JPS5911856B2 - Versatile tensile test equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tensile strength testing device, and more specifically, it is capable of performing various tensile D tests on high 25 molecular weight materials such as thermoplastic resins, fibers, and rubber. ,
This invention relates to a versatile tensile test device.

Among the various tests performed to determine the mechanical properties of polymer materials, the most widely used 3θ test is the tensile Y test.

Tensile tests for polymeric materials include tensile tests in which a sample is pulled at a constant speed, tests in which the strain rate applied to the sample is arbitrarily changed over time, and creep tests in which a constant stress is applied to the sample. Yes, depending on the purpose of the test,
5 test methods have been selected. Further, various tensile tests on polymeric materials are conducted in a wide temperature range of low temperature, normal temperature, and high temperature, and tensile test apparatuses suitable for each temperature range have been proposed. In order to measure stress, elongation, etc. in a tensile b test, a film or sheet-like sample is tightly clamped between two sets of clamps, and the mutual spacing between these clamps is changed at a constant speed to keep the sample constant. A device that records the stress, strain, time, and diagram during stretching at a stretching speed of
For example, it is described in Japanese Patent Publication No. 44-6744,
Are known.

The apparatus described in this publication can be fully utilized when the total amount of sample deformation is small, but when the total amount of sample deformation is large, the maximum amount of stretching that can be tested is limited by the gap between the spans. In addition, if a constant temperature bath is attached, the size of the bath is limited. Tensile tests are often conducted under high temperature conditions;
The specimen holding clamps of the test equipment are parallel plate or wedge-shaped), and when both ends of the specimen are held by the holding clamps at the same time under high temperature, the specimen will sag due to thermal expansion, and areas with a small amount of stretching will experience stress. The problem is that it cannot be measured. In such a case, first, only one end of the sample is held with a holding clamp, and when the sample reaches the measurement temperature, the other side of the sample is held. However, conventional parallel plate or cut-out clamps require the door of the thermostatic chamber to be opened before operation, and this operation inevitably causes a drop in the temperature of the thermostatic chamber.
It is necessary to heat the sample again to the measurement temperature. Furthermore, if you want to determine the amount of strain that can be recovered from the sample, after the stretching is completed,
If the temperature of the sample drops by opening the door of the thermostatic chamber and removing one of the holding clamps holding the sample from the sample, measure the amount of shrinkage of the sample after raising the temperature to the measurement temperature again. Then, the amount of recovery strain of the sample is determined. However, this method has the disadvantage that stress relaxation is ignored, resulting in a value that is far from the true recovery strain.
Recently, as a clamp for tensile C testing equipment, a roll clamp (RO
A tensile testing device equipped with a vertical clamp has been proposed (see, for example, Japanese Patent Publication No. 51-47068). This device is suitable for performing tensile tests on rod-shaped samples, and there is no mention of the details of the clamp mechanism used when pulling sheets or films. Depending on the type of polymer material, properties such as stress and elongation may be affected by time or strain rate. When performing a tensile test on a sample with such properties,
It is necessary to keep the strain rate constant.

This requirement cannot be met by a constant tensile rate. This is because when a sample is pulled at a constant tensile speed, the amount of elongation of the sample increases in proportion to time, but on the other hand, as the gauge distance increases, the deformation that occurs within a unit time gradually slows down. This is because it decreases to For example, if the length of the sample increases ten times, the strain rate decreases to one-tenth of the initial strain rate. For this reason, there has been a desire to develop an apparatus that can perform tests with a constant strain rate. A stretching step is involved when producing a film, sheet, or filament from a polymeric material, or when producing a molded article from a film or sheet by a thermoforming method.

The stretching in these steps varies in strain rate, temperature conditions, etc. and is not constant. When producing a molded product from a film or sheet by thermoforming, the film or sheet is heated to a moldable temperature, and then a vacuum and/or compressed air is applied to the film or sheet to stretch the sheet. Give it the desired shape. If the stretching process during thermoforming is reproduced using a tensile test device, the stress, strain, time, and diagram of this stretching process can be obtained. These data can be utilized to examine appropriate materials and appropriate molding conditions. However, until now, there has been no known program-controlled tensile testing device that can arbitrarily change the strain rate applied to a sample over time. The process of applying a constant stress to a sample during a tensile test and measuring the change in deformation over time is called a creep test.

An ideal creep test requires that a predetermined stress be suddenly applied to a sample that has not been subjected to any external force in the past, and then kept constant. However, when using a conventional tensile b testing machine, it is not possible to apply stress to the sample instantaneously, and a finite amount of time is required. Furthermore, in order to keep the stress constant, the load must be controlled according to the change in cross-sectional area due to sample deformation. Since it is extremely difficult to control the load in a dead weight type creep tester, a constant load creep test is generally performed. As a creep test device that controls the load according to the cross-sectional area change due to the deformation of the sample, for example, the Japanese Patent Publication No. 43-2575
It is described in Publication No. 4.

