Method and device for predicting performance of rubber-riveted joint

Abstract

The invention discloses a rubber-riveted joint performance prediction method and device, and the method comprises the steps: obtaining a double-hump stretching curve of a to-be-tested rubber-riveted joint after the stretching test of the to-be-tested rubber-riveted joint, and carrying out the performance prediction of the to-be-tested rubber-riveted joint based on a horizontal coordinate and a vertical coordinate of a first hump coordinate value of the double-hump stretching curve, the glue joint failure tensile displacement and the glue joint failure load are used for predicting the glue joint performance of the to-be-tested glue joint when the to-be-tested glue joint begins to fail; and predicting the riveting performance of the to-be-tested rubber-riveted joint based on the horizontal coordinate and the vertical coordinate of the second hump coordinate value of the double-hump stretching curve, namely the riveting failure stretching displacement and the riveting failure load when the to-be-tested rubber-riveted joint begins to fail. According to the method, the double-hump stretching curve can be specifically used for respectively analyzing the glue joint failure and the riveting failure of the to-be-tested glue-riveted joint, so that the glue joint performance and the riveting performance are respectively determined, the glue joint mode and the riveting mode are respectively and specifically adjusted, and the connection stability of the to-be-tested glue-riveted joint is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of metal material performance testing, and in particular to a method and device for predicting the performance of a riveted joint. Background Art

[0002] Adhesive-riveted joints are created using a hybrid bonding technique that combines adhesive and rivets to create stronger, more reliable connections. They utilize the chemical reaction or physical solidification between the adhesive and the base material, along with the mechanical locking action of the rivet, to achieve a connection. Due to their strong adhesion, excellent sealing, strong corrosion resistance, ability to connect dissimilar materials, and excellent seismic performance, these joints are widely used in the automotive, aerospace, appliance, and construction industries.

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

[0004] The purpose of the present invention is to provide a method and device for predicting the performance of a glue-riveted joint, which can specifically analyze the glue-riveted joint to be tested when the glue fails and when the rivet fails through a double-hump tensile curve, thereby determining the performance of the glue and the performance of the rivet respectively, so as to make targeted adjustments to the glue method and the riveting method respectively, thereby improving the connection stability of the glue-riveted joint to be tested.

[0005] To solve the above technical problems, the present invention provides a method for predicting the performance of a glue-riveted joint, comprising:

[0006] Performing a tensile test on the riveted joint to be tested to obtain a double-hump tensile curve of the riveted joint to be tested, wherein the horizontal axis of the double-hump tensile curve represents the tensile displacement and the vertical axis represents the load of the riveted joint to be tested when being stretched;

[0007] The adhesive bonding performance of the adhesive riveted joint to be tested is predicted based on the coordinate value of the first hump of the double-hump tensile curve, wherein the abscissa of the first hump coordinate value is the adhesive failure tensile displacement when the adhesive riveted joint to be tested begins to fail, and the ordinate is the adhesive failure load when the adhesive riveted joint to be tested begins to fail; the adhesive bonding performance of the adhesive riveted joint to be tested is positively correlated with the adhesive failure tensile displacement and the adhesive failure load;

[0008] The riveting performance of the riveted joint to be tested 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 riveted joint to be tested begins to fail, and the ordinate is the riveting failure load when the riveted joint to be tested begins to fail; the riveting performance of the riveted joint to be tested is positively correlated with the riveting failure tensile displacement and the riveting failure load.

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

[0010] Determine the adhesive failure tensile displacement and the adhesive failure load when the adhesive riveted joint to be tested begins to fail based on the abscissa and ordinate of the first hump coordinate value of the double-hump tensile curve;

[0011] If the adhesive failure tensile displacement is not less than the preset minimum adhesive failure displacement, and the adhesive failure load is not less than the minimum adhesive failure load, it is determined that the adhesive performance of the adhesive-riveted joint to be tested meets the preset adhesive performance requirements;

[0012] 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, it is determined that the adhesive performance of the adhesive-riveted joint to be tested 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 determining that the adhesive performance of the adhesive-riveted joint to be tested does not meet the preset adhesive performance requirement includes:

[0014] If the adhesive failure tensile displacement is less than the minimum adhesive failure displacement, but the adhesive failure load is not less than the minimum adhesive failure load, it is determined that the adhesive performance of the adhesive-riveted joint to be tested is insufficient;

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

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

[0017] Preferably, a tensile test is performed on the rivet joint to be tested to obtain a double-hump tensile curve of the rivet joint to be tested, wherein the horizontal axis of the double-hump tensile curve is the tensile displacement and the vertical axis is the load of the rivet joint to be tested when being stretched, further comprising:

[0018] Determining a peak slope of adhesive failure of the adhesive-riveted joint to be tested based on the adhesive failure tensile displacement and the adhesive failure load;

[0019] The adhesive stiffness of the adhesive-riveted joint to be tested is determined based on the adhesive failure peak slope, and the adhesive stiffness is positively correlated with the adhesive failure peak slope.

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

[0021] Determine the rivet failure tensile displacement and the rivet failure load when the tested adhesive riveted joint begins to fail based on the abscissa and ordinate of the second hump coordinate value of the double-hump tensile curve;

[0022] If the rivet failure tensile displacement is not less than the preset minimum rivet failure displacement, and the rivet failure load is not less than the minimum rivet failure load, it is determined that the riveting performance of the tested adhesive riveted joint meets the preset riveting performance requirements;

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

[0024] Preferably, if the rivet failure tensile displacement is less than the preset minimum rivet failure displacement, and / or the rivet failure load is less than the minimum rivet failure load, determining that the riveting performance of the tested adhesive-riveted joint does not meet the preset riveting performance requirement includes:

[0025] If the rivet failure tensile displacement is less than the minimum rivet failure displacement, but the rivet failure load is not less than the minimum rivet failure load, it is determined that the riveting performance of the tested adhesive riveted joint is insufficient for the rivet or the connected material.

[0026] If the rivet failure tensile displacement is not less than the minimum rivet failure displacement, but the rivet failure load is less than the minimum rivet failure load, it is determined that the riveting performance of the tested adhesive riveted joint is insufficient rivet compression;

[0027] If the rivet failure tensile displacement is less than the minimum rivet failure displacement, and the rivet failure load is less than the minimum rivet failure load, it is determined that the riveting performance of the tested adhesive riveted joint is insufficient in performance of the rivet or the connected material and insufficient in compression of the rivet.

[0028] Preferably, a tensile test is performed on the rivet joint to be tested to obtain a double-hump tensile curve of the rivet joint to be tested, wherein the horizontal axis of the double-hump tensile curve is the tensile displacement and the vertical axis is the load of the rivet joint to be tested when being stretched, further comprising:

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

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

[0031] If the rivet failure load is less than the lower limit of the adhesive bonding ratio, it is determined that the adhesive bonding load of the adhesive-riveted joint to be tested is mainly carried by the adhesive bonding;

[0032] If the rivet failure load is not less than the lower limit of the bonding ratio and not greater than the upper limit of the bonding ratio, it is determined that the tested glue-riveted joint is loaded by both bonding and riveting;

[0033] If the rivet failure load is greater than the upper limit of the bonding ratio, it is determined that the tested glue-riveted joint is mainly loaded by riveting.

