CN108732035B - High-temperature fretting fatigue life testing method for tenon connection structure - Google Patents
High-temperature fretting fatigue life testing method for tenon connection structure Download PDFInfo
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Abstract
The invention discloses a high-temperature fretting fatigue life test method of a tenon connection structure, which comprises the steps of firstly determining the strain or displacement of crack initiation and installing test equipment; then starting a medium temperature fretting fatigue test; determining a judgment standard of displacement mutation during crack initiation; and finally, performing a high-temperature fretting fatigue test and determining the high-temperature fretting fatigue life of the tenon connection structure. The method not only successfully completes the fretting fatigue test of the tenon joint structure at high temperature, but also has low test cost and can simply and accurately obtain the crack initiation life data of the tenon joint structure, so the method has high operability, wide application range and high prediction precision and has considerable engineering application prospect. The invention also discloses a test piece clamp for testing the high-temperature fretting fatigue life of the tenon connecting structure, which comprises an upper clamp with a water cooling device, a lower clamp and a fixing assembly.
Description
Technical Field
The invention relates to the field of fatigue life testing, in particular to a high-temperature fretting fatigue life testing method for a tenon connection structure.
Background
Fretting fatigue is a phenomenon in which when two members are brought into contact under cyclic load, a minute relative sliding occurs between the two contact bodies and the fatigue life of the members is reduced. It has been found that the fatigue strength of the parts can be reduced to 2/3 or less, which is the value of the conventional fatigue strength, under the condition of micro-motion.
Fretting fatigue failure commonly occurs in engineering applications, especially in automotive, rail, energy, and aerospace fields. In the field of aviation, common locations for fretting damage include lap joints of aircraft structures, dovetail connections of turbofan engines. Existing research has shown that high temperature fretting fatigue failure is the primary form of structural failure of tenons and mortises on aircraft engine blades due to their long term operation in high temperature environments.
The clamp for the tenon structure fretting fatigue test is generally a switching Y-shaped clamp, the clamped part of the clamp is cylindrical, and a special clamp for a test piece is required to clamp the clamp, so that the stress direction of the test piece is ensured to be coaxial with the center of an actuator cylinder of a testing machine. However, in the high-temperature fretting fatigue test, the test piece is kept at the maximum temperature of 500 ℃ for a long time, and a general test fixture can damage the tester due to the temperature rise phenomenon. Therefore, a tester cannot use a general jig to complete the high-temperature fretting fatigue test of the tenon joint structure.
The monitoring method for the fretting fatigue life of the tenon structure generally comprises the steps of sticking a strain gauge at the position where the crack is most likely to be initiated in a fretting area, and monitoring the initiation of the fretting fatigue crack by utilizing dynamic strain. However, in the 500 ℃ high-temperature fretting fatigue test, because the instant-curing glue meeting the temperature condition does not exist and the price of the high-temperature strain gauge is too high, the difficulty of sticking the strain gauge in the fretting wear area and the test cost are increased. Therefore, the service life of the tenon joint structure cannot be monitored by a common method when the tenon joint structure is subjected to a high-temperature fretting fatigue test.
Disclosure of Invention
The invention aims to solve the technical problem of providing a high-temperature fretting fatigue life test method of a tenon connection structure aiming at the defects involved in the background technology, which can effectively complete a high-temperature fretting fatigue test and obtain the crack initiation life of a tenon and mortise structure.
