CN108760496B - Involute type flexible material multiaxial tensile testing machine - Google Patents
Involute type flexible material multiaxial tensile testing machine Download PDFInfo
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- CN108760496B CN108760496B CN201810551749.3A CN201810551749A CN108760496B CN 108760496 B CN108760496 B CN 108760496B CN 201810551749 A CN201810551749 A CN 201810551749A CN 108760496 B CN108760496 B CN 108760496B
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- 239000000463 material Substances 0.000 title claims abstract description 52
- 238000009864 tensile test Methods 0.000 title claims abstract description 29
- 230000007246 mechanism Effects 0.000 claims abstract description 11
- 238000000034 method Methods 0.000 claims description 18
- 230000033001 locomotion Effects 0.000 abstract description 15
- 238000010586 diagram Methods 0.000 description 19
- 230000008569 process Effects 0.000 description 14
- 238000005259 measurement Methods 0.000 description 8
- 229920001971 elastomer Polymers 0.000 description 7
- 238000002474 experimental method Methods 0.000 description 7
- 239000000806 elastomer Substances 0.000 description 6
- 238000004364 calculation method Methods 0.000 description 3
- 125000004122 cyclic group Chemical group 0.000 description 3
- 238000009661 fatigue test Methods 0.000 description 3
- 230000001360 synchronised effect Effects 0.000 description 3
- 239000007769 metal material Substances 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
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- 238000006467 substitution reaction Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/02—Details
- G01N3/04—Chucks
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0014—Type of force applied
- G01N2203/0016—Tensile or compressive
- G01N2203/0017—Tensile
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0058—Kind of property studied
- G01N2203/0069—Fatigue, creep, strain-stress relations or elastic constants
- G01N2203/0075—Strain-stress relations or elastic constants
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/04—Chucks, fixtures, jaws, holders or anvils
- G01N2203/0423—Chucks, fixtures, jaws, holders or anvils using screws
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/06—Indicating or recording means; Sensing means
- G01N2203/0641—Indicating or recording means; Sensing means using optical, X-ray, ultraviolet, infrared or similar detectors
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- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
Abstract
The invention discloses an involute type flexible material multi-axis tensile testing machine, which comprises a machine body and a tensile mechanism arranged on the machine body; the stretching mechanism comprises a lower disc, an upper disc, a clamp and a connecting rod; the upper disc and the lower disc are coaxially arranged, the lower disc is fixedly connected with the machine body, the upper disc is rotationally connected with the machine body, a boss is arranged at the center of the upper disc, a plurality of clamps are annularly arranged on the upper disc around the center of the boss, involute guide grooves corresponding to each clamp are formed in the upper disc, a linear guide groove corresponding to each involute guide groove is formed in the lower disc, a connecting rod sequentially penetrates through the corresponding linear guide groove and the involute guide groove to be rotationally connected with each clamp, and the connecting rod can slide in the corresponding linear guide groove and involute guide groove. The involute guide groove is matched with the corresponding straight guide groove to push the clamp to reciprocate along the straight guide groove, and the thrust pressure angle to the clamp is 0, so that the friction force in the motion of the mechanism is minimum, and the synchronism and the equality of the pulling force are ensured.
Description
Technical Field
The invention relates to the technical field of tensile test equipment, in particular to an involute type flexible material multi-axis tensile testing machine.
Background
The mechanical properties of a material generally refer to the state of deformation of the material under a force, or the effect of a force exerted by the material under a given deformation condition. The mechanical properties of the materials are studied, and sometimes multidirectional forces are required to be applied to the material sample to observe the deformation of the material sample under the action of multi-axis forces.
An ideal multi-axis tensile testing machine has the following characteristics:
1. can synchronously apply multidirectional force; 2. ensuring that the measured sample is uniformly stretched; 3. the tensile force in all directions can be accurately measured; 4. the deformation condition of the sample can be synchronously measured in the stretching process; 5. and the clamping of the material sample is convenient. The most common biaxial tensile testing machine is a cross-shaped material and other biaxial tensile testing machine, and the basic working principle of the mechanical part of the biaxial tensile testing machine is that a stepping motor is used for driving a ball screw to rotate to drive a sliding block to move on a linear guide rail, so that tensile force on a sample is generated, 4 or 2 groups of linear guide rails are vertically distributed in a cross shape, and the observation of the deformation condition of the sample is generally realized by adopting a camera suspended above a stretching platform.
