CN101614636B - Clamp for rail fatigue experiment acted by bending moment - Google Patents
Clamp for rail fatigue experiment acted by bending moment Download PDFInfo
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- CN101614636B CN101614636B CN2009100596108A CN200910059610A CN101614636B CN 101614636 B CN101614636 B CN 101614636B CN 2009100596108 A CN2009100596108 A CN 2009100596108A CN 200910059610 A CN200910059610 A CN 200910059610A CN 101614636 B CN101614636 B CN 101614636B
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Abstract
The invention relates to a clamp for a rail fatigue experiment acted by a bending moment. The upper part of an upper clamp thereof is provided with a threaded rod which is in threaded connection with a force sensor of an experiment machine, the lower part of the upper clamp is provided with a rectangular groove with a downward opening, the flattop part of a triangular loading head is inserted in the rectangular groove, and the upper clamp is connected with the loading head by a screw nail which respectively penetrates through the rectangular groove and the loading head; the lower end of the loading head is in the shape of a camber with the radius of curvature ranging from 1 to 10 mm; and a lower clamp is a rectangular platform, a strip mounting hole which corresponds to a threaded mounting hole of a hydraulic cylinder of the experiment machine is arranged on the lower clamp, a dummy club which is matched with a groove of a connection seat of the hydraulic cylinder of the experiment machine is arranged on the bottom of the lower clamp, both sides of the long edge of the upper surface of the lower clamp are provided with bulges, and threaded holes which are used for fixing samples are arranged on the bulges. The experiment clamp can better simulate the actual working condition of a steel rail in the process of service, and conveniently applies normal load to the steel rail, thereby enabling the rail fatigue experiment acted by the bending moment to be more accurately processed; and the experimental results can provide reliable and effective support for the material selection and the design of the steel rail.
Description
Affiliated technical field:
The invention belongs to the fatigue behaviour experimental technique field of rail material under the moment of flexure effect.
Background technology:
Rail is fixed on the sleeper by railway spike, and rail forms a pair of stiff end contact at per two sections sleeper places.When wheel rolls on rail, inevitably can produce the load of a normal direction to rail, this normal load will make rail constantly be subjected to the effect of moment of flexure.That is to say that normal load will make rail produce downward flexural deformation, i.e. rail lower area tension power effect elongation, the upper area effect of being stressed and contract scarce; At this moment energy dissipation is also different with pure tangential force.Meanwhile, if fatigue crack is on the rail surface or subsurface germinating, the so also effect that will be compressed or stretch, moment of flexure inevitably can exert an influence to the germinating and the expansion of fatigue crack in this case, impel crack Propagation to arrive rail heart portion, and then cause rail fatigue fracture, the operation of locomotive is brought serious potential safety hazard.At present, the high-speed line of China's trial run a large amount of fatigue cracks all occurred as Qun Dynasty's line and Guangzhou-Shenzhen railway.Greatly develop today that track traffic is transported in country, the research and experiment of rail fatigue mechanism and anti-pre-measure, it is more and more important just to seem.The expansion behavior of rail fatigue crackle can be locomotive, wheel track matching Design under the research moment of flexure effect, and rail is selected, installation and maintenance provide necessary useful information and foundation, has great importance for the safe operation of railway.
At present, adopt the standard test criterion for the fatigue experiment of material under the moment of flexure effect, plain clamp carries out.During experiment, the sample two ends are unfixing, therefore have a plurality of degree of freedom, can not simulate the condition of work of rail material in the actual use with moment of flexure effect, selection, design and manufacturing to rail provides reliably, effective foundation thereby experimental result is difficult to.
Summary of the invention:
The purpose of this invention is to provide the clamp for rail fatigue experiment under a kind of moment of flexure effect, use this experiment clip prodigiosin to simulate the rail actual condition in the process under arms enough better, and apply normal load to it easily, carry out the rail fatigue experiment under the moment of flexure effect more accurately, experimental result can provide reliably for the selection and the design of rail, effective foundation.And experiment control and the precision height of testing, the favorable reproducibility of experimental data.
