CN217033365U - Creep testing device and tension-compression creep testing system - Google Patents

Abstract

The utility model provides a creep testing device and a tension-compression creep testing system, wherein the creep testing device at least comprises a device frame, a test piece clamp, a load loading mechanism and a linear displacement sensor, wherein a test piece is arranged in the middle of the test piece clamp, one end of the test piece clamp is a fixed end, the position of the fixed end relative to the device frame is unchanged, and the other end of the test piece clamp is a movable end; the load loading mechanism at least comprises a pulley block and a load. The tension and compression creep testing system provided by the utility model comprises a sealable box body, wherein the box body is provided with a box door, the box body is provided with a constant temperature and humidity device, and the creep testing device provided by the utility model is arranged in the box body. The device can realize long-term automatic acquisition, storage and display of pure tension and pure compression creep of the bamboo/wood-based material in a high-precision controllable climate environment, can realize free switching of tension and compression creep on one set of system through simple transformation and pulley blocks of the test piece clamp, and realizes large-scale miniaturization and light weight of equipment.

Description

Creep testing device and tension-compression creep testing system

Technical Field

The utility model relates to a physical and mechanical property testing device of a bamboo/wood-based material, and relates to a tension-compression creep testing system.

Background

Wood, bamboo or bamboo-wood based materials are the only renewable green materials among the four major building materials, but one of the important indexes for measuring the long-term service performance of the materials-creep performance has been studied by people for more than half a century, but the mechanism of the occurrence and development and the quantitative prediction thereof have great disputes both in academic circles and engineering circles. Especially, the common Creep (Normal Creep) and the Mechanical adsorption Creep (MSC for short) of such materials in the natural service environment (i.e. the environment with temperature and humidity changing) are always the hot and difficult problems of academic research, wherein a test system capable of simulating the natural service environment and automatically measuring, presenting and storing the Creep deformation amount is the key for researching such problems.

In the prior art, creep deformation of wood or bamboo is mostly researched by adopting static bending creep deformation, for example, the applicant filed 'creep deformation testing device, wood creep deformation testing system and testing method' (application number 2020102392173) Chinese utility model patent application in 3/30/2020, which discloses a creep deformation testing device and a testing system aiming at the improved creep deformation testing device, the wood creep deformation testing system provided by the utility model can simultaneously test a certain number of test piece samples in a wood creep deformation test, and the whole system provided by the utility model can continuously and stably detect, record and display general creep deformation of wood, complex wet deformation deflection, dry shrinkage wet swelling capacity and environmental temperature and humidity parameters for a long time, and provides a testing basis and a testing platform for the research of MSC behavior rules and creep deformation mechanisms of wood.

However, the problem that the wood/bamboo material is researched by adopting single static bending creep, which cannot be avoided, is that from the point of view of stress analysis, the static bending creep of the material is actually coupled with the compression creep and the tensile creep of the upper half part of the material. The anisotropic special material properties of the wood and the bamboo cause the mechanical properties of the wood and the bamboo in the stretching, compressing and static bending stress states to be different, for example, the stretching elastic modulus of most of the wood is 1.1-1.2 times of the bending elastic modulus and about 1.1 times of the compression elastic modulus, and more importantly, the basic physical mechanical properties of the wood in the stress direction are not consistent under the influence of temperature and humidity changing environments. Therefore, the study of the creep property of the wood/bamboo material by using single static bending creep tends to cover the special creep rule and property of the wood/bamboo material under the pure tension and pure pressure stress states, and the study method has a larger problem from the scientific research point of view due to the doping of the great difference of the tension, compression, humidity and expansion of the wood/bamboo material and the sensitivity to the environmental temperature and humidity.

At present, the creep performance of bamboo-wood based materials under a stretching/compression mode is still in a primary stage and is limited by an environment temperature and humidity control system and space thereof, most of the current researches are concentrated on a pure test piece creep test under indoor or outdoor conditions, and the researches of the stretching/compression creep under the condition that the environment temperature and humidity can be greatly regulated and controlled are lacked. If the creep test is carried out by using the existing tension/compression instrument, the equipment is expensive, the test method is single, and the test content and the measured data are very tedious and old. Therefore, the prior art lacks a device for tensile/compression mode creep test which can realize automatic acquisition, processing, storage and visual presentation of test creep data, and greatly restricts the depth and development of related research.

SUMMERY OF THE UTILITY MODEL

In order to overcome the defects, the utility model provides a creep testing device and a testing system using the device, which can realize long-term automatic acquisition, storage and display of pure tension and pure compression creep of a bamboo/wood-based material in a high-precision controllable climate environment, the creep testing precision reaches 0.001mm, the precision requirement of wood/bamboo creep testing is completely met, free switching of tension and compression creep can be realized on a set of system through simple transformation of a test piece clamp and a pulley block, and the great miniaturization and light weight of equipment are realized.

The utility model is realized by the following technical scheme:

the creep testing device at least comprises a device frame, a test piece clamp, a load loading mechanism and a linear displacement sensor, wherein the test piece clamp, the load loading mechanism and the linear displacement sensor are all arranged on the device frame, the test piece clamp is used for placing a test piece for creep testing, the test piece is placed in the middle of the test piece clamp, one end of the test piece clamp is a fixed end, the position of the fixed end relative to the device frame is unchanged, and the other end of the test piece clamp is a movable end; the load loading mechanism at least comprises a pulley block and a load, the pulley block is provided with at least one movable pulley and a plurality of fixed pulleys, the load is connected with a movable end on the test piece clamp after penetrating through the pulley block through a steel wire rope, and an acting force is applied to a test piece for creep test through the test piece clamp at the movable end, and the direction of the acting force is on the same straight line with the axial lead of the test piece; the linear displacement sensor collects displacement data of a test piece during creep test.

