TWI509243B - A testing system and method of metal sheet - Google Patents

Description

Sheet metal test system and test method thereof

The invention relates to a metal sheet testing system, in particular to a testing system and a testing method thereof for integrating hydraulic expansion and forming limit experimental equipment of metal sheets.

In industrial manufacturing, sheet metal has been widely used in various fields, such as packaging, automotive and electronic consumer products, etc. In the process of manufacturing these products, material cost is the main production cost, in order to reduce production costs, Reducing the use of materials is the most straightforward method. However, reducing the material will inevitably affect the mechanical strength of the product. Therefore, in order to achieve the required mechanical strength and the material cost can be reduced, it is necessary to first understand the nature of the material, and then find the most suitable material according to its applicable scope and use conditions.

For sheet metal, the most widely used tensile test and forming limit experiments. However, in traditional engineering applications, tensile testing and forming limit experiments require the use of two different testing machines and a variety of test piece geometries, resulting in inconvenient testing and high costs.

In view of this, the present invention provides a metal sheet testing system for integrating a plurality of mechanical properties of a metal sheet. The system includes at least a clamping device, a hydraulic device and a measuring device. The clamping device has a first mold, a second mold and a super elastic body gasket, wherein the first mold and the second mold can hold any one of the test strip groups corresponding to the metal sheet, and the super The body gasket is detachably disposed between any one of the test strip sets and the second mold. The hydraulic device is coupled to the clamping device and provides a hydraulic pressure to the test strip set via the second die to expand it toward the first mold. The measuring device is respectively connected to the clamping device and the hydraulic device to instantly measure the instantaneous pressure of the hydraulic pressure and any one of the test strip groups The height of the expansion.

In an embodiment of the invention, wherein the measuring device comprises a first sensor and a second sensor, when the first mold and the second mold hold the first test piece, and the hydraulic device continuously provides hydraulic pressure In the test piece, the first sensor is used to measure the expansion height of the test piece, and the second sensor is connected to the second mold to measure the instantaneous pressure of the hydraulic pressure. At this time, the measuring device calculates the expansion height and the instantaneous pressure according to the expansion pressure. Data (for easy identification, defined here as the first data to distinguish).

In an embodiment of the invention, the plurality of grids are disposed on the test strips, and the amount of change of the grids of the test strips can be measured when the test strips are continuously subjected to hydraulic pressure to be broken. Measurement acquisition (for easy identification, defined here as the second data to distinguish).

Another object of the present invention is to provide a test method for the above metal sheet testing system, the method comprising at least the following steps: First, a test piece is held by the first mold and the second mold. Next, a super-body gasket is placed between the test piece and the second mold, and a hydraulic test piece is supplied by a hydraulic device to expand it. Then, the measuring device is used to instantly measure the expansion height of the test piece and the instantaneous pressure of the hydraulic pressure, and collect the expansion heights and the instantaneous pressures to calculate the first data according to the expansion heights and the instantaneous pressures. Wherein, the first data corresponds to a stress-strain relationship of one of the metal sheets.

In an embodiment of the present invention, the metal sheet testing method provided by the present invention further comprises the following steps: First, the first mold and the second mold are used to clamp a test piece provided with a plurality of grids, and then the hydraulic device is used. A hydraulic pressure is provided to the other first test piece to cause it to expand to rupture. Next, the amount of change of the grids on the test piece is measured to obtain second data to draw a forming limit map of the metal sheet.

Therefore, the advantages and spirit of the present invention can be further understood from the following detailed description of the invention and the accompanying drawings.

100‧‧‧Metal sheet test system

1‧‧‧Clamping device

11‧‧‧First mould

12‧‧‧Second mold

13‧‧‧Superbody gasket

2‧‧‧Hydraulic devices

21‧‧‧Hydraulic power unit

22‧‧‧Proportional pressure relief valve

3‧‧‧Measuring device

31‧‧‧First sensor

32‧‧‧Second sensor

33‧‧‧Control and analysis unit

4‧‧‧Testing group

H‧‧‧expansion height

p‧‧‧Hydraulic

S100~S208‧‧‧Metal sheet test method steps

1 is a schematic structural view of a metal sheet testing system according to a preferred embodiment of the present invention; FIG. 2 is a schematic structural view of a metal sheet testing system according to a preferred embodiment of the present invention; and FIG. 3 is a view showing a comparison of the present invention. A flow chart of a test method for a metal sheet test system of a preferred embodiment; FIG. 4 is a flow chart showing a test method of a metal sheet test system according to a preferred embodiment of the present invention; and FIG. 5 is a view showing a metal using a preferred embodiment of the present invention. Sheet forming test system The forming limit diagram obtained after the hydroforming limit test of the first test piece and the second test piece of the test piece group.

