JP3237586B2 - Material testing machine and biaxial loading testing machine driven by multiple actuators - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-axis loading device used for evaluating the performance of a material testing machine and a seismic isolation rubber for loading a specimen by driving a plurality of actuators in synchronization. Related to testing machine.

[0002]

2. Description of the Related Art Conventionally, there has been known a biaxial loading tester for measuring the shear deformation of seismic isolation rubber as shown in FIG. As shown in FIG. 8, the biaxial loading tester has a base 52 and a cross yoke 53 whose both ends in the direction perpendicular to the paper are fixed to a support frame (not shown). For example, four hydraulic cylinders 54 are provided, and a load yoke 56 is connected to a ram rod of the hydraulic cylinder 54 via a ball seat (not shown). The left and right ends (both ends in the vertical direction of the paper) of the load yoke 56 are supported by a support frame (not shown) via a vertical slide guide. An upper platen 59 is provided on the lower surface of the load yoke 56 via a slide bearing 58 so as to be movable in the horizontal direction. An upper platen 60 is provided on a lower surface of the upper platen 59. Base 5
2 has a lower platen 6 through a horizontal slide bearing 61.
2 is provided, and a lower surface plate 63 is provided on the upper surface of the lower platen 62. The specimen 51 made of seismic isolation rubber is fixed to the upper and lower panels 60 and 63 with bolts and nuts. The upper and lower platens 59 and 62 are moved by the horizontal slide bearings 58 and 61 in the horizontal direction of FIG.

The upper and lower platens 59 and 62 are provided with brackets 64 and 65, respectively.
4, 65 are connected to both ends of a horizontal load hydraulic cylinder 66.
The distance between 4, 65 changes.

Then, the upper platen 59 is pushed vertically by the load yoke 56 to apply a compressive load to the specimen 51. In this state, the hydraulic cylinder 66 is expanded and contracted to move the upper and lower platens 59 and 62 horizontally. Reciprocate relatively. At this time, the displacement amount of the hydraulic cylinder 66 is measured by a displacement meter, and the load load is measured by a load cell provided on the load yoke 56, and the energy curve in which the horizontal axis represents the horizontal movement amount and the vertical axis represents the load cell output. Draw and evaluate the energy loss due to the shear deformation of the specimen 51 from the area of the energy curve.

At this time, each of the vertical load hydraulic cylinders 54 is controlled by load feedback so that the actual load becomes the target load or by displacement feedback such that the actual shaft displacement becomes the target displacement. . Here, since each hydraulic cylinder 54 equally divides the compressive load applied to the specimen 51, the target load of each hydraulic cylinder 54 is １ ／ or 1 of the compressive load according to the number of hydraulic cylinders 54.
/ 4.

[0006]

As described above, when the load feedback control of the hydraulic cylinder is performed, the load generated by the plurality of compression hydraulic cylinders is controlled to a target value, but the displacement varies, so that the horizontal displacement is varied. When the diameter becomes large, the upper platen may be greatly inclined. On the other hand, in the case of displacement feedback control, the displacements of the plurality of compression hydraulic cylinders are respectively controlled to target values, but the load varies due to the displacement of the vibration isolating rubber in the horizontal direction,
An unbalanced load is generated on the upper platen, and the upper platen or other mechanisms may be deformed.

An object of the present invention is to provide a material testing machine and a biaxial loading testing machine in which the displacements and loads of a plurality of actuators which are commonly connected to each other and load a specimen are made uniform. .