The device frame comprises a top plate and a bottom plate which are oppositely arranged up and down, and the top plate and the bottom plate are fixedly connected through at least four mutually parallel support rods.

The direction of the acting force applied by the test piece clamp is parallel to the direction of the supporting rod, the load loading mechanism is arranged above the test piece clamp, and a fixed pulley of the load loading mechanism is fixed on the top plate.

Further, the two ends of the test piece clamp are respectively and fixedly provided with the clamp seat plate, the four support rods respectively vertically penetrate through the clamp seat plate, the position of the clamp seat plate located at the fixed end is fixed and unchanged relative to the support rods, and the clamp seat plate located at the moving end can drive the moving end of the test piece clamp to slide along the direction of the support rods, so that tensile or compressive acting force is applied to a test piece on the test piece clamp.

As the tensile creep testing device, a clamp seat plate close to the bottom plate on the test piece clamp can be fixedly connected with the bottom plate to be used as a fixed end, and a clamp seat plate at a movable end is connected with a steel wire rope of the load loading mechanism. When the load passes through the pulley block by the wire rope, an acting force is generated on the moving end, and the clamp seat plate of the moving end is close to the top plate relative to the test piece, so that a tensile acting force is generated on the test piece.

As the compressive creep testing device, a clamp seat plate on the test piece clamp far away from the bottom plate can be fixedly connected with the bottom plate to be used as a fixed end, and a clamp seat plate at a movable end is connected with a steel wire rope of the load loading mechanism. When the load passes through the pulley block through the steel wire rope, acting force is generated on the moving end, and the clamp seat plate of the moving end is close to the bottom plate relative to the test piece, so that compressive acting force is generated on the test piece.

Further, wire rope's end is equipped with the load bedplate parallel with the anchor clamps bedplate, and four spinal branch vaulting poles pass perpendicularly from the load bedplate respectively, load bedplate and bracing piece sliding fit, load bedplate and the anchor clamps bedplate fixed connection that test piece anchor clamps removed the end. The acting force of the pulley block can be uniformly applied to the moving end of the test piece clamp through the load base plate, and the stability and effectiveness of the acting force are guaranteed.

The movable pulley is arranged above the load seat plate and is rotationally connected with the load seat plate. I.e. the load shoe plate corresponds to a part of the movable pulley moving with the movable pulley.

The fixed pulleys are arranged in two numbers, wherein the first fixed pulley is arranged above the movable pulley, the second fixed pulley is arranged on one side, the first fixed pulley and the second fixed pulley are rotatably connected with the top plate, and wheel shafts of the first fixed pulley, the second fixed pulley and the movable pulley are parallel to each other. The first fixed pulley and the movable pulley are arranged up and down, so that the acting force transmitted from the load through the steel wire rope can be ensured to act on the load base plate vertically.

The movable pulley and the first fixed pulley are both three-wheel pulleys, and the second fixed pulley is a single-wheel pulley. The steel wire rope is wound between the movable pulley and the first fixed pulley and finally wound above the second fixed pulley, and the winding modes of the steel wire rope between the movable pulley and the first fixed pulley are two, namely the tail end of the steel wire rope is connected with a hook of the movable pulley or a hook of the first fixed pulley, so that two load acting force amplification ratios of 1:7 or 1:6 can be generated.

Preferably, the tail end of the steel wire rope is connected with the hook of the movable pulley, after the steel wire rope winds three circles between the movable pulley and the first fixed pulley, the steel wire rope is led out from the driven pulley and then winds the second fixed pulley, and the front end of the steel wire rope is vertically connected with the load downwards. This may produce a 1:7 force amplification effect.

The linear displacement sensors are respectively and fixedly connected with the nearest support rod through sensor brackets, and the directions of probes of the linear displacement sensors are opposite; and the middle part of a test piece on the test piece clamp is provided with a pair of bearing platforms, one end of each bearing platform is fixedly connected with the test piece, and the other end of each bearing platform extends to the front of a probe of the linear displacement sensor. The bearing platform is fixed at two ends of the effective section of the test piece, and the test value obtained through the linear displacement sensor is the variable quantity of the effective section of the test piece.

As the tensile creep testing device, the test piece fixture is a pair of tensile clamping seats which are respectively fixed on the fixture seat plate, each tensile clamping seat is provided with an open slot, the open slots of the two tensile clamping seats are opposite, and two ends of the test piece are respectively limited in the open slots of the tensile clamping seats.

The inner walls of the two sides of the open slot are provided with anti-skidding lines which can effectively prevent the displacement of the test piece in the open slot caused by the acting force.

In order to better prevent the test piece from moving in the direction of the acting force in the open slot due to the acting force, the open slot is a dovetail slot.

The inner wall of open slot is smooth, is equipped with the wedge slider between test piece and open slot both sides inner wall, and the side view projection of wedge slider is right trapezoid, and the one side of wedge slider and test piece laminating is vertical face, is equipped with anti-skidding line at vertical face. The vertical face of wedge slider contacts with the test piece and presss from both sides tight test piece, and the both ends of test piece need not to process into the cross sectional shape (trapezoidal) the same with the open slot, can directly process into a pair of planes that are parallel to each other, reduces the processing degree of difficulty of test piece. The anti-slip threads on the vertical surface can prevent the test piece from displacing relative to the wedge-shaped slide block in the direction of the acting force.

