JP2013092413A - Biaxial test device and biaxial test method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a test piece from deforming in a direction other than biaxial directions of expansion and contraction with a simple configuration.SOLUTION: A biaxial test device includes: a load transmission mechanism 8 which causes a load in a direction orthogonal to a load in a uniaxial direction to act on a test piece 7 in a stage, in which pairs of tool plates 4a, 4b and 5a, 5b approaching and separating from each other in a uniaxial direction in association with an operation of an actuator 3 and a support plate are arranged on both sides across the test piece 7, and the uniaxial load is placed on the test piece 7 by coupling the tool plate, support plate part, and test piece 7 separably to one another, and then activating the tool plates and support plate part; and slide guide means 20 for guiding a uniaxial movement of an edge 19 extending in a direction parallel with the uniaxial direction of the respective tool plates and support plate by engaging the edge 19.

Description

  The present invention is used to evaluate mechanical properties under biaxial stress in a thin metal plate material called a membrane used for a liquid natural gas (LNG) transport tank, a storage tank, or the like. The present invention relates to an axial test apparatus and a biaxial test method.

  A membrane used for a tank of liquefied natural gas or the like is provided with a plurality of corrugated portions called corrugations. Since the membrane is manufactured at room temperature and then used at an extremely low temperature of, for example, −162 ° C., the membrane is always used under severe conditions where a tensile load and a compressive load act repeatedly. In addition to basic requirements such as heat resistance, heat resistance and low temperature toughness, it is also necessary to be able to meet strict requirements for fatigue damage due to thermal cycles and fluid pressure fluctuations.

  Among these requirements for membranes, evaluation of fatigue strength is important. Therefore, the first to fourth link sets that connect adjacent corner portions of the test piece having a substantially rectangular plate shape are provided, and the load in the biaxial direction is obtained by pulling the test piece in all directions by each link set. There is a biaxial test apparatus which is applied to a test piece (Patent Document 1).

JP 2010-210442 A

  However, in the biaxial test apparatus of Patent Document 1, the first to fourth link sets that connect adjacent corner portions of the test piece are provided, and the test piece is pulled in all directions by each link set. Therefore, the structure for the link set becomes complicated, and it is necessary to provide four actuators for pulling the test piece in all directions, which causes a problem that the entire test apparatus becomes large.

  The present invention has been made in view of the above-described conventional problems, and a biaxial test apparatus and a biaxial test apparatus capable of preventing the test piece from being deformed in a direction other than expansion and contraction in the biaxial direction with a simple configuration. An attempt is made to provide an axial test method.

  In the present invention, a pair of load-loading portions that approach and separate in one axial direction by the operation of an actuator are arranged on both sides of a test piece, and the load-loading portion and the test piece are detachably coupled to each other and the load-loading portion is A load transmission mechanism that applies a load in a direction orthogonal to the uniaxial load to the test piece when the uniaxial load is applied to the test piece, and the uniaxial direction in each load load portion The present invention relates to a biaxial testing apparatus comprising a slide guide means that engages with an edge extending in a direction parallel to the edge and guides movement of the edge in one axial direction.

  In the biaxial testing apparatus, the slide guide means includes a moving piece fixed to an end edge of each load-loading portion, and a rail slidably engaged with each moving piece and fixed to the guide beam. It is preferable.

  In the biaxial testing apparatus, the load transmission mechanism may include a pin provided in one of the pair of load load portions spaced apart in a direction perpendicular to the uniaxial direction, and a pair of load load portions. And a slide hole provided in the test piece and slidably engaged with the pin, the uniaxial direction in the test piece. In order to apply a load in a direction perpendicular to the uniaxial load to the test piece when the load is applied, it is preferable that the slide hole is formed obliquely with respect to the load application direction.

The present invention is a biaxial test method used for evaluating mechanical properties of a test piece under biaxial stress,
A pair of load-loading parts approaching and separating in a uniaxial direction are arranged on both sides of the test piece, and one load-loading part of the pair of load-loading parts is provided with a pin separated in a direction perpendicular to the uniaxial direction. In addition, the other load load portion of the pair of load load portions is provided with a pin separated in a direction orthogonal to the uniaxial direction,
The test piece is formed with an oblique slide hole with respect to the direction in which the load is slidably engaged with the pin,
Provided is a slide guide means composed of a moving piece fixed to an edge extending in a direction parallel to the uniaxial direction in each load applying portion and a rail engaged with the moving piece and fixed to a guide beam.
At the stage where the pair of load-loading portions are moved closer to and away from each other in the uniaxial direction and a uniaxial load is applied to the test piece, a load perpendicular to the uniaxial load is applied to the test piece. Is suppressed by the load-loading portions disposed on both sides of the test piece, and the sliding means suppresses the uneven extension deformation that projects outwardly from the surface of the test piece. This relates to a characteristic biaxial test method.

