A method and device for predicting the performance of a glued riveted joint

Abstract

The application discloses a kind of glue riveting joint performance prediction method and device, obtain the double hump tensile curve of the glue riveting joint to be measured after tensile test to the glue riveting joint to be measured, and based on the abscissa and ordinate of the first hump coordinate value of double hump tensile curve, that is, the glue joint failure tensile displacement and glue joint failure load when the glue riveting joint to be measured starts to fail, the glue joint performance of glue riveting joint to be measured is predicted;Based on the abscissa and ordinate of the second hump coordinate value of double hump tensile curve, that is, the riveting failure tensile displacement and riveting failure load when the glue riveting joint to be measured starts to fail, the riveting performance of glue riveting joint to be measured is predicted.It can be specifically analyzed by double hump tensile curve respectively when glue riveting joint to be measured glue joint failure and riveting failure respectively, to determine the performance of glue joint and riveting respectively, so as to adjust glue joint mode and riveting mode respectively, improve the connection stability of glue riveting joint to be measured.

Description

Technical Field

[0001] This invention relates to the field of metal material performance testing technology, and in particular to a method and apparatus for predicting the performance of adhesive riveting joints. Background Technology

[0002] Adhesive-fitted joints are manufactured using a composite joining technology that combines adhesive bonding and riveting. By using adhesives and rivets together, a stronger and more reliable connection is formed. The principle is based on the chemical reaction or physical solidification between the adhesive and the base material, along with the mechanical locking effect of the rivets, to achieve the connection of the materials. Adhesive-fitted joints are widely used in the automotive, aerospace, home appliance, and construction industries due to their strong adhesion, good sealing performance, strong corrosion resistance, ability to connect dissimilar materials, and good seismic performance.

[0003] In the existing technology, quasi-static tensile failure tests are usually performed on the glued riveting joints to predict the performance of the glued riveting joints based on the final failure state of the glued riveting joints. However, this method cannot fully evaluate the comprehensive performance of the glued riveting joints after the superposition of glue bonding and riveting. Summary of the Invention

[0004] The purpose of this invention is to provide a method and apparatus for predicting the performance of adhesive riveting joints. Specifically, it can analyze the adhesive failure and riveting failure of the tested adhesive riveting joints separately using a double-hump tensile curve, thereby determining the performance of the adhesive bonding and riveting respectively. This allows for targeted adjustments to the adhesive bonding method and the riveting method to improve the connection stability of the tested adhesive riveting joints.

[0005] To address the aforementioned technical problems, this invention provides a method for predicting the performance of adhesive-fitted joints, comprising:

[0006] A tensile test is performed on the rivet joint to obtain the double-hump tensile curve of the rivet joint. The horizontal axis of the double-hump tensile curve is the tensile displacement, and the vertical axis is the load of the rivet joint under tension.

[0007] The bonding performance of the tested adhesive riveting joint is predicted based on the first hump coordinate value of the double-hump tensile curve. The horizontal axis of the first hump coordinate value is the bonding failure tensile displacement when the tested adhesive riveting joint begins to fail, and the vertical axis is the bonding failure load when the tested adhesive riveting joint begins to fail. The bonding performance of the tested adhesive riveting joint is positively correlated with the bonding failure tensile displacement and the bonding failure load.

[0008] The riveting performance of the tested adhesive riveting joint is predicted based on the second hump coordinate value of the double-hump tensile curve. The horizontal axis of the second hump coordinate value is the riveting failure tensile displacement when the tested adhesive riveting joint begins to fail, and the vertical axis is the riveting failure load when the tested adhesive riveting joint begins to fail. The riveting performance of the tested adhesive riveting joint is positively correlated with the riveting failure tensile displacement and the riveting failure load.

[0009] Preferably, the bonding performance of the tested adhesive riveting joint is predicted based on the first hump coordinate value of the double-hump tensile curve, wherein the abscissa of the first hump coordinate value is the bonding failure tensile displacement when the tested adhesive riveting joint begins to fail, and the ordinate is the bonding failure load when the tested adhesive riveting joint begins to fail; the bonding performance of the tested adhesive riveting joint is positively correlated with the bonding failure tensile displacement and the bonding failure load, including:

[0010] Based on the abscissa and ordinate of the first hump coordinate value of the double-hump tensile curve, the tensile displacement of the adhesive joint failure and the adhesive joint failure load at the point when the tested adhesive joint begins to fail are determined respectively.

[0011] If the tensile displacement of the adhesive failure is not less than the preset minimum adhesive failure displacement, and the adhesive failure load is not less than the minimum adhesive failure load, then the adhesive performance of the tested adhesive riveting joint is determined to meet the preset adhesive performance requirements.

[0012] If the tensile displacement of the adhesive failure is less than the preset minimum adhesive failure displacement, and / or the adhesive failure load is less than the minimum adhesive failure load, then it is determined that the adhesive performance of the tested adhesive riveting joint does not meet the preset adhesive performance requirements.

[0013] Preferably, if the adhesive failure tensile displacement is less than the preset minimum adhesive failure displacement, and / or the adhesive failure load is less than the minimum adhesive failure load, then it is determined that the adhesive performance of the tested adhesive riveting joint does not meet the preset adhesive performance requirements, including:

[0014] If the tensile displacement of the adhesive failure is less than the minimum adhesive failure displacement, but the adhesive failure load is not less than the minimum adhesive failure load, then the adhesive performance of the tested adhesive joint is determined to be insufficient.

[0015] If the tensile displacement of the adhesive failure is not less than the minimum adhesive failure displacement, but the adhesive failure load is less than the minimum adhesive failure load, then the adhesive performance of the tested adhesive joint is determined to be insufficient adhesive layer bonding strength.

[0016] If the tensile displacement of the adhesive failure is less than the minimum adhesive failure displacement, and the adhesive failure load is less than the minimum adhesive failure load, then the adhesive performance of the tested adhesive riveting joint is determined to be insufficient adhesive performance and insufficient adhesive layer bonding strength.

[0017] Preferably, after performing a tensile test on the adhesive riveting joint to obtain a double-hump tensile curve of the joint, wherein the horizontal axis of the double-hump tensile curve represents the tensile displacement and the vertical axis represents the load on the joint under tension, the test further includes:

[0018] The peak slope of the adhesive failure of the tested adhesive riveting joint is determined based on the adhesive failure tensile displacement and the adhesive failure load.

[0019] The adhesive stiffness of the tested adhesive riveting joint is determined based on the slope of the adhesive failure peak value, and the adhesive stiffness is positively correlated with the slope of the adhesive failure peak value.

[0020] Preferably, the riveting performance of the tested adhesive riveting joint is predicted based on the second hump coordinate value of the double-hump tensile curve, wherein the abscissa of the second hump coordinate value is the riveting failure tensile displacement when the tested adhesive riveting joint begins to fail, and the ordinate is the riveting failure load when the tested adhesive riveting joint begins to fail; the riveting performance of the tested adhesive riveting joint is positively correlated with the riveting failure tensile displacement and the riveting failure load, including:

[0021] Based on the abscissa and ordinate of the second hump coordinate value of the double-hump tensile curve, the riveting failure tensile displacement and the riveting failure load at the point when the tested adhesive riveting joint begins to fail are determined respectively.

[0022] If the tensile displacement of the riveting failure is not less than the preset minimum riveting failure displacement, and the load of the riveting failure is not less than the minimum load of the riveting failure, then the riveting performance of the tested adhesive riveting joint is determined to meet the preset riveting performance requirements.

[0023] If the tensile displacement of the riveting failure is less than the preset minimum riveting failure displacement, and / or the riveting failure load is less than the minimum riveting failure load, then it is determined that the riveting performance of the tested adhesive riveting joint does not meet the preset riveting performance requirements.

[0024] Preferably, if the riveting failure tensile displacement is less than the preset minimum riveting failure displacement, and / or the riveting failure load is less than the minimum riveting failure load, then it is determined that the riveting performance of the tested adhesive riveting joint does not meet the preset riveting performance requirements, including:

[0025] If the tensile displacement of the riveting failure is less than the minimum riveting failure displacement, but the load of the riveting failure is not less than the minimum riveting failure load, then the riveting performance of the tested adhesive riveting joint is determined to be insufficient for either the rivet or the material being connected.

[0026] If the tensile displacement of the riveting failure is not less than the minimum riveting failure displacement, but the riveting failure load is less than the minimum riveting failure load, then the riveting performance of the tested adhesive riveting joint is determined to be insufficient rivet clamping.