[0008]

[Means for Solving the Problems]

(1) Referring to FIGS. 1 to 3 showing one embodiment, the invention of claim 1 is driven by supply and discharge of pressure oil to and from a first port and a second port. A plurality of load actuators 4a to 4 that load via a common jig
d, detectors 6a to 6d, 12a to 12d for detecting the load or displacement acting on the specimen W, and the detectors 6a to 6d
d, and applied to a material testing machine having feedback control circuits 20A to 20D for controlling the load actuators 4a to 4d by displacement feedback control or load feedback control based on the displacements or loads detected by the 12a to 12d. . The above-described object is to provide the first and second oil passages 3 that connect the first ports and the second ports of the load actuators 4a to 4d, respectively.
This is achieved by providing 1a to 31d, 32a to 32d, and valves 33a to 33d that open and close these oil passages to shut off communication between the first ports and to shut off communication between the second ports. (2) Referring to FIGS. 1 to 3 showing one embodiment, the invention of claim 2 is directed to a first to a first method for applying an axial force to the specimen W held by the pair of upper and lower platens 8 and 10. A fourth load actuator 4a to 4d, and a shear force loading mechanism that relatively moves the pair of upper and lower platens 8, 10 and applies a shear force orthogonal to the axial force while applying the axial force to the specimen W. ,
Detectors 6a to 6d and 12a to 12d for detecting an axial load or an axial displacement acting on the specimen W;
6d and 12a to 12d, the load actuators 4a to 4d
Control circuits 20A to 20A for controlling the drive by displacement feedback control or load feedback control
D and is applied to a biaxial loading tester equipped with The above-described object is to provide an oil passage 31 for connecting the first port and the second port of each of the load actuators 4a to 4d.
a to 31d, 32a to 32d, and 34 to 37 respectively open and close the first and second oil passages to cut off communication between the first ports and cut off communication between the second ports. First to fourth valves 33 arranged corresponding to
a to 33d, the first and second load actuators 4a and 4b arranged in the shear direction, and the third
When the first and second load actuators 4c and 4d are first and second actuator sets, respectively, the first port and the second port communicate with each other between the first and second actuator sets. Fifth valve 3 to shut off
8 is achieved.

In the meantime, in the section of the means for solving the above-mentioned problem which explains the constitution of the present invention, the drawings of the embodiments of the present invention are used in order to make the present invention easy to understand. However, the present invention is not limited to this.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
An embodiment applied to a shaft loading test machine will be described. FIGS. 1 and 2 are diagrams showing a schematic configuration of the biaxial loading tester shown in FIG.

As shown in FIGS. 1 and 2, a biaxial loading tester according to the present embodiment comprises four return-type load hydraulic cylinders 4 provided on an upper cross yoke 2 of a frame 1.
a to 4d (the hydraulic cylinder 54 in FIG. 8). 4
The load yoke 7 (see FIG. 8) is connected to the distal ends of the piston rods of the load hydraulic cylinders 4a to 4d via ball seats 5a to 5d (5c and 5d are not shown) and load cells 6a to 6d (6c and 6d are not shown). The load yoke 56) is connected and mounted. That is, the load hydraulic cylinders 4a to 4d are configured to load the specimen W with the common jig 7. The load yoke 7 is provided with a load upper platen 8 (load platen 59 in FIG. 8) via a horizontal reciprocating mechanism (not shown), and the base 9 (base 52 in FIG. 8) via a horizontal reciprocating mechanism (not shown). A load pressure platen 10 (load pressure plate 62 in FIG. 8) is provided. A specimen W is mounted between the load upper and lower platens 8 and 10. The load upper platen 8 and the load lower platen 10 include:
Both ends of a horizontal load hydraulic cylinder (not shown) (horizontal load hydraulic cylinder 66 in FIG. 8) are connected to each other, and a shear force is applied to the specimen W by expansion and contraction of the horizontal load hydraulic cylinder.
A shear force loading mechanism is constituted by the load vertical platens 8, 10 and a horizontal hydraulic cylinder.

FIG. 3 shows a control circuit of the biaxial loading tester according to the present embodiment. In FIG. 3, the load hydraulic cylinder 4
a to 4d are driven by servo valves 4aV to 4dV, respectively, and the servo valves 4aV to 4dV are controlled by first to fourth controllers 20A to 20D, respectively. First to first
The fourth controllers 20A to 20D are feedback circuits that perform load feedback control or displacement feedback control of the load hydraulic cylinders 4a to 4d, respectively, and are common to all. Here, the first controller 20A will be described.

