Method and tooling for measuring fiber volume fraction of a bucket-shaped composite part with a flange

Abstract

The application provides a kind of flanging barrel-shaped composite part fiber volume fraction measurement method and measuring tool, the application measures the mass of flanging barrel-shaped composite part by tension sensor, then flanging barrel-shaped composite part is immersed in water, and the buoyancy that it receives is measured by sensor to calculate the volume of product, and then the average density of composite product is calculated, and then the fiber density of the preparation of the flanging barrel-shaped composite part and the resin matrix density can be calculated to obtain the average fiber volume fraction of the flanging barrel-shaped composite part, so as to realize the measurement of the average fiber volume fraction of flanging barrel-shaped composite part.The application can realize the measurement of the fiber volume fraction of flanging barrel-shaped composite part, and the measurement method provided by the application has higher accuracy and more intuitive test results compared with the measurement method in the prior art.

Description

Technical Field

[0001] This invention relates to the field of measuring equipment for composite material parts, and more specifically, to a method and measuring fixture for measuring the fiber volume fraction of a barrel-shaped composite material part with a flange. Background Technology

[0002] When measuring the average fiber volume fraction of the entire composite part, it is necessary to measure the total mass and total volume of the part and then calculate the average bulk density of the part. The average fiber volume fraction of the entire part is then calculated based on the bulk density of the reinforcing fibers and the bulk density of the resin matrix in the composite material.

[0003] When measuring the volume of composite material parts, if an optical fitting method is used to scan the entire surface of the part, for large and complex surface components, different regions of the component need to be scanned sequentially to form scanning models of each region. Then, appropriate fitting software is used to fit these multiple scanning models into a unified model. The volume of the component is then calculated based on this unified model. There is a deviation between the fitted model and the actual model. The larger the component volume, the more regions need to be scanned, and the more fitting operations are required. Therefore, the measurement deviation increases with the increase of the component volume, and the deviation is closely related to disturbances in the on-site measurement conditions. Thus, for large and complex surface components, the measurement results have a significant deviation problem. If the component has machined holes (such as acoustic liner holes), light may not be able to pass through the small holes during scanning, resulting in these machined holes not being scanned, which also affects the accuracy of the measurement results. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] The technical problem to be solved by this invention is that when measuring the fiber volume fraction of large and complex surface components using existing optical fitting methods, the measurement results have large deviations and low accuracy.

[0006] (II) Technical Solution

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] In a first aspect, the present invention provides a method for measuring the fiber volume fraction of a flanged barrel-shaped composite part, comprising the following steps:

[0009] Tension sensors are fixedly installed on the traction ropes connected to multiple lifting points of the flanged barrel-shaped composite material, and the multiple lifting points are set on the same horizontal plane.

[0010] One end of the traction rope is connected to the lifting point, and the other end of the traction rope is connected to the lifting device. The length direction of the traction rope is parallel to the Z direction of the flanged barrel-shaped composite material. The lifting device is equipped with a distance measuring sensor.

[0011] The lifting device lifts the flanged barrel-shaped composite material using the traction rope, and measures and calculates the mass Mp of the flanged barrel-shaped composite material using a tension sensor;

[0012] The flanged barrel-shaped composite material is hoisted into the annular water tank, and the flanged barrel-shaped composite material is kept at a preset distance from the bottom of the annular water tank.

[0013] Water is poured into the annular water tank until the water surface completely covers the top surface of the flanged barrel-shaped composite material. The buoyancy force on the flanged barrel-shaped composite material is measured by a tension sensor, and the position of the traction rope submerged in the water is marked. The volume Vp of the flanged barrel-shaped composite material is calculated based on the buoyancy force.

[0014] Calculate the average density of the flanged barrel-shaped composite material.

[0015] Based on the fiber density ρ f and resin matrix density ρ r The average fiber volume fraction V of the flanged barrel-shaped composite part was calculated. fm .

[0016] Preferably, the mass Mp of the flanged barrel-shaped composite part is calculated using the following formula:

[0017]

[0018] Among them, G t G represents the sum of tensile forces measured by multiple tension sensors. n This represents the tension value measured by the tension sensor at the nth suspension point, where g is the acceleration due to gravity.