[0027] If the tensile displacement of the riveting failure is less than the minimum riveting failure displacement, and the load of the riveting failure is less than the minimum riveting failure load, then the riveting performance of the tested adhesive riveting joint is determined to be that the rivet or the material being connected is inadequate and the rivet is not properly clamped.

[0028] Preferably, after performing a tensile test on the adhesive riveting joint to obtain a double-hump tensile curve of the joint, wherein the horizontal axis of the double-hump tensile curve represents the tensile displacement and the vertical axis represents the load on the joint under tension, the test further includes:

[0029] The product of the adhesive failure load and the first strength ratio is set as the upper limit of the adhesive ratio; the first strength ratio is a real number greater than 1 and less than 2.

[0030] The product of the adhesive failure load and the second strength ratio is set as the lower limit of the adhesive ratio; the second strength ratio is a real number greater than 0 and less than 1.

[0031] If the riveting failure load is less than the lower limit of the adhesive bonding ratio, then the tested adhesive-riveted joint is determined to be mainly supported by adhesive bonding.

[0032] If the riveting failure load is not less than the lower limit of the adhesive bonding ratio and not greater than the upper limit of the adhesive bonding ratio, then the tested adhesive-riveted joint is determined to be supported by both adhesive bonding and riveting.

[0033] If the riveting failure load is greater than the upper limit of the adhesive bonding ratio, then the tested adhesive-riveted joint is determined to be mainly supported by riveting.

[0034] Preferably, after performing a tensile test on the adhesive riveting joint to obtain a double-hump tensile curve of the joint, wherein the horizontal axis of the double-hump tensile curve represents the tensile displacement and the vertical axis represents the load on the joint under tension, the test further includes:

[0035] The complete failure displacement of the adhesive joint under test is determined based on the double-hump tensile curve. The complete failure displacement is the abscissa corresponding to the minimum value between the first hump coordinate value and the second hump coordinate value of the double-hump tensile curve.

[0036] Calculate the first difference between the adhesive failure displacement and the adhesive failure tensile displacement;

[0037] If the first difference is 0, then the transition stability between the adhesive failure and the rivet load of the tested adhesive riveting joint is determined to be an over-stable transition from adhesive failure to rivet load.

[0038] If the first difference is greater than 0 and not greater than the preset maximum first difference, then the transition stability between the adhesive failure and the rivet bearing of the tested adhesive riveting joint is determined to be a stable transition from adhesive failure to rivet bearing.

[0039] If the first difference is greater than the preset maximum first difference, then the transition stability between the adhesive failure and the rivet bearing of the tested adhesive riveting joint is determined to be unstable.

[0040] Among them, the performance of transitioning from adhesive failure to rivet load-bearing stability is better than that of transitioning from adhesive failure to rivet load-bearing stability, and the performance of transitioning from adhesive failure to rivet load-bearing stability is better than that of transitioning from adhesive failure to rivet load-bearing instability.

[0041] Preferably, the riveting performance of the tested adhesive riveting joint is predicted based on the second hump coordinate value of the double-hump tensile curve, wherein the abscissa of the second hump coordinate value is the riveting failure tensile displacement when the tested adhesive riveting joint begins to fail, and the ordinate is the riveting failure load of the tested adhesive riveting joint, and the method further includes:

[0042] The complete failure load of the adhesive joint under test is determined based on the double-hump tensile curve, and the complete failure load is the ordinate corresponding to the complete failure displacement.

[0043] The peak slope of the riveting failure of the tested adhesive-bonded joint is determined based on the difference between the tensile displacement of the riveting failure and the displacement of the complete adhesive failure, as well as the difference between the riveting failure load and the load of the complete adhesive failure.

[0044] The riveting stiffness of the tested adhesive riveting joint is determined based on the slope of the riveting failure peak value, and the riveting stiffness is positively correlated with the slope of the riveting failure peak value.

[0045] Preferably, after performing a tensile test on the adhesive riveting joint to obtain a double-hump tensile curve of the joint, wherein the horizontal axis of the double-hump tensile curve represents the tensile displacement and the vertical axis represents the load on the joint under tension, the test further includes:

[0046] The complete failure displacement of the riveting joint under test is determined based on the double-hump tensile curve. The complete failure displacement is the abscissa corresponding to the minimum value after the second hump coordinate value of the double-hump tensile curve in the positive direction.

[0047] Calculate the second difference between the riveting failure displacement and the riveting failure tensile displacement;

[0048] If the second difference is not greater than the preset maximum second difference, then it is determined that the riveting failure performance of the tested adhesive riveting joint meets the preset riveting failure performance requirements.

[0049] If the second difference is greater than the preset maximum second difference, it is determined that the riveting failure performance of the tested adhesive riveting joint does not meet the preset riveting failure performance requirements, and that the compressive strength of the connected material is insufficient.

[0050] Preferably, the riveting performance of the tested adhesive riveting joint is predicted based on the second hump coordinate value of the double-hump tensile curve, wherein the abscissa of the second hump coordinate value is the riveting failure tensile displacement when the tested adhesive riveting joint begins to fail, and the ordinate is the riveting failure load when the tested adhesive riveting joint begins to fail; after the riveting performance of the tested adhesive riveting joint is positively correlated with the riveting failure tensile displacement and the riveting failure load, the method further includes:

[0051] The material failure load ratio is determined based on the connected material corresponding to the adhesive riveting joint under test; the material failure load ratio is a real number greater than 0 and less than 1.

[0052] The product obtained by multiplying the riveting failure load by the material failure load ratio is set as the first product;

[0053] To the right of the second hump coordinate value of the double-hump stretch curve, the horizontal coordinate corresponding to the product with the first hump as the vertical coordinate is set as the material failure displacement threshold value.

[0054] If the third difference between the material failure displacement threshold value and the tensile displacement of the riveting failure is not greater than the preset displacement threshold value, then it is determined that the performance of the connected material corresponding to the tested adhesive riveting joint meets the preset requirements.

[0055] If the third difference between the material failure displacement threshold value and the tensile displacement of the riveting failure is greater than the preset displacement threshold value, then it is determined that the performance of the connected material corresponding to the tested adhesive riveting joint does not meet the preset requirements, and the compressive strength of the connected material is insufficient.

[0056] To address the aforementioned technical problems, the present invention also provides a device for predicting the performance of adhesive riveting joints, comprising:

[0057] Memory, used to store computer programs;

[0058] A processor is used to implement the steps of the above-described method for predicting the performance of adhesive riveting joints when executing a computer program.

[0059] This application provides a method and apparatus for predicting the performance of adhesive-fitted riveting joints. After performing a tensile test on the joint, a double-hump tensile curve is obtained. Based on the abscissa and ordinate of the first hump of the double-hump tensile curve—that is, the tensile displacement and load at which the adhesive joint begins to fail—the adhesive performance of the joint is predicted. Similarly, based on the abscissa and ordinate of the second hump of the double-hump tensile curve—that is, the tensile displacement and load at which the riveting begins to fail—the riveting performance of the joint is predicted. Specifically, the double-hump tensile curve can be used to analyze the adhesive failure and riveting failure of the joint separately, thereby determining the adhesive and riveting performance respectively. This allows for targeted adjustments to the adhesive and riveting methods to improve the connection stability of the joint. Attached Figure Description

[0060] To more clearly illustrate 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.

[0061] Figure 1 A flowchart illustrating a method for predicting the performance of a glued joint provided by the present invention;

[0062] Figure 2 This invention provides a schematic diagram of a glued joint for connecting materials.

[0063] Figure 3 A schematic diagram of a double-hump stretch curve provided by the present invention;

[0064] Figure 4 This invention provides a schematic diagram of the limits for adhesive bonding failure and riveting failure.

[0065] Figure 5 A schematic diagram for predicting adhesive bonding performance provided by the present invention;

[0066] Figure 6 A schematic diagram for predicting riveting performance provided by the present invention;

[0067] Figure 7 A schematic diagram of the double-hump tensile curve for an example of predicting the performance of a glued joint under test provided by the present invention.

[0068] Figure 8 This is a schematic diagram of the structure of a performance prediction system for adhesive riveting joints provided by the present invention;

[0069] Figure 9This is a schematic diagram of the structure of a performance prediction device for adhesive riveting joints provided by the present invention. Detailed Implementation

[0070] The core of this invention is to provide a method and apparatus for predicting the performance of adhesive riveting joints. Specifically, it can analyze the adhesive failure and riveting failure of the tested adhesive riveting joints separately using a double-hump tensile curve, thereby determining the performance of the adhesive bonding and riveting respectively. This allows for targeted adjustments to the adhesive bonding method and the riveting method to improve the connection stability of the tested adhesive riveting joints.

