CN117723191A - Stress calculation constant calibration method for measuring residual stress on surface of ceramic material - Google Patents
Stress calculation constant calibration method for measuring residual stress on surface of ceramic material Download PDFInfo
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Abstract
The invention discloses a stress calculation constant calibration method for measuring residual stress on the surface of a ceramic material. Strain readings in different directions of the strain gauge are recorded when target calibration samples before and after drilling are loaded to different tension values, and stress calculation constant calibration is performed according to the recorded strain readings, so that more accurate stress calculation constants are obtained, and the measurement of residual stress on the surface of the ceramic material is more accurate and scientific. Solves the problem that the prior art lacks a stress calculation constant calibration method for measuring the residual stress on the surface of the ceramic material.
Description
Technical Field
The invention relates to the technical field of material residual stress measurement, in particular to a stress calculation constant calibration method for measuring residual stress on the surface of a ceramic material.
Background
The drilling strain method is a common method for testing the residual stress of the surface of the metal material, and related regulations on the method for measuring the residual stress of the metal material are in the national standard GB/T31310-2014 drilling strain method for measuring the residual stress of the metal material, but related standard regulations on the measurement of the residual stress of the ceramic material are not available. The blind hole method is applied to the residual stress test of the ceramic surface at present, but the calibration of the stress calculation constant of the ceramic material is not involved. The conventional calibration method for the stress calculation constant of the metal material is not completely suitable for the ceramic material. For example, a calibration sample is formulated in a metal material, in order to eliminate residual stress in the sample as much as possible, mechanical processing is performed first, stress elimination annealing treatment is performed, new stress on the annealing surface is avoided, and the process is not applicable to ceramic materials; also for example: the requirements of limiting the size of the sample, such as the internal corners, the external grooves and the like of the outer contour of the sample, are also not applicable to ceramic materials; also for example: there are also cases where the calibration step is not suitable for ceramic materials. Currently, a stress calculation constant calibration method for measuring residual stress on the surface of a ceramic material is lacking.
Accordingly, there is a need for improvement and development in the art.
Disclosure of Invention
The invention aims to solve the technical problems of the prior art by providing a method for calibrating a stress calculation constant for measuring the residual stress on the surface of a ceramic material, and aims to solve the problem of lack of the method for calibrating the stress calculation constant for measuring the residual stress on the surface of the ceramic material in the prior art.
The technical scheme adopted by the invention for solving the problems is as follows:
in a first aspect, an embodiment of the present invention provides a method for calibrating a stress calculation constant for measuring residual stress on a surface of a ceramic material, where the method includes:
obtaining a target calibration sample, wherein the target calibration sample comprises a plurality of strain gauges stuck at preset intervals;
stretching the target calibration sample to a plurality of preset tension values through a material testing machine, and obtaining strain data of the tension values corresponding to each strain gauge aiming at each strain gauge, wherein each strain data comprises strain values corresponding to a plurality of directions respectively;
drilling the target calibration sample from the center of the strain gauge, and continuously executing the step of stretching the target calibration sample to a plurality of preset tension values by a material testing machine after drilling until the strain data of the tension values corresponding to each strain gauge after drilling are obtained;
calculating a stress calculation constant according to the strain data of each tension value for each strain gauge;
and determining the calibrated stress calculation constant according to each calculated stress calculation constant.
In one embodiment, the obtaining a target calibration sample includes:
firing a sample according to a material to be tested, wherein a heating curve and heat preservation time in a firing curve of the sample are consistent with those of the material to be tested;
slowly cooling the sample, cutting the sample according to a preset size requirement after cooling to normal temperature, and drying the cut sample to obtain a calibration sample;
and carrying out patch operation on the target calibration sample to obtain the target calibration sample.
In one embodiment, the patch operation includes:
and pasting strain gauges of the same type as those used for measuring residual stress at the middle position of the calibration sample, and pasting a plurality of strain gauges at preset intervals, wherein when the strain gauges are pasted, the directions of two mutually perpendicular resistance strain gauges are consistent with the length direction and the width direction of the calibration sample.
In one embodiment, clamping the target calibration sample prior to the material testing machine further comprises:
and pre-drilling the strain gauge on the target calibration sample.
