TWI863751B - Device and method for measuring permeability of reinforced fiber mat in resin transfer molding system - Google Patents

Abstract

A device and method for measuring the permeability of a reinforcing fiber mat in a resin transfer molding system. The measuring method is to coaxially place a ring-shaped reinforcing fiber mat in a circular mold cavity, compress the reinforcing fiber mat into a state where the pores gradually decrease in diameter inward or outward, and inject the resin into the mold cavity at a fixed liquid volume flow rate. The filling time and liquid pressure when the flow front of the resin moves to each radial position of the reinforcing fiber mat are analyzed and obtained. According to the relevant parameters of the mold cavity and the reinforcing fiber mat, the filling time when the flow front moves to each half-diameter position and the liquid pressure value, the König constant and permeability corresponding to each porosity are calculated. Through the design of this measurement method, the permeability corresponding to various porosities of the reinforcing fiber mat can be measured in a single resin filling process, which is very convenient and practical.

Description

Device and method for measuring permeability of reinforced fiber mat in resin transfer molding system

The present invention relates to a measuring device and method for resin transfer molding, and more particularly to a measuring device and method for measuring the permeability of a reinforcing fiber mat used in resin transfer molding.

Reinforced fiber mats such as glass fiber or carbon fiber are often combined with resins to make fiber composites. Such fiber composites have the characteristics of light weight and high mechanical strength, and are therefore widely favored by the transportation and sports industries.

Resin transfer molding technology is a common method used to make fiber composites. The cut fiber mats are stacked and placed inside the mold cavity, and then the thermosetting resin is injected to completely penetrate the fiber mats and harden to obtain the fiber composite. To use resin transfer molding to manufacture high-quality fiber composite products, it is extremely important to understand the permeability of the fiber mats at various porosities in advance. This is because it will affect the flow of resin in the fiber pores, the time required for filling, and the mechanical properties of the finished product.

The existing method for measuring the permeability of a reinforcing fiber mat is to place a reinforcing fiber mat of a specific porosity into a mold cavity of a transfer molding unit, and inject resin into the mold cavity at a fixed liquid volume flow rate, and calculate the permeability of the reinforcing fiber mat through the flow rate of the resin in the mold cavity, the pressure change in the mold cavity and the porosity of the reinforcing fiber mat. However, the current method can only obtain the permeability of a reinforcing fiber mat with a single porosity. If you want to know the permeability of reinforcing fiber mats with other porosities, you have to repeat multiple experiments, which is very time-consuming.

Therefore, an object of the present invention is to provide a measurement method for a resin transfer molding system that can improve at least one disadvantage of the prior art.

Therefore, the measurement method of the resin transfer molding system of the present invention is applicable to obtaining the permeability corresponding to various porosities of a reinforcing fiber mat in one measurement. The measurement method comprises the following steps:

The porosity adjustment step is to coaxially and horizontally place a circular reinforcing fiber mat in a circular mold cavity of a transfer molding unit. The height of the mold cavity of the transfer molding unit is gradually reduced from the center radially inward or outward, and the reinforcing fiber mat is gradually compressed radially inward or outward, so that the pores of the reinforcing fiber mat are gradually reduced radially inward or outward.

The step of analyzing and obtaining the porosity is to enable an analysis module to calculate and obtain the porosity (Φ) of the reinforcing fiber mat at different radial positions r of the mold cavity according to the unit area mass (A _w ) and density (D _f ) of the reinforcing fiber mat and the height (h) of the reinforcing fiber mat at the radial position r.

The resin injection step is to inject the resin into the center of the mold cavity with a resin syringe at a fixed liquid volume flow rate, so that the resin flows radially outward and penetrates into the pores of the reinforcing fiber mat.

An image capture step is to use an image capturer to capture an image of the resin flowing radially outward in the reinforcing fiber mat. The analysis module is used to analyze the image to obtain the filling time (t) when the flow front edge of the resin moves to each radial position of the mold cavity.

The step of acquiring the cavity pressure is to use a pressure sensor to measure the liquid pressure (P _i ) at the inner periphery of the reinforcing fiber mat at each filling time.

