CN114199446A - Bolt stress testing device and method - Google Patents
Bolt stress testing device and method Download PDFInfo
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- CN114199446A CN114199446A CN202111439642.8A CN202111439642A CN114199446A CN 114199446 A CN114199446 A CN 114199446A CN 202111439642 A CN202111439642 A CN 202111439642A CN 114199446 A CN114199446 A CN 114199446A
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- 238000009662 stress testing Methods 0.000 title claims abstract description 37
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- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
- G01L5/24—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for determining value of torque or twisting moment for tightening a nut or other member which is similarly stressed
- G01L5/246—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for determining value of torque or twisting moment for tightening a nut or other member which is similarly stressed using acoustic waves
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Abstract
The application relates to a bolt stress testing device and method. The device comprises: the strain gauge is arranged in a through hole in the middle of the bolt, and the extending direction of the through hole is consistent with the extending direction of the bolt body; the data acquisition instrument is electrically connected with the strain gauge and is used for acquiring dynamic stress data of the bolt; under the condition that the bolt is balanced, by acquiring dynamic stress data of the bolt under different test working conditions of the vehicle, the service life and/or the stress distribution strength of the bolt are judged according to the dynamic stress data and the known average stress data of the bolt. By adopting the device, the dynamic stress of the bolt in service can be simply and accurately obtained, so that the service life and the stress distribution strength of the bolt can be obtained.
Description
Technical Field
The application relates to the technical field of testing, in particular to a bolt stress testing device and method.
Background
The bolt is a mechanical part used for fastening and connecting two parts with through holes. This form of connection is known as a bolted connection. The bolt connection is the most common connection mode of the existing part connection, and is particularly important for the service life of parts in order to ensure the part connection safety and accurately obtain the stress condition of the bolt in the service period.
The traditional bolt stress testing method mainly comprises three types: the method comprises a bolt stress ultrasonic detection method, a photoelastic stress test method and a resistance strain gauge electrical measurement method. According to the ultrasonic detection bolt stress testing method, the effective length and the stressed area of threaded connection are obtained according to the installation mode of a bolt, and the stress of the bolt is obtained through calculation; the photoelastic stress test method is characterized in that a plane light test is carried out by utilizing a photoelastic meter, polarized light is decomposed into two beams of polarized light along a main stress direction, and an optical path difference is formed after reflection, so that the stress of a bolt is obtained through calculation; the electrical method of the resistance strain gauge needs to cut the bolt into a plane, and the stress of the bolt is calculated through a Wheatstone bridge. However, the method has the problems that the testing process is complex, the cost is high, the reliability is insufficient due to errors caused by measuring the stress of the surface, and the manufacturing period is long.
Disclosure of Invention
In view of the above, it is necessary to provide a bolt stress testing apparatus and method to accurately obtain the dynamic stress of the bolt during service.
In order to achieve the above and other objects, an aspect of the present application provides a bolt stress testing apparatus, the apparatus including:
the strain gauge is arranged in a through hole in the middle of the bolt, and the extending direction of the through hole is consistent with the extending direction of the bolt body;
the data acquisition instrument is electrically connected with the strain gauge and is used for acquiring dynamic stress data of the bolt;
under the condition that the bolt is balanced, by acquiring dynamic stress data of the bolt under different test working conditions of a vehicle, the service life and/or the stress distribution strength of the bolt are judged according to the dynamic stress data and the known average stress data of the bolt.
In the bolt stress testing device in the above embodiment, the embedded strain gauge is arranged in the bolt, so that the strain gauge can be stably fixed in the tested bolt, thereby avoiding the test failure caused by the strain gauge falling and being damaged due to external collision, eliminating the eccentric error caused by the fact that only the strain on the surface of the bolt can be measured when the strain gauge is arranged on the surface, and reducing the bolt stress test error. And acquiring dynamic stress data of the bolt through a data acquisition instrument, and judging the service life and/or stress distribution intensity of the bolt according to the dynamic stress data and the known average stress data of the bolt, thereby obtaining the accurate dynamic stress of the bolt in service. The device has the advantages of simple installation, accurate data and the like.
In one embodiment, the data acquisition instrument comprises:
a Wheatstone bridge configured to: the test port is used for collecting the output voltage of the strain gauge;
and the differential amplification circuit is electrically connected with the output end of the half bridge wall of the Wheatstone bridge and is used for outputting the dynamic stress data. The Wheatstone bridge is used to convert the measured stress (non-electricity) into the change of resistance value, the stress is measured visually by measuring the change of resistance value, and the dynamic stress data collected by the strain gauge is stably amplified by the differential amplifier circuit.
