CN112362448A - Dynamic loading test device and method for impact performance of material - Google Patents
Dynamic loading test device and method for impact performance of material Download PDFInfo
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- 238000012360 testing method Methods 0.000 title claims abstract description 37
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- 238000006073 displacement reaction Methods 0.000 claims abstract description 24
- 238000009434 installation Methods 0.000 claims description 13
- 238000009863 impact test Methods 0.000 claims description 8
- 238000010998 test method Methods 0.000 claims description 6
- 239000002184 metal Substances 0.000 claims description 5
- 229910052751 metal Inorganic materials 0.000 claims description 5
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- 239000000523 sample Substances 0.000 description 138
- 238000002474 experimental method Methods 0.000 description 10
- 238000004458 analytical method Methods 0.000 description 4
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/02—Details
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/02—Details
- G01N3/04—Chucks
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/30—Investigating strength properties of solid materials by application of mechanical stress by applying a single impulsive force, e.g. by falling weight
Abstract
The invention discloses a dynamic loading test device and method for impact performance of a material, wherein an impact rod can freely move only in the axial direction of the impact rod; the sample mounting frame is provided with a sample mounting groove and an impact groove, the sample mounting frame is symmetrically provided with two sample mounting grooves which are respectively used for mounting two ends of an impact sample, and the impact groove is used for providing a deformation space for an impact part of the impact sample; one end of the impact rod is an incident end, and the other end of the impact rod is an impact end; after the impact sample is arranged in the sample mounting groove, the impact end is vertical to the back of the impact sample and is tightly attached to the corresponding position of the notch; the incident end is close to the stress wave generation component; the circumferential surface of the impact rod at the axial midpoint is symmetrically provided with strain gauges which are connected with a data acquisition unit. The testing method can obtain the quantitative change rule of the impact energy along with the loading displacement, and can lay a foundation for the research of the dynamic crack propagation mechanism of the pipeline steel body and the welding seam. And the test process is simple and convenient to operate and high in efficiency.
Description
Technical Field
The invention relates to a pipeline steel mechanical property testing technology and an experimental method, in particular to a dynamic loading testing device and a dynamic loading testing method for material impact property.
Background
The pipeline is used as a main mode of energy transmission, the safety of the pipeline is crucial, and the failure accidents of the pipeline often cause serious consequences, such as personal casualties, environmental pollution, economic loss and the like. The safe operation of the pipeline from construction to laying, welding, monitoring and later maintenance is taken as a main index. Compared with the static stable load of the pipeline, the dynamic impact load has a greater threat to the safe operation of the pipeline, because the stress and deformation of the pipeline under the action of the static load are a stable and slow process, and the potential dangerous parts can be discovered through monitoring and detection, so that timely maintenance measures can be taken, and the dynamic load is different, has unpredictability, causes instant large deformation to the pipeline, and often causes the failure of the pipeline in a short time. At present, most pipeline failure accidents are transient failures under the action of dynamic impact loads, such as third-party damage impact, punching and oil stealing impact, rockfall impact, seismic wave impact, debris flow impact and the like. The main test indexes of the related standards such as the current pipe manufacturing standard, the acceptance evaluation standard, the welding process evaluation standard and the like are the quasi-static mechanical properties of the pipe parent metal and the welding line, and the properties cannot reflect the dynamic impact resistance of the pipe. The most obvious example is that the fracture of the failed pipeline often presents a brittle cleavage fracture, the related standards put higher requirements on the toughness of the welding seam and the base metal, and the pipeline failure theoretically presents elastoplastic fracture according to the quasi-static failure condition reasoning, which is not in accordance with the actual case. In fact, the toughness of the material specified by the relevant standards refers to the toughness under the quasi-static condition, and according to the theory of material mechanics, the toughness of the material is reduced and the brittleness is improved along with the increase of the deformation rate, and the material which is tough under the quasi-static loading condition does not necessarily exhibit elastoplastic fracture under the action of dynamic impact load, but due to the lack of a test means based on the strain rate, the strain rate effect of the pipeline cleavage fracture has not been proved through experiments.