With the equipment described in this publication, if the total deformation of the sample is large, the amount of stretching that can be tested depends on the gap between the spans of the equipment, and if the equipment is equipped with a constant temperature oven, is limited by the size of In addition, creep tests are often conducted at high temperatures, and the sample holding clamps of conventionally known creep test devices are parallel plate or wedge-shaped, similar to the clamps of other tensile strength test devices.
When holding a sample under high temperature, as with other tensile tests, there are problems such as sagging due to thermal expansion of the sample, opening the door of the thermostatic chamber to hold the sample, and reheating the temperature inside the thermostatic chamber. It was hot.

For this reason, the development of a constant stress creep test device that does not cause the above problems has been awaited. As described above, there are many types of tensile tests, and testing apparatuses are known depending on the purpose of the test.

In order to perform many types of tensile V tests, it is necessary to prepare many test devices depending on the purpose, which reduces costs and costs.
There were problems with the installation location, equipment maintenance, etc. In view of this situation, the present inventors developed a device that can perform various tensile tests, namely, a device that allows the sample to be easily attached and detached, a tensile test that maintains a constant strain rate, and a device that allows the strain rate applied to the sample to be controlled over time. To provide a multi-purpose tensile dielectric test device capable of performing tensile tests, etc., which can be changed arbitrarily, and measuring the stress relaxation of a sample and the amount of recovery strain of a sample during these tensile b tests, as well as capable of performing a constant response kakureve test. As a result of intensive studies aimed at this purpose, the present invention has been completed.

The gist of the present invention is to include a sample fixing clamp connected to a load detection device, and a sample tensioning roll clamp consisting of a pair of rolls provided opposite to the sample fixing side clamp. The sample clamping mechanism includes a roll clamp connected to a drive motor so as to be rotatable in mutually opposite directions, and a means for approaching and separating the roll gap; the sample is rotated by the operation of the drive motor. A detection mechanism consisting of a load detection device that detects the tension generated when the sample is stretched by a roll clamp, and a stretching amount detection device that detects the amount of stretching of this sample; An arbitrary function generator that inputs the strain rate, a function divider that divides the input voltage so that the input arbitrary function falls within the speed change range of the drive motor, and a signal sent from the function divider to control the drive motor. The strain rate applied to the sample is controlled over time by an inverting circuit that has the function of returning the rotation speed of the motor from a high speed state to a low speed state, and a PID amplifier that controls the rotation speed of the drive motor to an input function value. Mechanism for arbitrarily changing: Switch the circuit from the above arbitrary function generator to a constant strain rate setter, and rotate the sample tensioning roll clamp at a rotation speed corresponding to the strain rate set in this constant strain rate setter. Mechanism for giving a constant strain rate to the sample; SO, σ, dl(t) are obtained from the initial cross-sectional area SO input device of the sample, the stress σ setting device, and the stretching amount dl(t) detector, respectively.
) into the calculation formula, calculate the tension F(t) of dl(t) F(t) - σSOexp(1?), and calculate the tension F(t) and the measured tension F7 detected from the load detector. (t) to a PID amplifier, and a constant stress creep test mechanism equipped with a control circuit that drives the sample pulling roll clamp so that the electrical difference therebetween becomes zero; The invention resides in a multi-purpose tensile testing device characterized by the following.

Hereinafter, the multi-purpose tensile test device according to the present invention will be explained in detail based on the drawings, but the present invention is not limited to the following explanation unless it exceeds the gist thereof.

Fig. 1 is a side view of the multi-purpose tensile testing device 1 according to the present invention, Fig. 2 is a schematic plan view of a portion of Fig. 1, and Fig. 3 is a longitudinal cross-section in the - part of Fig. 2. 4 is a block diagram, FIG. 5 is a diagram showing an example of a function set in an arbitrary function generator, and FIG. 6 is a diagram showing a function generated by an arbitrary function generator divided by a function divider, An example of a function whose part is inverted using an inverting circuit is shown below.

In the figure, 1 is a load detection device, 2 is a sample fixing side clamp, 3 is a sample, 4 is a fixed roll, 5 is a moving roll, 6 is a fixed roll drive shaft, 7 and 7' are rotation bearings, 8, indicate the brackets of the rotary bearings 7, 7', respectively.

9 is a moving roll drive shaft, 10 is a taper pin, 11 is a universal joint, 12 is a pin, 13 is a drive shaft, 14
, 15 are gears, and 16 and 16' are drive shafts 9 and 13, respectively.
17 and 1T' indicate the rotation bearing 1, respectively.
6.1V slide bracket is shown.