[0019] Preferably, the volume Vp of the flanged barrel-shaped composite part is calculated according to the following formula:

[0020]

[0021] Among them, G t T represents the sum of tensile forces measured by multiple tension sensors. t ρ represents the sum of tensile forces measured by multiple tensile sensors when the water surface completely submerges the top surface of the flanged barrel-shaped composite component. w This represents the density of water at the corresponding ambient temperature, g is the acceleration due to gravity, and V is the velocity. L This indicates the volume of the portion of the tow rope submerged in the water.

[0022] Preferably, the average volume fraction of the fiber is calculated according to the following formula:

[0023]

[0024] Preferably, the method further includes the following steps:

[0025] When water is poured into the annular water tank, the water pouring is paused at certain intervals after the water contacts the flanged barrel-shaped composite material. After the readings of the tension sensors stabilize, the values ​​of each tension sensor are read to obtain the sensor measurement value T at the i-th water level. i , where i is a positive integer;

[0026] Calculate the volume of the flanged barrel-shaped composite material submerged in water at each water level.

[0027] The flanged barrel-shaped composite material has multiple interconnected segments along the Z-direction, with the distance between two adjacent water level heights considered as one segment. The measured volume of each segment is Δvi = v. i+1 -v i ;

[0028] The measured volume Δvi of each of the slit segments is compared with the theoretical volume of the digital model of the flanged barrel-shaped composite material in the corresponding slit segment to obtain the deviation value between the measured thickness of each slit segment and the theoretical thickness of the digital model.

[0029] Preferably, the method further includes the following steps:

[0030] The theoretical volume ΔVt of each slit segment is measured based on the 3D digital model of the part and compared with the measured volume ΔVi of each slit segment. Since the part is manufactured according to a set fiber path, the deviation in fiber volume fraction of each slit segment is mainly caused by the part thickness, i.e., ΔVi / ΔVt = di / dt, where dt is the theoretical thickness. The average measured thickness di of each slit segment is calculated. Since the fiber volume fraction is a function of the thickness di, the fiber volume fraction f(di) corresponding to a certain thickness range is fitted by experimentally determining the fiber volume fraction at different thicknesses. Therefore, the measured fiber volume fraction ΔVt in the Z-direction of each slit segment can be obtained. fm Then, based on the measured volume fraction of fibers in the Z-direction of each slit segment, the average density Δρi of the corresponding slit segment is calculated. The total mass m of the flanged barrel-shaped composite part is then calculated from the measured volume Δvi and the average density Δρi of each slit segment. 估 =∑(△ρi×△vi), where m 估 The reliability of the measurement data for each segment was evaluated by comparing it with Mp.

[0031] Preferably, the evaluation of the reliability of the measurement data for each segment includes the following steps:

[0032] When m 估 When the value of Mp is within the preset deviation range, the measurement data of each segment is reliable;

[0033] When m 估 If the value of Mp exceeds the preset deviation range, the measurement data of each segment is not reliable.

[0034] Secondly, the present invention also provides a measuring fixture for implementing the fiber volume fraction measurement method for the flanged barrel-shaped composite material as described in any of the above technical solutions, comprising a lifting device, multiple tension sensors, a traction rope, and an annular water tank; the lifting device is used to lift the flanged barrel-shaped composite material along the Z-direction, and the lifting device is equipped with a distance measuring sensor; multiple tension sensors are disposed on the traction rope connected to the lifting device; the traction rope is used to connect the lifting device and the flanged barrel-shaped composite material; the annular water tank is used to contain the flanged barrel-shaped composite material and water.

[0035] Preferably, it further includes a moving component connected to the lifting device for driving the lifting device to move along the X and Y directions.

[0036] Preferably, the height of the annular water tank is higher than the height of the flanged barrel-shaped composite material.