The present invention realizes that the technical scheme that goal of the invention adopts is: the clamp for rail fatigue experiment under a kind of moment of flexure effect, comprise anchor clamps, lower clamp, and its design feature is:
The screw rod of the top of last anchor clamps for being threaded with the experimental machine force transducer, the bottom is the rectangular channel that Open Side Down, inserts the flat top portion of triangle loading head in the rectangular channel; Pass the screw of rectangular channel and loading head, will go up anchor clamps and be connected with loading head; The lower end of loading head is the arc of radius-of-curvature 1～10mm;
Lower clamp is a rectangular platform, lower clamp is provided with and the corresponding rectangular mounting hole of experimental machine hydraulic cylinder threaded mounting hole, the lower clamp bottom is provided with the boss that is complementary with experimental machine hydraulic cylinder Connection Block groove, the both sides, long limit of lower clamp upper surface have projection, and are useful on the fixedly threaded hole of sample on projection.
The using method of experiment anchor clamps of the present invention is: the screw rod that will go up anchor clamps top and the force transducer of experimental machine are by being threaded, and lower clamp bottom boss is inserted in the Connection Block groove of hydraulic cylinder; Again with the sample of the crackle of the prefabricated 0.1～0.2mm in center, by screw retention on the projection at two ends, the lower clamp left and right sides; Mounting screw is passed lower clamp strip mounting hole and be tightened in the hydraulic cylinder mount pad threaded hole, regulate the relative position of lower clamp and hydraulic cylinder again, make the loading head center overlap, tighten mounting screw at last with the sample center.After the installation, start experimental machine, load amplitude, loading speed are set, moving up and down of control hydraulic cylinder applies normal load loading carrying out fatigue experiment to sample.
Compared with prior art, the invention has the beneficial effects as follows:
1, the two ends of sample are fixed on the projection of both sides, long limit of rectangular platform of lower clamp, the actual installation form that is fixed on the sleeper with the rail two ends is identical, thereby have simulated the rail actual condition in the process under arms truly.And apply normal load to it easily by moving up and down of hydraulic cylinder, thus can carry out the fatigue experiment of rail under the moment of flexure effect exactly, experimental result can provide more reliable, effective foundation for the selection and the design of rail.Be fixed the precision height of experiment control and test, the favorable reproducibility of experimental data simultaneously because of loading head, sample two ends.
2, loading head compresses with sample is vertical when test, if the above anchor clamps of loading head connect in vertical mode, then its installation, dismantles extremely difficult.Be connected by the screw side direction between loading head of the present invention and the last anchor clamps, can install, dismantle by the side direction of screw, make loading head pack into, take out, therefore can change loading head very convenient, quickly, make test operation simple more, convenient from the lateral of level.
3, because the replacing loading head is very convenient, therefore can be in each experiment according to the hertz contact theory, calculate the radius-of-curvature of loading head bottom, and change the loading head of corresponding radius-of-curvature, make in maximum contact stress and the rail actual condition in the experiment consistently, have very high relevance between experimental result and the actual condition.Also be that the present invention can realize the realistic simulation to various working by changing the loading head of different sizes.
The present invention is further detailed explanation below in conjunction with the drawings and specific embodiments.
Description of drawings:
Fig. 1 is the main TV structure structural representation of the embodiment of the invention.
Fig. 2 is the side-looking structure structural representation of the embodiment of the invention.
