JPS63113342A - Dynamic characteristic measuring apparatus - Google Patents

Abstract

PURPOSE:To enable subsequent analysis based on a load displacement data, by converting a load signal and a displacement signal into digital data during the breaking of the material to be stored. CONSTITUTION:When a test piece 3 set on an anvil 4 is impacted with a hammer 5, an active gauge 23 causes a change in the resistance and a load signal is outputted from a bridge circuit to be stored into a memory 34 via a load adjustor 33. At the same time, a potentiometer 21 mounted in a rotating shaft of the hammer 5 causes a change in the resistance and a displacement signal is outputted from the bridge circuit to be stored into a memory 36 via a displacement adjustor 35. A data processing is performed with a microcomputer 37 based on a load-displacement data stored in the memories 34 and 36 and moreover, a data processing is performed with a personal computer 38 based on the data and a data stored in an external memory 39 thereby calculating a dynamic characteristic value of the material.

Description

[Detailed Description of the Invention] Object of the Invention (Industrial Application Field) The present invention relates to a dynamic property measuring device, and specifically relates to a dynamic property measuring device,
The present invention relates to an apparatus for measuring dynamic characteristic values of various materials such as synthetic resin materials, inorganic materials, and composite materials through instrumented impact tests such as instrumented Charpy tests.

(Problems to be solved by conventional techniques and inventions) The Charpy impact tester has been popular as a toughness evaluation method for metal materials since ancient times, and has contributed to research on the toughness of metal materials, but it is only an empirical method. was only given. For this reason, attempts have been made to instrument the device so that it can record the load-displacement (referring to the displacement of the impact point; the same applies throughout this specification) curve necessary for the basic evaluation of toughness values. .

As fracture mechanics began to be incorporated into the design of materials, equipment, and structures, evaluation of fracture toughness under impact loads became highly desirable, and the simplest method, the Charpy test, attracted attention. However, in order to effectively evaluate dynamic fracture toughness values using this method, there are major problems such as the test piece dimensions, the interference of vibration waves and stress waves associated with impact, and the criteria for determining the validity of the obtained values. The ASTM (American Society for Testing and Materials) E24 committee has only made the current findings as a screening test method, and furthermore, studies have only been conducted within the range where linear fracture mechanics is established.

Against this background, the present invention was made for the purpose of more actively developing the instrumented impact testing method, and it not only enables the recording of load-displacement curves, but also improves the efficiency of subsequent analysis processing. The purpose of the present invention is to provide a new dynamic property measuring device that can perform a toughness evaluation analysis based on recent elasto-plastic fracture mechanics standards more quickly and accurately.

Structure of the Invention (Means for Solving Problems) Therefore, the present invention provides a storage device that converts the load signal and displacement signal obtained from a 3° single-load impact tester into digital data and stores the respective load and displacement signals at the time of material failure. This constitutes a dynamic property measuring device comprising: and an arithmetic unit that calculates dynamic property values of a material based on the load data and displacement data stored in the storage device.

Examples of the dynamic characteristic values include a dynamic elastic-plastic fracture toughness value Jd, a tearing modulus 'ma1, and the like.

Further, examples of the storage device include a digital memory device using a RAM, an external storage device using a floppy disk device, etc., and examples of the arithmetic device include a microcomputer with a dedicated working memory, a general-purpose personal computer, etc. A computer etc. can be exemplified.

(Function) The storage device converts the load signal and displacement signal at the time of material failure, which completes in a short time, into digital data and stores them, so it enables later analysis based on the load-displacement data. .

The calculation device efficiently analyzes dynamic property values of the material,
Disturbs quickly and accurately.

(Example) An example embodying the present invention will be described below with reference to the drawings.

Since the dynamic property measuring device of this example is connected to a conventionally existing instrumented Charpy testing machine, we will first explain the outline of the instrumented Charpy testing machine, and then explain the present dynamic property measuring device. Let us explain in detail.

[Instrumented Charpy Testing Machine] As shown in FIG. Anvil 4 for supporting the test piece 3 provided at the bottom of the base 2, and an anvil 4 rotatably attached to the upper end of the base 2.
It consists of a hammer 5 etc. attached.

