CN106128234A - Experimental provision and the method for Young's modulus is surveyed by the beam deflection method of simple harmonic oscillation - Google Patents

Abstract

Experimental provision and the method for Young's modulus is surveyed by the beam deflection method of simple harmonic oscillation, relate to a kind of young modulus measuring device and method, the present invention solves that the experimental principle of current Experiment of College Physics central sill bending method survey Young's modulus is single abstract, the problem that telescope adjustment difficulty is big.Apparatus of the present invention are included on pedestal and arrange two columns, one beams of metal two ends, square-section freely rides upon on the edge of a knife of column upper end, a copper framework is overlapped on beams of metal, lower end arranges force-sensing sensor, moving armature and iron block, lower section arranges electromagnet apparatus, and differential bridge, adjustable alternating-current voltage source, voltage amplification device and digital oscilloscope etc. that measurement apparatus is made up of two inductance coils and two adjustable resistances are constituted；The inventive method surveys the cycle of periodically variable bridge output voltage waveform by digital oscilloscope, obtains beams of metal spring oscillator and does the cycle of simple harmonic oscillation, substitutes into formula and calculates metal material Young's modulus.The present invention is applicable to the measurement of Young's modulus.

Description

Experimental provision and the method for Young's modulus is surveyed by the beam deflection method of simple harmonic oscillation

Technical field

The present invention relates to a kind of Experiment of College Physics device, the beam deflection method being specifically related to a kind of simple harmonic oscillation surveys poplar The experimental provision of family name's modulus and method.

Background technology

Under external force, the change of shape that solid is occurred, referred to as deformation.It can be divided into elastic deformation and plastic deformation Two classes.External force removes the complete restorable deformation of energy of rear object, referred to as elastic deformation.If the external force mistake being added on object Greatly, so that after external force is removed, object can not restore to the original state completely, and leaves residual deformation, the most referred to as plastic deformation.In this reality In testing, only study elastic deformation.To this end, the size of external force should be controlled, with ensure this external force remove after object resilient. Simplest deformation is bar-like object (or tinsel) by the elongation after external force and shortening.If an a length of L of object, sectional area is S, Along its length after force F, object elongation (or shortening) is Δ L.Ratio F/S is the active force in unit are, is referred to as stressing, Which determine the deformation of object；Ratios delta L/L is the specific elongation of object, referred to as strain, and it represents the size of object deformation.Press According to Hooke's law, the elastic limit internal stress at object is directly proportional to strain, proportionality coefficientIt is referred to as Young Modulus.

Experiment shows, Young's modulus is unrelated with the size of external force F, length L of object and sectional area S, and is solely dependent upon rod The material of (or tinsel).Young's modulus is to describe an important mechanics parameter of solid material elastic deformation ability, is selected One of foundation of mechanical component material, is parameter conventional in engineering.No matter it is elastomeric material, such as various metal materials, Or fragile material, such as glass, pottery etc., or other various new materials, such as fiberglass, carbon fibre composite etc., for Ensure the use of normal safe, will measure their Young's modulus.For a long time, the Young's modulus measuring material is generally adopted Use static stretch method, typically carry out on universal testing machine.This method load is big, and loading velocity is slow, there is relaxation mistake Journey, can increase measurement error, and be difficult to fragile material measure, and measures also inconvenient under condition of different temperatures.20th century The eighties, there are people's laser-holographic interferometry and laser speckle photography method that the Young's modulus of the carbon composite of aerospace field is entered Row is measured, and carrys out the impact on Young's modulus of the research material defect with this, achieves good effect.The nineties in 20th century, power Learn Young's modulus measuring method i.e. hang wire flexural resonance method to recommend to perform as national technical standard.This method can be Measure the Young's modulus of various material in the range of bigger high/low temperature, and certainty of measurement is higher.Static method except static stretch method, Also have static twist method, the method for Static bending etc.；Dynamic method except lateral resonance, also longitudinal resonance, torsional resonance etc..Additionally also Wave speed measurement method can be used, utilize continuous wave or impulse wave to measure Young's modulus.