In one embodiment, the data acquisition instrument further comprises:
and the anti-mixing filter circuit is electrically connected with the output end of the differential amplification circuit and is used for filtering and correcting the dynamic stress data and outputting the corrected dynamic stress data. So as to make the dynamic stress data more accurate and stable.
In one embodiment, the bolt stress testing apparatus further includes:
the controller is connected with the output end of the data acquisition instrument and is used for storing the dynamic stress data of the bolt; and/or
And the display is connected with the controller and used for displaying the real-time stress change curve of the bolt according to the dynamic stress data of the bolt. So as to obtain a real-time stress change curve through the controller and the display.
In one embodiment, the controller is configured to:
acquiring bolt parameters and the known average stress data;
acquiring dynamic stress data of a bolt on a vehicle under different test working conditions;
filtering, denoising and/or removing trend terms of the dynamic stress data to obtain a preprocessing signal;
and judging the service life and/or the stress distribution intensity of the bolt according to the bolt parameters, the known average stress data and the preprocessing signal. So as to judge the bolt state through real-time dynamic stress.
In one embodiment, the bolt parameters include the modulus of elasticity and/or poisson's ratio of the bolt. So as to facilitate the initial evaluation of the bolt, roughly confirming the stress range of the test.
Another aspect of the present application provides a bolt stress testing method, which is performed based on the bolt stress testing apparatus described in any embodiment of the present application, and the method includes:
fixing a strain gauge inside the bolt, and electrically connecting the strain gauge with a data acquisition instrument;
pretreating the bolt to obtain a clean bolt with impurities removed, wherein the impurities comprise scrap iron and/or dust;
and placing the cleaning bolt in a vehicle, and under the condition that the cleaning bolt is balanced, judging the service life and/or the stress distribution strength of the bolt according to the dynamic stress data and the known average stress data by acquiring the dynamic stress data of the cleaning bolt under different test working conditions of the vehicle.
In the control method of the dc transformer in the above embodiment, the strain gauge is fixed inside the bolt, so that an eccentric error caused by that only the strain on the surface of the bolt can be measured when the strain gauge is arranged on the surface is avoided. And then the bolt is preprocessed, so that strain errors caused by impurities such as scrap iron, dust and the like are avoided. The cleaning bolt is placed in the vehicle so that it is balanced to avoid strain errors due to vehicle movement displacements. And finally, judging the service life and/or the stress distribution strength of the bolt according to the dynamic stress data and the known average stress data.
In one embodiment, the bolt stress testing method comprises the following steps:
and under the premise that the bolt is tightly connected with the connected piece, acquiring a pre-tightening deformation signal generated by the strain gauge due to the tight connection, and determining the known average stress data according to the pre-tightening deformation signal. Because the bolt can produce the pretightning force when being connected tightly with by the connecting piece and consequently make the foil gage produce deformation, so utilize average stress data to revise dynamic stress data and will obtain more accurate bolt dynamic stress during service.
In one embodiment, the bolt stress testing method comprises the following steps:
acquiring bolt parameters and the known average stress data;
acquiring dynamic stress data of a bolt on a vehicle under different test working conditions;
filtering, denoising and/or removing trend terms of the dynamic stress data to obtain a preprocessing signal;
and judging the service life and/or the stress distribution intensity of the bolt according to the bolt parameters, the known average stress data and the preprocessing signal. So as to obtain the dynamic stress of the bolt during service, thereby obtaining the service life and the stress distribution strength of the bolt.
In one embodiment, the bolt parameters include the modulus of elasticity and/or poisson's ratio of the bolt. So as to facilitate the initial evaluation of the bolt, roughly confirming the stress range of the test.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a bolt stress testing apparatus provided in an embodiment of the present application;
fig. 2 is a schematic structural diagram of a tested bolt provided in an embodiment of the present application;
fig. 3 is a schematic wiring diagram of a bolt stress testing apparatus provided in an embodiment of the present application;
fig. 4 is a schematic structural diagram of a wheatstone bridge in a bolt stress testing apparatus according to an embodiment of the present application;
fig. 5 is a schematic diagram illustrating a real-time stress variation curve of a display in the bolt stress testing apparatus according to an embodiment of the present disclosure;
FIG. 6 is a schematic flow chart illustrating a method for testing stress of a bolt according to an embodiment of the present disclosure;
FIG. 7 is a schematic flow chart illustrating a method for testing stress of a bolt according to another embodiment of the present disclosure;
fig. 8 is a schematic flowchart of a bolt stress testing method provided in another embodiment of the present application.
