CN111272569A - Experimental device for measuring Young modulus and shear modulus of metal based on combined deformation method - Google Patents

Abstract

The invention discloses a device for measuring Young modulus and shear modulus of metal based on a combined deformation method, which comprises a combined deformation mechanism, a stress application mechanism and a telescopic suspension rod measuring mechanism which are arranged on a base, wherein one end of a support I is fixed on the base, the other end of the support I is fixed with a fixed end of a three-jaw drill chuck I, and a material to be measured is clamped at a clamping end of the three-jaw drill chuck I; the clamping end of the third claw drill chuck clamps one end of a cantilever beam, and the tail end of the cantilever beam is suspended with a force applying mechanism capable of adjusting the force; the fixed ends of the two telescopic suspension rods are hooped on the iron column in a one-to-one mode, and the telescopic suspension rods can move on the iron column; and the two displacement sensors are respectively used for measuring the displacement change of the second support and the displacement change of the tail end of the cantilever beam. The device can measure the Young modulus and the shear modulus through one-time experiment.

Description

An experimental device for measuring Young's modulus and shear modulus of metals based on combined deformation method

technical field

The invention relates to the technical field of measuring tools, in particular to an experimental device for measuring Young's modulus and shear modulus of metals based on a combined deformation method.

Background technique

The existing Young's modulus meter using the optical lever mirror ruler method to measure the principle of small deformation has a single measurement parameter, that is, only the Young's modulus of the material can be measured. Moreover, the optical lever amplification method is a static loading method. Due to the large load, slow loading speed, and the existence of a relaxation process, it generally cannot truly reflect the change of the internal structure of the material.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide an experimental device for measuring Young's modulus and shear modulus of metals based on the combined deformation method. The combined deformation method in mechanics not only solves the problems that traditional instruments are large and cumbersome, complicated to adjust, and cumbersome to replace materials Shortcomings, and can simultaneously measure the Young's modulus and shear modulus of the material.

In order to achieve the above purpose, the present invention provides the following solutions: the present invention provides a device for measuring Young's modulus and shear modulus of metals based on a combined deformation method, including a combined deformation mechanism, a force-enhancing mechanism and a flexible mechanism arranged on the base. Telescopic cantilever measuring mechanism,

The combined deformation mechanism includes a bracket 1, a bracket 2, a cantilever beam and three three-claw drill chucks. One end of the bracket 1 is fixed on the base, and the other end is fixed with the fixed end of the three-claw drill chuck 1. The clamping end of the claw drill chuck 1 holds the material to be tested; the two ends of the bracket 2 are respectively fixed with the fixed ends of the three-claw drill chuck 2 and the three-claw drill chuck 3, and the clamp of the three-claw drill chuck 2 is respectively fixed. The holding end clamps the other end of the material to be tested, the clamping end of the three-jaw drill chuck 3 clamps one end of the cantilever beam, and the end of the cantilever beam is suspended with the force-adjustable force. mechanism;

The telescopic suspension rod measuring mechanism includes two telescopic suspension rods, a vertical iron pillar is fixed on the base, and the fixed ends of the two telescopic suspension rods are fastened on the iron pillars one above the other. The position of the telescopic suspension rod on the iron column can be moved; a displacement sensor is installed on the telescopic end of the telescopic suspension rod, and the two displacement sensors are respectively used to measure the displacement change of the second bracket and the displacement change of the tail end of the cantilever beam .

Preferably, four feet of the base are respectively provided with anchor nuts for adjusting the height of the base.

Preferably, the first bracket is a right-angle L-shaped bracket, the vertical edge of the bracket is vertically threaded on the base, and the horizontal edge of the bracket is used to screw the first three-jaw drill chuck.

Preferably, the second bracket is a right-angle L-shaped bracket, two sides of the bracket are placed horizontally, and the two sides are respectively used for screwing the second three-jaw drill chuck and the third three-jaw drill chuck.