18 is a guide shaft of the drive shaft 9; 19 is a moving shaft of the drive shaft 9; 2
0 is a dedicated bearing for the moving shaft 19, 21 is a bracket for the bearing 20, 22 is a connecting rod, 23 is an air cylinder, 24 is a base plate, 25 is a column, 26 is a constant temperature oven, 27 is a door, 28
29 indicates a sample tray, 29 indicates a sample tube, and 30 indicates a sample tip.

31, 32 are servo motors, 35, 36 are tacho generators, 39, 40, 41, 42 are reducers, 43, 4
4, 45, 46 are clutches, 47 is a brake, 48 is a slit disk, 49 is a pulse sensor, 50 is a preset counter, 51 is a D/A converter, 52 is a stretching amount output terminal, 53 is a strain meter, 54 is the load output terminal, 5
5 is a solenoid valve, 56 is a compressed air source, 57 is a switch, 58 is a clutch/brake/solenoid valve manual operator, and 59 is a terminal connected to the clutches 43, 44, 45, 46 and the brake 47.

60 is an arbitrary function generator, 61 is a constant strain rate setter, 62 is a switch, 63 is a function divider, 64 is a switching signal generator,
65 is an inversion circuit, 66 is a switching circuit, 67 and 68 are PIDs.
Amplifier, 69 and 70 are servo amplifiers, 71 and 72 are 10
g amplifier, 73 is a terminal connected to the clutches 43, 44, 45, 46, 74 is an arithmetic unit, 75 is a σ setting device, 76
indicates an SO input device, and 77 indicates a load converter.

The multi-purpose tensile test device according to the present invention includes a load detection device 1
A sample fixing side clamp 2 connected to this load detection device is provided, and a roll clamp for pulling the sample consisting of a pair of rolls 4 and 5 is further provided opposite to this sample fixing clamp.

As shown in FIG. 1, the load detection device 1 is supported by a column 25 on one side, and is provided with a sample fixing side clamp 2 on the other side.

The sample fixing side clamp 2 can be of a conventionally known structure such as a wedge type, parallel plate type, or eccentric roll type. The apparatus according to the present invention fixes one end of the sample 3 with the sample fixing clamp 2, fixes the other end with a pair of roll clamps, rotates the rolls 4 and 5 in opposite directions, and pulls the sample. It is structured. One of the pair of rolls is called a fixed roll, which can rotate freely but cannot make any other movements. The fixed roll 4 is attached to a drive shaft 6 and has rotating bearings 7, 7'.
and brackets 8, 8' are attached to the base plate 24. The other roll 5 can not only rotate, but also press the sample against the fixed roll 4 side and separate it from the sample 3. The pair of rolls are configured to rotate with the sample sandwiched therebetween.

The moving roll 5 is connected to a drive shaft 9, and this drive shaft 9 is attached to a rotation bearing 16. A taper pin 10 and a universal joint 11 are attached to one end of the drive shaft 9.
is provided, and is incorporated into the slide bracket 17 together with the rotation bearing 16. A pin 12 and a drive shaft 13 are connected to the other end of the universal joint 11).
, the drive shaft 13 is connected to the bracket 11 together with the rotary bearing 16''.
It is built in and can be rotated. The drive shaft 6 and the drive shaft 13 are configured to rotate simultaneously by gears 14 and 15. That is, when the drive shaft 6 is rotated by some means, the gear 14 rotates, and this rotation is transmitted to the drive shaft 13 by the gear 15, and as a result, the fixed roll 4 and the moving roll 5 can be rotated simultaneously. become. In such a tension roll clamp, one side is a fixed roll and the other side is a moving roll, and the means for moving the moving roll toward and away from the fixed roll can be configured as follows.

That is, a moving roll guide shaft 18 is provided above or below the moving roll 5 in a direction perpendicular to the axis of the fixed roll 4, and is connected to the moving roll 5.
It is preferable to provide a compressed air cylinder mechanism for approaching and separating the moving rolls in a direction perpendicular to the axis of the moving rolls.

In this case, when the movable roll guide shaft 18 is provided below the movable roll 5, it is not necessary to provide it directly below it, and as shown in FIG.
7, and the drive shaft 9 inside the slide bracket 17
, it is preferable that the rotary bearing 16 be moved together.
As shown in FIG. 2, the moving roll approaching/separating compressed air cylinder mechanism is composed of a moving shaft 19 connected to a slide bracket 17 of a drive shaft 9, a connecting rod 22, and an air cylinder 23. 19 is preferably supported by a bearing 20 attached to a base plate 24 and protected by a bracket 21. When compressed air is introduced into the head side of the air cylinder 23, the piston inside the cylinder is moved to the right in Fig. 2. , the movement reaches the sliding bracket 17 of the drive shaft 9 via the connecting rod 22 and the moving shaft 19.

As a result, the slide bracket 17 of the drive shaft 9 moves toward the drive shaft 6 along the movable roll guide shaft 18, and the movable roll 5 is pressed against the fixed roll. When compressed air is introduced into the connecting rod side of the air cylinder 23, the piston within the cylinder can be moved to the left in FIG. The multi-coat tensile test device according to the present invention further includes a program control mechanism that can arbitrarily change the strain rate applied to the sample over time.

