions (typically wind load actions) acting on the envelope sheets, and also bears the self-weight action of the lightweight sheets.

[0003] The national design standard provides a calculation method for the bearing capacity of such connectors. The bearing capacity of the connection is related to the thickness and strength of the connected sheets and the diameter of the connectors. This calculation method is not applicable to the calculation of the bearing performance of connection components under rapid loading (such as blast overpressure) loads. Therefore, when designing for transient bearing capacity, the connection combination should be tested to measure its bearing capacity under rapid loading.

[0004] A relatively common measurement method is to use a material tensile testing machine as the test equipment and conduct tests on the connection combination using a loading frame similar to Figure 2 shown. The material mechanics testing machine mainly conducts tensile tests by clamping the test device with chucks. However, this method is static (quasi-static) loading and cannot reflect the bearing performance of connection components under rapid loading (such as transient overpressure) loads. Summary of the Invention

[0005] The purpose of the present invention is to overcome the above-mentioned defects existing in the prior art and provide a test system for measuring the transient bearing capacity of connectors in a building envelope system.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A test system for measuring the transient bearing capacity of connectors in a building envelope system, comprising:

[0008] A driving device,

[0009] A test cavity, the head end of the test cavity is connected to the driving device through a piston, a partition mechanism is fixed between the head end and the tail end, the partition mechanism is provided with air holes, and the connector to be tested fixes the inner sheet and the outer sheet on both sides of the partition mechanism;

[0010] Pressure sampling devices, which are respectively arranged on both sides of the separation mechanism, are used to record the pressure value of the test cavity during the test;

[0011] During the test, the driving device drives the piston to move from the head end to the tail end of the test cavity. The compressed gas generated between the piston and the separation mechanism acts on the outer plate through the air permeable holes, causing the outer plate to tend to separate from the connecting piece. The driving device continues to move until the whole composed of the connecting piece, the inner plate and the outer plate is damaged.

[0012] The test cavity includes a pressure cylinder and a connecting sleeve, and the connecting sleeve is detachably sleeved on the tail end of the pressure cylinder.

[0013] The separation mechanism is fixed between the tail end of the pressure cylinder and the inner wall of the connecting sleeve, and the inner wall of the connecting sleeve is provided with a positioning step for limiting the position of the separation mechanism.

[0014] The pressure cylinder and the connecting sleeve are cylindrical and are connected by threads.

[0015] An energy dissipation device is provided at the tail end of the test cavity.

[0016] The energy dissipation device includes a buffer pad and a stop block fixedly arranged between the outer plate and the tail end of the test cavity.

[0017] The energy dissipation device includes energy dissipation air holes.

[0018] The tail end of the test cavity is made of a transparent material.

[0019] A support slider is further arranged in the test cavity. The shape of the support slider matches the shape in the test cavity and is arranged on one side of the outer plate close to the tail end.

[0020] The system further includes a digital processing terminal connected to the pressure sampling device.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] (1) It makes up for the deficiency that the existing material mechanics testing machine cannot test the bearing performance of the connecting piece under the action of instantaneous overpressure. By recording the pressure change of the test cavity throughout the process with the pressure sampling device, the maximum bearing capacity of the connecting piece can be obtained through the pressure change curve.

[0023] (2) The test cavity includes a detachable pressure cylinder and a connecting sleeve. The separation mechanism is fixed between the tail end of the pressure cylinder and the inner wall of the connecting sleeve, and the connecting piece to be tested can be conveniently replaced.

[0024] (3) The pressure cylinder and the connecting sleeve are cylindrical and are connected by threads, which is convenient for disassembly and assembly and has a low manufacturing cost.

[0025] (4) An energy dissipation device is provided at the tail section of the test cavity to prevent the device and materials from being damaged and splashing.

[0026] (5) The tail end of the test cavity is made of a transparent material, which can visually observe the deformation of the tested component, control the force of the driving device, and reduce the number of tests.

[0027] (6) Support sliders are also provided inside the test cavity to define the sliding trajectory of the outer plate and improve the test accuracy. Description of the Drawings

[0028] Figure 1 It is a schematic diagram of the use of connectors for the building envelope system;

[0029] Figure 2 It is a schematic diagram of an existing material tensile testing machine;

[0030] Figure 3 It is a schematic diagram of the overall structure of the test system of Embodiment 1;

[0031] Figure 4 It is a schematic diagram of the sectional structure of the test cavity of Embodiment 1;

[0032] Figure 5 It is a schematic diagram of the disassembled mechanism of the test cavity of Embodiment 1.