Description of reference numerals:
1. a bolt; 2. a strain gauge; 3. a through hole; 4. a data acquisition instrument.
Detailed Description
To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Embodiments of the present application are set forth in the accompanying drawings. This application may, however, 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.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.
It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or be connected to the other element through intervening elements. Further, "connection" in the following embodiments is understood to mean "electrical connection", "communication connection", or the like, if there is a transfer of electrical signals or data between the connected objects.
As used herein, the singular forms "a", "an" and "the" may include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises/comprising," "includes" or "including," etc., specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof. Also, as used in this specification, the term "and/or" includes any and all combinations of the associated listed items.
In the traditional method for testing the stress of the bolt, for a published patent, for example, CN209745449U discloses an ultrasonic bolt axial testing device, which utilizes wavelength difference to calculate the stress of the bolt, but the method has higher manufacturing cost and complex process, and is not suitable for engineering practice; CN211855645U discloses a device for testing arc-shaped bolt stress through a fiber grating sensor, but the method has limited application scenes and cannot obtain a dynamic stress load spectrum of a bolt in service; CN112729622A calculates corresponding bolt stress through electromagnetic induction coil and the reverse residual magnetization of bolt, and the operation is complicated, and the magnetic field can lead to stress calculation to have the deviation in whole car, therefore is not suitable for whole car scene.
Based on this, please refer to fig. 1, in an embodiment of the present application, a bolt stress testing apparatus is provided, the apparatus includes a stress sheet 2 and a data acquisition instrument 4, the stress sheet 2 is disposed in a through hole 3 in a middle portion of the bolt 1, and an extending direction of the through hole 3 is consistent with an extending direction of a body of the bolt 1; the data acquisition instrument 4 is electrically connected with the strain gauge 2 and is used for acquiring dynamic stress data of the bolt 1;
under the condition that the bolt is balanced, by acquiring dynamic stress data of the bolt under different test working conditions of a vehicle, the service life and/or the stress distribution strength of the bolt are judged according to the dynamic stress data and the known average stress data of the bolt.
Specifically, according to the type of the tested bolt, a through hole 3 is processed in the center of the tested bolt, as shown in fig. 2. For example, the diameter of the through-hole 3 may be φ 2, and then the strain gauge 2 may be fixed in the through-hole 3 using a special adhesive. The connection mode of the device is as shown in fig. 3, the strain gauge is connected with a connecting wire, the connecting wire is a 7-pin wire harness, and the connecting wire is divided into red according to different colors: a power supply is positive; black: the power supply is negative; green: the signal is positive; white: the signal is negative; yellow: 1/4 a bridge; blue color: a signal stabilizing line and an outer layer; purple: the power shielding wire is connected with the power supply and one end of the strain gauge, the signal and the 1/4 bridge are connected with the signal stabilizing wire and the other end of the strain gauge, the connecting wire plays a role in data transmission, and the dynamic stress condition of the bolt is recorded through the data acquisition instrument.
In the bolt stress testing device in the above embodiment, the embedded strain gauge is arranged in the bolt, so that the strain gauge can be stably fixed in the tested bolt, thereby avoiding the test failure caused by the strain gauge falling and being damaged due to external collision, eliminating the eccentric error caused by the fact that only the strain on the surface of the bolt can be measured when the strain gauge is arranged on the surface, and reducing the bolt stress test error. And acquiring dynamic stress data of the bolt through a data acquisition instrument, and judging the service life and/or stress distribution intensity of the bolt according to the dynamic stress data and the known average stress data of the bolt, thereby obtaining the accurate dynamic stress of the bolt in service. The device has the advantages of simple installation, accurate data and the like.
In one embodiment, the data acquisition instrument includes a wheatstone bridge and a differential amplification circuit, the wheatstone bridge configured to: the test port is used for collecting the output voltage of the strain gauge; and the differential amplification circuit is electrically connected with the output end of the half bridge wall of the Wheatstone bridge and is used for outputting the dynamic stress data. The Wheatstone bridge is used to convert the measured stress (non-electricity) into the change of resistance value, the stress is measured visually by measuring the change of resistance value, and the dynamic stress data collected by the strain gauge is stably amplified by the differential amplifier circuit.