[0037] (III) Beneficial Effects

[0038] The above-described technical solution of the present invention has at least the following advantages:

[0039] 1. In this invention, the mass of the flanged barrel-shaped composite part is measured by a tensile sensor. The volume of the flanged barrel-shaped composite part is calculated by immersing it in water and measuring the buoyancy. The average density of the flanged barrel-shaped composite part can then be calculated. Combined with the density of the fiber body and the density of the resin matrix used to prepare the flanged barrel-shaped composite part, the average fiber volume fraction of the flanged barrel-shaped composite part can be calculated. This allows for the measurement of the average fiber volume fraction of the flanged barrel-shaped composite part. The method provided by this invention is particularly suitable for measuring the average fiber volume fraction of large-sized, complex-shaped parts. Compared with optical fitting methods, it does not require multiple scans and fittings of the part, and the test results have smaller deviations from the actual values ​​and higher accuracy.

[0040] 2. In this invention, compared with the optical scanning method that calculates the volume of a part through reverse modeling, the measurement method provided by this invention allows water to smoothly enter the machining holes when measuring a part with machining holes, so that the volume measurement is not affected by the machining holes of the part. The measurement operation and data processing are simpler and the results are more accurate.

[0041] 3. In this invention, the entire measurement process is primarily achieved through a tensile sensor. Since tensile sensors are readily available third-party standard measuring instruments, the client can select and use them independently, and the test results can be directly displayed on the tensile sensor, providing intuitive results. For large components, multiple small-range tensile sensors can be used for measurement. The deviation range of each calibrated tensile sensor is calibrated, and the deviation range is estimable when multiple tensile sensors are connected in parallel. Therefore, compared to the method of calculating the component volume through reverse modeling using optical scanning, the testing process of this invention can be intuitively reflected through the readings of the tensile sensors and the corresponding calculation formulas, resulting in higher reliability. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 This is a flowchart illustrating the fiber volume fraction measurement method for flanged barrel-shaped composite parts provided in this embodiment of the invention.

[0044] Figure 2 This is a structural schematic diagram of the flanged barrel-shaped composite material provided in an embodiment of the present invention.

[0045] Figure 3 This is a schematic diagram of the structure of the annular water tank provided in an embodiment of the present invention.

[0046] Figure 4 This is a schematic diagram of the measuring fixture provided in an embodiment of the present invention.

[0047] The labels for the attached figures are as follows:

[0048] 100. Flanged barrel-shaped composite component; 110. Tension sensor; 120. Distance sensor; 200. Traction rope; 300. Annular water tank; 400. Mechanism frame; 500. X-direction crossbeam guide rail; 600. Y-direction moving crossbeam; 700. Lifting device. Detailed Implementation

[0049] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0050] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be located directly on or indirectly on the other component. When a component is referred to as "connected to" another component, it can be directly or indirectly connected to the other component.

[0051] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate that the device or element must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0052] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating relative importance or the number of technical features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. The specific implementation of this invention will be described in more detail below with reference to specific embodiments:

[0053] like Figure 4 As shown, this embodiment of the invention provides a measuring fixture for implementing a method for measuring the fiber volume fraction of a flanged barrel-shaped composite part 100. It should be noted that, as... Figure 2 The flanged barrel-shaped composite component 100 shown is a resin-based composite component, with the reinforcement being fabric fibers (specifically, carbon fiber fabric fibers). Its composition includes resin materials for forming the resin matrix and fiber materials for forming the reinforcement. The flanged barrel-shaped composite component 100 has a relatively large actual size, is generally barrel-shaped, and has a flanged structure. The measuring fixture includes a lifting device 700, multiple tension sensors 110, a traction rope 200, and an annular water tank 300; the lifting device 700 is used to lift the flanged barrel-shaped composite component 100 along the Z-axis; multiple tension sensors 110 are mounted on the traction rope 200 connected to the lifting device 700; the traction rope 200 is used to connect the lifting device 700 and the flanged barrel-shaped composite component 100; the annular water tank 300 (e.g., ...) Figure 3(As shown) is used to accommodate the flanged barrel-shaped composite component 100 and water. It should be noted that this application does not limit the specific structural form of the lifting device 700; it can be a linear servo module, a crane, a hoist, a servo linear cylinder, etc. In this embodiment, the lifting device 700 is preferably a servo linear cylinder, with the output end of the linear cylinder connected to the traction rope 200.