[0034] Preferably, a tensile test is performed on the rivet joint to be tested to obtain a double-hump tensile curve of the rivet joint to be tested, wherein the horizontal axis of the double-hump tensile curve is the tensile displacement and the vertical axis is the load of the rivet joint to be tested when being stretched, further comprising:

[0035] Determining the adhesive complete failure displacement of the adhesive riveted joint to be tested based on the double-hump tensile curve, wherein the adhesive 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 a first difference value obtained by subtracting the adhesive joint failure tensile displacement from the adhesive joint complete failure displacement;

[0037] If the first difference is 0, it is determined that the transition stability from adhesive failure to rivet load of the adhesive-riveted joint to be tested is an overstable transition from adhesive failure to rivet load;

[0038] If the first difference is greater than 0 and not greater than a preset maximum first difference, it is determined that the transition stability from adhesive failure to rivet load of the adhesive-riveted joint to be tested is a transition from adhesive failure to rivet load stability;

[0039] If the first difference is greater than the preset maximum first difference, it is determined that the transition stability from adhesive failure to rivet load of the adhesive-riveted joint to be tested is unstable;

[0040] Among them, the performance of the transition from adhesive failure to super-stable rivet load is better than the performance of the transition from adhesive failure to stable rivet load, and the performance of the transition from adhesive failure to stable rivet load is better than the performance of the transition from adhesive failure to unstable rivet load.

[0041] Preferably, the method further comprises: predicting the riveting performance of the tested adhesive riveted joint based on the coordinate value of the second hump 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 riveted joint begins to fail, and the ordinate is the riveting failure load of the tested adhesive riveted joint.

[0042] Determine the complete adhesive failure load of the adhesive riveted joint to be tested based on the double-hump tensile curve, where the complete adhesive failure load is the vertical coordinate corresponding to the complete adhesive failure displacement;

[0043] Determining a riveting failure peak slope of the adhesive-riveted joint to be tested based on a difference between the riveting failure tensile displacement and the adhesive complete failure displacement, and a difference between the riveting failure load and the adhesive complete failure load;

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

[0045] Preferably, a tensile test is performed on the rivet joint to be tested to obtain a double-hump tensile curve of the rivet joint to be tested, wherein the horizontal axis of the double-hump tensile curve is the tensile displacement and the vertical axis is the load of the rivet joint to be tested when being stretched, further comprising:

[0046] Determining the complete rivet failure displacement of the tested adhesive riveted joint based on the double-hump tensile curve, wherein the complete rivet failure displacement is the abscissa corresponding to the minimum value from the second hump coordinate value of the double-hump tensile curve in the positive direction;

[0047] Calculate a second difference value obtained by subtracting the rivet failure tensile displacement from the rivet complete failure displacement;

[0048] 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-riveted joint meets the preset riveting failure performance requirement;

[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 riveted joint does not meet the preset riveting failure performance requirements, and the compressive resistance of the connected materials is insufficient.

[0050] Preferably, the riveting performance of the tested adhesive riveted 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 riveted joint begins to fail, and the ordinate is the riveting failure load when the tested adhesive riveted joint begins to fail; after the riveting performance of the tested adhesive riveted joint is positively correlated with the riveting failure tensile displacement and the riveting failure load, the method further includes:

[0051] Determining a material failure load ratio based on the connected materials corresponding to the adhesive riveted joint to be tested; the material failure load ratio is a real number greater than 0 and less than 1;

[0052] setting a product obtained by multiplying the riveting failure load by the material failure load ratio as a first product;

[0053] On the right side of the second hump coordinate value of the double-hump tensile curve, the abscissa corresponding to the product of the second hump coordinate value and the first hump coordinate value is set as the material failure displacement threshold value;

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

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

[0056] In order to solve the above technical problems, the present invention also provides a device for predicting the performance of a glue-riveted joint, comprising:

[0057] memory for storing computer programs;

[0058] The processor is configured to implement the steps of the method for predicting the performance of adhesive-riveted joints as described above when executing the computer program.

[0059] The present application provides a method and device for predicting the performance of a riveted joint. After a tensile test is performed on the riveted joint to be tested, a double-hump tensile curve of the riveted joint to be tested is obtained. The bonding performance of the riveted joint to be tested is predicted based on the horizontal coordinate and vertical coordinate of the first hump coordinate value of the double-hump tensile curve, that is, the tensile displacement of the bonding failure and the load of the bonding failure when the riveted joint to be tested begins to fail; the riveting performance of the riveted joint to be tested is predicted based on the horizontal coordinate and vertical coordinate of the second hump coordinate value of the double-hump tensile curve, that is, the tensile displacement of the rivet failure and the load of the rivet failure when the riveted joint to be tested begins to fail. Specifically, the double-hump tensile curve can be used to analyze the riveted joint to be tested at the time of bonding failure and at the time of rivet failure, thereby determining the bonding performance and the riveting performance respectively, so as to make targeted adjustments to the bonding method and the riveting method respectively, thereby improving the connection stability of the riveted joint to be tested. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] In order to more clearly illustrate the embodiments of the present invention, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0061] Figure 1 A schematic flow chart of a method for predicting performance of a glue-riveted joint provided by the present invention;

[0062] Figure 2 A schematic diagram of a glue rivet joint provided by the present invention connecting connected materials;

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

[0064] Figure 4 A schematic diagram of adhesive failure and riveting failure limits provided by the present invention;

[0065] Figure 5 A schematic diagram of bonding performance prediction provided by the present invention;

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

[0067] Figure 7 A schematic diagram of a double-hump tensile curve for an example of performance prediction of a tested adhesive riveted joint provided by the present invention;

[0068] Figure 8 A schematic structural diagram of a system for predicting the performance of adhesive-riveted joints provided by the present invention;

[0069] Figure 9This is a schematic structural diagram of a device for predicting the performance of a riveted joint provided by the present invention. DETAILED DESCRIPTION

[0070] The core of the present invention is to provide a method and device for predicting the performance of glue-riveted joints, which can specifically analyze the glue-riveted joint to be tested when the glue fails and when the rivet fails through the double-hump tensile curve, thereby determining the performance of the glue and the performance of the rivet respectively, so as to make targeted adjustments to the glue method and the riveting method respectively, thereby improving the connection stability of the glue-riveted joint to be tested.