In FIG. 3, a displacement meter 12a detects a displacement of a piston rod of a load hydraulic cylinder 4a and outputs a displacement feedback signal FS. The displacement detected by the displacement meter 12a is representative of the displacement of the specimen W. The displacement of the specimen W may be directly detected and replaced with the signal of the displacement meter 12a. The displacement signal FS is amplified by the displacement amplifier 21. The load cell 6a detects the load applied to the specimen W by the load hydraulic cylinder 4a and outputs a load feedback signal FL. This load feedback signal FL is amplified by the amplifier 22. The setting signal output unit 23 outputs a target displacement signal during displacement feedback control or a target load signal during load feedback control. These target signals can be arbitrarily set by the operator according to the test conditions. Switch 24
Is used to select one of the displacement feedback signal FS and the load feedback signal FL, and the contacts a and b are switched by the operator. The deviation between the target load signal and the load feedback signal FL or the deviation between the target displacement signal and the displacement feedback signal FS is calculated by the deviation unit 25, and the deviation signal is amplified by the servo amplifier 26 and supplied to the servo valve 4aV of the hydraulic cylinder 4a. You. Servo valve 4
Pressure oil is supplied to aV from a control hydraulic circuit (not shown), and the pressure oil is controlled by the servo valve 4aV according to the deviation signal, whereby the load hydraulic cylinder 4a is operated. The other servo valves 4bV to 4dV are similarly driven, and the load hydraulic cylinders 4b to 4d are operated by load feedback or displacement feedback.

A first pipe 31a and a second pipe 32a are respectively connected to the first port and the second port of the load hydraulic cylinder 4a. The first and second ports of the other load hydraulic cylinders 4b to 4d also have first and second pipes 31b to 31d and 32b to 32d, respectively.
d are respectively connected. First piping 31a to 31
d and the second pipes 32a to 32d are connected to the first to fourth electromagnetic on-off valves 33a to 33d via connection pipes 34 to 37, respectively, and the connection pipes 34 and 37 and the pipes 35 and 3 are connected.
Numerals 6 are connected via a fifth electromagnetic on-off valve 38, respectively.

The personal computer 40 sets a common setting signal for each of the setting signal output devices 23 of the first to fourth controllers 20A to 20D, and sets the first to fifth electromagnetic on-off valves 33a to 33d and Sequencer 4 for opening and closing 38
Control via 1. The personal computer 40 also switches the switch 24.

The operation of this embodiment will be described with respect to displacement feedback control. Prior to the test, a personal computer 40
Thus, a predetermined target displacement signal waveform is set in each setting signal output device 23, and the switch 24 is switched to the contact a side. These operations are performed based on a command input by an operator from an input unit (not shown). Switch 2
4 is switched to the contact a side to interlock with the selection of the displacement feedback control, the first to fourth electromagnetic on-off valves 33a to 33d are automatically opened, and the fifth electromagnetic on-off valve is opened. 38 is closed. In addition, the electromagnetic on-off valves 33a to 33d
And 38 may be manually controlled.

When the test is started, a target displacement signal is output from the setting signal output unit 23. When the displacement feedback signal FS is input to the deviation device 25 via the switching device 24,
The deviation between the displacement feedback signal FS and the target displacement is calculated by the deviation unit 25, and the servo valves 4aV to 4dV are loaded hydraulic cylinders 4a to 4d such that the deviation between them becomes zero.
Drive. The load hydraulic cylinders 4a to 4d operate according to the target displacement signal, and the load yoke 7 moves up and down. Therefore, the specimen W is loaded by the displacement feedback control in accordance with the target displacement output from the setting signal output device 23. Although a detailed description is omitted, an axial force is applied to the specimen W, and at the same time, a shear force is applied by a shear force loading mechanism including a horizontal load hydraulic cylinder (not shown).