Although kinetics Young's modulus measuring method i.e. hang wire flexural resonance method has many good qualities, but due to theory Formula is complicated, and principle is the most readily understood, and equipment is the most more complicated, and experiment difficulty is big, therefore in Experiment of College Physics at present frequently with Beam deflection method, measures the Young's modulus of metal material according to optical lever amplification principle.Optical lever amplification principle extensively should It is used in measurement technology, as low-angle change measured by ballistic galvanometer and light spot galvanometer.The most also have employing other one The most more advanced micro-displacement measurement method, such as current vortex sensor method, Michelson's interferometer method, method using in optic fiber displacement sensor Device method etc. measures the Young's modulus of metal material.Experiment of College Physics central sill bending method surveys metal material Young's modulus at present Experimental provision is primarily present following deficiency:

One, generally uses static stretch method to survey metal material Young's modulus, and principle is more single.

Its two, according to optical lever amplification principle, the amplification system consisted of optical lever, telescope and scale measures rectangle Sag curved under cross section metal beam midpoint, although method is ingenious, but principle is more abstract, the most readily understood, telescopical regulation Difficulty is bigger, and points for attention are the most, and directly utilizes telescope to carry out observing measurement by human eye, is very easy to tired Data are easily mistaken by labor, affect the accuracy of measurement result.

Its three, general use counterweight to apply pulling force to beams of metal, calculate pulling force with the nominal mass of counterweight inaccurate, thus Affect the accuracy of experimental result.

Summary of the invention

In order to overcome the above-mentioned deficiency of prior art, the present invention proposes the beam deflection method of a kind of simple harmonic oscillation and surveys Young mould The experimental provision of amount and method, experimental principle of the present invention is easily understood, and beams of metal spring oscillator is done simple harmonic quantity by described experimental provision The cycle T of vibration, is converted to the cycle T of periodically variable bridge output voltage, amplified device by the change of inductance value After amplification, waveform shows on digital oscilloscope, observes the waveform of bridge output voltage, measures its cycle T, experimental phenomena Intuitively, observe with measure more convenient.Electromagnet apparatus is used to make beams of metal spring oscillator do simple harmonic oscillation, easy to operate.

The present invention solves the experimental provision by the beam deflection method survey Young's modulus of simple harmonic oscillation of its technical problem: at base Arranging two columns on Zuo, each two column upper ends fix a steel edge of a knife, the blade of two edges of a knife is parallel to each other, a rectangle Cross section metal beam two ends freely ride upon on the edge of a knife of two column upper ends, overlap a copper frame on the beams of metal of square-section Frame, copper framework and beams of metal contact position, square-section are also edges of a knife, and the copper framework edge of a knife is located exactly on two columns The edge of a knife middle of end, arranges force-sensing sensor in copper framework lower end, and force-sensing sensor is by attachment means and a moving armature Being connected, moving armature is connected with an iron block by attachment means, arranges electromagnet apparatus below iron block.Force-sensing sensor is by connecing Mouth is connected with force-sensing sensor Mersure Controler, and force-sensing sensor is used for measuring pulling force size, namely rectangle suffered by copper framework Pulling force size suffered by cross section metal beam midpoint, and can be shown by force-sensing sensor measurement display screen.Electromagnet apparatus It is used for applying pulling force in iron block to square-section beams of metal by magneticaction, then discharges, so that copper framework, movable rank Ferrum, iron block do simple harmonic oscillation under the beams of metal effect of square-section, and can be adjusted by electromagnet apparatus operating current adjusting knob Joint pulling force size.Two identical iron cores of specification are separately positioned on two fixtures, and fixture is arranged on column, and fixture can Moving to change position along column, two identical inductance coils of specification are rotating around on two iron cores.Two inductor wires Circle and two adjustable resistances collectively form a differential bridge, adjustable alternating-current voltage source provide power supply, adjustable exchange to electric bridge Sinusoidal signal voltage amplitude and the frequency size of voltage source output can be adjusted by knob, and can be at adjustable alternating voltage Show on the display screen of source.The outfan concatenation operation amplifier one of electric bridge, as a backward voltage amplifier, voltage is put Big multiple can be adjusted by the size changing adjustable feedback resistance and adjustable input resistance, is put by the output voltage of electric bridge Greatly, then exporting through the operational amplifier two as output buffer, operational amplifier two is connected with digital oscilloscope by interface, The waveform of the bridge output voltage after amplifying can be shown by digital oscilloscope, observes and measures.