[0071] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0072] Please refer to Figure 1 , Figure 1 A schematic flow chart of a method for predicting the performance of a rivet joint provided by the present invention, the method comprising:

[0073] S11: Performing a tensile test on the tested adhesive riveted joint to obtain a double-hump tensile curve of the tested adhesive riveted joint, wherein the horizontal axis of the double-hump tensile curve represents the tensile displacement, and the vertical axis represents the load of the tested adhesive riveted joint when being stretched;

[0074] Adhesive bonding is a process that uses the mechanical bonding force, physical adsorption force and chemical bonding force generated by the adhesive on the connection surface to connect two adhesive parts. Adhesive bonding is not only suitable for connecting the same materials, but also for connecting dissimilar materials. The adhesive bonding process is simple and does not require complex process equipment. The adhesive bonding operation does not need to be carried out under high temperature and high pressure, so the adhesive parts are not easily deformed and the stress distribution of the joint is uniform. Under normal circumstances, adhesive joints have good sealing, electrical insulation and corrosion resistance. Riveting is a mechanical term that uses axial force to thicken the nail rod in the rivet hole of the part and form a nail head to connect multiple parts. Adhesive riveting is a composite connection technology of adhesive bonding and riveting. Adhesive riveted joints are adhesive joints that use both adhesive bonding and riveting. Adhesive riveted joints are mainly adhesive bonding, and rivets are used to improve the uneven pull-off strength and peel strength of the joint. The rivets can be driven before the adhesive is cured and then cured, or they can be installed after the adhesive is cured. Adhesive riveted joints are simple and feasible, have good mechanical properties, and are also suitable for connecting large-area parts. Please refer to Figure 2 , Figure 2This is a schematic diagram of a glue-riveted joint provided by the present invention for connecting connected materials. There is a glue layer between rivet material 1 and material 2, the glue layer thickness is less than 1mm, and the rivet rivets material 1 and material 2 together.

[0075] Since glue-riveted joints are usually used in the fields of machinery manufacturing or aircraft manufacturing, the performance requirements for glue-riveted joints are high. Therefore, it is necessary to predict the performance of glue-riveted joints. In the prior art, when predicting the performance of glue-riveted joints, it is common to perform a tensile test on the glue-riveted joints, that is, to install the glue-riveted joint to be tested on the fixture of the tensile testing machine to ensure that the glue-riveted joint to be tested can be stably stressed during the stretching process. The installation of the glue-riveted joint to be tested should ensure that its axis is consistent with the center line of force application to avoid eccentric force. By applying force to the glue-riveted joint to be tested and observing when the glue-riveted joint to be tested fails, the overall performance of the glue-riveted joint to be tested is determined based on the overall failure state of the glue-riveted joint to be tested. However, since the glue-riveted joint to be tested is a joint that is compositely connected by gluing and riveting, after determining the overall performance of the glue-riveted joint to be tested, if the performance cannot meet the requirements, it is only possible to try to adjust the riveting method or the gluing method separately and re-determine the performance of the glue-riveted joint to be tested. Since there are many types of gluing and riveting methods, if the gluing performance and riveting performance of the glue-riveted joint to be tested cannot be determined respectively, it is impossible to accurately adjust the glue-riveted joint to be tested.

[0076] In order to solve the above technical problems, in this application, when predicting the performance of the rivet joint to be tested, a tensile test is also performed on the rivet joint to be tested. However, in the process of the tensile test, the load and displacement of the rivet joint to be tested from the beginning of stretching to complete destruction are recorded, and the load-displacement curve of the rivet joint to be tested in the tensile test is determined by the load and displacement in the entire process, that is, the double-hump tensile curve. The horizontal axis of the double-hump tensile curve is the tensile displacement, and the vertical axis is the load of the rivet joint to be tested.

[0077] Among them, since the glue-riveted joint to be tested is a joint connected by bonding and riveting, in the process of the glue-riveted joint to be tested being stretched, the glue first receives the force, that is, starting from the displacement of 0, the ordinate of the double-hump tensile curve first increases with the increase of the abscissa, that is, the bonding load of the glue-riveted joint to be tested increases with the increase of displacement. When the bonding load reaches the first maximum value, that is, the first hump of the double-hump tensile curve, the glue-riveted joint to be tested begins to fail, and then the bonding load decreases with the increase of displacement until the first minimum value, and the bonding of the glue-riveted joint to be tested completely fails. At this time, the riveting starts to bear force, and the ordinate of the double-hump tensile curve increases with the increase of displacement, that is, the riveting load increases with the increase of displacement. When the riveting load reaches the maximum value, that is, the second hump of the double-hump tensile curve, the riveting begins to fail, and then the riveting load decreases with the increase of displacement until the riveting load no longer changes and 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, wherein the horizontal axis is displacement, represented by the letter X, and the unit is mm; the vertical axis is load, represented by the letter F, and the unit is KN; point o is the point where the tensile test starts, and the coordinates are the origin. At this time, only the adhesive joint bears the load; point a is the first hump, that is, the adhesive joint begins to fail, the horizontal axis is the tensile displacement at adhesive joint failure, and the vertical axis is the point corresponding to the adhesive joint failure load; oa is the adhesive load-bearing stage, that is, the adhesive joint load-bearing stage; point b is the point where the adhesive joint completely fails, and from this point on, the riveting joint bears the load; ob is the adhesive joint failure process ; ab is interlaminar cracking failure, that is, failure occurs inside the connected material, the fiber matrix breaks and delaminates, among which, the interface failure behavior of the riveted joint is different under different riveted materials; point c is the second hump, that is, the riveting begins to fail, the horizontal axis is the riveting failure tensile displacement, and the vertical axis is the point corresponding to the riveting failure load; bc is the stage where the rivet begins to bear the load; point d is the complete riveting failure, that is, the point where the entire riveted joint to be tested fails completely, and the rivet head is separated from the connected material; cd is the stage where the rivet head begins to be pulled off; bd is the riveting failure process.

[0079] S12: Predicting the bonding performance of the adhesive-riveted joint to be tested based on the coordinate value of the first hump of the double-hump tensile curve, where the abscissa of the first hump coordinate value is the tensile displacement at which the adhesive-riveted joint to be tested begins to fail, and the ordinate is the load at which the adhesive-riveted joint to be tested begins to fail. The bonding performance of the adhesive-riveted joint to be tested is positively correlated with the tensile displacement at which the adhesive-riveted joint to be tested begins to fail and the load at which the adhesive-riveted joint to be tested begins to fail.

[0080] Since the first hump of the double-hump tensile curve is the coordinate value corresponding to the bonding failure tensile displacement and the bonding failure load when the bonding of the riveted joint to be tested begins to fail, the bonding performance can be predicted based on the horizontal and vertical coordinates of the first hump. Specifically, the larger the bonding failure tensile displacement and the bonding failure load, the better the bonding performance of the riveted joint to be tested. Based on this, it can be determined whether the bonding performance of the riveted joint to be tested meets the requirements based on the coordinate value of the first hump of the double-hump tensile curve.

[0081] After determining the bonding performance, if the user is not satisfied with the bonding performance of the tested adhesive-riveted joint, the user can adjust the bonding method of the tested adhesive-riveted joint. For example, there are many bonding methods, such as threaded connection, flange connection, and clamp connection.