Embodiment:
Embodiment
Fig. 1, Fig. 2 illustrate, and a kind of embodiment of the present invention is: the clamp for rail fatigue experiment under a kind of moment of flexure effect comprises anchor clamps 1, lower clamp 2.The screw rod 11 of the top of last anchor clamps 1 for being threaded with experimental machine force transducer 34, the bottom is the rectangular channel 12 that Open Side Down, insert the flat top portion of triangle loading head 13 in the rectangular channel, pass the screw 14 of rectangular channel 12 and loading head 13, will go up anchor clamps 1 and be connected with loading head 13; The bottom of loading head 13 is the arc of radius-of-curvature 1～10mm.Lower clamp 2 is a rectangular platform, lower clamp 2 is provided with and the corresponding rectangular mounting hole 21 of experimental machine hydraulic cylinder 31 threaded mounting holes, lower clamp 2 bottoms are provided with the boss 23 that is complementary with experimental machine hydraulic cylinder 31 Connection Block grooves 33, the both sides, long limit of lower clamp 2 upper surfaces have projection 24, and are useful on the fixedly threaded hole 25 of sample 4 on projection 24.
The concrete steps of using the experiment anchor clamps of this example to carry out the rail fatigue experiment under the moment of flexure effect are:
The screw rod 11 on last anchor clamps 1 top is threaded with the force transducer 34 of experimental machine, and the boss 23 of lower clamp 2 bottoms is inserted in the Connection Block groove 33 of hydraulic cylinder 31.The sample 4 that has been shaped on crackle in the center in advance is connected by screw 26 on the projection 24 of lower clamp 2 long limits two middle side parts; Mounting screw 28 is passed lower clamp 2 strip mounting holes 21 and be screwed in the hydraulic cylinder mount pad threaded hole, regulate the relative position of lower clamp 2 and hydraulic cylinder 31 again, make loading head 13 centers overlap, tighten mounting screw 28 at last with sample 4 centers.The data acquisition control system of machine is controlled moving up and down of experimental machine hydraulic cylinder 31 and lower clamp 2 by experiment, and makes loading head 13 and sample 4 apply the load amplitude of setting and the loading speed of setting; Collect the load data that the force transducer 34 that links to each other with last anchor clamps 1 is measured by data acquisition control system simultaneously, and hydraulic cylinder 31 displacement data and the cycle index that move up and down, analysis draws at load-displacement curve (F～D curve) of setting under load and the load loading speed condition, to characterize the material deformation process of experimentation.
The experiment anchor clamps that adopt this example have carried out fatigue experiment under the moment of flexure effect to the PD3 rail material.Concrete parameter during experiment is: load amplitude 20～200N, loading speed: 8mm/min.The wide crackle of prefabricated 0.18mm, loading head radius-of-curvature: 1.3mm, size of sample: 220x8x10 (mm).
The experimental result explanation:
1, according to the F～D that notes in the experimentation (load-displacement) curve, the PD3 rail material has all presented typical metal material feature.The 1st cyclic loading～displacement curve of PD3 rail is inc, and this illustrative material plastic yield occurred after the 1st circulation.The 10th cyclic loading～displacement curve closure of PD3 rail illustrates that remaining displacement disappears, and the dissipation that each circulation is produced in the experiment can reduce.The 12000th cyclic loading～displacement curve of PD3 rail becomes stable, illustrates that whole experiment tends towards stability, and the energy of each cycle consumption equates.
2, the crackle macro morphology figure (100 times of sem photographs) behind 12000 circulation experiments can find out that crackle germinates from the precrack top.Behind 12000 circulation experiments crack tip microstructure shape appearance figure as seen, tissue produces a large amount of plastic yield near the crackle, the PD3 rail is to expand in the mode of transgranular fracture all the time.