The step of analyzing and obtaining the Korenyi constant is to make the analysis module calculate the Korenyi constant (k c ) corresponding to each porosity according to the size parameters of the mold cavity, the unit area mass of the reinforcing fiber mat (A _w ), the porosity at each semi-diameter position, the filling time when the flow front moves to each semi-diameter position, and the liquid _pressure value at each filling time point.

The step of obtaining the permeability is to make the analysis module calculate the permeability corresponding to each porosity of the reinforcing fiber mat according to the Korenyi constant corresponding to each porosity of the reinforcing fiber mat.

The utility of the present invention is that through the design of the measuring method, the permeability corresponding to various porosities of the reinforcing fiber mat can be measured in one resin filling process, which is very convenient and practical.

Another object of the present invention is to provide a measuring device for a resin transfer molding system that can improve at least one disadvantage of the prior art.

The measuring device of the resin transfer molding system is suitable for measuring and obtaining the permeability corresponding to various porosities of a reinforcing fiber mat at one time. The reinforcing fiber mat is in a ring shape. The measuring device includes a transfer molding unit, a resin injector, a pressure sensor, an image capturer, and an analysis module.

The transfer molding unit defines a circular mold cavity in the vertical direction and is used to coaxially accommodate the reinforcing fiber mat. The height of the mold cavity is gradually increased or decreased from the center diameter to the outside. The transfer molding unit will gradually compress the reinforcing fiber mat in the direction of the mold cavity height decreasing.

The resin injector contains resin and can be driven to inject the resin into the area of the mold cavity on the inner circumference of the reinforcing fiber mat at a predetermined liquid volume flow rate, so that the resin radially permeates outward into the reinforcing fiber mat.

The pressure sensor can be used to measure the liquid pressure of the mold cavity at the inner periphery of the reinforcing fiber mat. The image capturer can be used to capture images toward the transfer molding unit to obtain images of the resin in the mold cavity penetrating and flowing in the reinforcing fiber mat.

The analysis module signal connects the pressure sensor and the image capturer, and includes an image analysis unit and a calculation unit. The image analysis unit can analyze the image to obtain the radial position of the flow front edge of the resin in the mold cavity and the corresponding filling time (t). The calculation unit can calculate the permeability corresponding to each porosity according to the porosity of each radial position relative to the center of the mold cavity after the reinforcing fiber mat is compressed, the filling time when the flow front edge moves to each radial position, the liquid pressure value at each filling time, and the size parameters of the mold cavity.

The utility model has the following advantages: through the structural design of the mold cavity of the transfer molding unit, and the design of the resin injector, the pressure sensor, the image capturer and the analysis module, the permeability of the reinforcing fiber mat under various porosity conditions can be measured through a single resin filling process, which is quite convenient and practical.

Referring to Figures 1, 2, and 3, an embodiment of a measuring device 200 for the permeability of a reinforcing fiber mat in a resin transfer molding system of the present invention is suitable for measuring the permeability of a reinforcing fiber mat 800 of multiple porosities at one time. The reinforcing fiber mat 800 is in the shape of a circular ring sheet with a thickness of _hi , an inner diameter of _ri , and an outer diameter of r _o . During implementation, the reinforcing fiber mat 800 can be a single sheet structure, or it can be composed of multiple sheets of reinforcing fiber objects stacked in layers. The density of the reinforcing fiber mat 800 is D _f , and the mass per unit area is A _w .

The measuring device 200 includes a transfer molding unit 3, a resin syringe 4 connected to the transfer molding unit 3, a pressure sensor 5 installed on the transfer molding unit 3, an image capturer 6 arranged above the transfer molding unit 3, and an analysis module 7 that connects the pressure sensor 5 and the image capturer 6 by signal.

The transfer molding unit 3 includes a lower mold 31, an upper mold 32 overlapping the lower mold 31, and a ruler 33 disposed on the upper mold 32. The lower mold 31 cooperates with the upper mold 32 to define a circular mold cavity 30 in the vertical axial direction. The radius of the mold cavity 30 is the same as the outer peripheral radius of the reinforcing fiber mat 800, so that the reinforcing fiber mat 800 can be coaxially disposed.