Here, the case where the load applied by each of the load hydraulic cylinders 4a to 4d is different during the displacement feedback control will be described. FIG. 4 is a schematic perspective view of a main part of the biaxial loading test machine shown in FIGS. As can be seen from FIG. 4, the specimen W has four load hydraulic cylinders 4a to 4d.
, The shear force F1 or F2 is alternately applied by a shear force loading mechanism (not shown). A set of load actuators of the load hydraulic cylinders 4a and 4b and a set of load actuators of the load hydraulic cylinders 4c and 4d are arranged at a predetermined distance in the shear direction. Although the specimen W is deformed by the shearing force as shown in FIG. 5, in the displacement feedback control, each of the load hydraulic cylinders 4a to 4d is feedback-controlled by the same target displacement signal, and their displacement amounts are the same.
Here, if all of the first to fourth on-off valves 33a to 33d are closed, the load applied by the load hydraulic cylinders 4b and 4d is reduced by the deformation of the specimen W.
c, the load becomes smaller, the axial force fluctuates between the hydraulic cylinders, and the load of the load yoke 7 varies.

Therefore, as described above, by opening the first to fourth on-off valves 33a to 33d and closing the fifth on-off valve 38, the first ports of the load hydraulic cylinders 4a and 4b are connected to each other. The second ports are communicated with each other, the first ports of the load hydraulic cylinders 4c and 4d are communicated with the second ports, and the load hydraulic cylinders 4a and 4b are at the same pressure. And 4d are driven at the same pressure. For this reason, the loads applied to the specimen W by the load hydraulic cylinders 4a and 4b are equal to each other even though the displacement feedback control is performed.
The loads applied to the specimen W at c and 4d are equal to each other. As a result, variations in the load generated on the load yoke 7 and the like are suppressed, and damage to the devices and mechanisms is prevented. Further, even if an abnormality occurs in one of the load hydraulic cylinders, the piston is expanded and contracted by the pressure of the other load hydraulic cylinder, so that the load yoke 7 is prevented from being tilted or damaged.

Next, the operation of the present embodiment will be described with respect to load feedback control. Prior to the test, a predetermined target load signal waveform is set from the personal computer 40 to each setting signal output device 23, and the switching device 24 is switched to the contact b side. These operations are performed based on a command input by an operator from an input unit (not shown). Further, in conjunction with the switching of the switch 24 to the contact b side to select the load feedback control, the first to fourth electromagnetic on-off valves 33a to 33d and the fifth electromagnetic on-off valve Valve 3
8 is opened. In this case, as described above, the opening and closing control of the electromagnetic on-off valves 33a to 33d and 38 may be manually performed.

When the test is started, a target load signal is output from the setting signal output device 23. When the load feedback signal FL is input to the deviation device 25 via the switch 24,
The deviation between the load feedback signal FL and the target load is calculated by the deviation unit 25, and the servo valves 4aV to 4dV are loaded hydraulic cylinders 4a to 4d such that the deviation between them becomes zero.
Drive. The load hydraulic cylinders 4a to 4d operate according to the target load signal, and the load yoke 7 moves in the vertical direction. Therefore, the specimen W is loaded by the load feedback control in accordance with the target load output from the setting signal output device 23. Although a detailed description is omitted, at the same time as applying an axial force to the specimen W, a shear force is also applied by a shear force application mechanism (not shown).

Here, a case where the displacement amounts of the load hydraulic cylinders 4a to 4d are different during the load feedback control will be described. The specimen W tends to deform as shown in FIG. 5 due to the shearing force. In the load feedback control, each of the load hydraulic cylinders 4a to 4d is feedback-controlled by the same target load signal, and their loads become the same. Here, if all of the first to fourth on-off valves 4a to 4d are closed, the displacement of the load hydraulic cylinders 4b and 4d is larger than the displacement of the load hydraulic cylinders 4a and 4c due to the deformation of the specimen W. As a result, the load yoke 7 is inclined as shown in FIG.