And a puller bolt is arranged at the position corresponding to the wedge-shaped sliding block on the bottom of the stretching clamping seat, the puller bolt penetrates through the bottom of the stretching clamping seat and then jacks the bottom of the wedge-shaped sliding block, and the puller bolt is in threaded fit with the stretching clamping seat. The wedge-shaped sliding block is pushed towards the direction of the notch of the open slot through the puller bolt, so that transverse pressure on two sides of the end part of the test piece can be generated, and a better test piece limiting effect is obtained.

And the openings at the two ends of the open slot are respectively provided with a limiting rod, and the two ends of the limiting rod are fixedly connected with the stretching clamping seats. The limiting rod can strengthen the clamping force of the wedge-shaped sliding blocks on two sides of the end part of the test piece and can prevent the wedge-shaped sliding blocks from sliding in the open grooves.

As the compressive creep testing device, the test piece fixture is a pair of pressure plates which are respectively fixed on the fixture seat plate, each pressure plate is provided with a limit groove, the limit grooves of the two pressure plates are opposite, and two ends of the test piece are respectively limited in the limit grooves of the pressure plates. The spacing groove can prevent the displacement of test piece in the non-effort direction.

The tension and compression creep testing system provided by the utility model comprises a sealable box body, wherein the box body is provided with a box door, the box body is provided with a constant temperature and humidity device, and at least one creep testing device provided by the utility model is arranged in the box body.

The frame for fixing the creep testing device is arranged in the box body, at least one creep testing device is arranged on the frame, the top of the device frame of the creep testing device is horizontally fixed at the top of the frame, and the lengths of the top plate and the bottom plate of the device frame are equal to the width of the top of the frame.

The length of the clamp seat plate is equal to that of the load seat plate, and the clamp seat plate and the load seat plate are both smaller than that of the bottom plate; the supporting rods are six, wherein two supporting rods close to one side of the box door are connected with the top plate and the bottom plate, and the other four supporting rods are connected with the top plate and the bottom plate and penetrate through the clamp seat plate and the load seat plate.

The load of the load loading mechanism is arranged on the side close to the box door.

A first fixed pulley and a second fixed pulley of the load loading mechanism are arranged from inside to outside along the center line of the long direction of the top plate, and a movable pulley is positioned under the first fixed pulley; the axial lead and the focus of first fixed pulley, movable pulley, loading bedplate, anchor clamps bedplate, test piece anchor clamps and test piece all are on same vertical line, so can guarantee that the effort can transmit to the test piece effectively.

And a lifting device is arranged right below the load and is placed on the bottom plate.

The lifting device is a jack.

A cushion pad is paved on the bottom plate which is positioned right under the load. The buffer pad is mainly used for preventing the test piece in the test process by the condition of load snap when taking place, the equipment damage that the load dropped the cause.

Drawings

FIG. 1 is a perspective view of a tensile creep test apparatus according to the present invention.

FIG. 2 is a schematic side view of the tensile creep test apparatus of the present invention.

FIG. 3 is a perspective view of the compressive creep test apparatus according to the present invention.

FIG. 4 is a schematic side view of a compressive creep testing apparatus according to the present invention.

FIG. 5 is a schematic view of a specimen holder of the tensile creep test apparatus according to the present invention.

FIG. 6 is a drawing of a tensile clamping base of the tensile creep testing apparatus according to the present invention.

FIG. 7 is a schematic view of a specimen holder of the compressive creep test apparatus according to the present invention.

FIG. 8 is a schematic view of a platen of the compressive creep testing apparatus of the present invention.

FIG. 9 is a schematic view of a fixture seat plate of the creep testing apparatus according to the present invention.

FIG. 10 is a schematic diagram of a creep test system according to the present invention.

FIG. 11 is a schematic diagram of a creep test system case structure according to the present invention.

FIG. 12 is a schematic diagram of a creep test system rack configuration according to the present invention.

FIG. 13 is a diagram of a creep test system chassis in use according to the present invention.

Fig. 14 is a schematic view of a connection structure of the first fixed pulley, the second fixed pulley and the top plate.

Fig. 15 is a schematic view of a connection structure of a movable pulley and a load base plate.

Fig. 16 is a schematic view of the connection structure of the tension clamp seat and the clamp seat plate.

FIG. 17 is a schematic view of a connecting structure of a platen and a clamp seat plate.

Detailed Description

Referring to fig. 1 to 5, the creep test apparatus of the present invention at least includes an apparatus frame 100, a test piece fixture 200, a load loading mechanism 300 and a linear displacement sensor 400, wherein the test piece fixture 200, the load loading mechanism 300 and the linear displacement sensor 400 are all disposed on the apparatus frame 100.

In this embodiment, the assembly frame 100 includes a top plate 110 and a bottom plate 120 disposed opposite to each other, and the top plate 110 and the bottom plate 120 are fixedly connected by at least four support rods 130 parallel to each other.

The test piece fixture 200 is used for placing a test piece 201 for creep test, the test piece 201 is placed in the middle of the test piece fixture 200, one end of the test piece fixture 200 is a fixed end 202, the position of the fixed end 202 relative to the device frame 100 is unchanged, and the other end of the test piece fixture 200 is a movable end 203.

In order to facilitate the connection of the test piece fixture 200 with the device frame 100, two ends of the test piece fixture 200 are respectively and fixedly provided with a fixture seat plate 204, and four support rods 130 respectively vertically pass through the fixture seat plate 204, as shown in fig. 1 and 3, the fixture seat plate 204 is rectangular, and the support rods 130 respectively pass through four corners of the fixture seat plate 204. The position of the clamp seat plate 204 at the fixed end 202 is fixed with respect to the support rod 130, and the clamp seat plate 204 at the movable end 203 can drive the movable end 203 of the test piece clamp 200 to slide along the support rod 130, so as to apply tensile or compressive force to the test piece 201 on the test piece clamp 200.