In one embodiment, before the target calibration sample is stretched to a preset number of tension values by the material testing machine, the method further comprises:
clamping the target calibration sample on a material testing machine, and measuring whether strain output is stable or not;
if the strain output is stable, stretching the target calibration sample to a plurality of preset tension values;
and if the strain output is unstable, carrying out patch operation on the target calibration sample again.
In one embodiment, the plurality of tension values include tension values corresponding to 0.3 times material tensile strength, 0.5 times material tensile strength and 0.7 times material tensile strength of the calibration sample; each of the strain data includes strain values in at least two directions.
In one embodiment, said calculating a stress calculation constant from said strain data for each of said tension values comprises:
for each tension value, calculating the strain difference value corresponding to each direction according to the strain value of each direction corresponding to the tension value before and after drilling;
and obtaining the tensile stress corresponding to the target calibration sample, and calculating a stress calculation constant corresponding to the tensile stress value according to the strain difference values and the tensile stress in all directions.
In a second aspect, an embodiment of the present invention further provides a device for calibrating a stress calculation constant for measuring a residual stress on a surface of a ceramic material, where the device includes:
the sample acquisition module is used for acquiring a target calibration sample, wherein the target calibration sample comprises a plurality of strain gauges stuck at preset intervals;
the sample testing module is used for stretching the target calibration sample to a plurality of preset tension values through the material testing machine, and obtaining strain data of the tension values corresponding to each strain gauge aiming at each strain gauge, wherein each strain data comprises a plurality of strain values respectively corresponding to the directions;
drilling the target calibration sample from the center of the strain gauge, and continuously executing the step of stretching the target calibration sample to a plurality of preset tension values by a material testing machine after drilling until the strain data of the tension values corresponding to each strain gauge after drilling are obtained;
a constant calculation module for calculating a stress calculation constant for each strain gauge according to the strain data of each tension value;
and determining the calibrated stress calculation constant according to each calculated stress calculation constant.
In a third aspect, an embodiment of the present invention further provides a terminal, where the terminal includes a memory and more than one processor; the memory stores more than one program; the program comprising instructions for performing a method for calibrating a stress calculation constant for use in the determination of residual stress on a surface of a ceramic material as described in any of the above; the processor is configured to execute the program.
In a fourth aspect, embodiments of the present invention further provide a computer readable storage medium having stored thereon a plurality of instructions adapted to be loaded and executed by a processor to implement the steps of any of the above-described stress calculation constant calibration methods for determination of residual stress on a surface of a ceramic material.
The invention has the beneficial effects that: according to the embodiment of the invention, strain readings in different directions of the strain gauge are recorded when target calibration samples before and after drilling are loaded to different tension values, and stress calculation constant calibration is performed according to the recorded strain readings, so that a more accurate stress calculation constant is obtained, and the measurement of the residual stress on the surface of the ceramic material is more accurate and scientific. Solves the problem that the prior art lacks a stress calculation constant calibration method for measuring the residual stress on the surface of the ceramic material.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments described in the present invention, and other drawings may be obtained according to the drawings without inventive effort to those skilled in the art.
Fig. 1 is a schematic flow chart of a calibration method of stress calculation constants for measuring residual stress on the surface of a ceramic material according to an embodiment of the invention.
Fig. 2 is a schematic illustration of pasting a strain gauge according to an embodiment of the present invention.
FIG. 3 is a schematic block diagram of a calibration device for calculating a stress constant for measuring residual stress on a surface of a ceramic material according to an embodiment of the present invention.
Fig. 4 is a schematic block diagram of a terminal according to an embodiment of the present invention.
Detailed Description
The invention discloses a stress calculation constant calibration method for measuring residual stress on the surface of a ceramic material, which is used for making the purpose, the technical scheme and the effect of the invention clearer and more definite, and is further described in detail below by referring to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless expressly stated otherwise, as understood by those skilled in the art. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may also be present. Further, "connected" or "coupled" as used herein may include wirelessly connected or wirelessly coupled. The term "and/or" as used herein includes all or any element and all combination of one or more of the associated listed items.
It will be understood by those skilled in the art that 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 unless defined otherwise. 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.