The lower mold 31 has a cavity bottom surface 310 defining the horizontal bottom edge of the cavity 30, and also has a filling hole 311 that penetrates up and down and is connected to the center of the cavity 30, and a plurality of exhaust holes 312 that penetrate up and down and are distributed in the vicinity of the cavity 30 to connect the cavity 30 with the outside.

The upper mold 32 is transparent and has a cavity top surface 320 which is spaced from the cavity bottom surface 310 and defines the top edge of the cavity 30. The cavity top surface 320 has a horizontal central surface 321 with a radius of _ri at the center of the cavity 30, and an annular surface 322 extending radially outward and downward from the circumference of the central surface 321.

The mold cavity 30 has a central zone 301 located below the central surface 321, and a permeation zone 302 surrounding the central zone 301 and decreasing in height radially outward. The height of the central zone 301 is equal to the thickness ( _hi ) of the reinforcing fiber mat 800, and the height of the permeation zone 302 is less than the thickness ( _hi ). Therefore, when the reinforcing fiber mat 800 is coaxially disposed in the mold cavity 30, the central zone 301 will correspond to the zone surrounding the inner periphery of the reinforcing fiber mat 800, and the reinforcing fiber mat 800 will actually be located in the permeation zone 302, so the annular portion 322 will compress the reinforcing fiber mat 800 located in the permeation zone 302 downward, so that the thickness of the reinforcing fiber mat 800 gradually decreases radially outward, and correspondingly, the porosity of the reinforcing fiber mat 800 gradually decreases radially outward.

The ruler 33 is disposed on the top surface of the upper mold 32 and extends outward relative to the center diameter of the mold cavity 30 to span the entire mold cavity 30 .

The resin injector 4 is connected to the filling hole 311 and can be activated to inject the resin 801 into the central section 301 of the mold cavity 30 at a predetermined liquid volume flow rate (q _i ) under pressure, so that the resin 801 diffuses radially outward from the central section 301 into the reinforcing fiber mat 800. Since the resin injector 4 is an existing component with many types and is not the focus of the present invention, it will not be described in detail.

The pressure sensor 5 is disposed in the central area 301 of the mold cavity 30 and adjacent to the inner periphery of the reinforcing fiber mat 800, and can be used to sense the liquid pressure generated by the resin 801 located at the inner periphery of the reinforcing fiber mat 800 (i.e., at the radius _ri ).

The image capturer 6 is disposed above the transfer molding unit 3 and can be used to capture images of the upper mold 32 and the ruler 33 downward, and can be used to capture the image of the resin 801 flowing in the mold cavity 30 and the image of the ruler 33.

1 , 3 , and 4 , the analysis module 7 includes an image analysis unit 71 , a calculation unit 72 , and a verification unit 73 .

The image analysis unit 71 can analyze the image obtained by the image capture device 6, and can analyze and identify a flow front edge 802 of the resin 801 when it flows in the reinforcing fiber mat 800 through currently known image recognition technology, and the flow front edge 802 corresponds to the scale of the ruler 33, thereby obtaining the radial position (r) of the flow front edge 802 of the resin 801 in the mold cavity 30.

According to fluid mechanics theory, when the radius of the mold cavity 30 is much larger than the thickness of the reinforcing fiber mat 800, the flow of the resin 801 in the mold cavity 30 in the reinforcing fiber mat 800 can be regarded as a quasi-steady-state thin shell flow of liquid in a porous medium, and the resin flow velocity is described by Darcy's law, which will be explained later. Due to the symmetry of the flow field, the resin 801 will present a one-dimensional radial flow, that is, a flow that diffuses uniformly from the central area 301 to the surroundings, so the overall shape of the flow front 802 of the resin 801 flowing in the reinforcing fiber mat 800 should be roughly circular. Once the shape deviation of the flow front edge 802 exceeds a certain range from the circle, it indicates that the transfer molding unit 3 is tilted. The image analysis unit 71 will further analyze the shape formed by the flow front edge 802 of the resin 801, and when it is determined that the shape deviates from the perfect circle by more than 1%, a warning message is issued, indicating that the experiment must be repeated.