[0054] like Figure 4 As shown, in one embodiment, a moving component is also included. This moving component is connected to the lifting device and is used to drive the lifting device to move along the X and Y directions. Specifically, the moving component includes a mechanism frame 400, an X-direction crossbeam guide rail 500, and a Y-direction moving crossbeam 600. The X-direction crossbeam guide rail is installed in the X direction of the mechanism frame 400. Several Y-direction moving crossbeams 600 capable of moving along the X direction are mounted on the X-direction crossbeam guide rail 500. Each Y-direction moving crossbeam 600 is equipped with a lifting device 700 capable of moving along the Z direction. The lifting device 700 can move on the Y-direction moving crossbeam 600. Specifically, in this embodiment, the X direction corresponds to the X-axis direction of the three-dimensional spatial coordinate system, the Y direction corresponds to the Y-axis direction of the three-dimensional spatial coordinate system, and the Z direction corresponds to the Z-axis direction of the three-dimensional spatial coordinate system. By setting up the moving component, the lifting device can be moved in the xy plane. Combined with the Z-axis movement of the lifting device, the flanged barrel-shaped composite material part 100 can be lifted and transported to a designated position in the three-dimensional space of the mechanism frame 400.

[0055] In one embodiment, the height of the annular water tank 300 is higher than the height of the flanged barrel-shaped composite material 100. This is so that the annular water tank 300 can accommodate the entire flanged barrel-shaped composite material 100, thereby facilitating the complete submersion of the top surface of the flanged barrel-shaped composite material 100 when water is poured into the annular water tank 300.

[0056] like Figure 1 As shown, this embodiment of the invention provides a method for measuring the fiber volume fraction of a flanged barrel-shaped composite material, used to measure, for example... Figure 2 The fiber volume fraction of the flanged barrel-shaped composite part 100 shown is determined by the following steps:

[0057] Distance sensors 120 are installed on multiple lifting devices 700 to measure the distance from the end face of the lifting device 700 to the Y-direction moving beam 600, ensuring that multiple lifting points are positioned on the same horizontal plane. Specifically, when the lifting device 700 lifts the flanged barrel-shaped composite component 100, it ensures that the bottom surface of the flanged barrel-shaped composite component 100 is always perpendicular to the Z-direction, that is, that the height direction of the flanged barrel-shaped composite component 100 is parallel to the Z-direction. More specifically, before installing and fixing the tension sensors, it is necessary to first determine the number of lifting points and the specifications of the tension sensors to be used based on the geometric dimensions and estimated weight of the flanged barrel-shaped composite component 100. Next, the tension sensor needs to be calibrated. A calibration range is selected within the tension sensor's measurement range, and several calibration measurement points are chosen within this range. Standard weights are used to measure the tension sensor at the corresponding calibration measurement points. Multiple tension sensors are electrically connected to an industrial control computer. A corresponding program is set in the industrial control computer to compensate for the measurement error of the tension sensor. For the remaining measurement points within the calibration range, linear interpolation of the measurement error at the calibration points is used for calculation and compensation. Furthermore, multiple distance sensors 120 can be installed on the lifting device 700 (the positions of the distance sensors 120 are set as follows...). Figure 3 As shown, after the flanged barrel-shaped composite component 100 is lifted, the lifting device corresponding to each lifting point is driven to move along the Z-axis to adjust the value of each distance sensor 120 to the specified value, thereby setting multiple lifting points on the same horizontal plane. In this embodiment, a small-range tension sensor is preferably used for measurement. The small-range tension sensor has a small deviation range and is easy to calibrate accurately. Using multiple calibrated small-range tension sensors in parallel for measurement partially cancels out the positive and negative fluctuations, improving the accuracy of volume measurement of the flanged barrel-shaped composite component 100.

