A vertical impact test method and test device for an all-carbon aircraft seat

Abstract

The present invention relates to the technical field of composite material testing, and particularly relates to a vertical impact testing method and testing device for an all-carbon aircraft seat, including: conducting a vertical impact test on an all-carbon fiber specimen; determining whether the impact load can be used for the vertical impact test of the all-carbon aircraft seat of a target aircraft according to a failure evaluation value; conducting a multi-stage vertical impact test on the all-carbon aircraft seat specimen of the target aircraft, obtaining the strain rates of several test points on the backrest of the all-carbon aircraft seat of the target aircraft, and obtaining a strain characterization value; when it is determined that the impact of the all-carbon aircraft seat specimen of the target aircraft does not meet the preset standard according to the strain characterization value, secondarily determining whether the impact of the all-carbon aircraft seat specimen of the target aircraft meets the preset standard according to a strain offset characteristic value, or determining the reason why the impact of the all-carbon aircraft seat specimen of the target aircraft does not meet the preset standard according to the residual vibration evaluation value of the all-carbon aircraft seat specimen of the target aircraft, thereby improving the impact test accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of composite material testing, and particularly to a vertical impact testing method and testing device for an all-carbon aircraft seat. Background Art

[0002] As a core component for the safety of aircraft occupants, the structural strength and impact resistance of an aircraft seat are directly related to the survival rate of occupants in emergency situations. Especially when an aircraft makes an emergency landing or encounters turbulence, an all-carbon seat needs to withstand severe vertical impact loads.

[0003] Seats are safety components in transportation means such as automobiles, high-speed rails, and aircraft, and the contribution they can make to the lightweighting of the entire vehicle cannot be ignored.

[0004] The lightweighting and high strength of aircraft seats are the core requirements for aviation safety and energy efficiency improvement. Although traditional metal materials such as aluminum alloys have good ductility, their density is relatively high, making it difficult to meet the weight reduction requirements of modern aircraft. All-carbon fiber composite materials, with their high specific strength (strength / density) and customizable ply design, have become the preferred materials for the structural upgrade of aircraft seats. However, their anisotropy and delamination sensitivity need to be strictly verified through impact testing methods to achieve the preparation of safer all-carbon aircraft seats.

[0005] Chinese Patent Publication No.: CN102564876A discloses a vertical impact testing device and testing method for an all-carbon seat. The testing device includes a test bench, a mounting bracket, an impact component, and a lifting mechanism, where: the test bench includes a base and a support fixed on the base, and the support bears the test seat; the mounting bracket includes left and right columns and a cross beam erected at the top ends of the left and right columns; the left and right columns are fixed on the base; the impact component is lifted by the lifting mechanism to a preset suspension height in the first state and freely released in the second state to impact the test part of the test seat. The testing method repeats lifting the impact component to the preset height and then freely dropping it to impact the test part of the test seat. If the test seat is deformed or cracked within the preset number of impacts, it is determined to pass the test; otherwise, it is determined not to pass the test. In the present invention, the impact component freely drops from the suspended state, thereby applying a vertical impact load to the test part of the seat. After repeating the test multiple times, the vertical strength of the seat can be tested.

[0006] It can be seen that in the above technical solution, the anisotropic characteristics of carbon fiber composite materials are not considered, and a general specimen is directly used for impact testing without simulating the actual ply structure at the connection between the seat back and the seat cushion. Only whether it is cracked is used as the passing standard, lacking the analysis of strain rate and residual vibration characteristics, resulting in the inability to detect internal damage or structural looseness, thus leading to the problem of low accuracy of impact testing. Summary of the Invention

[0007] To this end, the present invention provides a method and a testing device for vertical impact testing of an all-carbon aircraft seat, so as to overcome the problems in the prior art that the anisotropic characteristics of carbon fiber composites are not considered, a general specimen is directly used for impact testing, the actual ply structure at the connection between the seat back and the seat cushion is not simulated, and only whether it breaks is used as the passing standard, lacking the analysis of strain rate and residual vibration characteristics, resulting in the inability to detect internal damage or structural looseness, thereby leading to low accuracy of the impact test.