The image recognition technology generally includes image binarization processing, noise filtering, boundary detection and recognition, etc. Since the image recognition technology is an existing image analysis and processing technology and there are many ways, it will not be described in detail.

The calculation unit 72 has a built-in calculation program that can be used to calculate the porosity (Φ) of the reinforcing fiber mat 800 at each half-diameter position r, the Korenyi constant (k _c ) corresponding to each porosity (Φ), and the permeability (K) corresponding to each porosity (Φ). The method for the calculation unit 72 to calculate the porosity, the Korenyi constant and the permeability is described as follows.

Regarding obtaining the porosity (Φ) at each radial position r of the reinforcing fiber mat 800. When the calculation unit 72 calculates the porosity (Φ) at a certain radial position r of the reinforcing fiber mat 800, the cavity volume and the total fiber volume at the radial position r are first calculated by the cylindrical shell method, and then the fiber volume fraction (Φ _f ) is obtained by dividing the two, see formula (1). h is the height of the mold cavity at the radius position r, as shown in formula (2), where m=(ho-hi)/(ro-ri), _ri is the radius of the inner periphery of the reinforcing fiber mat 800, _ro is the radius of the outer periphery of the reinforcing fiber mat 800, _hi is the thickness of the reinforcing fiber mat 800 at the radius position _ri , and _ho is the thickness of the reinforcing fiber mat 800 at the radius position r _o . 2πrdr is a calculus representation method, which means that a small distance dr is extended outward from position r, that is, position r+dr. The annular area from radius position r to radius position r+dr is 2πrdr. Multiplying the annular area by A _w gives the annular area fiber mass at the radius position r, and multiplying the annular area by the height gives the cavity volume at the radius position r.

Since the relationship between the fiber volume fraction (Φ _f ) and the porosity (Φ) is Φ _f +Φ = 1, the porosity (Φ) can be further obtained, see formula (3). Formula (1) Formula (2) Formula (3)

The following describes how to obtain the Korenyi constant (k _c ) corresponding to various porosities of the reinforcing fiber mat 800.

The momentum equation of the resin 801 (replaced by Darcy's law) is as shown in Formula (4). Wherein, v is the Darcy velocity of the resin, μ is the viscosity of the resin, K is the permeability of the reinforcing fiber mat 800, and P is the resin pressure in the reinforcing fiber mat 800. Formula (4)

Because the resin 801 flows symmetrically radially in the mold cavity 30, the flow rate of the resin 801 is , substituting into formula (4), we can get formula (5). Formula (5)

For the area of the reinforcing fiber mat 800 filled with the resin 801, the liquid pressure Pi at the radial position _ri (liquid pressure _Pi ) is integrated from the radial position ri (liquid pressure is 0) to the radial position r (liquid pressure is 0) where the flow front 802 is located, and then the liquid pressure _Pi at the radial position _ri can be obtained, as shown in formula (6). The pressure at the radial position r is expressed in gauge pressure, so the liquid pressure is 0. Formula (6)

Use the Kozeny-Carman formula, as shown in formula (7). Formula (7)

Substituting formulas (2), (3) and (7) into formula (6), we obtain formula (8). Formula (8)

After calculating formula (8), we can get formula (9). Formula (9)

The Korenyi constant (k _c ) under the porosity condition when the flow front 802 of the resin 801 moves to the radial position r can be calculated by formula (9). Wherein, _{Φ i} is the porosity at the radial position r _i of the reinforcing fiber mat 800, that is, the porosity at the inner periphery of the reinforcing fiber mat 800.

Next, the calculation unit 72 calculates a regression curve of the Korenyi constant and the porosity according to the porosities and the corresponding Korenyi constants at multiple radial positions of the reinforcing fiber mat 800. After the calculation unit 72 obtains the regression curve, the corresponding Korenyi constant can be compared with the regression curve.