Therefore, as described above, when the first to fourth on-off valves 33a to 33d and the fifth on-off valve 38 are opened, the first ports of the load hydraulic cylinders 4a to 4d are connected to the second port. Since the ports communicate with each other, the load hydraulic cylinder 4
a to 4d are driven at the same pressure. With this, the load hydraulic cylinders 4a to 4a
The displacement amounts of d become equal, and the inclination of the load yoke 7 is prevented. Incidentally, in this case, the first to fourth on-off valves 33a to 33a to
The displacement amount of the four load hydraulic cylinders 4a to 4d is larger than the minimum displacement amount when the 33d is closed. Further, similarly to the displacement feedback control, even if an abnormality occurs in one load hydraulic cylinder, the piston is expanded and contracted by the pressure of another load hydraulic cylinder, so that the inclination and breakage of the load yoke 7 are prevented.

Although the displacement feedback control and the load feedback control have been described above, when the specimen W is mounted between the load platens 8 and 10, the upper platen 8 must be manually operated.
The hydraulic cylinder is driven by so-called large displacement control. In this case, similarly to the load feedback control, the first to fourth on-off valves 33a to 33d and the fifth on-off valve 38 are opened. Thereby, the load hydraulic cylinders 4a to 4d
Are all controlled at the same pressure, and there is no possibility that a variation in load occurs in the load yoke 7 when the specimen W is installed.

In FIG. 3, the first to fourth controllers 20
A to 20D are common, and the same target signal is set from the personal computer 40 to each setting signal output device 23.
For example, the load hydraulic cylinders 4a and 4b may be a set of load actuators, and the load hydraulic cylinders 4c and 4d may be a set of load actuators, and each set may be controlled by a common feedback circuit. in this case,
Since the displacement feedback control is performed by the two systems, the fifth on-off valve 38 is closed, and the first to fourth on-off valves 33a to 33d are closed.
Open. FIG. 7 shows a block diagram in such a case. The same parts as those in FIG. 3 are denoted by the same reference numerals, and differences will be mainly described.

In the circuit shown in FIG. 7, the displacement of both the load hydraulic cylinders 4a and 4b is fed back by the displacement of the load hydraulic cylinder 4a detected by the displacement meter 12a.
The displacement of both the load hydraulic cylinders 4c and 4d is fed back based on the displacement of the load hydraulic cylinder 4c detected by c, and the load obtained by adding the load by the load hydraulic cylinders 4a and 4b detected by the load cells 6a and 6b by the adder 41a. The load signal is fed back to the load hydraulic cylinders 4a and 4b by the feedback signal FL, and the load feedback signal FL obtained by adding the load by the load hydraulic cylinders 4c and 4d detected by the load cells 6c and 6d by the adder 41c.
, The load hydraulic cylinders 4c and 4d are fed back.

The present invention can be applied to a simple compression tester. In this case, if the specimen W is a fragile material such as concrete, the fifth on-off valve 38 can be used even if the displacement feedback control is performed. It is preferable to keep it open. Since the state of compressive failure of the concrete specimen is not uniform, all load hydraulic cylinders 4a
4d are driven at the same pressure.

In the above, the biaxial loading tester has been described. However, the present invention is not limited to this, and various types of material testers in which a plurality of actuators load a specimen through a common jig. Applicable.