The only test index relevant to the dynamic impact performance is the Charpy impact test, but the test only obtains the impact power at a single impact speed, only can show the fracture toughness at the single impact speed, and cannot distinguish the change of energy absorption along with loading time and loading speed, so that the dynamic impact damage mechanism analysis cannot be carried out. Actually, the structure and the material can be subjected to dynamic impact loads at different speeds, the change rule of the impact energy of the material is shown along with the change of the loading speed, and the change of the impact energy along with the expansion of cracks in the fracture process of the structure and the material is the problem which is not solved at present, and the problems are the key for researching the fracture process and the fracture mechanism of the pipeline material.
Disclosure of Invention
In order to solve the problems in the prior art, the invention aims to provide a dynamic loading test device and method for the impact performance of a material.
The technical scheme adopted by the invention is as follows:
a dynamic loading test device for material impact performance is characterized by comprising an experiment table, a strain gauge, a data acquisition unit, a stress wave generation component, an impact rod and a sample mounting frame, wherein the stress wave generation component, the impact rod and the sample mounting frame are arranged on the experiment table; the sample mounting frame is provided with a sample mounting groove and an impact groove, the sample mounting frame is symmetrically provided with two sample mounting grooves, the two sample mounting grooves are respectively used for mounting two ends of an impact sample, and the impact groove is used for providing a deformation space for an impact part of the impact sample; one end of the impact rod is an incident end, and the other end of the impact rod is an impact end; after the impact sample is arranged in the sample mounting groove, the impact end is vertical to the back of the impact sample and is tightly attached to the corresponding position of the notch; the incident end is close to the stress wave generation component; the circumferential surface of the impact rod at the axial midpoint is symmetrically provided with strain gauges which are connected with a data acquisition unit.
Preferably, the impact test specimen is a standard Charpy impact test specimen.
Preferably, the whole shape of the sample mounting rack is a cuboid, one end of the sample mounting rack is a sample loading end, two rectangular open grooves which are perpendicular to each other are formed in the sample loading end from the end surface inwards, the two rectangular open grooves are crossed at the center of the end surface of the sample loading end, one rectangular open groove is used as a sample mounting groove, and the sample mounting groove is perpendicular to the height direction of the end surface of the sample loading end; and the other rectangular open groove is used as an impact groove and is vertical to the height direction of the end surface of the sample loading end.
Preferably, the width dimension of the sample mounting groove is in clearance fit with the thickness of the impact sample, and the depth of the sample mounting groove is larger than or equal to the width of the impact sample.
Preferably, the length of the sample mounting rack is not less than 3 times the width of the impact sample, the width of the sample mounting rack is equal to the length of the impact sample, the height of the sample mounting rack is not less than 3 times the thickness of the impact sample, and the depth of the impact groove is not less than 2 times the width of the impact sample.
Preferably, the impact rod is a cylindrical metal rod, the diameter of the impact rod is larger than the thickness of the impact sample, the diameter of the impact rod is smaller than the width of the impact groove, the length of the impact rod is larger than the width of incident waves emitted by the stress wave generating component, the incident end is a plane perpendicular to the axis of the impact rod, the impact end is a V-shaped wedge, and the arc radius of the V-shaped wedge is the same as the radius of a blade of the pendulum bob of the impact testing machine.
Preferably, the impact rod is symmetrically provided with two strain gauges on the circumferential surface at the axial midpoint thereof.
A dynamic loading test method for impact performance of materials is carried out by adopting the dynamic loading test device for impact performance of materials, and comprises the following steps:
installing an impact sample in a sample installation groove of a sample installation frame, enabling a notch on the impact sample to face the bottom of the sample installation groove, adjusting the position of the impact sample to enable the notch on the impact sample to be located at the center of the length of the sample installation groove, and enabling the edge where the notch is located on the impact sample to be fully attached to the groove bottom of the sample installation groove;
adjusting the impact rod to enable the impact end to be perpendicular to the length direction of the impact sample and to be tightly attached to the corresponding position of the notch on the back of the impact sample;
stress waves are input to the incident end of the impact rod by utilizing the stress wave generating component, and the incident waves and reflected wave signals on the impact rod are recorded by the data acquisition unit through the strain gauge;
calculating the time-varying rule of the speed of an impact point of the impact sample, the time-varying rule of displacement and the time-varying rule of impact power of the sample by utilizing incident wave and reflected wave signals recorded by a data acquisition unit;
by adjusting the amplitude of the incident wave, the deformation speed of the impact point of the sample is changed, and the amplitude of the incident wave is changed, so that a change curve of the impact power of the material along with the displacement of the impact point at different impact speeds is obtained.