According to the related patent search, the existing biaxial stretching experimental equipment of the material adopts a cross biaxial stretching mode, and the specific equipment comprises two types, namely, a hydraulic actuation mode is adopted for loading a metal material with modulus more than 1GPa and small deformation, and the generated tensile force is generally more than 5 kN; the other is to the film material with modulus less than 1MPa, the structure is generally formed by installing two guide rails in mutually perpendicular directions, and driving a screw rod to rotate by a motor to drive a clamp on the guide rails to move.
The problems with the first type of device are:
1. the measurement accuracy is low. Because of the complex structure of the driving and controlling device, the measuring range of the load sensor is larger, and the accuracy of the force value measuring result is lower when the flexible material with smaller modulus or other elastic materials with smaller modulus are measured.
2. The measurement range is limited. Because of the adoption of the cross-shaped tensile test sample, the area of the test sample surface in effective equibiaxial deformation is small, and the test sample surface cannot be used for measuring the large deformation state of flexible materials or other elastomer materials.
3. The large deformation cannot be accurately measured. Because the biaxial tensile testing machine for metal materials usually adopts a mode of attaching strain gages to measure deformation, the strain gages are limited by the use conditions of the strain gages, and the measurement of large strain can not be performed.
The use of the second apparatus can be used for equibiaxial tensile testing of flexible materials or other elastomeric materials of lesser modulus, but suffers from several drawbacks:
1. the synchronicity and equality of the two shaft tensions is not easily controlled. Because the experimental device needs two stepper motors to drive simultaneously, the requirements on the synchronism and start-stop control precision of the two driving motors are very high, if the two motors are not synchronous, the stretching forces of the two shafts are different, and further the deformation of a material sample in the stretching process is uneven, and the condition of equibiaxial deformation cannot be met. The accuracy of most stepping motors can not really meet the control requirement of synchronism;
2. the measurement range is limited. Because of the adoption of the cross-shaped tensile sample, the area of the surface of the sample, which is in effective equibiaxial deformation in the tensile process, is smaller, and the measurable maximum deformation range is limited by the lengths of the guide rail and the screw rod.
3. The method can only be used for carrying out steady-state or quasi-static equibiaxial stretching experiments of material samples, and cannot be used for cyclic stretching fatigue tests of the samples. Because the mechanical clearance of the screw transmission mode is large, the mechanical execution efficiency is low, the dynamic response performance is poor, and the clamp cannot be driven to perform high-speed reciprocating motion, so that the equipment cannot be used for a cyclic tensile fatigue test.
4. The flexible material or other high elastomer material has special physical properties, and the stress-strain curve obtained by only one stretching is insufficient to describe the complete stretching mechanical property of the high elastomer, so that the current metal equibiaxial stretching experiment machine does not have an effective experiment method and a data processing method aiming at the high elastomer.
5. The sample is difficult to clamp, and the material is easy to be separated or broken in the stretching process.
Disclosure of Invention
The invention aims to provide an involute type multi-axis tensile testing machine for flexible materials, which aims to solve the technical problems in the prior art.
The invention provides an involute type flexible material multi-axis tensile testing machine, which comprises a machine body and a tensile mechanism arranged on the machine body;
the stretching mechanism comprises a lower disc, an upper disc, a clamp and a connecting rod;
the upper disc and the lower disc are coaxially arranged, the lower disc is fixedly connected with the machine body, the upper disc is rotationally connected with the machine body, a boss is arranged at the central position of the upper disc, a plurality of clamps are annularly arranged on the upper disc around the center of the boss, involute-shaped guide grooves corresponding to the clamps are formed in the upper disc, each involute-shaped guide groove is formed in the lower disc, a connecting rod sequentially penetrates through the corresponding linear guide groove and each involute-shaped guide groove to be rotationally connected with each clamp, and the connecting rod can slide in the corresponding linear guide groove and each involute-shaped guide groove.
Further, a first base circle is drawn on the upper disc around the circle center of the upper disc, upper disc equal dividing points with the same number as the clamps are arranged on the circumference of the first base circle, involute of the first base circle is made on the upper disc by taking each upper disc equal dividing point as a starting point, and the involute is the central line of the involute guide groove;
drawing a second base circle with the diameter consistent with the first base circle on the lower disc around the circle center of the lower disc, projecting the bisection point of the first base circle to the circumference of the second base circle to form a lower disc bisection point, taking the lower disc bisection point as a starting point, and making tangent lines of the second base circle on the lower disc, wherein the tangent lines are the central lines of the linear guide grooves.