[0008] To achieve the above object, on the one hand, the present invention provides a method for vertical impact testing of an all-carbon aircraft seat, including:

[0009] Conduct a vertical impact test on an all-carbon fiber specimen, record the impact load and obtain the delamination area of the all-carbon fiber specimen after being subjected to the impact load, and obtain a failure evaluation value;

[0010] Determine whether the impact load can be used for the vertical impact testing of the all-carbon aircraft seat of the target aircraft according to the failure evaluation value;

[0011] Conduct a multi-stage vertical impact test on the all-carbon aircraft seat specimen of the target aircraft, obtain the strain rates of several test points on the backrest of the all-carbon aircraft seat of the target aircraft, and obtain a strain characterization value, wherein the ultimate impact load in the multi-stage vertical impact is the impact load that can be used for the vertical impact testing of the all-carbon aircraft seat of the target aircraft;

[0012] When it is determined according to the strain characterization value that the impact of the all-carbon aircraft seat specimen of the target aircraft does not meet the preset standard, obtain the average strain rate to obtain a strain deviation characteristic value and obtain the vibration duration of the all-carbon aircraft seat specimen of the target aircraft after the impact to obtain a residual vibration evaluation value;

[0013] When it is determined according to the strain characterization value that the impact of the all-carbon aircraft seat specimen of the target aircraft does not meet the preset standard, re-determine whether the impact of the all-carbon aircraft seat specimen of the target aircraft meets the preset standard according to the strain deviation characteristic value, or determine the reason why the impact of the all-carbon aircraft seat specimen of the target aircraft does not meet the preset standard according to the residual vibration evaluation value of the all-carbon aircraft seat specimen of the target aircraft, wherein the reasons include structural looseness of the all-carbon aircraft seat specimen of the target aircraft and internal damage of the all-carbon material of the all-carbon aircraft seat specimen of the target aircraft.

[0014] Further, the all-carbon fiber specimen is a rectangular specimen with a preset thickness, wherein the ply angle, number of plies, and thickness of the all-carbon fiber specimen are respectively the same as the ply angle, number of plies, and thickness at the connection between the backrest and the seat cushion of the all-carbon aircraft seat of the target aircraft; the all-carbon aircraft seat specimen of the target aircraft simulates the structure of the all-carbon aircraft seat of the target aircraft through a hot pressing forming process.

[0015] Further, the process of the multi-stage vertical impact includes:

[0016] In the transient impact stage, a half-sine pulse load is applied to several uniformly distributed test points on the backrest of the all-carbon seat sample of the target aircraft at a preset acceleration and for a first preset duration;

[0017] In the continuous loading stage, an ultimate impact load is applied for a second preset duration after the transient impact.

[0018] Further, it is determined whether the impact load can be used for the target vertical impact test according to the failure evaluation value, where,

[0019] If the failure evaluation value is less than the preset failure evaluation value, it is determined that the impact load can be used for the target vertical impact test;

[0020] If the failure evaluation value is greater than or equal to the preset failure evaluation value, it is determined that the impact load cannot be used for the target vertical impact test;

[0021] The failure evaluation value is the ratio between the delamination area of the all-carbon fiber sample and the total area of the all-carbon fiber sample.

[0022] Further, the process of determining that the impact of the all-carbon seat sample of the target aircraft does not meet the preset standard according to the strain characterization value includes:

[0023] Comparing the strain characterization value with a first preset strain characterization value and a second preset strain characterization value respectively;

[0024] If the strain characterization value is greater than or equal to the first preset strain characterization value and less than the second preset strain characterization value, it is determined that the impact of the all-carbon seat sample of the target aircraft does not meet the preset standard and the remanufactured all-carbon seat sample of the target aircraft is re-determined according to the strain offset characteristic value whether the impact of the all-carbon seat sample of the target aircraft meets the preset standard;

[0025] If the strain characterization value is greater than or equal to the second preset strain characterization value, it is determined that the impact of the all-carbon seat sample of the target aircraft does not meet the preset standard and the reason why the impact of the all-carbon seat sample of the target aircraft does not meet the preset standard is determined according to the residual vibration evaluation value of the all-carbon seat sample of the target aircraft;

[0026] The strain characterization value is the ratio between the average strain rate and the preset strain rate.