Specifically, the resistance value change in stress measurement is usually small, and a wheatstone bridge is usually introduced to measure a small change in resistance, and the wheatstone bridge is formed by combining four resistors. For example, an 1/4 bridge stress measurement can be used, as shown in fig. 4, R1 is connected to the strain gauge, and when the strain gauge changes, assuming that the resistance change amount is Δ R, the calculation formula of the output voltage e is as follows:
e is the output voltage of the bridge, Δ R is the resistance change due to strain gauge deformation, R is the resistance of R1, E is the input voltage of the bridge, k is the proportionality constant, and ε is the strain. Except for epsilon, the above equation is a known quantity, so the magnitude of the strain can be calculated if the output voltage of the bridge is measured.
In one embodiment, the data acquisition instrument further includes an anti-aliasing filter circuit, and the anti-aliasing filter circuit is electrically connected to the output end of the differential amplification circuit, and is configured to perform filtering correction on the dynamic stress data and output the corrected dynamic stress data. So as to make the dynamic stress data more accurate and stable.
In one embodiment, the bolt stress testing device further comprises a controller and a display, wherein the controller is connected with the output end of the data acquisition instrument and used for storing dynamic stress data of the bolt; and/or the display is connected with the controller and used for displaying the real-time stress change curve of the bolt according to the dynamic stress data of the bolt. So as to obtain a real-time stress variation curve through the controller and the display, as shown in fig. 5, which is a real-time stress variation curve graph that may appear in the embodiment of the present application.
In one embodiment, the controller is configured to:
acquiring bolt parameters and the known average stress data;
acquiring dynamic stress data of a bolt on a vehicle under different test working conditions;
filtering, denoising and/or removing trend terms of the dynamic stress data to obtain a preprocessing signal;
and judging the service life and/or the stress distribution intensity of the bolt according to the bolt parameters, the known average stress data and the preprocessing signal. So as to judge the bolt state through real-time dynamic stress.
Specifically, firstly, the tested bolt is placed vertically on a horizontal plane, the bolt is in a free state, then according to the wiring method shown in fig. 3, secondly, the connecting wire is connected with a strain gauge in the tested bolt, a heat shrink tube is utilized for sealing, short circuit during testing is avoided, meanwhile, the connecting wire is connected with a data acquisition instrument, parameters are set for the data acquisition instrument, when stress strain testing is carried out, a bridge circuit mode is required to be selected to be 1/4 bridge, only one active strain gauge is arranged, the strain gauge is under uniaxial tension and compression, the resistance of the strain gauge is 120 Ω, the sensitivity coefficient of the strain gauge is 2.07, meanwhile, the elastic modulus and poisson ratio of the tested bolt are input, the sampling frequency is set to be 500Hz, and the stress initial stage of the connected piece is evaluated, and the stress range of the test is confirmed.
Secondly, carrying out balance setting by using a data acquisition instrument, initializing a detection device, simultaneously carrying out peeling balance, recording compensation amount displayed by a software interface, namely fixing deformation generated on the strain gauge, if the balance state is not executed in the configuration interface of the data recorder, indicating that a short circuit exists in the connection of a circuit or the strain gauge of the test device, then fastening the tested bolt to a connected piece, carrying out balance setting again, and recording deformation generated by pretightening force generated when the tested bolt is pretightened on the strain gauge, wherein the deformation is the average stress of the strain gauge in the service period. And then the tested bolt is placed in a vehicle, and the data acquisition instrument is placed in a stable zone in a vehicle cab, so that irreparable damage to the data acquisition instrument due to bumping in the test process is avoided.
Before the test is started, the vehicle is flamed out and is static, the hand brake is loosened, no operation is carried out on the vehicle, unnecessary load caused by other vibration is avoided, then the tested bolt is initialized and balanced again, then the test starting button is clicked, the test curve is observed, whether the starting point is 0 or not is confirmed, if the starting point is 0, starting the vehicle for testing, if the starting point is not 0, repeating the balancing operation until the starting point fluctuates around 0, after the test is started, the dynamic stress of the bolt during service is recorded through a data acquisition instrument and data software, the tested vehicle is driven according to a preset test working condition, a difference circuit, an anti-aliasing filter and the like are utilized to correct a test result, and in order to avoid the condition that the test data deviates from a true value due to factors such as the operation influence of a driver, the random excitation of a road surface and the like, the vehicle is required to be driven to at least complete three cycles of a comprehensive driving working condition.
