JP5489975B2 - Impact test apparatus and impact test method - Google Patents

Description

  The present invention relates to an impact test apparatus and an impact test method for applying an impact to a specimen of a large structure.

  In general, the first unit of large structures such as flying objects and transportation equipment is subjected to an impact environment test to confirm whether it can withstand the impact of the specified severity before shipping or establishing the manufacturing process. . As this type of impact test apparatus, a system in which an impact pulse having a predetermined weight is applied to a specimen by causing a colliding member to collide with a large structure as a specimen is widely used. As a method for accelerating the collision member, a free fall method, a pendulum method, a high-pressure gas injection method, or the like is used. The magnitude of the shock pulse obtained by these methods is mainly determined by the collision speed of the collision member. .

  In the case of a free fall type or pendulum type impact test apparatus, a test piece is installed on a heavy object that is made sturdy, and the collision member is dropped from a high position. In the case of the high pressure gas injection method, the collision member is injected by increasing the gas pressure. Therefore, in the case of the free-fall method, the pendulum method, and the high-pressure gas injection method, there is a problem that the test apparatus is enlarged and complicated, and the test place is limited.

  As a method for solving such problems in the case of the free fall method, pendulum method and high pressure gas injection method, Patent Document 1 and Patent Document 2 include a table on which a specimen is mounted, a spring from the lower side of the table, and a spring. It is disclosed that a collision member is caused to collide with a specimen using a cylinder.

FIG. 5 shows a schematic configuration diagram of an impact test apparatus using a spring and a cylinder.
As shown in FIG. 5, the impact test apparatus 101 using a spring and a cylinder includes a table 114 on which a specimen 117 is mounted and a collision member 115 provided below the table 114. A structure in which the spring 116 connected downward is compressed by the cylinder 109, and the elastic energy accumulated in the compressed spring 116 is released at a stroke, whereby the collision member 115 is accelerated and moved upward to collide with the table 114. Thus, the impact test apparatus 101 is smaller than the impact test apparatus of the free fall system, the pendulum system, and the high pressure gas injection system.

FIG. 6 shows an impact pulse generated by the impact test apparatus 101 using the elastic energy of the spring 116 as described above.
In FIG. 6, the vertical axis indicates the magnitude of the shock pulse of the specimen 117, and the horizontal axis indicates the pulse width (application time). When the elastic energy of the spring 116 is used as in the impact test apparatus 101, the collision pulse magnitude (pulse) is increased by increasing the collision speed of the collision member 115 that collides with the table 114 on which the specimen 117 is fixed. It is possible to easily adjust the height.

JP 2000-249620 A JP 2007-24507 A

However, in the case of the impact test apparatus 101 using the elastic energy of the spring 116, it is difficult to adjust the pulse width to meet the standards of the impact environment test.
Further, the invention described in FIG. 5 and Patent Document 1 in which the collision member 115 is caused to collide with the table 114 using the spring 116 and the cylinder 109 from below the table 114 on which the specimen 117 is mounted is shown in FIG. An adjustment member 110 is provided on the upper surface side of 115 (the surface that collides with the table 114), and the pulse width is adjusted by adjusting the hardness of the adjustment member 110. Therefore, the adjustment of the pulse width is performed by trial and error based on an empirical rule, and there is a problem that it takes time for the entire impact environment test.

  The present invention has been made in view of the above-described circumstances, and the impact using the elastic energy of a spring capable of efficiently performing an impact environment test by shortening the time for adjusting the impact pulse width. It is to provide a test apparatus and an impact test method.

In order to solve the above problems, the present invention employs the following means.
An impact test apparatus according to the present invention includes a mounting base on which a specimen is fixed, a mounting bolt that is fixed at a predetermined height, and a breaking bolt that breaks when a force of a predetermined level or more acts. A cylinder that lifts the mounting table upward, a spring that is provided on the mounting table and applies a downward force to the mounting table by being compressed by the cylinder, and is provided below the mounting table. And a collision member that collides with the mounting base by a downward force applied to the spring, wherein the elastic coefficient of the spring is changeable.