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

[0083] Since the second hump of the double-hump tensile curve is the coordinate value corresponding to the rivet failure tensile displacement and the rivet failure load when the riveting of the riveted joint to be tested begins to fail, the riveting performance can be predicted based on the horizontal and vertical coordinates of the second hump. Specifically, the larger the rivet failure tensile displacement and the rivet failure load, the better the riveting performance of the riveted joint to be tested. Based on this, it can be determined whether the riveting performance of the riveted joint to be tested meets the requirements based on the coordinate value of the second hump 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 riveted joint, the riveting method 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 the upper limit of the adhesive failure load and the upper limit of the riveted failure load are not limited in this application. The greater the load that the adhesive-riveted joint to be tested can bear, the better its performance.

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

[0087] In summary, in this embodiment, the double-hump tensile curve can be used to analyze the adhesive failure and riveting failure of the adhesive-riveted joint to be tested respectively, so as to determine the adhesive performance and the riveting performance 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-riveted joint to be tested.

[0088] Based on the above embodiment:

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

[0090] The adhesive failure tensile displacement and adhesive failure load of the adhesive riveted joint to be tested when it begins to fail are determined based on the abscissa and ordinate of the first hump coordinate value of the double-hump tensile curve.

[0091] If the adhesive failure tensile displacement 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 it is determined that the adhesive performance of the adhesive-riveted joint to be tested meets the preset adhesive performance requirements;

[0092] If the bonding failure tensile displacement is less than the preset minimum bonding failure displacement, and / or the bonding failure load is less than the minimum bonding failure load, it is determined that the bonding performance of the tested adhesive-riveted joint does not meet the preset bonding performance requirements.

[0093] When determining the bonding performance of the riveted joint to be tested, specifically, the bonding performance of the riveted joint to be tested 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, it is possible to determine whether the bonding performance meets the preset bonding performance requirements according to the coordinate value of the first hump of the double-hump tensile curve, thereby determining whether it is necessary to adjust the bonding method of the riveted joint to be tested to improve the overall performance of the riveted joint to be tested.

[0094] Please refer to Figure 4 , Figure 4 A schematic diagram of adhesive failure and riveting failure limits provided by the present invention.

[0095] The minimum adhesive failure displacement and the minimum adhesive failure load may be, but are not limited to, set based on the type of connected materials or the application scenario requirements of the adhesive-riveted joint to be tested.

[0096] As a preferred embodiment, if the adhesive failure tensile displacement is less than a 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 adhesive-riveted joint to be tested does not meet the preset adhesive performance requirements, including:

[0097] If the tensile displacement at 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-riveted joint is determined to be insufficient;

[0098] If the tensile displacement at 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 adhesive-riveted joint to be tested is determined to be insufficient strength of the adhesive layer interface;

[0099] If the tensile displacement at 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 riveted joint is determined to be insufficient adhesive performance and insufficient adhesive layer bonding surface strength.

[0100] In this embodiment, the specific situation when the bonding performance of the tested adhesive-riveted joint does not meet the preset bonding performance requirements is classified, that is, the specific reason causing the bonding performance of the tested adhesive-riveted joint to not meet the preset bonding performance requirements is determined.

[0101] Specifically, if only the tensile displacement of the bonding failure is less than the minimum bonding failure displacement, but the bonding failure load is not less than the minimum bonding failure load, at this time, when the tensile displacement of the bonded riveted joint to be tested is small, the bonding of the bonded riveted joint to be tested begins to fail. Since the load of the bonded riveted joint to be tested is still not less than the minimum bonding failure load at this time, it can be determined that the bonding performance of the bonded riveted joint to be tested at this time is insufficient adhesive performance, that is, insufficient viscosity of the adhesive, resulting in the bonding method of the bonded riveted joint to be tested being unable to withstand a large tensile displacement, or the displacement is too short and the adhesive performance is insufficient.

[0102] If the tensile displacement of the 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 when the adhesive-riveted joint to be tested is stretched, its load is small. Since the displacement of the adhesive-riveted joint to be tested is still not less than the minimum adhesive failure displacement at this time, it can be determined that the adhesive performance of the adhesive-riveted joint to be tested at this time is insufficient strength of the adhesive layer bonding surface, that is, the adhesive layer bonding surface strength is low and easy to crack. At this time, the adhesive strength of the adhesive layer bonding surface of the adhesive-riveted joint to be tested is insufficient and can be easily pulled to crack.

[0103] If not only the tensile displacement of the bonding failure is less than the minimum bonding failure displacement, but also the bonding failure load is less than the minimum bonding failure load, then when the tested riveted joint is stretched, not only is the tensile displacement it can withstand smaller, but the load is also smaller. Since the displacement of the tested riveted joint is still not less than the minimum bonding failure displacement, it can be determined that the bonding performance of the tested riveted joint at this time is insufficient due to insufficient adhesive performance and insufficient strength of the adhesive layer bonding surface, that is, the adhesive performance and the bonding surface performance lead to the bonding performance not meeting the requirements.

[0104] Based on this, after specifically determining why the bonding performance of the glue-riveted joint to be tested 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 glue-riveted joint to be tested.

[0105] Please refer to Table 1:

[0106] Table 1 Adhesive performance prediction correspondence table

[0107]

[0108] in, is the bond failure load, is the tensile displacement at bond failure, is the minimum bond failure load, is the minimum adhesive failure displacement.

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

[0110] As a preferred embodiment, a tensile test is performed on the rivet joint to be tested to obtain a double-hump tensile curve of the rivet joint to be tested, wherein the horizontal axis of the double-hump tensile curve is the tensile displacement and the vertical axis is the load of the rivet joint to be tested when being stretched, further comprising:

[0111] Determine the peak slope of adhesive failure of the adhesive-riveted joint to be tested based on the adhesive failure tensile displacement and adhesive failure load;

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

[0113] In this embodiment, the slope of the double-hump stretching curve before the first hump can also be used, that is, Figure 5 k1 in the figure is used to determine the peak slope of the adhesive failure of the adhesive-riveted joint to be tested. The larger the peak slope of the adhesive failure, the greater the adhesive stiffness and the stronger the ability of the adhesive material to resist elastic deformation when subjected to stress.

[0114] As a preferred embodiment, the riveting performance of the tested adhesive riveted 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 riveted joint begins to fail, and the ordinate is the riveting failure load when the tested adhesive riveted joint begins to fail; the riveting performance of the tested adhesive riveted joint is positively correlated with the riveting failure tensile displacement and the riveting failure load, including:

[0115] The horizontal coordinate and vertical coordinate of the second hump coordinate value of the double hump tensile curve are used to respectively determine the riveting failure tensile displacement and the riveting failure load when the tested adhesive riveted joint begins to fail;

[0116] If the rivet failure tensile displacement is not less than the preset minimum rivet failure displacement, and the rivet failure load is not less than the minimum rivet failure load, it is determined that the riveting performance of the tested adhesive riveted joint meets the preset riveting performance requirements;

[0117] If the rivet failure tensile displacement is less than the preset minimum rivet failure displacement, and / or the rivet failure load is less than the minimum rivet failure load, it is determined that the riveting performance of the tested adhesive riveted joint does not meet the preset riveting performance requirements.