Aiming at the defects in the prior art, the invention provides a stress calculation constant calibration method for measuring the residual stress on the surface of a ceramic material. Strain readings in different directions of the strain gauge are recorded when target calibration samples before and after drilling are loaded to different tension values, and stress calculation constant calibration is performed according to the recorded strain readings, so that more accurate stress calculation constants are obtained, and the measurement of residual stress on the surface of the ceramic material is more accurate and scientific. Solves the problem that the prior art lacks a stress calculation constant calibration method for measuring the residual stress on the surface of the ceramic material.
As shown in fig. 1, the method includes:
and S100, acquiring a target calibration sample, wherein the target calibration sample comprises a plurality of strain gauges stuck at preset intervals.
Specifically, the target calibration sample is manufactured based on a material to be measured, which may be a ceramic material. The target calibration sample is stuck with a plurality of strain gauges, and the interval distance between any two adjacent strain gauges is equal to the preset interval. The strain gage has two or more resistance strain gages with different axial sensitive grids, and can be used for determining the magnitude and direction of main strain in a plane stress field. And then, testing the target calibration sample, and calculating a stress calculation constant for measuring the residual stress of the surface of the material to be tested according to the test data.
In one implementation manner, the obtaining the target calibration sample specifically includes:
firing a sample according to a material to be tested, wherein a heating curve and heat preservation time in a firing curve of the sample are consistent with those of the material to be tested;
slowly cooling the sample, cutting the sample according to a preset size requirement after cooling to normal temperature, and drying the cut sample to obtain a calibration sample;
and carrying out patch operation on the target calibration sample to obtain the target calibration sample.
Specifically, a sample is fired according to a material to be tested, and heating conditions and cooling conditions in the firing process are limited, so that the influence of residual stress on the surface of the sample on the accuracy of coefficient calibration is reduced. And then cutting the sample cooled to normal temperature according to preset size requirements, for example, cutting according to a certain size length, width and thickness. And after cutting, placing the sample in a drying oven to be dried according to a specific temperature and a specific time length, and obtaining the calibration sample after drying. Since the calibration sample is required to be subjected to strain testing, it is also required to perform a patch operation on the calibration sample, and a plurality of strain gages are stuck on the calibration sample at predetermined intervals.
For example, the material used for calibrating the sample should be the same as the material to be measured, the fired sample has a dimension of 300mm in length and a width of greater than 50mm, and the thickness is consistent with the thickness of the material to be measured. When the sample is fired, the temperature rising curve and the heat preservation time in the firing curve are consistent with those of the material to be tested; in the cooling process, slow cooling is adopted, for example, a normally closed furnace door is adopted for power-off cooling, or the cooling rate is set to be smaller than 20 ℃/min. After the sample is cooled to normal temperature, the sample is cut by a cutting machine, and the edges at the two sides are cut along the width direction, so that the final width is within 30+/-1 mm, and the length direction is 300mm. After excision, the sample is dried in a drying oven at a temperature higher than 180 ℃ for more than 1 hour.
In one implementation, the paster operation includes:
and pasting strain gauges of the same type as those used for measuring residual stress at the middle position of the calibration sample, and pasting a plurality of strain gauges at preset intervals, wherein when the strain gauges are pasted, the directions of two mutually perpendicular resistance strain gauges are consistent with the length direction and the width direction of the calibration sample.
Specifically, the strain gauge of the same type as that used for residual stress measurement is used for adhesion to the calibration sample in this embodiment, and strain gauge, particularly type a strain gauge, may be used. For more accurate calculation results, the ceramic surface of the calibration sample may be polished before pasting, for example, by laser polishing or sand polishing, and then dedusted after polishing, for example, by wiping with cotton dipped with a little methanol. And sticking the strain gauge at the middle position of the calibration sample, and sticking a plurality of strain gauges, wherein the distance between each strain gauge and each strain gauge is determined according to a preset interval, for example, 3 strain gauges and more are stuck, and the distance between each strain gauge and each strain gauge is larger than 30mm. When the strain gauge is adhered, the directions of the two mutually perpendicular resistance strain gauges are consistent with the length direction and the width direction of the calibration sample, so that the influence on the subsequent calibration process of the stress calculation constant is avoided.
As shown in fig. 1, the method further includes:
step 200, stretching the target calibration sample to a preset plurality of tension values through a material testing machine, and obtaining strain data of the tension values corresponding to each strain gauge aiming at each strain gauge, wherein each strain data comprises a plurality of strain values respectively corresponding to directions.