Preferably, a plastic thin disc is connected to the right-angled corner of the second bracket by hot melt adhesive; the displacement sensor installed on the telescopic end of a telescopic suspension rod is connected to the circular disc by hot melt adhesive.

Preferably, the three three-jaw drill chucks control the size of the clamping diameter of the three-jaw chuck end by rotating the rotary wheel on the three-jaw drill chuck body.

Preferably, the forcing mechanism is a hanging basket suspended from the tail end of the cantilever beam through three steel wires, and weights are placed on the hanging basket.

Preferably, the telescopic suspension rods are telescopic rods, and the telescopic ends of the two telescopic rods are respectively connected with the first displacement sensor and the second displacement sensor through hot melt glue.

Preferably, the first displacement sensor is connected with the tail end of the cantilever beam by hot melt glue.

Preferably, the fixed end of the retractable suspension rod is a two-lobed type that is interlocked with each other, the inner side of each lobe is provided with a groove that matches the outer wall of the iron column, and each lobe is symmetrically provided with flat-head bolts. The flat head bolt can adjust the tightness of the telescopic suspension rod and the iron column, and can also adjust the height of the telescopic suspension rod on the iron column.

The present invention has achieved the following technical effects with respect to the prior art:

The experimental device for measuring Young's modulus and shear modulus of metals based on the combined deformation method in the present invention is light and compact, simple to adjust, simple to read, convenient to replace materials, and can measure Young's modulus and shear modulus through one experiment Modulus, which can truly reflect the changes in the internal structure of the material, has smaller errors than traditional measuring instruments.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings required in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some of the present invention. In the embodiments, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without any creative effort.

Fig. 1 is the overall structure schematic diagram of the experimental device of the present invention;

Fig. 2 is the structure diagram of bracket one;

Figure 3 is a schematic structural diagram of a three-jaw drill chuck;

4 is a schematic diagram of the connection between a bracket one and a three-jaw drill chuck holding a material to be tested;

5 is a schematic diagram of a telescopic suspension rod measuring mechanism;

Figure 6 is a structural diagram of the groove of the fixed end of the retractable suspension rod;

Fig. 7 is a schematic diagram of an afterburning mechanism;

Figure 8 is a schematic diagram of data calculation;

Among them, 1 is the base; 2 is the bracket one; 3 is the three-jaw drill chuck one; 4 is the material to be tested; 5 is the three-jaw drill chuck two; 6 is the bracket two; 9 is the cantilever beam; 10 is the displacement sensor one; 11 is the retractable suspension rod one; 12 is the iron column; 13 is the retractable suspension rod two; 14 is the displacement sensor two; 15 is the rotary wheel; 17 is the hanging basket; 18 is the reading mechanism; 19 is the weight; A is the second contact point of the displacement sensor; B is the first contact point of the displacement sensor; y ₁ is the deformation amount at A; y ₂ is the deformation amount at B.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

The purpose of the present invention is to provide an experimental device for measuring Young's modulus and shear modulus of metals based on the combined deformation method. The combined deformation method in mechanics not only solves the problems that traditional instruments are large and cumbersome, complicated to adjust, and cumbersome to replace materials Shortcomings, and can simultaneously measure the Young's modulus and shear modulus of the material.

In order to make the above objects, features and advantages of the present invention more clearly understood, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

As shown in Figures 1-7, the present invention provides an experimental device for measuring Young's modulus and shear modulus of metals based on the combined deformation method, including: a base 1, an iron column 12, a combined deformation mechanism, a force application mechanism, and a flexible mechanism. Telescopic cantilever measuring mechanism.

specifically:

(1) The base 1, on one side of the base 1, there is an iron pillar 12 about 3 cm away from the edge, and the iron pillar 12 is connected with the base 1 in a threaded connection.

Combination deformation mechanism:

(2) Connect a short longitudinal 90-degree turning bracket 1 2 on the upper corner of the base 1 by screwing.