[0027] Further, it is re-determined whether the impact of the all-carbon seat sample of the target aircraft meets the preset standard according to the strain offset characteristic value, where,

[0028] If the strain offset characteristic value is less than the preset strain offset characteristic value, it is determined that the impact of the all-carbon seat sample of the target aircraft meets the preset standard;

[0029] If the strain offset eigenvalue is greater than or equal to the preset strain offset eigenvalue, it is determined that the impact of the all-carbon seat sample of the target aircraft does not meet the preset standard, and the ultimate impact load is reduced according to the difference between the strain offset eigenvalue and the preset strain offset eigenvalue;

[0030] The strain offset eigenvalue is the ratio of the number of measurement points with a strain rate exceeding the preset strain rate to the total number of measurement points.

[0031] Furthermore, there are several load reduction methods for reducing the ultimate impact load, and each reduction method has a different reduction amplitude for the ultimate impact load.

[0032] Furthermore, according to the residual vibration evaluation value of the all-carbon seat sample of the target aircraft, the reason for the non-compliance of the impact of the all-carbon seat sample of the target aircraft with the preset standard is determined, where

[0033] If the residual vibration evaluation value is less than the preset residual vibration evaluation value, it is determined that the reason for the non-compliance of the impact of the all-carbon seat sample of the target aircraft with the preset standard is the structural looseness of the all-carbon seat sample of the target aircraft;

[0034] If the residual vibration evaluation value is greater than or equal to the preset residual vibration evaluation value, it is determined that the reason for the non-compliance of the impact of the all-carbon seat sample of the target aircraft with the preset standard is the internal damage of the all-carbon material of the all-carbon seat sample of the target aircraft.

[0035] Furthermore, the residual vibration evaluation value is the ratio of the vibration duration of the all-carbon seat sample of the target aircraft after impact to the preset duration.

[0036] On the other hand, the present invention provides a test device applicable to the vertical impact test method of an aircraft all-carbon seat, including: a base, an adjustable fixture disposed above the base for fixing a full carbon fiber sample or an all-carbon seat sample of a target aircraft, a mounting frame connected to the base through a first column and a second column of the mounting frame, and a pendulum connected to the top rod of the mounting frame through a pendulum shaft;

[0037] A data acquisition module, including a load acquisition unit for acquiring an impact load, an area acquisition unit for acquiring the delamination area of the full carbon fiber sample, a strain rate acquisition unit for acquiring the backrest strain rate, and a duration acquisition unit for acquiring the all-carbon seat sample of the target aircraft;

[0038] A control module, which is connected to the data acquisition module, and is used to determine whether the impact load can be used for the vertical impact test of the all-carbon seat of the target aircraft according to the failure evaluation value; and is used to determine whether the impact of the all-carbon seat sample of the target aircraft meets the preset standard according to the strain characterization value.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows. By constructing a material-level equivalent test system, the present invention significantly improves the accuracy of impact tests. A fully carbon fiber rectangular specimen with the same ply angles, number of layers, and thickness as the connection between the backrest and the seat cushion of the target aircraft's all-carbon seat is used to accurately reproduce the anisotropic characteristics of carbon fiber composites, avoiding test deviations caused by differences between general specimens and actual structures, thereby providing a reliable material failure benchmark for impact load calibration.

[0040] Furthermore, in the present invention, a semi-sine pulse load is applied during the transient impact stage to simulate the initial impact of an emergency landing, and the ultimate impact load is maintained during the continuous loading stage to reproduce subsequent overloads, fully covering the dynamic response process of the all-carbon seat under vertical impact, thereby solving the defect that traditional single-pulse tests cannot restore the action of composite loads.

