JP2014106026A - Flexure twisting combined load test method and jig for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bending moment and a twisting moment with a test piece and to make a general-purpose monopodium load testing machine usable.SOLUTION: A test piece 1 is decentered against a pair of chucks of a monopodium load testing machine. Both endpoints of the test piece 1 is held with tips of a pair of moment arms 3, 3 arranged with a phase angle θ being provided for each. By attaching the base end of the pair of moment arms 3, 3 onto a pair of chucks and changing the interval of the pair of chucks, a bending moment M and a twisting moment T are adapted to be simultaneously provided with the test piece 1.

Description

  The present invention relates to a bending torsion composite load test method and a bending torsion composite load test jig for performing a test while simultaneously applying a bending moment and a torsion moment to a test body such as a pipe or a rod-shaped member.

  For example, in order to study the effects of building piping on earthquakes, tubular members (test specimens) may be tested using a uniaxial tensile testing machine. As a tensile tester for a tubular test body, there is one shown in FIG. 7 (Patent Document 1). In this tensile tester, the upper and lower chucks 103 and 103 are eccentric with respect to the upper and lower tensile pedestals 101 and 102, and the test body 104 is attached in an eccentric state with respect to the upper and lower tensile pedestals 101 and 102. . Therefore, a bending stress can be applied to the test body 104 by increasing the distance between the upper and lower mounting bases 101 and 102 and applying a tensile load to the test body 104.

JP 2009-2494136 A

  By the way, the stress acting on the building piping when an earthquake occurs is not limited to bending stress, and torsional stress also acts. However, the above-described tensile testing machine cannot perform a test while simultaneously applying both bending stress and torsional stress to the test body 104.

  The above-described tensile testing machine is a dedicated machine in which the chucks 103 and 103 are eccentric with respect to the upper and lower tensile pedestals 101 and 102, and is expensive and can be used for a normal simple tensile test. Inferior versatility.

  The present invention provides a bending torsion combined load test method and a bending torsion combined load test jig capable of simultaneously applying a bending moment and a torsion moment to a specimen and using a general-purpose uniaxial load tester. The purpose is to provide.

  In order to achieve this object, the bending torsional composite load test method according to claim 1 is characterized in that a test body is decentered with respect to a pair of chucks of a uniaxial load tester and a pair of phase angles are arranged with respect to each other. While holding both ends of the specimen at the tip of the moment arm, the base ends of the pair of moment arms are attached to the pair of chucks, and the bending moment and torsional moment are simultaneously applied to the specimen by changing the distance between the pair of chucks. Is. Therefore, when a uniaxial load (tensile load or compressive load) is applied by a uniaxial load testing machine, a bending moment and a torsional moment are simultaneously applied to the specimen.

  In the bending torsion composite load test method according to claim 2, the length of the pair of moment arms is changed to adjust the magnitude of the bending moment applied to the specimen.

  Further, in the bending torsion composite load test method according to the third aspect, the magnitude of the torsional moment applied to the specimen is adjusted by changing the phase angle of the pair of moment arms.

  Furthermore, the bending and torsional composite load testing jig according to claim 4 includes a pair of moment arms for attaching both ends of the test body to a pair of chucks of a uniaxial load tester, and the pair of moment arms includes a pair of test bodies. They are arranged eccentric with respect to the chuck and at a phase angle with respect to each other.

  In the bending torsion composite load test method according to claim 1, since a bending moment and a torsion moment can be simultaneously applied to the specimen simply by applying a uniaxial load (tensile load or compressive load), it is held by a pair of moment arms. A bending torsion test can be easily performed on a possible specimen. In addition, since there is no need to change the chuck itself, a general-purpose machine can be used as it is as a single-axis load tester (single-axis tensile tester or single-axis compression tester). In comparison, the cost required for the test can be reduced.

  In the bending torsion composite load test method according to claim 2, the magnitude of the bending moment can be adjusted by changing the length of each moment arm, so the magnitude of the bending moment applied to the specimen can be simplified. Can be changed to Therefore, it is easy to repeat the test by changing the magnitude of the bending moment. It is also easy to change the ratio of the magnitude of the bending moment and torsional moment applied to the specimen.

  In the bending torsion composite load test method according to claim 3, the magnitude of the torsional moment can be adjusted by changing the phase angle of each moment arm. Can be changed to Therefore, it is easy to repeat the test by changing the magnitude of the torsional moment. It is also easy to change the ratio of the magnitude of the bending moment and torsional moment applied to the specimen.

