CN103837408A - Device and method for testing tensile strength of carbon fiber monofilaments - Google Patents

Abstract

The invention discloses a device and a method for testing tensile strength of carbon fiber monofilaments. The testing device comprises a carbon fiber monofilament retainer, a weighing sensor, an actuating mechanism, a data acquisition card and a computer control system, wherein the carbon fiber monofilament retainer consists of a retaining plate, and an upper fixing plate and a lower fixing plate which are fixed at two ends of the retaining plate through bolts; the upper fixing plate is fixed on the actuating mechanism and moves along with the actuating mechanism; the lower fixing plate is fixed on the weighing sensor; the data acquisition card is connected with the actuating mechanism and the weighing sensor; the computer control system outputs motion speed and a direction signal to the actuating mechanism and is used for controlling the actuating mechanism; the computer control system acquires a signal of the weighing sensor through the data acquisition card. According to the device and the method for testing the tensile strength of the carbon fiber monofilaments, the problems that the clamping success rate is low and the testing cost is high in a conventional method can be effectively solved.

Description

A kind of carbon fiber monofilament tensile strength proving installation and method of testing thereof

Technical field:

The present invention relates to a kind of proving installation and method of testing thereof, relate in particular to a kind of carbon fiber monofilament tensile strength proving installation and method of testing thereof, it belongs to experimental provision and method field.

Background technology:

Carbon fiber because of its intensity high, modulus is good, density is low, and good high-temperature behavior, and is applied to the wild phase in various advanced composite materials, in Aero-Space, pressure vessel, wind-power electricity generation, the fields such as marine ship demonstrate superiority.In carbon fibre reinforced composite, Main Load is born by wild phase carbon fiber, and its intensity directly determines the intensity of composite element.Therefore, carbon fiber strength is made to test accurately and seem particularly important.

But, due to the micron-sized diameter of carbon fiber and intrinsic fragility, face a lot of difficulties for the test of carbon fiber monofilament tensile strength.The diameter of carbon fiber monofilament is generally at several microns to tens microns, and it destroys the magnitude of pulling force 10-1 ox, and so little magnitude has all proposed very high requirement to the control of pulling force sensor and topworks.In addition, carbon fiber is a kind of hard brittle material, in traditional method of clamping, is easy to fiber to cause damage.

Yao Jiangwei and Yu Weidong point out in " the external method of testing brief introduction of fragile fibre strength and extension property " (China's fine inspection the 8th phase in 2006), at present, for carbon fiber monofilament tensile strength proving installation, generally to carry out on special micro-power cupping machine, the pulling force sensor price that can meet the requirement of carbon fiber measuring accuracy is high, so traditional carbon fiber monofilament tensile strength testing experiment cost is generally higher.

In addition for carbon fiber monofilament tensile strength method of testing, be generally by the carbon fiber monofilament of fragility being sticked in to a papery sample card, then sample clip being held on the chuck of micro-power cupping machine.Such clamping process complicated operation, accuracy of alignment is low.Due to the flexibility of papery sample card, in clamping process, easily break carbon fiber.

Therefore, the necessary deficiency of prior art being improved to solve prior art.

Summary of the invention:

The present invention designs in order to solve existing proving installation costliness and method of testing complicated operation, the object of this invention is to provide one cheaply, carbon fiber monofilament tensile strength proving installation and method of testing thereof simple to operation, overcome the problem of the low and testing cost costliness of clamping success ratio in classic method.

The present invention adopts following technical scheme: a kind of carbon fiber monofilament tensile strength proving installation, it comprises carbon fiber monofilament retainer, LOAD CELLS, topworks, data collecting card and computer control system, described carbon fiber monofilament retainer is by holding plate, be secured by bolts in upper mounted plate and the bottom plate composition at described holding plate two ends, fixed plate is fixed in topworks and moves with topworks, described bottom plate is fixed in LOAD CELLS, described data collecting card is connected with topworks and LOAD CELLS, described computer control system by data collecting card output movement speed and direction signal in topworks in order to actuating mechanism controls, described computer control system gathers the signal of LOAD CELLS by data collecting card.

Described carbon fiber monofilament tensile strength proving installation also includes described bottom plate is fixed on to the lower grip block in LOAD CELLS.

Fixed plate is secured by bolts in topworks.