Further, the extending direction of the involute guide groove is opposite to the extending direction of the straight guide groove.
Further, the device also comprises a non-contact laser extensometer, wherein the non-contact laser extensometer is connected with the upper disc and is arranged above the clamp.
Further, a connecting hole is formed in the upper disc, and the non-contact laser extensometer is connected with the connecting hole through a supporting arm.
Further, the machine body comprises a frame, a driving motor, a rotating shaft and a guard plate, wherein the driving motor is installed in the frame, the driving motor is connected with the center of the upper disc through the rotating shaft, the guard plate is installed on the frame, and the lower disc is fixedly connected with the frame.
Further, the clamp comprises a base, a clamping piece and a force sensor; the base is rotationally connected with the connecting rod, and the clamping piece is connected with the base through the force sensor.
Further, the clamping piece comprises two clamping arms which are hinged, a tightening screw is arranged between the tail parts of the two clamping arms, the tightening screw is connected with one clamping arm, and hemispherical flat bottom balls are respectively embedded into the heads of the two clamping arms.
Further, the diameters of the lower disc and the upper disc are consistent.
Further, a bracket connecting hole is formed in the lower disc, and the lower disc is fixedly connected with the frame through the bracket connecting hole.
The involute type multi-axis tensile testing machine for the flexible material has the following advantages:
1. the involute guide groove is matched with the corresponding straight guide groove, so that the clamp can be pushed to reciprocate along the straight guide groove, and the minimum friction force in the movement of the mechanism is ensured because the thrust pressure angle to the clamp is 0.
2. The whole structure adopts a design mode of central symmetry, and when the upper disc rotates, all clamps in the circumferential direction can synchronously move in the mode of central symmetry, so that the flexible material sample to be tested is uniformly deformed along all directions of the circumference in the stretching-releasing process, and simultaneously, the synchronism and the equality of the tensile force are ensured.
3. Because of the special property of the involute structure, the displacement of the clamp in the forced movement process is in direct proportion to the rotating angle of the upper disc, so that the deformation state of the measured material sample can be controlled by controlling the rotating angle of the upper disc.
4. The device can be used for equiaxial loading-unloading cyclic stretching of flexible materials and elastomer materials, and can also be used for quasi-static stretching and multiaxial dynamic fatigue test of the flexible materials and the elastomer materials.
5. Can ensure that the stress on each position of the circumference of the sample is uniform and always synchronous in the loading or unloading process
6. In the loading or unloading process, the degree of uneven stress of the sample or inaccurate measurement result caused by factors such as mechanical friction is greatly reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic structural diagram of an involute type multi-axis tensile testing machine for flexible materials according to an embodiment of the present invention.
Fig. 2 is a schematic structural diagram of a hidden guard board of an involute type flexible material multi-axis tensile testing machine according to an embodiment of the invention.
Fig. 3 is a schematic structural diagram of an upper disc according to a first embodiment of the present invention.
Fig. 4 is a schematic structural diagram of a lower disc according to an embodiment of the present invention.
Fig. 5 is a schematic diagram of movement and stress provided by the first embodiment of the invention.
Fig. 6 is a schematic diagram of movement and stress provided by the first embodiment of the invention.
Fig. 7 is a schematic diagram of movement and stress provided by the first embodiment of the present invention.
Fig. 8 is a schematic diagram of movement and stress provided by the first embodiment of the invention.
Fig. 9 is a schematic diagram of a connection relationship between a clamp and a connecting rod according to an embodiment of the invention.
Fig. 10 is a schematic diagram of a connection relationship between an upper disc and a boss according to a first embodiment of the present invention.
Fig. 11 is a stress-strain experimental plot of a flexible body material provided in accordance with an embodiment of the present invention under equibiaxial deformation conditions.
Reference numerals: 1-a machine body; 2-stretching mechanism; 21-a lower disc; 22-upper disc; 23-clamping; 24-connecting rod; 3-involute guide slot; 4-a straight guide groove; 5-a first base circle; 51-upper disc bisection point; 6-involute; 7-a second base circle; 71-lower disc bisection point; 8-cutting lines; 9-a non-contact laser extensometer; 221-connecting holes; 10-supporting arms; 11-a frame; 12-driving a motor; 13-a rotating shaft; 14-guard plates; 15-a boss; 211-bracket connection holes; 25-a base; 26-clamping piece; 27-force sensor; 261-clip arms; 262-screwing the screw; 263-hemispherical flat bottom ball.