At the top of the base body 2 and at the base of the hammer 5, there are provided a support device @7 that supports the hammer 5 at an arbitrary lifting angle, and a lifting lever 8 and a release lever 9. By changing the speed, the impact speed at which the striking portion 6 of the hammer 5 hits the test piece 3 can be arbitrarily set in the range of 0 to 5.1 m/s.

Furthermore, the anvil 4 is configured so that it can accommodate test pieces 3 of various sizes by replacing its constituent parts.

Roughly, as shown in Fig. 3, the anvil 4 is equipped with a stop block device 11 capable of WIIR for determining the crack initiation point and dynamic elastoplastic fracture toughness value of the material by the stop block test method described later. be done. The stop block device 11 is composed of a test piece 3 mounting part 12, a replaceable block 13 that supports both ends of the test piece 3, a hammer stop part 14 against which the striking part 6 of the hammer 5 hits, and the like.

Therefore, if the same stop block device 11 is used while replacing blocks 13 of various thicknesses, when the test piece 3 is displaced to a predetermined value of 0 to 10 m by the striking part 6 of the hammer 5, the striking part 6 It hits the stop part 14 and is forcibly stopped. By interrupting the displacement of the test piece 3 in this way, the amount of crack growth in the test piece 3 can be changed arbitrarily, and the crack initiation point can be accurately determined. The stop block device 11 is made of high-hardness tool steel, and at least the hammer stop portion 14 is surface-hardened.

The main body 1a of the instrumented Charpy testing machine 1 is instrumented as follows.

The test piece 3 is attached to the rotation axis of the hammer 5 from the rotation angle of the hammer 5.
A film potentiometer 21 for determining the displacement of is attached. The film potentiometer 21 is assembled into a bridge circuit to increase sensitivity and accuracy, and the output of the bridge circuit is connected to a displacement output terminal 22 provided on the base body 2.
It is connected to the.

On the other hand, four semiconductor strain gauges 23 are pasted on the side surface of the striking part 6 of the hammer 5 to determine the load applied to the test piece 3 from the elastic deformation of the striking part 60. Two of these semiconductor strain gauges 23 have their measurement directions affixed in the front-rear direction of the striking part 6 and can be touched as active gauges 23a, and the other two have their measurement directions affixed in the vertical direction of the striking part 6. The dummy gauge 23b is attached to the dummy gauge 23b. Further, these semiconductor strain gauges 23 are also assembled into a bridge circuit, and the output of the bridge circuit is connected to a load output terminal 24 provided on the base body 2.

[Dynamic characteristic measuring device] The dynamic characteristic measuring device 31 of this embodiment includes: (1) a load adjustment device 33 built into a movable rack 32, a load digital memory device 34, a displacement adjustment device 35, a displacement (2) a digital memory device 36 for use in storage, a microcomputer 37 as a first arithmetic device, and (1) a personal computer 3 as a second arithmetic device provided outside the rack 32.
8, an external storage device 39, and (2) an external display device and other attached devices. These will be explained in detail below.

A load adjustment device E33 is connected to the load output terminal 24 via a connection cord 41, and the load adjustment device 33 is equipped with a balance circuit (not shown) that can perform zero point setting and calibration of the load signal. Adjustment device 33 for the same load
A load digital memory device 34 for converting the load signal into digital data and storing it is connected to the output of the load signal. The digital memory device for load between
An AD converter 42 that samples at a cycle that can be arbitrarily set in the range of ~999 μs and minimizes it to 12-bit load data, and a RAM (random access) with a storage capacity of 11,024 words x 10 channels connected to the AD converter 42.・Memory) 43.

Therefore, the digital memory device 34 for the same load is RAM4.
By switching the 3 channels, the load data for the 10 test pieces 3 can be stored in sequence.

On the other hand, a displacement adjustment device 35 is connected to the displacement output terminal 22 via a connection cord 44.
Reference numeral 5 denotes a balance circuit (not shown) that can perform zero point setting and calibration of the displacement signal, and a trigger signal that is generated when the striking part 6 of the hammer 5 approaches the test piece 3, and is connected to the load digital memory device 34 and the next one. It is equipped with a trigger circuit (not shown) that starts the 6th old function of the displacement digital memory device 36. A displacement digital memory device 36 consisting of an AD converter 45 and a RAM 46 similar to the load digital memory device 34 is connected to the displacement adjustment device 35 .