Finally, the calculation module can further calculate the permeability (K) of the reinforcing fiber mat 800 having any porosity input according to the obtained Korenyi constant (k _c ) through formula (7).

The verification unit 73 can simultaneously analyze whether the mold cavity 30 or the resin injector 4 has leakage, or whether the internal pores of the reinforcing fiber mat 800 are not completely filled during the resin 801 filling process.

After the resin 801 flows into the reinforcing fiber mat 800, at the filling time t, when the resin 801 flows to the radial position r of the reinforcing fiber mat 800, the volume Q of the resin flowing into the reinforcing fiber mat 800 can be obtained using the calculus method, as shown in formula (10) Formula (10)

Since the resin injector 4 injects the resin 801 into the mold cavity 30 at a fixed liquid volume flow rate (q _i ), the volume Q of the resin injected into the mold cavity 30 can be obtained by multiplying the liquid volume flow rate by the filling time t _k . Since the mass is not destroyed, the formula (11) can be obtained. Q=q _i *t _k Formula (11)

The verification unit 73 can calculate the resin volume (Q) contained in the mold cavity 30 at the filling time (t) according to the liquid volume flow rate (q _i ) and the filling time (t) when the flow front edge 802 moves to the half-diameter position r. Then, the verification unit 73 calculates the theoretical time (t _k ) when the flow front 802 of the resin 801 moves to the radius position r through formula (11), and analyzes and determines the difference between the theoretical time (t _k ) and the filling time (t). If the difference between the theoretical time and the filling time is too large, it indicates that the resin injector 4 or the transfer molding unit 3 may leak, or the internal pores of the reinforcing fiber mat 800 are not completely filled. In this embodiment, the verification unit 73 will issue a warning message when it is determined that the difference between the theoretical time and the actual time exceeds 1 second, indicating that the test must be repeated.

Referring to FIGS. 1, 3, 4, and 5, the measuring device 200 of the resin transfer molding system of the present invention is used to analyze and obtain the permeability of the reinforcing fiber mat 800 under different porosities. An embodiment of the measuring method includes the following steps:

Porosity adjustment step 901: The reinforcing fiber mat 800 is coaxially and horizontally placed in the mold cavity 30 of the transfer molding unit 3, and the reinforcing fiber mat 800 is compressed to a thickness that gradually decreases in diameter outward, so that the pores of the reinforcing fiber mat 800 gradually decrease in diameter outward.

Analyze and obtain porosity step 902. The calculation unit 72 of the analysis module 7 calculates the porosity (Φ) of the reinforcing fiber mat 800 at the radial position r according to the size parameters of the mold cavity 30 and the total volume of the fiber at the radial position r after the reinforcing fiber mat 800 is compressed using formula (2) and formula (3).

Resin injection step 903 : The resin injector 4 injects the resin 801 into the central area 301 of the mold cavity 30 at a fixed liquid volume flow rate (qi), so that the resin 801 flows radially outward and penetrates into the pores of the reinforcing fiber mat 800 .

Image capture step 904. The image capture device 6 captures the image of the resin 801 flowing radially outward in the reinforcing fiber mat 800 and the image of the ruler 33. At the same time, the image analysis unit 71 of the analysis module 7 analyzes the image to obtain the filling time (t) when the flow front edge 802 of the resin 801 moves to each radial position of the mold cavity 30.

The cavity pressure acquisition step 905 is to make the pressure sensor 5 measure the liquid pressure (P _i ) of the inner periphery of the reinforcing fiber mat 800 at each filling time.

The Korenyi constant analysis step 906 is to cause the calculation unit 72 to calculate the Korenyi constant (k _c ) under the porosity condition when the flow front 802 of the resin 801 moves to the radius position r through formula (9).

Analyze and obtain the regression curve step 907. The calculation unit 72 calculates the regression curve of the Korenyi constant and the porosity according to the porosities and the corresponding Korenyi constants of the reinforcing fiber mat 800 at multiple radial positions.

In the step 908 of obtaining the permeability, the calculation unit 72 uses the regression curve to analyze the Korenyi constant according to each porosity of the reinforcing fiber mat 800. Then, the calculation unit 72 uses the porosity and the Korenyi constant to calculate the permeability corresponding to each porosity according to formula (7).