As long as the powerful effect is held 203 in the removal, just can produce the effort to test piece 201, as to which one end is as which end of stiff end and is regarded as the removal end to and the creep test is tensile creep test or compression creep test, all can be through the removal of restriction wherein one end, and let other end relative motion, according to the direction of motion, alright in order to let same device be suitable for different creep tests.

The acting force is provided by a load loading mechanism 300, the load loading mechanism 300 at least comprises a pulley block and a load 301, the pulley block at least comprises a movable pulley 302 and a plurality of fixed pulleys, the load loading mechanism 300 is arranged above the test piece clamp 200, and the fixed pulleys of the load loading mechanism 300 are fixed on the top plate 110. The load 301 passes through the pulley block through a steel wire rope 303 and then is connected with the moving end 203 on the test piece clamp 201, and exerts an acting force on the test piece 201 of the creep test through the test piece clamp 200 of the moving end 203, the direction of the acting force is on the same straight line with the axial lead of the test piece 201, and the direction of the acting force exerted on the test piece clamp 200 is parallel to the direction of the supporting rod 130, so that the displacement of the moving end 203 can be realized.

As shown in fig. 1 and 2, when it is necessary to perform a tensile creep test, a clamp seat plate 204 of the test piece clamp 200 close to the base plate 120 may be fixedly connected to the base plate 120 as a fixed end 202, and a clamp seat plate 204 of the movable end 203 may be connected to a wire rope 303 of the load applying mechanism 300. When the load 301 passes through the pulley block by the wire rope 303 and then acts on the moving end 203, the clamp seat plate 204 of the moving end 203 is on the side of the top plate 110 relative to the test piece, so when the moving end 203 is pulled, the moving end is pulled towards the top plate 110, and then the load acts on the test piece 201 in a tensile manner.

As shown in fig. 3 and 4, when the compressive creep test is required, the clamp base plate 204 of the test piece clamp 200, which is far from the base plate 120, may be fixedly connected to the base plate 120 as a fixed end 202, and the clamp base plate 204 of the movable end 203 may be connected to the wire rope 303 of the load applying mechanism 300. When the load 301 passes through the pulley block by the wire rope 303 and then acts on the moving end 203, the clamp seat plate 204 of the moving end 203 is on the side close to the bottom plate 120 relative to the test piece, and when the moving end 203 is pulled, the clamp seat plate is still pulled in the direction of the top plate 110, so that a compressive acting force acts on the test piece 201 at this time.

When the tensile test is performed, the clamp seat plate 204 of the fixed end 202 can be directly and fixedly connected with the base plate 120 through a bolt, and the clamp seat plate 204 of the movable end 203 can be directly connected with the steel wire rope 303 to complete the test.

However, in the compression test, the load applying mechanism 300 of the present embodiment cannot generate an urging force in the direction of the bottom plate 120, and only the clamp seat plate 204 on the side close to the top plate 110 is fixed to compress the test piece, and the clamp seat plate 204 close to the bottom plate 120 is pulled to generate a compression urging force. The fixed of anchor clamps bedplate 204, if direct and bracing piece fixed connection, difficult realization because whole device will guarantee in the experimentation that the frictional force between bracing piece and the anchor clamps bedplate is minimum, need to guarantee that the bracing piece surface is smooth, can not just use limit structure or locking structure to destroy the surface of bracing piece 130 because will fix anchor clamps bedplate 204.

In addition, the acting force of the load loading mechanism 300 bypasses the nearest clamp seat plate 204 and is then in transmission connection with the clamp seat plate 204 close to the bottom plate 120, so that it is difficult to ensure that the acting force can be effectively and accurately acted on the test piece 201.

Therefore, in the present embodiment, the end of the wire rope 303 is provided with a load seat plate 304 parallel to the clamp seat plate 204, and the structure of the load seat plate 304 is substantially the same as that of the clamp seat plate 204. The four supporting rods 130 respectively pass through the four corners of the load base plate 304, the load base plate 304 is in sliding fit with the supporting rods 130, and the load base plate 304 is fixedly connected with the clamp base plate 204 of the movable end 203 of the test piece clamp 200 to drive the test piece clamp to move along the supporting rods 130. The acting force of the pulley block can be uniformly applied to the moving end 203 of the test piece clamp 200 through the load base plate 304, and the stability and effectiveness of the acting force are ensured.

In the present embodiment, the clamp base plate 204 is configured as shown in fig. 9, and has through holes 215 for the support rods 130 to pass through near four corners. Four through holes 216 are further formed on the diagonal lines near the corners, and the four through holes 216 are used for bolts to pass through to connect the clamp base plate 204 and the bottom plate 120. The load shoe 304 has the same structure as the clamp shoe 204, and the through holes are identical in location and size.

As shown in fig. 1, the load shoe 304 may be fixedly connected to the nearest fixture shoe 204 during the tensile test. In the compression test, as shown in fig. 3 and 4, the load seat plate 304 is fixedly connected to the clamp seat plate 204 near the bottom plate 120 by a pair of bolts 214 passing through two through holes 216 on the same diagonal, and the clamp seat plate 204 near the load seat plate 304 is fixedly connected to the bottom plate 120 by a pair of bolts 313 passing through two through holes 216 on the other diagonal. The bolt 214 and the bolt 213 need to penetrate through a clamp seat plate except for connecting two components, and the diameter of the through hole 216 should be larger than the diameter of the bolt 214 and the bolt 213 in order not to be obstructed.