The beam deflection method of simple harmonic oscillation of the present invention is surveyed the experimental provision of Young's modulus and is surveyed metal material Young mould The experimental technique of amount, the detailed process of the method comprises the following steps:

Step one, by observing pedestal level gauge, adjust the pedestal leveling serew on pedestal, make square-section beams of metal water Flat；

Step 2, along column movable clamp one and fixture two, make moving armature be positioned in the middle of iron core one and iron core two, pass through Adjustable alternating-current voltage source function switching key, shows that adjustable alternating-current voltage source exports on adjustable alternating-current voltage source display screen respectively Sinusoidal signal voltage amplitude and frequency size, by adjustable alternating-current voltage source voltage-regulation knob and adjustable alternating-current voltage source frequency Rate adjusting knob is adjusted, and the sinusoidal signal voltage amplitude exported by adjustable alternating-current voltage source and frequency regulation are suitable；Pass through The voltage amplification factor of operational amplifier one is regulated properly by the size changing adjustable feedback resistance and adjustable input resistance, passes through The waveform of bridge output voltage after digital oscilloscope will amplify shows, is observed by digital oscilloscope display screen after amplifying The waveform of bridge output voltage, carefully adjust fixture one and the position of fixture two further along column, make bridge output voltage Being zero, now moving armature is positioned at iron core one and the middle of iron core two；

Step 3, electromagnet apparatus is made to work by electromagnet apparatus switch key, by magneticaction in iron block to square Tee section beams of metal applies pulling force, and it is big to measure pulling force suffered by the beams of metal of display screen observation square-section by force-sensing sensor Little, by the operating current of regulating magnet device operating current adjusting knob regulating magnet device, make pulling force size to fit, Then electromagnet apparatus is made to quit work by electromagnet apparatus switch key, so that square-section beams of metal and copper framework, The beams of metal spring oscillator that moving armature, iron block are constituted starts to do simple harmonic oscillation, and when moving armature moves up and down, air gap is changed, Therefore the change of the inductance value of inductance coil one and inductance coil two generating period therewith, and one increase and one subtract, so that electric bridge Output voltage the most periodically changes；

Step 4, this periodically variable bridge output voltage are after operational amplifier one amplifies, then through slow as output Rushing operational amplifier two output of device, waveform shows on digital oscilloscope, observes and put on digital oscilloscope display screen The waveform of the bridge output voltage after great, measures its cycle T, i.e. square-section beams of metal and copper framework, moving armature, iron block structure The beams of metal spring oscillator become does the cycle T of simple harmonic oscillation；

Step 5, treat beams of metal spring oscillator stop vibration, measure gross mass m of copper framework, moving armature, iron block, i.e. Quality m of beams of metal spring oscillator beams of metal midpoint hanging object；

Step 6, measure the effective length of square-section beams of metal with meter ruler, namely lay on two columns of this beam Distance l in the middle of two edges of a knife of end, measures the width b and height d of beams of metal square-section, square-section with slide gauge；

Step 7, by length l of square-section beams of metal, width b, highly d, quality m of beams of metal midpoint hanging object, And the cycle T that beams of metal spring oscillator is when doing simple harmonic oscillation substitutes into formulaThe poplar of beams of metal material can be obtained Family name's modulus Y.

Theoretical basis by the beam deflection method survey Young's modulus of simple harmonic oscillation:

If the square-section beams of metal that an a length of l, width are b, height is d, when its two ends freely ride upon a pair On the parallel horizontal edge of a knife, when midpoint is by downward pulling force F effect, beam will be bent downwardly, if sag curved under beam midpoint is H, if the Young's modulus of beams of metal material is Y, if disregarding the weight of beam, and bending in elastic limit, as h ＜ ＜ l, having

$h=\frac{l^{3}F}{4d^{3}bY}---\left(1\right)$

(1) formula is become

$F=\frac{4d^{3}bY}{l^3}\·h---\left(2\right)$

According to (2) formula as, this square-section beams of metal can be regarded a coefficient of elasticitySpring.At this Square-section beams of metal midpoint hangs the object that a mass is m, then beams of metal spring and this object constitute a beams of metal spring Oscillator, applies certain pulling force to this system, then discharges, then in the vertical direction is done simple harmonic oscillation by object, and its cycle can be by The Period Formula of spring oscillator is obtained, i.e.