In practice, in another embodiment of the present invention, the calculation unit 72 is not required to establish the regression curve. In the step 908 of obtaining the permeability, the calculation unit 72 can obtain the corresponding Korenyi constant according to the porosity at a specific radius position, and then directly calculate the permeability of the reinforcing fiber mat 800 with the porosity using formula (7).

Resin flow front analysis step 909: The analysis module 7 analyzes the shape formed by the flow front 802 of the resin 801 in the image, and issues a warning message when it is determined that the deviation of the shape from a perfect circle is greater than or equal to 1%.

Verification step 910. The analysis module 7 calculates the resin volume (Q) contained in the mold cavity 30 at the filling time (t) according to the liquid volume flow rate (q _i ) and the filling time (t) when the flow front edge 802 moves to the specific radius position (r), and the analysis module 7 calculates the theoretical time (t k ) when the flow front edge 802 of the resin 801 moves to the specific radius position (r) according to formula ( ₁₁ ). The analysis module 7 then issues a warning message when the difference between the theoretical time (t _k ) and the filling time (t) is greater than 1 second.

In this embodiment, the height of the mold cavity 30 is designed to gradually decrease radially outward, so that the porosity of the reinforcing fiber mat 800 gradually decreases radially outward, and it is convenient to measure the permeability of the reinforcing fiber mat 800 with different porosities during one resin 801 filling process. However, in practice, in another embodiment of the present invention, the height of the mold cavity 30 can also be designed to gradually increase in diameter outward, so that the mold cavity 30 can process the reinforcing fiber mat 800 into a shape in which the pores gradually increase in diameter outward. Similarly, it can be used to measure the permeability of the reinforcing fiber mat 800 under various porosity conditions during a single resin 801 filling process.

In addition, in this embodiment, the upper mold 32 is designed to be transparent, and the image capturer 6 is directed downward to capture the image of the upper mold 32, so as to obtain the image of the resin 801 flowing in the mold cavity 30. However, in practice, in another embodiment of the present invention, the lower mold 31 may be designed to be transparent, and the image capturer 6 is directed upward to capture the image of the lower mold 31, so as to obtain the image of the resin 801 flowing in the mold cavity 30.

In summary, through the structural design of the mold cavity 30 of the transfer molding unit 3, the design of the resin injector 4, the pressure sensor 5, the image capture device 6 and the analysis module 7, and the design of the measurement method, the permeability of the reinforcing fiber mat 800 under various porosity conditions can be measured through a single resin 801 filling process, which is quite convenient and practical. Therefore, the measurement device 200 and the measurement method of the resin transfer molding system of the present invention are indeed a very innovative and convenient creation, and can indeed achieve the purpose of the present invention.

However, the above is only an embodiment of the present invention and should not be used to limit the scope of implementation of the present invention. All simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the content of the patent specification are still within the scope of the present patent.

200: Measuring device 3: Transfer molding unit 30: Mold cavity 301: Center section 302: Permeation section 31: Lower mold 310: Cavity bottom surface 311: Filling hole 312: Exhaust hole 32: Upper mold 320: Cavity top surface 321: Center surface 322: Ring surface 33: Ruler 4: Resin syringe 5: Pressure sensor 6: Image capturer 7: Analysis module 71: Image analysis unit 72: Calculation unit 73: Verification unit 800: Reinforced fiber mat 801: Resin 802: Flow front edge 901: Porosity adjustment step 902: Step of analyzing and obtaining porosity 903: Step of injecting resin 904: Step of capturing images 905: Step of capturing cavity pressure 906: Step of analyzing Korenyi constant 907: Step of analyzing and obtaining regression curve 908: Step of obtaining permeability 909: Step of analyzing resin flow front 910: Step of verification

Other features and effects of the present invention will be clearly presented in the embodiments with reference to the drawings, wherein: FIG. 1 is a side sectional view schematically illustrating the structure of an embodiment of the measuring device of the resin transfer molding system of the present invention; FIG. 2 is an incomplete side sectional exploded view schematically illustrating the structure of a transfer molding unit and a reinforcing fiber mat of the embodiment; FIG. 3 is a top view schematically illustrating the situation when the resin in a mold cavity of the embodiment radially permeates into the reinforcing fiber mat; FIG. 4 is a functional block diagram illustrating the functional architecture of the embodiment; and FIG. 5 is a step flow chart illustrating an embodiment of the measuring method of the resin transfer molding system of the present invention.