And finally, analyzing the acquired dynamic stress data, firstly preprocessing the dynamic stress data, removing irrelevant information from the dynamic stress data, including but not limited to operations such as filtering, denoising, trend item removal and the like, so as to obtain clean and impurity-free preprocessed data, deforming a strain gage generated by pretightening force, wherein the deformation is the average stress of the bolt in service, correcting by utilizing the average stress, selecting a proper average stress correction method, converting the preprocessed data obtained by testing, so as to obtain the dynamic stress of the bolt in service, and further calculating the service life and the stress distribution strength of the bolt.
In one embodiment, the bolt parameters include the modulus of elasticity and/or poisson's ratio of the bolt. So as to facilitate the initial evaluation of the bolt, roughly confirming the stress range of the test.
In an embodiment of the present application, please refer to fig. 6, which provides a bolt stress testing method, executed based on the bolt stress testing apparatus in any embodiment of the present application, the method includes the following steps:
step S11: and fixing the strain gauge inside the bolt, and electrically connecting the strain gauge with a data acquisition instrument.
Specifically, firstly, according to the type of a tested bolt, a through hole is processed in the center of the tested bolt, then the strain gauge is fixed in the through hole by using a special adhesive, then the tested bolt is placed on a horizontal plane and is vertically placed, so that the bolt is in a free state, finally, according to the wiring method shown in fig. 3, a connecting wire is well connected with the strain gauge in the tested bolt, a heat-shrinkable tube is utilized for sealing, short circuit during testing is avoided, and meanwhile, the connecting wire is connected with a data acquisition instrument.
Step S12: and (3) preprocessing the bolt to obtain the clean bolt with impurities removed, wherein the impurities comprise scrap iron and/or dust.
In particular, the through hole can be cleaned by alcohol, cotton swab and related tools, strain error caused by impurities such as scrap iron, dust and the like is avoided,
step S13: and placing the cleaning bolt in a vehicle, and under the condition that the cleaning bolt is balanced, judging the service life and/or the stress distribution strength of the bolt according to the dynamic stress data and the known average stress data by acquiring the dynamic stress data of the cleaning bolt under different test working conditions of the vehicle.
Specifically, the cleaning bolt is placed in a vehicle, and the data acquisition instrument is placed in a stable zone in a cab of the vehicle, so that irreparable damage to the data acquisition instrument due to jolt in a test process is avoided. Before the test is started, the vehicle is flamed out and is static, a hand brake is loosened, no operation is performed on the vehicle, unnecessary load caused by other vibration is avoided, initialization and balance operation is performed on the cleaning bolt, then a test starting button is clicked, a test curve is observed, whether the initial point is 0 or not is confirmed, if the initial point is 0, the vehicle is started to perform the test, if the initial point is not 0, balance operation is repeatedly performed until the initial point fluctuates near 0, after the test is started, the dynamic stress of the bolt in service is recorded through a data acquisition instrument and data software, the tested vehicle is driven according to a preset test working condition, the test result is corrected, in order to avoid that the test data deviates from a true value due to factors such as operation influence of a driver and random excitation of a road surface, the vehicle is required to be driven, and at least three cycles of a comprehensive driving working condition are completed. And finally, analyzing the collected dynamic stress data, correcting by using the average stress, selecting a proper average stress correction method, and converting the dynamic stress data obtained by testing to obtain the dynamic stress of the bolt in service so as to obtain the service life and the stress distribution strength of the bolt.
In the control method of the dc transformer in the above embodiment, the strain gauge is fixed inside the bolt, so that an eccentric error caused by that only the strain on the surface of the bolt can be measured when the strain gauge is arranged on the surface is avoided. And then the bolt is preprocessed, so that strain errors caused by impurities such as scrap iron, dust and the like are avoided. The cleaning bolt is placed in the vehicle so that it is balanced to avoid strain errors due to vehicle movement displacements. And finally, judging the service life and/or the stress distribution strength of the bolt according to the dynamic stress data and the known average stress data.