[0071] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0072] Please refer to Figure 1 , Figure 1 This invention provides a flowchart illustrating a method for predicting the performance of adhesive-fitted joints. The method includes:

[0073] S11: Perform a tensile test on the rivet joint to obtain the double-hump tensile curve of the rivet joint. The horizontal axis of the double-hump tensile curve is the tensile displacement, and the vertical axis is the load on the rivet joint under tension.

[0074] Adhesive bonding is a process that uses the mechanical bonding force, physical adsorption force, and chemical bonding force generated by adhesives on the joint surfaces to join two bonded parts. Adhesive bonding is suitable not only for joining similar materials but also for joining dissimilar materials. The adhesive bonding process is simple, requires no complex equipment, and does not need to be performed under high temperature and pressure, thus the bonded parts are less prone to deformation, and the stress distribution at the joint is uniform. Under normal circumstances, adhesive joints have good sealing, electrical insulation, and corrosion resistance. Riveting, or rivet connection, is a mechanical term that uses axial force to thicken the rivet shank in the rivet hole of a part and form a rivet head, connecting multiple parts together. Adhesive riveting is a composite connection technology combining adhesive bonding and riveting. Adhesive riveting joints are adhesive joints that use both adhesive bonding and riveting. Adhesive riveting joints primarily rely on adhesive bonding, using rivets to improve the uneven pull strength and peel strength of the joint. In terms of process, rivets can be installed before the adhesive cures and then cured, or rivets can be installed after the adhesive cures. Adhesive riveting joints are simple and feasible, have good mechanical properties, and are also suitable for joining large-area components. Please refer to [reference needed]. Figure 2 , Figure 2This is a schematic diagram of a glued joint for connecting materials according to the present invention. The glued material 1 and material 2 are bonded together by an adhesive layer less than 1 mm thick, and the materials 1 and 2 are riveted together by the rivet.

[0075] Since adhesive riveting joints are commonly used in machinery manufacturing or aircraft manufacturing, and have high performance requirements, it is necessary to predict their performance. In existing technologies, the performance prediction of adhesive riveting joints typically involves tensile testing. This involves mounting the joint to be tested on the fixture of a tensile testing machine, ensuring that the joint can withstand stable stress during the tensile process. The installation of the joint should ensure that its axis is aligned with the force application centerline to avoid eccentric stress. By applying force to the joint, the failure time is observed, thus determining the overall performance of the joint based on its overall failure state. However, since the joint to be tested is a composite connection using both adhesive bonding and riveting, if the performance does not meet the requirements after determining the overall performance, adjustments must be made to either the riveting or adhesive bonding method, and the performance of the joint must be reassessed. Since there are many types of adhesive bonding and riveting methods, if the adhesive bonding performance and riveting performance of the joint to be tested cannot be determined separately, it is impossible to accurately adjust the joint to be tested.

[0076] To address the aforementioned technical issues, this application also performs tensile tests on the tested adhesive riveting joint when predicting its performance. However, during the tensile test, this application records the load and displacement of the tested adhesive riveting joint from the start of tension to complete failure. The load-displacement curve of the tested adhesive riveting joint in the tensile test, i.e., the double-hump tensile curve, is determined by the load and displacement throughout the process. The horizontal axis of the double-hump tensile curve represents the tensile displacement, and the vertical axis represents the load of the tested adhesive riveting joint.

[0077] In this test, since the tested adhesive-riveted joint is a composite connection of adhesive bonding and riveting, during the tensile process, the adhesive first bears the force, starting from a displacement of 0. The ordinate of the double-hump tensile curve initially increases with the abscissa, meaning the adhesive load of the tested joint increases with the displacement. When the adhesive load reaches its first maximum value, i.e., the first peak of the double-hump tensile curve, the tested adhesive-riveted joint begins to fail. Subsequently, the adhesive load decreases with the increase of displacement until the first minimum value, at which point the adhesive bonding of the tested joint completely fails. At this point, the riveting begins to bear the force, and the ordinate of the double-hump tensile curve again increases with the increase of displacement, meaning the riveting load increases with the increase of displacement. When the riveting load reaches its maximum value, i.e., the second peak of the double-hump tensile curve, the riveting begins to fail. Subsequently, the riveting load decreases with the increase of displacement until the riveting load no longer changes, at which point the riveting completely fails.

[0078] Please refer to Figure 3 , Figure 3 This is a schematic diagram of a double-hump tensile curve provided by the present invention. The horizontal axis represents displacement, denoted by the letter X, in mm; the vertical axis represents load, denoted by the letter F, in kN; point o is the starting point of the tensile test, with the coordinates of the origin, at which point only the adhesive bears the load; point a is the first hump, i.e., the beginning of adhesive failure, with the horizontal axis representing the tensile displacement at adhesive failure and the vertical axis representing the point corresponding to the adhesive failure load; oa represents the adhesive bearing stage, i.e., the adhesive bearing stage; point b is the point where the adhesive completely fails, from which the riveting bearing load begins; ob represents the adhesive failure process. ; ab represents interlaminar cracking failure, which means failure occurs within the joined materials, with the fiber matrix breaking and delaminating. The interface failure behavior of the adhesive riveting joint varies depending on the riveting material; point c is the second hump, which is the beginning of riveting failure. The horizontal axis represents the tensile displacement at riveting failure, and the vertical axis represents the point corresponding to the riveting failure load; bc represents the stage when the rivet begins to bear the load; point d represents complete riveting failure, which is the point where the entire adhesive riveting joint under test completely fails, and the rivet head detaches from the joined materials; cd represents the stage when the rivet head begins to be pulled off; bd represents the riveting failure process.

[0079] S12: The bonding performance of the tested adhesive riveting joint is predicted based on the first hump coordinate value of the double hump tensile curve. The horizontal axis of the first hump coordinate value is the bonding failure tensile displacement when the tested adhesive riveting joint begins to fail, and the vertical axis is the bonding failure load when the tested adhesive riveting joint begins to fail. The bonding performance of the tested adhesive riveting joint is positively correlated with the bonding failure tensile displacement and the bonding failure load.

[0080] Since the first peak of the double-hump tensile curve represents the coordinate values ​​corresponding to the tensile displacement and load at which the adhesive joint begins to fail, the adhesive performance can be predicted based on the horizontal and vertical coordinates of the first peak. Specifically, the larger the tensile displacement and load at the adhesive failure, the better the adhesive performance of the adhesive joint. Therefore, the adhesive performance of the adhesive joint can be determined based on the coordinate values ​​of the first peak of the double-hump tensile curve.

[0081] After determining the bonding performance, if the user is not satisfied with the bonding performance of the rivet joint under test, the bonding method of the rivet joint under test can be adjusted. There are various bonding methods, such as threaded connection, flange connection and clamp connection.

[0082] S13: The riveting performance of the tested adhesive riveting joint is predicted based on the second hump coordinate value of the double hump tensile curve. The horizontal axis of the second hump coordinate value is the riveting failure tensile displacement when the tested adhesive riveting joint begins to fail, and the vertical axis is the riveting failure load when the tested adhesive riveting joint begins to fail. The riveting performance of the tested adhesive riveting joint is positively correlated with the riveting failure tensile displacement and the riveting failure load.

[0083] Since the second peak of the double-hump tensile curve represents the coordinate values ​​corresponding to the riveting failure tensile displacement and riveting failure load when the riveting of the tested adhesive riveting joint begins to fail, the riveting performance can be predicted based on the horizontal and vertical coordinates of the second peak. Specifically, the larger the riveting failure tensile displacement and riveting failure load, the better the riveting performance of the tested adhesive riveting joint. Based on this, the riveting performance of the tested adhesive riveting joint can be determined based on the coordinate values ​​of the second peak of the double-hump tensile curve.

[0084] After determining the riveting performance, if the user is not satisfied with the riveting performance of the tested adhesive riveting joint, the riveting method of the tested adhesive riveting joint can be adjusted. There are many types of riveting methods, including hot press riveting, hot air riveting, ultrasonic riveting, plastic hot melt riveting, and pulse hot melt riveting.

[0085] It should be noted that this application does not limit the upper limit of the failure load of adhesive bonding and the upper limit of the failure load of riveting. The greater the load that the tested adhesive-riveted joint can bear, the better its performance.

[0086] The adhesive bonding and riveting performance described in this application are all preset, and the processor determines the performance of the adhesive-riveting joint under test based on the values ​​of the double-hump tensile curve. After the processor determines the performance of the adhesive-riveting joint under test, the user can make targeted improvements to the adhesive-riveting joint under test based on the determined performance, thereby improving the improvement efficiency of the adhesive-riveting joint under test.