The invention adopts the following technical scheme for solving the technical problems:
a high-temperature fretting fatigue life test method for a tenon connection structure comprises a tenon and a wheel disc, wherein a mortise matched with the tenon is arranged on the wheel disc; the head of the tenon is arranged in the mortise and matched with the mortise, and a micro-motion contact area is formed at the contact position of the wall surfaces of the tenon; the tail part of the tenon is fixedly connected with a connecting piece for fixing the tenon;
the high-temperature fretting fatigue life testing method comprises the following steps:
step 1), placing a brand new tenon connection structure in a measurement environment, wherein the specific steps of setting the measurement environment of the tenon connection structure are as follows:
step 1.1), uniformly sticking four medium-temperature strain gauges on the contact side wall of the tenon/mortise, and connecting the four medium-temperature strain gauges into a strain gauge;
step 1.2), an upper clamp and a lower clamp are arranged, and an upper chuck of a fatigue testing machine fixes the connecting piece through the upper clamp and a lower chuck fixes the wheel disc through the lower clamp; the upper clamp and the lower clamp are both made of high-temperature-resistant metal with rigidity larger than a preset rigidity threshold value, and the upper clamp is provided with a cooling device for cooling the temperature transmitted to an upper chuck of the fatigue testing machine by the connecting piece;
step 1.3), respectively arranging three thermocouples on a contact side wall, a connecting piece and a wheel disc of the tenon/mortise, arranging the tenon, the wheel disc and the connecting piece in a high-temperature furnace, and arranging a temperature controller, wherein the temperature controller is respectively electrically connected with the three thermocouples and the high-temperature furnace and is used for controlling the high-temperature furnace to work so that the temperature in the high-temperature furnace is the same as the average temperature of the temperatures induced by the three thermocouples;
step 2), heating the temperature in the high-temperature furnace to a medium temperature through a temperature controller, and then carrying out heat preservation treatment, wherein the medium temperature is 100-250 ℃;
step 3), controlling the fatigue testing machine to perform fatigue stretching on the tenon connection structure by adopting a preset circulating tension frequency and a preset circulating tension amplitude, and recording the change speed of the displacement amplitude of the tenon connection structure at the moment, namely the change speed of the initial displacement amplitude of the current tenon connection structure; detecting the strain peak values of the four medium-temperature strain gauges by a check strain gauge, when the strain peak value of any one of the four medium-temperature strain gauges changes suddenly, considering that fretting fatigue cracks of the tenon connection structure occur, and recording the change speed of the displacement amplitude of the tenon connection structure at the moment, namely the change speed of the sudden change displacement amplitude of the current tenon connection structure;
step 4), dividing the change speed of the sudden change displacement amplitude of the current tenon connection structure by the change speed of the initial displacement amplitude of the current tenon connection structure to obtain a sudden change proportion value;
and 5), controlling the temperature in the high-temperature furnace to increase from a preset first temperature threshold to a preset second temperature threshold according to a preset temperature step by using a temperature controller, wherein for each temperature:
step 5.1), controlling the fatigue testing machine to carry out fatigue stretching on the tenon connection structure, wherein the tensile force of the fatigue testing machine is increased to a preset second tensile force amplitude from a preset first tensile force amplitude according to a preset tensile force step length, and for each tensile force amplitude:
step 5.1.1), placing a brand-new tenon connecting structure in a measuring environment;
step 5.1.2), recording the change speed of the displacement amplitude of the tenon connection structure when the fatigue testing machine starts to stretch the tenon connection structure, namely the change speed of the initial displacement amplitude of the current tenon connection structure;
step 5.1.3), multiplying the initial displacement amplitude change speed of the current tenon connection structure by the mutation proportion value to obtain the predicted mutation displacement amplitude change speed of the current tenon connection structure;
step 5.1.4), testing the current tenon connection structure displacement amplitude change speed through a fatigue testing machine, controlling the fatigue testing machine to stop working when the current tenon connection structure displacement amplitude change speed is equal to the predicted sudden change displacement amplitude change speed of the current tenon connection structure, taking the working time of the fatigue testing machine as the working life of the current tenon connection structure, and recording the current temperature in the high-temperature furnace, the magnitude of the tension amplitude adopted by the current fatigue testing machine and the working life of the current tenon connection structure;
and 6), obtaining the corresponding working life of the tenon connection structure at different temperatures and different tension amplitude values.
As a further optimization scheme of the high-temperature fretting fatigue life testing method for the tenon connection structure, the heat preservation treatment in the step 2) is to keep the middle temperature in a high-temperature furnace for 30-40 minutes.
