CN107688001B - Mandrel peeling device and system and method for measuring prepreg tack by mandrel peeling - Google Patents

Abstract

The invention discloses a mandrel stripping device and a mandrel stripping system and method for measuring the viscosity of prepreg, belonging to the technical field of material physical property testing. The mandrel stripping device includes a base, a pulling mechanism, a sample plate for pasting prepreg samples, and a stripping mandrel; the stripping mandrel is rotatably mounted on the base, and the sample plate is slidably mounted on the On the base; the pulling mechanism includes a first pulley rotatably installed on the base and a traction rope straddling the first pulley. The first pulley is located at one end of the linear guide rail, and one end of the traction rope is fixed to one end of the sample plate. The other end is used to pull the sample plate to slide during the peeling process and the sliding speed is equal to the peeling speed of the prepreg sample. By cooperating with the universal testing machine, the stripping device can quantitatively measure the physical quantities that characterize the viscosity and bending stiffness of the prepreg.

Description

Mandrel peeling device and system and method for measuring prepreg tack by mandrel peeling

technical field

The present invention relates to the technical field of measuring physical properties of materials, in particular to a mandrel stripping device for measuring the viscosity and stiffness of prepregs, a prepreg viscosity measuring system constructed with the mandrel stripping device, and the measurement system based on the mandrel stripping device. Method for systematically testing prepreg tack.

Background technique

Prepreg viscosity refers to the incomplete bonding characteristics formed between prepreg and other object surfaces under short contact time and contact pressure, which is a key factor in determining whether prepreg is suitable for laying. In the composite material laying process, the prepreg is required to be within a reasonable viscosity range. When the viscosity is insufficient, it is easy to produce laying defects such as slippage and bridging; when the viscosity is too high, it is not conducive to the wrong layup. Adjusting the re-laying is also not conducive to the separation of the prepreg and the backing paper, and will bring difficulties to the transportation of the prepreg.

Therefore, accurate determination of the physical quantity used to characterize the viscosity of prepreg is one of the prerequisites for improving the lay-up quality of composite materials. However, due to the lack of accurate, effective and quantitative measurement methods, people usually In order to divide it into three grades of high, medium and low based on experience, or use some methods for qualitative measurement, such as: (1) Rolling ball method: put a plastic ball of specified size and quality on a 45° On the slope, let the ball roll down, and study the viscosity of the prepreg through the rolling situation; (2) Tear method: put two pieces of prepreg together, apply pressure, and then tear, under the specified load The time for the two pieces of prepreg to be completely torn apart is used as an index to characterize their viscosity; (3) paste separation method, etc.

In addition, due to the limitation of the characteristics of the prepreg itself, the traditional stiffness measurement device is not suitable for measuring the bending stiffness of the prepreg.

Contents of the invention

The object of the present invention is to provide a kind of mandrel stripping device that is used for quantitatively measuring the viscosity of prepreg;

Another object of the present invention is to provide a system for measuring the viscosity of prepreg with the mandrel peeling device constructed above;

Another object of the present invention is to provide a method for measuring the viscosity of prepregs using the above system.

In order to achieve the above purpose, the mandrel peeling device provided by the present invention includes a base, a pulling mechanism, a sample plate for sticking prepreg samples and a peeling device for forcing the prepreg sample to cling to the sample plate in the peeling transition area. mandrel; the peeling mandrel is rotatably installed on the base, and the sample plate is slidably mounted on the base through a guide rail slider mechanism, which includes a linear guide rail arranged along the length direction of the sample plate; the pulling mechanism includes a The first pulley rotatably installed on the base and the traction rope straddling the first pulley, the first pulley is located at one end side of the linear guide rail, one end of the traction rope is fixedly connected with one end of the sample plate, and the other end is used for stripping During the process, the sample plate is pulled to slide and the sliding speed is equal to the peeling speed of the prepreg sample.

During the measurement, install the stripping device on the universal testing machine, fix the other end of the traction rope on the clamp of the universal testing machine, and fix the stripped end of the prepreg sample on the clamp; During the peeling test, the sample plate and the peeled end of the prepreg sample are moved at the same speed by pulling the chuck. Therefore, the physical quantity that characterizes the viscosity of the prepreg can be obtained by recording through the universal testing machine for subsequent processing.