Detailed Description
The following description of the embodiments of the present invention will be made apparent and fully in view of the accompanying drawings, in which some, but not all embodiments of the invention are shown. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
Embodiment one:
FIG. 1 is a schematic diagram of an involute type multi-axis tensile testing machine for flexible materials according to an embodiment of the present invention; FIG. 2 is a schematic view of a hidden guard board of an involute type flexible material multi-axis tensile testing machine according to an embodiment of the invention; FIG. 3 is a schematic diagram of an upper disc according to a first embodiment of the present invention; FIG. 4 is a schematic diagram of a lower disc according to an embodiment of the present invention; FIG. 5 is a schematic diagram of a first embodiment of the present invention; FIG. 6 is a diagram showing a second motion and force principle provided by the first embodiment of the invention; FIG. 7 is a diagram showing a third motion and force principle provided by the first embodiment of the invention; FIG. 8 is a diagram showing a motion and force principle according to a first embodiment of the present invention; FIG. 9 is a schematic diagram of a connection relationship between a clamp and a connecting rod according to a first embodiment of the present invention; FIG. 10 is a schematic diagram illustrating a connection relationship between an upper disc and a boss according to a first embodiment of the present invention; FIG. 11 is a graph showing stress-strain experiments under equibiaxial deformation conditions for a flexible body material according to an embodiment of the present invention; as shown in fig. 1 to 11, the involute type multi-axis tensile testing machine for flexible materials provided by the invention comprises a machine body 1 and a tensile mechanism 2 arranged on the machine body 1;
the stretching mechanism 2 comprises a lower disc 21, an upper disc 22, a clamp 23 and a connecting rod 24;
the upper disc 22 and the lower disc 21 are coaxially arranged, the lower disc 21 is fixedly connected with the machine body 1, the upper disc 22 is rotationally connected with the machine body 1, a boss 15 is arranged at the center of the upper disc 22, the boss 15 is used for placing a flexible material sample to be tested, the height of the boss is designed to ensure that the sample is convenient to clamp by a clamp 23 when placed on the boss, in the stretching process, the vertical height of the sample from the upper disc 22 is always unchanged, namely no additional tensile force is generated due to the weight of the sample, the clamp 23 is multiple and is annularly arranged on the upper disc 22 around the center of the boss 15, the upper disc 22 is provided with involute-shaped guide grooves 3 corresponding to each clamp 23, the lower disc 21 is provided with a straight-line guide groove 4 corresponding to each involute-shaped guide groove 3, a connecting rod 24 sequentially penetrates through the corresponding straight-line guide groove 4 and the involute-shaped guide groove 3 to be rotationally connected with each clamp 23, and the connecting rod 24 can slide in the corresponding straight-line guide groove 4 and involute-shaped guide groove 3.
Specifically, a first base circle 5 is drawn on the upper disc 22 around the center of the upper disc 22, upper disc equally dividing points 51 with the same number as the clamps 23 are arranged on the circumference of the first base circle 5, involute 6 of the first base circle 5 is made on the upper disc 22 with each upper disc equally dividing point 51 as a starting point, and the involute 6 is the center line of the involute guide slot 3;
a second base circle 7 with the same diameter as the first base circle 5 is drawn on the lower disc 21 around the center of the lower disc 21, an upper disc bisector 51 on the first base circle 5 is projected onto the circumference of the second base circle 7 to form a lower disc bisector 71, the lower disc bisector 71 is taken as a starting point, a tangent 8 of the second base circle 7 is made on the lower disc 21, and the tangent 8 is the center line of the linear guide groove 4.
Taking the example that ten clamps 23 are installed on the upper disc 22, equally dividing the circumference of the first base circle 5 into ten parts, setting the equal dividing points 51 of the upper disc as P1, P2 and P3 … P10, taking each equal dividing point 51 of the upper disc as a starting point, and making involute 6 of the first base circle 5 on the upper disc 22, wherein the involute 6 is the central line of the involute guide groove 3; meanwhile, ten upper disc bisectors 51 on the circumference of the first base circle 5 are projected onto the circumference of the second base circle 7 to form lower disc bisectors 71, the ten lower disc bisectors 71 on the circumference of the second base circle 7 are Q1, Q2, Q3 … Q10, each lower disc bisector 71 is taken as a starting point, a tangent line 8 of the second base circle 7 is formed on the lower disc 21, and the tangent lines 8 are the center line of the linear guide groove 4.