[0118] When determining the riveting performance of the glue-riveted joint to be tested, specifically, the riveting performance of the glue-riveted joint to be tested meets the preset riveting performance only when the riveting failure tensile displacement is not less than the preset minimum riveting failure displacement and the riveting failure load is not less than the minimum riveting failure load. Based on this, it is possible to determine whether the riveting performance meets the preset riveting performance requirements according to the coordinate value of the second hump of the double-hump tensile curve, thereby determining whether it is necessary to adjust the riveting method of the glue-riveted joint to be tested to improve the overall performance of the glue-riveted joint to be tested.

[0119] The minimum riveting failure displacement and the minimum riveting failure load may be, but are not limited to, set based on the type of connected materials or the application scenario requirements of the adhesive riveted joint to be tested.

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

[0121] If the rivet failure tensile displacement is less than the minimum rivet failure displacement, but the rivet failure load is not less than the minimum rivet failure load, it is determined that the riveting performance of the tested adhesive riveted joint is insufficient for the rivet or the connected material.

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

[0123] If the rivet failure tensile displacement is less than the minimum rivet failure displacement, and the rivet failure load is less than the minimum rivet failure load, it is determined that the riveting performance of the tested adhesive riveted joint is insufficient for the rivet or the connected material and the rivet is not tightened enough.

[0124] In this embodiment, the specific situation when the riveting performance of the tested glue-riveted joint does not meet the preset riveting performance requirements is classified, that is, the specific reason causing the riveting performance of the tested glue-riveted joint to not meet the preset riveting performance requirements is determined.

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

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

[0127] If not only the rivet failure tensile displacement is less than the minimum rivet failure displacement, but also the rivet failure load is less than the minimum rivet failure load, it means that when the riveted joint to be tested is stretched, not only the tensile displacement it can withstand is small, but also the load is small. Since the displacement of the riveted joint to be tested is still not less than the minimum rivet failure displacement, it can be determined that the riveting performance of the riveted joint to be tested at this time is insufficient performance of the rivet or the connected material and insufficient compression of the rivet.

[0128] Based on this, after specifically determining why the riveting performance of the glue-riveted joint to be tested 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 glue-riveted joint to be tested.

[0129] Please refer to Table 2:

[0130] Table 2 Riveting performance prediction correspondence table

[0131]

[0132] in, is the riveting failure load, is the tensile displacement of the riveted joint at failure, is the minimum riveting failure load, is the minimum riveting failure displacement.

[0133] Please refer to Figure 6 , Figure 6 A schematic diagram of riveting performance prediction provided by the present invention.

[0134] As a preferred embodiment, a tensile test is performed on the rivet joint to be tested to obtain a double-hump tensile curve of the rivet joint to be tested, wherein the horizontal axis of the double-hump tensile curve is the tensile displacement and the vertical axis is the load of the rivet joint to be tested when being stretched, further comprising:

[0135] The contribution of bonding performance and riveting performance to the tested adhesive-riveted joint is predicted based on the bonding failure load and riveting failure load.

[0136] In this embodiment, not only the bonding performance and riveting performance of the tested glue-riveted joint are predicted respectively, but also the bonding performance contribution and riveting performance contribution of the tested glue-riveted joint are predicted, that is, it is determined whether the load in the tested glue-riveted joint is mainly borne by bonding or by riveting, so as to adjust the bonding and riveting in a targeted manner.

[0137] As a preferred embodiment, the contribution of the adhesive bonding performance and the riveting performance of the adhesive-riveted joint to be tested is predicted based on the adhesive bonding failure load and the riveting failure load, including:

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

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

[0140] If the riveting failure load is less than the lower limit of the adhesive ratio, it is determined that the adhesive-riveted joint to be tested is mainly loaded by the adhesive;

[0141] If the riveting failure load is not less than the lower limit of the bonding ratio and not greater than the upper limit of the bonding ratio, it is determined that the tested adhesive-riveted joint is loaded by both bonding and riveting;

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

[0143] In this embodiment, the bonding strength is used as the limit, and the upper limit and lower limit of the bonding ratio are set based on the bonding failure load. If the rivet failure load is between the lower limit and the upper limit of the bonding ratio, the bonding and riveting of the tested adhesive-riveted joint are of equal strength matching, indicating that the tested adhesive-riveted joint is loaded by both bonding and riveting, and is mainly used in the connection of medium-strength structural parts.

[0144] If the rivet failure load is less than the lower limit of the adhesive ratio, the adhesive-rivet low strength ratio is matched, the joint is loaded by the adhesive and supplemented by the rivet, and is mainly used in the connection of low-strength thin-walled parts.

[0145] If the rivet failure load is greater than the upper limit of the bonding ratio, the glue rivet is highly strength matched, and the tested glue-riveted joint is mainly loaded by rivets, supplemented by bonding. The adhesive bonding mainly plays the role of sealing and potential isolation, and is mainly used in the connection of high-strength structural parts.

[0146] Specifically, the first strength ratio can be 120%, and the upper limit of the bonding ratio is the bonding failure load multiplied by 120%; the second strength ratio can be 90%, that is, the lower limit of the bonding ratio is the bonding failure load multiplied by 90%; among them, the first strength ratio and the second strength ratio can be determined according to the actual application scenario of the glue-riveted joint to be tested.

[0147] Please refer to Figure 3 :

[0148] Table 3. Corresponding table of glue riveting contribution prediction

[0149]

[0150] As a preferred embodiment, a tensile test is performed on the rivet joint to be tested to obtain a double-hump tensile curve of the rivet joint to be tested, wherein the horizontal axis of the double-hump tensile curve is the tensile displacement and the vertical axis is the load of the rivet joint to be tested when being stretched, further comprising:

[0151] Determine the adhesive complete failure displacement of the adhesive riveted joint to be tested based on the double-hump tensile curve, where the adhesive 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 from adhesive failure to rivet bearing of the adhesive-riveted joint to be tested is determined based on the difference between the tensile displacement at adhesive failure and the displacement at complete adhesive failure.

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

[0154] As a preferred embodiment, determining the transition stability from adhesive failure to rivet bearing of the adhesive-riveted joint to be tested based on the difference between the adhesive failure tensile displacement and the adhesive complete failure displacement includes:

[0155] Calculate the first difference between the adhesive joint complete failure displacement and the adhesive joint failure tensile displacement;

[0156] If the first difference is 0, it is determined that the transition stability from adhesive failure to rivet load of the adhesive-riveted joint to be tested is an overstable 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, it is determined that the transition stability between adhesive failure and rivet load of the adhesive-riveted joint to be tested is a transition from adhesive failure to rivet load stability;

[0158] If the first difference is greater than the preset maximum first difference, it is determined that the transition stability from adhesive failure to rivet load of the adhesive-riveted joint to be tested is unstable;

[0159] Among them, the performance of the transition from adhesive failure to super-stable rivet load is better than the performance of the transition from adhesive failure to stable rivet load, and the performance of the transition from adhesive failure to stable rivet load is better than the performance of the transition from adhesive failure to unstable rivet load.