An oscilloscope 47 is connected to the outputs of both adjustment devices 33 and 35, so that it is possible to photograph the load-displacement curve at the time of fracture of the test piece.

Next, the load digital memory device 34 and the displacement digital memory device 36 are connected to a microcomputer 37 as a first arithmetic unit equipped with a CPU and a dedicated working memory, and the microcomputer 37 is connected to the next ViO input. It is programmed to have ■～■.

■Elimination of vibration waves superimposed on the load signal The load signal in the instrumented Charpy test contains a single oscillatory wave that is not related to the true destruction of the material, so it is necessary to eliminate it. This filter is programmed to eliminate vibration waves by using the moving average method, which is superior to conventional analog filters in terms of accuracy and multiple calculations. In this method, the sample value series
In order to eliminate small periodic fluctuations, the sample values are averaged by a constant moving average number m while shifting the order of the values. In other words, the moving average is Y. Then, it is expressed by the following formula.

n+m-1 Y = 1/m-Σ Xk - (1) k=n Cutoff frequency f. is influenced by the sampling frequency f and the number of moving averages m, and is expressed by the following equation.

f = 0.443f /m - (2>S) Therefore, the present microcomputer 37 performs filtering on multiple targets while changing the m value and judging the results each time to avoid excessive correction. It is.

(2) Determination of the maximum load P and yield load P From the thus corrected data, the maximum load PIIl and yield load P are determined by the flow shown in Fig. 4-5.

First, for the maximum load PIIl, search for the maximum value in the load data and save it.

Next, for the yield load ff1Pv, the search is started from the rising point of the second vibration wave, first, the average slope for every '17 word is found, and then the point where the average slope changes suddenly is found. Roughly, the average interval is shortened to 5 words and the same operation is performed, yielding load @
Let it be P. In this way, the reason for starting the data search from the rise of the second vibration wave is when the specimen 3 is improperly placed on the anvil 4, the first vibration wave is This is because the purpose is to ignore this because it appears greatly. In addition, the fourth
A, B, C, D, and X in FIG. 5 are symbols for convenience of explanation.

■Calculation of nominal crack initiation energy Ei and nominal crack propagation energy ED Next, reduce the integral value from the load-displacement data to the maximum load PIIl on the load-displacement curve to obtain the nominal crack initiation energy E. Similarly, an integral calculation program is provided that calculates the integral value after the latest arrival fflPm to obtain the nominal crack propagation energy Ep.

The programming of the microcomputer 37 is as described above.

The microcomputer 37 includes a printing device 48 that prints the maximum load PIIl, yield load P, total nominal crack initiation energy Ei, and nominal crack propagation energy E through an interface (not shown), and a printing device 48 that prints the maximum load PIIl, the yield load P, the total nominal crack initiation energy Ei, and the nominal crack propagation energy E, and the stored load. An oscilloscope 49 that displays a load-displacement curve from displacement data is also connected to an X-Y recorder 50.

Subsequently, a general-purpose personal computer 38 as a second cotton drawing device was connected to the microcomputer 37 and both digital memory devices 34 and 36 via a bit serial interface. The floppy disk device as the external storage device 39 is connected to both digital memories Wi34.
, 36 and the calculation results by the microcomputer 37 can be stored permanently. The same personal computer 38
is programmed to have the following functions (1) to (2), which can be performed in whole or selectively as needed by operating the keyboard 51, and displayed on the CRT display 52 at any time.

■Estimating the crack initiation point using the compliance rate of change method This method will be schematically explained with reference to FIG. As can be seen from the figure, from the elastic compliance Ce determined from the initial elastic line of the load-displacement curve and the compliance C at each arbitrary point, the compliance change rate ΔC/Ce
is defined by the following equation.

ΔC/C=(C-Co>/C8・(3) When the personal computer 38 calculates this:1 compliance change rate ΔC/C for each displacement, the compliance change rate ΔC/C8 Since a sudden turning point appears, this point is detected and the crack initiation point (referred to as the crack propagation starting point. The same applies hereinafter).

).

■Measurement of dynamic elastic-plastic fracture toughness value Jd The J value required for elastic-plastic fracture toughness value can be determined by the following simple formula.