Specifically, after the target calibration sample is obtained, the target calibration sample is clamped on a material testing machine for strain testing. And loading corresponding material tensile strength to the target calibration sample according to a plurality of predetermined tension values, recording the strain values of the strain gauge in different directions when the strain gauge is at different tension values for each strain gauge on the target calibration sample, wherein the recorded strain values are used as basic calculation data for calibrating the stress calculation constant subsequently.
In one implementation, a method for clamping a target calibration sample on a material testing machine includes: a flexible gasket is arranged between the jaw piece and the target calibration sample through a wedge-shaped clamp, the gasket is made of polyvinyl chloride (PVC), the front surface and the back surface are provided with anti-skid patterns, and the thickness of the gasket is 1-2 mm.
In one implementation, clamping the target calibration sample before the material testing machine further comprises pre-drilling a strain gauge on the target calibration sample.
In particular, strain gages are capable of measuring strain from static to dynamic, as well as shock induced strain. The purpose of this example is to release the surface stress of the target calibration sample by means of surface drilling and to measure the strain relaxation before and after drilling with pre-glued strain gages. The strain gauge may have an influence on the surface stress of the target calibration sample during drilling, so in order to more accurately measure the strain before and after stress release, the strain gauge may be pre-drilled in this embodiment.
For example, taking a strain gauge as an example, placing a target calibration sample in the working range of a laser engraving machine, moving the target calibration sample to enable the center of the strain gauge to coincide with the focusing beam of the laser, running a pre-drilling program, engraving a hole with a diameter slightly larger than that of a subsequent strain test drilling hole (for example, the strain test drilling hole is 1.8mm in diameter, and the strain gauge pre-drilling hole is 2.2 mm) at the center of the strain gauge, and repeating for a plurality of times until the strain gauge is just perforated.
In one implementation, before the target calibration sample is stretched to a preset number of tension values by the material testing machine, the method further includes:
clamping the target calibration sample on a material testing machine, and measuring whether strain output is stable or not;
if the strain output is stable, stretching the target calibration sample to a plurality of preset tension values;
and if the strain output is unstable, carrying out patch operation on the target calibration sample again.
Specifically, in order to obtain a more accurate strain amount, the embodiment needs to detect the stability of the strain output before strain testing the target calibration sample, and only when the stability of the strain output meets the requirement, the strain testing is performed on the target calibration sample, otherwise, the patch operation needs to be performed on the target calibration sample again.
For example, a target calibration sample is mounted on a material testing machine, and the measurement leads are connected to strain gauges for zeroing, powered up, and loaded to a specific material tensile strength (Rm), for example 0.5Rm. And then unloaded and reloaded to a specific material tensile strength, namely repeated 1 time, and the stability of strain output is observed. If the data is stable, i.e. the unloaded strain is basically restored to the initial value (the maximum error is smaller than 10 mu epsilon), the target calibration sample can be subjected to strain test, otherwise, the target calibration sample needs to be subjected to patch operation again.
In one implementation, the plurality of tension values include tension values corresponding to 0.3 times material tensile strength, 0.5 times material tensile strength and 0.7 times material tensile strength of the calibration sample; each of the strain data includes strain values in at least two directions.
Specifically, in the embodiment, when the strain test is set, the calibration sample needs to be stretched to a tensile value corresponding to 0.3Rm, 0.5Rm and 0.7Rm, a strain reading is obtained through the strain gauge, and the strain values of at least two directions of each strain gauge when the strain gauge is loaded to each tensile value are recorded, for example, the strain values of the target calibration sample in the length direction and the width direction can be selectively recorded; alternatively, the length direction and width direction of the target calibration sample may be selected, and the direction may be positioned at an angle of 45 degrees between the length direction and the width direction (as shown in fig. 2).
