CN110940600A - Device and method for automatically measuring elongation at break of plastic - Google Patents
Device and method for automatically measuring elongation at break of plastic Download PDFInfo
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- CN110940600A CN110940600A CN201811106513.5A CN201811106513A CN110940600A CN 110940600 A CN110940600 A CN 110940600A CN 201811106513 A CN201811106513 A CN 201811106513A CN 110940600 A CN110940600 A CN 110940600A
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- G01N3/28—Investigating ductility, e.g. suitability of sheet metal for deep-drawing or spinning
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
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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
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- G01N3/066—Special adaptations of indicating or recording means with electrical indicating or recording means
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- G—PHYSICS
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
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- G01N2203/0617—Electrical or magnetic indicating, recording or sensing means
- G01N2203/0635—Electrical or magnetic indicating, recording or sensing means using magnetic properties
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- G—PHYSICS
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- 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
- G01N2203/067—Parameter measured for estimating the property
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Abstract
An automatic measure plastics elongation at break's device which characterized in that: the clamp comprises a clamp component, a clamping component and a clamping component, wherein the clamp component is provided with a fixed clamping end and a movable clamping end; the detection probe can generate electromagnetic induction with the paint on the plastic tensile standard sample strip and comprises a first detection probe and a second detection probe, and the detection probes are flush with the initial positions of the corresponding marked lines; and the detection circuit is used for recording induction signals generated by corresponding marked lines acquired by the detection probe in the process of tensile test and recording the total time from the initial tensile moment to the breaking moment of the plastic tensile standard sample strip. The invention has the advantages that: the whole process is automatically detected, analyzed and calculated by a computer, the efficiency is high, and the cost is saved; the problem that the gap cannot be spliced due to the loss of materials at the position of the rear fracture opening of part of the plastic is solved; and errors caused by artificial judgment and measurement are avoided.
Description
Technical Field
The invention relates to a device and a method for testing the elongation at break of plastic.
Background
The elongation at break of the plastic is a characteristic parameter of the toughness of the material, and the brittleness or the toughness of one material can be preliminarily judged, so that the plastic can be applied to parts with different requirements.
The elongation at break of a plastic is in particular the ratio of the value of the displacement of the specimen at tensile break to the original length, usually expressed in percent (%). In the plastic tensile test of national standard GBT 1040.1-2006, the elongation at break of the plastic refers to the percentage of the length increment of the effective marked line part when the effective marked line part is pulled apart after the plastic is stretched according to the standard. For example, in a dumbbell-shaped tensile test sample bar, two marked lines are formed at a distance of 50mm from the middle part of the sampling bar, the distance between the two marked lines after the tensile test is measured, and the percentage of increase in the distance is calculated to be the elongation at break.
The existing test of the elongation at break of plastics is mainly realized by a manual test method, namely, two parts broken after the plastics are stretched are spliced together, then the length after stretching is measured manually, and the percentage of the final stretched increased length to the original length is the elongation at break. However, the current method for manually measuring the elongation at break of the plastic has the following disadvantages:
1. the testing process is purely manual measurement, and the testing efficiency is low.
2. For fiber reinforced plastics, because the material is brittle, the material may splash and lose at the fracture, so that the notch splicing cannot be completed.
3. The test process depends on artificial experience judgment, the stability of the measurement result is difficult to guarantee, and the accuracy of the final measurement result is poor due to the influence of the measurement precision of the measurement tool.
In summary, further improvements are needed to address the current situation and problems with existing measurements.
Disclosure of Invention
The first technical problem to be solved by the present invention is to provide a device capable of automatically measuring the elongation at break of plastic with high accuracy of the measurement result, aiming at the above-mentioned current state of the art.
The invention also aims to provide a method for automatically measuring the elongation at break of the plastic by adopting the device.
The technical scheme adopted by the invention for solving the first technical problem is as follows: an automatic measure plastics elongation at break's device which characterized in that: the device comprises
The clamp assembly is used for clamping two ends of a plastic tensile standard sample strip to be measured and comprises a fixed clamping end and a movable clamping end, wherein the plastic tensile standard sample strip is coated with a coating which can generate an electromagnetic effect after being electrified, and the coating comprises a first marking and a second marking which are arranged at an initial interval distance L;
the detection probe can generate electromagnetic induction with the paint on the plastic tensile standard sample strip, the detection probe comprises a first detection probe and a second detection probe which are fixedly arranged on the same side of the clamp assembly, the first detection probe is flush with the initial position of the first marking, and the second detection probe is flush with the initial position of the second marking;
and the detection circuit is used for recording induction signals generated by corresponding marked lines acquired by the detection probe in the process of tensile test and recording the total time from the initial tensile moment to the breaking moment of the plastic tensile standard sample strip.