  According to the biaxial test apparatus and the biaxial test method of the present invention, with a simple configuration, the test piece is prevented from being deformed in directions other than expansion and contraction in the biaxial direction, and accurate performance measurement by the test piece is performed. It is possible to achieve an excellent effect that becomes possible.

It is a front view which shows one Example of the biaxial testing apparatus based on this invention. It is the side view of the biaxial testing apparatus which looked at FIG. 1 from the II-II direction. It is the rear view of the biaxial test device which looked at Drawing 2 from the III-III direction. It is a top view which shows an example of a slide guide means. (A) is a front view which shows an example of the test piece used with the biaxial testing apparatus of this invention, (b) is a VV direction arrow line view of (a). FIG. 5A is an operation diagram showing a state in which the test piece is about to be deformed in an uniaxial direction when the test piece of FIG. 5 is pulled in a uniaxial direction, and FIG. It is an action | operation figure which shows the state which is going to produce a deformation | transformation. It is the graph which measured and showed the displacement between the vertical and horizontal gauge marks of the test piece tested with the biaxial testing device of the present invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  The biaxial test apparatus 1 shown in FIGS. 1 to 3 includes a base 2 fixed to a fixed base and the like, and a push-pull rod 3a. The push-pull rod 3a is placed on the machine axis L in the vertical direction (uniaxial direction). And two jig plates (one of a pair of load-loading portions) fixed to the base 2 with a left-right space around the axis L and the actuator 3 disposed above the base 2. (Load load portions) 4a, 4b and two jig plates (the other load load portion of the pair of load load portions) fixed to the push / pull rod 3a of the actuator 3 via the support beam 6 with a spacing left and right. ) 5a, 5b and a load transmission mechanism 8 for detachably connecting the jig plates 4a, 4b, 5a, 5b and the test piece 7 to each other.

  FIG. 5 shows an example of the test piece 7 constituting the membrane. In the test piece 7 of FIG. 5, a corrugated portion 9 called corrugation intersects a surface of a thin metal plate such as stainless steel having a rectangular shape. In addition, a bulging portion 10 is formed at the intersecting portion of the corrugated portion 9, and the test piece 7 can be expanded and contracted in the surface direction. Slide holes 12a, 12b, 12c and 12d are formed in flat portions 11 at the four corners where the corrugated portion 9 of the test piece 7 does not exist.

  Pins 13a, 13b, 13c, 13d that are slidably engaged with the slide holes 12a, 12b, 12c, 12d of the test piece 7 are fixed to the jig plates 4a, 4b, 5a, 5b. The load transmission mechanism 8 is configured by engaging the slide holes 12a, 12b, 12c, and 12d with the pins 13a, 13b, 13c, and 13d.

  Further, on the back side of the jig plates 4a, 4b, 5a, 5b in FIG. 1, the test piece 7 is placed between the jig plates 4a, 4b, 5a, 5b as shown in FIGS. A pair of support plates 14 a, 14 b, 15 a, 15 b are arranged so as to be sandwiched, the support plates 14 a, 14 b are fixed to the base 2, and the support plates 15 a, 15 b are fixed to the upper support beam 6. The jig plates 4a, 4b, 5a, 5b and the support plates 14a, 14b, 15a, 15b are arranged close enough not to restrain the expansion and contraction of the test piece 7, and the reinforcing ribs 16 are respectively provided. The strength is maintained.

  Further, as shown in FIG. 3, the support plates 14 a, 14 b, 15 a, and 15 b are provided with an extension portion 17 that projects to the back surface of the corrugated portion 9 and the bulging portion 10 of the test piece 7. The effect which suppresses that the said test piece 7 deform | transforms out of plane is heightened.