J=2E/B (W-a,) - (4) Here, E is the area under the load-displacement curve (energy), B is the thickness of the test piece, W is the width of the test piece, and a□ is the initial is the crack length. Now, E in the above equation is the energy E absorbed by the specimen 3 up to the point of crack initiation. By substituting -, the dynamic elastic-plastic fracture toughness value Jd can be determined.

Therefore, first, the integral value up to the crack initiation point estimated by the compliance change rate method on the load-displacement curve is calculated, and the apparent crack initiation energy Eo is determined. This value also includes the energy due to elastic deformation of the Charpy tester body 1 (/v), so as shown in FIG. Correct to −.

EQ==EQXC8/C, (5) Here, C5 is the compliance of the test piece, and Ct is the sum of the compliance C8 of the test piece and the compliance Cll1 of the Charpy tester main body 1.

In this way, the internal computer 38 calculates the true crack initiation energy E. ' and then calculates the dynamic elastic-plastic fracture toughness value Jd from equation (4).

Now, when the following equation is satisfied, it is expressed as Jd=Jld as a valid J value under the plane strain condition.

B, ao, W-a□≧25J/σo (6) Here, C0 is the flow stress.

■Analysis of crack propagation resistance curve using key curve method Now, as shown in Fig. 8<a), find the plastic displacement component △, 1 from the rising straight part to each cart point in the load-displacement curve, and Draw a load-plastic displacement component curve as shown in Figure (b). In this load-plastic displacement component Δ, 1 curve, a key curve approximation of the following equation is performed for the range up to the latest arrival fflPm, and constants n and k are determined.

P-W/bo=k(Δp,/W>n-(7) By the way, the crack growth rate Δa at an arbitrary point after crack initiation is predicted by the following equation by modifying the above equation.

Δa=W-((P-W/to-Δ,,n) 1/
2n+1 10ao) ... (8) From equation (8), the crack growth ■△a at pl is determined for each plastic displacement component, and using the J value from the area under the load-displacement curve up to that point, A crack growth resistance curve (also referred to as J-Δa curve or JR curve) is determined.

■Tearing modulus Tll based on crack growth resistance curve
Analysis of 1at Calculate the slope (dJ/da) at each crack growth position of the crack growth resistance curve obtained as above, and calculate the tearing modulus 1las (crack growth resistance) TITlat using the following formula.
bell out.

T = (E/σ0) ・(dJ/da)mar (9) From this, it is possible to draw the maximum Δa curve of tearing modulus "mar' crack growth.

(2) Analysis of tearing modulus Tmat by rebound compliance As shown in FIG. 9, the reciprocal of the slope (rebound compliance) Cr of the load drop portion near the maximum load Pm in the load-displacement curve is determined.

The slope in this vicinity is determined by the tearing modulus Tma using the following formula, based on the assumption that stable fracture occurs when the fracture resistance of the test piece balances the spring constant of the load system.
Estimate t.

TIIlat=4P-E/σo-b-8((C+C,o
)/[1+C(r3P/'aΔC),])2'2-JE/σ0'''b-...(10) The tearing modulus Tll1at due to water droplets is estimated by the tearing modulus obtained from the crack propagation resistance curve. 'mat can be used to easily perform rough estimation.

The programming of the personal computer 38 is as described above.

Note that the personal computer 38 is provided with a dynamic elastoplastic fracture toughness value Jd via an interface (not shown).
, a printing device 53 that prints tearing modulus Tmat, etc., and an XY printer that displays compliance change rate ΔC/Co-displacement curve, crack growth resistance curve (JR curve), tearing modulus "mat-crack growth amount Δa curve, etc. A plotter 54 is connected.

Now, instrumented Charpy testing machine 1 configured as above.
The results of an instrumented Charpy test actually conducted using the dynamic characteristic measuring device 31 and the effects of the dynamic characteristic measuring device 31 will be explained together.

[Outline of test materials and test method] In this test, AS for reactor pressure vessels was mainly used as the test material.
TM A333B, using class 1 steel plate, some 50
83-0 (AI-Mca alloy), 7N01-T4 material (Al-Zn-Mg alloy), and 5841 (mild steel) were used. All of these are typical ductile materials that exhibit ductility at room temperature.

