CN101373173A - Method and apparatus for testing brittle material strength - Google Patents
Method and apparatus for testing brittle material strength Download PDFInfo
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- CN101373173A CN101373173A CNA2008101370195A CN200810137019A CN101373173A CN 101373173 A CN101373173 A CN 101373173A CN A2008101370195 A CNA2008101370195 A CN A2008101370195A CN 200810137019 A CN200810137019 A CN 200810137019A CN 101373173 A CN101373173 A CN 101373173A
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Abstract
The invention relates to a device and a method for determining the strength of a brittle material. The invention adopts a method of biaxial bending and loading as follows: a disc-shaped sample and concentric ring clamps are selected and loaded on an electronic universal tester; the upper circular section and the lower circular section of the sample are taken as a loading surface and a support surface correspondingly; the two concentric ring sample clamps of different sizes are selected to fix the disc-shaped sample at the top and the bottom in order to perform biaxial bending; and a proper stress analysis is adopted to calculate and obtain the corresponding rupture strength value and the bending strength value. The invention provides the novel method and the relative device for determining the bending strength of the brittle material; the disc-shaped sample, the concentric ring clamps, a graphite gasket and a barrel-shaped positioning and guiding device are selected to perform biaxial loading for the disc-shaped sample on a conventional Instron-1186 electronic universal tester; and the invention has the advantages of easy sample processing, simple testing device and more reliable experimental results.
Description
(1) technical field
The present invention relates to strength of materials measuring technique, be specifically related to a kind of method of testing of brittle material strength.
(2) background technology
Hard brittle materials such as glass, pottery, concrete, crystal have obtained using widely at present in national economy and national defence.The fracture strength of material is the important references index of the actual usability of material, but intensity is not intrinsic parameters, and it is all multifactor relevant with sample surfaces crudy, method of testing and specimen size etc.Thereby how to measure more exactly that the fracture strength of hard brittle material has important theory and using value under the service condition.
The tensile strength of measuring hard brittle material is relatively more difficult, mainly be because hard brittle material is hard and crisp, be difficult to process complex-shaped stretching standard sample, and require experimental machine to have high concentricity, so mainly to measure the hard brittle material bending strength as the index of estimating its strength character.All there are not a kind of easy, brittle material strength method of testing and tester accurately at present both at home and abroad, common bending strength test three-point bending or the four-point bending methods of adopting more, select the sample of long bar-shaped square-section for use, thereby also exist seamed edge to need chamfering to prevent difficult points such as stress is concentrated, manufacturing procedure complexity, in addition in order to overcome the relatively poor shortcoming of test findings repeatability, every group of measurement generally needs the sample of a greater number (generally greater than 10), and carries out the statistical study that Vickers distributes.
In addition for monocrystal material, the characteristics that have the crystalline anisotropy, and in common 3 or four-point bending method test the general long bar-shaped square-section samples that adopt more, even thereby the loading of same crystal face sample, if the crystal face difference of sample side, test findings all has very big difference, thereby is difficult to set up unified evaluation of material system.In addition, 3 or the very difficult true stress that reflects material at some certain applications such as optical window of four-point bending test.
(3) summary of the invention
The object of the present invention is to provide a kind of sample handling ease, proving installation is easy, test findings is more reliable relatively, simplified the specimen preparation step, be beneficial to the test specimen that processes great surface quality, and more suitable loading stress analysis and the intensity calculating that is applicable to ceramic-like crystal and optical window field usefulness material, set up necessary resistive heating device on this external sample stage, also can make things convenient for the method that is used for testing brittle material strength of testing brittle material alternating temperature intensity size.
The object of the present invention is achieved like this: by the mode of twin shaft to the bending loading, select disc shaped test piece, concentric ring anchor clamps for use, on the electronic universal experimental machine, load, the circular section up and down of sample is as corresponding loading surface and supporting surface, select the two concentric ring specimen holders that vary in size for use, fixing up and down to sample, carry out twin shaft to bending, adopt corresponding stress analysis to calculate corresponding fracture bending strength value.
