Small-energy double-conduit drop hammer type impact test device

Abstract

The invention provides a small-energy double-conduit drop hammer type impact test device. Comprising a drop hammer impact loading unit, a transient force and displacement testing unit and a data acquisition and display unit, the drop hammer impact loading unit comprises a bottom plate (1), a top plate (10), a stand column (4), an outer guide pipe (3), a hammer head (5), a heavy hammer (7) and a hollow guide pipe (9), the transient force and displacement testing unit comprises a piezoelectric acceleration sensor (6), a data line (8), a stabilized voltage supply and a charge amplifier; the data acquisition and display unit comprises a data acquisition card; and the data acquisition card is connected with the charge amplifier and is used for acquiring the magnitude of the transient resistance and carrying out data processing and display. The impact test device is simple in structure and low in cost, is based on an integrated structure of data acquisition, display and storage, and is an impact test device for mechanical experiment data of a flexible composite material in a small-energy test.

Description

Technical Field

[0001] The present invention relates to the field of impact test devices; in particular, it relates to a small-energy double-duct drop hammer impact test device. Background Art

[0002] Composite materials have the advantages of high specific strength, high specific stiffness, strong specific energy absorption, and good designability, and have been widely used in the fields of aerospace, transportation, building materials, etc. Composites such as carbon fiber / epoxy resin are typical brittle materials, usually showing linear elasticity before fracture without a plastic yield stage. This makes composite materials sensitive to impact damage, and flexible composite materials are particularly sensitive to sharp impacts.

[0003] There are many impact test methods, and the more widely used ones are pendulum impact tests, drop hammer impact tests, and tensile impact tests. The test results of the latter two only reflect the impact resistance of the material itself and cannot explain the influence of the material structure. The drop hammer device is suitable for the strength inspection of products such as plastics, glass, and ceramics. Usually, the impact kinetic energy is obtained by controlling the drop of a drop hammer from a certain height, and the experimental results are recorded through signal and data acquisition devices. Its advantages are simple structure, convenient operation, low cost, and wide application fields; its disadvantages are that the optional range of impact speed is small, and because it is driven by gravity, the experiment is greatly affected by inertial forces.

[0004] Currently, due to different test purposes and methods, the weights of the hammers in various drop hammer tests are different, and the lifting heights are also different. Especially, the lengths, shapes, and material types of the specimens are different. Therefore, there are no standardized products in China. Each user unit generally designs and manufactures a drop hammer testing machine by itself according to its own characteristics based on the drop hammer test principle or relevant standards. The impact testing machines developed by many universities or research institutes at home and abroad are all used to test and evaluate metal structures and hard materials, either being too bulky, having too large impact energy, or being too expensive, and there are few small-energy impact test devices for flexible composite materials. Summary of the Invention

[0005] The purpose of the present invention is to provide a small-energy double-duct drop hammer impact test device. The structure of the present invention is simple and the cost is low. Based on the integrated structure of data acquisition, display, and storage, it is an impact test device for mechanical experimental data of flexible composite materials in small-energy tests.

[0006] The present invention is achieved by the following technical solutions:

[0007] The present invention relates to a small-energy double-duct drop hammer impact test device, including three parts: a drop hammer impact loading unit, a transient force and displacement test unit, and a data acquisition and display unit;

[0008] Drop hammer impact loading unit, comprising: base plate 1, top plate 10, column 4, outer conduit 3, hammer head 5, weight 7, hollow conduit 9; one end of weight 7 is connected to hollow conduit 9, and the other end is connected to hammer head 5, and it is arranged inside outer conduit 3; the hammer head 5 can be replaced according to experimental needs to facilitate anti-puncture, anti-cutting or blunt impact experiments;

[0009] Transient force and displacement test unit, comprising: piezoelectric acceleration sensor 6, data line 8, regulated power supply and charge amplifier; the piezoelectric acceleration sensor 6 is tightly connected to the hammer head 5 by bolts, the output end of the piezoelectric acceleration sensor 6 is connected to the charge amplifier through the data line 8, and the regulated power supply provides the excitation voltage;

[0010] Data acquisition and display unit, comprising: data acquisition card; the data acquisition card is connected to the charge amplifier to obtain the magnitude of the transient resistance force and perform data processing and display.

[0011] Preferably, the weight 7 is a cylinder, and its outer surface is treated by precision grinding and lubrication. Appropriate lubrication is ensured to guarantee its fit with the outer conduit 3 and reduce the influence of the friction between them on the transient force.

[0012] Preferably, the base plate 1 and the top plate 10 are connected by the column 4 through screw threads and the perpendicularity is ensured. There are 4 adjusting nuts at the bottom of the base plate 1 to ensure the levelness of the entire experimental device.

[0013] Preferably, the piezoelectric acceleration sensor 6 is SD1407 of Beidaihe Electronic Research Institute.