$T=2\mathrm{\π}\sqrt{\frac{m}{k}}---\left(3\right)$

Coefficient of elasticity by beams of metal spring(3) formula of substitution, can do simple harmonic quantity and shakes by this beams of metal spring oscillator Cycle time dynamic

$T=\mathrm{\π}\sqrt{\frac{l^{3}m}{d^{3}bY}}---\left(4\right)$

According to (4) formula, Young's modulus Y of beams of metal material can be obtained, i.e.

$Y=\frac{{\mathrm{\π}}^2{l}^{3}m}{d^3{\mathrm{bT}}^2}---\left(5\right)$

According to (5) formula, as long as measuring length l of square-section beams of metal, width b, highly d, beams of metal spring vibration interest Belong to quality m of beam midpoint hanging object, and cycle T when beams of metal spring oscillator does simple harmonic oscillation, it is possible to substitute into formula Obtain Young's modulus Y of beams of metal material.

The invention has the beneficial effects as follows:

One, the present invention proposes a kind of new method surveying Young's modulus by the beam deflection method of simple harmonic oscillation, the method with The beam deflection method generally used in Physical Experiments is surveyed the method for metal material Young's modulus and be there is essence difference, and The experimental principle of the method institute foundation is the simplest, it is simply that common mass-spring model, just has been directed in high school physics class Correlation formula, also has detailed analysis, is easily understood in course of University Physics.If it is real that therefore this invention is incorporated into College Physics Test in class, be remarkably contributing to abundant Experiment of College Physics content, the thinking of open student, the initiative spirit of training student, strengthen Student uses knowledge problem-solving ability flexibly.

Its two, it is the most uncomplicated that what the present invention proposed surveys the experimental provision of Young's modulus by the beam deflection method of simple harmonic oscillation, Improve a little on the basis of existing experimental provision, be easier to realize.

Its three, beams of metal spring oscillator is done the cycle T of simple harmonic oscillation by the experimental provision that the present invention proposes, and passes through inductance value Change be converted to the cycle T of periodically variable bridge output voltage, after amplified device amplifies, waveform is at digital oscilloscope On show, observing the waveform of bridge output voltage, measure its cycle T, experimental phenomena is directly perceived, observes and measures the side of comparison Just.

Its four, the experimental provision that the present invention proposes uses electromagnet apparatus to make square-section beams of metal and copper framework, activity The beams of metal spring oscillator that armature, iron block are constituted does simple harmonic oscillation, easy to operate.

Its five, the experimental provision that the present invention proposes measures pulling force suffered by square-section beams of metal by force-sensing sensor big Little, and shown by force-sensing sensor measurement display screen, can conveniently monitor pulling force suffered by beams of metal, it is to avoid exceed elastic limit Degree.

Accompanying drawing explanation

The present invention is further described with embodiment below in conjunction with the accompanying drawings.

Fig. 1 is the structural representation one of the present invention.

Fig. 2 is the structural representation two of the present invention.

1. pedestal in figure, 2. pedestal level gauge, 3. pedestal leveling serew, 4. column, 5. the column edge of a knife, 6. square-section gold Belong to beam, 7. copper framework, 8. the copper framework edge of a knife, 9. force-sensing sensor, 10. moving armature, 11. electromagnet apparatus, 12. electric magnet dresses Put operating current adjusting knob, 13. electromagnet apparatus switch keys, 14. force-sensing sensor Mersure Controlers, the 15. quick sensings of power Device measurement display screen, 16. zeroing knobs, 17. measurement startup buttons, 18. iron blocks, 19. inductance coils one, 20. inductance coils two, 21. iron cores one, 22. iron cores two, 23. attachment means, 24. fixtures one, 25. fixtures two, 26. adjustable resistances one, 27. adjustable resistances Two, 28. adjustable alternating-current voltage sources, 29. adjustable alternating-current voltage source display screens, 30. adjustable alternating-current voltage source voltage-regulation knobs, 31. adjustable alternating voltage source frequency adjusting knobs, 32. adjustable alternating-current voltage source function switching keys, 33. adjustable feedback resistance, 34. operational amplifiers one, 35. adjustable input resistances, 36. operational amplifiers two, 37. digital oscilloscopes, 38. digital oscilloscopes show Display screen, 39. digital oscilloscope switch keys.