As a further optimization scheme of the high-temperature fretting fatigue life testing method of the tenon connecting structure, the upper clamp comprises a first clamping part and a cooling device;
the cooling device comprises a first handle and two cooling joints;
the first handle is cylindrical, a cavity is formed in the first handle, and two through holes communicated with the cavity are formed in the wall surface of the first handle;
the two cooling joints are respectively and correspondingly connected with the two through holes on the first handle and are respectively used for inputting and outputting cooling media;
the lower clamp comprises a second clamping part and a second handle;
the first clamping part and the second clamping part respectively comprise a U-shaped clamping plate, a fixing bolt, a fixing nut and a fixing gasket, wherein through holes for the fixing bolt to pass through are formed in two side plates of the U-shaped clamping plate, and the fixing gasket and the fixing nut are matched with the fixing bolt;
one end of the first handle is fixedly connected with the bottom plate of the first clamping part U-shaped clamping plate, and the other end of the first handle is fixed in an upper chuck of the fatigue testing machine;
one end of the second handle is fixedly connected with the bottom plate of the U-shaped clamping plate of the second clamping part, and the other end of the second handle is fixed in a lower chuck of the fatigue testing machine;
the wheel disc is provided with a through hole for the fixing bolt of the second clamping part to pass through, and the fixing bolt in the second clamping part sequentially passes through the corresponding fixing gasket, the through hole on one side plate of the U-shaped clamping plate of the second clamping part, the through hole on the wheel disc, the through hole on the other side plate of the U-shaped clamping plate of the second clamping part and the corresponding fixing nut to be in threaded connection;
the connecting piece is provided with a through hole for the fixing bolt of the first clamping part to pass through; the fixing bolt in the first clamping part sequentially penetrates through the corresponding fixing gasket, the through hole in one side plate of the first clamping part U-shaped clamping plate, the through hole in the connecting piece, the through hole in the other side plate of the first clamping part U-shaped clamping plate and the corresponding fixing nut to be in threaded connection.
As a further optimization scheme of the high-temperature fretting fatigue life testing method of the tenon connecting structure, the upper clamp and the lower clamp are both made of GH4169 alloy.
As a further optimization scheme of the high-temperature fretting fatigue life testing method of the tenon connecting structure, the cooling joint positioned above the first handle is used for flowing in the cooling medium, and the cooling joint positioned below the first handle is used for flowing out the cooling medium.
Compared with the prior art, the invention adopting the technical scheme has the following technical effects:
(1) the invention can carry out the jogging fatigue test of the tenon connection structure with different temperatures under the matching of the uniaxial tension-compression fatigue testing machine, thereby having wide application range.
(2) The judgment standard of the displacement mutation is determined by monitoring the mutation of the dynamic strain in the medium-temperature environment to be a dynamic displacement method, namely the dynamic displacement method is adopted to determine the fretting fatigue crack initiation life of the dovetail structure at high temperature, and the method is simple and easy to implement, low in cost and good in economical efficiency.
(3) Through the whole-process recording of the displacement sensor, the invention can monitor the displacement change curve in the whole high-temperature fretting fatigue test process from the beginning to the end, can capture the initiation of fretting fatigue cracks of the tenon connection structure in time, and provides guarantee for more accurately predicting the high-temperature fretting fatigue life.
Drawings
FIG. 1 is a flow chart of a method for monitoring high temperature fretting fatigue crack initiation life;
FIG. 2 is a schematic structural view of an upper clamp;
FIG. 3 is a schematic view of the construction of the lower clamp;
FIG. 4 is a schematic view of a tongue and groove connection;
FIG. 5 is a schematic view of a bolt, nut and washer;
FIG. 6 is a graph of 200 ℃ dynamic strain and dynamic displacement;
FIG. 7 is a 500 ℃ dynamic displacement curve.
Wherein: 1 is an upper clamp; 11 is a cooling joint; 12 is a cavity; 13 is a first handle; 14 is a through hole on the side plate of the U-shaped clamping plate of the first clamping part; 15 is a first clamping part U-shaped clamping plate; 2, a lower clamp; 21 is a through hole on the side plate of the U-shaped clamping plate of the second clamping part; 22 is a U-shaped splint with a second clamping part; 23 is a second handle; 3 is a connecting piece; 4 is a wheel disc; 5 is the contact side wall of the tenon/mortise; 6 is a fixing nut; 7 is a fixed gasket; and 8, a fixing bolt.