Claims (1)
1. the clamp for rail fatigue experiment under the moment of flexure effect comprises anchor clamps (1), lower clamp (2), it is characterized in that:
The described screw rod (11) of top of going up anchor clamps (1) for being threaded with experimental machine force transducer (34), the bottom is the rectangular channel that Open Side Down (12), insert the flat top portion of triangle loading head (13) in the rectangular channel (12), pass the screw (14) of rectangular channel (12) and loading head (13), will go up anchor clamps (1) and be connected with loading head (13); The bottom of loading head (13) is the arc of radius-of-curvature 1～10mm;
Described lower clamp (2) is a rectangular platform, lower clamp (2) is provided with and experimental machine hydraulic cylinder (31) the corresponding rectangular mounting hole of threaded mounting hole (21), lower clamp (2) bottom is provided with the boss (23) that is complementary with experimental machine hydraulic cylinder (31) Connection Block groove (33), the both sides, long limit of lower clamp (2) upper surface have projection (24), and are useful on the fixedly threaded hole (25) of sample (4) on projection (24).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009100596108A CN101614636B (en) | 2009-06-16 | 2009-06-16 | Clamp for rail fatigue experiment acted by bending moment |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009100596108A CN101614636B (en) | 2009-06-16 | 2009-06-16 | Clamp for rail fatigue experiment acted by bending moment |
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| Publication Number | Publication Date |
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| CN101614636A CN101614636A (en) | 2009-12-30 |
| CN101614636B true CN101614636B (en) | 2011-08-24 |
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| CN2009100596108A Expired - Fee Related CN101614636B (en) | 2009-06-16 | 2009-06-16 | Clamp for rail fatigue experiment acted by bending moment |
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Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102033025B (en) * | 2010-10-21 | 2012-09-05 | 浙江土工仪器制造有限公司 | Rail fatigue tester |
| CN104458437A (en) * | 2013-09-17 | 2015-03-25 | 珠海格力电器股份有限公司 | Test device for testing bending resistance and stress resistance of electronic component |
| CN105547837B (en) * | 2016-01-29 | 2018-02-16 | 中国石油大学(华东) | A kind of soldered fitting fracture toughness test device |
| CN106226166A (en) * | 2016-07-14 | 2016-12-14 | 上海核工程研究设计院 | A kind of fatigue test method measuring antifreeze plate service life |
| CN107796693A (en) * | 2017-09-29 | 2018-03-13 | 清华大学 | A kind of three point bending test device and method |
| CN108982241B (en) * | 2018-06-13 | 2021-02-19 | 重庆工业职业技术学院 | Metal material bending test device |
| CN109507050B (en) * | 2019-01-02 | 2021-11-02 | 攀钢集团攀枝花钢铁研究院有限公司 | Rail joint head eccentric loading-rail web fatigue test device and method |
| CN110455653A (en) * | 2019-07-24 | 2019-11-15 | 上海唯万密封科技有限公司 | A kind of strength test technique of skeleton structure nonmetallic materials |
| CN110987680A (en) * | 2019-12-13 | 2020-04-10 | 华中科技大学 | Bending strain generating device and application thereof |
| CN112378761B (en) * | 2020-09-30 | 2023-10-24 | 华东交通大学 | Data detection test bed for railway steel rail and use method thereof |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101178345A (en) * | 2007-12-05 | 2008-05-14 | 西南交通大学 | Twisting or micro-moving frictional wear test method and device thereof |
| CN201429547Y (en) * | 2009-06-16 | 2010-03-24 | 西南交通大学 | High speed railway steel rail bending fatigue performance test clamp |
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2009
- 2009-06-16 CN CN2009100596108A patent/CN101614636B/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101178345A (en) * | 2007-12-05 | 2008-05-14 | 西南交通大学 | Twisting or micro-moving frictional wear test method and device thereof |
| CN201429547Y (en) * | 2009-06-16 | 2010-03-24 | 西南交通大学 | High speed railway steel rail bending fatigue performance test clamp |
Non-Patent Citations (1)
| Title |
|---|
| 胡家杰等.弯矩作用下钢轨疲劳裂纹扩展行为研究.《铁道工程学报》.2008,(第9（2008年）期),第27页左栏第20行至右栏第9行，附图1-2. * |
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| CN101614636A (en) | 2009-12-30 |
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