The movable pulley 302 in this embodiment is disposed above the load seat plate 304, and the movable pulley 302 is rotatably connected to the load seat plate 304. That is, the load shoe 304 corresponds to a portion of the traveling block 302 moving together with the traveling block 302.

With reference to fig. 1 and 3, there are two fixed pulleys, wherein a first fixed pulley 305 is disposed above the movable pulley 302, a second fixed pulley 306 is disposed at one side, the first fixed pulley 305 and the second fixed pulley 306 are rotatably connected to the top plate 110, and the axle of the first fixed pulley 305, the axle of the second fixed pulley 306 and the axle of the movable pulley 302 are parallel to each other. The first fixed sheave 305 and the movable sheave 302 are vertically provided, and it is ensured that the acting force transmitted from the load 301 through the wire rope 303 is vertically applied to the load seat plate 304.

The movable pulley 302 and the first fixed pulley 305 are both three-wheel pulleys, and the second fixed pulley is 306 a single-wheel pulley. The steel wire rope 303 is wound between the movable pulley 302 and the first fixed pulley 305 and finally wound above the second fixed pulley 306, and the steel wire rope 303 is wound between the movable pulley 302 and the first fixed pulley 305 in two ways, namely, the tail end of the steel wire rope 303 is connected to a hook of the movable pulley 302 or a hook of the first fixed pulley 305, so that two force amplification ratios of the load 301 of 1:7 or 1:6 can be generated.

In this embodiment, the end of the wire rope 303 is first connected to the hook of the movable pulley 302, the wire rope 303 is wound three times between the movable pulley 302 and the first fixed pulley 305, the wire rope is led out from the movable pulley 302 and then wound from the upper surface of the second fixed pulley 306, and the front end of the wire rope 303 is vertically connected to the load 301. This may produce a 1:7 force amplification effect.

The linear displacement sensor 400 collects displacement amount data at the time of creep test of the specimen 201.

Referring to fig. 1, 4, 5 and 7, two linear displacement sensors 400 are provided, and the linear displacement sensors 400 are fixedly connected to the nearest support rod 130 through sensor brackets 401, respectively. Whether the test is a tensile creep test or a compressive creep test, the variation of the effective section of the test piece 201 needs to be tested, so the direction of the probe of each group of linear displacement sensors 400 is opposite.

The middle of the test piece 201 on the test piece clamp 200 is provided with a pair of bearing platforms 402, one end of each bearing platform 402 is fixedly connected with the test piece 201, and the other end of each bearing platform 402 extends to the front of the probe of the linear displacement sensor 400. The bearing platform 402 is fixed at two ends of the effective section of the test piece 201, and the test value obtained by the linear displacement sensor 400 is the variable quantity of the effective section of the test piece 201.

As shown in fig. 5, the tensile creep test apparatus of the present invention includes a pair of tensile holders 205, the tensile holders 205 are respectively fixed on a holder plate 204, and in combination with fig. 6, each tensile holder 205 has an opening groove 206, the opening grooves 206 of the two tensile holders 205 are opposite to each other, and both ends of a test piece 201 are respectively limited in the opening grooves 206 of the tensile holders 205.

The anti-slip patterns 207 can be directly arranged on the inner walls of the two sides of the opening groove 206, and the anti-slip patterns 207 can effectively prevent the test piece 201 from displacing in the opening groove 206 due to acting force.

To better prevent the test piece 201 from moving in the direction of the force in the slot 206 due to the force, the slot 206 is a dovetail slot.

The inner wall of the open slot 206 is smooth, a wedge-shaped sliding block 208 is arranged between the test piece 201 and the inner walls of the two sides of the open slot 206, the side projection of the wedge-shaped sliding block 208 is a right trapezoid, one surface, attached to the test piece 201, of the wedge-shaped sliding block 208 is a vertical surface, and anti-skidding threads 207 are arranged on the vertical surface. The vertical surface of the wedge-shaped sliding block 208 is in contact with the test piece 201 and clamps the test piece 201, the two ends of the test piece 201 do not need to be processed into the section shape (trapezoid) identical to that of the open groove 206, and the two ends can be directly processed into a pair of planes parallel to each other, so that the processing difficulty of the test piece 201 is reduced. The anti-slip thread 207 on the vertical face can prevent the test piece 201 from being displaced relative to the wedge sled 208 in the direction of the force.

A puller bolt 209 is arranged at a position corresponding to the wedge-shaped sliding block 208 on the bottom of the drawing holder 205, the puller bolt 209 penetrates through the bottom of the drawing holder 205 and then is propped against the bottom of the wedge-shaped sliding block 208, and the puller bolt 209 is in threaded fit with the drawing holder 205. The puller bolt 209 pushes the wedge-shaped sliding block 208 towards the notch of the open slot 206, so that the transverse pressure on two sides of the end part of the test piece 201 can be generated, and the effect of limiting the test piece 201 is better.

The openings at the two ends of the open slot 206 are respectively provided with a limit rod 210, and the two ends of the limit rod 210 are fixedly connected with the stretching holder 205. The limiting rod 210 can not only strengthen the clamping force of the wedge-shaped sliding blocks 208 on the two sides of the end part of the test piece 201, but also prevent the wedge-shaped sliding blocks 208 from sliding in the opening grooves 206.