After the calibration sample is clamped on a wedge-shaped clamp and pre-tightened, selecting unloading load on an operation interface of a material testing machine, and clearing strain readings when the load is unloaded to be within 10N; the material testing machine stretches the calibration sample according to a preset loading speed (for example, lower than 0.2 mm/min), three tension values of 0.3Rm, 0.5Rm and 0.7Rm are respectively set, and when the load respectively reaches the two tension values of 0.3Rm and 0.5Rm, the retention force is stable for more than a preset time period and is continuously increased; slowly unloading after the tension value of 0.7Rm is kept for more than a preset time, wherein the preset time can be set to be 30s; reading strain in three directions during stabilization of force acquired by strain gaugesNumerical values, average values of more than a plurality of continuous numerical values (for example, 5 continuous numerical values) in the force-taking stable period are respectively recorded as epsilon 1 0 、ε 2 0 、ε 3 0 The method comprises the steps of carrying out a first treatment on the surface of the Correspondingly, the three tension values can be respectively obtained three times epsilon 1 0 、ε 2 0 、ε 3 0 。
As shown in fig. 1, the method further includes:
and step S300, drilling the target calibration sample from the center of the strain gauge, and continuously executing the step of stretching the target calibration sample to a plurality of preset tension values by the material testing machine after drilling until the strain data of the tension values corresponding to each strain gauge after drilling are obtained.
Specifically, in this embodiment, the surface stress of the target calibration sample is released by surface drilling, when drilling, the strain gauge is drilled from the center, and if the strain gauge passes through the pre-drilling, the hole generated by the pre-drilling can be drilled. After the drilling is completed, the strain test is performed again on the drilled target calibration sample (i.e. step S200 is performed), so that strain relaxation before and after the drilling of the target calibration sample, i.e. strain data before and after the stress release, is obtained.
For example, the target calibration sample is detached from the material testing machine and placed in the working range of the laser engraving machine, the target calibration sample is moved to enable the center of the strain gauge to coincide with the focusing beam of the laser, a drilling program for residual stress measurement is operated, drilling is carried out on the center of the strain gauge on the surface of the target calibration sample, and the drilling diameter and depth are kept consistent with the subsequent stress measurement test conditions (for example, the drilling diameter is 1.8mm, and the depth is 1.5 mm). After drilling, the target calibration sample is reinstalled to the material testing machine, the measuring wire is connected to the strain gauge, the steps of strain testing are repeated, and the average value of more than a plurality of continuous values in the same stress stabilizing period is calculated and respectively recorded as epsilon 1 ′、ε 2 ′、ε 3 'A'; correspondingly, the three tension values can be respectively obtained three times epsilon 1 ′、ε 2 ′、ε 3 ′。
Step 400, calculating a stress calculation constant according to the strain data of each tension value for each strain gauge.
Specifically, for each strain gauge, the embodiment analyzes the strain conditions before and after the surface stress release of the target calibration sample according to the strain data recorded by the strain gauges before and after drilling, so as to calculate the stress calculation constant. The strain data of each tension value on each strain gauge can be independently used for calculating the stress calculation constant, so that a plurality of calculated values of the stress calculation constant can be obtained.
In one implementation, the calculating a stress calculation constant from the strain data for each of the tension values includes:
for each tension value, calculating the strain difference value corresponding to each direction according to the strain value of each direction corresponding to the tension value before and after drilling;
and obtaining the tensile stress corresponding to the target calibration sample, and calculating a stress calculation constant corresponding to the tensile stress value according to the strain difference values and the tensile stress in all directions.
Specifically, the strain data of each strain gauge includes strain values of different tensile force values in different directions before and after drilling, and in this embodiment, a stress calculation constant is calculated for each tensile force value to obtain a plurality of calculated values of the stress calculation constant. Taking a tensile force value as an example, calculating the strain difference before and after drilling in each direction by using the strain values recorded before and after drilling in each direction by the tensile force value, for example, subtracting the strain value before drilling from the strain value after drilling in the direction for one direction to obtain the strain difference in the direction. And then, the tensile stress born by the target calibration sample is obtained, and the stress calculation constant corresponding to the tensile stress value is calculated by combining the strain difference values before and after drilling in all directions.