In principle, during the rotation of the upper disc 22, the thrust of the involute guide slot 3 to the connecting rod 24 can drive the connecting rod 24 to always keep vertically moving in the involute guide slot 3 and the linear guide slot 4 due to the special property of the involute curve, i.e. if the connecting rod 24 is seen from above the upper disc 22, the sliding in the involute guide slot 3 can be observed; whereas if viewed from above the lower disc 21, it can be observed that the connecting rods 24 slide synchronously in the rectilinear guide grooves 4.
Due to the geometric relationship between the involute guide groove 3 and the linear guide groove 4 and the first base circle 5 and the second base circle 7, the connecting rod 24 can keep vertically sliding in the involute guide groove 3 and the linear guide groove 4 in the rotating process of the upper disc 22, and the situation of motion misplacement or motion locking caused by the over-high rotating speed of the upper disc 22 can be avoided. And because the involute guide groove 3 and the straight guide groove 4 are uniformly arranged along the circumference, along with the rotation of the upper disc 22, each connecting rod 24 can synchronously slide in the respective involute guide groove 3 and the straight guide groove 4, namely, the distance between each connecting rod 24 and the circle center is always the same at any moment.
As can be seen from fig. 4 to 7, the thrust direction of the involute guide groove 3 to the connecting rod 24 and the movement direction of the connecting rod 24 are always consistent during the rotation of the upper disc 22, and the thrust pressure angle is 0 along the tangential direction of the base circle, so that no additional friction force is generated during the movement.
Specifically, the extending direction of the involute guide groove 3 is opposite to the extending direction of the straight guide groove 4.
Specifically, the device further comprises a non-contact laser extensometer 9, wherein the non-contact laser extensometer 9 is connected with the upper disc 22 and is arranged above the clamp 23.
The non-contact laser extensometer 9 is adopted, and the non-contact laser extensometer 9 synchronously rotates along with the deformation of the sample, can always synchronously rotate with a specific area on the sample, tracks and captures the deformation state of the same area on the sample, and ensures the accuracy of deformation measurement.
During the stretching process, the strain is measured by the non-contact laser extensometer 9 and calculated by the data processing program of the experimental machine.
The calculation method comprises the following steps:
the involute tensile testing machine is designed to obtain the stress-strain experimental curve of the flexible body material under the equibiaxial deformation condition as shown in the figure.
Wherein the strain data is obtained by measuring and calculating the deformation of the gauge length during stretching, and the deformation of the gauge length is measured by a non-contact extensometer (or other non-contact deformation measuring device). Let the measurement distance of the gauge length on the rubber sample before the beginning of the experiment be L 0 The measurement distance of the gauge length section at any time in the stretching process after the experiment is started is L t The calculation formula of the tensile strain epsilon of the flexible body material sample corresponding to any moment is as follows:
the stress data is calculated by summing all force sensors measuring the stretching process and dividing by the side area of the circular tensile specimen. Assuming a total of n clamps, n sensors are provided, the diameter of the tensile sample is D, the thickness is t, and the force measured on each sensor at any time in the tensile process after the experiment is started is F i (i=1, 2, …, n), the calculation formula of the tensile stress σ of the flexible body material sample corresponding to the arbitrary moment is:
the strain state obtained by stretching the axes is the same as that under the absolute equibiaxial stretching condition through the elastic mechanical method.
Specifically, the upper disc 22 is provided with a connecting hole 221, and the non-contact laser extensometer 9 is connected with the connecting hole 221 through a supporting arm 10.
Specifically, the machine body 1 comprises a machine frame 11, a driving motor 12, a rotating shaft 13 and a guard plate 14, wherein the driving motor 12 is installed in the machine frame 11, the driving motor 12 is connected with the center of the upper disc 22 through the rotating shaft 13, the guard plate 14 is installed on the machine frame 11, and the lower disc 21 is fixedly connected with the machine frame 11.
Specifically, the lower disc 21 is provided with a bracket connection hole 211, and the lower disc 21 is fixedly connected with the frame 11 through the bracket connection hole 211.
Specifically, the clamp 23 includes a base 25, a clamp 26, and a force sensor 27; the base 25 is rotatably connected with the connecting rod 24, the clamping piece 26 is connected with the base 25 through the force sensors 27, each clamp 23 is provided with a force sensor 27, and the tensile force measured by each force sensor 27 is the force on the clamp 23 where the force sensor 27 is located.
Specifically, the clamping piece 26 includes two articulated clamping arms 261, a tightening screw 262 is disposed between the tail portions of the two clamping arms 261, the tightening screw 262 is connected with one clamping arm 261, and hemispherical flat bottom balls 263 are respectively embedded in the heads of the two clamping arms 261.