[0160] In this embodiment, if the first difference is 0, that is, the moment the adhesive begins to fail, the rivet begins to bear the load, and at this time there is an ultra-stable transition from adhesive failure to rivet bearing; if the first difference is greater than 0 and not greater than the preset maximum first difference, then after the adhesive begins to fail, it will take a period of displacement, but when the displacement does not exceed the preset maximum first difference, the rivet begins to bear the load. At this time, although there is a stable transition from adhesive failure to rivet bearing, its stability is still not as good as the transition stability from adhesive failure to rivet bearing when the first difference is 0; if the first difference is greater than the preset maximum first difference, then after the adhesive begins to fail, it will take a very long time before the rivet 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, after the adhesive begins to fail, the connected material has been pulled to deformation before the rivet begins to bear the load. At this time, the stability is poor.

[0161] Please refer to Table 4:

[0162] Table 4 Corresponding table of adhesive failure stability judgment

[0163]

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

[0165] As a preferred embodiment, the riveting performance of the tested adhesive riveted 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 riveted joint begins to fail, and the ordinate is the riveting failure load of the tested adhesive riveted joint, further comprising:

[0166] Determine the complete adhesive failure load of the adhesive-riveted joint to be tested based on the double-hump tensile curve, where the complete adhesive failure load is the vertical coordinate corresponding to the complete adhesive failure displacement;

[0167] Determine the peak slope of the riveted joint to be tested based on the difference between the tensile displacement at riveting failure and the displacement at complete adhesive failure, and the difference between the riveting failure load and the load at complete adhesive failure;

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

[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 riveted joint to be tested. If the peak slope of the riveted joint failure is larger, the riveted stiffness is larger, and the riveted material has a stronger ability to resist elastic deformation when subjected to stress. Figure 6 k2 in .

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

[0171] As a preferred embodiment, a tensile test is performed on the rivet joint to be tested to obtain a double-hump tensile curve of the rivet joint to be tested, wherein the horizontal axis of the double-hump tensile curve is the tensile displacement and the vertical axis is the load of the rivet joint to be tested when being stretched, further comprising:

[0172] Determine the complete rivet failure displacement of the tested adhesive riveted joint based on the double-hump tensile curve, where the complete rivet failure displacement is the horizontal coordinate corresponding to the minimum value after the second hump coordinate value of the double-hump tensile curve moves in the positive direction;

[0173] Calculate the second difference between the riveted complete failure displacement and the riveted failure tensile displacement;

[0174] 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-riveted joint meets 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 riveted joint does not meet the preset riveting failure performance requirements, and the compressive performance of the connected materials is insufficient.

[0176] In this embodiment, if the second difference is not greater than the preset maximum second difference, it is determined that the rivet failure performance of the tested adhesive-riveted joint meets the preset rivet failure performance requirements, mainly manifested in rivet shearing, pull-out, or tearing failure modes, and the compressive loss resistance of the connected material is within an acceptable range, that is, the cause of the rivet failure is the rivet being pulled off or pulled out. If the second difference is greater than the preset maximum second difference, it is determined that the rivet failure performance of the tested adhesive-riveted joint does not meet the preset rivet failure performance requirements, the main deformation is tearing, and the compressive loss resistance of the connected material does not meet the requirements. In other words, when the rivet completely fails, it is actually because the connected material has undergone significant deformation, such as being pulled out to form a large hole, and the rivet can no longer withstand the load. At this time, the connected material can be adjusted.

[0177] As a preferred embodiment, the riveting performance of the tested adhesive riveted 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 riveted joint begins to fail, and the ordinate is the riveting failure load when the tested adhesive riveted joint begins to fail; after the riveting performance of the tested adhesive riveted joint is positively correlated with the riveting failure tensile displacement and the riveting failure load, the method further includes:

[0178] Determine the material failure load ratio based on the connected materials corresponding to the adhesive riveted joint to be tested; 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] On the right side of the second hump coordinate value of the double hump tensile curve, the abscissa corresponding to the product of the second hump coordinate value and the first hump coordinate value is set as the material failure displacement threshold value;

[0181] If the third difference between the material failure displacement threshold value and the rivet failure tensile displacement is not greater than the preset displacement threshold value, it is determined that the performance of the connected material corresponding to the tested adhesive riveted joint meets the preset requirements;

[0182] If the third difference between the material failure displacement threshold value and the rivet failure tensile displacement is greater than the preset displacement threshold value, it is determined that the performance of the connected material corresponding to the tested rivet joint does not meet the preset requirements, and the compressive loss resistance 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 by determining the displacement and load of the rivet during the failure process after it is determined that the rivet has begun to fail. Specifically, it can be based on the first product obtained by multiplying the rivet failure load by the material failure load ratio. The vertical coordinate of the double-hump tensile curve corresponding to the first product is the load from the beginning of failure to complete failure of the rivet joint to be tested. It is a load selected according to the connected material connected to the rivet joint to be tested, and its tensile displacement is determined when the load of the rivet joint to be tested is the first product. The tensile displacement here is the tensile displacement during the rivet failure process; the third difference is obtained by subtracting the rivet failure tensile displacement from the material failure displacement threshold value. If the third difference is not greater than the preset displacement threshold value, it means that the rivet joint to be tested is loaded. When the load is the first product, the material failure displacement threshold is small, that is, the displacement after the rivet begins to fail is small. At this time, the connected material has better compressive loss resistance and is not easy to deform and damage; if the third difference is greater than the preset displacement threshold, it means that when the load borne by the rivet joint to be tested is the first product, the material failure displacement threshold is large, that is, the displacement after the rivet begins to fail is large. At this time, the connected material has poor compressive loss resistance and is easy to deform and damage. For example, when the rivet is stretched to a large displacement, the load it bears is not large, but a larger hole is pulled out of the connected material, 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, is the third difference, is the preset maximum third difference, is the material failure load ratio.

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

[0189] Table 6 Corresponding table of performance test examples of the tested adhesive riveted joints

[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, and the adhesive failure tensile displacement of sample 1 is 1.3mm, 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 1, so it is determined that the transition stability between adhesive failure and rivet bearing of sample 1 is a stable transition from adhesive failure to rivet bearing; the rivet failure load is 19.69, which is greater than the minimum rivet failure load of 16.5, and the rivet failure tensile displacement of sample 1 is 4.4, which is greater than the minimum rivet 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 value 8, it is determined that the performance of the connected material corresponding to sample 1 meets the preset requirements.

[0192] The bonding failure load of sample 2 is 3.95, which is less than the minimum bonding failure load of 8.0, and the bonding failure tensile displacement is 0.52, which is less than the minimum bonding failure displacement of 1.0. Therefore, it can be determined that sample 2 does not meet the preset bonding performance requirements, and it is determined that the bonding performance of sample 2 is caused by the adhesive performance and the bonding surface performance, which leads to the bonding performance not meeting the requirements; the first difference is 0.4, which is greater than 0 and less than the preset maximum first difference 1, so it is determined that the transition stability between bonding failure and rivet bearing of sample 2 is a stable transition from bonding failure to rivet bearing; the rivet failure load is 17.88, which is greater than the minimum rivet failure load of 16.5, and the rivet failure tensile displacement of sample 1 is 4.6, which is greater than the minimum rivet 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 value 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 rivet failure are the coordinates corresponding to the rivet failure load and the rivet failure tensile displacement, and the rivet failure limit coordinates are the coordinates corresponding to the minimum rivet failure load and the minimum rivet failure displacement.