[0058] One end of the traction rope 200 is connected to the flanged barrel-shaped composite component 100, and the other end of the traction rope 200 is connected to the tension sensor 110 on the lifting device. The length direction of the traction rope is parallel to the Z-direction of the flanged barrel-shaped composite component 100. The lifting device is equipped with a distance sensor 120, which is used to measure the distance between the end face of the lifting device 700 and the Y-direction moving crossbeam 600. Specifically, the hook below the tension sensor is connected to the traction rope. Both ends of the traction rope are lifting rings. Multiple traction ropes used to lift the flanged barrel-shaped composite component 100 use the same length specification. One end of the traction rope passes through the bottom of the flanged barrel-shaped composite component, goes around the flanged barrel-shaped composite component, and passes through the inside of the flanged barrel-shaped composite component. It is then hoisted together with the lifting ring at the other end of the traction rope on the hook below the tension sensor, thereby realizing the hoisting and fixing of the flanged barrel-shaped composite component. More specifically, the traction rope is preferably a steel wire rope or steel cable, and the part in contact with the flanged barrel-shaped composite material is equipped with a rubber sleeve or PTFE sleeve to isolate the traction rope from the flanged barrel-shaped composite material, so as to avoid damage to the flanged barrel-shaped composite material during hoisting. The traction rope is made of a material that does not get wetted by water.

[0059] The lifting device lifts the flanged barrel-shaped composite component 100 using a traction rope 200. A tension sensor measures and calculates the mass Mp of the flanged barrel-shaped composite component 100. Specifically, when calculating Mp, the weight of the traction rope 200 needs to be subtracted. This can be achieved by setting the zero-force value displayed by the tension sensor to the weight of the traction rope 200 during adjustment, or by subtracting the weight of the traction rope 200 from the value displayed by the tension sensor when calculating the final Mp value.

[0060] The flanged barrel-shaped composite material 100 is hoisted into the annular water tank 300, with the flanged barrel-shaped composite material 100 maintaining a preset distance from the bottom of the annular water tank 300, so as to ensure that the flanged barrel-shaped composite material 100 is in a suspended state.

[0061] Water is poured into the annular water tank 300 until the water surface completely covers the top surface of the flanged barrel-shaped composite component 100. The buoyancy force on the flanged barrel-shaped composite component 100 is measured by the tension sensor and the position of the traction rope 200 submerged in the water is marked. The volume Vp of the flanged barrel-shaped composite component 100 is calculated based on the buoyancy force.

[0062] Calculate the average density of 100mm flanged barrel-shaped composite material.

[0063] Based on the fiber density ρ f and resin matrix density ρ r The average fiber volume fraction V of the flanged barrel-shaped composite part 100 was calculated. fmCompared to optical scanning methods that calculate part volume through reverse modeling, which sometimes misses machined holes (such as acoustic liner holes) during optical scanning, resulting in a measured volume larger than the actual volume of the part, this measurement method uses water to measure the part volume. Water can easily enter the machined holes, making the volume measurement unaffected by the machined holes. The measurement operation and data processing are simpler, and the results are more accurate.

[0064] In one embodiment, the mass Mp of the flanged barrel-shaped composite part 100 is calculated using the following formula:

[0065]

[0066] Among them, G t G represents the sum of tensile forces measured by multiple tension sensors. n This represents the tension value measured by the tension sensor at the nth suspension point, where g is the acceleration due to gravity.

[0067] In one embodiment, the volume Vp of the flanged barrel-shaped composite part 100 is calculated according to the following formula:

[0068]

[0069] Among them, G t T represents the sum of tensile forces measured by multiple tension sensors. t ρ represents the total tensile force measured by multiple tension sensors when the water surface completely submerges the top surface of the flanged barrel-shaped composite component 100. w This represents the density of water at the corresponding ambient temperature, g is the acceleration due to gravity, and V is the velocity. L This indicates the volume of the portion of the tow rope 200 submerged in water. Since the tow rope is made of a material that does not wet with water, its volume does not change when it is submerged in water. Specifically, we can measure the volume VL of the submerged portion of the tow rope by immersing the submerged portion of the tow rope in a graduated cylinder filled with water and measuring the difference in the height of the rise in the water level within the graduated cylinder.