  Further, since the back surface of the test piece 7 where the corrugated portion 9 does not exist is a flat surface, instead of providing the support plates 14a, 14b, 15a, 15b, the support plates 14a, 14b are integrated, Alternatively, the support plates 15a and 15b may be integrated, and a pair of the test pieces 7 each having a length extending across the left and right width may be provided.

  The slide holes 12a and 12b that engage with the pins 13a and 13b on the base 2 side constituting the load transmission mechanism 8 have a load application direction (vertical) so that the distance between the upper ends is wider than the distance between the lower ends. On the other hand, the slide holes 12c and 12d engaged with the pins 13c and 13d on the actuator 3 side are formed so that the distance between the lower ends is wider than the distance between the upper ends. It is formed diagonally. The inclination angle at which the slide holes 12a, 12b, 12c, and 12d are inclined can be set to 45 ° with respect to the machine axis L (load application direction). Further, the slide holes 12a, 12b, 12c, 12d inclined obliquely may be straight as shown in FIG. 5, or may be curved. In FIG. 1, the pins 13 a, 13 b, 13 c, and 13 d constituting the load transmission mechanism 8 are shown as being provided with two pins, but may be provided one by one. It is not limited. The pins 13a, 13b, 13c, 13d may be supported by one of the jig plates 4a, 4b, 5a, 5b and the support plates 14a, 14b, 15a, 15b, or both. May be.

  When the push-pull rod 3 a is pulled up by causing the actuator 3 of the biaxial test apparatus 1 of FIG. 1 to pull up, the tensile load of the actuator 3 is transmitted to the test piece 7 via the load transmission mechanism 8. In addition, a tensile load in the vertical direction (uniaxial direction) acts on the test piece 7, and at the same time, due to the action of the slide holes 12a, 12b, 12c, 12d and the pins 13a, 13b, 13c, 13d of the load transmission mechanism 8. A tensile load in a direction orthogonal to the uniaxial direction acts on the test piece 7.

  At this time, as shown in FIG. 6 (a), when a tensile load A is applied to the test piece 7, the flat end portion 11 of the width end portion 18 side is likely to generate a partial elongation deformation X in which the portion extends in a tensile direction. And This partial deformation X occurs when the width end portion side of the corrugated portion 9 having a small strength provided on the left and right is biased and stretched. At the same time, as shown in FIG. 6B, the test piece 7 tends to generate an out-of-plane deformation Y that curves out of the plane of the test piece 7 due to the presence of the corrugated portion 9.

  At this time, as described above, since the jig plates 4a, 4b, 5a, 5b and the support plates 14a, 14b, 15a, 15b are arranged on both sides of the test piece 7, the test piece shown in FIG. 7 is suppressed by the jig plates 4a, 4b, 5a, 5b and the support plates 14a, 14b, 15a, 15b.

  On the other hand, it is not possible to constrain the uneven elongation deformation X shown in FIG.

  Therefore, in the present invention, as shown in FIG. 1, the outer edges of the jig plates 4a, 4b, 5a, 5b and the support plates 14a, 14b, 15a, 15b extending in the direction parallel to the uniaxial direction are further outside. An end edge 19 is provided, and slide guide means 20 is provided for guiding the end edge 19 so as to move in one axial direction.

  As shown in FIGS. 1 and 4, the slide guide means 20 has a moving piece 22 on a flange 21 provided on the edge 19 of the jig plates 4a, 4b, 5a, 5b and the support plates 14a, 14b, 15a, 15b. , And a rail 23 slidably engaged with each moving piece 22 is fixed to the guide beam 24. The guide beam 24 is suspended from the jig plates 5a and 5b by placing a bracket 25 provided at the upper end on the upper end of the flange 21 of the upper jig plates 5a and 5b.

  Next, the operation of the biaxial testing apparatus will be described.

  First, in the setup stage, jig plates 4a and 4b constituting one of the pair of load loading portions are fixed to the base 2, and jig plates 5a and 5b constituting the other of the pair of load loading portions. Is fixed to the upper support beam 6, and the actuator 3 is operated to move the jig plates 5a, 5b upward, thereby adjusting the distance between the pair of upper and lower jig plates 4a, 4b, 5a, 5b.