[0087] In summary, this embodiment can specifically analyze the failure of the adhesive bonding and the failure of the riveting joint under test using the double-hump tensile curve, thereby determining the performance of the adhesive bonding and the riveting joint respectively, so as to make targeted adjustments to the adhesive bonding method and the riveting method respectively, and improve the connection stability of the adhesive riveting joint under test.

[0088] Based on the above embodiments:

[0089] As a preferred embodiment, the bonding performance of the tested adhesive riveting joint is predicted based on the coordinate value of the first hump of the double-hump tensile curve. The abscissa of the first hump coordinate value is the tensile displacement at which the adhesive riveting joint begins to fail, and the ordinate is the tensile load at which the adhesive riveting joint begins to fail. The bonding performance of the tested adhesive riveting joint is positively correlated with the tensile displacement at the tensile failure and the tensile load at the tensile failure, including:

[0090] Based on the x-coordinate and y-coordinate of the first hump coordinate value of the double-hump tensile curve, the tensile displacement and load at which the glued joint under test begins to fail are determined respectively.

[0091] If the tensile displacement of the adhesive failure is not less than the preset minimum adhesive failure displacement, and the adhesive failure load is not less than the minimum adhesive failure load, then the adhesive performance of the tested adhesive riveting joint is determined to meet the preset adhesive performance requirements.

[0092] If the tensile displacement due to adhesive failure is less than the preset minimum adhesive failure displacement, and / or the adhesive failure load is less than the minimum adhesive failure load, then the adhesive performance of the tested adhesive riveting joint is determined to be unsatisfactory.

[0093] When determining the bonding performance of the rivet joint under test, specifically, the bonding performance of the rivet joint under test meets the preset bonding performance only when the bonding failure tensile displacement is not less than the preset minimum bonding failure displacement and the bonding failure load is not less than the minimum bonding failure load. Based on this, the coordinate value of the first hump of the double-hump tensile curve can be used to determine whether the bonding performance meets the preset bonding performance requirements, thereby determining whether the bonding method of the rivet joint under test needs to be adjusted to improve the overall performance of the rivet joint under test.

[0094] Please refer to Figure 4 , Figure 4 This invention provides a schematic diagram of the limits for adhesive bonding failure and riveting failure.

[0095] Among them, the minimum adhesive failure displacement and the minimum adhesive failure load can be, but are not limited to, being set based on the type of materials being joined or the application scenario requirements of the adhesive riveting joint under test.

[0096] As a preferred embodiment, if the tensile displacement due to adhesive failure is less than the preset minimum adhesive failure displacement, and / or the adhesive failure load is less than the minimum adhesive failure load, then the adhesive performance of the tested adhesive-fitted joint is determined to not meet the preset adhesive performance requirements, including:

[0097] If the tensile displacement of the adhesive failure is less than the minimum adhesive failure displacement, but the adhesive failure load is not less than the minimum adhesive failure load, then the adhesive performance of the tested adhesive joint is determined to be insufficient.

[0098] If the tensile displacement of the adhesive failure is not less than the minimum adhesive failure displacement, but the adhesive failure load is less than the minimum adhesive failure load, then the adhesive performance of the tested adhesive riveting joint is determined to be insufficient adhesive layer bonding strength.

[0099] If the tensile displacement at the adhesive failure point is less than the minimum adhesive failure point, and the adhesive failure load is less than the minimum adhesive failure load, then the adhesive performance of the tested adhesive riveting joint is determined to be insufficient adhesive performance and insufficient adhesive layer bonding strength.

[0100] In this embodiment, the specific situations when the bonding performance of the tested adhesive riveting joint does not meet the preset bonding performance requirements are classified, that is, the specific reasons for the bonding performance of the tested adhesive riveting joint not meeting the preset bonding performance requirements are determined.

[0101] Specifically, if the tensile displacement of the adhesive failure is less than the minimum adhesive failure displacement, but the adhesive failure load is not less than the minimum adhesive failure load, then the adhesive of the rivet joint under test begins to fail when the tensile displacement is small. Since the load of the rivet joint under test is still not less than the minimum adhesive failure load, it can be determined that the adhesive performance of the rivet joint under test is insufficient, that is, the adhesive viscosity is insufficient, which causes the adhesive method of the rivet joint under test to be unable to withstand a large tensile displacement, or the displacement is too short and the adhesive performance is insufficient.

[0102] If the tensile displacement due to adhesive failure is not less than the minimum adhesive failure displacement, and only the adhesive failure load is less than the minimum adhesive failure load, then the load on the adhesive riveting joint under test is relatively small when stretched. Since the displacement of the adhesive riveting joint under test is still not less than the minimum adhesive failure displacement, it can be determined that the adhesive performance of the adhesive riveting joint under test is that the adhesive layer bonding strength is insufficient, that is, the adhesive layer bonding strength is low and easy to crack. At this time, the adhesive bonding strength of the adhesive layer bonding surface of the adhesive riveting joint under test is insufficient and it is easy to be stretched to crack.

[0103] If not only is the tensile displacement at the adhesive failure point less than the minimum adhesive failure displacement, but the adhesive failure load is also less than the minimum adhesive failure load, then when the tested adhesive riveting joint is stretched, not only is its tensile displacement small, but its load is also small. Since the displacement of the tested adhesive riveting joint is still not less than the minimum adhesive failure displacement, it can be determined that the adhesive performance of the tested adhesive riveting joint at this time is due to insufficient adhesive performance and insufficient bonding strength of the adhesive layer. In other words, the adhesive performance and bonding surface performance cause the adhesive performance to fail to meet the requirements.

[0104] Based on this, after determining why the bonding performance of the tested adhesive riveting joint does not meet the preset bonding performance requirements, the bonding method can be adjusted in a targeted manner to improve the bonding performance of the tested adhesive riveting joint.

[0105] Please refer to Table 1:

[0106] Table 1 Correspondence Table for Adhesive Bonding Performance Prediction

[0107]

[0108] in, For adhesive failure load, This refers to the tensile displacement due to adhesive failure. The minimum adhesive failure load, This represents the minimum adhesive failure displacement.

[0109] Please refer to Figure 5 , Figure 5 This is a schematic diagram illustrating the prediction of adhesive bonding performance provided by the present invention.

[0110] In a preferred embodiment, a tensile test is performed on the adhesive riveting joint to obtain a double-hump tensile curve of the joint. The horizontal axis of the double-hump tensile curve represents the tensile displacement, and the vertical axis represents the load on the adhesive riveting joint under tension. The test also includes:

[0111] The peak slope of the adhesive failure of the tested adhesive riveting joint was determined based on the tensile displacement and load of adhesive failure.

[0112] The bonding stiffness of the tested adhesive riveting joint is determined based on the slope of the peak bonding failure. The bonding stiffness is positively correlated with the slope of the peak bonding failure.

[0113] In this embodiment, the slope of the double-hump stretching curve before the first hump can also be used as a basis, i.e. Figure 5 k1 is used to determine the peak slope of the adhesive failure of the joint under test. The larger the peak slope of the adhesive failure, the greater the adhesive stiffness and the stronger the adhesive material's ability to resist elastic deformation under stress.

[0114] As a preferred embodiment, the riveting performance of the tested adhesive riveting joint is predicted based on the coordinate value of the second hump of the double-hump tensile curve. The abscissa of the second hump coordinate value is the riveting failure tensile displacement when the tested adhesive riveting joint begins to fail, and the ordinate is the riveting failure load when the tested adhesive riveting joint begins to fail. The riveting performance of the tested adhesive riveting joint is positively correlated with the riveting failure tensile displacement and the riveting failure load, including:

[0115] The horizontal and vertical coordinates of the second hump coordinates of the double-hump tensile curve are used to determine the tensile displacement and load at which the rivet joint begins to fail.

[0116] If the tensile displacement due to riveting failure is not less than the preset minimum riveting failure displacement, and the load due to riveting failure is not less than the minimum load due to riveting failure, then the riveting performance of the tested adhesive riveting joint is determined to meet the preset riveting performance requirements.

[0117] If the tensile displacement due to riveting failure is less than the preset minimum riveting failure displacement, and / or the load due to riveting failure is less than the minimum load due to riveting failure, then the riveting performance of the tested adhesive riveting joint is determined to be unsatisfactory according to the preset riveting performance requirements.

[0118] When determining the riveting performance of the adhesive riveting joint under test, specifically, the riveting performance of the adhesive riveting joint under test meets the preset riveting performance only when the tensile displacement at riveting failure is not less than the preset minimum riveting failure displacement and the load at riveting failure is not less than the minimum load at riveting failure. Based on this, the coordinate value of the second hump of the double-hump tensile curve can be used to determine whether the riveting performance meets the preset riveting performance requirements, thereby determining whether the riveting method of the adhesive riveting joint under test needs to be adjusted to improve the overall performance of the adhesive riveting joint under test.