For example, take a tensile force value as an example, the strain data of the tensile force value includes ε 1 、ε 2 、ε 3 The strain values of the three directions before drilling are marked as epsilon 1 0 、ε 2 0 、ε 3 0 And the strain values of the three directions after drilling are marked as epsilon 1 ′、ε 2 ′、ε 3 ' the strain difference in three directions is denoted as delta epsilon 1 、Δε 2 、Δε 3 . Alternatively, the strain data for the tension value includes ε 1 、ε 3 The strain values of the two directions before drilling are marked as epsilon 1 0 、ε 3 0 And the strain values of the two directions after drilling are marked as epsilon 1 ′、ε 3 ' the strain difference in both directions is denoted as delta epsilon 1 、Δε 3 Wherein ε is 1 、ε 3 Respectively correspond to the length direction and the width direction of the target calibration sample, namely epsilon 1 、ε 3 The two directions are perpendicular to each other.
The strain calculation constants comprise A, B constants, and the strain calculation constants corresponding to the tension values can be obtained by respectively carrying out A, B constant calculation processes on the strain data read by the tension values.
A. The calculation formula of the B constant is as follows:
wherein sigma is the tensile stress born by the target calibration sample:
wherein F is a maintained tension value, b is the width of the target calibration sample, h is the thickness of the target calibration sample, and the values of b and h are averaged (for example, more than 3 times) through a plurality of measurements.
As shown in fig. 1, the method further includes:
and S500, determining the calibrated stress calculation constants according to the calculated stress calculation constants.
Specifically, in this embodiment, the calculation processes of the stress calculation constants are performed on different strain gages, so as to obtain a plurality of calculation values of the stress calculation constants, and the calibrated stress calculation constants are determined comprehensively by the plurality of calculation values of the stress calculation constants.
For example, the stress calculation constants include A, B constants, and A, B constants are calculated according to the strain data before and after drilling of different strain gauges, so as to obtain a plurality of calculated values of A, B constants; and screening the A, B constant obtained by multiple calibration to remove an abnormal result, and calculating an average value to obtain the A, B constant finally calibrated. In order to improve the accuracy and reliability of the data, the calculation process of the stress calculation constant should be repeated for different strain gauges multiple times (for example, at least 2 times), and if the relative error of the calculation results of the multiple times exceeds a preset error threshold (for example, 10%), the calculation results should be recalibrated.
The invention has the advantages that:
1. the invention provides a stress calculation constant calibration method for measuring the residual stress on the surface of a ceramic material, which solves the defects of the prior art and ensures that the measurement of the residual stress on the surface of the ceramic material is more accurate and scientific.
2. The invention limits the firing cooling condition and the cooling rate, and can reduce the influence of the residual stress on the surface of the calibration sample on the accuracy of coefficient calibration.
3. The invention provides a clamping method of a calibration sample in a material testing machine and required auxiliary materials, which avoid excessive slip between a clamp piece and the calibration sample caused by clamping damage to the calibration sample and insufficient clamping force in the clamping process.
4. According to the method, before drilling the calibration sample, the strain gauge is pre-drilled, and the finally obtained stress calculation constant is the result obtained by the strain difference of the strain gauge under the condition of the same tensile stress caused by the change of the sample before and after drilling, so that the influence of the strain gauge drilling on the zero point of the strain gauge is removed.
5. According to the invention, the load is unloaded through the operation of the material testing machine, so that the zero point of the strain gauge can be positioned more accurately until the external force of the sample is small; and secondly, the method for calculating the average value of the strain values by keeping the force value for a period of time and solving the average value of the strain values by more than a plurality of continuous values in the force taking stable period ensures that the strain values are more representative and the coefficient accuracy is improved.
Based on the above embodiment, the present invention further provides a device for calibrating a stress calculation constant for measuring residual stress on a surface of a ceramic material, as shown in fig. 3, where the device includes:
the sample acquisition module 01 is used for acquiring a target calibration sample, wherein the target calibration sample comprises a plurality of strain gauges stuck at preset intervals;
the sample testing module 02 is configured to stretch the target calibration sample to a preset plurality of tensile values by using a material testing machine, and obtain, for each strain gauge, strain data of each tensile value corresponding to the strain gauge, where each strain data includes a strain value corresponding to a plurality of directions respectively;
drilling the target calibration sample from the center of the strain gauge, and continuously executing the step of stretching the target calibration sample to a plurality of preset tension values by a material testing machine after drilling until the strain data of the tension values corresponding to each strain gauge after drilling are obtained;
a constant calculation module 03 for calculating a stress calculation constant for each strain gauge according to the strain data of each tension value;
and determining the calibrated stress calculation constant according to each calculated stress calculation constant.