  Subsequently, the test piece 7 is placed so that the flat portion 11 of the surface on which the corrugated portion 9 protrudes in the test piece 7 of FIG. 5 corresponds to the back surface of the jig plates 4a, 4b, 5a, 5b of FIG. The slide holes 12a, 12b, 12c, and 12d provided in the test piece 7 are engaged with pins 13a, 13b, 13c, and 13d provided on the jig plates 4a, 4b, 5a, and 5b.

  Subsequently, the support plates 14a, 14b, 15a, 15b are arranged so as to sandwich the test piece 7 arranged on the back surface of the jig plates 4a, 4b, 5a, 5b, and the support plates 14a, 14b are fixed to the base 2. The support plates 15a and 15b are fixed to the upper support beam 6.

  Next, the moving piece 22 is fixed to the flange 21 provided on the edge 19 of the jig plates 4a, 4b, 5a, 5b and the support plates 14a, 14b, 15a, 15b, and each moving piece 22 is slidable. The rail 23 to be engaged is fixed to the guide beam 24, and a bracket 25 provided at the upper end of the guide beam 24 is placed on the upper end of the flange 21 of the upper jig plates 5a and 5b and suspended to slide guide means. 20 is configured.

  In order to perform the biaxial test, the actuator 3 of the biaxial testing apparatus 1 in FIG. Then, the tensile load of the actuator 3 is transmitted to the test piece 7 via the load transmission mechanism 8, and a tensile load in the vertical direction (uniaxial direction) acts on the test piece 7, and at the same time, the slide hole 12 a of the load transmission mechanism 8. , 12b, 12c, 12d and the pins 13a, 13b, 13c, 13d, a tensile load acts in a direction orthogonal to the uniaxial direction (the other uniaxial direction), thereby performing a biaxial test. At this time, if the inclination angle of the slide holes 12a, 12b, 12c, and 12d is 45 °, the extension amount of the test piece 7 extending in the uniaxial direction is equal to the extension amount in the direction orthogonal to the uniaxial direction. . Therefore, by changing the inclination angle from 45 °, the test piece 7 can be tested in a state where the amount of elongation of the test piece 7 extending in the uniaxial direction and the amount of elongation (elongation ratio) in the direction orthogonal to the uniaxial direction are changed. it can. The actuator 3 repeatedly pulls, returns, and compresses the test piece 7, and at this time, tests are performed using sensors such as strain gauges, displacement meters (velocimeters, accelerometers) and the like installed at necessary locations of the test piece. The displacement between the gauge points at each location of the piece 7 is measured, and further, the number of repetitions until the test piece 7 is destroyed by repeatedly applying a load in accordance with the actual machine is examined. The mechanical properties such as fatigue strength can be evaluated.

  As described above, when a tensile load is applied to the test piece 7, the test piece 7 tends to generate an out-of-plane deformation Y that is deformed into a convex shape or a concave shape outside the surface by the tensile load A as shown in FIG. .

  However, since the biaxial test apparatus 1 includes jig plates 4a, 4b, 5a, and 5b and support plates 14a, 14b, 15a, and 15b so as to sandwich the test piece 7, the test piece 7 is out of plane. The deformation Y can be prevented satisfactorily.

  Further, as described above, when a tensile load is applied to the test piece 7, as shown in FIG. 6A, the flat end portion 11 will have a partial elongation deformation X in which the width end portion 18 side is elongated in the tensile direction. And

  However, as shown in FIG. 1, the moving piece 22 is fixed to the edge 19 extending in a direction parallel to the uniaxial direction in the jig plates 4a, 4b, 5a, 5b and 14a, 14b, 15a, 15b. Since the slide guide means 20 is provided in which a rail 23 slidably engaged with each moving piece 22 is fixed to the guide beam 24, the jig plates 4a, 4b, 5a, 5b and the support plates 14a, 14b, 15a, 15b moves only in the uniaxial direction along the rail 23, and the biaxial test apparatus 1 as a whole can prevent the test piece 7 from undergoing the partial elongation deformation X.

  FIG. 7 is a graph obtained by measuring the displacement between the vertical and horizontal test points of the test piece by the biaxial test apparatus of the present invention. The present invention is a configuration in which a load is applied only in one axial direction by the actuator 3. In FIG. 7, the displacement between the vertical and horizontal gauge points is substantially the same.

  According to the present invention, the displacement between the vertical and horizontal gauge marks substantially coincided with each other because the test piece 7 was uniformly expanded and contracted in the biaxial direction by suppressing the uneven extension deformation X and the out-of-plane deformation Y of the test piece 7. This is thought to be due to this.