[0014] Preferably, the data acquisition card is Advantech 1711 data acquisition card.

[0015] Preferably, there is a through hole on the top plate 10, and the outer conduit 3 is connected to the top plate 10 through a sleeve arranged on the through hole.

[0016] Preferably, the weight 7 is a hollow cylinder; the weight 7 falls from different heights or uses an acceleration device to obtain different impact speeds and energies.

[0017] Preferably, the data line 8 passes through the weight 7, and one end is connected to the piezoelectric acceleration sensor 6 and the other end is connected to the charge amplifier.

[0018] The working principle of the present invention: First, manually lift the weight 7 to a certain height by lifting the hollow conduit 9, and then let it go. The weight 7 descends inside the outer conduit 3. The piezoelectric acceleration sensor 6 transmits the data to the charge amplifier through the data line 8, and the amplified voltage signal is then collected, processed and displayed by the data acquisition card.

[0019] The present invention has the following advantages:

[0020] (1) The present invention is applicable to the small-energy (≤24 J) impact test of flexible composite materials, and can measure the drop hammers with different heights and weights, and impact the materials with different hammer heads, so as to simulate different impact modes in practice and evaluate the impact resistance and energy absorption characteristics of the materials;

[0021] (2) The present invention can collect test data in real time and display it. Through data processing, various curve data such as force-displacement, force-time, and acceleration-time can be obtained;

[0022] (3) The test device of the present invention is of ordinary vertical type, and the design of the components is modular, with a simple structure and easy processing. The equipment cost is economical and practical, and it is easy to expand the equipment performance according to the requirements for the accuracy and method of the measured parameters. Description of the Drawings

[0023] Figure 1 is a schematic structural diagram of the small-energy double-duct drop hammer impact test device of the present invention;

[0024] Figure 2 is a schematic structural diagram of the sleeve of the present invention;

[0025] Figure 3 is a software test setting diagram;

[0026] Figure 4 is a data storage setting;

[0027] Figure 5 is an impact curve diagram actually measured by the system of the present invention;

[0028] Reference Numerals in the Drawings:

[0029] 1 - bottom plate, 2 - gasket, 3 - outer duct, 4 - column, 5 - hammer head, 6 - piezoelectric acceleration sensor, 7 - weight, 8 - data line, 9 - hollow duct, 10 - top plate. Detailed Description of the Invention

[0030] The present invention will be described in detail below in conjunction with specific embodiments. It should be noted that the following embodiments are only further descriptions of the present invention, but the protection scope of the present invention is not limited to the following embodiments.

[0031] Embodiment

[0032] This embodiment relates to a small-energy double-duct drop hammer impact test device, as shown in Figure 1 shown, including: a drop hammer impact loading unit, a transient force and displacement test unit, and a data acquisition and display unit;

[0033] Drop hammer impact loading unit, comprising: a bottom plate 1, a top plate 10, columns 4, an outer conduit 3, a hammer head 5, a weight 7, and a hollow conduit 9; one end of the weight 7 is connected to the hollow conduit 9, and the other end is connected to the hammer head 5, and it is arranged inside the outer conduit 3; the hammer head 5 can be replaced according to experimental needs to facilitate anti-puncture, anti-cutting or blunt impact experiments;

[0034] Transient force and displacement testing unit, comprising: a piezoelectric acceleration sensor 6, a data line 8, a regulated power supply and a charge amplifier; the piezoelectric acceleration sensor 6 is tightly connected to the hammer head 5 by bolts, the output end of the piezoelectric acceleration sensor 6 is connected to the charge amplifier through the data line 8, and the regulated power supply provides an excitation voltage;

[0035] Data acquisition and display unit, comprising: a data acquisition card; the data acquisition card is connected to the charge amplifier to obtain the magnitude of the transient resistance force and perform data processing and display.

[0036] Furthermore, the weight 7 is a cylinder, and its outer surface is treated by precision grinding and lubrication. Appropriate lubrication is ensured to guarantee its fit with the outer conduit 3 and reduce the influence of the friction between them on the transient force.

[0037] Furthermore, the bottom plate 1 and the top plate 10 are connected by the columns 4 through screw threads and the perpendicularity is ensured. There are 4 adjusting nuts at the bottom of the bottom plate 1 to ensure the levelness of the entire experimental device.

[0038] Furthermore, the piezoelectric acceleration sensor 6 is SD1407 of Beidaihe Electronic Research Institute.

[0039] Furthermore, the data acquisition card is an Advantech 1711 data acquisition card.

[0040] Furthermore, a through hole is provided on the top plate 10, and the outer conduit 3 is connected to the top plate 10 through a sleeve arranged on the through hole. The sleeve structure is shown in Figure 2 as shown.

[0041] Furthermore, the weight 7 is a hollow cylinder; the weight 7 falls from different heights or uses an acceleration device to obtain different impact speeds and energies.