[0033] Reference Signs:

[0034] 101: Inner plate

[0035] 102: Outer plate

[0036] 103: Connector

[0037] 21: Connecting rod

[0038] 22: Piston

[0039] 221: Piston ring

[0040] 31: Pressure cylinder

[0041] 311: First ventilation hole

[0042] 32: Front end cover

[0043] 33: Ventilation sieve plate

[0044] 34: Isolation sliding sleeve

[0045] 35: Annular support slider

[0046] 36: Connecting collar

[0047] 37: Tail end energy dissipation cylinder

[0048] 371: Energy dissipation air hole

[0049] 372: Energy dissipation pad

[0050] 373: Stop block

[0051] 374: Buffer cushion block

[0052] 38: Rear end cover

[0053] 381: Second ventilation hole

[0054] 41: Pressure gauge Detailed implementation mode

[0055] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and gives detailed implementation manners and specific operation processes, but the protection scope of the present invention is not limited to the following embodiments.

[0056] Embodiment 1

[0057] As Figures 1 to 3 shown, a test system for measuring the transient bearing capacity of building envelope system connectors includes a driving device, a test cavity, a pressure sampling device and a digital processing terminal. The specific structure is as follows:

[0058] The driving device uses a flywheel as an energy storage device. After the flywheel reaches the designed rotational speed, it is released to push the connecting rod 21 and the piston 22 to actuate.

[0059] The test cavity includes a cylindrical pressure cylinder 31 and a connecting sleeve 36. The pressure cylinder 31 is provided with a first ventilation hole 311. The head end of the pressure cylinder 31 is connected to the driving device through the piston 22. The piston 22 is sealed by a piston ring 221. The connecting sleeve 36 is detachably sleeved on the tail end of the pressure cylinder 31, and the two are connected by threads. The inner wall of the connecting sleeve 36 is provided with a positioning step. The ventilation sieve plate 33 is fixed at the positioning step by the tail end of the pressure cylinder 31. The tested connector 103 fixes the inner plate 101 and the outer plate 102 on both sides of the ventilation sieve plate 33, and the outer plate 102 blocks the ventilation holes on the ventilation sieve plate 33.

[0060] The ventilation sieve plate 33 has a central opening for placing the isolation sliding sleeve 34. If it is required in the design of the tested component that the inner load-bearing plate is in close contact with the outer envelope plate, the isolation sliding sleeve 34 is cancelled, and the inner load-bearing plate is processed by stamping, welding and other methods into a specimen with an opening embedded in the middle of the ventilation sieve plate 33 and the periphery lapped on the ventilation sieve plate 33.

[0061] The pressure cylinder 31 is made of metal and is threadedly connected to the front end cover 32. There is a hole on the front end cover 32 for the connecting rod 21 to pass through. The connecting rod 21 and the front end cover 32 are sealed with an oil seal. The maximum pressure that can be achieved inside the pressure cylinder is adjusted by the stroke of the piston 22.

[0062] The pressure sampling device includes two pressure gauges 41, which are fixed through the threaded holes on the cylinder wall. A dual-needle gauge with an indication of the maximum pressure is used to read the maximum pressure at the time of failure. A digital gauge with a sampling function is externally connected to a PC of a digital processing terminal for data processing, drawing a time-pressure curve, verifying the loading speed, and calculating the bearing capacity of the tested connecting component.

[0063] A support slider 35 is provided inside the test cavity. The shape of the support slider 35 matches the shape inside the test cavity and is arranged on one side of the outer plate 102 near the tail end.

[0064] An energy dissipation device is provided at the tail end of the test cavity. The energy dissipation device includes a tail end energy dissipation cylinder 37 threadedly connected to the tail end of the connecting sleeve 36, an energy dissipation air hole 371 on the tail end energy dissipation cylinder 37, a buffer cushion block 374 and a stop block 373 placed between the tail end energy dissipation cylinder 37 and the connecting sleeve 36, and an energy dissipation pad 372 inside the rear end cover 38. The rear end cover 38 is also threadedly connected to the tail of the tail end energy dissipation cylinder 37. A second ventilation hole 381 is provided on the rear end cover 38. The purpose of the energy dissipation device is to stop the annular support slider 35. The energy dissipation pad 372 is made of a loose material that can absorb impact. The tail end energy dissipation cylinder 37 is also made of metal or transparent organic material.