Method of testing of the present invention also has some technical characterictics like this:
1, described disc shaped test piece is non-common strip standard model, when analyzing the intensity size of its stress state calculating sample, adopts following formula:
Wherein: F is the size of add load, and t is a sample thickness; d
sBe the mean diameter of last loaded ring, d
lBe the mean diameter of lower support ring, d is the mean diameter of sample, and v is the Poisson ratio of sample.
Another object of the present invention is to provide a kind of device that is used for testing brittle material strength of realizing above-mentioned method of testing, it comprises disc shaped test piece, concentric ring anchor clamps and electronic universal experimental machine, the concentric ring anchor clamps comprise the concentric ring anchor clamps that vary in size, sample forms " sandwich " structure in the middle of two concentric rings, wherein big concentric ring is placed on the below of sample, and its upper end is used to support sample, and the other end is at base seal, little concentric ring is placed on the top of sample, at upper end closed.
The device of testing brittle material strength of the present invention also has some technical characterictics like this:
1, corresponding loading surface of circular section conduct and supporting surface about the described disc shaped test piece, and carry out necessary grinding and polishing;
2, the physical strength of described concentric ring clamp material should be higher than sample to be tested, and big or small concentric ring all passes through chamfered;
3, described disc shaped test piece and place the lubricated graphite paper of use up and down between the concentric ring respectively, the size of pad should be respectively greater than concentric rings, and all less than the diameter above sample.
The present invention relates to a kind of method and relevant apparatus thereof of testing brittle material strength, especially can be applicable to the mensuration of brittle material strength, be specially and select disc shaped test piece, concentric ring anchor clamps for use, by the mode of twin shaft to the bending loading, and then the bending strength of test and calculating fragility sample.The intensity of measuring hard brittle material at present adopts or four-point bending method at 3, yet because hard brittle material is general hard and crisp, is difficult for processing, is difficult to obtain the strip standard sample of higher crudy, and causes stress to concentrate easily in loading procedure.The processing cost that causes thus is excessive in order to overcome, the repeated relevant issues such as very poor of test findings, the present invention has designed a kind of method and relevant apparatus of new twin shaft crooked test hard brittle material bending strength, on common Instron-1186 electronic universal experimental machine, select disc shaped test piece, concentric ring anchor clamps, Graphite pad and supporting tubular locating guide device for use, sample is carried out twin shaft to loading; The sample handling ease, proving installation is easy, and test findings is more reliable relatively.
Fundamental purpose of the present invention is the method and the relevant apparatus thereof of the easy testing brittle material bending strength of a kind of energy of design, be different from common or four-point bending Loading Method at 3, but select disc shaped test piece, concentric ring anchor clamps for use, to the mode that bending loads, adopt corresponding stress analysis to calculate corresponding fracture bending strength value by twin shaft.The method has been simplified the specimen preparation step, be beneficial to the test specimen that processes great surface quality, and calculate with the loading stress analysis and the intensity of material in more suitable ceramic-like crystal and the optical window field of being applicable to, set up necessary resistive heating device on this external sample stage, also can make things convenient for the size of testing brittle material alternating temperature intensity.
Technical characterstic of the present invention has:
1, a kind of method of testing brittle material bending strength and relevant apparatus thereof, this method to the mode that bending loads, is selected disc shaped test piece, concentric ring anchor clamps by twin shaft for use, adopts corresponding stress analysis to calculate corresponding fracture bending strength value.
2, sample is selected the shape of disk for use, and the circular section up and down of sample is as corresponding loading surface and supporting surface, and carries out necessary grinding and polishing, with defective effect sample testing results' such as the micropore of avoiding the surface as far as possible, crackle accuracy.
3, select the two concentric ring specimen holders that vary in size for use, the physical strength of clamp material should be higher than sample to be tested, and big or small concentric ring all passes through chamfered, to avoid causing in the test process stress concentration phenomenon of sample.Sample forms " sandwich " structure in the middle of two concentric rings, wherein big concentric ring is placed on the below of sample, and its upper end is used to support sample, and the other end is at base seal; And little concentric ring is placed on the top of sample, at upper end closed, is used to transmit the loaded load of sample; And, require to load the sizableness of backing plate with sample in order to guarantee the concentricity of loaded ring and sample.