(3) Connection structure The three-claw drill chuck has two ends, one end is the threaded fixed end, and the other end is the three-claw fixed end where the three claws are directly contacted and fixed. There is a rotary wheel 15 on the body of the three-jaw drill chuck, which can adjust the thickness of the three-jaw drill chuck. Three such connection structures are used in the present invention, namely three-jaw drill chuck 1 3 , three-jaw drill chuck 2 5 and three-jaw drill chuck 3 8 .

(4) The threaded fixed end of the three-jaw drill chuck 1 3 is connected to the bracket 1 2, and the three-jaw fixed end of the three-jaw drill chuck is connected to one end of the material 4 to be tested. It idling.

(5) Make another bracket 2 6 with threads at both ends of the lateral corner of 90 degrees, wherein a thin plastic wafer 7 is connected to the bracket 2 6 by hot melt at the right angle of 90 degrees. The other end of the material to be tested 4 is connected with the three-claw end of the three-jaw drill chuck 2 5 , and the other end of the three-jaw drill chuck 2 5 is connected with the threaded end of the bracket 2 6 .

(6) The threaded end of the three-claw drill chuck 38 and the threaded end of the bracket 26 are threadedly connected, and the three-claw end and the cantilever beam 9 are fixed by three claws to ensure no idling.

Afterburner:

In the present invention, the discrete force application method is adopted, and three steel wires 16 are used to form a small hanging basket 17 and hang at the tail end of the cantilever beam 9 . The weight 19 is used to add force, and a force is applied to read the number through the reading mechanism 18 connected with the displacement sensor one 10 to record.

Retractable suspension rod measuring mechanism:

The present invention adopts two identical retractable suspension rods, the shape of which is a cylindrical cylinder, one end of which is flat, and is connected with the displacement sensor by hot glue, and a groove completely nested with the iron column 12 is opened at the other end, Make the groove and the iron pillar 12 completely nested, hit two bolts on both sides of the cylinder, fix the cylinder on the iron pillar 12 with flat-top iron nails, and move the cylinder up and down by tightening the iron nails. At the same time, the cylinder can be retracted and retracted forward and backward by rotating the screw thread to make it easier to adjust.

There are two displacement sensors connected with the signal of the reading mechanism 18, so two retractable suspension rods are designed, which are placed one above the other and one below the other. The other ends of the two telescopic suspension rods are respectively connected with the displacement sensor 1 10 and the displacement sensor 2 14 through a hot melt. The displacement sensor 2 14 connected to the retractable suspension rod 2 13 is placed on the wafer 7 on the right-angled corner of the bracket 2 6 , and the sensor is also glued to the wafer 7 by hot sol, so that the small displacement of the bracket 2 6 changes. It can be detected by the sensor, and then read out by the reading mechanism 18 in time.

The retractable cantilever 11 is also connected to the displacement sensor 10 through a hot sol, and the other end of the sensor is connected to the cantilever beam 9 through a hot sol. The connection is required to be relatively tight, so that the descending displacement of the rod caused by the force can pass through in time. The displacement sensor is monitored and finally converted into data and reflected in the reading display device.

The specific steps for using the experimental device for measuring Young's modulus and shear modulus of metals based on the combined deformation method are as follows:

(1) First adjust the height of the base 1. There are nuts on the four corners of the base 1, and the height of the base 1 can be adjusted to make it balanced.

(2) Install the iron column 12, the combined deformation mechanism, the forcing mechanism, the retractable suspension rod measuring mechanism and its reading mechanism 18, install the sample to be tested in the corresponding position, and fix the sample firmly on both sides to prevent it from happening. idling.

(3) Connect the reading mechanism, clear it, reset it, and restore it to the initial state.

(4) Prepare the weight 19, hang the tray and the weight 19 in the hanging basket 17 on the cantilever beam 9, so that the sample to be tested is straight and stable.

The discrete afterburning method is adopted, with the weight of the weight 19 being the size of the nominal force, each time a weight 19 is added, the data of the two reading mechanisms 18 are respectively recorded, and several groups are measured to obtain multiple groups of metal measurement data.

