CN1704748A - Electrostatic capacitance type apparatus for measuring Young's modulus - Google Patents

Abstract

This invention provides a static condensed device for testing young's modulus, which is a condenser composed of an upper conductive metallic plate and a lower conductive metallic plate, one of which is taken as a mobile plate fixed by connecting an insulation material with a metal rod, the other pole plate is used for adjusting the distance between the up and down copper plates to constitute a static condensed young's modulus test device. When a slight charge happens to the distance between the plates, the capacitance changes accordingly in terms of the theory of gap variable of a plane condenser to test the metal young's modulus valve of rigid material.

Description

A kind of electrostatic capacitive is surveyed the device of Young modulus

Technical field:

The invention belongs to electronic technology field, it is particularly related to solid rigid material such as the tinsel Young modulus value technology surveyed.

Background technology:

As everyone knows, Young modulus is meant that the elasticity coefficient of deformation size takes place solid under the effect of external force, and meaning is the physical quantity that characterizes the low ability of anti-deformation of solid material.

According to present most a kind of methods that adopt the optical lever method to survey Young modulus, it is made of one group of telescope, support, tinsel securing member, plane of reflection mirror, optical lever, counterweight, micrometer caliper, vernier caliper, meter ruler.Measurement is that optical lever is placed on the hollow cylinder surface, aim at plane of reflection mirror with telescope, regulate the telescope objective focal length, make it can clearly see scale label on the telescope, on carrying a tray under the tinsel that stretches, progressively place 1 kilogram of counterweight weight then, 1 kilogram of counterweight of every increase, tinsel just extends a tiny length, and at this moment optical lever just changes a very little angle.According to the plane geometry principle, can extrapolate tinsel variable elongation amount, measurement mechanism and principle are seen accompanying drawing 1 and accompanying drawing 2 explanations.

By the formula theorem

$\frac{F}{S}=Y\frac{\mathrm{\ΔL}}{L}$

Draw Young modulus

$Y=\frac{8\mathrm{LD}}{{\mathrm{\πd}}^{2}b}\frac{\mathrm{\ΔF}}{\mathrm{\Δn}}$

In the formula

L---be the former length of tinsel;

d ²---be wire diameter;

D---plane of reflection mirror is apart from telescope length;

Δ F---counterweight pulling force;

B---optical lever brachium;

N, n ₀---rod reading;

Δ n---telescope scale changes scale value.

By geometric relationship

$\tan \mathrm{\α}=\frac{\mathrm{\ΔL}}{b},\tan 2\mathrm{\α}=\frac{n-n_0}{D}---\left(1\right)$

Because α is very little, can be similar to

$\mathrm{\α}=\frac{\mathrm{\ΔL}}{b},2\mathrm{\α}=\frac{n-n_0}{D}---\left(2\right)$

Can get thus

$\mathrm{\ΔL}=\frac{b}{2D}(n-n_0)---\left(3\right)$

Generally speaking, be 4cm～8cm, D is 1m～2m, and optical lever enlargement factor (2D/b) can reach 20～100 times.

Then

$\begin{array}{c}F=\frac{\mathrm{\π}{d}^2\mathrm{bY}}{8\mathrm{LD}}(n-n_0)\\ Y=\frac{8\mathrm{LD}}{{\mathrm{\πd}}^{2}b}\frac{\mathrm{\ΔF}}{\mathrm{\Δn}}\end{array}---\left(4\right)$

According to formula (4), need only measure L, d, b, Δ F and n and n ₀After, can obtain Young modulus Y value.

The survey instrument step that Young modulus that this method is surveyed relates to is many, operating personnel are easy to generate the collimation error when regulating telescope, make the accuracy and the consistance of measurement relatively poor, the systematic error of introducing is bigger than normal, makes the Young modulus value that is drawn depart from bigger at last.