4, other stress concentration phenomenon in order further to prevent from loading procedure, to occur, at sample and place the lubricated graphite paper of using up and down between the concentric ring respectively, the size of pad should be respectively greater than concentric ring, but all can not surpass the diameter of sample simultaneously again, can further avoid the stress concentration phenomenon that occurs in the loading procedure.
(4) description of drawings
Fig. 1 is a specific embodiment experimental provision synoptic diagram;
Fig. 2 is the twin shaft bending strength of sapphire crystal under the different temperatures.
(5) embodiment
The present invention is further illustrated below in conjunction with the drawings and specific embodiments:
The mode that present embodiment loads to bending by twin shaft, select disc shaped test piece, concentric ring anchor clamps for use, on the electronic universal experimental machine, load, the circular section up and down of sample is as corresponding loading surface and supporting surface, select the two concentric ring specimen holders that vary in size for use, fixing up and down to sample, carry out twin shaft to bending, adopt corresponding stress analysis to calculate corresponding fracture bending strength value.Disc shaped test piece is non-common strip standard model, when analyzing the intensity size of its stress state calculating sample, adopts following formula:
Wherein: F is the size of add load, and t is a sample thickness; d
sBe the mean diameter of last loaded ring, d
lBe the mean diameter of lower support ring, d is the mean diameter of sample, and v is the Poisson ratio of sample.
The present embodiment device comprises disc shaped test piece, concentric ring anchor clamps and electronic universal experimental machine, the concentric ring anchor clamps comprise the concentric ring anchor clamps that vary in size, sample forms " sandwich " structure in the middle of two concentric rings, wherein big concentric ring is placed on the below of sample, its upper end is used to support sample, the other end is at base seal, and little concentric ring is placed on the top of sample, at upper end closed.Disc shaped test piece is corresponding loading surface of circular section conduct and supporting surface up and down, and carries out necessary grinding and polishing; The physical strength of concentric ring clamp material should be higher than sample to be tested, and big or small concentric ring all passes through chamfered; Disc shaped test piece and place the lubricated graphite paper of use up and down between the concentric ring respectively, the size of pad should be respectively greater than concentric rings, and all less than the diameter above sample.
Sapphire crystal has excellent optical property, mechanical property and chemical stability, and the intensity height, hardness is big, anti-washes away, and can work under the mal-condition of high temperature, thereby be widely used in a plurality of fields of the army and the people.Take a sample on the same blank of sapphire, the intensity level that records after the different processing technologys of process is all incomplete same, as seen this complex nature of the problem.Adopt this patent twin shaft bending method test intensity, for common ceramic-like optical window material such as sapphire crystal, magnesium aluminate spinel, be easier to process high-quality specimen surface, thereby improved sample testing result's accuracy and repeatability.
In conjunction with Fig. 1, present embodiment is selected high-intensity silit mould for use, and the concentric ring specimen holder comprises mould upper press ring 1 and lower support ring 2, and wherein the mean diameter of mould upper press ring is Φ 10mm, and the mean diameter of lower support ring is Φ 28mm.All fill up the thick graphite paper of last layer 0.6mm 3 between sample 4 and the mould.Experiment is to carry out on Instron-1186 electronic universal experimental machine, and sample is of a size of Φ 36mm * 2.0mm, and loading speed is 0.5mm/min, and the temperature range of test is 20～800 ℃.
Measure in the experimentation of material bending intensity at the twin shaft bending method, the sample upper surface is subjected to compressive stress, and lower surface is subjected to tension.When load reaches a certain particular value, often produce and destroy, thereby cause the material fracture at the stretching face of sample.Show that by the theoretical analysis to its stress state the stress that material is subjected to has radial stress and two vertical components of circumference stress, its numerical value equates in the loaded ring scope and reaches maximal value.
Actual measurement sapphire twin shaft bending strength value is shown in Fig. 2, and institute's data of surveying and bibliographical information are identical fine.