901: Porosity adjustment step

902: Step of analyzing and obtaining porosity

903: Resin injection step

904: Image capture step

905: Cavity pressure capture step

906: Steps to analyze Korreny's constant

907: Analyze and obtain the regression curve step

908: Steps to obtain permeability

909: Resin flow front analysis step

910: Verification steps

Claims (10)

A measurement method for a resin transfer molding system is applicable to obtaining the permeability corresponding to various porosities of a reinforcing fiber mat in one measurement, comprising the following steps: a porosity adjustment step, wherein a ring-shaped reinforcing fiber mat is coaxially and horizontally placed in a circular mold cavity of a transfer molding unit, wherein the height of the mold cavity of the transfer molding unit is gradually reduced from the center radially inward or outward, and the reinforcing fiber mat is gradually compressed radially inward or outward, so that the pores of the reinforcing fiber mat are gradually reduced radially inward or outward; A porosity analysis step, wherein an analysis module calculates the porosity (Φ) of the reinforcing fiber mat at different radial positions r of the mold cavity according to the unit area mass (A _w ) and density (D _f ) of the reinforcing fiber mat and the height (h) of the reinforcing fiber mat at the radial position r; A resin injection step, wherein the resin is injected into the center of the mold cavity at a fixed liquid volume flow rate so that the resin flows radially outward and penetrates into the pores of the reinforcing fiber mat; An image capture step, in which an image capturer captures an image of the resin flowing radially outward from the reinforcing fiber mat, and the analysis module analyzes the image to obtain the filling time (t) when the flow front edge of the resin moves to each radial position of the mold cavity; a mold cavity pressure capture step, in which a pressure sensor measures and obtains the liquid pressure (P _i ) of the inner periphery of the reinforcing fiber mat at each filling time; a Korenyi constant analysis step, in which the analysis module analyzes the image based on the size parameters of the mold cavity, the unit area mass (A _w ) and the porosity at each hemidiameter position, the filling time for the flow front of the resin to move to each hemidiameter position, and the liquid pressure value at each filling time point, to calculate the Korenyi constant (k _c ) corresponding to each porosity; and a permeability acquisition step, so that the analysis module calculates the permeability corresponding to each porosity according to the Korenyi constant corresponding to each porosity of the reinforced fiber mat. The measurement method of the resin transfer molding system as described in claim 1 also includes a step of analyzing and obtaining a regression curve, so that the analysis module calculates the regression curve of the König constant and the porosity based on the porosities at multiple radius positions and the corresponding König constants. In the step of obtaining the permeability, the analysis module calculates the König constant based on the regression curve, and calculates the corresponding permeability based on the König constant and the porosity. The measurement method of the resin transfer molding system as described in claim 2, wherein, in the porosity adjustment step, the pores of the reinforcing fiber mat are made to gradually decrease in diameter outward, and the measurement method further comprises a verification step, wherein the analysis module calculates the resin volume (Q) contained in the mold cavity at the filling time (t) according to the liquid volume flow rate (q _i ) and the filling time (t) when the flow front edge is displaced to a specific radial position (r), and the analysis module calculates the theoretical time (t _k ) when the flow front edge of the resin is displaced to the specific radial position according to the following formula, and the analysis module verifies the theoretical time (t k ) at the theoretical time (t _k ) and the filling time (t) is greater than 1 second, a warning message is issued, Q = q _i * t _k , m=( _ho - _hi )/( _ro - _ri ) wherein _ri is the radius of the inner periphery of the reinforcing fiber mat relative to the center of the mold cavity, _ro is the radius of the outer periphery of the reinforcing fiber mat relative to the center of the mold cavity, _Φi is the porosity at the inner periphery of the reinforcing fiber mat, _hi is the height of the mold cavity at the _ri radius, and _ho is the height of the mold cavity at the _ro radius. The measurement method of the resin transfer molding system as described in claim 1 also includes a resin flow front analysis step, so that the analysis