CN102121885B - Hydraulic support body for direct tensile test device - Google Patents

Abstract

The invention relates to a hydraulic support body for a direct tensile test device. A tensile device is formed by laminating a group of cylindrical components with a common central axis, and comprises an upper end cap, a lower end cap, an upper chain, a lower chain, an upper joint and a lower joint, wherein the upper and lower end caps fix a sample; the upper and lower chains are connected with the upper and lower end caps respectively; the upper and lower joints are connected with the other end of each of the upper and lower chains respectively; and the lower joint is fixed on a tester base. The support body consists of a hydraulic cylinder with liquid, and is divided into a support tube and a measurement tube which are communicated by a hollow conduit. In a testing process, numerical values of a buoyancy force provided by a hydraulic pressure can be calculated by measuring height differences of changes of a liquid level in the measurement tube, and are removed from tensile data to reduce system errors. Moreover, in the support body, the hydraulic pressure replaces the elasticity of a conventional spring so as to widen the measurement data of test data, achieve higher convenience of operation, improve the measurement accuracy and effectively timely prevent the test device from being damaged when accidents happen in a tensile test.

Description

A kind of direct tensile test device that supports through hydraulic pressure

Technical field

The present invention relates to the direct tensile test device of hard brittle material, relate in particular to a kind of direct tensile test device that supports through hydraulic pressure.

Background technology

Nowadays the direct tensile test device is widely used in the tensile mechanical property testing of hard brittle material such as rock, and obviously, test unit is very big to the accuracy influence of determination data, and the sample support body is considered to parts very crucial in the test unit.Hard brittle material, is especially had higher requirement to the sample support body to test unit owing to its special resistance to compression and tension character.The general rigid sleeve that uses is done supporter in traditional test unit; But rigid sleeve has individual defective; When sample is stressed when reaching peak value, under the sample below the destruction face, lower endcaps and the suffered action of gravity of bottom chain, sample takes place to destroy suddenly; Test stops, and can not effectively carry out the mensuration of tensile mechanical character behind the peak.In order to address this problem; One Chinese patent application number is that 200610022224.8 to disclose a kind of technical scheme be that rigid sleeve is substituted (annex is shown in Figure 1) by support spring 8; Like this in whole tension test; Support the weight of sample 5 and other test component by spring 8, can accomplish the mensuration of overall process curve basically.Yet, after rigid support changes resiliency supported into, will cause new problem.As shown in the figure, before on-test, must make spring generation compression deformation, then mounting spring and lower member thereof (otherwise after on-test, spring will separate with lower endcaps, become the same with rigid support, not have effective supporting).The counter-force that camber of spring provides gets in the data acquisition storehouse through the sensor that is connected in lower clamp.After on-test, sample deforms, and chain can produce certain elongation in the preceding bottom of peak value, and the compression deformation of spring is shunk, and the counter-force that provides is corresponding to be reduced; The elongation of peak value rear lower chain reduces, and the compression deformation of spring strengthens, the corresponding increase of the counter-force that provides, and the counter-force that spring changes gets in the data acquisition storehouse through sensor.This shows that the counter-force that elastic support provides is not a certain value in entire test, when this gives last deal with data, reject this counter-force and reduce systematic error and brought very big difficulty.Because tensile strength of fragile material is low, the fail in tension load is little, so because the systematic error that the spring counter-force produces influence also seems very serious, especially more obvious in the test behind the peak.So this elastic support has had a strong impact on the precision of test figure.In addition, this spring support also can bring following new problems: 1) sample destroys in the end.Sample should destroy in the middle part in theory; But, from the whole process of tension test, in drawing process; Spring and chain can produce double swerve and influence test figure; What especially become in the test near peak stress and behind the peak is more outstanding, causes sample to destroy in the end, does not really reflect the mechanical property of hard brittle material in the stretching overall process; 2) bad adaptability.For the specimen size of direct tensile test, standard is not done relevant provisions, so volume of sample, weight, tensile strength etc. can differ greatly; Therefore the anchorage force to supporter also has different requirement, like the sample that small size is broken easily, just should not use the excessive spring of the coefficient of stiffiness; Otherwise there is not difference with rigid support, otherwise, the sample that big volume is not easy to break; Also should not use the too small spring of the coefficient of stiffiness, otherwise spring is just ineffective.Therefore to prepare a lot of springs according to different tests, when continuously various sample being done tension test, also will constantly change spring, increase the complicacy of operation; 3) installation procedure is complicated.Shown in Figure 1 like annex, from process of the test, when after single test finishes, testing, take down upper and lower cotter joint next time, change test specimen, upper and lower cotter joint is installed then.As can be seen from the figure, lower sub, following latch and chain are all wrapped up by spring, and the spring inner narrow space, the distance between two rings is also very little, brings a lot of inconvenience for the installation of lower member; 4) spring can deform and wear out in long-term use, influences the normal performance of its performance.Based on above reason, be necessary to seek a kind of supporter that overcomes the tensile test apparatus of these defectives of spring, this adverse effect is rejected.