Preferably, according to the stress wave propagation theory, the incident wave and the reflected wave signals recorded by the data acquisition unit are used for calculating the speed change rule, the displacement change rule and the sample impact power change rule of the impact point of the impact sample along with time, and the speed change rule, the displacement change rule and the sample impact power change rule along with time are respectively as follows:
V＝C×(εI(t)-εR(t))
wherein V is the speed of the impact point of the impact sample, L is the displacement of the impact sample loading point, K is the impact energy, C is the stress wave velocity of the impact rod, E is the elastic modulus of the impact rod, S is the cross-sectional area of the impact rod, and epsilonI(t) is the incident wave,. epsilonR(t) is the reflected wave, t is time.
Preferably, the change curves of the impact power of the material under different impact speeds along with the displacement of the impact point are drawn in the same graph, and the influence rule of the impact speed on the impact power of the material is contrastively analyzed.
The invention has the following effects:
the dynamic loading test device for the impact performance of the material can conveniently adjust the position between the stress wave generating component and the impact rod and the position between the impact rod and the impact sample arranged on the sample mounting frame by arranging the experiment table; through setting up stress wave generating component can be for the impact bar input stress wave, and can adjust impact parameter, be convenient for study impact power along with the quantitative change law of loading displacement under the different stress waves, provide the experimental data for pipeline material's fracture mechanism analysis. The two sample mounting grooves are symmetrically arranged on the sample mounting frame, and can be used for respectively arranging two ends of an impact sample, so that the position of the impact sample is suitable for impact, and the arranged impact grooves can provide deformation space for the impact part of the impact sample, thereby ensuring that the impact sample can be normally impacted and deformed; the impact rod is symmetrically provided with strain gauges on the circumferential surface of the axial midpoint of the impact rod, incident waves and reflected wave signals on the impact rod can be detected by using the strain gauges, and the incident waves and reflected wave signals detected by the strain gauges on the impact rod can be recorded by the data acquisition unit, so that the later-stage data analysis and processing are facilitated.
The dynamic loading test method for the impact performance of the material is based on the test device, so that the test method can obtain the quantitative change rule of the impact energy along with the loading displacement, and can lay a foundation for the research of the dynamic crack propagation mechanism of the pipeline steel body and the welding seam. And the test process is simple and convenient to operate and high in efficiency.
Drawings
FIG. 1 is an experimental flow of the dynamic loading test method for impact properties of materials according to the present invention;
FIG. 2 is a schematic structural diagram of a standard Charpy impact specimen;
FIG. 3 is a schematic structural view of a sample mount of the present invention;
FIG. 4 is a schematic view of the structure of the impact bar of the present invention;
FIG. 5 is a schematic view of the whole device for dynamic loading test of impact properties of the material.
In the figure: 1. a notch; 2. a buffer end; 3. a sample loading end; 4. a sample mounting groove; 5. an impact groove; 6. an incident end; 7. an impact end; 8. a stress wave generating member; 9. an impact bar; 10. impacting the test sample; 11. a sample mounting rack; 12. a strain gauge; 13. and a data acquisition device.
Detailed Description
The invention is further described below with reference to the figures and examples.
As shown in fig. 5, the dynamic loading testing apparatus for impact performance of material proposed by the present invention comprises: the device comprises a test bed, a strain gauge 12, a data acquisition unit 13, a stress wave generating component 8, an impact rod 9 and a sample mounting rack 11, wherein the stress wave generating component 8, the impact rod 9 and the sample mounting rack 11 are arranged on the test bed, and the impact rod 9 can freely move only in the axial direction; the sample mounting rack 11 is provided with a sample mounting groove 4 and an impact groove 5, the sample mounting rack 11 is symmetrically provided with two sample mounting grooves 4, the two sample mounting grooves 4 are respectively used for mounting two ends of an impact sample 10, and the impact groove 5 is used for providing a deformation space for an impact part of the impact sample 10; one end of the impact rod 9 is an incident end 6, and the other end is an impact end 7; after the impact sample 10 is arranged in the sample mounting groove 4, the impact end 7 is vertical to the back of the impact sample 10 and is tightly attached to the corresponding position of the notch; the incident end 6 is close to the stress wave generation part 8; the circumferential surface of the impact rod 9 at the axial midpoint is symmetrically provided with strain gauges 12, and the strain gauges 12 are connected with a data acquisition unit 13.