As shown in fig. 7, the test piece holder 200 of the present invention is a pair of holding plates 211, the holding plates 211 are fixed to the holder plate 204, and with reference to fig. 8, each holding plate 211 has a holding groove 212, the holding grooves 212 of the two holding plates 211 are opposite to each other, and both ends of the test piece 201 are held in the holding grooves 212 of the holding plates 211. The limit groove 212 can prevent the specimen 201 from being displaced in the non-force-acting direction.

In this embodiment, the fixed connection between the movable pulley 302 and the load seat plate 304, the fixed pulleys and the top plate 110, and the test piece fixture and the fixture seat plate 204 are all fixed by respectively fixedly arranging a connection column 150, an annular connection groove 151, and a plug pin 152 on the bottom or the housing of each component, as shown in fig. 14 to 17, the connection column 150 is respectively arranged on the first fixed pulley 305 and the second fixed pulley 306, and the annular connection groove 151 is arranged at the corresponding position on the top plate 110; the movable pulley 302 is provided with a connecting column 150, and the load base plate 304 is provided with an annular connecting groove 151 at a corresponding position; the connecting column 150 is arranged on the stretching clamp 205, and the annular connecting groove 151 is arranged on the corresponding position on the clamp seat plate 204; the connecting column 150 is provided on the platen 211, and the annular connecting groove 151 is provided at a corresponding position on the jig base plate 204. After the connecting column 150 of each component is inserted into the annular connecting groove 151, the connecting pin 152 is inserted into the pin holes reserved on the connecting column 150 and the annular connecting groove 151, so that the two components are connected.

In this detachable connection, particularly for the specimen holder 200, the tensile holder 205 and the platen 211 can be replaced easily and quickly, and the specimen holder can be selected and adjusted as desired.

The tension and compression creep testing system provided by the utility model comprises a sealable box body 500, as shown in fig. 10, wherein the box body 500 is provided with a box door 501, the box body 500 is provided with a constant temperature and humidity device, and at least one creep testing device provided by the utility model is arranged in the box body 500.

The box body 500 is internally provided with a rack 502 for fixing a creep test device, the rack 502 is at least provided with one creep test device, the top of the device frame 100 of the creep test device is horizontally fixed at the top of the rack 502, and the lengths of the top plate and the bottom plate of the device frame 100 are equal to the width of the top of the rack 502.

As shown in fig. 12, the frame 502 is a rectangular frame structure, and includes a pair of top beams 506 at the top, four side columns 512, and a pair of bottom beams 505 at the bottom, and a plurality of ribs 513 are further disposed between the side columns 512 at both sides, and are sequentially and equidistantly arranged from top to bottom. The inner walls of the two sides of the box 500 are provided with a plurality of sliding strips 503 at equal intervals from top to bottom, the ribs 513 on the rack 502 are arranged according to the sliding strips 503 in the box 500, the distance between the ribs 513 is equal to the distance between the sliding strips 503, when the rack 502 is pushed into the box 500, the ribs 513 are pushed into the box 500 after corresponding to the sliding strips 503, and the sliding strips 503 are used as sliding rails of the ribs 513 and are also used as the bearing of the whole rack 502.

In practical application, the bottom of the rack 502 does not contact the bottom plate in the box 500, including the creep testing device, and is suspended in the box 500, because the bottom plate in the box 500 is thinner, the rack cannot bear heavy loads. Moreover, the creep testing device is arranged in a suspension manner, so that the climate parameters in the box body 500 are more uniform.

Because the top beam 506 of the frame 502 needs to bear the weight of the whole creep testing device, the top beam 506 can select the circular steel with larger diameter, and the bearing capacity is stronger. Because the frame 502 is a rectangular structure and the creep test needs to be kept natural and vertical, the whole frame 502 cannot be deformed except for ensuring that the top beam 506 is not deformed, and in order to adjust the frame 502, the bottom beams 505 are two rods with variable lengths, and each bottom beam 505 is a rod with two sections connected by threads, so that the length can be adjusted.

Preferably, two connecting beams 504 are further arranged on the inner side of the rack 502 along the diagonal direction, the connecting beams 504 are two sections of threaded rods, and the level of the rack 502 is adjusted by adjusting the length.

All parts of the frame 502 are connected through bolts, and the screw holes are strip-shaped holes, so that the fixing positions of the bolts can be adjusted.

As shown in fig. 13, in the present embodiment, two creep test apparatuses are provided in the box 500, and two creep tests of tension and compression can be performed simultaneously for the same material.

As shown in fig. 1-4, the clamp shoe 204 and the load shoe 304 are equal in length and are both less than the length of the base plate 110; the support rods 130 are six in number, wherein two support rods 130 adjacent to the side of the door 501 connect the top plate 110 and the bottom plate 120, and four other support rods 130 connect the top plate 110 and the bottom plate 120 and pass through the clamp plate 204 and the load plate 304.

The load 301 of the load loading mechanism is provided on the side close to the door 501 so as to control the load applying force.

The first fixed pulley 305 and the second fixed pulley 306 of the load applying mechanism 300 are provided from the inside to the outside along the center line in the longitudinal direction of the top plate 110, and the movable pulley 302 is positioned right below the first fixed pulley 305; the axial lead and the center of gravity of the first fixed pulley 305, the movable pulley 302, the load base plate 304, the clamp base plate 204, the test piece clamp 200 and the test piece 201 are all on the same vertical line, so that the acting force can be effectively transmitted to the test piece.

As shown in fig. 13, a lifting device 507 is provided directly below the load 301, and the lifting device 507 is placed on the base plate 120. The lifting device 507 in this embodiment is a jack, and a scissor jack may be used.