[0194] Please refer to Figure 8 , Figure 8 This is a schematic diagram of the structure of a performance prediction system for adhesive riveted joints provided by the present invention, the system comprising:

[0195] The curve acquisition unit 81 is used to perform a tensile test on the rivet joint to be tested to obtain a double-hump tensile curve of the rivet joint to be tested, wherein the horizontal axis of the double-hump tensile curve is the tensile displacement and the vertical axis is the load of the rivet joint to be tested when being stretched;

[0196] The adhesive bonding testing unit 82 is configured to predict the adhesive bonding performance of the adhesive-riveted joint to be tested based on the coordinate value of the first hump of the double-hump tensile curve, wherein the abscissa of the first hump coordinate value is the adhesive failure tensile displacement when the adhesive-riveted joint to be tested begins to fail, and the ordinate is the adhesive failure load when the adhesive-riveted joint to be tested begins to fail; the adhesive bonding performance of the adhesive-riveted joint to be tested is positively correlated with the adhesive failure tensile displacement and the adhesive failure load;

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

[0198] For an introduction to the performance prediction system for adhesive riveted joints provided by the present invention, please refer to the above method embodiment, and the present invention will not be described in detail here.

[0199] Please refer to Figure 9 , Figure 9 This is a schematic diagram of the structure of a device for predicting the performance of a riveted joint provided by the present invention, the device comprising:

[0200] Memory 91, for storing computer programs;

[0201] The processor 92 is configured to implement the steps of the aforementioned method for predicting the performance of adhesive-riveted joints when executing the computer program.

[0202] For an introduction to the performance prediction device for rivet joints provided by the present invention, please refer to the above method embodiment, and the present invention will not be described in detail here.

[0203] It should also be noted that, in this specification, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

[0204] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present 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 present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for predicting the performance of a riveted joint, characterized in that: include: Performing a tensile test on the riveted joint to be tested to obtain a double-hump tensile curve of the riveted joint to be tested, wherein the horizontal axis of the double-hump tensile curve represents the tensile displacement and the vertical axis represents the load of the riveted joint to be tested when being stretched; The adhesive bonding performance of the adhesive riveted joint to be tested is predicted based on the coordinate value of the first hump of the double-hump tensile curve, wherein the abscissa of the first hump coordinate value is the adhesive failure tensile displacement when the adhesive riveted joint to be tested begins to fail, and the ordinate is the adhesive failure load when the adhesive riveted joint to be tested begins to fail; the adhesive bonding performance of the adhesive riveted joint to be tested is positively correlated with the adhesive failure tensile displacement and the adhesive failure load; The riveting performance of the riveted joint to be tested 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 riveted joint to be tested begins to fail, and the ordinate is the riveting failure load when the riveted joint to be tested begins to fail; the riveting performance of the riveted joint to be tested is positively correlated with the riveting failure tensile displacement and the riveting failure load.

2. The method for predicting the performance of a glue-riveted joint according to claim 1, wherein: Predicting the bonding performance of the adhesive-riveted joint to be tested based on the coordinate value of the first hump of the double-hump tensile curve, wherein the abscissa of the first hump coordinate value is the adhesive failure tensile displacement when the adhesive-riveted joint to be tested begins to fail, and the ordinate is the adhesive failure load when the adhesive-riveted joint to be tested begins to fail; The bonding performance of the adhesive riveted joint to be tested is positively correlated with the bonding failure tensile displacement and the bonding failure load, including: Determine the adhesive failure tensile displacement and the adhesive failure load when the adhesive riveted joint to be tested begins to fail based on the abscissa and ordinate of the first hump coordinate value of the double-hump tensile curve; If the adhesive failure tensile displacement is not less than the preset minimum adhesive failure displacement, and the adhesive failure load is not less than the minimum adhesive failure load, it is determined that the adhesive performance of the adhesive-riveted joint to be tested meets the preset adhesive performance requirements; 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, it is determined that the adhesive performance of the adhesive-riveted joint to be tested does not meet the preset adhesive performance requirements.

3. The method for predicting the performance of a glue-riveted joint according to claim 2, wherein: 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 determining that the adhesive performance of the adhesive-riveted joint to be tested does not meet the preset adhesive performance requirements includes: If the adhesive failure tensile displacement is less than the minimum adhesive failure displacement, but the adhesive failure load is not less than the minimum adhesive failure load, it is determined that the adhesive performance of the adhesive-riveted joint to be tested is insufficient; If the adhesive failure tensile displacement is not less than the minimum adhesive failure displacement, but the adhesive failure load is less than the minimum adhesive failure load, then it is determined that the adhesive performance of the adhesive-riveted joint to be tested is insufficient adhesive layer bonding surface strength; If the bonding failure tensile displacement is less than the minimum bonding failure displacement, and the bonding failure load is less than the minimum bonding failure load, then the bonding performance of the tested riveted joint is determined to be insufficient adhesive performance and insufficient adhesive layer bonding surface strength.

4. The method for predicting the performance of a glue-riveted joint according to claim 1, wherein: The method further comprises: performing a tensile test on the rivet joint to be tested to obtain a double-hump tensile curve of the rivet joint to be tested, wherein the horizontal axis of the double-hump tensile curve is the tensile displacement and the vertical axis is the load of the rivet joint to be tested when being stretched; Determining a peak slope of adhesive failure of the adhesive-riveted joint to be tested based on the adhesive failure tensile displacement and the adhesive failure load; The adhesive stiffness of the adhesive-riveted joint to be tested is determined based on the adhesive failure peak slope, and the adhesive stiffness is positively correlated with the adhesive failure peak slope.

5. The method for predicting the performance of adhesive riveted joints according to claim 1, wherein: The riveting performance of the tested adhesive riveted joint is predicted based on the coordinate value of the second hump 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 riveted joint begins to fail, and the ordinate is the riveting failure load when the tested adhesive riveted joint begins to fail; The riveting performance of the tested adhesive riveted joint is positively correlated with the riveting failure tensile displacement and the riveting failure load, including: Determine the rivet failure tensile displacement and the rivet failure load when the tested adhesive riveted joint begins to fail based on the abscissa and ordinate of the second hump coordinate value of the double-hump tensile curve; If the rivet failure tensile displacement is not less than the preset minimum rivet failure displacement, and the rivet failure load is not less than the minimum rivet failure load, it is determined that the riveting performance of the tested adhesive riveted joint meets the preset riveting performance requirements; If the rivet failure tensile displacement is less than the preset minimum rivet failure displacement, and / or the rivet failure load is less than the minimum rivet failure load, it is determined that the riveting performance of the tested adhesive riveted joint does not meet the preset riveting performance requirements.