Summary of the invention:

For overcoming limitation and the deficiency that the optical lever method is measured, the invention provides the device that electrostatic capacitive is surveyed Young modulus, characteristics such as it is higher to utilize measurement device metal Young modulus value of the present invention to have an accuracy, and error is less than normal, and consistance is better.

A kind of electrostatic capacitive provided by the invention is surveyed the device (as shown in Figure 4) of Young modulus, it is characterized in that it comprise support 1, securing member 2, crossbeam 3, rigid material 4, connecting link 5, counterweight 6, weight tray 7, insulating sleeve 8, the cylinder axis of guide 9, casing cover plate 10, go up conductive metal sheet 11, down conductive metal sheet 12, insulating material panel 13, locating shaft 14, gap adjustment threaded rod 15, two conical gear and three transmission gear means 16, digital display plates 17, regulate knob 18, shell 19, horizontal base wads and regulate knob 20, device end seat 21; Described two conical gear and three transmission gear means 16 by horizontal conical gear be connected a screw rod with knob 18, vertically conical gear is connected a following gear, laterally conical gear is formed with vertical bevel gearing; Gap adjustment threaded rod 15 and two conical gear are connected with a gear (following gear) in three transmission gear means 16 and are used for that copper coin 12 and gap adjustment threaded rod 15 are highly regulated down, gap adjustment threaded rod 15 is connected with insulating material panel 13, insulating material panel 13 left and right sides are connected with locating shaft 14 about in the of respectively, its below is an insulating sleeve, insulating material panel 13 embeds a following copper coin 12, the top is a copper coin 11 on another, they connect the moving plate effect of playing capacitor by connecting link 5, can move up and down, insulating sleeve 8 is connected with weight tray 7, fix two cylinder axis of guides 9 respectively in weight tray 7 both sides, two circular holes that this cylinder axis of guide 9 passes casing cover plate 10 play positioning action up and down, counterweight 6 can be placed in weight tray 7 tops, connecting link 5 connects a fixedly securing member 2 of rigid material 4, one end of the fastening rigid material 4 in securing member 2 tops, the other end of rigid material 4 is connected with device crossbeam 3 by securing member, the crossbeam both sides are fixed by bolts on the support 1, support 1 is connected with device end seat 21, has four horizontal base wads that are used for the regulating device level to regulate knob 20 on the device end seat 21.

Need to prove that rigid material recited above is meant that solid is subjected to have elastic recovery properties under the external force effect, that is to say and cancelling under the situation of compelling force that solid material can return to virgin state, it can be a tinsel; Described upward conductive metal sheet and following conductive metal sheet are meant the metal plate material of conduction, and it can be a copper coin, also can be aluminium sheet etc.

A kind of electrostatic capacitive provided by the invention is surveyed the using method of the device of Young modulus, is to adopt following step:

It is hollow and fixing tight that the first step is passed two anchor clamps with the rigid material (as tinsel) of Young modulus to be measured.

Second step was measured the diameter and the length of rigid material (as tinsel) respectively with milscale and meter ruler.

The 3rd step was adjusted the capacity plate antenna gap with regulating knob, generally got about 3～5mm.

The 4th step device for opening working power is also regulated digital capacitance instrument demonstration null value, can eliminate spuious and distributed capacitance.

The 5th step was selected the rigid material of different-diameter and material for use, and the weight of counterweight can be done by the difference requirement.This device increases or reduces one kilogram of counterweight one by one, notes each capacitance value data again.

The 6th step just can be calculated the Young modulus of the rigid material of surveying again by correlation formula according to the data of record.

Principle of work of the present invention: become the gap principle according to the conducting metal plate condenser, when subtle change took place distance between the conducting metal flat board, electric capacity changed thereupon.Therefore, constitute capacitor with two conducting metal flat boards (as copper coin), one of them plate insulate to be connected and fixed with Metallic rod with insulating material and makes movable plate, about another piece is used to regulate copper coin between distance.Copper coin and the insulation of other link prevent that the distribution of plate electric weight from changing, and influence measurement result.Tested rigid material (as tinsel) is connected on the Metallic rod, and fastening with anchor clamps.Measure former length and diameter respectively with meter ruler and micrometer caliper before measuring.On the measuring table with rigid material (as tinsel) coupling arrangement on, place the counterweight weight, every increase or when reducing by 1 kilogram of counterweight weight, copper coin gap up and down reduces or increases, electric capacity increases or minimizing.Can accurately measure the change value of electric capacity according to such physical parameter variable quantity, see accompanying drawing 3 explanations.