As shown in fig. 2, the impact specimen 10 used in the present invention is a standard charpy impact specimen, and the sampling position of the impact specimen 10 can be a pipeline steel body transverse or longitudinal direction, a pipeline steel straight weld transverse or longitudinal direction, a pipeline steel spiral weld transverse or longitudinal direction, and a pipeline steel ring weld transverse or longitudinal direction. It is the sample size that can be specifically designed according to the geometric constraints of the pipeline steel.
As shown in fig. 3, the entire sample mount 11 of the present invention is a rectangular parallelepiped metal block, the length of the sample mount 11 is not less than 3 times the width of the impact sample 10, the width of the sample mount 11 is equal to the length of the impact sample 10, and the height of the sample mount 11 is not less than 3 times the thickness of the impact sample 10. One end of the sample mounting rack 11 is a buffering end 2, and when the sample mounting rack integrally moves due to overlarge impact load, a buffering device such as a spring can be added at the buffering end to reduce the movement of the sample mounting rack and avoid potential safety hazards; the other end is a sample loading end 3. The sample buffer end 2 is a plane. Two rectangular open grooves which are perpendicular to each other are processed on the end face of the sample loading end 3, and the two grooves are intersected in the center of the end face of the sample loading end. One groove is a sample mounting groove 4, the sample mounting groove 4 is perpendicular to the height direction of the end face of the sample loading end 3, and the sample mounting groove 4 is used for fixing an impact sample 10 at an impact end 7 of an impact rod 9; the other groove is an impact groove 5, and the impact groove 5 is perpendicular to the height direction of the end face of the sample loading end 3 and is used for providing a deformation space for an impact part of the impact sample 10. The width dimension of sample mounting groove 4 is clearance fit with the thickness of impact specimen 10, and the degree of depth of sample mounting groove 4 is greater than or equal to the width of impact specimen 10. The width of the impact groove 5 is 40mm, and the depth is not less than 2 times of the width of the impact sample 10.
As shown in FIG. 4, the impact bar 9 proposed by the present invention is a cylindrical metal bar, the diameter of the impact bar 9 is not less than the thickness of the impact sample 10, the diameter of the impact bar 9 is not more than the width of the impact slot 5, and the diameter length of the impact bar 9 is greater than the width of the incident wave. One end of the impact rod 9 is an incident end 6, and the other end is an impact end 7. The incident end 6 is a plane perpendicular to the axis of the impact rod 9, the impact end 7 is a V-shaped wedge head, and the arc radius of the V-shaped end is the same as the blade radius of the pendulum bob of the impact testing machine.
As shown in fig. 1, the present invention further provides a dynamic loading test method for impact performance of a material, comprising the following steps:
Referring to fig. 1, a stress wave generating member 8, an impact bar 9 and a sample mounting bracket 11 are coaxially and sequentially mounted on a laboratory bench in a conventional manner, an incident end 6 of the impact bar 9 is close to the stress wave generating member 8, a sample mounting groove 4 of the sample mounting bracket 11 is close to an impact end 7 of the impact bar 9, and the impact bar 9 is freely movable only in the axial direction thereof. Install an impact specimen 10 in sample mounting bracket 11's sample mounting groove 4, impact specimen 10's breach 1 orientation 4 bottoms of sample mounting groove, adjustment impact specimen 10 position makes impact specimen 10's breach 1 be located the center department of 4 lengths of mounting groove, and the limit at breach 1 place is fully laminated with the tank bottom of sample mounting groove 4 on impact specimen 10. And adjusting the impact rod 9 to ensure that the wedge edge of the impact end 7 is perpendicular to the length direction of the impact sample 10 and is tightly attached to the corresponding position of the notch on the back surface of the impact sample 10.
And 2, pasting the strain gauge.