Summary of the invention

The objective of the invention is provides a kind of hydraulic support body of direct tensile test device in order to overcome the defective of tensile test apparatus elastic support in the prior art.It comprises: the upper end cap 3 of fixing sample 5 and lower endcaps 6, connect the last chain 2 and the lower chain 9 of two end caps up and down respectively, and with top connection 1 and lower sub 10 that the last lower chain other end links to each other respectively, lower sub is fixed on the tester base 11; Upper end cap 3 and lower endcaps 6, last chain 2 and lower chain 9, top connection 1 and lower sub 10 have common vertical axis and are the layered laminate arrangement.Wherein between lower endcaps and tester base, be provided with the sample support device; Described sample support device is made up of a hydraulic pressure cylinder assembly; This hydraulic pressure cylinder assembly comprises that the support tube that can keep hydraulic cylinder buoyancy 18, one can measure measurement tube 16, this support tube 18 of hydraulic cylinder buoyancy and measure in the tube 16 liquid 17 that will produce buoyancy is arranged; Support tube 18 has hollow tubing conductor to be communicated with measuring between tube 16 bottoms; Have in the support tube 18 in back up pad 12, the measurement tube 16 the check weighing plate 13 that can measure hydraulic floatage is arranged, the outstanding weight 15 that is used to measure hydraulic floatage of rope is arranged at check weighing plate 13 tops; When tension test is carried out; The samples 5 of lower endcaps 6 and top thereof etc. receive from the liquid buoyancy in the support tube 18 through back up pad 12 and keep balance; Wherein back up pad 12 is close to support tube 18 barrels, and liquid 17 is loaded into buoyancy on the back up pad 12 of top in the sealing support tube 18.Sample deforms in the process of the test, and before peak value, certain elongation also takes place last lower chain thereupon, and back up pad 12 and supporting pad 14 also move up thereupon, and support tube 18 liquid levels rise, and measures tube 16 liquid levels and descends; The elongation strain of lower chain produces certain shrink behind the peak value, and back up pad 12 and supporting pad 14 also move down thereupon, and support tube 18 liquid levels descend, and measures tube 16 liquid levels and rises.In entire test; Record is axial tension the time, can write down support tube 18 and measure the delta data of the liquid level of tube 16 with sensor, in the end during the Processing Test data;, back up pad 12 poor and check weighing plate 13 contact liq surface areas, weight 15 weight through liquid level; Just can calculate the numerical value that hydraulic pressure provides buoyancy, and it is removed from the stretching data, reduce systematic error.

In the above-mentioned technical scheme, the described lower chain of going up reaches latch 7 down, the dismounting that so also can conveniently go up lower chain with the last latch that is respectively equipped with anti-chain releasing up and down between the end cap 4.

In the above-mentioned technical scheme, between described back up pad 12 and the lower endcaps 6 supporting pad 14 is arranged, can adopt indeformable rigid material, lower endcaps 6 is fully contacted with supporting pad 14.

In the above-mentioned technical scheme, there is the cylindrical sleeve of a smooth outer surface described lower chain 9 outsides, and are porose on the back up pad 12, and back up pad can be done on this cylindrical sleeve outer wall just and slide up and down, and prevents that liquid 17 from spilling.