  In the present invention, a break bolt that is provided on a mounting base to which the specimen is fixed and breaks when a force of a predetermined level or more acts, a cylinder that pulls the mounting base upward via the breaking bolt, and a cylinder that is compressed by the cylinder An impact test apparatus is provided that includes a spring and a collision member that collides with the specimen and the mounting base when the fracture bolt breaks, so that the elastic coefficient of the spring can be changed. Thus, by changing the elastic coefficient of the spring, it is possible to adjust the impact pulse width added to the specimen. In the impact test apparatus, the elastic energy accumulated in the spring compressed by the cylinder is released when the fracture bolt breaks, and the specimen and the mounting base rapidly move downward and collide with the collision member. As described above, when the mounting table rapidly accelerated downward collides with the collision member, an impact pulse is applied to the specimen. Therefore, the shock pulse width added to the specimen can be changed by changing the elastic coefficient of the spring. Therefore, the impact pulse width can be adjusted by a simple operation while downsizing the impact test apparatus.

  In addition, since the shock pulse width can be adjusted only by changing the elastic coefficient of the spring, the time required for the collision environment test can be shortened and the test can be performed efficiently.

  According to the impact test apparatus according to the present invention, the collision member is an absorption member that absorbs a downward force added by the collision of the mounting table, and the spring has a natural length, It is provided in the position contact | abutted with a mounting base.

  An absorbing member capable of absorbing a downward force applied to the collision member when the mounting table including the specimen collides is used as the collision member. Further, the collision member is provided so that the upper surface of the collision member is located at a neutral position of the free vibration of the mounting base connected to the spring. Thereby, the amplitude after the first shock pulse can be absorbed by the collision member. Therefore, it is possible to mainly acquire only the first shock pulse.

  According to the impact test apparatus of the present invention, the force with which the collision member collides with the mounting base can be adjusted by changing the total length of the breaking bolt.

  It was decided that the total length of the breaking bolt could be changed. Thereby, the compression amount of a spring can be changed. Therefore, it is possible to easily adjust the force with which the collision member collides with the mounting table.

  According to the impact test method of the present invention, the mounting table to which the specimen is fixed is fixed at a predetermined height, and the mounting table is inserted into the cylinder via the breaking bolt that is broken when a force of a predetermined level or more is applied. An impact test that pulls upward and applies a downward force to the mounting base by compressing a spring provided on the mounting base and causes the mounting base to collide with a collision member provided below the mounting base. In the impact test method for an apparatus, the elastic coefficient of the spring is changed.

According to the impact test apparatus of the present invention described above, a break bolt that is provided on a mounting base to which a specimen is fixed and breaks when a force of a predetermined level or more is applied, and the mounting base is pulled upward via the breaking bolt. A cylinder, a spring compressed by the cylinder, and a collision member that collides with the specimen and the mounting base when the fracture bolt breaks are provided, and the collision member is neutral vibration free of the mounting base to which the spring is connected. The upper surface of the collision member is provided at the position . Shock test apparatus is released elastic energy stored in the spring which has been compressed by the cylinder by the broken bolt is broken, specimen and mounting base collides with the collision member with rapid acceleration moves downward. As described above, when the mounting table rapidly accelerated downward collides with the collision member, an impact pulse is applied to the specimen. Therefore, by providing the collision member so that the upper surface of the collision member is positioned at the neutral position of the free vibration of the mounting base to which the spring is connected , the amplitude after the first shock pulse can be absorbed by the collision member. . Therefore, only the first shock pulse can be mainly acquired .

1 is a schematic configuration diagram of an impact test apparatus according to a first embodiment of the present invention. It is a graph at the time of changing an impact pulse width using the impact test apparatus shown in FIG. It is a graph which shows the relationship between the acceleration in the case of showing with the continuous line of FIG. It is a graph which shows the impact waveform in the case where there is a buffer material in the impact test apparatus shown in FIG. 1, and when there is no buffer material. It is a schematic block diagram of the conventional impact test apparatus. It is a graph which shows the relationship between the magnitude | size of an impact pulse by the impact test apparatus shown in FIG. 5, and an impact pulse width.