A cushion pad 508 is laid on the bottom plate 120 directly below the load 301. The cushion pad 508 is mainly used to prevent the device from being damaged due to the dropping of the load 301 when the test piece is broken by the load 301 during the test.

The box 500, namely the environmental climate box, in the embodiment is the German BINDER KMF720 environmental climate box, and the linear displacement sensor is the F50-10LVDT displacement sensor of Shenzhen Wolk Intelligent systems Limited. An air inlet system, an air speed adjusting device, a temperature and humidity sensor, a temperature and humidity alarm device, a computer and a power supply of the test system are further arranged in the box body 500 and are arranged outside the box body 500. The wind speed adjusting means includes a hot wire anemometer and a rotational speed regulator. The capability of stably generating, conveying, maintaining and exhausting wet air with specific humidity and temperature in a quantitative, constant-speed and directional manner is formed through the wind speed adjusting device and the temperature and humidity sensor, so that the wood test piece can stably absorb or exhaust gaseous moisture; the humidity, temperature and flow rate of the wet air and the variation range of the humidity, temperature and flow rate are regulated, the control precision of the relative humidity of the wet air is not more than +/-2%, and the control precision of the temperature is not more than +/-0.1 ℃. In practical implementation, in order to prevent the influence of the daily change of the humidity and the temperature of the surrounding environment of the box body on the humidity and the temperature in the box body, particularly the influence of opening the door, and simultaneously to maintain the consistency of the temperature and the humidity of an experimental operation space outside the box body and parameters in the box as much as possible, the experiment can be carried out in the environment with a humidifying/dehumidifying machine and an air conditioner, the adjustable range of the temperature of the surrounding environment of the box body is 10-40 ℃, and the precision is +/-1 ℃; the adjustable range of the relative humidity is 40-80%, and the precision is +/-5%.

The test method utilizing the tension-compression creep test system comprises the following steps:

step 1, selecting a test piece clamp according to a test purpose, mounting a test piece to be tested on the test piece clamp, fixing a clamp seat plate at the fixed end of the test piece clamp, and fixedly connecting a clamp seat plate at the movable end of the test piece clamp with a load seat plate;

step 2, mounting the bearing platform on a test piece, fixing the position of the linear displacement sensor, and respectively butting the probes of the linear displacement sensor against the surface of the bearing platform;

step 3, placing the lifting device on a bottom plate, lifting the load by using the lifting device and connecting the load with a steel wire rope;

step 4, lowering the lifting device until the load is suspended, taking out the lifting device, and paving a cushion pad on the bottom plate below the load;

step 5, closing the box door, starting the constant temperature and humidity device to control the temperature and humidity in the box body, and monitoring data in real time;

and 6, inputting the temperature, humidity and wind speed in the box body and the displacement signal of the test piece acquired in the step 5 into a computer, and storing, processing, analyzing and displaying data.

As shown in fig. 10, the present invention utilizes the transmitter 509 and the data wire 510 to input the collected temperature, humidity, and displacement signals into the computer 511, and then the real-time storage, real-time processing analysis and display of the data can be realized through the programming software programmed based on the VB language. The collected real-time original data are stored in a text format in a database form and used for software real-time data processing and analysis, and meanwhile, the data can be exported at any time and copied as backup, so that the data can be conveniently processed and analyzed offline. Data are obtained by the temperature and humidity sensor, and a real-time coordinate graph with time as a horizontal mark and temperature and relative humidity in the box as vertical marks can be obtained after recording and processing of matched software. After the displacement original data is processed in real time by software, a progressive coordinate graph taking time as a horizontal standard and taking the static bending deflection and the wet expansion and dry shrinkage of a test piece as longitudinal standards is formed for real-time monitoring.

Claims (27)

1. Creep testing arrangement, its characterized in that includes device frame, test piece anchor clamps, load loading mechanism and linear displacement sensor at least, and test piece anchor clamps, load loading mechanism and linear displacement sensor all locate on the device frame, wherein:

the test piece fixture is used for placing a test piece for creep test, the test piece is placed in the middle of the test piece fixture, one end of the test piece fixture is a fixed end, the position of the fixed end relative to the device frame is unchanged, and the other end of the test piece fixture is a movable end;

the load loading mechanism at least comprises a pulley block and a load, the pulley block is provided with at least one movable pulley and a plurality of fixed pulleys, the load is connected with a movable end on the test piece clamp after penetrating through the pulley block through a steel wire rope, and an acting force is applied to a test piece for creep test through the test piece clamp at the movable end, and the direction of the acting force is on the same straight line with the axial lead of the test piece;

the linear displacement sensor collects displacement data during creep test of the test piece.

2. The creep testing apparatus according to claim 1, wherein the apparatus frame comprises a top plate and a bottom plate disposed opposite to each other, and the top plate and the bottom plate are fixedly connected to each other by at least four support rods parallel to each other.

3. The creep test apparatus according to claim 2, wherein the direction of the acting force of the test piece holder is parallel to the direction of the support rod, the load loading mechanism is provided above the test piece holder, and a fixed pulley of the load loading mechanism is fixed to the top plate.

4. The creep testing apparatus according to claim 3, wherein the fixture seat plates are fixed at two ends of the specimen fixture, and four support rods are vertically passed through the fixture seat plates, wherein the fixture seat plate at the fixed end is fixed relative to the support rods, and the fixture seat plate at the movable end is slidable along the support rods.

5. The creep testing apparatus according to claim 4, wherein the clamp base plate of the test piece clamp near the base plate is fixedly connected to the base plate as a fixed end, and the clamp base plate of the movable end is connected to the wire rope of the load loading mechanism.