6. The method for predicting the performance of a glue-riveted joint according to claim 5, wherein: If the rivet failure tensile displacement is less than the preset minimum rivet failure displacement, and / or the rivet failure load is less than the minimum rivet failure load, then determining that the riveting performance of the tested adhesive-riveted joint does not meet the preset riveting performance requirements includes: If the rivet failure tensile displacement is less than the minimum rivet failure displacement, but the rivet failure load is not less than the minimum rivet failure load, it is determined that the riveting performance of the tested adhesive riveted joint is insufficient for the rivet or the connected material. If the rivet failure tensile displacement is not less than the minimum rivet failure displacement, but the rivet failure load is less than the minimum rivet failure load, it is determined that the riveting performance of the tested adhesive riveted joint is insufficient rivet compression; If the rivet failure tensile displacement is less than the minimum rivet failure displacement, and the rivet failure load is less than the minimum rivet failure load, it is determined that the riveting performance of the tested adhesive riveted joint is insufficient in performance of the rivet or the connected material and insufficient in compression of the rivet.

7. The method for predicting the performance of adhesive riveted joints according to claim 1, wherein: The method further comprises: performing a tensile test on the rivet joint to be tested to obtain a double-hump tensile curve of the rivet joint to be tested, wherein the horizontal axis of the double-hump tensile curve is the tensile displacement and the vertical axis is the load of the rivet joint to be tested when being stretched; The product of the bonding failure load and the first strength ratio is set as the bonding ratio upper limit; the first strength ratio is a real number greater than 1 and less than 2; The product of the bonding failure load and the second strength ratio is set as the lower limit of the bonding ratio; the second strength ratio is a real number greater than 0 and less than 1; If the rivet failure load is less than the lower limit of the adhesive bonding ratio, it is determined that the adhesive bonding load of the adhesive-riveted joint to be tested is mainly carried by the adhesive bonding; If the rivet failure load is not less than the lower limit of the bonding ratio and not greater than the upper limit of the bonding ratio, it is determined that the tested glue-riveted joint is loaded by both bonding and riveting; If the rivet failure load is greater than the upper limit of the bonding ratio, it is determined that the tested glue-riveted joint is mainly loaded by riveting.

8. The method for predicting the performance of a glue-riveted joint according to claim 1, wherein: The method further comprises: performing a tensile test on the rivet joint to be tested to obtain a double-hump tensile curve of the rivet joint to be tested, wherein the horizontal axis of the double-hump tensile curve is the tensile displacement and the vertical axis is the load of the rivet joint to be tested when being stretched; Determining the adhesive complete failure displacement of the adhesive riveted joint to be tested based on the double-hump tensile curve, wherein the adhesive 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 a first difference value obtained by subtracting the adhesive joint failure tensile displacement from the adhesive joint complete failure displacement; If the first difference is 0, it is determined that the transition stability from adhesive failure to rivet load of the adhesive-riveted joint to be tested is an overstable transition from adhesive failure to rivet load; If the first difference is greater than 0 and not greater than a preset maximum first difference, it is determined that the transition stability from adhesive failure to rivet load of the adhesive-riveted joint to be tested is a transition from adhesive failure to rivet load stability; If the first difference is greater than the preset maximum first difference, it is determined that the transition stability from adhesive failure to rivet load of the adhesive-riveted joint to be tested is unstable; Among them, the performance of the transition from adhesive failure to super-stable rivet load is better than the performance of the transition from adhesive failure to stable rivet load, and the performance of the transition from adhesive failure to stable rivet load is better than the performance of the transition from adhesive failure to unstable rivet load.

9. The method for predicting the performance of a glue-riveted joint according to claim 8, wherein: The method further comprises: predicting the riveting performance of the tested adhesive riveted joint based on the coordinate value of the second hump 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 riveted joint begins to fail, and the ordinate is the riveting failure load of the tested adhesive riveted joint. Determine the complete adhesive failure load of the adhesive riveted joint to be tested based on the double-hump tensile curve, where the complete adhesive failure load is the vertical coordinate corresponding to the complete adhesive failure displacement; Determining a riveting failure peak slope of the adhesive-riveted joint to be tested based on a difference between the riveting failure tensile displacement and the adhesive complete failure displacement, and a difference between the riveting failure load and the adhesive complete failure load; The riveting stiffness of the tested adhesive-riveted joint is determined based on the riveting failure peak slope, and the riveting stiffness is positively correlated with the riveting failure peak slope.

10. The method for predicting the performance of a glue-riveted joint according to claim 1, wherein: The method further comprises: performing a tensile test on the rivet joint to be tested to obtain a double-hump tensile curve of the rivet joint to be tested, wherein the horizontal axis of the double-hump tensile curve is the tensile displacement and the vertical axis is the load of the rivet joint to be tested when being stretched; Determining the complete rivet failure displacement of the tested adhesive riveted joint based on the double-hump tensile curve, wherein the complete rivet failure displacement is the abscissa corresponding to the minimum value from the second hump coordinate value of the double-hump tensile curve in the positive direction; Calculate a second difference value obtained by subtracting the rivet failure tensile displacement from the rivet complete failure displacement; 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-riveted joint meets the preset riveting failure performance requirement; If the second difference is greater than the preset maximum second difference, it is determined that the riveting failure performance of the tested adhesive riveted joint does not meet the preset riveting failure performance requirements, and the compressive resistance of the connected materials is insufficient.

11. The method for predicting the performance of a glue-riveted joint according to any one of claims 1 to 10, wherein: The riveting performance of the tested adhesive riveted joint is predicted based on the coordinate value of the second hump 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 riveted joint begins to fail, and the ordinate is the riveting failure load when the tested adhesive riveted joint begins to fail; After the riveting performance of the tested adhesive riveted joint is positively correlated with the riveting failure tensile displacement and the riveting failure load, the method further includes: Determining a material failure load ratio based on the connected materials corresponding to the adhesive riveted joint to be tested; the material failure load ratio is a real number greater than 0 and less than 1; setting a product obtained by multiplying the riveting failure load by the material failure load ratio as a first product; On the right side of the second hump coordinate value of the double-hump tensile curve, the abscissa corresponding to the product of the second hump coordinate value and the first hump coordinate value is set as the material failure displacement threshold value; If a third difference between the material failure displacement threshold value and the rivet failure tensile displacement is not greater than a preset displacement threshold value, it is determined that the performance of the connected material corresponding to the tested adhesive riveted joint meets the preset requirements; If the third difference between the material failure displacement threshold value and the rivet failure tensile displacement is greater than the preset displacement threshold value, it is determined that the performance of the connected material corresponding to the tested rivet joint does not meet the preset requirements, and the compression loss resistance of the connected material is insufficient.

12. A device for predicting the performance of a riveted joint, characterized in that: include: memory for storing computer programs; A processor, configured to implement the steps of the method for predicting the performance of a glue-riveted joint as claimed in any one of claims 1 to 11 when executing a computer program.

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