[0041] Furthermore, the present invention quantifies the degree of dynamic overload by introducing the ratio of the average strain rate to a preset threshold, i.e., the strain characterization value, and combines the ratio of the vibration duration to a preset duration, i.e., the residual vibration evaluation value, to analyze the structural integrity, which can not only identify local overload risks but also distinguish between structural looseness and internal material damage, thus breaking through the limitation of only using fracture deformation as the standard.

[0042] Furthermore, the present invention uses the ratio of the delaminated area of the fully carbon fiber specimen to the total area as the failure evaluation value to establish the correlation between material failure and structural testing, ensuring the matching of the ultimate impact load and the bearing capacity of the target all-carbon seat, avoiding test overload or insufficiency, and thus improving the credibility of test results.

[0043] Furthermore, based on the ratio of the average strain rate to a preset value and the strain offset characteristic value, accurate positioning of the local overload area and dynamic adjustment of the load are achieved, avoiding the coarseness of overall strain evaluation in traditional methods, and thus improving the test accuracy.

[0044] Furthermore, the present invention is provided with several load reduction methods for reducing the ultimate impact load, and each reduction method has a different reduction amplitude for the ultimate impact load, thereby achieving precise control of the reduction amplitude of the ultimate impact load. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a flowchart of the vertical impact test method for the all-carbon seat of the aircraft in the embodiment of the present invention;

[0046] Figure 2 It is a flowchart of determining whether the impact load can be used for the target vertical impact test in the embodiment of the present invention;

[0047] Figure 3 It is a flowchart of determining whether the impact test method meets the preset standard according to the strain characterization value in the embodiment of the present invention;

[0048] Figure 4 A flowchart for determining the reason why the impact test method does not meet the preset standard in the embodiment of the present invention;

[0049] Figure 5 A structural schematic diagram of a vertical impact test device for an all-carbon aircraft seat in the embodiment of the present invention;

[0050] In the figure, 1 is the base; 2 is the adjustable fixture; 3 is the first column; 4 is the second column; 5 is the ejector rod; 6 is the swing shaft; 7 is the pendulum bob. Detailed implementation manners

[0051] In order to make the objectives and advantages of the present invention clearer, the present invention will be further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0052] The preferred implementation manners of the present invention will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these implementation manners are only used to explain the technical principle of the present invention and do not limit the protection scope of the present invention.

[0053] Please refer to Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 and Figure 5 as shown, which are respectively a flowchart of a vertical impact test method for an all-carbon aircraft seat in the embodiment of the present invention; a flowchart of determining whether an impact load can be used for a target vertical impact test in the embodiment of the present invention; a flowchart of determining whether an impact test method meets the preset standard according to a strain characterization value in the embodiment of the present invention; a flowchart of determining the reason why the impact test method does not meet the preset standard in the embodiment of the present invention; a structural schematic diagram of a vertical impact test device for an all-carbon aircraft seat in the embodiment of the present invention.

[0054] On the one hand, an embodiment of the present invention provides a vertical impact test method for an all-carbon aircraft seat, including:

[0055] Step S1: Conduct a vertical impact test on a full-carbon fiber specimen, record the impact load, obtain the delamination area of the full-carbon fiber specimen after being subjected to the impact load, and calculate the failure evaluation value;

[0056] Step S2: Determine whether the impact load can be used for the target vertical impact test of the all-carbon aircraft seat according to the failure evaluation value;

[0057] Step S3: Conduct a multi-stage vertical impact test on the target all-carbon aircraft seat specimen, obtain the strain rates of several test points on the backrest of the target all-carbon aircraft seat, and calculate the strain characterization value, where the ultimate impact load in the multi-stage vertical impact is the impact load that can be used for the target vertical impact test of the all-carbon aircraft seat;

[0058] In step S4, when it is determined that the impact of the target aircraft all-carbon seat sample does not meet the preset standard according to the strain characterization value, obtain the average strain rate to obtain the strain offset characteristic value, and obtain the residual vibration evaluation value by calculating the vibration duration of the target aircraft all-carbon seat sample after impact;

[0059] In step S5, when it is determined that the impact of the target aircraft all-carbon seat sample does not meet the preset standard according to the strain characterization value, re-determine whether the impact of the target aircraft all-carbon seat sample meets the preset standard according to the strain offset characteristic value, or determine the reason why the impact of the target aircraft all-carbon seat sample does not meet the preset standard according to the residual vibration evaluation value of the target aircraft all-carbon seat sample. The reasons include the structural looseness of the target aircraft all-carbon seat sample and the internal damage of the all-carbon material of the target aircraft all-carbon seat sample.