Based on the above embodiment, the present invention also provides a terminal, whose functional block diagram is shown in fig. 4. The terminal comprises a processor, a memory, a network interface and a display screen which are connected through a system bus. Wherein the processor of the terminal is adapted to provide computing and control capabilities. The memory of the terminal includes a nonvolatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The network interface of the terminal is used for communicating with an external terminal through a network connection. The computer program is executed by a processor to implement a stress calculation constant calibration method for determination of residual stress on a surface of a ceramic material. The display screen of the terminal may be a liquid crystal display screen or an electronic ink display screen.
It will be appreciated by those skilled in the art that the functional block diagram shown in fig. 4 is merely a block diagram of some of the structures associated with the present inventive arrangements and is not limiting of the terminal to which the present inventive arrangements may be applied, and that a particular terminal may include more or less components than those shown, or may combine some of the components, or have a different arrangement of components.
In one implementation, the memory of the terminal has one or more programs stored therein, and configuring one or more processors to execute the one or more programs includes instructions for performing a stress calculation constant calibration method for ceramic material surface residual stress determination.
Those skilled in the art will appreciate that implementing all or part of the above described methods may be accomplished by way of a computer program stored on a non-transitory computer readable storage medium, which when executed, may comprise the steps of the embodiments of the methods described above. Any reference to memory, storage, database, or other medium used in embodiments provided herein may include non-volatile and/or volatile memory. The nonvolatile memory can include Read Only Memory (ROM), programmable ROM (PROM), electrically Programmable ROM (EPROM), electrically Erasable Programmable ROM (EEPROM), or flash memory. Volatile memory can include Random Access Memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms such as Static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double Data Rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous Link DRAM (SLDRAM), memory bus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), among others.
In summary, the invention discloses a method for calibrating a stress calculation constant for measuring residual stress on the surface of a ceramic material, which comprises the following steps: obtaining a target calibration sample, wherein the target calibration sample comprises a plurality of strain gauges stuck at preset intervals; stretching the target calibration sample to a plurality of preset tension values through a material testing machine, and obtaining strain data of the tension values corresponding to each strain gauge aiming at each strain gauge, wherein each strain data comprises strain values corresponding to a plurality of directions respectively; drilling the target calibration sample from the center of the strain gauge, and continuously executing the step of stretching the target calibration sample to a plurality of preset tension values by a material testing machine after drilling until the strain data of the tension values corresponding to each strain gauge after drilling are obtained; calculating a stress calculation constant according to the strain data of each tension value for each strain gauge; and determining the calibrated stress calculation constant according to each calculated stress calculation constant. According to the invention, strain readings in different directions of the strain gauge are recorded when target calibration samples before and after drilling are loaded to different tension values, and stress calculation constant calibration is performed according to the recorded strain readings, so that a more accurate stress calculation constant is obtained, and the measurement of the residual stress on the surface of the ceramic material is more accurate and scientific. Solves the problem that the prior art lacks a stress calculation constant calibration method for measuring the residual stress on the surface of the ceramic material.
It is to be understood that the invention is not limited in its application to the examples described above, but is capable of modification and variation in light of the above teachings by those skilled in the art, and that all such modifications and variations are intended to be included within the scope of the appended claims.
Claims (10)
1. A method for calibrating a stress calculation constant for measuring residual stress on a surface of a ceramic material, the method comprising:
obtaining a target calibration sample, wherein the target calibration sample comprises a plurality of strain gauges stuck at preset intervals;
stretching the target calibration sample to a plurality of preset tension values through a material testing machine, and obtaining strain data of the tension values corresponding to each strain gauge aiming at each strain gauge, wherein each strain data comprises strain values corresponding to a plurality of directions respectively;
drilling the target calibration sample from the center of the strain gauge, and continuously executing the step of stretching the target calibration sample to a plurality of preset tension values by a material testing machine after drilling until the strain data of the tension values corresponding to each strain gauge after drilling are obtained;
calculating a stress calculation constant according to the strain data of each tension value for each strain gauge;
and determining the calibrated stress calculation constant according to each calculated stress calculation constant.