  Furthermore, the bending and torsional composite load test jig according to claim 4 includes a pair of moment arms for attaching both ends of the test body to a pair of chucks of a uniaxial load tester, and the pair of moment arms includes the test body. Since it is eccentric with respect to a pair of chucks and arranged at a phase angle, it is possible to simultaneously apply a bending moment and a torsion moment to the specimen simply by applying a uniaxial load (tensile load or compressive load). The bending torsion test can be easily performed on the test body. In addition, since there is no need to change the chuck itself, a general-purpose machine can be used as it is as a single-axis load tester (single-axis tensile tester or single-axis compression tester). In comparison, the cost required for the test can be reduced.

It is a conceptual diagram which shows an example of embodiment of the bending torsion compound load test method of this invention. It is a perspective view which shows an example of embodiment of the bending torsion compound load test jig | tool of this invention. It is sectional drawing of the chuck | zipper of a uniaxial load tester. It is explanatory drawing which showed the relationship of each axis and was seen from the axial direction of the test body. It is explanatory drawing which showed the relationship of each axis and was seen from the front of the test body. It is a figure for demonstrating calculation of the bending moment M and the torsional moment T. FIG. It is a figure which shows the mode of the conventional tension test.

  Hereinafter, the configuration of the present invention will be described in detail based on the form shown in the drawings.

  FIGS. 1-6 shows an example of embodiment of the jig | tool for a bending torsion compound load test of this invention. The uniaxial load test jig includes a pair of moment arms 3 and 3 for attaching both ends of the test body 1 to a pair of chucks 2 and 2 of a uniaxial load tester, and the pair of moment arms 3 and 3 are tested. The body 1 is eccentric with respect to the pair of chucks 2 and 2 and arranged with a phase angle θ.

  In this embodiment, a uniaxial tensile tester is used as a uniaxial load tester. However, the present invention is not limited to this. It is.

  As the test body 1, for example, a round pipe shape, a square pipe shape, a rod shape and the like are preferable, but not limited thereto.

  The base ends of the moment arms 3 and 3 are attached to the chucks 2 and 2 of the single-axis load tester. The chucks 2 and 2 are rotatable around an axis (hereinafter referred to as load axis 4) for applying a uniaxial load to the test body 1 and an axis perpendicular to the load axis 4 (hereinafter referred to as orthogonal axis 5). Is preferred. Thus, by making the chucks 2 and 2 rotatable about the two axes of the load axis 4 and the orthogonal axis 5, the test can be performed without restricting the movement of the test body 1 due to deformation. However, it does not necessarily have to be rotatable around two axes in this way, it may not be rotatable only about one of the axes, and may not be rotatable about both axes. In this case, a bending torsion test can be performed.

  The chucks 2 and 2 of the single-axis load tester of this embodiment are provided with a thrust bearing 6 that enables rotation around the load axis 4 and rotary shafts 7 and 8 that allow rotation around the orthogonal axis 5. The degree of freedom of rotation around the two axes is ensured. That is, the support shaft 10 is provided so as to be rotatable around the load axis 4 via the thrust bearing 6 with respect to the base 9, and the connecting pieces 11, 11 connect the first rotating shaft 7 with respect to the support shaft 10. The second rotary shaft 8 is provided so as to be rotatable around the orthogonal axis 5 with respect to the connecting pieces 11 and 11. The moment arms 3 and 3 are connected to the connecting pieces 11 and 11 by the second rotating shaft 8 so as to be rotatable around the orthogonal axis 5.

  The tips of the moment arms 3 and 3 hold the test body 1. In the present embodiment, the end of the test body 1 is inserted into a holding hole with a slit provided at the tips of the moment arms 3 and 3, and the diameter of the holding hole is narrowed by tightening a bolt to fix the test body 1. The test body 1 is fixed. However, the fixing means of the test body 1 is not limited to this. The holding hole is provided so as to be orthogonal to the axial direction of the moment arms 3 and 3. Therefore, the moment arms 3 and 3 are arranged so as to be orthogonal to the axis 12 of the test body 1.