[0060] In this embodiment, the strain rates of several test points on the backrest of the target aircraft all-carbon seat in step S3 are obtained by a number of fiber Bragg grating sensors provided in the backrest and corresponding to the test points one by one with a sampling rate of 100 kHz.

[0061] Specifically, the all-carbon fiber sample is a rectangular sample with a preset length of 300 mm and a preset width of 150 mm. The ply angle, number of plies, and thickness of the all-carbon fiber sample are the same as those of the connection between the backrest and the seat cushion of the target aircraft all-carbon seat respectively; the target aircraft all-carbon seat sample simulates the structure of the target aircraft all-carbon seat through a hot pressing process.

[0062] Specifically, in step S1, an impact test is performed on the all-carbon fiber sample using a pendulum type vertical impact testing machine, and a load sensor is used to record the impact load. The load sensor is embedded inside the pendulum. The load sensor can be a piezoelectric sensor or a strain gauge sensor, and there is no specific limitation as long as it can meet the impact load recording requirements.

[0063] Specifically, the process of the multi-stage vertical impact includes:

[0064] The transient impact stage applies a half-sine pulse load to a number of test points evenly distributed on the backrest of the target aircraft all-carbon seat sample with a preset acceleration of 50g and a first preset duration of 10 ms;

[0065] The continuous loading stage applies a limit impact load that maintains for a second preset duration of 100 ms after the transient impact.

[0066] Specifically, determine whether the impact load can be used for the target vertical impact test according to the failure evaluation value, where

[0067] If the failure evaluation value is less than 7.5% of the preset failure evaluation value, it is determined that the impact load can be used for the target vertical impact test;

[0068] If the failure evaluation value is greater than or equal to the preset failure evaluation value, it is determined that the impact load cannot be used for the target vertical impact test;

[0069] The failure evaluation value is the ratio between the delamination area of the all-carbon fiber specimen and the total area of the all-carbon fiber specimen. Among them, ultrasonic CT scanning is used to detect the delamination damage generated inside the carbon fiber composite material due to impact to obtain the delamination area. The delamination area refers to the two-dimensional projected area of the damage area formed by the debonding, that is, delamination, of the interlayer interface of the composite laminate after being subjected to the impact load.

[0070] The failure evaluation value quantifies the severity of delamination damage, and the damage tolerance of the all-carbon fiber composite material under the impact load is judged through the failure evaluation value.

[0071] In this embodiment, the preset failure evaluation value is selected as 7.5%. However, the above value is not limited to this, and those skilled in the art can also adjust this value according to actual needs.

[0072] Specifically, the process of determining whether the impact of the target aircraft all-carbon seat specimen meets the preset standard according to the strain characterization value includes:

[0073] Compare the strain characterization value with the first preset strain characterization value 0.98 and the second preset strain characterization value 1.35 respectively;

[0074] If the strain characterization value is less than the first preset strain characterization value, it is determined that the impact of the target aircraft all-carbon seat specimen meets the preset standard;

[0075] If the strain characterization value is greater than or equal to the first preset strain characterization value and less than the second preset strain characterization value, it is determined that the impact of the target aircraft all-carbon seat specimen does not meet the preset standard, and the re-prepared target aircraft all-carbon seat specimen is secondarily determined whether the impact meets the preset standard according to the strain offset characteristic value;

[0076] If the strain characterization value is greater than or equal to the second preset strain characterization value, it is determined that the impact of the target aircraft all-carbon seat specimen does not meet the preset standard, and the reason for the non-compliance of the impact of the target aircraft all-carbon seat specimen is determined according to the residual vibration evaluation value of the target aircraft all-carbon seat specimen;

[0077] The strain characterization value is the ratio between the average strain rate and the preset strain rate of 1200 με / s, where the average strain rate is the average of the strain rates of several test points evenly distributed on the backrest of the all-carbon seat sample of the target aircraft.