Claims (6)
1. method that is used for testing brittle material strength, it is characterized in that by the mode of twin shaft to the bending loading, select disc shaped test piece, concentric ring anchor clamps for use, on the electronic universal experimental machine, load, the circular section up and down of sample is selected the two concentric ring specimen holders that vary in size for use as corresponding loading surface and supporting surface, and is fixing up and down to sample, carry out twin shaft to bending, adopt corresponding stress analysis to calculate corresponding fracture bending strength value.
2. a kind of method that is used for testing brittle material strength according to claim 1 is characterized in that described disc shaped test piece is non-common strip standard model, when analyzing the intensity size of its stress state calculating sample, adopts following formula:
Wherein: F is the size of add load, and t is a sample thickness; d
sBe the mean diameter of last loaded ring, d
lBe the mean diameter of lower support ring, d is the mean diameter of sample, and v is the Poisson ratio of sample.
3. one kind is used to realize the described device that is used for the method for testing brittle material strength of claim 1, it is characterized in that it comprises disc shaped test piece, concentric ring anchor clamps and electronic universal experimental machine, the concentric ring anchor clamps comprise the concentric ring anchor clamps that vary in size, sample forms " sandwich " structure in the middle of two concentric rings, wherein big concentric ring is placed on the below of sample, and its upper end is used to support sample, and the other end is at base seal, little concentric ring is placed on the top of sample, at upper end closed.
4. the device that is used for testing brittle material strength according to claim 3 is characterized in that described disc shaped test piece corresponding loading surface of circular section conduct and supporting surface up and down, and carries out necessary grinding and polishing.
5. the device that is used for testing brittle material strength according to claim 4 it is characterized in that the physical strength of described concentric ring clamp material should be higher than sample to be tested, and big or small concentric ring all passes through chamfered.
6. according to the described device that is used for testing brittle material strength of claim 5, it is characterized in that described disc shaped test piece and place the lubricated graphite paper of using up and down between the concentric ring respectively, the size of pad should be respectively greater than concentric ring, and all less than the diameter that surpasses sample.
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| CNA2008101370195A CN101373173A (en) | 2008-08-27 | 2008-08-27 | Method and apparatus for testing brittle material strength |
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| CN102818729A (en) * | 2012-09-07 | 2012-12-12 | 广州市建筑材料工业研究所有限公司 | Apparatus and method for detecting flexural bearing capacity of building wallboard |
| CN103608659A (en) * | 2011-06-20 | 2014-02-26 | 空中客车运营简化股份公司 | Device for transversely supporting a longitudinal test tube, and equipment for determining the mechanical bending properties of such a test tube |
| CN104215526A (en) * | 2014-09-24 | 2014-12-17 | 东南大学 | Equi-biaxial bending in-situ loading device based on X-ray computerized tomography and using method |
| CN104316415A (en) * | 2014-10-28 | 2015-01-28 | 中国建材检验认证集团股份有限公司 | Method for testing bending strength of ultra-thin glass |
| CN104949889A (en) * | 2015-06-12 | 2015-09-30 | 郑州磨料磨具磨削研究所有限公司 | Whole flexural testing method and device of ultrathin grinding wheel |
| CN105319129A (en) * | 2014-07-31 | 2016-02-10 | 肖特股份有限公司 | Method and Apparatus for Determining the Fracture Strength of the Margins of Thin Sheets of Brittle-Fracture Material |
| CN105547856A (en) * | 2015-12-21 | 2016-05-04 | 郑州大学 | Concrete material high temperature bending test machine and high temperature bending test method |