Preferably, the first detection probe and the second detection probe are respectively provided with an electromagnetic induction coil therein.
Preferably, the first marked line and the second marked line are respectively made of conductive paint, and correspondingly, the first detection probe and the second detection probe are both eddy current sensors.
As a further preference, the conductive paint may preferably be a conductive polymer material.
Preferably, the conductive polymer material may be polyaniline, polypyrrole, or polythiophene.
Preferably, the first marking and the second marking are respectively made of magnetic paint, and correspondingly, the first detection probe and the second detection probe are both magnetic flux sensors.
Preferably, the magnetic paint can be ferroferric oxide.
In order to improve the detection precision and ensure the continuity of signal acquisition, preferably, the first marked line and the second marked line are respectively and uniformly distributed continuously, and the width range of the first marked line and the second marked line is 1-2 mm.
In order to further improve the reliability of detection, preferably, the first reticle and the second reticle are respectively and continuously and uniformly distributed, and the thickness of the first reticle and the thickness of the second reticle are in a range of 200-1000 um.
Preferably, the first and second markings are respectively marked on the middle parallel portion of the plastic tensile standard bar in consideration of the effective portion where the breakage occurs after the tensile is concentrated on the middle portion, and the first and second markings are initially spaced apart by a distance of 40cm < L <60 cm. The proper initial spacing distance can ensure that the fracture position after stretching is just between the first marked line and the second marked line, and if the initial spacing is too small, the fracture position of the sample strip is easy to fall outside the marked lines, so that an accurate measurement value cannot be obtained; if the initial spacing is too large, the ineffective stretch length is easily calculated and an accurate measurement result cannot be obtained, and preferably, L is 50cm as an optimal spacing.
Preferably, the first detection probe is positioned in a normal direction of the first reticle and aligned with a width center position of the first reticle, and a distance between the first detection probe and the first reticle is 1 to 2 mm.
Preferably, the second detection probe is positioned in a normal direction of the second reticle and aligned with a width center position of the second reticle, and a distance between the second detection probe and the second reticle is 1 to 2 mm.
For convenience of operation, preferably, the fixed clamping end and the movable clamping end of the clamp assembly are respectively provided with a clamping screw rod with adjustable tightness.
The detection circuit can be realized by various existing circuits, and preferably, the detection circuit can simply comprise the following functional modules
The high-frequency current oscillator acts on the first marking and the second marking of the plastic tensile standard spline and can generate a magnetic field with high-frequency change;
the signal processing circuit is used for carrying out detection filtering processing on the oscillation voltage signal detected by the detection probe;
the signal amplification circuit is used for carrying out signal amplification processing on the oscillating voltage signal;
the linear correction and transmission circuit is used for carrying out linear compensation on the amplified oscillation voltage signal and converting the oscillation voltage signal into a current signal, and the current signal is fed back to the main control computer;
the timing circuit is used for recording the total time from the initial stretching moment to the breaking moment of the plastic stretching standard sample strip;
and the power supply circuit is used for respectively providing power for the high-frequency current oscillator and the timing circuit, and the power supply circuit is directly controlled to be started and closed by the main control computer.