[0078] In this embodiment, the value range of the first preset strain characterization value is (0.75, 1.00), and the value range of the second preset strain characterization value is (1.15, 1.55). Preferably, the first preset strain characterization value is selected as 0.98, and the second preset strain characterization value is selected as 1.35.

[0079] Specifically, according to the strain offset characteristic value, it is determined secondarily whether the impact of the all-carbon seat sample of the target aircraft meets the preset standard, where

[0080] If the strain offset characteristic value is less than the preset strain offset characteristic value of 0.25, it is determined that the impact of the all-carbon seat sample of the target aircraft meets the preset standard;

[0081] If the strain offset characteristic value is greater than or equal to the preset strain offset characteristic value, it is determined that the impact of the all-carbon seat sample of the target aircraft does not meet the preset standard, and the ultimate impact load is reduced according to the difference between the strain offset characteristic value and the preset strain offset characteristic value;

[0082] The strain offset characteristic value is the ratio between the number of measurement points where the strain rate exceeds the preset strain rate of 1200 με / s and the total number of measurement points.

[0083] In this embodiment, the preset strain offset characteristic value is taken as 0.25, and the value of the preset strain offset characteristic value is adjusted by those skilled in the art according to the requirements of the detection and evaluation accuracy of the impact resistance performance of the all-carbon seat. The higher the requirement for the detection and evaluation accuracy, the smaller the value of the preset strain offset characteristic value. Preferably, the value range of the preset strain offset characteristic value can be (0.10, 0.40).

[0084] Specifically, several load reduction methods are set for the reduction of the ultimate impact load, where

[0085] If the strain offset difference is less than the first preset strain offset difference of 0.08, the first load adjustment coefficient of 0.98 is used to reduce the ultimate impact load to the corresponding value;

[0086] If the strain offset difference is greater than or equal to the first preset strain offset difference and less than the second preset strain offset difference of 0.19, the second load adjustment coefficient of 0.96 is used to reduce the ultimate impact load to the corresponding value;

[0087] If the strain offset difference is greater than or equal to the second preset strain offset difference, the third load adjustment factor 0.94 is used to reduce the ultimate impact load to the corresponding value;

[0088] The strain offset difference is the difference between the strain offset characteristic value and the preset strain offset characteristic value.

[0089] Specifically, the reason why the impact of the target aircraft all-carbon seat sample does not meet the preset standard is determined according to the residual vibration evaluation value of the target aircraft all-carbon seat sample, where

[0090] If the residual vibration evaluation value is less than the preset residual vibration evaluation value of 0.33, it is determined that the reason why the impact of the target aircraft all-carbon seat sample does not meet the preset standard is the structural looseness of the target aircraft all-carbon seat sample;

[0091] If the residual vibration evaluation value is greater than or equal to the preset residual vibration evaluation value, it is determined that the reason why the impact of the target aircraft all-carbon seat sample does not meet the preset standard is the internal damage of the all-carbon material of the target aircraft all-carbon seat sample.

[0092] Specifically, the residual vibration evaluation value is the ratio of the vibration duration of the target aircraft all-carbon seat sample after impact to the preset duration of 5S.

[0093] In this embodiment, the vibration duration of the target aircraft all-carbon seat sample after impact is obtained by an acceleration sensor arranged at the center point of the backrest.

[0094] In this embodiment, the preset residual vibration evaluation value is selected as 0.33, but the above value is not limited to this, and those skilled in the art can also adjust this value according to actual needs.