The program Fbl leg mechanism, which can arbitrarily change the strain rate applied to the sample over time, uses multiple servo motors and multiple decelerations with different speed ranges to control the rotation of the roll clamp for pulling the sample. A mechanism that changes the speed of the clamp over a wide range by selectively combining them, and a mechanism that changes the speed of the rotation of the clamp over a wide range according to a predetermined function depending on the purpose of the test. It is composed of In order to vary the rotational speed of the sample pulling roll clamp over a wide range, a plurality of servo motors and a plurality of reducers with different speed ratios may be selectively combined. In the tensile D test, the test is conducted by controlling the rotational speed of the roll clamp, and the rotational speed N of the roll clamp is required to have a wide speed change range and to be highly accurate.

In the apparatus according to the present invention, a plurality of servo motors are installed in order to meet this requirement. FIG. 4 shows an example including two servo motors 31 and 32. It is preferable that the speed change range of each of these servo motors is limited to about 1XN to 10XN, and that a range with high rotation accuracy is used. These servo motors are combined with a plurality of reducers having different speed ratios.

FIG. 4 shows an example in which two reduction gears are combined for one servo motor. The servo motor 31 has a rotation speed N
The servo motor 32 has a reducer 39 that reduces the speed to 1/103 and a reducer 40 that reduces the speed to 1/10.
By combining the reducer 41 that decelerates to 102 and the reducer 42 that decelerates to 1/1, the final rotational speed given to the roll clamp can be continuously changed in the range of 0.001 x N to 10 x N. can do.

For example, if the servo motor 31 and reducer 39 are combined, a rotation speed of 0.001XN to 0.01XN can be obtained, and if the servo motor 32 and reducer 41 are combined, a rotation speed of 0.01XN to 0.01XN can be obtained. Rotational speeds up to 1×N can be obtained.

When the servo motor 31 is combined with the reducer 40, 0.
A rotation speed of 1×N to 1×N is obtained, and when the servo motor 32 and reducer 42 are combined, the rotation speed is 1×N to 10×N.
The rotation speed is obtained. The rotation speed of the roll clamp can be changed by switching the clutches 43, 44, 45, and 46. 0
．． The speed can be changed continuously within the range of 001XN to 10XN.

Tacho generators 35 and 36 are connected to the servo motors 31 and 32, respectively, and each tacho generator has a voltage of V~1 when the servo motor rotates at N~10N.
A voltage of 0V volts is generated and fed back to servo amplifiers 69, 70 via 10g amplifiers 71, 72, which are logarithmically varied from 0 to 1V volts.

The apparatus according to the present invention not only allows the rotation of the sample tension roll clamp to be changed over a wide range using the above-mentioned mechanism, but also adjusts the strain rate according to a predetermined function according to the purpose of the test. Equipped with a mechanism to change the The strain rate applied to the sample is set in advance in the arbitrary function generator 60.

An example of functions set in the arbitrary function generator 60 is shown in FIG. Figure 5 A shows an example in which the strain rate rises in a parabolic curve in the early stage, reaches the maximum value in the middle stage, and then decreases in the opposite curve to the initial stage. , Figure 5 (c) shows an example in which the strain rate increases in proportion to time.The strain rate increases in proportion to time up to the middle, reaches the maximum value in the middle, and in the second half it becomes the opposite of the first half. Figure 5-2 shows an example in which the strain rate decreases in inverse proportion to time.In the early stage, the strain rate increases in proportion to time, maintains its maximum value in the middle stage, and in the late stage, it becomes different from the initial value. On the contrary, examples are shown in which the strain rate decreases in inverse proportion to time. The functions set in the arbitrary function generator 60 are not limited to the four types shown here, but can of course be changed to an exponential function) or other types of functions depending on the purpose of the test. . The strain rate applied to the sample changes over time according to the strain rate one-hour function set in the arbitrary function generator 60, and its maximum value is larger than the speed change range of each servo motor. Therefore, it is necessary to divide the set value into values corresponding to the speed change range of each servo motor.

This division is performed by a function divider 63. The function divider 63 further converts the divided set value into a value corresponding to the speed change range of the servo motor, for example from 0 to 1 V volts, and supplies it to the summing point of the servo amplifier together with the feedback signal. If the function represented by A in Figure 5 is set in the arbitrary function generator and the roll clamp is rotated according to this function, this function will cause the roll to rotate in the process of O-P-Q-R-S. The clamp rotates from a low speed state to a high speed state, and during the S-T-U-V-W process, it rotates from a high speed state to a low speed state.