By formula

Can derive the Young modulus value

In the formula

Δ C---capacitance change;

Δ F---counterweight pulling force;

L---the former length of tinsel;

ε---capacitor specific inductive capacity;

Distance between d---two flat boards;

S _Gold---the tinsel cross-sectional area;

S _Plate---the plate condenser surface area.

Can draw the electric capacity original bulk according to principle is

As moving plate displacement d ₀After, its capacitance is

When d＜＜d ₀The time, so

D in the formula---initial distance;

d ₀---change distance.

And

Therefore by (6), (10) Shi Kede

Then

D wherein _Plate---wire diameter;

d _Gold---metal plate (copper coin) diameter.

According to (12) formula, measure capacitance Δ C, L, d _Plate, d _GoldΔ F just can get the mean value of Y.

Copper coin leads to the high accuracy number capacitance meter with two leads about inciting somebody to action during measurement, can intuitively read the capacitance of each variation.

Essence of the present invention is: become the gap principle according to plate condenser, when subtle change took place distance between the metal plate of conduction, electric capacity changed thereupon.Therefore, constitute capacitor with the metal plate (as copper coin) of two conductions, one of them plate insulate to be connected and fixed with Metallic rod with insulating material and makes movable plate, about another piece is used to regulate copper coin between distance; Form a kind of electrostatic capacitive and survey the device of rigid material (as tinsel) Young modulus.

Beneficial effect of the present invention:

The device that provides of the present invention is provided, can be by direct measurement capacitance variation amount again through calculating the Young modulus value, the parameter consistency of surveying good, can reduce survey instrument vernier caliper, telescope scale, overcome the subjective adjusting telescope collimation error simultaneously, reduced too much linear measure longimetry, this plant area space is little, and is simple in structure, convenient and practical, measurement mechanism is almost non-maintaining, saves cost.

Description of drawings

Fig. 1 is the existing device of surveying Young modulus by the optical lever principle

Wherein, 1. be securing member; 2. be support; 3. be tinsel; 4. be optical lever; 5. be level crossing; 6. be hollow cylinder; 7. be platform; 8. be counterweight; 9. be pallet; 10. be horizontal adjusting knob; 11. be the device base; 12. be scale; 13. be telescope; 14. be that connecting link 15. is that objective focal length is regulated knob; 16. be to sit at the end.

Fig. 2 is existing optical lever amplification principle

Wherein, A is a crossbeam; M is a level crossing; B is the optical lever brachium; Q is a tinsel; Y is a hollow cylinder; G is a platform; F is a counterweight; D is a mirror chi distance; P is a scale; M and M ' are the minute surface turned positions; N and n ₀It is rod reading; α is the optical lever deflection angle; C and c ' are the right cylinder upper and lower surfaces.

Fig. 3 is the change clearance-type plate condenser principle that the present invention adopts

Wherein, S is the sheet metal area; D is the pole plate dropping distance; D is the pole plate initial distance.