  Since the moment arms 3 and 3 have a phase angle θ with each other, and the length L of the pair of moment arms 3 and 3 is the same, the specimen 1 is held in an inclined state with respect to the load axis 4. Is done. Further, since the moment arms 3 and 3 are orthogonal to the axis 12 of the test body 1, the moment arms 3 and 3 have the length L and the axis 12 of the test body 1 with respect to the load axis 4 of the chucks 2 and 2. Eccentric.

  In the present embodiment, the pair of moment arms 3 and 3 are combined with the same shape to reduce the cost, but may be combined with different shapes.

  Next, the bending torsion composite load test method of the present invention will be described. This bending torsion composite load test method is such that the tip of a pair of moment arms 3 and 3 arranged with a phase angle θ between the specimen 1 and a pair of chucks 2 and 2 of a uniaxial load tester. The both ends of the test body 1 are held, the base ends of the pair of moment arms 3 and 3 are attached to the pair of chucks 2 and 2, and the bending moment is applied to the test body 1 by changing the distance between the pair of chucks 2 and 2. M and torsional moment T are applied simultaneously.

  When the moment arms 3 and 3 are attached to the chucks 2 and 2, respectively, and the specimen 1 is attached to the moment arms 3 and 3, and the tensile load is applied by operating the single-axis load tester, the specimen 1 is bent. Moment M and torsional moment T can be applied simultaneously. Therefore, a bending torsion test can be easily performed on the test body 1. In addition, since there is no need to change the chucks 2 and 2 themselves, a general-purpose machine can be used as it is as a single-axis load tester, and the cost required for the test can be reduced compared with the case of using a dedicated machine. Can do.

  The bending moment M applied to the test body 1 is obtained by Equation 1, and the torsion moment T is obtained by Equation 2.

  Here, L is the length of the moment arm 3, H is half the length of the test body 1, θ is the phase angle θ of the moment arm 3, and P is the tensile load (see FIG. 6).

  Further, the torsional bending moment ratio T / M is obtained by Equation 3.

  As is clear from Equation 1, the length L of the pair of moment arms 3 and 3 can be changed to adjust the magnitude of the bending moment M applied to the specimen 1. Further, as is apparent from Equation 2, the magnitude of the torsional moment T applied to the specimen 1 can be adjusted by changing the phase angle θ of the pair of moment arms 3 and 3. For these reasons, the magnitude of the bending moment M and the magnitude of the torsional moment T applied to the specimen 1 can be easily changed, and it is easy to repeat the test while changing these. It is also easy to change the torsional bending moment ratio T / M.

  As means for changing the length L of the moment arm 3, for example, a plurality of types of moment arms 3 having different lengths L are prepared, and the length L is changed by exchanging the moment arm 3. Alternatively, the length L may be changed by making the moment arm 3 extendable and contractable, or other means may be used.

  Further, as means for changing the phase angle θ of the moment arm 3, for example, a plurality of types of moment arms 3 having different phase angles θ are prepared, and the phase angle θ is changed by exchanging the moment arm 3. Alternatively, the phase angle θ may be changed by making the phase angle θ of the moment arm 3 variable, or other means may be used.

  The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the scope of the present invention.

  For example, in the above description, the axes of the moment arms 3 and 3 are orthogonal to the axis 12 of the test body 1, but it is not always necessary to orthogonally. In other words, although the moment arms 3 and 3 are perpendicular to the test body 1, they may be attached obliquely. Also in this case, the bending moment M and the torsional moment T can be applied.

1 Specimen 2 Chuck 3 Moment arm L Moment arm length M Bending moment T Torsional moment θ Phase angle of moment arm

Claims (4)

  The test body is decentered with respect to the pair of chucks of the uniaxial load tester, and both ends of the test body are held at the tips of a pair of moment arms arranged at a phase angle with each other. A bending torsion combined load test method, wherein a base end is attached to the pair of chucks, and a bending moment and a torsion moment are simultaneously applied to the test body by changing an interval between the pair of chucks.   2. The bending torsion composite load test method according to claim 1, wherein the bending moment applied to the specimen is adjusted by changing the length of the pair of moment arms.   2. The bending torsion composite load test method according to claim 1, wherein the magnitude of the torsional moment applied to the specimen is adjusted by changing the phase angle of the pair of moment arms.   A pair of moment arms for attaching both ends of the test body to a pair of chucks of a uniaxial load tester, the pair of moment arms being arranged with the test body eccentric with respect to the pair of chucks and at a phase angle with each other A bending torsion composite load test jig characterized by