[0070] In one embodiment, the average fiber volume fraction is calculated according to the following formula:

[0071]

[0072] In one embodiment, the following steps are also included:

[0073] When water is poured into the annular water tank, the water pouring is paused at certain intervals after the water touches the flanged barrel-shaped composite part 100. After the readings of the tension sensors stabilize, the values ​​of each tension sensor are read to obtain the sensor measurement value T at the i-th water level. i, where i is a positive integer;

[0074] Calculate the volume of the flanged barrel-shaped composite component submerged in water at each water level.

[0075] Taking the distance between two adjacent water level heights as a segment, the flanged barrel-shaped composite component 100 has multiple interconnected segments along the Z direction, and the measured volume of each segment is Δvi = v. i+1 -v i ;

[0076] By combining the measured volume Δvi of each segment with the theoretical volume of the corresponding segment in the digital model of the flanged barrel-shaped composite part 100, the deviation between the measured thickness of each segment and the theoretical thickness in the digital model can be obtained. It should be noted that the digital model of the flanged barrel-shaped composite part 100 refers to a digital 3D model designed and drawn using 3D software before the production of the flanged barrel-shaped composite part 100. The theoretical volume of the corresponding segment can be calculated using the corresponding 3D software. When the measured volume of the corresponding segment is greater than its theoretical volume in the digital model, it indicates that the actual thickness of the corresponding segment is greater than the theoretical thickness in the digital model; conversely, when the measured volume of the corresponding segment is less than its theoretical volume in the digital model, it indicates that the actual thickness of the corresponding segment is less than the theoretical thickness in the digital model. Furthermore, we can estimate the deviation ratio between the thickness of the corresponding segment and the theoretical thickness in the digital model based on the deviation ratio between the measured volume and the theoretical volume of each segment, and thus evaluate the thickness deviation value of each segment. For the flanged barrel-shaped composite material 100 formed by the resin-based composite material in this embodiment, the number of layers of its fibrous fabric in the corresponding slit segment is defined by design, that is, the fiber content of the fibrous fabric in the corresponding slit segment is constant. The reason for the difference between the actual thickness of the slit segment and the theoretical thickness of the digital model lies in the thickness of the composite material. When the composite material in the corresponding slit segment is thicker, it indicates that the proportion of resin material in that slit segment is higher, and the Z-direction fiber volume fraction (the proportion of fibrous fabric) of that slit segment is smaller. Therefore, based on the deviation ratio between the thickness of the corresponding slit segment and the theoretical thickness of the digital model, and the theoretical Z-direction fiber volume fraction designed in the digital model, the measured Z-direction fiber volume fraction of each slit segment can be derived.

[0077] In one embodiment, the following steps are also included:

[0078] The theoretical volume ΔVt of each slit segment is measured based on the 3D digital model of the part and compared with the measured volume ΔVi of each slit segment. Since the part is manufactured according to a set fiber path, the deviation in fiber volume fraction of each slit segment is mainly caused by the part thickness, i.e., ΔVi / ΔVt = di / dt, where dt is the theoretical thickness. The average measured thickness di of each slit segment is calculated. Since the fiber volume fraction is a function of the thickness di, the fiber volume fraction f(di) corresponding to a certain thickness range is fitted by experimentally determining the fiber volume fraction at different thicknesses. Therefore, the measured fiber volume fraction ΔVt in the Z-direction of each slit segment can be obtained. fm Then, based on the measured volume fraction of fibers in the Z-direction of each slit segment, the average density Δρi of the corresponding slit segment is calculated. The total mass m of the flanged barrel-shaped composite part 100 is then calculated from the measured volume Δvi and average density Δρi of each slit segment. 估 =∑(△ρi×△vi), where m 估 The reliability of the measurement data for each segment is evaluated by comparing it with Mp. Specifically, the average density Δρi is calculated using the following formula: Δρi=V1ρ f +(1-V1)ρ r ; where ρ f ρ is the density of the fibrous material. r V1 represents the density of the resin matrix and the volume fraction of the fiber measured in the Z direction.