[First Embodiment]
Hereinafter, an impact test apparatus according to the present invention will be described with reference to FIGS.
FIG. 1 shows a schematic configuration diagram of an impact test apparatus according to the present embodiment.
In the illustrated impact test apparatus 1, the first unit of a large structure such as a flying object or a transportation device is used as a test piece 17, and a specified impact force is applied to the test piece 17, whereby the test piece 17 is strictly regulated. It is an apparatus for carrying out an impact environment test for confirming whether or not it can withstand the strength (impact force).

  The impact test apparatus 1 of the present embodiment is provided with a specimen 17 and collides a specimen-equipped table (mounting table) 14 having a predetermined weight with a buffer material (collision member) 15. This is a method of applying a shock pulse to the specimen 17 and performing the acceleration method of the specimen-equipped table 14 by releasing the elastic energy accumulated in the spring 16 at once.

  The impact test apparatus 1 includes a specimen-attached table 14 to which a specimen 17 is fixed, a specimen bolt-attached table 14 that is fixed at a predetermined height, and a fracture bolt 13 that breaks when a predetermined force or more is applied. The jack (cylinder) 9 that pulls the specimen-equipped table 14 upward through the break bolt 13 and the specimen-equipped table 14 are compressed by the jack 9 and are directed downward to the specimen-equipped table 14. A spring 16 for applying a force, and a buffer material 15 provided below the table 14 with a specimen and colliding with the table 14 with the specimen by a downward force applied to the spring 16 are mainly provided. .

The impact test apparatus 1 configured as described above has a surface plate 2 installed on the floor, and a plurality of columns 3 (for example, four, only two are shown in FIG. 1) are erected from the surface plate 2. ing. In the vicinity of the upper end of the column 3, a cross beam 4 supported by the four columns 3 so as to be parallel to the surface plate 2 is provided.
The horizontal beam 4 has a substantially rectangular parallelepiped shape. The lower surface of the horizontal beam 4 is a flat surface and is provided in parallel to the surface plate 2. A ceiling plate 5 is fixed to the lower surface of the horizontal beam 4.

  The ceiling plate 5 provided on the lower surface of the cross beam 4 has a substantially rectangular flat plate shape, and the lower surface side is a flat surface. The ceiling plate 5 is provided with spring adjustment seats 6 and spring adjustment bolts 7 extending downward from the four corners thereof. The spring adjustment seat 6 is provided on the outer periphery of the spring adjustment bolt 7. A screw thread is provided on the inner peripheral side of the spring adjustment seat 6 and can be screwed to the outer peripheral side of the spring adjustment bolt 7.

  A jack stand 8 is provided at a substantially central portion on the lower surface side of the ceiling plate 5. The jack mount 8 is provided with a jack 9 that reciprocates in the vertical direction on the inner peripheral side thereof. A flange 10 is provided at the lower ends of the jack mount 8 and the jack 9.

  The flange 10 provided at the lower ends of the jack mount 8 and the jack 9 has a stopper 11 connected to the lower surface thereof via a connection bolt 10a. The stopper 11 has a substantially rectangular parallelepiped shape, and a jack adapter 12 described later is accommodated inside the stopper 11. As shown in FIG. 1, the substantially rectangular parallelepiped stopper 11 has a substantially trapezoidal shape, and tapers downward from the lower surface side of the flange 10.

  The jack adder 12 described above is provided at a substantially central portion on the lower surface side of the flange 10 surrounded by the stopper 11. The jack adder 12 is connected to the jack 9 via the flange 10, and can move in the vertical direction in accordance with the movement of the jack 9. The jack adapter 12 has a breaking bolt (rupture bolt) 13 for fixing the specimen-equipped table 14 to a predetermined height at a substantially central portion at the lower end thereof.

  A spring 16 is connected to the lower end of the spring adjustment bolt 7 extending downward from the four corners of the ceiling plate 5. For example, four springs 16 are provided, and the lower ends of the springs 16 are connected to the four corners of the table 14 with the specimen and suspend the table 14 with the specimen. The springs 16 are desirably connected between the four corners of the ceiling plate 5 and the four corners of the table 14 with the specimen via the spring adjustment bolts 7, but this is not a limitation depending on the number of springs 16 to be installed.