Detailed description of the invention

In figure, pedestal 1 arranges two columns 4, each two column 4 upper ends fix the steel edge of a knife, i.e. a column The edge of a knife 5, the blade of two edges of a knife is parallel to each other, and square-section beams of metal 6 two ends freely ride upon the cutter of two column 4 upper ends On mouth, overlapping a copper framework 7 on square-section beams of metal 6, copper framework 7 and square-section beams of metal 6 contact position are also one The edge of a knife, i.e. the copper framework edge of a knife 8, and the copper framework edge of a knife 8 is located exactly at the edge of a knife middle of two column upper ends, at copper framework 7 Lower end arranges force-sensing sensor 9, and force-sensing sensor 9 is connected with a moving armature 10 by attachment means, and moving armature 10 passes through Attachment means is connected with an iron block 18, arranges electromagnet apparatus 11 below iron block 18.Force-sensing sensor 9 is by interface and the quick biography of power Sensor Mersure Controler 14 is connected, and force-sensing sensor 9 is used for measuring pulling force size suffered by copper framework 7, namely square-section gold Belong to pulling force size suffered by beam 6 midpoint, and can be shown by force-sensing sensor measurement display screen 15.Electromagnet apparatus 11 is used Apply pulling force to square-section beams of metal 6 by magneticaction in iron block 18, then discharge, so that copper framework 7, movable rank Ferrum 10, iron block 18 do simple harmonic oscillation under square-section beams of metal 6 acts on, and can be by the regulation rotation of electromagnet apparatus operating current Button 12 regulates pulling force size.Two i.e. iron cores 1 of the identical iron core of specification and iron core 2 22 are separately positioned on two fixtures I.e. on fixture 1 and fixture 2 25, fixture 1 and fixture 2 25 are arranged on column 4, and fixture 1 and fixture 2 25 can edges Column 4 moves to change position, two i.e. inductance coils 1 of the identical inductance coil of specification and inductance coil 2 20 points It is not wound on iron core 1 and iron core 2 22.Two i.e. inductance coils 1 of inductance coil, inductance coil 2 20 and two are adjustable Resistance i.e. adjustable resistance 1, adjustable resistance 2 27 collectively form a differential bridge.Electric bridge is given by adjustable alternating-current voltage source 28 Thering is provided power supply, sinusoidal signal voltage amplitude and the frequency size of the output of adjustable alternating-current voltage source 28 can be respectively by adjustable exchanges Voltage source voltage-regulation knob 30 and adjustable alternating voltage source frequency adjusting knob 31 are adjusted, and can be at adjustable alternating voltage Show on source display screen 29.The outfan concatenation operation amplifier 1 of electric bridge, operational amplifier 1 is anti-as one To voltage amplifier, voltage amplification factor can be carried out by the size changing adjustable feedback resistance 33 and adjustable input resistance 35 Regulation, amplifies the output voltage of electric bridge, then exports through the operational amplifier 2 36 as output buffer, operational amplifier two 36 are connected with digital oscilloscope 37 by interface, and the waveform of the bridge output voltage after amplifying can be shown by digital oscilloscope 37 Out, observe and measure.

Specific experiment operating procedure is:

(1) by observing pedestal level gauge 2, adjust the pedestal leveling serew 3 on pedestal 1, make square-section beams of metal 6 water Flat.