The technical scheme adopted by the invention for solving the other technical problem is as follows: a method for automatically measuring the elongation at break of plastic is characterized in that a movable clamping end close to a clamp assembly is set as a first marking, a fixed clamping end close to the clamp assembly is set as a second marking, a first detection probe correspondingly detects an induction signal of the first marking, and a second detection probe correspondingly detects an induction signal of the second marking; the method comprises the following steps:
(1) clamping one end of the plastic tensile standard sample strip on the movable clamping end of the clamp assembly, and loosening the other end of the plastic tensile standard sample strip from the fixed clamping end of the clamp assembly;
(2) the movable clamping end moves linearly at a constant stretching speed V, the first detection probe and the second detection probe acquire electromagnetic induction signals, the main control computer records two curves of the electromagnetic induction signals along with the change of time T, and the curves are set as a comparison curve A1 measured by the first detection probe and a comparison curve A2 measured by the second detection probe respectively;
(3) converting two contrast curves A1 and A2 of electromagnetic induction signals changing along with time T into two curves B1 and B2 of electromagnetic induction signals changing along with a stretching distance S, wherein the stretching distance S is stretching speed V multiplied by time T;
(4) the clamp assembly returns to the original position, and two ends of the plastic tensile standard sample strip are respectively clamped on the corresponding movable clamping end and the fixed clamping end;
(5) the movable clamping end moves linearly at a constant stretching speed V, the first detection probe and the second detection probe acquire electromagnetic induction signals, the main control computer records curves of the two electromagnetic induction signals along with the change of time T, and the curves are respectively set as a real-time detection curve C1 measured by the first detection probe and a real-time detection curve C2 measured by the second detection probe;
(6) converting the real-time detection curves C1 and C2 into curves D1 and D2 which change with time T at the stretching distance S through the curves B1 and B2 obtained in the step (3);
(7) performing first derivation on the curve D1 to obtain a derived curve E1, and recording the time t corresponding to the last point of the continuous part in the curve E1, wherein the time t is the breaking time point of the plastic tensile standard sample strip;
(8) substituting the time t into the curves D1 and D2 to obtain the maximum stretching distances S1 and S2 of the curves D1 and D2 at the corresponding time t;
(9) and calculating the final breaking elongation e of the plastic tensile standard sample strip as follows:
and L is the initial spacing distance between the first marked line and the second marked line.
The drawing speed may be determined depending on the particular plastic material to be drawn, and as a preference, the drawing speed V is preferably in the range of 2mm/min to 100mm/min in general.
Compared with the prior art, the invention has the advantages that: firstly, the automatic detection, analysis and calculation of a computer are carried out in the whole plastic stretching process, and the result of elongation at break can be automatically obtained after stretching and breaking are finished for several seconds, so that the efficiency is high, and the time and labor cost are saved; secondly, all data can be synchronously collected in the plastic stretching process, and the problem that notches cannot be spliced due to the loss of materials at the positions of the later-stage fracture openings of part of plastic in the original manual testing process is solved; moreover, manual participation is not needed, the influence of experience of testers is avoided, the accuracy and repeatability of measurement results are better, and errors caused by manual judgment and measurement factors are avoided.
Drawings
Fig. 1 is a schematic structural diagram of an elongation at break measuring apparatus according to an embodiment of the present invention.
Fig. 2 is a structural diagram of a functional module of a detection circuit according to an embodiment of the present invention.
FIG. 3 is a flowchart of a method for detecting elongation at break according to an embodiment of the present invention.
Detailed Description
The invention is described in further detail below with reference to the accompanying examples.
As shown in fig. 1-3, the embodiment discloses an apparatus for automatically measuring elongation at break of plastic, the apparatus includes a fixture assembly 1, a detection probe and a corresponding detection circuit, wherein the fixture assembly 1 is used for clamping two ends of a plastic tensile standard spline 2 to be measured, the fixture assembly 1 includes a fixed clamping end 11 and a movable clamping end 12, the fixed clamping end 11 and the movable clamping end 12 of the fixture assembly 1 are respectively provided with a clamping screw 13 capable of adjusting tightness, and the clamping is convenient.
The plastic tensile standard sample bar 2 is coated with a coating which can generate an electromagnetic effect after being electrified, and the coating comprises a first marking 3 and a second marking 4 which are arranged with an initial interval distance L; in order to improve the detection precision and reliability and ensure the continuity of signal acquisition, the coating on the same marking line is required to be continuously and uniformly distributed, the phenomena of bottom exposure, falling, cracking and the like are avoided, and the width ranges of the first marking line 3 and the second marking line 4 are required to be 1-2 mm; the thickness ranges of the first marking 3 and the second marking 4 are 200-1000 um;
during the stretching process, the narrowest portion mainly in the middle of the material is elongated, but at the final breaking, not only the middle portion but also portions having somewhat wider points at both ends are somewhat elongated, but the increment of elongation of these non-narrowest portions is not an effective portion for testing the tensile properties of the material, and therefore, considering that the effective portion where breaking occurs after stretching is concentrated in the middle, the first index line 3 and the second index line 4 are respectively marked on the middle parallel portion (middle narrow portion) of the plastic tensile standard spline 2, and the first index line 3 and the second index line 4 are initially spaced apart by a distance. The proper initial spacing distance can ensure that the fracture position after stretching is just between the first marking 3 and the second marking 4, and if the initial spacing is too small, the fracture position of the sample strip is easy to fall outside the marking, so that an accurate measurement value cannot be obtained; if the initial spacing is too large, the ineffective stretch length is easily calculated, and an accurate measurement result cannot be obtained, and L is 50cm as an optimal spacing.