  The specimen-attached table 14 that is suspended by the spring 16 has a substantially cubic shape. The table 14 with a specimen is composed of an upper table 14a, a lower table 14b, and two leg portions 14c connecting the upper table 14a and the lower table 14b. The two leg portions 14c connect the upper table 14a and the lower table 14b so as to be substantially parallel to the column 3.

  The upper table 14a is a flat plate having a predetermined thickness, and both the upper surface side and the lower surface side are flat. On the upper surface side of the upper table 14a, springs 16 are connected to the four corners, and the opposite end of the breaking bolt 13 connected to the jack adapter 12 is fixed to the substantially central portion.

  The lower table 14b has a flat upper surface and a substantially central portion on the lower surface bent in a convex shape downward. A specimen 17 for performing an impact environment test is fixed to the upper surface side of the lower table 14b. A buffer material (absorbing member) 15 is provided below the lower surface side of the lower table 14b, and is in contact with a convex portion at a substantially central portion on the lower surface side.

  The cushioning material 15 is a convex portion on the lower surface side of the lower table 14b of the lower table 14b of the table 14 with the specimen that is suspended by the spring 16 at a position where it becomes a neutral position when the table 14 with specimen freely vibrates. A vertex is provided. The cushioning material 15 is an absorbing member that can absorb the downward force applied to the cushioning material 15 when the table with the specimen 14 provided with the specimen 17 collides. For example, hard urethane or the like Is used.

  The breaking bolt 13 is provided with a notch (notch) (not shown) at a substantially central position in the axial direction. This notch can be broken by pulling the breaking bolt 13 by the jack 9 via the jack adapter 12 and applying a tensile force (force) of a predetermined value or more to the breaking bolt 13.

  The table 14 with the specimen suspended from the cross beam 4 via the spring adjustment seat 6 by the four springs 16 is provided by a guide 18 provided so as to protrude from the column 3 toward the table 14 with the specimen. The movement in the horizontal direction is restricted. Therefore, the table 14 with the specimen moves only in the vertical direction along the guide 18.

Next, an impact environment test method (impact test method) using the impact test apparatus according to the present embodiment will be described with reference to FIGS.
The specimen 17 is fixed to the upper surface side of the lower table 14b of the table with specimen 14 with a bolt (not shown) or the like. The four springs 16 are attached to the four corners on the upper surface side of the upper table 14a of the table with the specimen 14 to which the specimen 17 is fixed.

  The springs 16 attached to the four corners of the upper table 14 a are attached to the spring adjustment bolt 7. By screwing the spring adjustment bolt 7 to the spring adjustment seat 6 provided on the lower surface side of the ceiling plate 5, the table 14 with the specimen is suspended and supported by the ceiling plate 5. The convex part of the substantially central part on the lower surface side of the lower table 14b of the table 14 with the specimen hanging down in this state is in contact with the cushioning material 15 provided below the table 14 with the specimen. . This position is the neutral position.

  Further, the jack 9 is extended, and the breaking bolt 13 is attached between the lower end of the jack 9 and the upper surface side of the upper table 14a of the table 14 with the specimen. The breaking bolt 13 attached in this way has no tensile force acting at this time.

  Next, the jack 9 is operated so as to be pulled upward in FIG. As a result, the spring 16 is compressed, and the specimen-equipped table 14 moves upward. Further, by operating the jack 9 to be pulled in, the upper surface side of the upper table 14 a of the table 14 with the specimen and the lower end of the stopper 11 provided at the lower end of the jack mount 8 come into contact with each other. At this time, the compression of the spring 16 is finished, and the compression force is kept constant thereafter.

  Even if the pull-in of the jack 9 is regulated by the stopper 11 and the jack mount 8, the operation is performed so that the jack 9 is continuously pulled in. Then, a tensile force acts on the breaking bolt 13 gradually. Thus, when the tensile force acting on the breaking bolt 13 reaches a predetermined value, the breaking bolt 13 is instantaneously broken from the notch.

  When the breaking bolt 13 is broken, the elastic energy accumulated in the compressed spring 16 is released at once. By releasing the elastic energy accumulated in the spring 16, the table with specimen 14 moves downward. At this time, the specimen-equipped table 14 is accelerated and moved by the spring 16, and the convex portion on the lower surface side of the lower table 14 b of the specimen-equipped table 14 collides with the cushioning material 15 in the neutral position. As a result, a shock pulse is applied to the specimen 17 fixed to the specimen-equipped table 14.