[0079] In one embodiment, the reliability of the measurement data for each segment is evaluated, including the following steps:

[0080] When m 估 When the value of Mp is within the preset deviation range, the measurement data of each segment is reliable;

[0081] When m 估 If the value of Mp exceeds the preset deviation range, the measurement data for each segment is unreliable. Specifically, the preset deviation range can be determined based on actual design requirements and the corresponding structural form. In this embodiment, the preset deviation range is preferably ±1%.

[0082] The following specific embodiment illustrates the provisions of this embodiment. Figure 2 The method for measuring the fiber volume fraction of the flanged barrel-shaped composite part is described below, and the specific implementation steps are as follows:

[0083] Step 1: The estimated weight of the flanged barrel-shaped composite part 100 is 150kg. Four tensile sensors with a range of 50kg are selected to measure its weight.

[0084] Step 2: Before measurement, calibrate the tension sensor within the range of 5kg to 45kg. Select a calibration range within the range of the tension sensor, and select several calibration measurement points within the calibration range. Use standard weights to measure the sensor at the corresponding calibration measurement points. The industrial control computer program is set to compensate for the measurement error of the tension sensor. The remaining measurement points within the calibration range are compensated by linear interpolation of the measurement error of the calibration points.

[0085] Step 3: Move the lifting device in the measuring fixture directly above the flanged barrel-shaped composite component 100, install the tension sensor, connect the hook of the tension sensor to the hook at the end of the traction rope, and pass one end of the traction rope through the bottom of the flanged barrel-shaped composite component and through the inside of the flanged barrel-shaped composite component. Together with the lifting ring at the other end of the traction rope, it is hoisted onto the hook below the tension sensor, thereby achieving the hoisting and fixing of the flanged barrel-shaped composite component.

[0086] Step 4: Activate the linear servo module on the lifting device to lift the flanged barrel-shaped composite part 100, read the distance value of the distance measuring sensor at each lifting point, and fine-tune it to adjust the values ​​of all distance measuring sensors to the specified values.

[0087] Step 5: Read the tension sensor values ​​at each lifting point. G1, G2, G3, and G4 are 1# 360.4N, 2# 434.1N, 3# 415.4N, and 4# 322.4N, respectively. Record these values ​​in the industrial control computer, remove the weight of the lifting rope and traction rope, and calculate the mass Mp of the flanged barrel-shaped composite part 100 as 156.11kg.

[0088] Step 6: Remove the support frame and move the annular water tank 300 below the flanged barrel-shaped composite material 100. Control the flanged barrel-shaped composite material 100 to move slowly downwards through the synchronous motion of the linear servo module until the flanged barrel-shaped composite material 100 is completely inside the annular water tank 300, with the bottom of the flanged barrel-shaped composite material 100 maintaining a certain distance from the annular water tank 300.

[0089] Step 7: Fill the annular water tank 300 with water until the water surface completely covers the upper end face of the flanged barrel-shaped composite part 100. Mark the traction rope 200 and read the tension sensor values ​​at this time: 1# 160.0N, 2# 153.1N, 3# 132.8N, 4# 118.8N. The water temperature in the annular water tank 300 is 20℃, and the corresponding density ρ of the water is... w It is 0.9982 kg / m 3 The volume V of the traction rope removed L Subsequently, the volume Vp of the flanged barrel-shaped composite part 100 was calculated to be 98.82L.

[0090] Step 8: Calculate the average bulk density ρ of the flanged barrel-shaped composite part. m It is 1.579 g / cm³ 3 The carbon fiber bulk density ρ f It is 1.787 g / cm³ 3 Resin matrix density ρ r It is 1.245 g / cm³ 3 The average fiber volume fraction V of the flanged barrel-shaped composite part 100 was calculated. fm It is 61.62%.