This rotation is achieved by alternately using two servo motors. That is, one servo motor is (0-P
), (QR), (S-T) and (U-V), and the other servo motor shares the sections (P-Q), (R-S).
), (T-U) and (V-W). The rotation speed of the servo motor in each section is N to 10N.
rotation or 10N-N rotations. (0-P) and (V
-W) section is 1/103, (P-Q), and (U-V
) section is 1/102, (QR) and (T-U
) section is 1/10, and furthermore (R-S) and (S
-T) section, by rotating the roll clamp via a speed reducer with a reduction ratio of 1/1, a rotation range of 0.001 N-JON can be obtained. One of the servo motors, in a certain section of the set function,
After completing N to 10N rotations or 10N-N rotations, it is necessary to decelerate or accelerate to N or 10N rotations and wait 4 times before reaching the next assigned section.

Therefore, once one servomotor has finished operating in a certain section, this function j is executed while the other servomotor is operating in the next section of the function according to the function of that section. It rotates in the reverse direction and waits at N or 10N rotations, which is the number of rotations at the time of departure of the next division to be shared.

In this way, an inversion circuit is used to cause the servo motor to reverse the function and wait for N or 10 N rotations before reaching the starting point.

In other words, the servo motor that rotates from the function divider directly via the PID amplifier and servo amplifier rotates the roll clamp, and the servo motor that rotates via the PID amplifier and servo amplifier via the inverting circuit is not connected to the roll clamp. First, trace the function backwards and get N or 1.
The engine will wait in a state where the rotation is set to 0N. A mechanism for changing the strain rate according to a predetermined function can be operated by the following procedure.

When the function represented by A in FIG. 5 is set in the arbitrary function generator 60 and its output is input to the function divider 63, the input voltage is divided by the function divider 63 into increments of 0 to 1 volt. , the next inverting circuit 65 or PID amplifier 67, 68
supplied to

The division is carried out in accordance with a signal issued from the switching signal generator 64, and at the same time this signal causes the clutches 43, 44,
45, 46 and the switching circuit 66 are selected or switched. That is, when the function A is supplied to the function divider 63, this function becomes O→1V (0-P), 1V→2
V (P-Q), 2V → 3 (QR), 3V → 4V → 3V
(R-S-T), 3V → 2V (T-U), 2V → 1V (
It is divided into seven parts: U-V) and 1V→0 (V-W).
The division is shown in solid lines in Figure 6 as 01, 12, 23.
, 343, 32, 21, 10. The divided functions are divided into two routes: one is supplied as is to contacts A and D of the switching circuit 66, and the other is supplied to contacts B and C of the switching circuit 66 via the inversion circuit 65. The inverting circuit 65 receives the divided function and inverts the polarity, and uses a limiter to invert the polarity to the upper side near 1V volt. It has the function of cutting off the lower side near V volt and outputting 0 to 1 volt. The functions that have passed through the inversion circuit 65 in this way are indicated by dotted lines in FIG.
, 21, "denoted as r. These reference voltages of 0 to 1 V
The bolt controls the rotation speed of the servo motors 31 and 32 from N to 1.
Control to 0N rotation. While the function is changing over time between O and 1V volts, that is, when the output of the function divider 63 is within the range indicated by 01 in FIG. 6, the A and C sides of the switching circuit are turned on. B. PID amplifier 67 and 6
8 are supplied with the 01 function and the 01 function shown in FIG. N → 10N rotation and 10N-
Rotates +N rotations.

At this time, only clutch 43 is connected to the load, and the others are disconnected. In other words, the load mechanism is decelerated to 1/103 by the reducer 39 and has a power of 0.001.
Rotation that follows the 01 function is transmitted by ×N to 0.01 × N rotations. When the function reaches 1 volt, the function divider 6
The output of 3 changes to the 12 function shown in FIG. 6, and at the same time, the contacts of the switching circuit 66 switch to B and D, and only the clutch 45 is connected to the load, while the others are disconnected.
The rotation of the servo motor 32 is then reduced to 1/2 by the reducer 41.
102, following the 12 function, 0.01×
N~0.1XN rotation and is transmitted to the load mechanism.
Clutches 43, 44, 45, 46 have a function of 1 volt,
Each time the voltage changes to 2 volts, etc., it receives a signal sent from the switching signal generator 64 and is switched.

Division of the function set in the arbitrary function generator 60 can be performed by switching the bias of the input amplifier of the function divider 63 using the sequence circuit of the switching signal generation circuit 64.

FIG. 5 shows an example where the function y=f(t) is 0≦y≦4V. The amount of stretching of sample 3 is determined by using a slit disk 4 on the drive shaft 6.
8 is attached, the pulse sensor 49 detects the slit in the disc, and the preset counter 50 adds up.

The number of slits in the slit disk 48 is preferably in a specific relationship with the circumference of the roll 4. For example, the circumference of the roll is 10
If the diameter is 0 mm and the number of slits in the slit disk is 100, then one slit represents 1 mm. The amount of stretching of the sample 3 is determined by converting the amount accumulated in a bristle counter 50 into an analog value using a D/A converter 51, which is connected to a stretching amount output terminal 52, and used for recording or control.