Referring to fig. 7, in one embodiment, the bolt stress testing method includes the following steps:
step S20: and under the premise that the bolt is tightly connected with the connected piece, acquiring a pre-tightening deformation signal generated by the strain gauge due to the tight connection, and determining the known average stress data according to the pre-tightening deformation signal. Because the bolt can produce the pretightning force when being connected tightly with by the connecting piece and consequently make the foil gage produce deformation, so utilize average stress data to revise dynamic stress data and will obtain more accurate bolt dynamic stress during service.
Specifically, firstly, a data acquisition instrument is used for carrying out balance setting, a detection device is initialized, meanwhile, peeling balance is carried out, compensation quantity displayed on a software interface is recorded, the compensation quantity is deformation generated by fixing the strain gauge, if a balance state is displayed on a configuration interface of the data acquisition instrument and is not executed, the situation that a short circuit exists in the connection of a circuit or the strain gauge of the test device is indicated, then a tested bolt is fastened to a connected piece, and the balance setting is carried out again, and deformation generated by pre-tightening force generated when the tested bolt is pre-tightened is recorded, and the deformation is average stress data of the strain gauge in the service period.
Referring to fig. 8, in one embodiment, the bolt stress testing method includes the following steps:
step S31: acquiring bolt parameters and the known average stress data;
step S32: acquiring dynamic stress data of a bolt on a vehicle under different test working conditions;
step S33: filtering, denoising and/or removing trend terms of the dynamic stress data to obtain a preprocessing signal;
step S34: and judging the service life and/or the stress distribution intensity of the bolt according to the bolt parameters, the known average stress data and the preprocessing signal. So as to obtain the dynamic stress of the bolt during service, thereby obtaining the service life and the stress distribution strength of the bolt.
Specifically, the strain gauge, which is generated by the pretension, deforms, which is the average stress data during the service life of the bolt. After the test is started, the dynamic stress of the bolt in the service period is recorded through the data acquisition instrument and the data software, the tested vehicle is driven according to the preset test working condition, the test result is corrected by utilizing a differential circuit, an anti-aliasing filter and the like, and in order to avoid the condition that the test data deviates from the true value due to the factors such as the operation influence of a driver, the random excitation of the road surface and the like, the vehicle is required to be driven to at least complete three cycles of the comprehensive driving working condition. And finally, analyzing the acquired dynamic stress data, preprocessing the dynamic stress data, removing irrelevant information from the dynamic stress data, including but not limited to operations such as filtering, denoising, trend item removing and the like, so as to obtain a clean and impurity-free preprocessing signal, and judging the service life and/or stress distribution intensity of the bolt according to the bolt parameters, the known average stress data and the preprocessing signal.
In one embodiment, the bolt parameters include the modulus of elasticity and/or poisson's ratio of the bolt. So as to facilitate the initial evaluation of the bolt, roughly confirming the stress range of the test.
Specifically, when a stress-strain test is carried out, a bridge circuit mode needs to be selected as an 1/4 bridge, only one active strain gauge is provided, the strain gauge is under uniaxial tension and compression, the resistance of the strain gauge is 120 Ω, the sensitivity coefficient of the strain gauge is 2.07, meanwhile, the elastic modulus and the Poisson ratio of a tested bolt are input, the sampling frequency is set to be 500Hz, the initial stress evaluation of a connected piece is carried out, and the stress range of the test is confirmed.
It should be understood that although the various steps in the flowcharts of fig. 6-8 are shown in order as indicated by the arrows, the steps are not necessarily performed in order as indicated by the arrows. The steps are not performed in the exact order shown and described, and may be performed in other orders, unless explicitly stated otherwise. Also, at least some of the steps in fig. 6-8 may include multiple steps or multiple stages, which are not necessarily performed at the same time, but may be performed at different times, which are not necessarily performed in sequence, but may be performed in turn or alternately with other steps or at least some of the other steps or stages.
In the description herein, references to the description of "some embodiments," "other embodiments," "desired embodiments," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, a schematic description of the above terminology may not necessarily refer to the same embodiment or example.
The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. A bolt stress testing device is characterized by comprising:
the strain gauge is arranged in a through hole in the middle of the bolt, and the extending direction of the through hole is consistent with the extending direction of the bolt body;
the data acquisition instrument is electrically connected with the strain gauge and is used for acquiring dynamic stress data of the bolt;
under the condition that the bolt is balanced, by acquiring dynamic stress data of the bolt under different test working conditions of a vehicle, the service life and/or the stress distribution strength of the bolt are judged according to the dynamic stress data and the known average stress data of the bolt.