From these samples, a standard V shown in Fig. 10 was prepared so that the longitudinal direction was parallel to the rolling direction and the notch was parallel to the plate thickness direction.
A notched Charpy test piece 3a and a deep notch three-point bending test piece 3b shown in FIG. 11 were processed.

The dimensions of the standard V-notched Charpy test piece 3a are: test piece length L = 55M, test piece thickness B = 10 order, test piece width W = 1
0m, V notch length a=2.

The dimensions of the deep notch three-point bending test piece 3b are as follows: test piece length L=
55m, specimen thickness B = 10mm, specimen width W = 1
0rrvn, U notch length a = 4.5M, U notch bottom fatigue crack length a' = 1.5m (this fatigue crack is A
It was introduced in accordance with STM E399. ),
The ratio of the total initial crack to the specimen width is ao/W = 0.6.

When these test pieces 3a and 3b are placed on the anvil 4 or the stop block device 11 and hit with the hammer 5, the active gauge 2 attached to the side of the hitting part 6 of the hammer 5
3a causes a resistance change and outputs a load signal from the bridge circuit. Although the load signal at the time of dynamic destruction of the monthly interest rate ends in a short time, it is stored in the load digital memory device 34 after passing through the load adjustment device 33.

At the same time, the film potentiometer 21 mounted on the rotating shaft of the hammer 5 causes a resistance change and outputs a displacement signal from the bridge circuit. This displacement signal, like the load signal, passes through the displacement adjustment device 35 and is stored in the displacement digital memory device 36.

Here, in this embodiment, both digital memory devices 34.3
Since the sampling period of No. 6 can be arbitrarily set within the range of 2 to 999 μs, it is possible to deal with various materials having different times until breakage. Furthermore, since both digital memory devices 34 and 36 are provided for 10 channels, all load-displacement data from 10 tests can be stored, which has the effect of not interfering with the rapid progress of the test.

Subsequently, based on the load-displacement data stored in both digital memory devices 34 and 36, the microcomputer 37 serving as the first arithmetic unit processes the data, and further stores the same data and the external storage device 39. Based on the data, the personal computer 38 serving as the second arithmetic unit performs the data processing.

[Effectiveness of data processing by a microcomputer] ■Effectiveness of erasing the imaging wave superimposed on the load signal As mentioned above, in reprimanding using the moving average method, 1 non-pulling Zhou Ming Bayu stored in the load digital memory device 34 be influenced by. As an example, 7N
When a standard V-notch Charpy specimen 3a of O1-T/1 material was subjected to an instrumented Charpy test at a street speed of 5.1 m,
The corrected waveform (moving averaged waveform) of the rising portion of the load-time curve is shown in comparison with the original waveform.

Figure (a) shows the result of correction of the load-time curve recorded at the regular sampling period Δt=21Js, and the corrected waveform passes exactly through the center of the original waveform, indicating that the set point 1~. Off frequency f. is found to be appropriate.

The same figure (b) shows the sampling period △t=4m, the same figure (C)
shows the correction results of the load-time curves recorded at a sampling period of Δt=8 m, but there is a tendency that the correction gradually becomes excessive. This is mainly due to the fact that the sampling period Δt of this embodiment is based on the second standard, but it is considered that there is no problem in practice as long as the sampling period Δt≦8 μs. However, if the sampling period is longer than 8 μs, it is necessary to create a program that takes the sampling period into consideration.

■Effectiveness of determining maximum load @P and yield load P, First,
The maximum load pH1 could be determined accurately without any particular problems.

Subsequently, since the yield load ff1P is evaluated from the change in the slope of the corrected waveform, it is influenced by the effectiveness of the correction method. 12th
Figures (a) to (C) show the yield load ff1P determined from the corrected waveform at each sampling period.

However, there is an error of about 20% between each yield load ff1Py. This is considered to be caused by a difference in the amplitude of the vibration wave or the degree of correction rather than an error caused by the device. However, considering that it is originally quite difficult to accurately evaluate the dynamic yield load UP, it is considered to be sufficiently effective if the yield load Py can be determined within this error range.