2 strain gauges 12 are symmetrically stuck on the circumferential surface at the axial midpoint of the impact rod 9 by a conventional method, and leads of the strain gauges 12 are connected to a data acquisition unit 13.
And 3, loading experiments and collecting data.
When the incident wave is transmitted to the contact surface of the impact end 7 and the test sample 10, because of wave impedance mismatch, part of the incident wave is reflected to form a reflected wave in the incident rod, and the other part enters the interior of the impact test sample to provide energy for opening of the notch and crack propagation. The shape and amplitude of the reflected wave is determined by the deformation speed of the sample. The data acquisition unit 13 records the incident wave and the reflected wave signals through the strain gauge 12 adhered to the impact rod.
And 4, processing data.
According to the stress wave propagation theory, the incident wave and the reflected wave signals recorded by the data acquisition unit are utilized, and the speed and the displacement of the impact point of the impact sample and the change rule of the impact power of the sample along with time are calculated through the formula (1), the formula (2) and the formula (3).
V＝C×(εI(t)-εR(t)) (1)
Wherein V is the speed of the impact point of the impact sample, L is the displacement of the impact sample loading point, K is the impact energy, C is the stress wave velocity of the impact rod, E is the elastic modulus of the impact rod, S is the cross-sectional area of the impact rod, and epsilonI(t) is the incident wave,. epsilonR(t) is a reflected wave. The curve of the change of the impact energy with the displacement of the impact point can be drawn in a graph by taking K as the ordinate and L as the abscissa. The change rule of the impact speed, the deflection and the impact energy along with the displacement of the loading point in the whole dynamic impact process is represented by a curve graph, so that a characteristic impact curve of the material is obtained, and the impact mechanical property of the material is analyzed more deeply and finely so as to further know the characteristics of the material.
And 5, impact parameter adjustment.
By increasing the amplitude of the incident wave, the deformation speed of the impact point of the sample can be improved. The amplitude of the incident wave is changed to obtain a change curve of the impact power of the material along with the displacement of an impact point under different impact speeds, the curve is drawn in the same graph, and experimental data can be provided for the fracture mechanism analysis of the pipeline material by comparing and analyzing the influence rule of the impact speed on the impact power of the material.
Examples
This example was tested for the impact work of the heat affected zone of the X80 girth weld.
The impact specimen 10 used in this example was a Charpy impact specimen of the standard specified in GB/T229, having a length of 55mm, a width of 10mm, a thickness of 7.5mm, and a notch 1 having a depth of 2 mm.
The sample mounting frame 11 of this example is a rectangular parallelepiped titanium alloy block having a length of 100mm, a width of 55mm and a height of 60 mm. The height of sample mounting groove 4 of sample mounting bracket 11 is 8mm, and the degree of depth is 10 mm. The width of the impact groove 5 of the sample mounting rack 11 is 40mm, and the depth is 40 mm.
The impact bar 9 of this embodiment is a cylindrical titanium alloy bar having a diameter of 20mm and a length of 2 m. The impact end 7 of the impact rod 9 is a V-shaped wedge head, and the arc radius of the V-shaped end is 2.5 mm.
The stress wave generator proposed in the invention patent with application number CN 103994922 a is used as the stress wave generator used in the present embodiment.
The embodiment also provides an X80 girth weld heat affected zone impact energy experimental method based on the deformation rate, which specifically comprises the following steps:
The method comprises the steps of installing a stress wave generation component 8, an impact rod 9 and a sample installation frame 11 on a laboratory bench in a coaxial sequence according to a conventional method, enabling an incident end 6 of the impact rod 9 to be close to the stress wave generation component 8, enabling a sample installation groove 4 of the sample installation frame 11 to be close to an impact end 7 of the impact rod 9, and enabling the impact rod 9 to freely move only in the axial direction. Install an impact specimen 10 in sample mounting groove 4 of sample mounting bracket 11, the 1 position orientation in breach of impact specimen 10 the position of adjustment impact specimen 10 is in the bottom of sample mounting groove 4, makes breach 1 be located the center department of mounting groove length, and the limit at breach 1 place is fully laminated with the tank bottom of sample mounting groove 4. And adjusting the impact rod 9 to ensure that the wedge edge of the impact end 7 is perpendicular to the length direction of the impact sample 10 and is tightly attached to the corresponding position of the notch 1 on the back of the impact sample 10.