Detailed Description
The technical scheme of the invention is further explained in detail by combining the attached drawings:
the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, components are exaggerated for clarity.
As shown in fig. 1, a method for testing the high-temperature fretting fatigue life of a tenon joint structure comprises the following specific steps:
step 1): before micro fatigue cracks are not initiated, the strain peak value of the tenon/mortise contact side wall 5 changes relatively stably, the strain peak value of the tenon/mortise contact side wall 5 is increased sharply along with the initiation of the fatigue cracks, when the cracks are expanded to a strain grid of a strain gauge, the strain peak value of the tenon/mortise contact side wall 5 is mutated, a medium-temperature strain gauge fails, the length of the cracks is 0.5mm, and the micro fatigue cracks can be considered to be initiated; according to the displacement judgment method for determining the crack initiation life of the tenon-mortise connecting structure, when a fretting fatigue crack is initiated, the dynamic strain at the crack initiation part is subjected to sudden change, the corresponding dynamic displacement is subjected to sudden change, and the sudden change of the displacement rigidity of the whole test device in the test process is monitored through a dynamic displacement sensor of a fatigue test machine, so that the crack initiation life of a test piece is determined.
Four medium-temperature strain gauges are symmetrically adhered to the tenon/mortise contact side wall 5 respectively, the medium-temperature strain gauges are BAB250 type strain gauges produced by the medium-aviation electrical measuring instrument company Limited and are connected into a strain gauge, the strain gauge is a DH3817F dynamic and static strain testing and analyzing system, the system is used for monitoring the strain mutation of the tenon/mortise contact side wall 5, and the monitoring frequency is 10 Hz.
Step 2): fixing a first handle 13 of an upper clamp 1 connected with a cooling device on an upper chuck of an SDS50 fatigue testing machine, then opening a switch of the cooling device to enable water flow to smoothly circulate in the cooling device, fixing a connecting piece 3 on the upper clamp 1 through a fixing nut 6, a fixing gasket 7 and a fixing bolt 8, wherein the fixing nut 6, the fixing gasket 7 and the fixing bolt 8 are not suitable to be matched and over-tightened, the connecting piece 3 can rotate around the fixing bolt 8 in the circumferential direction, correspondingly and cooperatively connecting a wheel disc 4 with a matched second clamping part U-shaped clamping plate 22 according to the above operation, then arranging the head of a tenon in a mortise to be matched with the mortise, forming a micro-motion contact area at the contact position of the wall surfaces, and at the moment, under the action of gravity, the fixing bolt 8 is respectively contacted with the lower end of a through hole 21 on a side plate of the second clamping part and the upper end of a through hole 14 on a side plate of the first clamping, the center of the tenon connecting structure and the center of the upper/lower clamp are kept on the same straight line, and finally the lower chuck of the SDS50 fatigue testing machine is clamped.