2. The bolt stress testing device of claim 1, wherein the data acquisition instrument comprises:
a Wheatstone bridge configured to: the test port is used for collecting the output voltage of the strain gauge;
and the differential amplification circuit is electrically connected with the output end of the half bridge wall of the Wheatstone bridge and is used for outputting the dynamic stress data.
3. The bolt stress testing device of claim 2, wherein the data acquisition instrument further comprises:
and the anti-mixing filter circuit is electrically connected with the output end of the differential amplification circuit and is used for filtering and correcting the dynamic stress data and outputting the corrected dynamic stress data.
4. The bolt stress testing device of any one of claims 1-3, further comprising:
the controller is connected with the output end of the data acquisition instrument and is used for storing the dynamic stress data of the bolt; and/or
And the display is connected with the controller and used for displaying the real-time stress change curve of the bolt according to the dynamic stress data of the bolt.
5. The bolt stress testing apparatus of claim 4, wherein the controller is configured to:
acquiring bolt parameters and the known average stress data;
acquiring dynamic stress data of a bolt on a vehicle under different test working conditions;
filtering, denoising and/or removing trend terms of the dynamic stress data to obtain a preprocessing signal;
and judging the service life and/or the stress distribution intensity of the bolt according to the bolt parameters, the known average stress data and the preprocessing signal.
6. Bolt stress testing device according to claim 5, wherein the bolt parameters comprise the modulus of elasticity and/or Poisson's ratio of the bolt.
7. A bolt stress testing method, which is performed based on the bolt stress testing apparatus of any one of claims 1 to 6, the method comprising:
fixing a strain gauge inside the bolt, and electrically connecting the strain gauge with a data acquisition instrument;
pretreating the bolt to obtain a clean bolt with impurities removed, wherein the impurities comprise scrap iron and/or dust;
and placing the cleaning bolt in a vehicle, and under the condition that the cleaning bolt is balanced, judging the service life and/or the stress distribution strength of the bolt according to the dynamic stress data and the known average stress data by acquiring the dynamic stress data of the cleaning bolt under different test working conditions of the vehicle.
8. The bolt stress testing method of claim 7, wherein the method comprises:
and under the premise that the bolt is tightly connected with the connected piece, acquiring a pre-tightening deformation signal generated by the strain gauge due to the tight connection, and determining the known average stress data according to the pre-tightening deformation signal.
9. The bolt stress testing method of claim 8, wherein the method comprises:
acquiring bolt parameters and the known average stress data;
acquiring dynamic stress data of a bolt on a vehicle under different test working conditions;
filtering, denoising and/or removing trend terms of the dynamic stress data to obtain a preprocessing signal;
and judging the service life and/or the stress distribution intensity of the bolt according to the bolt parameters, the known average stress data and the preprocessing signal.
10. The bolt stress testing method of claim 9, wherein the bolt parameters comprise a modulus of elasticity and/or a poisson's ratio of the bolt.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111439642.8A CN114199446A (en) | 2021-11-30 | 2021-11-30 | Bolt stress testing device and method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111439642.8A CN114199446A (en) | 2021-11-30 | 2021-11-30 | Bolt stress testing device and method |
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| CN114199446A true CN114199446A (en) | 2022-03-18 |
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| CN105571691A (en) * | 2014-10-09 | 2016-05-11 | 梅特勒-托利多(常州)精密仪器有限公司 | Weighing sensor, weighing network, and monitoring method |
| CN110608839A (en) * | 2019-02-26 | 2019-12-24 | 蚌埠学院 | Wireless bolt pretightening force sensor |
| CN112945435A (en) * | 2021-02-04 | 2021-06-11 | 包头盛泰汽车零部件制造有限公司 | Method for testing axial force of bolt for wheel |
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2021
- 2021-11-30 CN CN202111439642.8A patent/CN114199446A/en active Pending
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| CN105571691A (en) * | 2014-10-09 | 2016-05-11 | 梅特勒-托利多(常州)精密仪器有限公司 | Weighing sensor, weighing network, and monitoring method |
| CN110608839A (en) * | 2019-02-26 | 2019-12-24 | 蚌埠学院 | Wireless bolt pretightening force sensor |
| CN112945435A (en) * | 2021-02-04 | 2021-06-11 | 包头盛泰汽车零部件制造有限公司 | Method for testing axial force of bolt for wheel |
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