The detection probe can generate electromagnetic induction with the paint on the plastic tensile standard sample strip 2, the detection probe comprises a first detection probe 5 and a second detection probe 6 which are fixedly arranged on the same side of the clamp component 1, and electromagnetic induction coils are respectively arranged in the first detection probe 5 and the second detection probe 6;
the first detection probe 5 is flush with the initial position of the first marking 3, the first detection probe 5 is positioned in the normal direction of the first marking 3 and is aligned with the width center position of the first marking 3, and the distance between the first detection probe 5 and the first marking 3 is 1-2 mm; similarly, the initial positions of the second detection probe 6 and the second reticle 4 are also parallel and level, the second detection probe 6 is located in the normal direction of the second reticle 4 and is aligned with the width center position of the second reticle 4, and the distance between the second detection probe 6 and the second reticle 4 is 1-2 mm.
The coating of the embodiment mainly adopts magnetic paint and conductive paint, when the first marking 3 and the second marking 4 are respectively coated with the conductive paint, correspondingly, the first detection probe 5 and the second detection probe 6 are eddy current sensors, and the conductive paint can be preferably a conductive high polymer material, and can be preferably polyaniline or polypyrrole or polythiophene; when the first and second markings 3, 4 are coated with a magnetic paint, which may preferably be ferroferric oxide, the first and second detection probes 5, 6 are accordingly magnetic flux sensors.
The embodiment is provided with a detection circuit for recording induction signals generated by corresponding marked lines collected by a detection probe in the process of tensile testing, the detection circuit can be realized by adopting various existing circuits, and the detection current can simply comprise the following functional modules of each part:
the high-frequency current oscillator acts on the first marked line 3 and the second marked line 4 of the plastic tensile standard spline 2 and can generate a magnetic field with high-frequency change;
the signal processing circuit is used for carrying out detection filtering processing on the oscillation voltage signal detected by the detection probe;
the signal amplification circuit is used for carrying out signal amplification processing on the oscillation voltage signal;
the linear correction and transmission circuit is used for carrying out linear compensation on the amplified oscillation voltage signal and converting the oscillation voltage signal into a current signal, and the current signal is fed back to the main control computer;
the timing circuit records the total time from the initial stretching moment to the breaking moment of the plastic stretching standard sample strip 2;
and the power supply circuit is used for respectively providing power for the high-frequency current oscillator and the timing circuit, and the power supply circuit is directly controlled to be started and closed by the main control computer.
The working principle of the detection circuit of the embodiment is as follows: the main control computer sends out an instruction for starting a power supply circuit, and the high-frequency current oscillator can generate high-frequency oscillation current so as to generate a high-frequency changing magnetic field, so that the marked line coated with the conductive paint (or the magnetic paint) generates eddy current (or is magnetized), and the high-frequency changing magnetic field is generated; meanwhile, the timing circuit starts timing;
when the distance between the conductive paint (or magnetic paint) and the induction coil in the detection probe is changed, the induction coil in the detection probe generates an oscillating voltage signal which is changed along with the distance, the voltage signal is subjected to detection and filtering processing by a signal processing circuit, then the voltage signal is amplified by a signal amplifying circuit, the amplified voltage signal needs to be subjected to linear compensation by a linear correction and transmission circuit so as to reduce the distortion degree, and is converted into a current signal which has a certain linear relation with eddy current (or magnetic flux density), and the main control computer is used for collecting and recording the signal.
Each functional module in the detection circuit of this embodiment can be implemented by the existing specific circuit diagram, and is not described herein again.
The embodiment also discloses a method for realizing automatic measurement of the elongation at break of the plastic, firstly, a movable clamping end 12 close to the clamp assembly 1 is set as a first marking 3 (with a mark of 1 in the following curve parameter representation), a fixed clamping end 11 close to the clamp assembly 1 is set as a second marking 4 (with a mark of 2 in the following curve parameter representation), a first detection probe 5 is corresponding to detect the induction signal of the first marking 3, and a second detection probe 6 is corresponding to detect the induction signal of the second marking 4;
the method for realizing the automatic measurement of the elongation at break of the plastic comprises the following steps:
(1) one end of the plastic stretched standard spline 2 is clamped to the movable clamping end 12 of the clamp assembly 1, and the other end of the plastic stretched standard spline 2 is released from the fixed clamping end 11 of the clamp assembly 1.