And 2, pasting the strain gauge.
2 strain gauges 12 are symmetrically adhered to the circumferential surface at the axial midpoint of the impact rod 9 by a conventional method, the adhering position of the embodiment is the circumferential surface of the impact rod at a position 1mm away from the incident end, and the lead of the strain gauge 12 is connected to the data acquisition unit 13.
And 3, loading experiments and collecting data.
When the incident wave is transmitted to the contact surface of the impact end 7 and the sample, a part of the incident wave is reflected due to the mismatching of wave impedance, a reflected wave is formed in the incident wave, and the other part enters the inside of the Charpy impact sample 10 to provide energy for the opening of the notch 1 and the crack propagation. The shape and amplitude of the reflected wave is determined by the deformation speed of the sample. The data acquisition unit 13 records the incident wave and the reflected wave signals through the strain gauge 12 adhered to the impact rod 9.
And 4, processing data.
According to the stress wave propagation theory, the speed and displacement of the impact point of the Charpy impact specimen 10 and the time-varying law of the impact energy of the specimen are calculated by using the incident wave and the reflected wave signals recorded by the data acquisition unit 13 through the formulas (1), (2) and (3). The curve of the change of the impact energy with the displacement of the impact point can be drawn in a graph by taking K as the ordinate and L as the abscissa.
And 5, impact parameter adjustment.
By increasing the amplitude of the incident wave, the deformation speed of the impact point of the sample can be improved. The amplitude of the incident wave is changed to obtain a change curve of the impact power of the material along with the displacement of an impact point under different impact speeds, the curve is drawn in the same graph, and experimental data can be provided for the fracture mechanism analysis of the pipeline material by comparing and analyzing the influence rule of the impact speed on the impact power of the material.
In conclusion, the dynamic impact load is generated by utilizing the stress wave, the Charpy impact sample can be loaded by utilizing the stress wave, the quantitative change rule of the impact power along with the loading displacement can be calculated according to the one-dimensional stress wave propagation theory through the incident wave and the reflected wave signals recorded in the incident rod, meanwhile, the loading speed curve of the material to be tested under the action of the stress wave can be calculated, the impact loading speed can be adjusted by adjusting the waveform and the amplitude of the incident wave, and the impact power test experiment under different deformation speeds can be realized. The experimental method provided by the invention can lay a foundation for researching the dynamic crack propagation mechanism of the pipeline steel body and the welding line.
Claims (10)
1. The dynamic loading test device for the impact performance of the material is characterized by comprising a test bench, a strain gauge (12), a data acquisition unit (13), a stress wave generating component (8), an impact rod (9) and a sample mounting rack (11), wherein the stress wave generating component, the impact rod (9) and the sample mounting rack are mounted on the test bench, and the impact rod (9) can freely move only in the axis direction; the sample mounting rack (11) is provided with a sample mounting groove (4) and an impact groove (5), the sample mounting rack (11) is symmetrically provided with two sample mounting grooves (4), the two sample mounting grooves (4) are respectively used for mounting two ends of an impact sample (10), and the impact groove (5) is used for providing a deformation space for an impact part of the impact sample (10); one end of the impact rod (9) is an incident end (6), and the other end is an impact end (7); after the impact sample (10) is arranged in the sample mounting groove (4), the impact end (7) is vertical to the back of the impact sample (10) and is tightly attached to the corresponding position of the notch; the incident end (6) is close to the stress wave generation component (8); the circumferential surface of the impact rod (9) at the axial midpoint is symmetrically provided with strain gauges (12), and the strain gauges (12) are connected with a data acquisition unit (13).
2. A material impact dynamic loading test device according to claim 1, characterized in that the impact test specimen (10) is a standard charpy impact test specimen.
3. The dynamic loading test device for the impact performance of the material as claimed in claim 1, wherein the overall shape of the sample mounting rack (11) is a cuboid, one end of the sample mounting rack (11) is a sample loading end (3), the sample loading end (3) is provided with two rectangular open grooves which are perpendicular to each other and are formed inwards from the end surface, the two rectangular open grooves are intersected at the center of the end surface of the sample loading end (3), one rectangular open groove is used as a sample mounting groove (4), and the sample mounting groove (4) is perpendicular to the height direction of the end surface of the sample loading end (3); and the other rectangular opening groove is used as an impact groove (5) and is vertical to the height direction of the end surface of the sample loading end (3).