The present invention adopts following technical scheme: a kind of method of testing of carbon fiber monofilament tensile strength proving installation, it comprises the steps:

1) calibration load cell: LOAD CELLS is connected with data collecting card, data collecting card is connected with computer control system simultaneously, use standard test weight calibration load cell;

2) fixed carbon fibre single thread: upper mounted plate, bottom plate are installed on the two ends of holding plate, carbon fiber monofilament is pasted along the alignment on upper and lower fixing plate;

3) grip plate: using carbon fiber monofilament retainer as an entirety, upper mounted plate is installed in topworks, bottom plate is fixed in LOAD CELLS by lower grip block, take off holding plate, record now LOAD CELLS reading W1;

4) test: moved up and gathered the reading of LOAD CELLS until carbon fiber ruptures by computer control system control topworks, when fracture, LOAD CELLS reading is W2, obtains the pulling strengrth of carbon fiber monofilament by following formula

${\mathrm{\&sigma;}}_b=\frac{4(W_1-W_2)g}{\mathrm{\&pi;}{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="HDA0000475319430000012.png"\; state="\{\{state\}\}">d</figure-callout>}}^2}$

Wherein, g---the acceleration of weighing;

D---carbon fiber filament diameter.

The present invention has following beneficial effect:

(1) under same precision grade, LOAD CELLS price will be far below pulling force sensor price, the present invention is converted to tensile test the test of weight change cleverly, and then adopt LOAD CELLS to replace the pulling force sensor in traditional test device, ensureing, under the prerequisite of same test precision, to greatly reduce the cost of device;

(2) improved the stationary installation of carbon fiber, adopt the aluminium fixture of high rigidity to replace flexible papery fixture, after realizing a centering instrument, can carry out repeatedly the test of carbon fiber monofilament, simplify test process, this fixture has also avoided carbon fiber to be pulled off in clamping process, improves the success ratio of test.

Brief description of the drawings:

Fig. 1 is the schematic diagram of carbon fiber monofilament tensile strength proving installation of the present invention.

Fig. 2 is the structural drawing of carbon fiber monofilament tensile strength proving installation of the present invention.

Wherein:

1-topworks, 2-upper mounted plate, 3-holding plate, 4-bottom plate, 5-lower grip block, 6-LOAD CELLS.

Embodiment:

Please refer to shown in Fig. 1 and Fig. 2, carbon fiber monofilament tensile strength proving installation of the present invention comprises carbon fiber monofilament retainer, LOAD CELLS, topworks, data collecting card and computer control system, its computer control system is realized the collection to load cell signal and the driving to topworks by data collecting card.

Wherein carbon fiber monofilament retainer is made up of upper mounted plate 2, holding plate 3 and bottom plate 4.Wherein upper and lower fixing plate physical dimension is consistent, can be bolted on holding plate 3 by two respectively.Wherein the upper mounted plate 2 of carbon fiber monofilament retainer can be fixed in topworks 1 by two bolts, moves with topworks, realizes the stretching of carbon fiber monofilament is loaded.The bottom plate 4 of carbon fiber monofilament retainer is fixed in LOAD CELLS 6.Its computer control system gathers the signal of LOAD CELLS by the A/D interface of data collecting card.Simultaneous computer control system also the D/A interface output movement speed by data collecting card and direction signal to topworks, to realize the control to topworks.

The method of testing of carbon fiber monofilament tensile strength proving installation of the present invention, comprises following concrete steps:

1) calibration load cell: LOAD CELLS 6 is connected with data collecting card, data collecting card is connected with computer control system simultaneously, use standard test weight calibration load cell;

2) fixed carbon fibre single thread: upper mounted plate 2, bottom plate 4 are installed on holding plate 3, carbon fiber monofilament is pasted along the alignment on upper and lower fixing plate;

3) grip plate: using carbon fiber monofilament retainer as an entirety, upper mounted plate 2 is installed in topworks 1, bottom plate 4 is fixed in LOAD CELLS 6 by lower grip block 5, take off holding plate 3, record now LOAD CELLS reading W1;

4) test: moved up and gathered LOAD CELLS reading until carbon fiber ruptures by computer control system control topworks 1, when fracture, LOAD CELLS reading is W2, just can obtain the pulling strengrth of carbon fiber monofilament by following formula

${\mathrm{\&sigma;}}_b=\frac{4(W_1-W_2)g}{\mathrm{\&pi;}{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="HDA0000475319430000012.png"\; state="\{\{state\}\}">d</figure-callout>}}^2}$

Wherein, g---the acceleration of weighing;

D---carbon fiber filament diameter.