[0091] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for measuring the fiber volume fraction of a flanged barrel-shaped composite part, characterized in that, Includes the following steps: Tension sensors are fixedly installed on the traction ropes connected to multiple lifting points of the flanged barrel-shaped composite material, and the multiple lifting points are set on the same horizontal plane. One end of the traction rope is connected to the lifting point, and the other end of the traction rope is connected to the lifting device. The length direction of the traction rope is parallel to the Z direction of the flanged barrel-shaped composite material. The lifting device is equipped with a distance measuring sensor. The lifting device lifts the flanged barrel-shaped composite component via the traction rope, and measures and calculates the mass Mp of the flanged barrel-shaped composite component using a tension sensor; the mass Mp of the flanged barrel-shaped composite component is calculated using the following formula: ， ； Among them, G t G represents the sum of tensile forces measured by multiple tension sensors. n This represents the tension value measured by the tension sensor at the nth suspension point, where g is the acceleration due to gravity. The flanged barrel-shaped composite material is hoisted into the annular water tank, and the flanged barrel-shaped composite material is kept at a preset distance from the bottom of the annular water tank. Water is poured into the annular water tank until the water surface completely covers the top surface of the flanged barrel-shaped composite material. The buoyancy force on the flanged barrel-shaped composite material is measured by a tension sensor, and the position of the traction rope submerged in the water is marked. The volume Vp of the flanged barrel-shaped composite material is calculated based on the buoyancy force. Calculate the average density of the flanged barrel-shaped composite part. ; Based on the fiber density ρ f and resin matrix density ρ r The average fiber volume fraction V of the flanged barrel-shaped composite part was calculated. fm ; When water is poured into the annular water tank, the water pouring is paused at certain intervals after the water contacts the flanged barrel-shaped composite material. After the readings of the tension sensors stabilize, the values ​​of each tension sensor are read to obtain the sensor measurement value T at the i-th water level. i , where i is a positive integer; Calculate the volume of the flanged barrel-shaped composite material submerged in water at each water level. ; The flanged barrel-shaped composite material has multiple interconnected segments along the Z-direction, with the distance between two adjacent water level heights considered as one segment. The measured volume of each segment is Δvi = v. i+1 -v i ; The measured volume Δvi of each of the slit segments is compared with the theoretical volume of the digital model of the flanged barrel-shaped composite material in the corresponding slit segment to obtain the deviation value between the measured thickness of each slit segment and the theoretical thickness of the digital model. The theoretical volume ΔVt of each slit segment is measured based on the 3D digital model of the part and compared with the measured volume ΔVi of each slit segment. Since the part is manufactured according to the set fiber path, the deviation of the fiber volume fraction of each slit segment is mainly caused by the part thickness, i.e., ΔVi / ΔVt = di / dt, where dt is the theoretical thickness. The average measured thickness di of each slit segment is calculated. Since the fiber volume fraction is a function of the thickness di, the fiber volume fraction corresponding to a certain thickness range is obtained by fitting the fiber volume fraction at different thicknesses based on experimental measurements. This allows us to obtain the Z-axis fiber volume fraction for each segment. Then, based on the measured volume fraction of fibers in the Z-direction of each slit segment, the average density Δρi of the corresponding slit segment is calculated. The total mass m of the flanged barrel-shaped composite part is then calculated from the measured volume Δvi and the average density Δρi of each slit segment. 估 =∑(△ρi×△vi), where m 估 The reliability of the measurement data for each segment was evaluated by comparing it with Mp.

2. The method for measuring the fiber volume fraction of flanged barrel-shaped composite parts as described in claim 1, characterized in that, The volume Vp of the flanged barrel-shaped composite part is calculated using the following formula: ； Among them, G t T represents the sum of tensile forces measured by multiple tension sensors. t ρ represents the sum of tensile forces measured by multiple tensile sensors when the water surface completely submerges the top surface of the flanged barrel-shaped composite component. w This represents the density of water at the corresponding ambient temperature, g is the acceleration due to gravity, and V is the velocity. L This indicates the volume of the portion of the tow rope submerged in the water.

3. The method for measuring the fiber volume fraction of flanged barrel-shaped composite parts as described in claim 1, characterized in that, The average volume fraction of the fiber is calculated according to the following formula: 。 4. The method for measuring the fiber volume fraction of flanged barrel-shaped composite parts as described in claim 1, characterized in that, The evaluation of the reliability of the measurement data for each segment includes the following steps: When m 估 When the value of Mp is within the preset deviation range, the measurement data of each segment is reliable; When m 估 If the value of Mp exceeds the preset deviation range, the measurement data of each segment is not reliable.

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