The specific solution is that the sample plate includes a detachable plate for pasting the prepreg sample and a supporting plate fixed on the slider of the guide rail slider mechanism, and the detachable plate is detachably installed on the supporting plate. Facilitate the sticking of prepreg samples during testing.

Another specific scheme is that a second pulley is rotatably installed on the base, and the second pulley is located on the side of the stripping mandrel adjacent to the first pulley; direction of travel, the second pulley is located downstream of the first pulley.

Another specific solution is that a layer of Teflon is attached to the peripheral surface of the peeling mandrel. Effectively reduce the friction between the prepreg sample and the stripping mandrel during the stripping process, and effectively ensure the accuracy of the test results.

The preferred solution is that the traction rope segment between the first pulley and the sample plate is parallel to the linear guide rail.

Another preferred solution is that the base is a U-shaped groove structure, and the groove wall is provided with a shaft hole for installing the pulley shaft and a shaft hole for installing the peeling mandrel shaft; the linear guide rail and the sample plate are placed in the U-shaped groove And arranged along the slot length direction.

In order to achieve the above another purpose, the present invention provides a mandrel peel-off system for measuring the viscosity of prepreg, including a universal testing machine and a peeling device mounted on the universal testing machine, the peeling device is the mandrel peeling device described in any of the above technical solutions ; The base is fixed on the support of the universal testing machine, the linear guide rail is arranged along the horizontal direction, the stripped end of the prepreg sample is clamped on the chuck of the universal testing machine, and the other end of the traction rope is fixed on the chuck; The stripped prepreg sample section is arranged vertically; along the traveling direction of the traction rope during the stripping process, the traction rope section between the chuck and the adjacent pulley is arranged vertically.

In order to achieve the above-mentioned yet another object, the mandrel peel-off method for measuring the viscosity of prepreg provided by the present invention is to use the above-mentioned system for measurement, which includes:

Material preparation step, arrange N prepreg test strips side by side, select the first test area and the second test area in the test area along its length direction, and keep N ₁ prepreg backing film in the first test area , keep N ₂ prepreg backing films in the second test area, and obtain prepreg samples, where N≥2, N ₁ ≠N ₂ , 0≤N ₁ ≤N and 0≤N ₂ ≤ N;

Sticking step, applying a predetermined pressure on the prepreg sample for a predetermined period of time, so that its back is attached to the sample plate;

In the initialization step, under the condition that the prepreg sample is not clamped by the chuck, the universal testing machine is started to pull the sample plate for an empty run test, and the displacement-force curve S1 is obtained;

In the peeling step, clamp the clamping end of the prepreg sample on the chuck, start the universal testing machine to peel the prepreg sample from the sample plate, and obtain the displacement-force curve S2;

The preprocessing step is based on the displacement, subtracting the curve S2 from the curve S1 to obtain the curve S3, and obtaining the peeling force P1 in the _first test area and the peeling force P2 in the _second test area from the curve S3;

Calculation steps, according to the formula Calculate the physical quantity that characterizes the viscosity of the prepreg, and B is the width of the prepreg test strip.

The specific scheme is that in the calculation step, according to the formula or Calculate the physical quantity that characterizes the bending stiffness of the prepreg. Therefore, the physical quantity used to characterize the bending stiffness of the prepreg can be accurately determined.

Another specific solution is N ₂ =0, N ₁ =N. It is convenient for subsequent calculation and preparation of prepreg samples.

Description of drawings

Figure 1 is a three-dimensional schematic diagram of a mandrel stripping device and a chuck with a prepreg sample installed in an embodiment of the present invention;

Fig. 2 is a schematic front view of the mandrel peeling device and the chuck with the prepreg sample installed in the embodiment of the present invention;

Fig. 3 is the working flowchart of the method for measuring the viscosity of prepreg by mandrel stripping in the embodiment of the present invention;

Fig. 4 is a schematic diagram of the back structure of the prepreg sample in the embodiment of the present invention;

Fig. 5 is a schematic diagram of the front structure of the prepreg sample in the embodiment of the present invention.

Detailed ways

The present invention will be further described below in conjunction with the embodiments and accompanying drawings.