[0042] Furthermore, the data line 8 passes through the weight 7, and one end is connected to the piezoelectric acceleration sensor 6 and the other end is connected to the charge amplifier.

[0043] Test and measurement

[0044] Pure SiO2 powder, KH550-modified SiO2 powder, and KH570-modified SiO2 powder are respectively dispersed in polyethylene glycol (PEG) with an average molecular weight of 200 at appropriate volume fractions to prepare suspensions of different systems.

[0045] The fiber cloth used in the experiment is a single-layer Kevlar cloth with a surface density of about 0.0125 g / cm 2 and is uniformly cut into samples of 12 cm × 12 cm. The cut Kevlar cloth is immersed in the above three suspensions for 10 minutes, during which the ultrasonic cleaner is always used to assist in dispersion. To facilitate the fixation and preservation of the specimens, the Kevlar cloth impregnated with 4 different suspension systems is encapsulated with a polyethylene film on a FS3000 type hand-pressed plastic film sealing machine.

[0046] During the test, the 4-layer Kevlar cloth specimens impregnated with different suspension systems are tied to the non-elastic model clay liner 2 material with an elastic band. The falling height of the drop hammer is measured by the distance from the tip of the tool to the upper surface of the liner material. Considering that there are four layers of Kevlar in the specimen, the falling height is fixed at 0.3 m, and the falling speed of the tool is about 2.2 m / s. According to the relevant standard, the puncture point is at least 50 mm away from the edge of the specimen, and the distance between each puncture point is at least 75 mm. After triggering the manual trigger device, the tool falls through the specimen and penetrates into the clay, and the computer records all the data and the test is completed.

[0047] When collecting and processing data, the low-pass frequency of the charge amplifier needs to be adjusted to 10 k, and the amplification factor (gain) is adjusted to 10 times; the output voltage of the self-made regulated power supply of the photoelectric sensor is selected as 5 v; the wavescan software is adjusted to the analog parameter measurement mode (Fast AI, such as Figure 3 ), the frequency is selected as 30 k, the channel (chanstart) is selected as 1, the number (chancount) is selected as 2, and the data storage mode (AI save2disk, such as Figure 4 ) is selected, and then the test can be started.

[0048] It can be seen from Figure 5 that the Kevlar cloth impregnated with different suspension systems has much higher transient impact resistance than the pure Kevlar cloth and the clay without specimens. Among them, the Kevlar cloth impregnated with KH570-modified SiO2 suspension has the highest transient resistance.

[0049] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various deformations or modifications within the scope of the claims, which does not affect the essence of the present invention.

Claims

1. A low-energy double-conduit drop hammer impact test device, characterized in that: include: It consists of three parts: drop weight impact loading unit, transient force and displacement test unit and data acquisition and display unit; A drop hammer impact loading unit comprises: a bottom plate (1), a top plate (10), a column (4), an outer conduit (3), a hammer head (5), a heavy hammer (7), and a hollow conduit (9); one end of the heavy hammer (7) is connected to the hollow conduit (9), and the other end is connected to the hammer head (5), and is arranged in the outer conduit (3); The transient force and displacement test unit comprises: a piezoelectric acceleration sensor (6), a data line (8), a voltage-stabilized power supply and a charge amplifier; the piezoelectric acceleration sensor (6) and the hammer head (5) are tightly connected by bolts, the output end of the piezoelectric acceleration sensor (6) is connected to the charge amplifier through the data line (8), and the voltage-stabilized power supply provides an excitation voltage; The data acquisition and display unit includes: a data acquisition card; the data acquisition card is connected to the charge amplifier to obtain the magnitude of the transient resistance and perform data processing and display.

2. The low-energy double-conduit drop-weight impact test device according to claim 1, characterized in that: The weight (7) is a cylinder, and its outer surface is processed by fine grinding and lubrication.

3. The low-energy double-conduit drop-weight impact test device according to claim 1, characterized in that: The bottom plate (1) and the top plate (10) are connected by threads via the columns (4).

4. The low-energy double-conduit drop-weight impact test device according to claim 1, characterized in that: The piezoelectric acceleration sensor (6) is SD1407 from Beidaihe Electronics Research Institute.

5. The low-energy double-conduit drop-weight impact test device according to claim 1, characterized in that: The data acquisition card is Advantech 1711 data acquisition card.

6. The low-energy double-conduit drop-weight impact test device according to claim 1, characterized in that: The top plate (10) is provided with a through hole, and the outer conduit (3) is connected to the top plate (10) via a sleeve arranged on the through hole.

7. The low-energy double-conduit drop-weight impact test device according to claim 1, characterized in that: The weight (7) is a hollow cylinder.

8. The low-energy double-conduit drop-weight impact test device according to claim 1, characterized in that: The data line (8) passes through the weight (7), and one end is connected to the piezoelectric acceleration sensor (6), and the other end is connected to the charge amplifier.

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