Fig. 4 is an electrostatic capacitive Young modulus device provided by the invention

Wherein, 1. support; 2. securing member; 3. crossbeam; 4 rigid materials (as tinsel); 5. connecting link; 6. counterweight; 7. weight tray; 8. insulating sleeve; 9. the cylinder axis of guide; 10. casing cover plate; 11. last copper coin; 12. following copper coin; 13. insulating material panel; 14. locating shaft; 15. gap adjustment threaded rod; 16. two conical gear and three transmission gear means shells; 17. digital display plate; 18. adjusting knob; 19 shells.; 20. horizontal base wad is regulated knob; 21. device end seat;

Embodiment

A kind of measurement Young modulus device wiry

As shown in Figure 4, connect a screw rod and knob at the horizontal conical gear 16 of the inner casing lower plate of device, vertically conical gear connects a following gear, this gear is connected with two other transmission gear, center threaded shaft 15 is connected with one of them gear and is used for 12 and 15 highly adjustings, this threaded shaft is connected with dielectric panel 15, the insulcrete left and right sides is located axostylus axostyle 14 up and down and is connected with one respectively, its below is an insulating sleeve, insulcrete embeds a copper coin 12, the top is another copper coin 11, it connects the moving plate effect that an axostylus axostyle 5 plays capacitor, can move up and down, insulating sleeve 8 is connected with weight tray 7, fix the circular shaft 9 of two guiding usefulness respectively in the pallet both sides, two round skies that this circular shaft passes casing cover plate 10 play positioning action up and down, counterweight 6 can be placed in the pallet top, but circular shaft 5 connects a fixing metal silk securing member 2, the top is a tinsel 4, its other end and securing member are fixed, and securing member is connected with device crossbeam 3, crossbeam both sides two steel pipes 1 of bolt, steel pipe is connected with device end seat 21, and its plate has four base wads 20 that are used for the regulating device level.

Claims (3)

1, a kind of electrostatic capacitive is surveyed the device of Young modulus, it is characterized in that it comprises support (1), securing member (2), crossbeam (3), rigid material (4), connecting link (5), counterweight (6), weight tray (7), insulating sleeve (8), the cylinder axis of guide (9), casing cover plate (10), last conductive metal sheet (11), following conductive metal sheet (12), insulating material panel (13), locating shaft (14), gap adjustment threaded rod (15), two conical gear and three transmission gear means (16), digital display plate (17), regulate knob (18), shell (19), horizontal base wad is regulated knob (20), device end seat (21); Described two conical gear and three transmission gear means (16) by horizontal conical gear be connected a screw rod with knob (18), vertically conical gear is connected a following gear, laterally conical gear is formed with vertical bevel gearing; Gap adjustment threaded rod (15) and two conical gear are connected with a gear (following gear) in three transmission gear means (16) and are used for that copper coin (12) and gap adjustment threaded rod (15) are highly regulated down, gap adjustment threaded rod (15) is connected with insulating material panel (13), insulating material panel (13) left and right sides is connected with locating shaft (14) about in the of respectively, its below is an insulating sleeve, insulating material panel (13) embeds a following copper coin (12), the top is copper coin on another (11), they connect the moving plate effect of playing capacitor by connecting link (5), can move up and down, insulating sleeve (8) is connected with weight tray (7), fix two cylinder axis of guides (9) respectively in weight tray (7) both sides, two circular holes that this cylinder axis of guide (9) passes casing cover plate (10) play positioning action up and down, counterweight (6) can be placed in weight tray (7) top, connecting link (5) connects a fixedly securing member (2) of rigid material (4), one end of securing member (2) the fastening rigid material in top (4), the other end of rigid material (4) is connected with device crossbeam (3) by securing member, the crossbeam both sides are fixed by bolts on the support (1), support (1) is connected with device end seat (21), has four horizontal base wads that are used for the regulating device level to regulate knob (20) on the device end seat (21).

2, a kind of electrostatic capacitive according to claim 1 is surveyed the device of Young modulus, it is characterized in that described rigid material (4) is meant that solid is subjected under the external force effect, has elastic recovery properties, that is to say and cancelling under the situation of compelling force, solid material can return to virgin state, and it can be a tinsel.

3, a kind of electrostatic capacitive according to claim 1 is surveyed the device of Young modulus, it is characterized in that described upward conductive metal sheet (11) and following conductive metal sheet (12) are meant the metal plate material of conduction, and it can be a copper coin, also can be aluminium sheet.

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