Step 3): the thermocouples and the temperature controller are electrically connected with the high-temperature resistance furnace and the three thermocouples are arranged on the contact side wall 5 of the tenon/mortise, the connecting piece 3 and the wheel disc 4, so that the uniform control of the temperature in the furnace is ensured, at the moment, the high-temperature barrel type resistance furnace is used, the temperature in the furnace is set to be heated to the middle temperature of 200 ℃ through the temperature controller, and finally, the high-temperature barrel type resistance furnace is kept for 30min for the subsequent middle temperature 200 ℃ fretting fatigue test;
step 4): setting fretting fatigue test parameters in a DHDAS dynamic signal acquisition and analysis system of an SDS50 fatigue testing machine, setting the load frequency to be 10Hz, the load ratio to be 0.1 and the fatigue load peak value to be 9KN, starting a medium-temperature fretting fatigue test, stopping the SDS50 fatigue testing machine when the strain of the contact side wall 5 of the tenon/mortise monitored by a DH3817F strain gauge through a medium-temperature strain gauge is suddenly changed, placing the fretting fatigue cycle life corresponding to the moment in a displacement amplitude change curve monitored by a displacement sensor of the testing machine for calculation and determining the sudden change proportion value corresponding to the crack initiation, referring to FIG. 6, the point A1 is the crack initiation life corresponding to the failure of any medium-temperature strain gauge, the cycle number at the moment is 30070 times, placing the fretting fatigue cycle life corresponding to the point A1 in the displacement amplitude change curve for observation, and finding that the displacement amplitude change rate at the moment is 2.2 times of the initial displacement amplitude change rate, in order to conveniently observe and record the change condition of the displacement amplitude change rate between the tenon and the mortise under different temperature working conditions in the later period, the method takes the point A2, namely the change rate of the displacement amplitude is 2 times of the change rate of the initial displacement amplitude as the judgment standard of sudden change of the displacement rigidity, and then the test fixture is unloaded and is cooled for 2 hours.
Step 5): replacing a brand new tenon connection structure, and repeating the process from the step 2 to the step 4, wherein the temperature in a high-temperature resistance furnace is heated to 500 ℃ at high temperature, test parameters are set on an SDS50 fatigue testing machine, the load frequency is 10Hz, the load ratio is 0.1, the fatigue load peak value is 9KN as an example, a high-temperature fretting fatigue test is started, as shown in figure 7, at the later stage of fretting fatigue cycle, the maximum displacement amplitude change rate of a tenon and a mortise is obviously changed, the displacement amplitude change rate is 2 times of the initial displacement amplitude change rate and is used as a judgment basis for crack initiation of the high-temperature tenon connection structure, the two broken lines B and C in the two groups of figures are respectively corresponding, when the displacement reaches the fatigue life corresponding to the broken line in figure 7, the initial crack initiation of the tenon connection structure can be considered to have been initiated, and the corresponding cycle number at the moment is considered to be the high temperature of 500 ℃, and the load frequency is 10, the load ratio is 0.1, and the fatigue load peak value is the service life of the tenon joint structure under 9 KN.
Referring to fig. 2, fig. 3, fig. 4 and fig. 5, the test fixture of the high temperature fretting fatigue life test method of the present invention includes an upper fixture 1 with a cooling device, a lower fixture 2 and a fixing assembly. The upper clamp 1 comprises a cooling joint 11, a cavity 12, a first handle 13, a through hole 14 in a side plate of a first clamping part U-shaped clamping plate and a first clamping part U-shaped clamping plate 15, wherein the cooling joint 12 is in threaded connection with the through hole in the side part of the cavity 12, the first handle 13 is connected with the first clamping part U-shaped clamping plate 15 at the lower part, and the through hole 14 in the side plate of the first clamping part U-shaped clamping plate is arranged at the symmetrical center of the first clamping part U-shaped clamping plate 15 and penetrates through the two U-shaped clamping plates. The lower clamp 2 comprises a through hole 21 on a side plate of a U-shaped clamping plate of the second clamping part, a U-shaped clamping plate 22 of the second clamping part and a second handle 23; the through hole 21 on the side plate of the second clamping part U-shaped clamping plate is arranged at the symmetrical center of the second clamping part U-shaped clamping plate 22 and penetrates through the two U-shaped clamping plates. The second grip portion clevis plate 22 is connected to the second handle 23.
The fixed subassembly includes fixation nut 6, fixing gasket 7 and fixing bolt 8, because the middle round bar part of bolt standard component can't satisfy high temperature fine motion fatigue test's demand in the aspect of cylindrical homogeneity and smoothness all betterly, in order to avoid final influence test result, the bolt needs customization processing, fixing bolt 8 wears to locate between through-hole and connecting piece 3's the through-hole on the curb plate of clamping part U-shaped splint, the through-hole of rim plate 4, for the convenience dismouting, adopts clearance fit between fixing bolt 8 and upper/lower anchor clamps and connecting piece 3, the rim plate 4.