(5) Input several sets of measured data into the Origin software, firstly, take the force F as the horizontal axis and the deformation variable y ₁ as the vertical axis; then take the force F as the horizontal axis, and the difference between the sensor measurement data (y ₂ -y ₁ ) Draw a graph for the vertical axis, get a coordinate graph with two straight lines, and read out the slope value.

(6) Measure the diameter d of the metal bar to be measured, and use a spiral micrometer to measure the diameters of the upper, middle and lower positions of the metal bar, and then take the average value of the three measurement results of the spiral micrometer as the metal bar to be measured. diameter d.

(7) Use a meter ruler to measure the length x 1 of the metal rod to be tested, the length x ₂ of the connecting rigid rod and the length x _{3 of} the rigid rod.

As shown in Figure 8, after measuring the above values, the data calculation principle is as follows:

By applying a force F at point B and the translation and equivalent relationship of the force, the sample CD can be deformed in bending and torsion, and two points will be generated at point A of the sample CD and point B of the rigid rod AB. vertical displacement. It can be measured by the displacement sensor, the descending displacement generated by point A is y ₁ , and the descending displacement generated by point B is y ₂ . y ₁ reflects the displacement caused by bending deformation, and y ₂ -y ₁ reflects the displacement caused by torsional deformation. Through the relationship between the force and the bending deformation and torsional deformation of the metal material, the diameter of the metal and the two displacements, the The Young's modulus, shear modulus and Poisson's ratio of metal materials can be obtained. The specific formula is derived as follows:

After loading the force F, through the translation and equivalence of the force, the force F can produce a bending deformation and a torsional deformation at point A, a total of two deformations.

where the bending deformation can be reflected by y ₁ :

The length of the sample to be tested is measured as x ₁ , and the length of the connecting rigid device is x ₂

According to the differential equation of the deflection line, the relationship between the deformation of the cantilever beam 9 and the loading of the force F is:

In the experimental schematic diagram, AC is a connecting rigid rod, which will not deform itself, and its greatest function is to facilitate the replacement of the sample. Through several sets of experimental observations, the bending deformation of the sample is very small at the bending end of the sample, so we regard the connecting rigid rod AC as the extension of the sample CD. In the calculation of the deflection line equation, we use x ₁ +x ₂ as the length of the specimen. It is confirmed by multiple sets of experimental data that the above-mentioned processing methods have little effect on the error of the experimental results and can be ignored. therefore:

x=l=x ₁ +x ₂

get:

so:

Therefore, as long as the length x ₁ of the sample, the length x ₂ of the connecting rigid rod, the diameter d and y ₁ are known, the Young's modulus E of the sample can be obtained.

And y ₂ -y ₁ can reflect the torsional deformation:

The length of the rigid rod is measured as x ₃

Measure two displacements y ₁ , y ₂ , and make the difference y ₂ -y ₁

Through arc length l = central angle θ * radius x ₃

Since Δy ₂ -Δy ₁ is much smaller than x ₃ , y ₂ -y ₁ is approximately regarded as the arc length l

From the knowledge of material mechanics, for a solid metal cylinder:

The torque produced by the force F is: T=F*x ₃

In material mechanics, the relationship between torque, shear modulus and torsion angle is:

so:

得到：bring in

get:

so:

Therefore, as long as y ₁ , y ₂ , the diameter d of the sample to be tested, and the length of the rigid rod x ₃ are measured, the shear modulus of the sample to be tested can be obtained.

By adding weights 19 continuously, recording the indications of the displacement sensors y ₁ and y ₂ under different weights 19, by plotting F and y ₁ , and F and y ₂ -y ₁ , the slope k ₁ can be obtained and k ₂ .

Substitute E and G at the same time.

In the present invention, specific examples are used to illustrate the principles and implementations of the present invention, and the descriptions of the above embodiments are only used to help understand the method and the core idea of the present invention; There will be changes in the specific implementation manner and application scope of the idea of the invention. In conclusion, the contents of this specification should not be construed as limiting the present invention.