In the above-mentioned technical scheme, described measurement tube 16 usefulness transparent materials are processed, and axial scale mark is arranged on the barrel; Can measure the variation of this interior liquid level; This scale mark direction promptly is vertical shape along the parallel direction of measuring tube 16 walls in test unit, vertical with liquid level.

In the above-mentioned technical scheme, described scale mark also can be a moving scale device, when tension test begins, can carry out the correction of zero graduation value, makes the zero graduation mark and measure tube 16 interior liquid levels identical through regulating the graduator position.So just can directly read the changing value of liquid level, needn't write down liquid level initial value and calculating, can eliminate the personal error in the reading effectively.

In the above-mentioned technical scheme; On the moving scale chi handle 20 of described moving scale device movable vernier is arranged; In process of the test, can move freely; Can accurately read the height value of measuring liquid level in the tube 16 like this, vernier was positioned at the zero graduation place of handle 20 when tension test began, and can move up and down along handle (20) with check weighing plate (13).

In the above-mentioned technical scheme, snubber assembly is arranged in the hydraulic cylinder, comprise the cushion pad of lower chain 9 bottoms and the liquid overflow pipe on measurement tube 16 tops.When unscheduled event took place, impulse force was excessive during like sample 5 fracture when exceeding the scope of design that this test unit bears, and cushion pad can effectively be prevented and treated lower endcaps 6 and promote that check weighing plates 13 are fierce to impact lower subs 10, also can cause to measure tube 16 liquid levels and surpass the barrel height.Liquid overflow pipe can make when liquid level surpasses measurement range in measuring tube 16, and liquid 17 can flow to outside the hydraulic cylinder through liquid overflow pipe, prevents that check weighing plate 13 is rushed out measurement tube 16.

The present invention has obtained following technique effect:

1, in tension test; Supporter replaces spring with hydraulic part, can overcome many defectives of spring, and is yielding like spring long back service time; To change the spring of the corresponding coefficient of stiffiness according to the various sample part; Spring is in the unexpected easy vibrations in back etc. of pressurizeing, and these all are unfavorable for the accurate measurement of data, also can cause other problem.Adopt hydraulic support body, just can address these problems;

2, measuring the movable vernier that automatic correct zero scale position is arranged on the tube and write down the liquid level lifting position automatically, can realize the robotization of tension test, intelligent degree, alleviate the hand labor intensity in the test, and effectively improve the degree of accuracy of determination data;

3, the weight of measuring buoyancy in will testing replaces with spring, just needn't change for the different a large amount of weights of sample preparation, has expanded the measurement range of test figure greatly, can be fit to the sample of all kinds of different tensile strength is tested;

4, in the hydraulic cylinder buffer protection device is arranged, can make test meet accident or test when going beyond the scope and effective protection is provided test unit.

Figure of description

Fig. 1 is a direct tensile test apparatus structure synoptic diagram of the prior art;

Fig. 2 is for there being the stretching device structural representation of hydraulic support body in the direct tensile test of the present invention;

Fig. 3 is the back up pad member stereographic map (amplifying) among the present invention;

Fig. 4 is the vertical view of Fig. 3;

Fig. 5 is the supporting pad stereographic map (amplifying) among the present invention;

Fig. 6 is the vertical view of Fig. 5;

Fig. 7 is the hydraulic cylinder vertical view (amplifying) among the present invention;

Fig. 8 is the measurement tube moving scale device structural representation (amplifying) among the present invention.

Mark among the figure: latch, 8_ support spring, 9_ lower chain, 10_ lower sub, 11_ tester base, 12_ back up pad, 13_ check weighing plate, 14_ supporting pad, 15_ weight, 16_ measure tube, 17_ liquid, 18_ support tube, 19_ moving scale chi floating plate, 20_ moving scale chi scale handle, 21_ moving scale chi locking folder under 1_ top connection, the last chain of 2_, 3_ upper end cap, the last latch of 4_, 5_ sample, 6_ lower endcaps, the 7_.

Embodiment

Understand and embodiment of the present invention for the ease of those of ordinary skills, the present invention is made further detailed description below in conjunction with accompanying drawing and embodiment.