As shown in fig. 2, in order to ensure that the heat transferred to the testing machine by the high-temperature fretting fatigue test is sufficiently taken away in the flowing process of water, the water outlets of the two cooling joints 11 are arranged at the upper part and the water inlets thereof are arranged at the lower part. In order to avoid collision between the water inlet and water outlet connectors and the upper chuck of the testing machine, the circle center plane of the connectors is perpendicular to the upper chuck of the testing machine. Two cooling joint 11 correspond with two through-holes on the first handle 13 respectively and adopt threaded connection, have wrapped up in waterproof sticky tape at the screw gap department and prevent the phenomenon that takes place the infiltration in the test process.
In addition, the material of the upper clamp 1 and the lower clamp 2 is preferably high-temperature alloy, such as GH 4169. The GH4169 high-temperature alloy can be repeatedly used in the test process, is not easy to damage, and is suitable for being used as a test clamp for a high-temperature fretting fatigue test.
As a supplement, the through hole 14 on the side plate of the first clamping part U-shaped clamping plate and the through hole 21 on the side plate of the second clamping part U-shaped clamping plate are processed by adopting a slow wire feeding process, so that the circle centers of the two through holes and the center of the fatigue testing machine actuating cylinder are on the same straight line.
As the supplement, the first handle 13 and the second handle 23 of the two clamps are designed into a cylinder shape and are clamped by a special chuck of the cylinder of the testing machine, so that the tenon and the mortise are always stressed in the vertical direction.
In addition, during the operation of the cooling device, the flow of the water flow collides with the wall surface of the cavity 12, so as to form the test result that the vibration affects the high-temperature fretting fatigue, and in order to reduce the phenomenon, a water pumping pump with the power of less than 15kW is selected.
It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
The above-mentioned embodiments, objects, technical solutions and advantages of the present invention are further described in detail, it should be understood that the above-mentioned embodiments are only illustrative of the present invention and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (5)
1. A high-temperature fretting fatigue life test method for a tenon connection structure comprises a tenon and a wheel disc (4), wherein a mortise matched with the tenon is arranged on the wheel disc; the head of the tenon is arranged in the mortise and matched with the mortise, and a micro-motion contact area is formed at the contact position of the wall surfaces of the tenon; the tail part of the tenon is fixedly connected with a connecting piece (3) for fixing the tenon;
the method for testing the high-temperature fretting fatigue life is characterized by comprising the following steps of:
step 1), placing a brand new tenon connection structure in a measurement environment, wherein the specific steps of setting the measurement environment of the tenon connection structure are as follows:
step 1.1), uniformly sticking four medium-temperature strain gauges on a contact side wall (5) of the tenon/mortise, and connecting the four medium-temperature strain gauges into a strain gauge;
step 1.2), an upper clamp (1) and a lower clamp (2) are arranged, an upper chuck of the fatigue testing machine is fixed to the connecting piece (3) through the upper clamp (1), and a lower chuck is fixed to the wheel disc (4) through the lower clamp (2); the upper clamp and the lower clamp are both made of high-temperature-resistant metal with rigidity larger than a preset rigidity threshold value, and the upper clamp is provided with a cooling device for cooling the temperature transmitted to an upper chuck of the fatigue testing machine by the connecting piece;
step 1.3), respectively arranging three thermocouples on a contact side wall (5), a connecting piece (3) and a wheel disc (4) of the tenon/mortise, placing the tenon, the wheel disc and the connecting piece in a high-temperature furnace, and arranging a temperature controller, wherein the temperature controller is respectively electrically connected with the three thermocouples and the high-temperature furnace and is used for controlling the high-temperature furnace to work so that the temperature in the high-temperature furnace is the same as the average temperature of the temperatures sensed by the three thermocouples;
step 2), heating the temperature in the high-temperature furnace to a medium temperature through a temperature controller, and then carrying out heat preservation treatment, wherein the medium temperature is 100-250 ℃;
step 3), controlling the fatigue testing machine to perform fatigue stretching on the tenon connection structure by adopting a preset circulating tension frequency and a preset circulating tension amplitude, and recording the change speed of the displacement amplitude of the tenon connection structure at the moment, namely the change speed of the initial displacement amplitude of the current tenon connection structure; detecting the strain peak values of the four medium-temperature strain gauges by a check strain gauge, when the strain peak value of any one of the four medium-temperature strain gauges changes suddenly, considering that fretting fatigue cracks of the tenon connection structure occur, and recording the change speed of the displacement amplitude of the tenon connection structure at the moment, namely the change speed of the sudden change displacement amplitude of the current tenon connection structure;