When the sample is clamped, the force of the two clamping arms 261 on the clamping end of the sample can be controlled by screwing the screw 262, so that the clamping and the disassembly of the sample are facilitated; wherein the hemispherical flat bottom ball 263 ensures that the gripping section can rotate synchronously with the rotation of the sample during loading.
Through the anchor clamps 23 that this application provided, guarantee that clamping force is enough, and can be along with sample deformation synchronous rotation, guarantee that the sample is in the state of evenly stretching all the time.
Specifically, the diameters of the lower disc 21 and the upper disc 22 are uniform.
Specifically, the groove widths of the plurality of involute guide grooves 3 on the upper disk 22 are uniform, the groove widths of the plurality of straight guide grooves 4 on the lower disk 21 are uniform, and the involute guide grooves 3 are uniform with the groove widths of the straight guide grooves 4.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention.
Claims (8)
1. An involute type multi-axis tensile testing machine for flexible materials is characterized by comprising a machine body and a tensile mechanism arranged on the machine body;
the stretching mechanism comprises a lower disc, an upper disc, a clamp and a connecting rod;
the upper disc and the lower disc are coaxially arranged, the lower disc is fixedly connected with the machine body, the upper disc is rotationally connected with the machine body, a boss is arranged at the central position of the upper disc, a plurality of clamps are annularly arranged on the upper disc around the center of the boss, involute-shaped guide grooves corresponding to the clamps are formed in the upper disc, straight-line guide grooves corresponding to the involute-shaped guide grooves are formed in the lower disc, the connecting rods sequentially penetrate through the corresponding straight-line guide grooves and the involute-shaped guide grooves to be rotationally connected with the clamps, and the connecting rods can slide in the corresponding straight-line guide grooves and the involute-shaped guide grooves;
the method for determining the involute guide groove comprises the following steps: drawing a first base circle around the center of the upper disc on the upper disc, wherein the circumference of the first base circle is provided with upper disc equal dividing points with the same number as the clamps, taking each upper disc equal dividing point as a starting point, and making involute of the first base circle on the upper disc, wherein the involute is the central line of the involute guide groove;
the method for determining the linear guide groove comprises the following steps: drawing a second base circle with the diameter consistent with that of the first base circle on the lower disc around the circle center of the lower disc, projecting the bisection point of the first base circle onto the circumference of the second base circle to form a lower disc bisection point, and taking the lower disc bisection point as a starting point, and making tangent lines of the second base circle on the lower disc, wherein the tangent lines are the central line of the linear guide groove;
the extending direction of the involute guide groove is opposite to the extending direction of the straight guide groove.
2. The involute type flexible material multiaxial tensile testing machine according to claim 1, further comprising a non-contact laser extensometer connected with the upper disc and disposed above the clamp.
3. The involute type multi-axis tensile testing machine for flexible materials according to claim 2, wherein a connecting hole is formed in the upper disc, and the non-contact type laser extensometer is connected with the connecting hole through a supporting arm.
4. The involute type multi-axis tensile testing machine for flexible materials according to claim 1, wherein the machine body comprises a frame, a driving motor, a rotating shaft and a guard plate, the driving motor is installed in the frame, the driving motor is connected with the center of the upper disc through the rotating shaft, the guard plate is installed on the frame, and the lower disc is fixedly connected with the frame.
5. The involute type flexible material multi-axis tensile testing machine according to claim 1, wherein the clamp comprises a base, a clamping piece and a force sensor; the base is rotationally connected with the connecting rod, and the clamping piece is connected with the base through the force sensor.
6. The involute type multi-axis tensile testing machine for flexible materials according to claim 5, wherein the clamping piece comprises two clamping arms hinged to each other, a tightening screw is arranged between the tail parts of the two clamping arms, the tightening screw is connected with one clamping arm, and hemispherical flat bottom balls are respectively embedded in the heads of the two clamping arms.
7. The involute type multi-axis tensile testing machine for flexible material according to claim 1, wherein the diameters of the lower disc and the upper disc are identical.
8. The involute type multi-axis tensile testing machine for flexible materials according to claim 4, wherein a bracket connecting hole is formed in the lower disc, and the lower disc is fixedly connected with the frame through the bracket connecting hole.
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| CN111285313A (en) * | 2018-12-10 | 2020-06-16 | 上海宝群医疗科技有限公司 | Ampoule bottle processing equipment |
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