Example

Referring to Fig. 1 and Fig. 2, the mandrel peel-off system for measuring the viscosity of prepreg according to the present invention includes a universal testing machine (only the chuck 5 is shown in the figure) and a mandrel peeling device 1 mounted on the universal testing machine.

The mandrel peeling device 1 includes a base 10 , a pulling mechanism, a sample plate 2 for pasting a prepreg sample 6 and a peeling mandrel 11 . The base 10 is a U-shaped groove structure, the groove wall is provided with a shaft hole in the middle region in the length direction, and the peeling mandrel 11 is rotatably mounted on the base 10 through the cooperation of the rotating shaft 12 and the shaft hole. In this embodiment, in order to reduce the friction between the peeling mandrel 11 and the prepreg sample 6 , a layer of Teflon is sprayed on the surface of the peeling mandrel 11 .

The sample plate 2 includes a detachable plate 22 for pasting the prepreg sample 6 and a supporting plate 21 fixed on the slider 32 of the guide rail slider mechanism 3, and the detachable plate 22 is detachably mounted on the supporting plate 21; The two parallel linear guide rails 31 in the guide rail slider mechanism 3 are placed in the U-shaped groove, and the length direction of it and the sample plate 2 are arranged along the groove length direction of the U-shaped groove; that is, the sample plate 2 slides through the guide rails. The block mechanism 3 is slidably mounted on the base 10 .

The pulling mechanism comprises a traction rope 41, a first pulley 42 and a second pulley 44; the groove wall at one end of the U-shaped groove structure is provided with a shaft hole for installing the rotating shaft 43, and the side of the stripping mandrel 11 adjacent to the rotating shaft 43 is provided with There is an axle hole for installing the rotating shaft 45, the first pulley 42 is rotatably installed on the rotating shaft 43, and the second pulley 44 is rotatably installed on the rotating shaft 45, that is, the first pulley 42 is positioned at one end side of the linear guide rail 31, and the second pulley 42 is rotatably installed on the rotating shaft 45. The second pulley 44 is located on the side of the peeling mandrel 11 adjacent to the first pulley 42 . One end of the traction rope 41 is fixedly connected to the end of the sample plate 2 adjacent to the first pulley 42, and the other end is sequentially wound on the first pulley 42 and the second pulley 43, and finally clamped by the chuck 5, that is, along the traction rope 41. The second pulley 44 is located downstream of the first pulley 42 in the direction of travel during peeling.

During use, the base is fixed on the support of the universal testing machine, and the linear guide rail 31 is arranged in the horizontal direction, and the stripped end of the prepreg sample 6 is clamped on the chuck 5 of the universal testing machine; During the stripping process, for the prepreg sample 6, the stripped prepreg sample section 603 is vertically arranged, that is, it is perpendicular to the prepreg sample section 601 pasted on the sample plate 2, and The transition region 602 between the prepreg sample section 603 and the prepreg sample section 601 is pressed against the sample plate 2 under the pressure of the peeling mandrel 11 , so that the peeling angle is 90 degrees.

Along the traveling direction of the traction rope 41 during the peeling process, the traction rope segment 411 between the sample plate 2 and the first pulley 42 is arranged in the horizontal direction, and the traction rope segment 412 between the first pulley 42 and the second pulley 44 Arranged in the horizontal direction, and the traction rope segment 413 between the chuck 5 and the adjacent second pulley 44 is arranged in the vertical direction, that is, the traction rope segment 413 is parallel to the prepreg sample segment 603, so that during the stripping process , the traction rope is used to pull the sample plate 2 to slide and its sliding speed is equal to the peeling speed of the prepreg sample 6.

Referring to Fig. 3, the method for measuring the viscosity and bending stiffness of prepregs using the above-mentioned measurement system includes material preparation step S1, pasting step S2, initialization step S3, stripping step S4, preprocessing step S5 and calculation step S6.

Material preparation step S1, arrange N prepreg test strips side by side, select the first test area and the second test area in the test area along its length direction, and keep N ₁ prepreg backing in the first test area film, keep N ₂ strips of prepreg backing film in the second test area, obtain prepreg samples, where N≥2, N ₁ ≠N ₂ , 0≤N ₁ ≤N and 0≤N ₂ ≤N.