Fig. 2 is the test unit among the present invention, is divided into stretching device and supporter two large divisions.

Above-mentioned stretching device has the cylindrical element of common center axis to cascade by one group; Comprise: the upper end cap 3 of fixing sample 5 and lower endcaps 6; Connect the last chain 2 and the lower chain 9 of two end caps up and down respectively; With top connection 1 and lower sub 10 that the last lower chain other end links to each other respectively, lower sub is fixed on the tester base 11; Last lower chain and be respectively equipped with the last latch 4 and time latch 7 of anti-chain releasing up and down between the end cap.

Aforesaid supporter by one liquid 17 is housed hydraulic cylinder form; Hydraulic cylinder divides two parts (see figure 7); Support tube 18 and measurement tube 16; Have hollow tubing conductor to be communicated with between these two tube bottoms, promptly the hollow tubing conductor between support tube, hydraulic measurement tube and the bottom thereof constitutes U-shaped communicating pipe, and liquid 17 can be flowed freely between two tubes.In the back up pad 12 of reliable hydraulic floatage, the measurement tube 16 the check weighing plate 13 that can measure hydraulic floatage is arranged in the support tube 18 wherein; The back up pad 12 here and the density of check weighing plate 13 are all less than liquid 17 density; Therefore float on liquid 17 surfaces; Smooth and be close to smooth separately barrel around it, play the effect of seal fluid 17, and along with the fluctuation of liquid in the tube separately can slide up and down.

Can also improve as follows supporter:

1) between above-mentioned back up pad 12 and the lower endcaps 6 lightweight supporting pad 14 is arranged, can adopt indeformable rigid material, lower endcaps 6 is fully contacted with supporting pad 14;

2) there is the cylindrical sleeve of a smooth outer surface above-mentioned lower chain 9 outsides; Porose on the back up pad 12; Cylindrical sleeve is passed this hole just, back up pad 12 is done on this cylindrical sleeve outer wall slided up and down, and the inwall in hole also is smooth; And be close to the cylindrical sleeve surface, when sliding, can prevent that liquid 17 from spilling.

Embodiment:

In tension test, with upper end cap 3 and lower endcaps 6 also tensions of fixing sample 5, liquid level in the regulator solution cylinder pressure (can or extract liquid out and realize) from 16 injections of measurement tube; Supporting pad 14 is contacted with lower endcaps 6, and adopt the check weighing plate 13 bigger than supporting pad 14 density of material, or other weight that on check weighing plate 13, superposes; Make hydraulic cylinder internal buoyancy balance; Liquid level is identical in support tube 18 and the measurement tube 16, otherwise two initial liquid levels of tube are different, influence follow-up test.Above check weighing plate 13,, weight 15 is contacted with check weighing plate 13, but check weighing plate 13 does not bear the weight of weight 15 with tightrope suspension weight 15.

Install device, before on-test, write down following data:

1) useful area of back up pad 12 contact liqs 17;

2) useful area of check weighing plate 13 contact liqs 17;

3) density of liquid 17;

4) measure liquid level value, the i.e. height of check weighing plate 13 bottoms in the tube 16;

5) weight 15 weight;

6) lower endcaps 6 weight.

After on-test, sample deforms, before peak value on lower chain certain elongation also takes place thereupon, back up pad 12 and supporting pad 14 also move up thereupon, support tube 18 liquid levels rise, and measure tube 16 liquid levels and descend; The elongation strain of lower chain produces certain shrink behind the peak value, and back up pad 12 and supporting pad 14 also move down thereupon, and support tube 18 liquid levels descend, and measures tube 16 liquid levels and rises.In entire test, in the time of the record axial tension, write down the delta data of the liquid level of support tube 18 and measurement tube 16 with sensor.When off-test aftertreatment data, the weight of, back up pad 12 poor through liquid level and check weighing plate 13 contact liq surface areas, weight 15 just can calculate the numerical value that hydraulic pressure provides buoyancy, and it is removed from the stretching data, reduces systematic error.