  As described above, since the deflection elongation X and the out-of-plane deformation Y of the test piece 7 can be suppressed, the expansion and contraction behavior of the actual machine can be reproduced faithfully to the test piece 7, and thus the test can be performed. Highly accurate test data required for the soundness evaluation of the can be obtained.

  In addition, when the direction of the slite holes 12a, 12b, 12c, and 12d shown in FIG. 1 is changed by 90 degrees to form the slite holes 12a, 12b, 12c, and 12d in a radial manner, the actuator 3 Is transmitted to the test piece 7 via the load transmission mechanism 8, and the tensile load in the vertical direction (uniaxial direction) acts on the test piece 7, and at the same time, the slide holes 12 a, 12 b, 12 c whose orientations have changed are described above. , 12d, a compressive load acts in a direction perpendicular to the uniaxial direction (the other uniaxial direction). This makes it possible to perform a biaxial test of tension and compression.

  The biaxial test apparatus and the biaxial test method of the present invention are not limited to the above-described embodiments. Various test pieces having a corrugated portion such as a thin metal plate such as stainless steel or flat ceramics are not limited. Applicable to biaxial tests, applicable to tests of test pieces with shapes other than those shown, jig plate and support plate shapes, moving pieces and rail shapes can be variously changed, and the present invention Of course, various changes can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Biaxial testing apparatus 3 Actuator 4a, 4b, 5a, 5b Jig plate (a pair of load load parts)
7 Test piece 8 Load transmission mechanism 12a, 12b, 12c, 12d Slite hole 13a, 13b, 13c, 13d Pin 14a, 14b, 15a, 15b Support plate (a pair of load-loading portions)
19 Edge 20 Slide guide means 22 Moving piece 23 Rail 24 Guide beam X Out-of-plane deformation Y Curved deformation

Claims (4)

  A pair of load-loading portions that approach and separate in one axial direction by the operation of the actuator are disposed on both sides of the test piece, and the load-loading portion and the test piece are detachably coupled and the load-loading portion is operated to A direction parallel to the uniaxial direction in each of the load portions is provided with a load transmission mechanism that applies a load in a direction orthogonal to the uniaxial load to the test piece when a uniaxial load is applied to the test piece. A biaxial test apparatus comprising slide guide means for engaging with an end edge extending in the direction and guiding movement of the end edge in one axial direction.   The slide guide means includes a moving piece fixed to an end edge of each load-loading portion and a rail slidably engaged with each moving piece and fixed to a guide beam. 2. The biaxial test apparatus according to 1.   The load transmission mechanism includes a pin provided in one load load portion of the pair of load load portions so as to be separated in a direction orthogonal to the uniaxial direction, and a uniaxial direction of the other load load portion of the pair of load load portions. A pin provided apart in a direction orthogonal to a direction, and a slide hole provided in the test piece, in which the pin is slidably engaged, and in the stage of applying a uniaxial load to the test piece, The biaxial shaft according to claim 1 or 2, wherein the slide hole is formed obliquely with respect to a direction in which the load is applied so that a load in a direction orthogonal to a uniaxial load is applied to the test piece. Test equipment. A biaxial test method used to evaluate mechanical properties of a specimen under biaxial stress,
A pair of load-loading parts approaching and separating in a uniaxial direction are arranged on both sides of the test piece, and one load-loading part of the pair of load-loading parts is provided with a pin separated in a direction perpendicular to the uniaxial direction. In addition, the other load load portion of the pair of load load portions is provided with a pin separated in a direction orthogonal to the uniaxial direction,
The test piece is formed with an oblique slide hole with respect to the direction in which the load is slidably engaged with the pin,
Provided is a slide guide means composed of a moving piece fixed to an edge extending in a direction parallel to the uniaxial direction in each load applying portion and a rail engaged with the moving piece and fixed to a guide beam.
At the stage where the pair of load-loading portions are moved closer to and away from each other in the uniaxial direction and a uniaxial load is applied to the test piece, a load perpendicular to the uniaxial load is applied to the test piece. Is suppressed by the load-loading portions disposed on both sides of the test piece, and the sliding means suppresses the uneven extension deformation that projects outwardly from the surface of the test piece. Characteristic biaxial test method.

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