In this embodiment, the process of preparing the prepreg sample 6 is, as shown in Fig. 4 and Fig. 5, arrange four carbon fiber prepreg test strips 61, 62, 63 and 64 side by side, and the four test strips The length is 2L+M, and the width is B.

As shown in Fig. 2, Fig. 4 and Fig. 5, the test strip front end 404 is used to be clamped on the chuck 5 in the stripping process, and its length is M, and the test area 607 is divided into a first test area 605 and a second test area 605. In the region 606 , the lengths of the two test regions are both L, which is half of the length of the test region 607 .

Keep the backing films 65, 66, 67 and 68 of the 4 test strips in the first test area 605, and tear off the other backing films. In this embodiment, the remaining backing films 65-68 are about the prepreg The line of symmetry 60 in the width direction of the sample 6 is arranged symmetrically, that is, N ₂ =0, N ₁ =4.

In the pasting step S2 , a predetermined pressure is applied to the prepreg sample 6 for a predetermined time, so that the back thereof is pasted on the sample plate 2 .

Detach the detachable plate 22 from the supporting plate 21, align the back of the prepreg sample 6 with the surface of the detachable plate 22 facing away from the supporting plate 21, and apply pressure to the prepreg sample 6 to make it stick To the detachable plate 22, there is no sticking force between the part that retains the backing film and the sample plate 2, so the peeling force does not include the stickiness factor of this part during the test.

In the initialization step S3 , under the condition that the chuck 5 does not clamp the prepreg sample 6 , the universal testing machine is started to pull the sample plate 2 to conduct an empty run test, and obtain the displacement-force curve S1 .

In the stripping step S4, clamp the clamping end of the prepreg sample 6 on the chuck 5, start the universal testing machine to peel the prepreg sample 6 from the sample plate 2, and obtain the displacement-force curve S2.

The detachable plate 22 on which the prepreg sample 6 is pasted is installed on the pallet 21, and the end 604 of the prepreg sample 6 is clamped by the chuck 5 of the universal testing machine.

Start the universal testing machine, peel the prepreg sample 6 from the sample plate 2, and record the displacement-force curve S2 during the peeling process.

Preprocessing step S5, based on the displacement, subtract the curve S2 from the curve S1 to obtain the curve S3, and obtain the peeling force P1 in the _first test area and the peeling force P2 in the _second test area from the curve S3 . In the curve S, select a stable force point in the curve corresponding to the displacement of the first test area 401 and the second test area 402 , that is, to obtain the peeling force P ₁ and the peeling force P ₂ .

Calculation steps, according to the formula Calculate the physical quantity that characterizes the viscosity of prepreg, and based on the formula or Calculate the physical quantity that characterizes the bending stiffness of the prepreg, and B is the width of the prepreg test strip.

The physical quantities F ₁ and F ₂ are used to characterize the viscosity and bending stiffness of the prepreg respectively; for the peeling force P ₁ , there is formula 1: NBF ₂ +(NN ₁ )BF ₁ =P ₁ ; and for the peeling force P ₂ , there is Formula 2: NBF ₂ +(NN ₂ )BF ₁ =P ₂ .

Combining Equation 1 and Equation 2, we can get or

In this embodiment, since N ₂ =0, N ₁ =4, it can be obtained or

_The calculated physical quantity F1 is used to represent the viscosity _of the prepreg, and the physical quantity F2 is used to represent the bending stiffness of the prepreg. Compared with the qualitative description in the prior art, it has the following advantages:

(1) The measuring method of the mandrel stripping device based on measuring prepreg viscosity and rigidity designed by the present invention adopts a universal testing machine to measure the force in the stripping process of the prepared prepreg, which can be directly quantified to obtain the predicted The stiffness of the prepreg is analyzed and calculated on this basis, realizing the characterization and measurement of the stiffness of the prepreg, making up for the lack of the current stiffness measurement device and method for the prepreg; and analyzing on this basis The calculation of the difference with the prepreg indirectly realizes the quantitative determination of the viscosity of the prepreg, and the method is simple, easy to implement, and easy to control;

(2) The measuring method based on the mandrel stripping device for measuring the viscosity and stiffness of the prepreg designed by the present invention is simple to prepare the required prepreg sample, easy to realize and high in efficiency.

The embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments, and can also be made without departing from the gist of the present invention within the scope of knowledge possessed by those of ordinary skill in the art. Variations.

Claims (8)

1. a kind of for measuring the mandrel stripping off device of prepreg viscosity, which is characterized in that the mandrel stripping off device includes bottom Seat, draw-off mechanism, the sample board for pasting prepreg test sample and for removing transitional region force prepreg test sample to be close to The removing mandrel of sample board；

The removing mandrel is installed in rotation on the pedestal, and the sample board is slideably pacified by guide rail slide block mechanism On the base, the guide rail slide block mechanism includes the linear guide arranged along the length direction of the sample board to dress；

The draw-off mechanism includes the first pulley being installed in rotation on the pedestal and across being wound in the first pulley Traction rope, the first pulley is located at the one end of the linear guide, one end of the traction rope and the sample board One end is fixedly connected, and for pulling in stripping process, the sample board slides the other end and sliding speed is equal to prepreg test sample Peeling rate；

The sample board includes portable plate for pasting prepreg test sample and the sliding block for being fixed on the guide rail slide block mechanism Supporting plate, the portable plate is removably mounted on the supporting plate；

Second pulley is rotatably mounted on the pedestal, the second pulley is located at the removing mandrel adjacent to described first The side of pulley, and it is located at the first pulley adjacent to the side of the removing mandrel；The traction rope is across being wound on described second On pulley, and the direction of travel along traction rope in stripping process, the second pulley are located at the downstream of the first pulley.

2. mandrel stripping off device according to claim 1, it is characterised in that:

One layer of Teflon is attached on the circumferential surface of the removing mandrel.

3. mandrel stripping off device according to claim 1 or 2, it is characterised in that:

Traction rope section between the first pulley and the sample board is parallel to the linear guide.

4. mandrel stripping off device according to claim 1 or 2, it is characterised in that:

The pedestal is U-type groove structure, and cell wall is equipped with for installing the axis hole of pulley spindle and for installing the removing core The axis hole of the shaft of axis；

The linear guide and the sample board are placed in U-type groove and arrange along flute length direction.

5. a kind of system of mandrel stripping type measurement prepreg viscosity, including universal testing machine and it is mounted in the universal testing machine On stripping off device, it is characterised in that:

The stripping off device is mandrel stripping off device described in any one of Claims 1-4 claim；

The pedestal is fixed on the support of the universal testing machine, and the linear guide is arranged in the horizontal direction, the preimpregnation The peel tip of material sample is clamped on the collet of the universal testing machine, and the other end of the traction rope is fixed on the collet On；

The prepreg test sample section removed vertically is arranged；

Along direction of travel of the traction rope in stripping process, traction rope section between the collet and adjacent pulleys vertically cloth It sets.

6. a kind of method of mandrel stripping type measurement prepreg viscosity, is measured using the system described in claim 5, is wrapped It includes:

N prepreg test-strips are arranged side by side, choose the first test section in test zone along its length by material preparation step Domain and the second test zone, retain N in the first test zone₁The backing film of prepreg, retains N in the second test zone₂ The backing film of prepreg obtains prepreg test sample, wherein N >=2, N₁≠N₂、0≤N₁≤ N and 0≤N₂≤N；

Gluing steps apply the predetermined pressure of scheduled duration to prepreg test sample, its back side are made to be sticked on sample board；

Initialization step, under conditions of collet does not clamp prepreg test sample, it is empty that starting universal testing machine pulls sample board to carry out Experiment is run, displacement-force curve S1 is obtained；

The clamping end of prepreg test sample is clipped on collet by strip step, and starting universal testing machine is by prepreg test sample from sample It is removed on plate, obtains displacement-force curve S2；

Pre-treatment step is subtracted each other curve S2 and curve S1 on the basis of displacement, obtains curve S3, and obtain from curve S3 Peeling force P in first test zone₁With the peeling force P in the second test zone₂；

Step is calculated, according to formulaThe physical quantity of computational representation prepreg viscosity, B are prepreg test-strips Width.

7. according to the method described in claim 6, it is characterized by:

In the calculating step, according to formulaOrComputational representation preimpregnation Expect the physical quantity of bending stiffness.

8. according to the method described in claim 6, it is characterized by: N₂=0, N₁=N.