[0119] Among them, the minimum riveting failure displacement and the minimum riveting failure load can be, but are not limited to, being set based on the type of connected materials or the application scenario requirements of the adhesive riveting joint under test.

[0120] As a preferred embodiment, if the tensile displacement due to riveting failure is less than the preset minimum riveting failure displacement, and / or the load due to riveting failure is less than the minimum load due to riveting failure, then the riveting performance of the tested adhesive riveting joint is determined to not meet the preset riveting performance requirements, including:

[0121] If the tensile displacement of the riveting failure is less than the minimum riveting failure displacement, but the riveting failure load is not less than the minimum riveting failure load, then the riveting performance of the tested adhesive riveting joint is determined to be insufficient for either the rivet or the material being connected.

[0122] If the tensile displacement of the riveting failure is not less than the minimum riveting failure displacement, but the riveting failure load is less than the minimum riveting failure load, then the riveting performance of the tested adhesive riveting joint is determined to be insufficient rivet clamping.

[0123] If the tensile displacement of the riveting failure is less than the minimum riveting failure displacement, and the riveting failure load is less than the minimum riveting failure load, then the riveting performance of the tested adhesive riveting joint is determined to be insufficient due to inadequate performance of the rivet or the connected material and insufficient rivet clamping.

[0124] In this embodiment, the specific situations when the riveting performance of the tested adhesive riveting joint does not meet the preset riveting performance requirements are classified, that is, the specific reasons for the failure of the tested adhesive riveting joint to meet the preset riveting performance requirements are determined.

[0125] Specifically, if the tensile displacement of the riveting failure is less than the minimum riveting failure displacement, but the riveting failure load is not less than the minimum riveting failure load, then the riveting of the tested adhesive riveting joint begins to fail when the tensile displacement is small. Since the load of the tested adhesive riveting joint is still not less than the minimum riveting failure load, it can be determined that the riveting performance of the tested adhesive riveting joint at this time is due to insufficient performance of the rivet or the connected material, that is, the displacement is too short and the performance of the rivet or the connected material is insufficient, resulting in the riveting method of the tested adhesive riveting joint being unable to withstand a large tensile displacement.

[0126] If the tensile displacement due to riveting failure is not less than the minimum riveting failure displacement, and only the load due to riveting failure is less than the minimum riveting failure load, then the load on the tested adhesive riveting joint is relatively small when stretched. Since the displacement of the tested adhesive riveting joint is still not less than the minimum riveting failure displacement, it can be determined that the riveting performance of the tested adhesive riveting joint at this time is insufficient rivet clamping, and the riveting strength of the tested adhesive riveting joint is insufficient.

[0127] If not only is the tensile displacement of the riveting failure less than the minimum riveting failure displacement, but the load of the riveting failure is also less than the minimum riveting failure load, then when the tested adhesive riveting joint is stretched, not only is the tensile displacement it can withstand small, but its load is also small. Since the displacement of the tested adhesive riveting joint is still not less than the minimum riveting failure displacement, it can be determined that the riveting performance of the tested adhesive riveting joint at this time is that the rivet or the material being connected is inadequate and the rivet is not tightened enough.

[0128] Based on this, after determining why the riveting performance of the tested adhesive riveting joint does not meet the preset riveting performance requirements, the riveting method can be adjusted in a targeted manner to improve the riveting performance of the tested adhesive riveting joint.

[0129] Please refer to Table 2:

[0130] Table 2 Correspondence Table for Riveting Performance Prediction

[0131]

[0132] in, For riveting failure load, The tensile displacement is due to riveting failure. The minimum riveting failure load, This represents the minimum displacement at which the riveting fails.

[0133] Please refer to Figure 6 , Figure 6 This is a schematic diagram for predicting riveting performance provided by the present invention.

[0134] In a preferred embodiment, a tensile test is performed on the adhesive riveting joint to obtain a double-hump tensile curve of the joint. The horizontal axis of the double-hump tensile curve represents the tensile displacement, and the vertical axis represents the load on the joint under tension. The test also includes:

[0135] The contribution of adhesive failure load and riveting failure load to the adhesive performance and riveting performance of the tested joint is predicted.

[0136] In this embodiment, not only are the adhesive bonding performance and riveting performance of the tested adhesive riveting joint predicted, but the contribution of adhesive bonding performance and riveting performance of the tested adhesive riveting joint are also predicted. That is, it is determined whether the load in the tested adhesive riveting joint is mainly borne by adhesive bonding or by riveting, so as to make targeted adjustments to adhesive bonding and riveting.

[0137] As a preferred embodiment, the contribution of the adhesive failure load and the riveting failure load to the adhesive-riveted joint under test is predicted, including:

[0138] The product of the adhesive failure load and the first strength ratio is set as the upper limit of the adhesive ratio; the first strength ratio is a real number greater than 1 and less than 2;

[0139] The product of the adhesive failure load and the second strength ratio is set as the lower limit of the adhesive ratio; the second strength ratio is a real number greater than 0 and less than 1.

[0140] If the failure load of riveting is less than the lower limit of adhesive bonding ratio, then the adhesive bonding load is determined to be the main load-bearing component of the tested adhesive-riveted joint.

[0141] If the failure load of riveting is not less than the lower limit of adhesive bonding ratio and not greater than the upper limit of adhesive bonding ratio, then the tested adhesive-riveted joint is determined to be jointly borne by adhesive bonding and riveting.

[0142] If the failure load of riveting is greater than the upper limit of adhesive bonding ratio, then the tested adhesive-riveted joint is determined to be mainly supported by riveting.

[0143] In this embodiment, the adhesive strength is used as the boundary, and the upper limit and lower limit of the adhesive ratio are set based on the adhesive failure load. If the riveting failure load is between the lower limit and the upper limit of the adhesive ratio, the adhesive and riveting strength ratios of the tested adhesive-riveting joint are matched, indicating that the tested adhesive-riveting joint is supported by both adhesive and riveting, and is mainly used in the connection of medium-strength structural components.

[0144] If the failure load of riveting is less than the lower limit of adhesive bonding ratio, then the low strength ratio of adhesive riveting is matched, and the joint is mainly used in the connection of low strength thin-walled parts with adhesive bearing position and rivet bearing as auxiliary.

[0145] If the failure load of riveting is greater than the upper limit of adhesive bonding ratio, then the high strength matching of adhesive riveting is used. The tested adhesive riveting joint is mainly supported by riveting and supplemented by adhesive bonding. Adhesive bonding mainly plays the role of sealing and potential isolation, and is mainly used in the connection of high strength structural components.

[0146] Specifically, the first strength ratio can be 120%, and the upper limit of the adhesive bonding ratio is 120% of the adhesive bonding failure load; the second strength ratio can be 90%, that is, the lower limit of the adhesive bonding ratio is 90% of the adhesive bonding failure load; the first strength ratio and the second strength ratio can be determined according to the actual application scenario of the adhesive riveting joint to be tested.

[0147] Please refer to Figure 3 :

[0148] Table 3. Correspondence Table for Predicted Contribution of Adhesive Riveting

[0149]

[0150] In a preferred embodiment, a tensile test is performed on the adhesive riveting joint to obtain a double-hump tensile curve of the joint. The horizontal axis of the double-hump tensile curve represents the tensile displacement, and the vertical axis represents the load on the joint under tension. The test also includes:

[0151] The complete failure displacement of the adhesive joint under test is determined based on the double-hump tensile curve. The complete failure displacement is the abscissa corresponding to the minimum value between the first hump coordinate value and the second hump coordinate value of the double-hump tensile curve.

[0152] The transition stability of the adhesive joint under test from adhesive failure to rivet bearing capacity is determined by the difference between the tensile displacement due to adhesive failure and the displacement due to complete adhesive failure.

[0153] In this embodiment, the uniqueness of the adhesive failure process of the tested adhesive riveting joint can also be determined to determine the stability of the tested adhesive riveting joint when it transitions from adhesive bonding to riveting, that is, the stability of the tested adhesive riveting joint from the beginning of adhesive failure to complete failure, that is, the period from the start of adhesive failure to the start of riveting bearing load.

[0154] As a preferred embodiment, the transition stability from adhesive failure to rivet load of the tested adhesive-bonded riveted joint is determined based on the difference between the tensile displacement at adhesive failure and the displacement at complete adhesive failure, including:

[0155] The first difference is obtained by subtracting the tensile displacement at the complete failure of the adhesive bond from the tensile displacement at the failure of the adhesive bond.