The impact pulse width given to the specimen 17 by such an impact test apparatus 1 can be obtained from the weight of the spring 16 and the table 14 with specimen. That is, it is generally known that the natural frequency f obtained from the spring constant (elastic coefficient) K of the spring 16 and the weight M of the table with specimen 14 is expressed by the following equation.
f = ^1/2 × π × (K / M) ^1/2 (1)
The frequency F that is the reciprocal of the natural frequency f obtained by the equation (1) is the shock pulse width given to the specimen 17.

  Here, since the weight M of the table 14 with the specimen is constant, the shock pulse width is a function of the spring constant K. Therefore, the shock pulse width can be easily adjusted by changing the spring constant K.

Next, a method for adjusting the shock pulse width will be described.
When adjusting the shock pulse width, the spring constant K is changed. That is, the spring 16 having a different spring constant K is exchanged or the number of the springs 16 is changed. Thus, the impact pulse width (application time) of the specimen 17 is adjusted by using the impact test apparatus 1 in which the spring constant K can be changed.

FIG. 2 shows a graph when the impact pulse width is changed using the impact test apparatus 1 of the present invention.
In FIG. 2, the vertical axis represents the magnitude of the shock pulse, and the horizontal axis represents the shock pulse width.
By changing the spring constant K as described above, the shock pulse width of the specimen 17 (width indicated by the arrow parallel to the horizontal axis in FIG. 2) as shown by the solid line, the alternate long and short dash line in FIG. Can be changed.

FIG. 3 shows a graph showing the relationship between the acceleration and frequency of the spring constant K indicated by the solid line in FIG.
In FIG. 3, the vertical axis represents acceleration and the horizontal axis represents frequency.
The impact test apparatus 1 of the present embodiment has a cushioning material 15. Therefore, as shown in FIG. 3, the buffer material 15 can absorb the amplitude after the first shock pulse.

Here, for comparison, a case where the buffer material 15 is provided and a case where the buffer material 15 is not provided will be described with reference to FIG.
FIG. 4 shows a graph showing impact waveforms when the impact test apparatus 1 of the present embodiment has the cushioning material 15 and when there is no cushioning material 15.
In FIG. 4, the vertical axis represents the amplitude of vibration, and the horizontal axis represents time. A solid line indicates a case where the cushioning material 15 is not provided, and a broken line indicates a case where the cushioning material 15 is inserted in a neutral position.

  When the buffer material 15 is not provided, the amplitude of vibration of the table with specimen 14 on which the specimen 17 is mounted becomes free vibration, and the amplitude attenuates with time as shown by the solid line in FIG. Become. On the other hand, when the shock absorber 15 is provided, other than the first amplitude is absorbed by the shock absorber 15 at the neutral position of the impact test apparatus 1. Therefore, as shown by the broken line in FIG. 4, only the first amplitude has the same shape as the case where there is no buffer material 15, but the amplitude other than the first amplitude, that is, the amplitude after the first amplitude is almost zero. As described above, by providing the cushioning material 15 at the neutral position, it is possible to measure only the first impact pulse during the impact environment test.

As described above, according to the impact test apparatus 1 and the impact test method according to the present embodiment, the following operational effects can be obtained.
A breaking bolt 13 that is provided on a specimen-equipped table (mounting base) 14 to which the specimen 17 is fixed and breaks when a tensile force (force) of a predetermined value or more acts, and the specimen through the breaking bolt 13 A jack (cylinder) 9 that pulls the attached table 14 upward, a spring 16 that is compressed by the jack 9, and a shock absorber (impact member) that collides with the specimen 17 and the specimen-equipped table 14 when the breaking bolt 13 breaks. 15, and the impact test apparatus 1 that can change the spring constant (elastic coefficient) K of the spring 16 is used. Thus, by changing the spring constant K of the spring 16, the width of the shock pulse applied to the specimen 17 can be adjusted. In the impact test apparatus 1, the elastic energy accumulated in the spring 16 compressed by the jack 9 is released when the breaking bolt 13 breaks, and the specimen 17 and the specimen-equipped table 14 rapidly move downward. And collide with the buffer material 15. As described above, when the table 14 with the specimen rapidly accelerating downward collides with the buffer material 15, an impact pulse is applied to the specimen 17. Therefore, by changing the spring constant K of the spring 16, the shock pulse width added to the specimen 17 can be changed. Therefore, the impact pulse width can be adjusted by a simple operation while reducing the size of the impact test apparatus 1.