The force generated when the sample 3 is stretched is applied to the sample fixing side clamp 2.
is connected to the load detection device 1, which is connected to a strain meter 53, and connected to a load output terminal 54, which is used for recording or control.

If the switch 57 is switched from G (automatic) to H (manual), the clutches 43, 44, 45, 46, brake 47,
The solenoid valve 55 can be manually operated by a clutch/brake/solenoid valve manual operation circuit 58. Clutch manual operation switches are provided independently for the clutches 43, 44, 45, and 46, and when the switch of any clutch is turned on, the electromagnetic brake 47 is disconnected and the roll clamp mechanism is connected to the drive mechanism. , any rotation speed (strain speed)
The rolls 4 and 5 can be rotated. When the clutch switch is turned off, the electromagnetic clutch is disengaged, the electromagnetic brake is applied, the roll clamp mechanism and the drive mechanism are separated, and rotation of the roll clamp can be forcibly stopped. When the solenoid valve 55 is turned on, compressed air can be sent to the head side of the air cylinder 23 to press the moving roll 5 toward the fixed roll 4 side.

When the solenoid valve 55 is turned off, compressed air is sent to the connecting rod 22 side of the air cylinder 23 and the moving roll 5
can be separated from the fixed roll 4. When performing a tensile v test using the testing apparatus according to the present invention, the distance between the rolls 4 and 5 is widened by manual operation, the sample 3 is held in the sample fixing side clamp by hand, and then the solenoid valve 55 Turn on the switch and place the sample 3 in the roll clamp 4. , 5 to attach the sample.

Turn off the clutch and brake switches, rotate the roll drive mechanism at a predetermined number of rotations, then turn on the clutch switch and rotate the roll clamp. Immediately switch switch 57 to G automatic, switch 6
2 in F, it becomes possible to perform a tensile test while changing the strain rate over time according to a predetermined function. The versatile tensile test device according to the present invention includes a mechanism for performing a tensile test while applying a constant strain rate to a sample.

To give a constant strain rate to the sample, an arbitrary function generator 60
Instead, a constant strain rate generator 61 is provided.

A rotational speed corresponding to the strain rate set in the constant strain rate generator 61 is applied to the roll clamps 4 and 5, and a constant strain rate tensile test can be performed. The multi-purpose tensile strength testing device according to the present invention is equipped with a mechanism that performs a creep test while controlling the load according to the change in cross-sectional area due to deformation of the sample. The means can be assembled as follows. The cross-sectional area of the sample before the start of the creep test is SO, the distance between the sample fixing side clamp and the sample tension roll clamp (for stress loading) is dl(t
), and assuming that the Poisson's ratio is 0.5 or close to it, the cross-sectional area S(t) of the sample is the following (1
) is expressed by the formula. Also, if the force at that time is F(t), the stress σ is expressed by the following equation (2). . σ=F(
t)/S(t) ・・・・・・(2
) Using the above relationship, the fixed roll 4 and the moving roll 5 are adjusted so that the force F detected by the load detection device 1 and the strain meter 53 follows F(t) derived from equation (2). A constant stress test can be performed by controlling the rotation speed and applying a constant stress to the sample.

F(t) is expressed by the following equation (3) from equations (1) and (2) above.

F(t) in equation (3) is calculated by the arithmetic unit 74.

The SO is actually measured in advance for the sample to be subjected to the creep test, and this value is supplied from the SO input device 76 to the calculator 74.
An arbitrary value of σ is supplied from the σ setter 75 to the arithmetic unit 74. dl(t) is obtained from the output of the D/A converter 51, and 2 is the distance between the sample fixing side clamp and the stress loading roll clamp, which is an apparatus constant. F(t) in equation (3) is calculated by the arithmetic unit 74 by supplying various variables and constants to the arithmetic unit 74 as described above.
The output F(t) of the arithmetic unit 74 is transmitted to the strain meter 53.
With the force F fed back from the load transducer 7
7, and its output passes through switch 62 J.
It is supplied to the PID amplifier 67 or 68 through the same route as in the case of time function control of the strain rate, and its output is sent to the servo amplifier 6.
9 or 70.

The servo motor 31 or 32 outputs the output F of the arithmetic unit 74.
(t), and therefore the fixed roll 4
, the rotation speed of the moving roll 5 is controlled.

In order to minimize the run-up period until the set stress σ is reached, the rolls 4 and 5 of the roll clamp are rotated at high speed. The constant response characteristic of the sample can be obtained by recording the output of the D/A converter as a relationship with time from the stretching amount output terminal 52.