[0156] If the first difference is 0, then the transition stability between the adhesive failure and the rivet load of the tested adhesive riveting joint is determined to be the overstability transition from adhesive failure to rivet load.

[0157] If the first difference is greater than 0 and not greater than the preset maximum first difference, then the transition stability between the adhesive failure and the rivet load of the tested adhesive riveting joint is determined to be the stable transition from adhesive failure to rivet load.

[0158] If the first difference is greater than the preset maximum first difference, then the transition stability between the adhesive failure and the rivet load of the tested adhesive riveting joint is determined to be unstable.

[0159] Among them, the performance of transitioning from adhesive failure to rivet load-bearing stability is better than that of transitioning from adhesive failure to rivet load-bearing stability, and the performance of transitioning from adhesive failure to rivet load-bearing stability is better than that of transitioning from adhesive failure to rivet load-bearing instability.

[0160] In this embodiment, if the first difference is 0, that is, the moment the adhesive begins to fail, the riveting begins to bear the load. At this time, the transition from adhesive failure to rivet bearing is very stable. If the first difference is greater than 0 and not greater than the preset maximum first difference, after the adhesive begins to fail, there will be a displacement. However, when the displacement does not exceed the preset maximum first difference, the riveting begins to bear the load. Although the transition from adhesive failure to rivet bearing is stable, its stability is still not as good as the transition stability between adhesive failure and rivet bearing when the first difference is 0. If the first difference is greater than the preset maximum first difference, after the adhesive begins to fail, there will be a long time before the riveting begins to bear the load. At this time, there is a large fluctuation in the transition from adhesive failure to rivet bearing, and the joint stability is poor. For example, if the connected material has been stretched and deformed after the adhesive begins to fail before the riveting begins to bear the load, the stability is poor.

[0161] Please refer to Table 4:

[0162] Table 4. Correspondence Table for Judging Stability of Adhesive Bonding Failure

[0163]

[0164] in, The first difference, This is the preset maximum first difference value.

[0165] As a preferred embodiment, the riveting performance of the tested adhesive riveting joint is predicted based on the second hump coordinate value of the double-hump tensile curve. The abscissa of the second hump coordinate value is the riveting failure tensile displacement when the tested adhesive riveting joint begins to fail, and the ordinate is the riveting failure load of the tested adhesive riveting joint. The method further includes:

[0166] The complete failure load of the adhesive joint under test is determined based on the double-hump tensile curve. The complete failure load is the ordinate corresponding to the complete failure displacement.

[0167] The peak slope of the riveting failure of the tested adhesive-bonded joint is determined based on the difference between the tensile displacement of the riveting failure and the displacement of the complete adhesive failure, as well as the difference between the riveting failure load and the complete adhesive failure load.

[0168] The riveting stiffness of the tested adhesive riveting joint is determined based on the peak slope of the riveting failure. The riveting stiffness is positively correlated with the peak slope of the riveting failure.

[0169] In this embodiment, the slope of the double-hump tensile curve before the second hump can also be used to determine the peak slope of the riveting failure of the tested adhesive riveting joint. A larger peak slope indicates greater riveting stiffness and stronger resistance to elastic deformation of the riveting material under stress. Figure 6 k2 in the middle.

[0170] It should be noted that the peak slope of the riveting failure at this time is calculated from the load at which the adhesive bonding completely fails.

[0171] In a preferred embodiment, a tensile test is performed on the adhesive riveting joint to obtain a double-hump tensile curve of the joint. The horizontal axis of the double-hump tensile curve represents the tensile displacement, and the vertical axis represents the load on the adhesive riveting joint under tension. The test also includes:

[0172] The complete failure displacement of the riveting joint under test is determined based on the double-hump tensile curve. The complete failure displacement is the abscissa corresponding to the minimum value after the second hump coordinate value of the double-hump tensile curve in the positive direction.

[0173] The second difference is obtained by subtracting the tensile displacement at riveting failure from the displacement at complete riveting failure.

[0174] If the second difference is not greater than the preset maximum second difference, then the riveting failure performance of the tested adhesive riveting joint is determined to meet the preset riveting failure performance requirements.

[0175] If the second difference is greater than the preset maximum second difference, it is determined that the riveting failure performance of the tested adhesive riveting joint does not meet the preset riveting failure performance requirements, and that the compressive strength of the connected material is insufficient.

[0176] In this embodiment, if the second difference is not greater than the preset maximum second difference, it is determined that the riveting failure performance of the tested adhesive riveting joint meets the preset riveting failure performance requirements. The main failure modes are rivet cutting, pull-out, or tearing. The compressive strength of the connected material is within acceptable limits, meaning the riveting failure is caused by the rivet being pulled off or broken. If the second difference is greater than the preset maximum second difference, it is determined that the riveting failure performance of the tested adhesive riveting joint does not meet the preset riveting failure performance requirements. The main deformation is tearing, and the compressive strength of the connected material does not meet the requirements. In other words, when the rivet completely fails, the connected material has already undergone significant deformation, such as being pulled into a large hole. The rivet can no longer bear the load, and adjustments can be made to the connected material in this case.

[0177] As a preferred embodiment, the riveting performance of the tested adhesive riveting joint is predicted based on the coordinate value of the second hump of the double-hump tensile curve. The abscissa of the second hump coordinate value is the riveting failure tensile displacement when the tested adhesive riveting joint begins to fail, and the ordinate is the riveting failure load when the tested adhesive riveting joint begins to fail. After the riveting performance of the tested adhesive riveting joint is positively correlated with the riveting failure tensile displacement and the riveting failure load, the method further includes:

[0178] The material failure load ratio is determined based on the connected material corresponding to the adhesive riveting joint under test; the material failure load ratio is a real number greater than 0 and less than 1.

[0179] The product obtained by multiplying the riveting failure load by the material failure load ratio is set as the first product;

[0180] To the right of the second hump coordinate value of the double-hump stretch curve, the horizontal coordinate corresponding to the product with the first hump as the vertical coordinate is set as the material failure displacement threshold value.

[0181] If the third difference between the material failure displacement threshold value and the tensile displacement at riveting failure is not greater than the preset displacement threshold value, then the performance of the connected material corresponding to the tested adhesive riveting joint is determined to meet the preset requirements.

[0182] If the third difference between the material failure displacement threshold value and the tensile displacement at riveting failure is greater than the preset displacement threshold value, then it is determined that the performance of the connected material corresponding to the tested adhesive riveting joint does not meet the preset requirements, and that the compressive strength of the connected material is insufficient.

[0183] In this embodiment, it can be determined whether the connected materials are sufficient to meet the preset requirements, such as based on the displacement and load of the riveting during the failure process after the riveting begins to fail. Specifically, it can be based on a first product obtained by multiplying the riveting failure load by the material failure load ratio. The vertical axis of the double-hump tensile curve corresponding to this first product represents the load from the start of failure to complete failure of the tested adhesive riveting joint. This load is selected based on the connected materials of the tested adhesive riveting joint, and the tensile displacement of the tested adhesive riveting joint is determined when the load is the first product. Here, the tensile displacement is the tensile displacement during the riveting failure process. A third difference is obtained by subtracting the riveting failure tensile displacement from the material failure displacement threshold value. If the third difference is not greater than the preset displacement threshold value, it indicates that the tested adhesive riveting joint bears the load. When the load is the first product, the material failure displacement threshold is small, meaning the displacement after the riveting begins to fail is small. At this time, the resistance to compressive stress of the connected materials is good, and they are not easily deformed or damaged. If the third difference is greater than the preset displacement threshold, it means that when the load on the tested adhesive riveting joint is the first product, the material failure displacement threshold is large, meaning the displacement after the riveting begins to fail is large. At this time, the resistance to compressive stress of the connected materials is poor, and they are easily deformed and damaged. If the displacement of the rivet under tension is already large, the load it bears is not large, but the connected materials are pulled out with large holes, and the rivet is no longer the main load-bearing part.

[0184] Please refer to Figure 5 :

[0185] Figure 5 Failure prediction correspondence table of connected materials

[0186]

[0187] in, The third difference, To preset the maximum third difference, This represents the proportion of material failure load.

[0188] Please refer to Figure 7 , Figure 7 This is a schematic diagram of the double-hump tensile curve for an example of predicting the performance of a test adhesive riveting joint provided by the present invention. The figure shows the double-hump tensile curves of the test adhesive riveting joints after tensile testing of sample 1 (model 303-4-7) and sample 2 (model 303-4-8), and refers to Table 6.