step 4), dividing the change speed of the sudden change displacement amplitude of the current tenon connection structure by the change speed of the initial displacement amplitude of the current tenon connection structure to obtain a sudden change proportion value;
and 5), controlling the temperature in the high-temperature furnace to increase from a preset first temperature threshold to a preset second temperature threshold according to a preset temperature step by using a temperature controller, wherein for each temperature:
step 5.1), controlling the fatigue testing machine to carry out fatigue stretching on the tenon connection structure, wherein the tensile force of the fatigue testing machine is increased to a preset second tensile force amplitude from a preset first tensile force amplitude according to a preset tensile force step length, and for each tensile force amplitude:
step 5.1.1), placing a brand-new tenon connecting structure in a measuring environment;
step 5.1.2), recording the change speed of the displacement amplitude of the tenon connection structure when the fatigue testing machine starts to stretch the tenon connection structure, namely the change speed of the initial displacement amplitude of the current tenon connection structure;
step 5.1.3), multiplying the initial displacement amplitude change speed of the current tenon connection structure by the mutation proportion value to obtain the predicted mutation displacement amplitude change speed of the current tenon connection structure;
step 5.1.4), testing the current tenon connection structure displacement amplitude change speed through a fatigue testing machine, controlling the fatigue testing machine to stop working when the current tenon connection structure displacement amplitude change speed is equal to the predicted sudden change displacement amplitude change speed of the current tenon connection structure, taking the working time of the fatigue testing machine as the working life of the current tenon connection structure, and recording the current temperature in the high-temperature furnace, the magnitude of the tension amplitude adopted by the current fatigue testing machine and the working life of the current tenon connection structure;
and 6), obtaining the corresponding working life of the tenon connection structure at different temperatures and different tension amplitude values.
2. The method for testing the high-temperature fretting fatigue life of a tenon joint structure according to claim 1, wherein the heat preservation treatment in the step 2) is to keep the temperature in a high-temperature furnace for 30-40 minutes.
3. A method for testing the fretting fatigue life at high temperatures of a tenon joint structure according to claim 1, wherein the upper jig (1) comprises a first clamping portion and a cooling means;
the cooling device comprises a first handle (13) and two cooling joints (11);
the first handle (13) is cylindrical, a cavity (12) is formed in the first handle, and two through holes communicated with the cavity are formed in the wall surface of the first handle (13);
the two cooling joints (11) are respectively and correspondingly connected with the two through holes on the first handle (13) and are respectively used for inputting and outputting cooling media;
the lower clamp (2) comprises a second clamping part and a second handle (23);
the first clamping part and the second clamping part respectively comprise a U-shaped clamping plate, a fixing bolt (8), a fixing nut (6) and a fixing gasket (7), wherein through holes for the fixing bolt to pass through are formed in two side plates of the U-shaped clamping plate, and the fixing gasket (7) and the fixing nut (6) are matched with the fixing bolt (8);
one end of the first handle (13) is fixedly connected with a bottom plate of the first clamping part U-shaped clamping plate (15), and the other end of the first handle is fixed in an upper clamping head of the fatigue testing machine;
one end of the second handle (23) is fixedly connected with a bottom plate of the second clamping part U-shaped clamping plate (22), and the other end of the second handle is fixed in a lower clamping head of the fatigue testing machine;
the wheel disc is provided with a through hole for the fixing bolt of the second clamping part to pass through, and the fixing bolt (8) in the second clamping part sequentially passes through the corresponding fixing gasket (7), the through hole (21) on one side plate of the U-shaped clamping plate of the second clamping part, the through hole on the wheel disc, the through hole (21) on the other side plate of the U-shaped clamping plate of the second clamping part and the corresponding fixing nut (6) to be in threaded connection;
the connecting piece is provided with a through hole for the fixing bolt of the first clamping part to pass through; and the fixing bolt (8) in the first clamping part sequentially penetrates through the corresponding fixing gasket (7), the through hole (14) on one side plate of the U-shaped clamping plate of the first clamping part, the through hole on the connecting piece, the through hole (14) on the other side plate of the U-shaped clamping plate of the first clamping part and the corresponding fixing nut (6) to be in threaded connection.