The multi-purpose tensile test device according to the present invention has the above-mentioned structural features, but when performing various tensile tests in a high-temperature atmosphere, the sample fixing side clamp 2 and the roll clamp for sample tension b are required. can be installed in the constant temperature bath 26.

When performing a tensile test under high temperature, the amount of sample deformation is generally large, but a sample tray 28 can be installed under the roll clamp for sample tension to receive the sample. For example, a hole is made in the sample tray 28, and then a constant temperature bath 26 is inserted.
It is also possible to provide a sample tube 29 on the heat insulating wall surface of the sample tube 29 through which the sample can pass, and a sample tip 30 for receiving the sample below the sample tube 29. The multi-purpose tensile test device according to the present invention can perform tensile tests with programmed strain rate control, low strain rate tensile tests, constant stress creep tests, stress relaxation of samples during tensile tests, recovery strain amount of samples, etc. can be found.

To measure the stress relaxation of a sample using the apparatus of the present invention, switch 62 to E, and adjust the strain rate using constant strain rate setting device 61 to minimize the time required to reach the set stretching amount. However, an arbitrary pulse is set in the preset counter 50 in advance, the pulses sent from the stretching amount detection section are counted, and the brake 47 is actuated by the signal output from the preset counter 1 in the preset count state. Then, the electromagnetic clutch D can be activated to stop the rotation of the openings 4 and 5.

In this case, the switch 57 is set to the G automatic side.
To measure the amount of recovery strain using the device of the present invention, the terminal of the switch 59 is also connected to the solenoid valve 55, and the rotation of the openings 4 and 5 is performed as in the case of measuring stress relaxation. The solenoid valve 55 of the air cylinder 23 is switched in response to a signal sent from the preset counter 50, and the moving roll 5 is separated from the fixed roll 4. As a result, one end of the sample becomes free, the sample recovers its strain, and the amount of recovered strain can be measured. By switching the switch 57 to G, it can be operated automatically. The multipurpose tensile strength testing device according to the present invention has the following advantages, and its industrial utility value is extremely large. 1. Regardless of the shape of the constant temperature bath, the sample can be stretched until it breaks.

In addition to the conventional lead screw and crosshead mobile tensile test equipment, the clamp for stretching the sample is
The lead screw is mounted on a crosshead that is movable along a rod or rod.

When pulling a sample with this conventional tensile D test device, the maximum amount of stretching of the sample is limited by the length of the lead screw of the device, the length of the constant temperature bath if it is equipped, etc. be done. For example, with conventional equipment, the initial length of the sample is
5011, and if you try to stretch it to 10 times the length, the length of the constant temperature bath will need to be at least 1500m + α (α is the length of parts such as clamps). In contrast, in the apparatus according to the present invention, the sample can be stretched until the sample breaks while keeping the distance 20 between the sample fixing side clamp and the sample tensioning roll clamp constant.
The same applies when performing a cleave test on a sample. 2 Strain rate program control is easy.

In thermoforming of synthetic resin sheets and films, the strain rate applied to the synthetic resin sheets and films often changes over time.

Therefore, in order to develop synthetic resin materials suitable for thermoforming, etc., and to search for the appropriate molding conditions for a certain synthetic resin sheet or film, it is necessary to conduct tensile tests under conditions that are almost the same as the actual molding conditions. . Such tests are preferably carried out by varying the strain rate as a function of time according to a predetermined program. If the above tensile test in which the strain rate is program-controlled is to be performed using a conventional lead screw/crosshead moving type tensile test device, the method for controlling the crosshead moving speed would be too complicated.

For example, in the simplest constant strain rate tensile test, the crosshead movement speed is 1, the strain rate is ε, and the strain rate after time t is ε.
If t, then v1=10iexp(It) ゛゜゜“゜゜(4) As expressed in equation (4), 1 must accelerate as an exponential function of time.

This requires a drive motor with an extremely wide variable speed range and a complex control mechanism. On the other hand, in the apparatus according to the present invention, by setting the circumferential speed V2 of the roll of the roll clamp for sample tension to be constant, a constant strain rate tension v test is possible.

Furthermore, when changing the strain rate as a function of time,
Conventional lead screw and crosshead type tensile testing equipment requires a more complex control mechanism.

For example, when the strain rate ε is changed as a linear function of time, i=Klt (5) [In equation (5)], k1 is an apparatus constant.

k1 has the same meaning in the following formulas. ], the crosshead moving speed V1 is V1=Kl
tlOexp (single)... (6) It is necessary to control the speed expressed by the equation (6).

On the other hand, in the apparatus according to the present invention, the circumferential speed V2 of the roll of the sample tensioning roll clamp is set to V2-K2t・
...(7) [In equation (7), K2 is a device constant.

] It is sufficient to simply control the speed to be expressed by equation (7). As the strain rate becomes more than a quadratic function of time, the control mechanism for crosshead movement becomes more complex. 1 constant stress creep test can be easily performed.