[0095] On the other hand, the present invention provides a test device applicable to the vertical impact test method of an aircraft all-carbon seat, including: a base 1, an adjustable fixture 2 arranged above the base 1 for fixing a full carbon fiber sample or a target aircraft all-carbon seat sample, an installation frame connected to the base 1 through a first column 3 and a second column 4 of the installation frame, and a pendulum 7 connected to the top rod 5 of the installation frame through a pendulum shaft 6;

[0096] A data acquisition module, including a load acquisition unit for acquiring an impact load, an area acquisition unit for acquiring the delamination area of the full carbon fiber sample, a strain rate acquisition unit for acquiring the backrest strain rate of the target aircraft all-carbon seat sample, and a duration acquisition unit for acquiring the target aircraft all-carbon seat sample;

[0097] A control module, which is connected to the data acquisition module, is configured to determine whether the impact load can be used for the vertical impact test of the all-carbon seat of the target aircraft according to the failure evaluation value; and is configured to determine whether the impact on the all-carbon seat specimen of the target aircraft meets the preset standard according to the strain characterization value.

[0098] Specifically, the clamping surface of the adjustable fixture is covered with a silica gel pad, which is used to avoid pinching the specimen.

[0099] So far, the technical solution of the present invention has been described in combination with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of the present invention.

Claims

1. A vertical impact test method for an all-carbon aircraft seat, characterized in that, Including: Performing a vertical impact test on a full carbon fiber specimen, recording the impact load, obtaining the delamination area of the full carbon fiber specimen after being subjected to the impact load, and obtaining a failure evaluation value; Determining whether the impact load can be used for the vertical impact test of the full carbon seat of the target aircraft according to the failure evaluation value; Performing a multi-stage vertical impact test on the full carbon seat specimen of the target aircraft, obtaining the strain rates of several test points on the backrest of the full carbon seat of the target aircraft, and obtaining a strain characterization value, wherein the ultimate impact load in the multi-stage vertical impact test is the impact load that can be used for the vertical impact test of the full carbon seat of the target aircraft; When it is determined according to the strain characterization value that the impact of the full carbon seat specimen of the target aircraft does not meet the preset standard, obtaining the average strain rate to obtain a strain offset characteristic value and the vibration duration of the full carbon seat specimen of the target aircraft after impact to obtain a residual vibration evaluation value; When it is determined according to the strain characterization value that the impact of the full carbon seat specimen of the target aircraft does not meet the preset standard, secondarily determining whether the impact of the full carbon seat specimen of the target aircraft meets the preset standard according to the strain offset characteristic value, or determining the reason why the impact of the full carbon seat specimen of the target aircraft does not meet the preset standard according to the residual vibration evaluation value of the full carbon seat specimen of the target aircraft, wherein the reasons include the structural looseness of the full carbon seat specimen of the target aircraft and the internal damage of the full carbon material of the full carbon seat specimen of the target aircraft.

2. The vertical impact test method for the all-carbon aircraft seat according to claim 1, wherein The full carbon fiber specimen is a rectangular specimen with a preset thickness, wherein the ply angle, number of plies, and thickness of the full carbon fiber specimen are respectively the same as the ply angle, number of plies, and thickness at the connection between the backrest and the seat cushion of the full carbon seat of the target aircraft; the full carbon seat specimen of the target aircraft simulates the structure of the full carbon seat of the target aircraft through a hot pressing process.

3. The vertical impact test method for the all-carbon aircraft seat according to claim 2, characterized in that, The process of the multi-stage vertical impact includes: A transient impact stage, in which a half-sine pulse load is applied to several test points evenly distributed on the backrest of the full carbon seat specimen of the target aircraft at a preset acceleration and a first preset duration; A continuous loading stage, in which an ultimate impact load is applied for a second preset duration after the transient impact.

4. The vertical impact test method for the all-carbon aircraft seat according to claim 3, characterized in that, Determining whether the impact load can be used for the target vertical impact test according to the failure evaluation value, wherein If the failure evaluation value is less than the preset failure evaluation value, it is determined that the impact load can be used for the target vertical impact test; If the failure evaluation value is greater than or equal to the preset failure evaluation value, it is determined that the impact load cannot be used for the target vertical impact test; The failure evaluation value is the ratio between the delamination area of the full carbon fiber specimen and the total area of the full carbon fiber specimen.