In order further to improve the intellectuality and the automaticity of data acquisition in the above-mentioned tension test, alleviate the hand labor intensity in the test, can improve as follows measuring tube 16:

Improvement project 1:

Measuring on the tube 16 has axial scale mark, measures tube 16 and can adopt transparent material, and scale mark is engraved on the barrel, similar common liquid graduated cylinder, the directly variation of liquid level in this tube of may observe.

Improvement project 2:

Above-mentioned scale mark can be designed to a moving scale device, as be enclosed within measure barrel one movable ruler, when tension test begins, can carry out the correction of zero graduation value; Regulate the graduator position through sliding up and down; Liquid level is identical in making the zero graduation mark and measuring tube 16, the measurement during like this applicable to the arbitrary height liquid level, and the scale on the graduator that liquid level arrives is exactly actual level change height; Needn't calculate, directly reading of data.

Improvement project 3:

On the above-mentioned handle that the moving scale line is arranged 20 movable vernier is arranged, can move freely in the process of the test.Vernier was positioned at the zero graduation place of handle 20 when tension test began; After on-test, movable vernier and check weighing plate 13 fix, and then check weighing plate 13 can spur vernier and moves along handle 20, demonstrates the height of level change.

Improvement project 4:

In tension test, sometimes because of misoperation or because the reason of test specimen itself possibly cause its unexpected fracture.If the impulse force in when fracture is excessive when exceeding the scope of design that this test unit bears, lower endcaps 6 can promote that back up pads 12 are fierce impacts lower subs 10, causes the damage of relevant parts; Also may cause in addition and measure tube 16 liquid levels, check weighing plate 13 gone out measured tube 16, and liquid 17 is spilt outside the hydraulic cylinder, the impact mitigation measure that therefore will be necessary above the barrel height.

For addressing the above problem, be designed with 2 snubber assemblys in the hydraulic cylinder, comprising:

1) cushion pad of lower chain 9 bottoms, cushion pad can alleviate the impact to lower sub 10, prevents that relevant stressed member from damaging,

2) liquid overflow pipe on measurement tube 16 tops, when liquid level surpassed measurement range in measuring tube 16, liquid 17 can flow to outside the hydraulic cylinder through liquid overflow pipe, prevented that check weighing plate 13 is rushed out measurement tube 16.

Above content is to combine concrete preferred implementation to the further explain that the present invention did, and can not assert that practical implementation of the present invention is confined to these explanations.For the those of ordinary skill of technical field under the present invention, under the prerequisite that does not break away from the present invention's design, can also make some simple deduction or replace, all should be regarded as belonging to protection scope of the present invention.

Claims (1)

1. one kind is passed through the direct tensile test device that hydraulic pressure supports; It comprises: the upper end cap (3) of fixing sample (5) and lower endcaps (6); Connect the last chain (2) and the lower chain (9) of two end caps up and down respectively; With top connection (1) and lower sub (10) that the last lower chain other end links to each other respectively, lower sub is fixed on the tester base (11); Upper end cap (3) and lower endcaps (6), last chain (2) and lower chain (9), top connection (1) and lower sub (10) have common vertical axis and are the layered laminate arrangement; It is characterized in that: be provided with the sample support device between lower endcaps and the tester base; Described sample support device is made up of a hydraulic pressure cylinder assembly; This hydraulic pressure cylinder assembly comprises that a support tube (18), one measure the measurement tube (16) of hydraulic cylinder buoyancy, this support tube (18) and measure in the tube (16) liquid (17) is arranged, and support tube (18) has between tube (16) bottom that hollow tubing conductor is communicated with, back up pad (12) is arranged in the support tube (18), measures and have check weighing plate (13), check weighing plate (13) top that can measure hydraulic floatage that the weight that is used to measure hydraulic floatage (15) of restricting and hanging is arranged in the tube (16) with measuring; When tension test is carried out; The sample (5) of lower endcaps (6) and top thereof receives from the liquid buoyancy in the support tube (18) through back up pad (12) and keeps balance; Wherein back up pad (12) is close to support tube (18) barrel, and the sealing interior liquid of support tube (18) (17) is loaded into buoyancy on the back up pad (12) of top.

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