In conventional constant-load type creep test equipment, as the amount of sample deformation increases, the cross-sectional area of the sample decreases and the applied stress increases.However, in order to accurately maintain the stress applied to the sample at a predetermined value, In this case, the adjustment of the correction weight must be finely tuned, which is a complicated process. On the other hand, in the device according to the present invention, the tension is F(t
), a control circuit may be added to control the circumferential speed of the roll of the sample pulling side roll clamp.

4 By adjusting the air pressure of the air cylinder 23,
Since the force for clamping the sample can be changed arbitrarily, the sample can always be clamped with a constant pressure even if the sample is stretched and its thickness is reduced.

Since the sample is clamped using a combination of an air cylinder and a solenoid valve, the sample can be quickly and easily attached and detached by simply turning on and off an electric switch.

5. When performing high-temperature tensile tests, the sample can be clamped and unclamped without opening the door of the thermostatic chamber, so it is possible to obtain various highly accurate data during high-temperature tensile tests. Obtainable.

7. Since the strain rate applied to the sample can be changed arbitrarily as a function of time and time, it is useful when producing films or filaments from polymeric materials, or when making films or sheets into molded products using thermoforming. In addition, it is possible to reproduce the stretching process applied to polymeric materials, and the various data obtained can be used to examine appropriate materials and appropriate molding conditions.

[Brief explanation of the drawing]

FIG. 1 is a side view of an example of the multi-purpose tensile b testing device according to the present invention, FIG. 2 is a schematic plan view of the - part of FIG. 1, and FIG.
The figure is a vertical side view of the - part of Figure 2, Figure 4 is a block diagram, Figure 5 is a diagram showing an example of a function set in an arbitrary function generator, and Figure 6 is a diagram showing functions generated by an arbitrary function generator. Here is an example of a function in which a function is divided by a function divider and a part is inverted by an inverter. 1... Load detection device, 2... Sample fixing side clamp,
3... Sample, 4... Fixed roll, 5... Moving roll, 6... Fixed roll drive shaft, 9... Moving roll drive shaft, 11... Universal joint, 13...
Drive shaft, 14, 15... Gear, 18... Guide shaft of drive shaft 9, 19... Moving shaft of drive shaft 9, 22... Connection rod, 23... Air cylinder, 26...・Thermostatic chamber, 31, 32... Servo motor, 35, 36...
Tacho generator, 39, 40, 41, 42... Reduction gear, 43, 44, 45, 46... Clutch, 40.
... Brake, 48 ... Slit disk, 49 ... Pulse sensor, 50 ... Briset counter, 51
. . . D/A converter, 52 . . . Extension amount output terminal, 53
...Strain meter, 54...Load output terminal,
55... Solenoid valve, 57... Switch, 58... Clutch/brake/electromagnetic valve manual operator, 60... Arbitrary function generator, 61... Constant strain speed setting device, 62... Switch, 63...Function divider, 64...Switching signal generator, 65...Inverting circuit, 66...Switching circuit, 67
, 68... PID amplifier, 69, 70... Servo amplifier, 71, 72... 10g amplifier, 74... Arithmetic unit, 75... σ setting device, 76... SO input device, 77
...Load converter.

Claims (1)

[Claims] 1 Equipped with a sample fixing clamp connected to a load detection device, and a sample tensioning roll clamp consisting of a pair of rolls provided opposite to this sample fixing side clamp, and the sample tensioning roll clamps are arranged in opposite directions. A sample clamping mechanism rotatably connected to a drive motor and provided with means for approaching and separating the roll gap; when a sample is stretched by a sample pulling roll clamp rotated by the operation of the drive motor; A detection mechanism consisting of a load detection device that detects the tension generated in the sample, and a stretching amount detection device that detects the amount of stretching of this sample; an arbitrary function generator that inputs a predetermined strain rate as a function of time; A function divider that divides the input voltage so that an arbitrary function falls within the speed change range of the drive motor, and a signal sent from the function divider returns the rotational speed of the drive motor from a high speed state to a low speed state. A mechanism that arbitrarily changes the strain rate applied to the sample over time, consisting of an inverting circuit with a function and a PID amplifier that controls the rotation speed of the drive motor to the input function value; A mechanism for applying a constant strain rate to the sample by rotating the sample tensioning roll clamp at a rotation speed corresponding to the strain rate set in the constant strain rate setting device; Initial cross-sectional area So input device,
From the stress σ setting device and the stretching amount dl(t) detector,
Input So, σ, and dl(t) respectively into the arithmetic expression, and calculate F(
Tension F(t)=σSoexp(-dl(t)/l)
t), and the tension F(t) and the measured tension F'(t) detected from the load detector are supplied to the PID amplifier, and the sample is adjusted so that the electrical difference becomes zero. A multipurpose tensile testing device comprising: a constant stress creep testing mechanism equipped with a control circuit for driving a tensioning roll clamp;