[0189] Table 6. Correspondence Table of Test Examples for the Performance of Adhesive Rivet Joints Under Test

[0190]

[0191] It can be seen that the adhesive failure load of sample 1 is 9.87, which is greater than the minimum adhesive failure load of 8.0. The adhesive failure tensile displacement of sample 1 is 1.3 mm, which is greater than the minimum adhesive failure displacement of 1.0. Therefore, it can be determined that sample 1 meets the preset adhesive performance requirements. The first difference is 0.6, which is greater than 0 and less than the preset maximum first difference of 1. Therefore, the transition stability between adhesive failure and rivet load of sample 1 is determined to be a stable transition from adhesive failure to rivet load. The riveting failure load is 19.69, which is greater than the minimum riveting failure load of 16.5. The riveting failure tensile displacement of sample 1 is 4.4, which is greater than the minimum riveting failure displacement of 3.5. Therefore, it can be determined that sample 1 meets the preset riveting performance requirements. The material failure load ratio is set to 50%, and the load of sample 1 is... When the tensile displacement is 4.5, which is less than the preset maximum third difference of 8, it is determined that the performance of the connected material corresponding to sample 1 meets the preset requirements.

[0192] The adhesive failure load of sample 2 is 3.95, which is less than the minimum adhesive failure load of 8.0. The adhesive failure tensile displacement is 0.52, which is less than the minimum adhesive failure displacement of 1.0. Therefore, it can be determined that sample 2 does not meet the preset adhesive performance requirements. The adhesive performance of sample 2 is determined to be due to the adhesive performance and bonding surface performance. The first difference is 0.4, which is greater than 0 and less than the preset maximum first difference of 1. Therefore, the transition stability between adhesive failure and rivet load of sample 2 is determined to be a stable transition from adhesive failure to rivet load. The riveting failure load is 17.88, which is greater than the minimum riveting failure load of 16.5. The riveting failure tensile displacement of sample 1 is 4.6, which is greater than the minimum riveting failure displacement of 3.5. Therefore, it can be determined that sample 1 meets the preset riveting performance requirements. The material failure load ratio is set to 50%, and the load of sample 2 is... When the tensile displacement is 6.5, which is less than the preset maximum third difference of 8, it is determined that the performance of the connected material corresponding to sample 2 meets the preset requirements.

[0193] It should be noted that the above-mentioned peak coordinates of adhesive failure are the coordinates corresponding to the adhesive failure load and the adhesive failure tensile displacement, the adhesive failure limit coordinates are the coordinates corresponding to the minimum adhesive failure load and the minimum adhesive failure displacement, the peak coordinates of riveting failure are the coordinates corresponding to the riveting failure load and the riveting failure tensile displacement, and the riveting failure limit coordinates are the coordinates corresponding to the minimum riveting failure load and the minimum riveting failure displacement.

[0194] Please refer to Figure 8 , Figure 8 This is a schematic diagram of a performance prediction system for adhesive riveting joints provided by the present invention. The system includes:

[0195] The curve acquisition unit 81 is used to perform a tensile test on the adhesive riveting joint under test to obtain the double-hump tensile curve of the adhesive riveting joint under test. The horizontal axis of the double-hump tensile curve is the tensile displacement, and the vertical axis is the load of the adhesive riveting joint under test when it is stretched.

[0196] The adhesive bonding test unit 82 is used to predict the adhesive bonding performance of the joint under test based on the first hump coordinate value of the double-hump tensile curve. The horizontal axis of the first hump coordinate value is the adhesive bonding failure tensile displacement when the joint under test begins to fail, and the vertical axis is the adhesive bonding failure load when the joint under test begins to fail. The adhesive bonding performance of the joint under test is positively correlated with the adhesive bonding failure tensile displacement and the adhesive bonding failure load.

[0197] The riveting test unit 83 is used to predict the riveting performance of the tested adhesive riveting joint based on the second hump coordinate value of the double-hump tensile curve. The horizontal axis of the second hump coordinate value is the riveting failure tensile displacement when the tested adhesive riveting joint begins to fail, and the vertical axis is the riveting failure load when the tested adhesive riveting joint begins to fail. The riveting performance of the tested adhesive riveting joint is positively correlated with the riveting failure tensile displacement and the riveting failure load.

[0198] For a description of the performance prediction system for adhesive riveting joints provided by this invention, please refer to the above method embodiments; the invention itself will not be described in detail here.

[0199] Please refer to Figure 9 , Figure 9 This is a schematic diagram of a device for predicting the performance of a glued joint provided by the present invention. The device includes:

[0200] Memory 91 is used to store computer programs;

[0201] The processor 92 is used to implement the steps of the above-described method for predicting the performance of adhesive riveting joints when executing a computer program.

[0202] For a description of the performance prediction device for the adhesive riveting joint provided by the present invention, please refer to the above method embodiments; the present invention will not be described again here.

[0203] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0204] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for predicting the performance of a glued joint, characterized in that, include: A tensile test is performed on the rivet joint to obtain the double-hump tensile curve of the rivet joint. The horizontal axis of the double-hump tensile curve is the tensile displacement, and the vertical axis is the load of the rivet joint under tension. The bonding performance of the tested adhesive riveting joint is predicted based on the first hump coordinate value of the double-hump tensile curve. The horizontal axis of the first hump coordinate value is the bonding failure tensile displacement when the tested adhesive riveting joint begins to fail, and the vertical axis is the bonding failure load when the tested adhesive riveting joint begins to fail. The bonding performance of the tested adhesive riveting joint is positively correlated with the bonding failure tensile displacement and the bonding failure load. The riveting performance of the tested adhesive riveting joint is predicted based on the second hump coordinate value of the double-hump tensile curve. The horizontal axis of the second hump coordinate value is the riveting failure tensile displacement when the tested adhesive riveting joint begins to fail, and the vertical axis is the riveting failure load when the tested adhesive riveting joint begins to fail. The riveting performance of the tested adhesive riveting joint is positively correlated with the riveting failure tensile displacement and the riveting failure load. A tensile test is performed on the adhesive riveting joint under test to obtain a double-hump tensile curve of the joint. The horizontal axis of the double-hump tensile curve represents the tensile displacement, and the vertical axis represents the load on the joint under test during tension. The test also includes: The complete failure displacement of the adhesive joint under test is determined based on the double-hump tensile curve. The complete failure displacement is the abscissa corresponding to the minimum value between the first hump coordinate value and the second hump coordinate value of the double-hump tensile curve. Calculate the first difference between the adhesive failure displacement and the adhesive failure tensile displacement; If the first difference is 0, then the transition stability between the adhesive failure and the rivet load of the tested adhesive riveting joint is determined to be an over-stable transition from adhesive failure to rivet load. If the first difference is greater than 0 and not greater than the preset maximum first difference, then the transition stability between the adhesive failure and the rivet bearing of the tested adhesive riveting joint is determined to be a stable transition from adhesive failure to rivet bearing. If the first difference is greater than the preset maximum first difference, then the transition stability between the adhesive failure and the rivet bearing of the tested adhesive riveting joint is determined to be unstable. Among them, the performance of transitioning from adhesive failure to rivet load-bearing stability is better than that of transitioning from adhesive failure to rivet load-bearing stability, and the performance of transitioning from adhesive failure to rivet load-bearing stability is better than that of transitioning from adhesive failure to rivet load-bearing instability.

2. The method for predicting the performance of adhesive-fitted joints as described in claim 1, characterized in that, The bonding performance of the tested adhesive riveting joint is predicted based on the first hump coordinate value of the double hump tensile curve. The horizontal axis of the first hump coordinate value is the bonding failure tensile displacement when the tested adhesive riveting joint begins to fail, and the vertical axis is the bonding failure load when the tested adhesive riveting joint begins to fail. The bonding performance of the tested adhesive riveting joint is positively correlated with the tensile displacement at bonding failure and the load at bonding failure, including: Based on the abscissa and ordinate of the first hump coordinate value of the double-hump tensile curve, the tensile displacement of the adhesive joint failure and the adhesive joint failure load at the point when the tested adhesive joint begins to fail are determined respectively. If the tensile displacement of the adhesive failure is not less than the preset minimum adhesive failure displacement, and the adhesive failure load is not less than the minimum adhesive failure load, then the adhesive performance of the tested adhesive riveting joint is determined to meet the preset adhesive performance requirements. If the tensile displacement of the adhesive failure is less than the preset minimum adhesive failure displacement, and / or the adhesive failure load is less than the minimum adhesive failure load, then it is determined that the adhesive performance of the tested adhesive riveting joint does not meet the preset adhesive performance requirements.