Please refer to FIG. 1 and FIG. 2, and both FIG. 1 and FIG. 2 are schematic diagrams showing the structure of a metal sheet testing system 100 according to a preferred embodiment of the present invention. As shown, the sheet metal testing system 100 includes at least one clamping device, a hydraulic device 2, and a measuring device 3. The clamping device has a first mold 11 , a second mold 12 and a super elastic body gasket 13 , and the super elastic body gasket 13 is detachably disposed between the first mold 11 and the second mold 12 . .

The hydraulic device 2 shown in Fig. 1 has a hydraulic power unit 21 and a proportional pressure relief valve 22, and the proportional pressure relief valve 22 communicates with the second mold 12 of the clamping device 1, when the experiment starts, The hydraulic power unit 21 is turned on, and the liquid is sent into the second mold 12 through the proportional pressure relief valve 22 to apply hydraulic pressure to any one of the test strip groups 4 to expand in the direction of the first mold 11, such as Figure 2 shows. When the hydraulic device feeds the liquid into the second mold 12, the super-body gasket 13 is first expanded by the hydraulic pressure, and the pressure is uniformly transmitted to any of the above-described test strips 4. That is, the expansion-deformed super-body spacer 13 forces any of the above-described test piece groups 4 to be deformed accordingly.

Still as shown in Fig. 1, the test strip group 4 comprises a plurality of test pieces of different geometric shapes, and corresponds to the metal plate to be tested. That is, in the present invention, a plurality of test pieces having the same properties as the metal sheet to be tested (for example, the same material and the same thickness, etc.) are subjected to subsequent tests to know the metal sheet. The mechanical properties are then used for industrial design.

The measuring device 3 shown in Fig. 1 is connected to the holding device 1 and the hydraulic device 2, respectively, to instantaneously measure the instantaneous pressure of the hydraulic pressure and the expansion height h of any one of the test strip groups 4. In a preferred embodiment of the invention, the measuring device 3 has a first sensor 31, a second sensor 32 and a control and analysis unit 33. Preferably, the first sensor 31 is a displacement sensor, and when the first mold 11 and the second mold 12 hold any one of the test strip groups 4, and the hydraulic device 2 continues to provide hydraulic pressure for the test. At the time of the film, the first sensor 31 is used to measure the expansion height h of the test piece. Preferably, the second sensor 32 is a pressure sensor and is coupled to the second mold 12 to measure the instantaneous pressure P of the hydraulic pressure. Finally, the above-described expansion height h and instantaneous pressure P are collected by the control and analysis unit 33 to calculate the first data. As for the above calculation process and operation details, it will be detailed later, and will not be described here.

In view of the above, after the metal sheet test system is completed, another object of the present invention is to provide a test method for the above test system. First, a hydraulic expansion test is performed to understand the stress-strain relationship of the metal sheet to be tested. After using the measuring device 3 shown in FIG. 1 to perform the instantaneous measurement to obtain the pressure ( P ) and the expansion height ( h ), the conventional analysis method is as follows: (1) and (2):

After obtaining the radius of curvature ρ and the thickness t of the dome, respectively, the equations (3) and (4) are taken to obtain a stress-strain relationship curve.

Further, please refer to FIG. 3, which shows a flow chart of the first data testing method of the metal sheet testing system according to a preferred embodiment of the present invention. As shown in the figure, the steps of the above test method include at least: first, the test piece S100 is held by the first mold 11 and the second mold 12. then, The superelastic spacer 13 is disposed between the test piece and the second mold 12, S102, and is hydraulically supplied to the test piece by the hydraulic device 2 to expand S104, and the expansion height of the test piece and the instantaneous pressure S106 of the hydraulic pressure are collected. The expansion height and the instantaneous pressure S108 calculate the first data S110 corresponding to the stress-strain relationship of the metal sheet.

Next, the metal sheet testing system provided by the present invention can perform a forming limit experiment after performing a hydraulic expansion test to obtain a true stress-strain relationship of the metal sheet to be tested. Using a test strip set provided with a plurality of grids, the test strips are continuously subjected to hydraulic pressure until they are broken, and the amount of change of the grids of the test strips is measured and converted into strains. The second data (ie, the forming limit map) is obtained.