module analyzes the shape formed by the flow front of the resin in the image, and issues a warning message when it is determined that the deviation of the shape from the perfect circle is greater than or equal to 1%. A measuring device for a resin transfer molding system is suitable for measuring the permeability corresponding to various porosities of a reinforcing fiber mat at one time. The reinforcing fiber mat is in the shape of a ring. The measuring device comprises: A transfer molding unit, which defines a circular mold cavity in the upper and lower axial directions and is used to coaxially accommodate the reinforcing fiber mat. The height of the mold cavity is gradually increased or decreased from the center diameter to the outside. The transfer molding unit will gradually compress the reinforcing fiber mat in the direction of the decreasing height of the mold cavity; A resin injector containing resin can be driven to inject the resin into the cavity at the inner periphery of the reinforcing fiber mat at a predetermined liquid volume flow rate, so that the resin radially permeates outward into the reinforcing fiber mat; A pressure sensor can be used to measure the liquid pressure of the cavity at the inner periphery of the reinforcing fiber mat; An image capturer can be used to capture images toward the transfer molding unit to obtain images of the resin in the cavity penetrating and flowing in the reinforcing fiber mat; and An analysis module, signal-connected to the pressure sensor and the image capturer, includes an image analysis unit and a calculation unit. The image analysis unit can analyze the image to obtain the radial position of the flow front edge of the resin in the mold cavity and the corresponding filling time (t). The calculation unit can calculate the permeability corresponding to each porosity according to the porosity of each radial position relative to the center of the mold cavity after the reinforcing fiber mat is compressed, the filling time when the flow front edge moves to each radial position, the liquid pressure value at each filling time, and the size parameters of the mold cavity. A measuring device for a resin transfer molding system as described in claim 5, wherein the transfer molding unit includes a lower mold and an upper mold superimposed on the lower mold and cooperating with the lower mold to define the mold cavity, and one of the lower mold and the upper mold is transparent, and the image capturer can capture images of the transparent upper mold or the lower mold. A measuring device for a resin transfer molding system as described in claim 6, wherein the transfer molding unit further includes a ruler disposed on the transparent lower mold or the upper mold and extending outward relative to the center diameter of the mold cavity, and the image capturer can capture the image of the flow front edge relative to the ruler. A measuring device for a resin transfer molding system as described in claim 5 or 7, wherein the image analysis unit can analyze the shape formed by the flow front edge of the resin and issue a warning message when it is determined that the deviation of the shape from a perfect circle is greater than or equal to 1%. A measuring device for a resin transfer molding system as described in claim 5, wherein the height of the mold cavity is gradually decreasing radially outward, and the analysis module further includes a verification unit. The verification unit can calculate the volume of resin (Q) contained in the mold cavity at the filling time (t) based on the liquid volume flow rate (q _i ) and the filling time when the flow front edge moves to a specific radial position (r). The verification unit will calculate the theoretical time (t _k ) when the flow front edge of the resin moves to the specific radial position according to the following formula, and the verification unit will issue a warning message when it is determined that the difference between the theoretical time (t _k ) and the filling time (t) is greater than 1 second, Q=q _i *t _k , m=( _ho - _hi )/( _ro - _ri ) wherein _ri is the radius of the inner periphery of the reinforcing fiber mat relative to the center of the mold cavity, _r0 is the radius of the outer periphery of the reinforcing fiber mat relative to the center of the mold cavity, _Φi is the porosity at the inner periphery of the reinforcing fiber mat, _hi is the height of the mold cavity at the radial position _ri , and _ho is the height of the mold cavity at the radial position _r0 . A measuring device for a resin transfer molding system as described in claim 6, wherein the lower mold or the upper mold has a plurality of exhaust holes connecting the periphery of the mold cavity with the outside world.

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