(2) The movable clamping end 12 moves linearly at a constant stretching speed V, the first detection probe 5 and the second detection probe 6 acquire electromagnetic induction signals, the main control computer records two curves of the electromagnetic induction signals along with the change of time T, and the curves are respectively set as a comparison curve A1 measured by the first detection probe 5 and a comparison curve A2 measured by the second detection probe 6; the curve of eddy current I corresponding to time T change is obtained by adopting the conductive paint, and the curve of magnetic flux density B corresponding to time T change is obtained by adopting the magnetic paint.
(3) And converting two comparison curves A1 and A2 of electromagnetic induction signals changing along with time T into two curves B1 and B2 of electromagnetic induction signals changing along with a stretching distance S, wherein the stretching distance S is a stretching speed Vtime T.
(4) And the clamp assembly 1 returns to the original position, and the two ends of the plastic tensile standard sample strip 2 are respectively clamped on the corresponding movable clamping end 12 and the fixed clamping end 11.
(5) The movable clamping end 12 moves linearly at a constant stretching speed V, the first detection probe 5 and the second detection probe 6 acquire electromagnetic induction signals, the main control computer records two curves of the electromagnetic induction signals along with the change of time T, and the curves are respectively set as a real-time detection curve C1 measured by the first detection probe 5 and a real-time detection curve C2 measured by the second detection probe 6; the curve of eddy current I corresponding to time T change is obtained by adopting the conductive paint, and the curve of magnetic flux density B corresponding to time T change is obtained by adopting the magnetic paint.
(6) And (3) converting the real-time detection curves C1 and C2 into curves D1 and D2 which change with time T at the stretching distance S through the curves B1 and B2 obtained in the step (3).
(7) And performing one-time derivation on the curve D1 to obtain a derived curve E1, and recording the time t corresponding to the last point of the continuous part (namely the breakpoint or broken line position of the curve E1) in the curve E1, wherein the time t is the breaking time point of the plastic tensile standard spline 2.
In the process of stretching the plastic standard sample strip 2, the stretching speed is constant, so that the moving speed of the gauge length line is constant; after the plastic is broken, the moving speed of the gauge length line is sharply increased, and sharply reduced and reduced to zero after a short time; the phenomenon is shown in a detection signal-to-time first-order derivative curve E1, namely, obvious break points or disconnection phenomena occur on a curve E1 when the curve is broken; and once the main control computer detects that an obvious breakpoint or disconnection occurs, sending an instruction to close the power supply circuit so as to stop detecting the probe.
(8) And (3) substituting the time t detected in the step (7) into the curves D1 and D2 to obtain the maximum stretching distances S1 and S2 of the curves D1 and D2 at the corresponding time t.
(9) The final elongation at break e of the plastic tensile standard specimen 2 was calculated as:
where L is the initial separation distance of the first reticle 3 and the second reticle 4.
The stretching speed V can be determined according to the specific plastic material to be stretched, and generally, the stretching speed V is preferably in the range of 2mm/min to 100mm/min, such as 2mm/min, 5mm/min, 10mm/min, 20mm/min, 50mm/min, 100mm/min, and the like.
In the embodiment, the automatic detection, analysis and calculation of a computer are carried out in the whole plastic stretching process, and the result of elongation at break can be automatically obtained after stretching and breaking are finished for several seconds, so that the detection efficiency is high; in addition, all data can be synchronously collected in the plastic stretching process, and the problem that gaps cannot be spliced due to the fact that materials at the positions of the later-stage fracture openings of part of the plastic are lost can be solved; the whole process does not need manual participation, so that errors caused by manual judgment and measurement factors are avoided, and the accuracy and repeatability of the measurement result are better.