■Effectiveness of calculating the nominal crack initiation energy Ei and the nominal crack propagation energy E. Furthermore, the accuracy of calculation of the nominal crack initiation energy Ei and the nominal crack propagation energy Ep by the microcomputer 37 is based on the conventional photographic method. By comparing it with that, it was confirmed that the surface was sufficiently high.

It should be noted that the time required for each of the above-mentioned analyzes (1) to (2) by the microcomputer 37 was only about 40 seconds, which was slightly shorter than the conventional analysis using photographic images.

[Stop Block Test] Next, a stop block test was conducted using a plurality of deep notch three-point bending test pieces 3b, and the crack initiation point and dynamic elastic-plastic fracture toughness value Jd were determined. Although this Jd value serves as a standard for confirming the effectiveness of the analysis by the personal computer 38 described above, this test itself is very useful because it can be analyzed by the personal computer 38.

This testing machine
Attach the ASTM to the same stop block device 11.
Set A333B deep notch three-point bending test piece 3b,
The load-displacement curve was recorded by striking from a hammer lift angle of 40' (impact velocity was 2.72 m). Also,
This testing machine was tested by replacing the blocks 13 with different thickness one by one and using different test pieces 3b.
A maximum displacement of 1 to 10# was applied to each.

After the impact, all the test pieces 3b were heated and colored, and after being immersed in liquid nitrogen, brittle fracture occurred and a fracture appeared. Thereafter, the fatigue pre-crack length a' and the crack propagation loss Δa were measured using a tool microscope to determine the crack initiation point.

FIG. 13 shows the relationship between the load-displacement curve obtained from water droplets and the crack growth area Δa. It is clearly seen that the crack initiation point exists before the maximum load fflPm. At this time, the energy E absorbed up to the point of crack initiation. corresponds to 68% of the nominal crack initiation energy Ei. The value of Eo/Ei varies depending on the material, and is 3341 and 0.42.5083 (
It was 0.59 for the A I-Mq gold alloy.

The Jd value determined from equation (4) using the present 1-tube block test method was 253.8 kJ/m2, which was a.

Note that this Jd value did not satisfy the valid condition of equation (6), so it became a dynamic fracture toughness value under plane stress.

Figure 14 shows the crack propagation resistance curve obtained by water spray (JR
curve).

[1.Efficacy of analysis using a personal computer] ■Effectiveness of estimating the crack initiation point using the compliance rate of change method In this test, a deep notch three-point bending test piece 3 of A333B was used.
b was struck from a hammer lifting angle of 140°, and the load-displacement curve was recorded. Next, FIG. 15 shows the results of estimating the crack initiation point by measuring the compliance change rate ΔC/Ce with respect to the displacement of the blower 1. The crack initiation point estimated by the water droplets almost coincides with that determined by the stop block test method described above, and can be said to be effective.

Note that the point at which the compliance change rate ΔC/Ce starts to rise corresponds to the displacement corresponding to the yield load ff1P point.

■Effectiveness of measuring dynamic elasto-plastic fracture toughness value Jd Energy E absorbed up to the crack initiation point estimated by the above compliance change rate method. The Jd value calculated from equation (4) was 239.1 kJ/m-. Although this Jd value was slightly smaller than the Jd value obtained by the S1-Tubplotter test method, they were in close agreement. From this, it was recognized that the compliance change rate method can be easily applied to the instrumented Charpy test method to determine the point of motion crack initiation. The inventor of the present invention has confirmed the effectiveness of this technique with other metal materials as well.

■Effectiveness of analysis of crack propagation resistance curve by key curve method Figure 16 shows the crack propagation resistance curve (JR curve) estimated by key curve method.

) are shown together with those evaluated by the stop block method. The two showed good agreement, and it can be said that the analysis using water droplets is effective.

■Tearing modulus Tma based on crack growth resistance curve
Effectiveness of analysis of t Next, FIG. 17 shows the tearing modulus Tmat obtained from the slope of the crack growth resistance curve (JR curve) by the above-mentioned key curve method with respect to the crack growth ωΔa. Maximum load P
The ductile crack grows stably up to just after point II1 (Δa = about 1.0 m), and in this range, the tearing modulus Tll1at due to water drop and 'm determined by the stop block method are
at almost match, and can be said to be effective.