2. The method for calibrating a stress calculation constant for measuring residual stress on a surface of a ceramic material according to claim 1, wherein the step of obtaining a target calibration sample comprises the steps of:
firing a sample according to a material to be tested, wherein a heating curve and heat preservation time in a firing curve of the sample are consistent with those of the material to be tested;
slowly cooling the sample, cutting the sample according to a preset size requirement after cooling to normal temperature, and drying the cut sample to obtain a calibration sample;
and carrying out patch operation on the target calibration sample to obtain the target calibration sample.
3. The method for calibrating a stress calculation constant for measuring residual stress on a surface of a ceramic material according to claim 2, wherein the attaching operation comprises:
and pasting strain gauges of the same type as those used for measuring residual stress at the middle position of the calibration sample, and pasting a plurality of strain gauges at preset intervals, wherein when the strain gauges are pasted, the directions of two mutually perpendicular resistance strain gauges are consistent with the length direction and the width direction of the calibration sample.
4. The method for calibrating a stress calculation constant for measuring residual stress on a surface of a ceramic material according to claim 1, wherein clamping the target calibration sample before the material testing machine further comprises:
and pre-drilling the strain gauge on the target calibration sample.
5. The method for calibrating a stress calculation constant for measuring residual stress on a ceramic material surface according to claim 1, wherein the method further comprises, before the target calibration sample is stretched to a preset number of tensile values by a material testing machine:
clamping the target calibration sample on a material testing machine, and measuring whether strain output is stable or not;
if the strain output is stable, stretching the target calibration sample to a plurality of preset tension values;
and if the strain output is unstable, carrying out patch operation on the target calibration sample again.
6. The method for calibrating a stress calculation constant for measuring residual stress on a ceramic material surface according to claim 1, wherein the plurality of tension values include tension values corresponding to a calibration sample subjected to 0.3 times of material tensile strength, 0.5 times of material tensile strength and 0.7 times of material tensile strength, respectively; each of the strain data includes strain values in at least two directions.
7. The method for calibrating a stress calculation constant for measuring residual stress on a surface of a ceramic material according to claim 1, wherein said calculating a stress calculation constant from said strain data for each of said tension values comprises:
for each tension value, calculating the strain difference value corresponding to each direction according to the strain value of each direction corresponding to the tension value before and after drilling;
and obtaining the tensile stress corresponding to the target calibration sample, and calculating a stress calculation constant corresponding to the tensile stress value according to the strain difference values and the tensile stress in all directions.
8. A stress calculation constant calibration device for measuring residual stress on the surface of a ceramic material, the device comprising:
the sample acquisition module is used for acquiring a target calibration sample, wherein the target calibration sample comprises a plurality of strain gauges stuck at preset intervals;
the sample testing module is used for stretching the target calibration sample to a plurality of preset tension values through the material testing machine, and obtaining strain data of the tension values corresponding to each strain gauge aiming at each strain gauge, wherein each strain data comprises a plurality of strain values respectively corresponding to the directions;
drilling the target calibration sample from the center of the strain gauge, and continuously executing the step of stretching the target calibration sample to a plurality of preset tension values by a material testing machine after drilling until the strain data of the tension values corresponding to each strain gauge after drilling are obtained;
a constant calculation module for calculating a stress calculation constant for each strain gauge according to the strain data of each tension value;
and determining the calibrated stress calculation constant according to each calculated stress calculation constant.
9. A terminal comprising a memory and one or more processors; the memory stores more than one program; the program comprising instructions for performing the method for calibrating a stress calculation constant for determination of residual stress on a surface of a ceramic material according to any one of claims 1 to 7; the processor is configured to execute the program.
10. A computer readable storage medium having stored thereon a plurality of instructions adapted to be loaded and executed by a processor to carry out the steps of the method for calibrating a stress calculation constant for use in the determination of residual stress on a surface of a ceramic material according to any of the preceding claims 1-7.
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| CN118980570A (en) * | 2024-08-02 | 2024-11-19 | 东莞市唯美陶瓷工业园有限公司 | Stress calculation constant calibration method, device, terminal and storage medium for drilling method |
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| CN118980570A (en) * | 2024-08-02 | 2024-11-19 | 东莞市唯美陶瓷工业园有限公司 | Stress calculation constant calibration method, device, terminal and storage medium for drilling method |
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