Claims (16)
1. An automatic measure plastics elongation at break's device which characterized in that: the device comprises
The clamp assembly (1) is used for clamping two ends of a plastic tensile standard spline (2) to be measured, the clamp assembly (1) comprises a fixed clamping end (11) and a movable clamping end (12), wherein the plastic tensile standard spline (2) is coated with a coating capable of generating an electromagnetic effect after being electrified, and the coating comprises a first marking (3) and a second marking (4) which are arranged at an initial interval distance L;
the detection probe can generate electromagnetic induction with the paint on the plastic tensile standard spline (2), the detection probe comprises a first detection probe (5) and a second detection probe (6) which are fixedly arranged on the same side of the clamp assembly (1), the first detection probe (5) is flush with the initial position of the first marking (3), and the second detection probe (6) is flush with the initial position of the second marking (4);
and the detection circuit is used for recording induction signals generated by the corresponding marked lines acquired by the detection probe in the stretching test process, and simultaneously recording the total time from the stretching initial moment to the breaking moment of the plastic stretching standard spline (2).
2. The apparatus for automatically measuring elongation at break of plastic material according to claim 1, wherein: and electromagnetic induction coils are respectively arranged in the first detection probe (5) and the second detection probe (6).
3. The apparatus for automatically measuring elongation at break of plastic material according to claim 1, wherein: the first marked line (3) and the second marked line (4) are respectively made of conductive paint, and correspondingly, the first detection probe (5) and the second detection probe (6) are both eddy current sensors.
4. The apparatus for automatically measuring elongation at break of plastic material according to claim 3, wherein: the conductive paint is a conductive high polymer material.
5. The apparatus for automatically measuring elongation at break of plastic material according to claim 4, wherein: the conductive polymer material is polyaniline, polypyrrole or polythiophene.
6. The apparatus for automatically measuring elongation at break of plastic material according to claim 1, wherein: the first marked line (3) and the second marked line (4) are respectively made of magnetic paint, and correspondingly, the first detection probe (5) and the second detection probe (6) are both magnetic flux sensors.
7. The apparatus for automatically measuring elongation at break of plastic material according to claim 6, wherein: the magnetic paint is ferroferric oxide.
8. The apparatus for automatically measuring elongation at break of plastic material according to claim 1, wherein: the first marked lines (3) and the second marked lines (4) are respectively and uniformly distributed continuously, and the width ranges of the first marked lines (3) and the second marked lines (4) are 1-2 mm.
9. The apparatus for automatically measuring elongation at break of plastic material according to claim 1, wherein: first marking (3) and second marking (4) are continuous evenly distributed respectively, and, the thickness range of first marking (3) and second marking (4) is 200 ~ 1000 um.
10. The apparatus for automatically measuring elongation at break of plastic according to claim (1), wherein: the first and second reticle (3, 4) are marked on the middle parallel portion of the plastic tensile standard spline (2), respectively, and the first and second reticle (3, 4) are initially spaced apart by a distance.
11. The apparatus for automatically measuring elongation at break of plastic material according to claim 1, wherein: the first detection probe (5) is located in the normal direction of the first marking (3) and is aligned with the width center of the first marking (3), and the distance between the first detection probe (5) and the first marking (3) is 1-2 mm.
12. The apparatus for automatically measuring elongation at break of plastic material according to claim 1, wherein: the second detection probe (6) is located in the normal direction of the second reticle (4) and is aligned with the width center of the second reticle (4), and the distance between the second detection probe (6) and the second reticle (4) is 1-2 mm.
13. The apparatus for automatically measuring elongation at break of plastic material according to claim 1, wherein: and a fixed clamping end (11) and a movable clamping end (12) of the clamp assembly (1) are respectively provided with a clamping screw rod (13) with adjustable tightness.
14. The apparatus for automatically measuring elongation at break of plastic material according to claim 1, wherein: the detection circuit comprises
The high-frequency current oscillator acts on the first marked line (3) and the second marked line (4) of the plastic tensile standard spline (2) and can generate a high-frequency changing magnetic field;
the signal processing circuit is used for carrying out detection filtering processing on the oscillation voltage signal detected by the detection probe;
the signal amplification circuit is used for carrying out signal amplification processing on the oscillating voltage signal;
the linear correction and transmission circuit is used for carrying out linear compensation on the amplified oscillation voltage signal and converting the oscillation voltage signal into a current signal, and the current signal is fed back to the main control computer;
the timing circuit records the total time from the stretching initial moment to the breaking moment of the plastic stretching standard sample strip (2);
and the power supply circuit is used for respectively providing power for the high-frequency current oscillator and the timing circuit, and the power supply circuit is directly controlled to be started and closed by the main control computer.