■Effectiveness of analysis of tearing modulus Tmat by rebound compliance In summary, the results of Tll1at obtained using rebound compliance C6 are also shown in Figure 17, and immediately after the maximum load fflPm point, it is almost equal to the stop block method and key curve method. This shows the effectiveness of this method.

From the above, it was confirmed that the microcomputer 37 or personal computer 38 of this embodiment can quickly and accurately calculate various dynamic characteristic values of materials.

In particular, according to this embodiment, the dynamic elastoplastic fracture toughness Jd, tearing modulus 'mat, etc. of a material can be easily and quickly measured using an extremely small number of samples, that is, only one test piece.

These effects meet the on-site demands for simplicity and speed.

It should be noted that the present invention is not limited to the configurations of the embodiments described above, and may be modified and embodied as desired without departing from the spirit of the invention, for example, as described below.

(1) The dynamic characteristic measuring device of the present invention can also be embodied as a device connected to an instrumented impact test other than the instrumented Charpy radial impact test.

(2) The dynamic property measuring device of the present invention may be embodied as a device for measuring the dynamic properties of various materials other than the test side, such as metal materials, synthetic resin materials, form materials, and composite materials thereof. Can be done.

Effects of the Invention As detailed above, the present invention has the excellent effect of being able to quickly and accurately measure various dynamic property values of materials, and meeting the demands of the field for simplicity and speed. play.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an embodiment embodying the dynamic characteristic measuring device of the present invention, Fig. 2 is a schematic front view of the same embodiment, Fig. 3 is a perspective view of the step block device, Fig. 4 (a)
- (d) are curve diagrams schematically showing the method of determining the maximum load of the material using a microcomputer, Figure 5 is a flowchart of the determination method, and Figure 6 is the estimation of the crack initiation point using the compliance rate of change method. A curve diagram schematically showing the method, FIG. 7 is a curve diagram schematically showing the method of reprimanding crack generation energy,
Figures 8 (a> and (b) are curve diagrams schematically showing the key curve approximation method, Figure 9 is a curve diagram schematically showing the method for determining rebound compliance, and Figure 10 is a curve diagram schematically showing the method of determining rebound compliance. Figure 10 is a curve diagram schematically showing the method of calculating the rebound compliance. FIG. 11 is a perspective view of a deep notch three-point bending test piece, FIGS. 12(a) to (C) are characteristic diagrams showing examples of load signal correction by the microcomputer, and FIG. 13 is load-displacement. Figure 14 is a characteristic diagram showing the crack initiation point and crack growth maximum on the curve; Figure 14 is a characteristic diagram showing the crack growth resistance curve obtained by the stop block method;
Figure 5 is a characteristic diagram showing an example of estimating the crack initiation point using the compliance rate of change method, Figure 16 is a characteristic diagram showing the crack propagation resistance curve (plot) estimated by the key curve method, and Figure 17 is a characteristic diagram showing an example of estimating the crack initiation point using the compliance change rate method. FIG. 2 is a characteristic diagram showing tearing modulus determined by a block method, a key curve method, and a rebound compliance method. DESCRIPTION OF SYMBOLS 1... Instrumented Charpy testing machine, 31... Dynamic characteristic measuring device, 34... Digital memory device for load as a storage device, 36... Also digital memory device for displacement, 37... Microcomputer as an arithmetic device, 38...also a personal computer, 39
...External storage device as a storage device. Figure 4D Time displacement plastic displacement component Pf Displacement 10wJ Figure 12 (・0 50 100 '1502 (Xl 250 hours OA8) 0 0.5 4.0 Crack growth amount ja (mm) Displacement (-' ) Fig. 15 Displacement (:n) Fig. 16

Claims (1)

[Claims] 1. A storage device that converts and stores the load signal and displacement signal at the time of material failure obtained from an instrumented impact tester into digital data, and the load data and displacement signals stored in the storage device. A dynamic property measuring device comprising a calculation device that calculates dynamic property values of a material based on displacement data. 2. The dynamic property measuring device according to claim 1, wherein the dynamic property value is a dynamic elastic-plastic fracture toughness value J_d. 3. The dynamic characteristic value is tearing modulus T_m_a
_t. The dynamic characteristic measuring device according to claim 1.