Claims (10)

1. the device of measuring Young's modulus of metal and shear modulus based on combined deformation method, it is characterized in that: comprise the combined deformation mechanism that is arranged on the base, the forcing mechanism and the telescopic suspension rod measuring mechanism, The combined deformation mechanism includes a bracket 1, a bracket 2, a cantilever beam and three three-claw drill chucks. One end of the bracket 1 is fixed on the base, and the other end is fixed with the fixed end of the three-claw drill chuck 1. The clamping end of the claw drill chuck 1 holds the material to be tested; the two ends of the bracket 2 are respectively fixed with the fixed ends of the three-claw drill chuck 2 and the three-claw drill chuck 3, and the clamp of the three-claw drill chuck 2 is respectively fixed. The holding end clamps the other end of the material to be tested, the clamping end of the three-jaw drill chuck 3 clamps one end of the cantilever beam, and the end of the cantilever beam is suspended with the force-adjustable force. mechanism; The telescopic suspension rod measuring mechanism includes two telescopic suspension rods, a vertical iron pillar is fixed on the base, and the fixed ends of the two telescopic suspension rods are fastened on the iron pillars one above the other. The position of the telescopic suspension rod on the iron column can be moved; a displacement sensor is installed on the telescopic end of the telescopic suspension rod, and the two displacement sensors are respectively used to measure the displacement change of the second bracket and the displacement change of the tail end of the cantilever beam . 2. The device for measuring Young's modulus and shear modulus of metal based on combined deformation method according to claim 1, wherein the four feet of the base are respectively provided with a height adjustment device for adjusting the height of the base. Anchor nuts. 3. The device for measuring Young's modulus and shear modulus of metal based on combined deformation method according to claim 1, is characterized in that: described bracket one is a right-angle L-shaped bracket, and the vertical side of the bracket is vertically threaded on the On the base, the horizontal side of the bracket is used for screwing the first three-jaw drill chuck. 4. The device for measuring Young's modulus and shear modulus of metal based on combined deformation method according to claim 1, wherein the bracket two is a right-angle L-shaped bracket, and both sides of the bracket are placed horizontally, And the two sides are respectively used for screwing the second three-jaw drill chuck and the third three-jaw drill chuck. 5. The device for measuring Young's modulus and shear modulus of metal based on combined deformation method according to claim 4, wherein: the right-angled corner of the bracket two is connected with a plastic thin disc by hot melt adhesive ; The displacement sensor installed on the telescopic end of one of the telescopic suspension rods is connected with the wafer by hot melt glue. 6. the device for measuring Young's modulus of metal and shear modulus based on combined deformation method according to claim 1, is characterized in that: three three-claw drill chucks pass the rotary wheel on the three-claw drill chuck body by rotating To control the size of the clamping diameter of the three-jaw chuck end. 7. The device for measuring Young's modulus and shear modulus of metal based on combined deformation method according to claim 1, characterized in that: the forcing mechanism is a hanging basket suspended on the tail end of the cantilever beam through three steel wires , the hanging basket is used to place weights. 8 . The device for measuring Young's modulus and shear modulus of metals based on combined deformation method according to claim 1 , wherein the telescopic suspension rod is a telescopic rod, and the telescopic ends of the two telescopic rods pass through the The hot melt adhesive is respectively connected with the first displacement sensor and the second displacement sensor. 9 . The device for measuring Young's modulus and shear modulus of metals based on the combined deformation method according to claim 8 , wherein the displacement sensor 1 is connected with the tail end of the cantilever beam by hot melt glue. 10 . 10. The device for measuring Young's modulus and shear modulus of metals based on combined deformation method according to claim 8, characterized in that: the fixed end of the telescopic suspension rod is a two-lobed type that is fastened to each other, and each The inner side of the petal is provided with a groove that matches the outer wall of the iron column, and each petal is provided with a flat-head bolt symmetrically. By adjusting the flat-head bolt, the tightness of the retractable suspension rod and the iron column can be adjusted, and the retractable suspension rod can also be adjusted. high and low position on the iron pillar.

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