(2) along column 4 movable clamp 1 and fixture 2 25, moving armature 10 is made to be positioned in iron core 1 and iron core 2 22 Between, by adjustable alternating-current voltage source function switching key 32, adjustable alternating-current voltage source display screen 29 shows adjustable friendship respectively The sinusoidal signal voltage amplitude of stream voltage source 28 output and frequency size, by adjustable alternating-current voltage source voltage-regulation knob 30 and Adjustable alternating voltage source frequency adjusting knob 31 is adjusted, the sinusoidal signal voltage amplitude exported by adjustable alternating-current voltage source 28 And frequency regulation is suitable.By changing the size of adjustable feedback resistance 33 and adjustable input resistance 35 by operational amplifier 1 Voltage amplification factor regulation is suitable, and the waveform of the bridge output voltage after being amplified by digital oscilloscope 37 is shown.Logical Cross digital oscilloscope display screen 38 and observe the waveform of the bridge output voltage after amplifying, carefully adjust fixture along column 4 further One 24 and the position of fixture 2 25, making bridge output voltage is zero, and now moving armature 10 is positioned at iron core 1 and iron core 2 22 Middle.

(3) make electromagnet apparatus 11 work by electromagnet apparatus switch key 13, given in iron block 18 by magneticaction Square-section beams of metal 6 applies pulling force, and observes 6 tensions of square-section beams of metal by force-sensing sensor measurement display screen 14 Power size, by the operating current of regulating magnet device operating current adjusting knob 12 regulating magnet device 11, makes pulling force Size to fit, then makes electromagnet apparatus 11 quit work, so that square-section is golden by electromagnet apparatus switch key 13 Belong to beam 6 to start to do simple harmonic oscillation with copper framework 7, moving armature 10, the beams of metal spring oscillator of iron block 18 composition.Moving armature 10 When moving up and down, air gap is changed, therefore the change of the inductance value of inductance coil 1 and inductance coil 2 20 generating period therewith Change, and an increasing one subtracts, so that bridge output voltage the most periodically changes.

(4) this periodically variable bridge output voltage is after operational amplifier 1 amplifies, then through as output buffering Operational amplifier 2 36 output of device, waveform shows on digital oscilloscope 37, sees on digital oscilloscope display screen 38 Examine the waveform of the bridge output voltage after amplification, measure its cycle T, i.e. square-section beams of metal 6 and copper framework 7, moving armature 10, the beams of metal spring oscillator that iron block 18 is constituted does the cycle T of simple harmonic oscillation.

(5) treat that beams of metal spring oscillator stops vibration, measure copper framework 7, moving armature 10, gross mass m of iron block 18, i.e. Quality m of beams of metal spring oscillator beams of metal midpoint hanging object.

(6) measure the effective length of square-section beams of metal 6 with meter ruler, namely lay two column 4 upper ends of this beam Two distances l in the middle of the edges of a knife, measure the width b and height d of square-section beams of metal 6 square-section with slide gauge.

(7) by length l of square-section beams of metal 6, width b, highly d, quality m of beams of metal midpoint hanging object, with And the cycle T that beams of metal spring oscillator is when doing simple harmonic oscillation substitutes into formulaThe Young of beams of metal material can be obtained Modulus Y.

Above the present invention is set forth, but the most conditional intention of embodiment that the present invention is introduced, not Deviating from the range of present subject matter, the present invention can have multiple changing and modifications.

Claims (2)

1. survey the experimental provision of Young's modulus by the beam deflection method of simple harmonic oscillation, it is characterised in that it is included on pedestal setting Two columns, each two column upper ends fix a steel edge of a knife, and the blade of two edges of a knife is parallel to each other, a square-section metal Beam two ends freely ride upon on the edge of a knife of two column upper ends, overlap a copper framework, copper framework on the beams of metal of square-section Also it is an edge of a knife with beams of metal contact position, square-section, and the copper framework edge of a knife is just being located exactly at the edge of a knife of two column upper ends Centre, arranges force-sensing sensor in copper framework lower end, and force-sensing sensor is connected with a moving armature by attachment means, movable rank Tie Tong crosses attachment means and is connected with an iron block, arranges electromagnet apparatus below iron block；Force-sensing sensor is by interface and the quick biography of power Sensor Mersure Controler is connected, and force-sensing sensor is used for measuring pulling force size, namely square-section beams of metal suffered by copper framework Pulling force size suffered by midpoint, and can be shown by force-sensing sensor measurement display screen；Electromagnet apparatus is used for passing through magnetic Power acts on iron block and applies pulling force to square-section beams of metal, then discharges, so that copper framework, moving armature, iron block are at square Do simple harmonic oscillation under tee section beams of metal effect, and pulling force size can be regulated by electromagnet apparatus operating current adjusting knob；