3. The method for predicting the performance of adhesive-fitted joints as described in claim 2, characterized in that, If the adhesive failure tensile displacement is less than the preset minimum adhesive failure displacement, and / or the adhesive failure load is less than the minimum adhesive failure load, then the adhesive performance of the tested adhesive riveting joint is determined to not meet the preset adhesive performance requirements, including: If the tensile displacement of the adhesive failure is less than the minimum adhesive failure displacement, but the adhesive failure load is not less than the minimum adhesive failure load, then the adhesive performance of the tested adhesive joint is determined to be insufficient. If the tensile displacement of the adhesive failure is not less than the minimum adhesive failure displacement, but the adhesive failure load is less than the minimum adhesive failure load, then the adhesive performance of the tested adhesive joint is determined to be insufficient adhesive layer bonding strength. If the tensile displacement of the adhesive failure is less than the minimum adhesive failure displacement, and the adhesive failure load is less than the minimum adhesive failure load, then the adhesive performance of the tested adhesive riveting joint is determined to be insufficient adhesive performance and insufficient adhesive layer bonding strength.

4. The method for predicting the performance of adhesive-fitted joints as described in claim 1, characterized in that, A tensile test is performed on the adhesive riveting joint under test to obtain a double-hump tensile curve of the joint. The horizontal axis of the double-hump tensile curve represents the tensile displacement, and the vertical axis represents the load on the joint under test during tension. The test also includes: The peak slope of the adhesive failure of the tested adhesive riveting joint is determined based on the adhesive failure tensile displacement and the adhesive failure load. The adhesive stiffness of the tested adhesive riveting joint is determined based on the slope of the adhesive failure peak value, and the adhesive stiffness is positively correlated with the slope of the adhesive failure peak value.

5. The method for predicting the performance of adhesive-fitted joints as described in claim 1, characterized in that, The riveting performance of the tested adhesive riveting joint is predicted based on the second hump coordinate value of the double hump tensile curve. The horizontal axis of the second hump coordinate value is the riveting failure tensile displacement when the tested adhesive riveting joint begins to fail, and the vertical axis is the riveting failure load when the tested adhesive riveting joint begins to fail. The riveting performance of the tested adhesive riveting joint is positively correlated with the tensile displacement at riveting failure and the load at riveting failure, including: Based on the abscissa and ordinate of the second hump coordinate value of the double-hump tensile curve, the riveting failure tensile displacement and the riveting failure load at the point when the tested adhesive riveting joint begins to fail are determined respectively. If the tensile displacement of the riveting failure is not less than the preset minimum riveting failure displacement, and the load of the riveting failure is not less than the minimum load of the riveting failure, then the riveting performance of the tested adhesive riveting joint is determined to meet the preset riveting performance requirements. If the tensile displacement of the riveting failure is less than the preset minimum riveting failure displacement, and / or the riveting failure load is less than the minimum riveting failure load, then it is determined that the riveting performance of the tested adhesive riveting joint does not meet the preset riveting performance requirements.

6. The method for predicting the performance of adhesive-fitted joints as described in claim 5, characterized in that, If the tensile displacement due to riveting failure is less than the preset minimum riveting failure displacement, and / or the load due to riveting failure is less than the minimum load due to riveting failure, then the riveting performance of the tested adhesive riveting joint is determined to not meet the preset riveting performance requirements, including: If the tensile displacement of the riveting failure is less than the minimum riveting failure displacement, but the load of the riveting failure is not less than the minimum riveting failure load, then the riveting performance of the tested adhesive riveting joint is determined to be insufficient for either the rivet or the material being connected. If the tensile displacement of the riveting failure is not less than the minimum riveting failure displacement, but the riveting failure load is less than the minimum riveting failure load, then the riveting performance of the tested adhesive riveting joint is determined to be insufficient rivet clamping. If the tensile displacement of the riveting failure is less than the minimum riveting failure displacement, and the load of the riveting failure is less than the minimum riveting failure load, then the riveting performance of the tested adhesive riveting joint is determined to be that the rivet or the material being connected is inadequate and the rivet is not properly clamped.

7. The method for predicting the performance of adhesive-fitted joints as described in claim 1, characterized in that, A tensile test is performed on the adhesive riveting joint under test to obtain a double-hump tensile curve of the joint. The horizontal axis of the double-hump tensile curve represents the tensile displacement, and the vertical axis represents the load on the joint under test during tension. The test also includes: The product of the adhesive failure load and the first strength ratio is set as the upper limit of the adhesive ratio; the first strength ratio is a real number greater than 1 and less than 2. The product of the adhesive failure load and the second strength ratio is set as the lower limit of the adhesive ratio; the second strength ratio is a real number greater than 0 and less than 1. If the riveting failure load is less than the lower limit of the adhesive bonding ratio, then the tested adhesive-riveted joint is determined to be mainly supported by adhesive bonding. If the riveting failure load is not less than the lower limit of the adhesive bonding ratio and not greater than the upper limit of the adhesive bonding ratio, then the tested adhesive-riveted joint is determined to be supported by both adhesive bonding and riveting. If the riveting failure load is greater than the upper limit of the adhesive bonding ratio, then the tested adhesive-riveted joint is determined to be mainly supported by riveting.

8. The method for predicting the performance of adhesive-fitted joints as described in claim 1, characterized in that, The riveting performance of the tested adhesive riveting joint is predicted based on the second hump coordinate value of the double-hump tensile curve. The horizontal axis of the second hump coordinate value is the riveting failure tensile displacement when the tested adhesive riveting joint begins to fail, and the vertical axis is the riveting failure load of the tested adhesive riveting joint. Following this, the following is also included: The complete failure load of the adhesive joint under test is determined based on the double-hump tensile curve, and the complete failure load is the ordinate corresponding to the complete failure displacement. The peak slope of the riveting failure of the tested adhesive-bonded joint is determined based on the difference between the tensile displacement of the riveting failure and the displacement of the complete adhesive failure, as well as the difference between the riveting failure load and the load of the complete adhesive failure. The riveting stiffness of the tested adhesive riveting joint is determined based on the slope of the riveting failure peak value, and the riveting stiffness is positively correlated with the slope of the riveting failure peak value.

9. The method for predicting the performance of adhesive-fitted joints as described in claim 1, characterized in that, A tensile test is performed on the adhesive riveting joint under test to obtain a double-hump tensile curve of the joint. The horizontal axis of the double-hump tensile curve represents the tensile displacement, and the vertical axis represents the load on the joint under test during tension. The test also includes: The complete failure displacement of the riveting joint under test is determined based on the double-hump tensile curve. The complete failure displacement is the abscissa corresponding to the minimum value after the second hump coordinate value of the double-hump tensile curve in the positive direction. Calculate the second difference between the riveting failure displacement and the riveting failure tensile displacement; If the second difference is not greater than the preset maximum second difference, then it is determined that the riveting failure performance of the tested adhesive riveting joint meets the preset riveting failure performance requirements. If the second difference is greater than the preset maximum second difference, it is determined that the riveting failure performance of the tested adhesive riveting joint does not meet the preset riveting failure performance requirements, and that the compressive strength of the connected material is insufficient.

10. The method for predicting the performance of adhesive-fitted joints as described in any one of claims 1-9, characterized in that, The riveting performance of the tested adhesive riveting joint is predicted based on the second hump coordinate value of the double hump tensile curve. The horizontal axis of the second hump coordinate value is the riveting failure tensile displacement when the tested adhesive riveting joint begins to fail, and the vertical axis is the riveting failure load when the tested adhesive riveting joint begins to fail. After the riveting performance of the tested adhesive riveting joint is positively correlated with the riveting failure tensile displacement and the riveting failure load, the following is also included: The material failure load ratio is determined based on the connected material corresponding to the adhesive riveting joint under test; the material failure load ratio is a real number greater than 0 and less than 1. The product obtained by multiplying the riveting failure load by the material failure load ratio is set as the first product; To the right of the second hump coordinate value of the double-hump stretch curve, the horizontal coordinate corresponding to the product with the first hump as the vertical coordinate is set as the material failure displacement threshold value. If the third difference between the material failure displacement threshold value and the tensile displacement of the riveting failure is not greater than the preset displacement threshold value, then it is determined that the performance of the connected material corresponding to the tested adhesive riveting joint meets the preset requirements. If the third difference between the material failure displacement threshold value and the tensile displacement of the riveting failure is greater than the preset displacement threshold value, then it is determined that the performance of the connected material corresponding to the tested adhesive riveting joint does not meet the preset requirements, and the compressive strength of the connected material is insufficient.

11. A device for predicting the performance of a glued joint, characterized in that, include: Memory, used to store computer programs; A processor, configured to, when executing a computer program, implement the steps of the method for predicting the performance of a glued joint as described in any one of claims 1-10.

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