[0065] The tested connecting piece 103 can be a self-drilling screw, a self-tapping screw, a blind rivet, etc.

[0066] During the test, the driving device drives the piston 22 to move from the head end to the tail end of the test cavity. The compressed gas generated between the piston 22 and the separation mechanism acts on the outer plate 102 through the ventilation holes, pushing the annular support slider 35 to move to the right, making the outer plate 102 tend to separate from the connecting piece 103. At this time, the load is borne by the tested connecting piece 103. The driving device continues to move until the whole composed of the connecting piece 103, the inner plate 101, and the outer plate 102 is damaged. The component failure modes include: the connecting piece 103 is pulled out from the inner plate 101, the connecting piece 103 itself breaks, and the head of the connecting piece 103 is pulled out from the outer plate 102. No matter which mode, it will be manifested as a sudden drop in the time-pressure curve after the pressure gauge 41 samples. When the connecting sleeve 36 is made of transparent organic material, the failure mode can be directly observed during the test. Otherwise, it needs to be visually observed after disassembling the device after the test.

[0067] Embodiment 2

[0068] Different from Example 1, when the shapes of the inner and outer plate samples to be tested are non-circular (such as rectangular), the test cavity can use a rectangular cross-section, and in this case, each section of the unit is connected by a flange form. The rest is the same as in Example 1.

[0069] Example 3

[0070] Different from Example 1, the driving device uses a high-pressure air bag, a hydraulic device, etc. as the power source. The rest is the same as in Example 1.

Claims

1. An experimental system for measuring the transient bearing capacity of connectors in a building envelope system, characterized in that, Comprising: A driving device, A test cavity, the head end of the test cavity is connected to the driving device through a piston (22), a partition mechanism is fixed between the head end and the tail end, the partition mechanism is provided with air-permeable holes, and the connector (103) to be tested fixes the inner plate (101) and the outer plate (102) on both sides of the partition mechanism; A pressure sampling device, which is respectively arranged on both sides of the partition mechanism and is used to record the pressure value of the test cavity during the test; During the test, the driving device drives the piston (22) to move from the head end to the tail end of the test cavity, and the compressed gas generated between the piston (22) and the partition mechanism acts on the outer plate (102) through the air-permeable holes, so that the outer plate (102) has a tendency to break away from the connector (103), and the driving device continues to move until the whole composed of the connector (103), the inner plate (101) and the outer plate (102) is damaged; The test cavity includes a pressure cylinder (31) and a connecting sleeve (36), and the connecting sleeve (36) is detachably sleeved on the tail end of the pressure cylinder (31); The partition mechanism is fixed between the tail end of the pressure cylinder (31) and the inner wall of the connecting sleeve (36), and the inner wall of the connecting sleeve (36) is provided with a positioning step for defining the position of the partition mechanism; The pressure cylinder (31) and the connecting sleeve (36) are cylindrical, and the two are connected by threads.

2. The test system for measuring the transient bearing capacity of the building envelope system connectors according to claim 1, characterized in that The tail end of the test cavity is provided with an energy dissipation device.

3. The test system for measuring the transient bearing capacity of the building envelope system connectors according to claim 2, wherein, The energy dissipation device includes a buffer pad (374) and a stop block (373) fixedly arranged between the outer plate (102) and the tail end of the test cavity.

4. The test system for measuring the transient bearing capacity of the connectors of a building envelope system according to claim 2, wherein, The energy dissipation device includes an energy dissipation air hole (371).

5. The test system for measuring the transient bearing capacity of the connectors of a building envelope system according to claim 1, characterized in that, The tail end of the test cavity is made of a transparent material.

6. The test system for measuring the transient bearing capacity of building envelope system connectors according to claim 1, characterized in that, A support slider (35) is further arranged in the test cavity, and the shape of the support slider (35) matches the shape in the test cavity, and is arranged on one side of the outer plate (102) close to the tail end.

7. An experimental system for measuring the transient bearing capacity of connectors in a building envelope system according to claim 1, characterized in that, The system further includes a digital processing terminal connected to the pressure sampling device.

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