Two identical iron cores of specification are separately positioned on two fixtures, and fixture is arranged on column, and fixture can be along column Mobile to change position, two identical inductance coils of specification rotating around on two iron cores, two inductance coils and two Adjustable resistance collectively forms a differential bridge, adjustable alternating-current voltage source provide power supply, adjustable alternating-current voltage source to electric bridge Sinusoidal signal voltage amplitude and the frequency size of output can be adjusted by knob, and can show at adjustable alternating-current voltage source Screen display is out；The outfan concatenation operation amplifier one of electric bridge, as a backward voltage amplifier, voltage amplification factor Can be adjusted by the size changing adjustable feedback resistance and adjustable input resistance, the output voltage of electric bridge is amplified, then Exporting through the operational amplifier two as output buffer, operational amplifier two is connected with digital oscilloscope by interface, numeral The waveform of the bridge output voltage after amplifying can be shown by oscillograph, observes and measures.

The beam deflection method of simple harmonic oscillation the most according to claim 1 is surveyed the experimental provision of Young's modulus and is surveyed metal Young mould The experimental technique of amount, it is characterised in that the detailed process of the method comprises the following steps:

Step one, by observing pedestal level gauge, adjust the pedestal leveling serew on pedestal, make square-section beams of metal level；

Step 2, along column movable clamp one and fixture two, make moving armature be positioned in the middle of iron core one and iron core two, by adjustable Alternating-current voltage source function switching key, shows that on adjustable alternating-current voltage source display screen adjustable alternating-current voltage source is just exporting respectively String signal voltage amplitude and frequency size, adjusted by adjustable alternating-current voltage source voltage-regulation knob and adjustable alternating voltage source frequency Joint knob is adjusted, and the sinusoidal signal voltage amplitude exported by adjustable alternating-current voltage source and frequency regulation are suitable；By changing It is suitable, by numeral that the voltage amplification factor of operational amplifier one is regulated by the size of adjustable feedback resistance and adjustable input resistance The waveform of bridge output voltage after oscillograph will amplify shows, observes the electricity after amplifying by digital oscilloscope display screen The waveform of bridge output voltage, carefully adjusts fixture one and the position of fixture two further along column, and making bridge output voltage is zero, Now moving armature is positioned at iron core one and the middle of iron core two；

Step 3, make electromagnet apparatus work by electromagnet apparatus switch key, cut to rectangle in iron block by magneticaction Face beams of metal applies pulling force, and measures pulling force size suffered by the beams of metal of display screen observation square-section by force-sensing sensor, logical Overregulate the operating current of electromagnet apparatus operating current adjusting knob regulating magnet device, make pulling force size to fit, then Electromagnet apparatus is made to quit work by electromagnet apparatus switch key, so that square-section beams of metal and copper framework, activity The beams of metal spring oscillator that armature, iron block are constituted starts to do simple harmonic oscillation, and when moving armature moves up and down, air gap is changed, therefore The change of the inductance value of inductance coil one and inductance coil two generating period therewith, and one increase and one subtract, so that electric bridge output Voltage the most periodically changes；

Step 4, this periodically variable bridge output voltage are after operational amplifier one amplifies, then through as output buffer Operational amplifier two export, waveform shows on digital oscilloscope, on digital oscilloscope display screen observe amplify after The waveform of bridge output voltage, measure its cycle T, i.e. square-section beams of metal and constitute with copper framework, moving armature, iron block Beams of metal spring oscillator does the cycle T of simple harmonic oscillation；

Step 5, treat beams of metal spring oscillator stop vibration, measure gross mass m of copper framework, moving armature, iron block, i.e. metal Quality m of beam spring oscillator beams of metal midpoint hanging object；

Step 6, measure the effective length of square-section beams of metal with meter ruler, namely lay two column upper ends of this beam Distance l in the middle of two edges of a knife, measures the width b and height d of beams of metal square-section, square-section with slide gauge；

Step 7, by length l of square-section beams of metal, width b, highly d, quality m of beams of metal midpoint hanging object, and Cycle T when beams of metal spring oscillator does simple harmonic oscillation substitutes into formulaThe Young mould of beams of metal material can be obtained Amount Y.