15. A method for automatically measuring the elongation at break of plastics by using the device according to claim 1, wherein the movable clamping end (12) close to the clamp assembly is set as a first marking (3), the fixed clamping end (11) close to the clamp assembly is set as a second marking (4), the first detection probe (5) is used for detecting the sensing signal of the first marking (3), and the second detection probe (6) is used for detecting the sensing signal of the second marking (4); the method comprises the following steps:
(1) clamping one end of the plastic tensile standard spline (2) on a movable clamping end (12) of the clamp assembly, and loosening the other end of the plastic tensile standard spline (2) from a fixed clamping end (11) of the clamp assembly;
(2) the movable clamping end (12) moves linearly at a constant stretching speed V, the first detection probe (5) and the second detection probe (6) acquire electromagnetic induction signals, a main control computer records curves of the two electromagnetic induction signals along with the change of time T, and the curves are set as a comparison curve A1 measured by the first detection probe (5) and a comparison curve A2 measured by the second detection probe (6) respectively;
(3) converting two contrast curves A1 and A2 of electromagnetic induction signals changing along with time T into two curves B1 and B2 of electromagnetic induction signals changing along with a stretching distance S, wherein the stretching distance S is a stretching speed Vtime T;
(4) the clamp assembly returns to the original position, and two ends of the plastic tensile standard sample strip (2) are respectively clamped on the corresponding movable clamping end (12) and the fixed clamping end (11);
(5) the movable clamping end (12) moves linearly at a constant stretching speed V, the first detection probe (5) and the second detection probe (6) acquire electromagnetic induction signals, a main control computer records curves of the two electromagnetic induction signals along with the change of time T, and the curves are respectively set as a real-time detection curve C1 measured by the first detection probe (5) and a real-time detection curve C2 measured by the second detection probe (6);
(6) converting the real-time detection curves C1 and C2 into curves D1 and D2 which change with time T at the stretching distance S through the curves B1 and B2 obtained in the step (3);
(7) performing first derivation on the curve D1 to obtain a derived curve E1, and recording the time t corresponding to the last point of the continuous part in the curve E1, wherein the time t is the breaking time point of the plastic tensile standard spline (2);
(8) substituting the time t into the curves D1 and D2 to obtain the maximum stretching distances S1 and S2 of the curves D1 and D2 at the corresponding time t;
(9) the final elongation at break e of the plastic tensile standard specimen (2) was determined as follows:
wherein L is the initial spacing distance between the first marked line (3) and the second marked line (4).
16. The method for automatically measuring elongation at break of plastic according to claim 15, wherein: the drawing speed V is 2 mm/min-100 mm/min.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114112736A (en) * | 2020-08-28 | 2022-03-01 | 宝山钢铁股份有限公司 | Online measuring device and method for determining fracture elongation of low-carbon steel cold-rolled sheet |
| CN114486516A (en) * | 2021-12-24 | 2022-05-13 | 中国京冶工程技术有限公司 | Method for testing coating crack following performance |
| CN114544359A (en) * | 2022-02-09 | 2022-05-27 | 哈尔滨焊接研究院有限公司 | Method and device for testing strength and plasticity of titanium alloy welding strip |
| CN117168968A (en) * | 2023-10-13 | 2023-12-05 | 江阴济化新材料有限公司 | Performance detection method and device for plastic particle production |
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- 2018-09-21 CN CN201811106513.5A patent/CN110940600A/en active Pending
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114112736A (en) * | 2020-08-28 | 2022-03-01 | 宝山钢铁股份有限公司 | Online measuring device and method for determining fracture elongation of low-carbon steel cold-rolled sheet |
| CN114112736B (en) * | 2020-08-28 | 2023-11-14 | 宝山钢铁股份有限公司 | Online measuring device and method for determining fracture elongation of low-carbon steel cold-rolled sheet |
| CN114486516A (en) * | 2021-12-24 | 2022-05-13 | 中国京冶工程技术有限公司 | Method for testing coating crack following performance |
| CN114544359A (en) * | 2022-02-09 | 2022-05-27 | 哈尔滨焊接研究院有限公司 | Method and device for testing strength and plasticity of titanium alloy welding strip |
| CN117168968A (en) * | 2023-10-13 | 2023-12-05 | 江阴济化新材料有限公司 | Performance detection method and device for plastic particle production |
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