[0029]

【The invention's effect】

(1) As described above, according to the present invention, if the first and second ports of the plurality of load hydraulic cylinders are communicated with each other to perform the displacement feedback, the load loads by the respective load hydraulic cylinders are equalized and the displacement feedback is performed. Control can be performed. As a result, load variations do not occur on the platen or the like, and damage to equipment and mechanisms can be prevented.
Further, if the first and second ports of the plurality of load hydraulic cylinders are communicated with each other to perform load feedback, the load feedback control can be performed by equalizing the displacement of each load hydraulic cylinder. As a result, the platen or the like does not tilt, and damage to equipment and mechanisms can be prevented. Furthermore, even if an abnormality occurs in one load hydraulic cylinder, the piston expands and contracts with the pressure of the other load hydraulic cylinder,
Tilt and breakage of the platen and the like are prevented. (2) In particular, according to the second aspect of the present invention, when applying the present invention to a biaxial loading tester, a pair of hydraulic cylinders arranged in the shear direction is regarded as one set, and a total of two sets of load hydraulic cylinders are used. Load feedback control or displacement feedback control is performed for each load hydraulic cylinder, and the first and second ports of each set of load hydraulic cylinders communicate with each other. , The displacement feedback control can be performed by equalizing the load applied by the load, the load does not fluctuate in the load yoke and the like, and the device and mechanism can be prevented from being damaged. Further, the load feedback control can be performed by equalizing the displacements of the load hydraulic cylinders, the platen and the like do not tilt, and the equipment and mechanism can be prevented from being damaged.

[Brief description of the drawings]

FIG. 1 is a schematic front view showing a configuration of a material testing machine according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a block diagram showing a control circuit according to the embodiment of the present invention.

FIG. 4 is a schematic perspective view of the biaxial loading test machine shown in FIG.

FIG. 5 is a diagram for explaining the behavior of a specimen during displacement feedback.

FIG. 6 is a view for explaining the behavior of a test specimen at the time of load feedback.

FIG. 7 is a block diagram showing a control circuit according to another embodiment of the present invention.

FIG. 8 is a schematic configuration diagram of a biaxial loading tester for explaining a conventional problem.

[Explanation of symbols]

 4a to 4d Load hydraulic cylinder 4aV to 4dV Servo valve 6a to 6d Load cell 7 Load yoke 20A to 20D First to fourth controller 23 Setting signal output device 24 Switching device 25 Deflector 33a to 33d First to fourth opening / closing valve 38 Fifth on-off valve W Specimen

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-218408 (JP, A) JP-A-8-101108 (JP, A) JP-A-10-332563 (JP, A) JP-A-11- 37912 (JP, A) JP-A-11-83714 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01N 3/00-3/62 G05D 16/02 JICST file (JOIS)

Claims (2)

(57) [Claims] 1. A plurality of load actuators driven by supply and discharge of pressure oil to and from a first port and a second port to load a specimen through a common jig, and a load or displacement acting on the specimen. A material testing machine comprising: a detector to detect; and a feedback control circuit that drives and controls the load actuator by displacement feedback control or load feedback control based on the displacement or load detected by the detector. First and second oil passages connecting the first port and the second port of the load actuator, respectively, and opening and closing these oil passages to cut off communication between the first ports; A material testing machine driven by a plurality of actuators, comprising: a valve for communicating and shutting off the second ports. 2. A first to a fourth load actuators, which are held by a pair of upper and lower platens and apply an axial force to a specimen, and the pair of upper and lower platens are relatively moved while an axial force is applied to the specimen. A shear force loading mechanism for moving and repeatedly applying a shear force orthogonal to the axial force; a detector for detecting an axial load or an axial displacement acting on the specimen; and an axial displacement detected by the detector. Or a feedback control circuit that drives and controls the load actuator based on an axial load by displacement feedback control or load feedback control. The first of the first to fourth load actuators includes: First and second oil passages for connecting the ports and the second port, respectively, for opening and closing the first and second oil passages, respectively; And the first and second valves arranged to correspond to each port, and the first and second load actuators arranged in the shearing direction. Similarly, when the third and fourth load actuators arranged in the shear direction are respectively a first and a second actuator set, the first ports and the first port are connected between the first and the second actuator sets. A two-axis loading test machine, comprising: a fifth valve that connects and disconnects two ports from each other.