  Further, since the impact pulse width can be adjusted only by changing the spring constant K of the spring 16, it is possible to reduce the time for performing the collision environment test and to perform the test efficiently.

  Hard urethane capable of absorbing the downward force added to the cushioning material 15 by collision of the specimen-equipped table 14 provided with the specimen 17 is used for the cushioning material (absorbing member) 15. . Further, the cushioning material 15 is provided so that the upper surface of the cushioning material 15 is positioned at the neutral position of free vibration of the table with specimen 14 to which the spring 16 is connected. As a result, the amplitude after the first shock pulse that has impacted the buffer material 15 can be absorbed by the buffer material 15. Therefore, it is possible to acquire only the first shock pulse.

[Second Embodiment]
The impact test apparatus of the present embodiment is different from the first embodiment in that the entire length of the broken bolt is changed, and the others are the same. Therefore, about the same structure and test method, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  The force with which the table with the specimen (mounting table) on which the specimen is fixed collides with the buffer material (impact member, absorbing member) varies depending on the amount of compression of the spring. Therefore, it was decided to change the total length of the break bolts installed between the jack adapter and the upper table of the table with the specimen.

  That is, the distance between the lower end of the jack adapter and the upper table of the table with the specimen can be changed by changing the total length of the breaking bolt. Since the total length of the breaking bolt changes, the distance that the jack (cylinder) pulls the table with the specimen upward is changed. Therefore, the compression amount of the spring compressed by the jack can be changed. Therefore, it is possible to control the force of causing the table with the specimen to collide with the buffer material independently of the adjustment of the shock pulse width.

As described above, according to the impact test apparatus and impact test method according to the present embodiment, the following operational effects can be obtained.
The total length of the broken bolt was changed. Thereby, the compression amount of a spring can be changed. Therefore, it is possible to easily adjust the force that causes the table with the specimen to collide with the buffer material.

  In addition, this invention is not limited to embodiment mentioned above, In the range which does not deviate from the summary, it can change suitably.

1 Impact test device 4 Table with specimen (mounting base)
9 Jack (cylinder)
13 Breaking bolt 15 Buffer material (impact member, absorbing member)
16 Spring 17 Specimen

Claims (5)

A mounting base on which the specimen is fixed;
The mounting base is fixed at a predetermined height, and a breaking bolt that breaks when a force exceeding a predetermined level is applied,
A cylinder that pulls the mounting table upward via the breaking bolt;
A spring that is provided on the mounting table and applies a downward force to the mounting table by being compressed by the cylinder;
A collision member that is provided below the mounting table and collides with the mounting table by a downward force applied to the spring;
The collision member is an absorbing member that absorbs a downward force added by the collision of the mounting table, and is provided at a position where the spring comes into contact with the mounting table when the spring has a natural length. Characteristic impact test equipment. The impact test apparatus according to claim 1, wherein an elastic coefficient of the spring is changeable .   The impact test apparatus according to claim 1 or 2, wherein a force with which the collision member collides with the mounting base can be adjusted by changing a total length of the breaking bolt. The mounting base on which the specimen is fixed is fixed at a predetermined height, and the mounting base is pulled up by a cylinder through a breaking bolt that is broken when a force of a predetermined level or more is applied, and provided on the mounting base. In the impact test method in which a downward force is applied to the mounting base due to compression of a spring, and the mounting base collides with a collision member provided below the mounting base, the collision member includes the mounting base. An impact test method , comprising: an absorbing member that absorbs a downward force applied by the collision of the spring, wherein the spring is provided at a position in contact with the mounting base when the spring has a natural length . The impact test method according to claim 4, wherein an elastic coefficient of the spring is changeable.

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