| CN107764612A (en) * | 2016-08-18 | 2018-03-06 | 上海宝冶建设工业炉工程技术有限公司 | Inorganic non-metallic material cylindrical specimens prepare mould and preparation method thereof |
| CN109682685A (en) * | 2019-01-07 | 2019-04-26 | 上海建工集团股份有限公司 | Measure the device and method of quasi-brittle material tensile strength |
| CN109827847A (en) * | 2019-02-12 | 2019-05-31 | 合肥炭素有限责任公司 | A kind of graphite electrode nipple flexural strength detection device and its detection method |
| CN110160866A (en) * | 2019-06-20 | 2019-08-23 | 四川大学 | A kind of novel ring-on-ring Biaxial flexturefirings test fixture and its locating cover |
| CN110749514A (en) * | 2019-12-02 | 2020-02-04 | 吉林大学 | Measuring device and measuring method for shear modulus of brittle material |
| CN112067462A (en) * | 2020-09-10 | 2020-12-11 | 中国建材检验认证集团股份有限公司 | Method and device for prefabricating cracks on ultrathin brittle material |
| CN114509336A (en) * | 2021-12-27 | 2022-05-17 | 中国北方发动机研究所(天津) | Adjustable hard brittle material surface stress loading device |
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2008
- 2008-08-27 CN CNA2008101370195A patent/CN101373173A/en active Pending
Cited By (19)
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| CN103608659A (en) * | 2011-06-20 | 2014-02-26 | 空中客车运营简化股份公司 | Device for transversely supporting a longitudinal test tube, and equipment for determining the mechanical bending properties of such a test tube |
| CN103608659B (en) * | 2011-06-20 | 2015-07-29 | 空中客车运营简化股份公司 | The horizontal holding device of longitudinal test piece and determine the equipment of bending machinery feature of this sample |
| CN102818729A (en) * | 2012-09-07 | 2012-12-12 | 广州市建筑材料工业研究所有限公司 | Apparatus and method for detecting flexural bearing capacity of building wallboard |
| CN105319129B (en) * | 2014-07-31 | 2019-03-26 | 肖特股份有限公司 | Method and apparatus for measuring the breaking strength at brittleness-breakable material thin slice edge |
| CN105319129A (en) * | 2014-07-31 | 2016-02-10 | 肖特股份有限公司 | Method and Apparatus for Determining the Fracture Strength of the Margins of Thin Sheets of Brittle-Fracture Material |
| CN104215526A (en) * | 2014-09-24 | 2014-12-17 | 东南大学 | Equi-biaxial bending in-situ loading device based on X-ray computerized tomography and using method |
| CN104316415A (en) * | 2014-10-28 | 2015-01-28 | 中国建材检验认证集团股份有限公司 | Method for testing bending strength of ultra-thin glass |
| CN104949889A (en) * | 2015-06-12 | 2015-09-30 | 郑州磨料磨具磨削研究所有限公司 | Whole flexural testing method and device of ultrathin grinding wheel |
| CN105547856A (en) * | 2015-12-21 | 2016-05-04 | 郑州大学 | Concrete material high temperature bending test machine and high temperature bending test method |
| CN105547856B (en) * | 2015-12-21 | 2018-08-24 | 河南工程学院 | Bend test method in Apparatus for Bending at low-temp and high temperature in concrete material high temperature |
| CN107764612A (en) * | 2016-08-18 | 2018-03-06 | 上海宝冶建设工业炉工程技术有限公司 | Inorganic non-metallic material cylindrical specimens prepare mould and preparation method thereof |
| CN109682685A (en) * | 2019-01-07 | 2019-04-26 | 上海建工集团股份有限公司 | Measure the device and method of quasi-brittle material tensile strength |
| CN109827847A (en) * | 2019-02-12 | 2019-05-31 | 合肥炭素有限责任公司 | A kind of graphite electrode nipple flexural strength detection device and its detection method |
| CN109827847B (en) * | 2019-02-12 | 2022-05-03 | 合肥炭素有限责任公司 | Device and method for detecting breaking strength of graphite electrode joint |
| CN110160866A (en) * | 2019-06-20 | 2019-08-23 | 四川大学 | A kind of novel ring-on-ring Biaxial flexturefirings test fixture and its locating cover |
| CN110160866B (en) * | 2019-06-20 | 2024-02-06 | 四川大学 | Ring-on-ring biax bending strength test fixture and location lid thereof |
| CN110749514A (en) * | 2019-12-02 | 2020-02-04 | 吉林大学 | Measuring device and measuring method for shear modulus of brittle material |
| CN112067462A (en) * | 2020-09-10 | 2020-12-11 | 中国建材检验认证集团股份有限公司 | Method and device for prefabricating cracks on ultrathin brittle material |
| CN114509336A (en) * | 2021-12-27 | 2022-05-17 | 中国北方发动机研究所(天津) | Adjustable hard brittle material surface stress loading device |
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