4. The method for testing the high-temperature fretting fatigue life of a tenon joint structure according to claim 1, wherein the upper clamp (1) and the lower clamp (2) are both made of GH4169 alloy.
5. A method for testing the fretting fatigue life at high temperature of a tenon joint structure according to claim 3, wherein the cooling joint (11) located at the upper part of the first handle (13) is used for flowing in the cooling medium, and the cooling joint (11) located at the lower part is used for flowing out the cooling medium.
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| CN113720590A (en) * | 2021-07-30 | 2021-11-30 | 中国航发沈阳发动机研究所 | Fretting fatigue simulation test device and method |
| CN114608979A (en) * | 2022-03-22 | 2022-06-10 | 西南交通大学 | Bending-torsion composite high-temperature fretting fatigue test device |
| CN114813414A (en) * | 2022-05-27 | 2022-07-29 | 南京航空航天大学 | Extreme high temperature normal position tenon joint fretting fatigue experimental apparatus |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105043976A (en) * | 2015-07-28 | 2015-11-11 | 南京航空航天大学 | Test device for dynamically measuring fretting pair frictional coefficient during fretting fatigue process and test method |
| CN105067428A (en) * | 2015-08-13 | 2015-11-18 | 芜湖市汽车产业技术研究院有限公司 | Crack initiation life test machine for elastic materials and using method thereof |
| JP2016180597A (en) * | 2015-03-23 | 2016-10-13 | 三菱重工業株式会社 | Fretting fatigue evaluation method |
| CN106442182A (en) * | 2016-09-20 | 2017-02-22 | 四川大学 | High-temperature micro-motion fatigue experiment clamping and loading device |
| CN207051129U (en) * | 2017-08-11 | 2018-02-27 | 西北工业大学 | Fretting fatigue testing system |
| CN107884290A (en) * | 2017-10-16 | 2018-04-06 | 北京理工大学 | A kind of fretting fatigue cracks extension life-span prediction method under consideration effect of attrition |
-
2018
- 2018-04-28 CN CN201810399004.XA patent/CN108732035B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2016180597A (en) * | 2015-03-23 | 2016-10-13 | 三菱重工業株式会社 | Fretting fatigue evaluation method |
| CN105043976A (en) * | 2015-07-28 | 2015-11-11 | 南京航空航天大学 | Test device for dynamically measuring fretting pair frictional coefficient during fretting fatigue process and test method |
| CN105067428A (en) * | 2015-08-13 | 2015-11-18 | 芜湖市汽车产业技术研究院有限公司 | Crack initiation life test machine for elastic materials and using method thereof |
| CN106442182A (en) * | 2016-09-20 | 2017-02-22 | 四川大学 | High-temperature micro-motion fatigue experiment clamping and loading device |
| CN207051129U (en) * | 2017-08-11 | 2018-02-27 | 西北工业大学 | Fretting fatigue testing system |
| CN107884290A (en) * | 2017-10-16 | 2018-04-06 | 北京理工大学 | A kind of fretting fatigue cracks extension life-span prediction method under consideration effect of attrition |
Non-Patent Citations (2)
| Title |
|---|
| 榫连接结构高温低周微动疲劳试验;王楠 等;《航空动力学报》;20181231;第33卷(第12期);全文 * |
| 高低周载荷作用下燕尾榫结构的微动疲劳寿命预测;古远兴 等;《推进技术》;20080430;第29卷(第2期);全文 * |
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