Further, please refer to FIG. 4, which shows a flow chart of a second data testing method of the metal sheet testing system according to a preferred embodiment of the present invention. As shown in the figure, the steps of the above test method include at least: first, the test piece S200 is held by the first mold 11 and the second mold 12. Next, the superelastic spacer 13 is disposed between the test piece and the second mold 12, S202, and hydraulically supplied to the test piece by the hydraulic device 2 to expand to the crack S204, and the plurality of grids on the test piece are measured. The amount of change S206, the second data S208 corresponding to the forming limit map of the sheet metal is calculated. To draw a forming limit diagram of one of the metal sheets.

Still in the step shown in FIG. 4, in another embodiment, the super-body spacer 13 between the test piece and the second mold may be removed, so that the hydraulic pressure provided by the hydraulic device 2 is directly applied to the test piece. The pressure is continuously applied until it ruptures S204, and then the variation S206 of the plurality of meshes on the test piece is measured and the second data S208 is calculated from the change amount to draw a forming limit map of the metal plate.

In summary, the present invention provides a metal sheet testing system, which proposes a hydraulic expansion test using a super-elastic gasket as a hydraulic pressure transfer concept to integrate metal sheets and a forming limit experiment. The system provided by the invention successfully establishes an integrated material experimental equipment, which can obtain the stress-strain curve and the forming limit diagram of the metal sheet with a single experimental equipment, and effectively reduce the complexity and cost of the test.

The above is only the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention; all other equivalent changes or modifications which are not departing from the spirit of the present invention should be included in the following. Within the scope of the patent application.

100‧‧‧Metal sheet test system

1‧‧‧Clamping device

11‧‧‧First mould

12‧‧‧Second mold

13‧‧‧Superbody gasket

2‧‧‧Hydraulic devices

21‧‧‧Hydraulic power unit

22‧‧‧Proportional pressure relief valve

3‧‧‧Measuring device

31‧‧‧First sensor

32‧‧‧Second sensor

33‧‧‧Control and analysis unit

4‧‧‧Testing group

Claims (6)

A metal sheet testing system for integrating a plurality of mechanical properties of a metal sheet, the system comprising at least: a clamping device having a first mold, a second mold and a super elastic body gasket, wherein Between the first mold and the second mold, one of the test strip groups corresponding to one of the metal sheets may be clamped, and the super elastic body gasket is detachably disposed in any one of the test strip groups Between the second mold and the second mold; a hydraulic device connecting the clamping device and providing a hydraulic pressure to the one of the test strip groups via the second mold to expand in a direction toward the first mold; And a measuring device respectively connecting the clamping device and the hydraulic device to instantly measure an instantaneous pressure of the hydraulic pressure and an expansion height of any one of the test strip groups, wherein the measuring device comprises: a first sensor; and a second sensor, when the first mold and the second mold hold the test piece, and the hydraulic device continuously supplies the hydraulic pressure to the test piece, the first sensor is used for the first sensor Measuring an expansion height of the test piece, the second sensor Connected to the second mold measuring the hydraulic pressure of the moment, the measuring device of the system calculates the height of a first expanded data according to the instantaneous pressure. The system of claim 1, wherein the superelastic gasket has an area not less than any one of the test strip groups to uniformly transfer the hydraulic pressure to any one of the test strip groups. The system of claim 1, wherein the test piece is provided with a plurality of meshes, and a change of the plurality of meshes of the test piece is continued after the hydraulic pressure is continuously broken by the plurality of meshes. The amount can be measured to obtain a second data. A test method for a metal sheet testing system according to claim 1, comprising at least the following steps: clamping a test piece with the second mold by using the first mold; and setting a super elastic body gasket for the test Between the sheet and the second mold, a hydraulic pressure is applied to the test piece to expand the test piece; an expansion height of the test piece is instantaneously measured and an instantaneous pressure of the hydraulic pressure; and the expansion height is collected; With the momentary pressure; A first data is calculated according to the expansion height and the instantaneous pressure, and the first data corresponds to a stress-strain relationship of the metal sheet. The test method of claim 4, further comprising the steps of: clamping a test piece with the second mold by using the first mold; and providing a hydraulic pressure to the test piece by the hydraulic device to make the test The sheet is expanded to rupture; and a variation of the plurality of grids on the test piece is measured to obtain the second data to draw a forming limit map of the sheet metal. The test method of claim 4, further comprising the steps of: removing the superelastic spacer; clamping the test piece with the second mold by using the first mold; and providing the hydraulic pressure to the test piece Expanding the test piece to rupture; and measuring the amount of change of the plurality of meshes on the test piece to obtain the second data to draw a forming limit map of the metal plate.