5. The vertical impact test method for the all-carbon aircraft seat according to claim 4, characterized in that, The process of determining that the impact of the full carbon seat specimen of the target aircraft does not meet the preset standard according to the strain characterization value includes: Comparing the strain characterization value with a first preset strain characterization value and a second preset strain characterization value respectively; If the strain characterization value is greater than or equal to the first preset strain characterization value and less than the second preset strain characterization value, it is determined that the impact of the target aircraft all-carbon seat sample does not meet the preset standard, and the re-prepared target aircraft all-carbon seat sample is used to re-determine whether the impact method of the target aircraft all-carbon seat sample meets the preset standard according to the strain offset characteristic value; If the strain characterization value is greater than or equal to the second preset strain characterization value, it is determined that the impact of the target aircraft all-carbon seat sample does not meet the preset standard, and the reason why the impact of the target aircraft all-carbon seat sample does not meet the preset standard is determined according to the residual vibration evaluation value of the target aircraft all-carbon seat sample; The strain characterization value is the ratio between the average strain rate and the preset strain rate.

6. The vertical impact test method for the all-carbon aircraft seat according to claim 5, characterized in that, Re-determine whether the impact of the target aircraft all-carbon seat sample meets the preset standard according to the strain offset characteristic value, where If the strain offset characteristic value is less than the preset strain offset characteristic value, it is determined that the impact of the target aircraft all-carbon seat sample meets the preset standard; If the strain offset characteristic value is greater than or equal to the preset strain offset characteristic value, it is determined that the impact of the target aircraft all-carbon seat sample does not meet the preset standard, and the ultimate impact load is reduced according to the difference between the strain offset characteristic value and the preset strain offset characteristic value; The strain offset characteristic value is the ratio between the number of measurement points where the strain rate exceeds the preset strain rate and the total number of measurement points.

7. The vertical impact test method for the all-carbon aircraft seat according to claim 6, characterized in that There are several load reduction methods for reducing the ultimate impact load, and each reduction method has a different reduction amplitude for the ultimate impact load.

8. The vertical impact test method for the all-carbon aircraft seat according to claim 7, characterized in that Determine the reason why the impact of the target aircraft all-carbon seat sample does not meet the preset standard according to the residual vibration evaluation value of the target aircraft all-carbon seat sample, where If the residual vibration evaluation value is less than the preset residual vibration evaluation value, it is determined that the reason why the impact of the target aircraft all-carbon seat sample does not meet the preset standard is that the structure of the target aircraft all-carbon seat sample is loose; If the residual vibration evaluation value is greater than or equal to the preset residual vibration evaluation value, it is determined that the reason why the impact of the target aircraft all-carbon seat sample does not meet the preset standard is internal damage to the all-carbon material of the target aircraft all-carbon seat sample.

9. The vertical impact test method for the all-carbon aircraft seat according to claim 8, characterized in that The residual vibration evaluation value is the ratio between the vibration duration of the target aircraft all-carbon seat sample after impact and the preset duration.

10. A test device applicable to the aircraft all-carbon seat vertical impact test method according to any one of claims 1-9, characterized in that, Including: A base, an adjustable fixture arranged above the base for fixing the all-carbon fiber sample or the target aircraft all-carbon seat sample, the mounting frame is connected to the base through the first upright column and the second upright column of the mounting frame, and the pendulum is connected to the top rod of the mounting frame through a pendulum shaft; A data acquisition module, including a load acquisition unit for acquiring the impact load, an area acquisition unit for acquiring the delamination area of the all-carbon fiber sample, a strain rate acquisition unit for acquiring the backrest strain rate of the target aircraft all-carbon seat sample, and a duration acquisition unit for acquiring the target aircraft all-carbon seat sample; A control module, which is connected to the data acquisition module, is used to determine whether the impact load can be used for the vertical impact test of the all-carbon seat of the target aircraft according to the failure evaluation value; and is used to determine whether the impact on the all-carbon seat specimen of the target aircraft meets the preset standard according to the strain characterization value.

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