4. A material impact performance dynamic loading test device according to claim 3, characterized in that the width dimension of the sample mounting groove (4) is in clearance fit with the thickness of the impact sample (10), and the depth of the sample mounting groove (4) is larger than or equal to the width of the impact sample (10).
5. A material impact performance dynamic loading test device according to claim 3, characterized in that the length of the sample mounting bracket (11) is not less than 3 times the width of the impact sample (10), the width of the sample mounting bracket (11) is equal to the length of the impact sample (10), the height of the sample mounting bracket (11) is not less than 3 times the thickness of the impact sample (10), and the depth of the impact groove (5) is not less than 2 times the width of the impact sample (10).
6. The dynamic loading test device for the impact performance of the material according to claim 1, wherein the impact rod (9) is a cylindrical metal rod, the diameter of the impact rod (9) is larger than the thickness of the impact sample (10), the diameter of the impact rod (9) is smaller than the width of the impact groove (5), the length of the impact rod (9) is larger than the width of an incident wave emitted by the stress wave generating component (8), the incident end (6) is a plane perpendicular to the axis of the impact rod (9), the impact end (7) is a V-shaped wedge head, and the arc radius of the V-shaped wedge head is the same as the blade radius of a pendulum bob of the impact tester.
7. A material impact performance dynamic loading test device according to claim 1, characterized in that the impact rod (9) is symmetrically provided with two strain gauges (12) on the circumferential surface at the axial midpoint thereof.
8. A method for testing dynamic loading of impact performance of materials, which is characterized by being carried out by adopting the device for testing dynamic loading of impact performance of materials as claimed in any one of claims 1 to 7, and comprising the following steps:
installing an impact sample (10) in a sample installation groove (4) of a sample installation frame (11), enabling a notch (1) on the impact sample (10) to face the bottom of the sample installation groove (4), adjusting the position of the impact sample (10), enabling the notch (1) on the impact sample (10) to be located at the center of the length of the sample installation groove (4), and enabling the edge where the notch (1) is located on the impact sample (10) to be fully attached to the bottom of the sample installation groove (4);
adjusting the impact rod (9) to enable the impact end (7) to be perpendicular to the length direction of the impact sample (10) and to be tightly attached to the corresponding position of the notch on the back of the impact sample (10);
stress waves are input to an incident end (6) of the impact rod (9) by using a stress wave generating component (8), and incident waves and reflected wave signals on the impact rod (9) are recorded by a data acquisition unit (13) through a strain gauge;
calculating the time-varying rule of the speed of an impact point of an impact sample, the time-varying rule of displacement and the time-varying rule of sample impact power by utilizing incident wave and reflected wave signals recorded by a data acquisition unit (13);
by adjusting the amplitude of the incident wave, the deformation speed of the impact point of the sample is changed, and the amplitude of the incident wave is changed, so that a change curve of the impact power of the material along with the displacement of the impact point at different impact speeds is obtained.
9. The dynamic loading test method for the impact performance of the material according to claim 8, characterized in that according to the stress wave propagation theory, the incident wave and the reflected wave signals recorded by the data collector (13) are utilized to calculate the time-dependent change rule of the speed of the impact point of the impact sample, the time-dependent change rule of the displacement and the time-dependent change rule of the impact power of the sample, and the time-dependent change rule of the speed, the time-dependent change rule of the displacement and the time-dependent change rule of the impact power of the sample are respectively as follows:
V＝C×(εI(t)-εR(t))
wherein V is the speed of the impact point of the impact sample, L is the displacement of the impact sample loading point, K is the impact energy, C is the stress wave velocity of the impact rod, E is the elastic modulus of the impact rod, S is the cross-sectional area of the impact rod, and epsilonI(t) is the incident wave,. epsilonR(t) is the reflected wave, t is time.
10. The method for dynamically loading and testing the impact performance of the material as claimed in claim 8, wherein the impact power of the material at different impact speeds is plotted along with the change curve of the displacement of the impact point in the same graph, and the impact power of the material is contrastively analyzed according to the impact speed.
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