Embodiment mono-:

Adopt commercially available linear electric motors as topworks, commercially available LOAD CELLS as load-sensing unit, carry out in the steps below the test of carbon fiber filament strength:

1) device normalization: by LOAD CELLS 6 and data collecting card, computer control system is connected, with standard test weight calibration load cell 6;

2) fixed carbon fibre single thread: upper mounted plate 2, bottom plate 4 are installed on holding plate 3, carbon fiber monofilament is pasted along the alignment on upper and lower fixing plate;

3) grip plate: using carbon fiber monofilament retainer as an entirety, upper mounted plate 2 is installed on to the 1(of topworks to be driven by linear electric motors) on, bottom plate 4 is fixed in LOAD CELLS 6 by lower grip block 5, takes off holding plate 3, record now LOAD CELLS reading W1;

4) test: drive topworks 1 slowly to move upward until carbon fiber ruptures by computer control system control linear electric motors, when fracture, LOAD CELLS reading is W2, just can obtain the pulling strengrth of carbon fiber monofilament by following formula

${\mathrm{\&sigma;}}_b=\frac{4(W_1-W_2)g}{\mathrm{\&pi;}{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="HDA0000475319430000012.png"\; state="\{\{state\}\}">d</figure-callout>}}^2}.$

Embodiment bis-:

Employing universal electrical testing machine as device for measuring force, carries out the test of carbon fiber filament strength as driving mechanism, commercially available electronic balance in the steps below:

1) device normalization: electronic balance is placed under testing machine chuck, demarcates electronic balance with standard test weight;

2) fixed carbon fibre single thread: upper mounted plate, bottom plate are installed on holding plate, carbon fiber monofilament is pasted along the alignment on upper and lower fixing plate;

3) grip plate: using carbon fiber monofilament retainer as an entirety, bottom plate is fixed and is placed on electronic balance by lower grip block, mobile universal electrical testing machine upper grip is to upper mounted plate place and clamp upper mounted plate, then takes off holding plate, records now electronic balance reading W1;

4) test: drive topworks's 1 Slow loading until carbon fiber ruptures by computer control system control universal electrical testing machine, when fracture, electronic balance reading is W2, just can obtain the pulling strengrth of carbon fiber monofilament by following formula

${\mathrm{\&sigma;}}_b=\frac{4(W_1-W_2)g}{\mathrm{\&pi;}{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="HDA0000475319430000012.png"\; state="\{\{state\}\}">d</figure-callout>}}^2}.$

The above is only the preferred embodiment of the present invention, it should be pointed out that for those skilled in the art, can also make under the premise without departing from the principles of the invention some improvement, and these improve and also should be considered as protection scope of the present invention.

Claims (4)

1. a carbon fiber monofilament tensile strength proving installation, it comprises carbon fiber monofilament retainer, LOAD CELLS, topworks, data collecting card and computer control system, it is characterized in that: described carbon fiber monofilament retainer is by holding plate (3), be secured by bolts in upper mounted plate (2) and bottom plate (4) composition at described holding plate (3) two ends, fixed plate (2) is fixed on topworks (1) and above moves with topworks, described bottom plate (4) is fixed in LOAD CELLS (6), described data collecting card is connected with topworks (1) and LOAD CELLS (6), described computer control system by data collecting card output movement speed and direction signal in topworks in order to actuating mechanism controls, described computer control system gathers the signal of LOAD CELLS by data collecting card.

2. carbon fiber monofilament tensile strength proving installation as claimed in claim 1, is characterized in that: described carbon fiber monofilament tensile strength proving installation also includes described bottom plate (4) is fixed on to the lower grip block (5) in LOAD CELLS (6).

3. carbon fiber monofilament tensile strength proving installation as claimed in claim 2, is characterized in that: fixed plate (2) is secured by bolts in topworks (1).

4. a method of testing for carbon fiber monofilament tensile strength proving installation as claimed in claim 1, is characterized in that: comprise the steps

1) calibration load cell (6): LOAD CELLS (6) is connected with data collecting card, data collecting card is connected with computer control system simultaneously, with standard test weight calibration load cell (6);

2) fixed carbon fibre single thread: upper mounted plate (2), bottom plate (4) are installed on the two ends of holding plate (3), carbon fiber monofilament is pasted along the alignment on upper and lower fixing plate;

3) grip plate: using carbon fiber monofilament retainer as an entirety, upper mounted plate (2) is installed in topworks (1), bottom plate (4) is fixed on to LOAD CELLS (6) by lower grip block (5) upper, takes off holding plate (3), record now LOAD CELLS reading W1;

4) test: moved up and gathered the reading of LOAD CELLS (6) until carbon fiber ruptures by computer control system control topworks (1), when fracture, LOAD CELLS reading is W2, obtains the pulling strengrth of carbon fiber monofilament by following formula

${\mathrm{\&sigma;}}_b=\frac{4(W_1-W_2)g}{\mathrm{\&pi;}{d}^2}$

Wherein, g---the acceleration of weighing;

D---carbon fiber filament diameter.

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