6. The creep testing apparatus according to claim 4, wherein the clamp base plate of the test piece clamp away from the base plate is fixedly connected to the base plate as a fixed end, and the clamp base plate of the movable end is connected to the wire rope of the load loading mechanism.

7. The creep testing device according to claim 5 or 6, wherein the end of the steel wire rope is provided with a load seat plate parallel to the clamp seat plate, four support rods vertically pass through the load seat plate respectively, the load seat plate is in sliding fit with the support rods, and the load seat plate is fixedly connected with the clamp seat plate at the movable end of the test piece clamp.

8. The creep test apparatus of claim 7 wherein the movable sheave is disposed above the load shoe, the movable sheave being rotatably connected to the load shoe.

9. The creep testing apparatus according to claim 8, wherein there are two fixed pulleys, wherein a first fixed pulley is disposed above the movable pulley, a second fixed pulley is disposed at one side, the first fixed pulley and the second fixed pulley are rotatably connected to the top plate, and the axle shafts of the first fixed pulley, the second fixed pulley and the movable pulley are parallel to each other.

10. The creep testing apparatus of claim 9, wherein the movable sheave and the first fixed sheave are both three-wheeled sheaves, and the second fixed sheave is a single-wheeled sheave.

11. The creep testing device according to claim 10, wherein the end of the wire rope is connected to the hook of the movable pulley, the wire rope is wound three times between the movable pulley and the first fixed pulley, the wire rope is led out from the movable pulley and then wound around the second fixed pulley, and the front end of the wire rope is vertically connected to the load downwards.

12. The creep test apparatus according to claim 3, wherein there are two linear displacement sensors, the linear displacement sensors are respectively fixedly connected to the nearest support rods through sensor brackets, and the directions of the probes of the linear displacement sensors are opposite; and the middle part of a test piece on the test piece clamp is provided with a pair of bearing platforms, one end of each bearing platform is fixedly connected with the test piece, and the other end of each bearing platform extends to the front of a probe of the linear displacement sensor.

13. The creep test apparatus according to claim 5, wherein the specimen holder is a pair of tension holders, the tension holders are respectively fixed on the holder plate, each tension holder has an open slot, the open slots of the two tension holders are opposite, and both ends of the specimen are respectively limited in the open slots of the tension holders.

14. The creep test apparatus according to claim 13, wherein the inner walls of both sides of the open slot are provided with anti-slip threads.

15. The creep testing apparatus of claim 13 wherein the open slots are dovetail slots.

16. The creep testing device according to claim 15, wherein the inner wall of the open slot is smooth, a wedge slider is provided between the test piece and the inner wall of the both sides of the open slot, the side view projection of the wedge slider is a right trapezoid, the surface of the wedge slider attached to the test piece is a vertical surface, and the vertical surface is provided with anti-skid veins.

17. The creep testing apparatus according to claim 16, wherein a tightening bolt is provided on the bottom of the tension holder at a position corresponding to the wedge-shaped slider, the tightening bolt passes through the bottom of the tension holder and then abuts against the bottom of the wedge-shaped slider, and the tightening bolt is in threaded engagement with the tension holder.

18. The creep testing device according to claim 16, wherein a stopper is provided at the opening of the two ends of the open slot, and the two ends of the stopper are fixedly connected to the tension holder.

19. The creep testing apparatus according to claim 6, wherein the test piece holder is a pair of pressing plates, the pressing plates are respectively fixed on the holder plate, each pressing plate is provided with a limiting groove, the limiting grooves of the two pressing plates are opposite, and both ends of the test piece are respectively limited in the limiting grooves of the pressing plates.

20. Tension and compression creep testing system, comprising a sealable box body provided with a box door, the box body being provided with a constant temperature and humidity device, characterized in that at least one creep testing device according to any of claims 1 to 19 is provided in the box body.

21. The tension-compression creep testing system according to claim 20, wherein a rack for fixing the creep testing device is provided in the box, at least one creep testing device is provided on the rack, a top of a rack of the creep testing device is horizontally fixed on a top of the rack, the rack comprises a top plate and a bottom plate which are oppositely provided, the top plate and the bottom plate are fixedly connected through at least four support rods which are parallel to each other, and the lengths of the top plate and the bottom plate of the rack are equal to the width of the top of the rack.

22. The tension-compression creep test system according to claim 21 wherein the clamp seat plate and the load seat plate are equal in length and are each smaller than the length of the base plate; the supporting rods are six, wherein two supporting rods close to one side of the box door are connected with the top plate and the bottom plate, and the other four supporting rods are connected with the top plate and the bottom plate and penetrate through the clamp seat plate and the load seat plate.

23. The tension-compression creep test system according to claim 22, wherein the load of the load loading mechanism is provided on the side close to the door.

24. The tension-compression creep testing system according to claim 23, wherein the first fixed pulley and the second fixed pulley of the load loading mechanism are arranged from inside to outside along the center line of the top plate in the longer direction, and the movable pulley is located right below the first fixed pulley; the axial lead and the gravity center of the first fixed pulley, the movable pulley, the loading seat plate, the clamp seat plate, the test piece clamp and the test piece are all on the same vertical line.

25. The tension-compression creep test system according to claim 24 wherein a lifting device is positioned directly below the load, the lifting device being placed on the base plate.

26. The tension-compression creep test system according to claim 25 wherein the lifting means is a jack.

27. The tension-compression creep test system according to claim 24 wherein a cushion pad is laid on the base plate directly under the load.

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