JP3243524B2 - Displacement measuring device and displacement measuring device for drop impact tester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a displacement measuring device and a displacement measuring device for a drop-type impact test device.

[0002]

2. Description of the Related Art In a drop-type impact test apparatus, an impact is applied by a weight that falls on a specimen on a floor, or the impact is attached to the weight, and falls along with the weight to collide with the floor. The main purpose is to calculate the impact energy according to the amount of deformation of the shocked specimen.
It starts contacting the specimen on the floor, and the impact load of the weight causes the specimen to absorb the impact energy of the weight and deform, and finally, until the weight stops falling,
It is necessary to measure the amount of drop of the weight every predetermined time, that is, the amount of displacement, and the acceleration of the weight (or the load applied to the specimen).

[0003] Hereinafter, a drop-type impact test device and a conventional displacement measuring device used in the drop-type impact test device will be described with reference to FIG. First, a drop-type impact test device will be described. FIG. 8A shows a state in which the weight is fixed at a predetermined height position, and FIG. 8B shows that after the load metal fitting of the weight starts to contact the test piece, the weight drops freely by 80 mm to remove the test piece. This shows a state in which the specimen is deformed by impact and the falling of the weight is stopped. In FIGS. 8A and 8B, W is a weight, which is located at the center of each of the walls Ka and Kb of the frame FL via the linear motion bearings Ba and Bb on both sides thereof.
A pair of rails Ra, R attached to extend vertically
b so that it can move up and down. A load fitting LK is attached to the lower surface of the weight W, and the shape of the load fitting LK on the side that collides with the test piece TP is selected in accordance with the shape and material of the test piece TP. Thus, various methods of applying an impact load to the specimen TP can be selected.

[0004] Although not shown, the weight W is suspended from a suspended portion which is guided up and down by a pair of rails Ra and Rb via the same linear bearing as the weight W, and the suspended portion is The wire rope is attached to one end of the wire rope, and the wire rope is wound by a winder, and the winder is rotated by a motor, whereby the weight W can be moved up and down. Then, when the suspension of the weight W by the suspension portion is released, the weight W falls freely.
Further, as shown in FIG. 8B, a modified specimen TP
The weight W on the upper side is suspended from the suspension portion, and the wire rope is wound by a motor, so that the weight W can be lifted to the original stop position.

Next, a conventional displacement measuring device in a drop-type impact test device will be described. An optical laser displacement meter DM for measuring a distance between the lower surface of the weight W and the lower surface of the weight W at predetermined intervals is attached to a portion of the frame FL near the wall Kb on the floor surface FL. Regarding the principle of this optical laser displacement meter DM,
A specific example of the embodiment of the present invention will be described with reference to FIG. This optical laser displacement meter DM can measure a maximum displacement (longest distance) of 200 mm, has a measurement resolution of 0.5 mm, and a response speed of 0.9 kHz. And actually, the position of the lower surface of the weight W when the lower surface of the load metal fitting LK of the weight W contacts the top surface of the specimen TP;
As shown in FIG. 8B, the lower surface of the weight of the displacement meter DM is between the displacement (distance) d and the position of the lower surface of the weight W when the weight W falls and collides with the specimen TP and stops. Is measured every (1/900) sec. In this case, the weight W is not deformed by the collision with the specimen TP.

Next, a circuit of the displacement measuring device in FIG. 8 will be described with reference to FIG. The distance (displacement amount) at a predetermined time interval by the displacement meter DM (2) is supplied to a displacement / signal voltage converter (controller) 4 and converted into a signal voltage.
The signal voltage is supplied to an A / D converter in the memory 6 to be converted into a digital signal voltage, and then stored in the memory 6. Since the maximum displacement of 200 mm corresponds to the signal voltage of 10 V, the computer 7 converts the digital signal voltage stored in the memory 6 into a displacement of 20 (m) per unit voltage.
m / V), and use this as a proportional coefficient. Then, when a certain amount of displacement is detected by the displacement meter 2, the signal voltage from the displacement / signal voltage converter 4 is digitized by an A / D converter in the memory 6 and stored in the memory 6. Let it. In the computer 7, the original displacement can be obtained by multiplying the digital signal voltage read from the memory 6 by a proportional coefficient. In addition, the measurement output of the other measuring devices associated with the impact load of the weight W on the specimen is also supplied to the memory 6 and digitized and stored, and based on the measurement output of the other measuring devices, The point at which W freely falls and starts contacting the specimen is detected, and these will be described in the description of the displacement measuring device according to the embodiment of the present invention in FIG. The description here is omitted.

Next, the measuring operation of the conventional displacement measuring device shown in FIG. 9 will be described. The weight W is measured by the optical laser displacement meter 2.
Is measured at predetermined time intervals, and is measured by a displacement / signal-to-voltage converter (controller) 4.
Is converted into a signal voltage, and the signal voltage is
Specimen TP with weight W under test conditions by D converter
A maximum of 4 words per channel as sampling data at the same time while performing A / D conversion at an arbitrary sampling interval (for example, 10 μsec, that is, 100 kHz expressed in clock frequency) in consideration of the impact load speed for , Stored in the memory 6. The following calculation is performed by the computer 7 and the calculation result is output to the display device 8 and the printer 9. That is, the digital signal voltage read from the memory 6 is multiplied by a digital value of a displacement amount per unit voltage of 20 (mm / V) to calculate displacement amount data, and adjacent ones of the respective displacement amount data are calculated. By calculating the difference, the falling distance of the weight W every predetermined time, that is, the displacement amount can be calculated.

Next, a step-like characteristic of the displacement amount with respect to the elapsed time (× 10 ⁻³ sec) by the conventional displacement measuring device in FIG. 6 will be described. The data measured by the conventional displacement measuring device shown in FIG. 9 shows that the response speed of the optical laser displacement meter is 0 when the initial value of the impact velocity for applying a load to the specimen by the free fall of the weight is 10 m / sec. .9kHz
Since z (s ⁻¹ ), 10 m ÷ 900 s ⁻¹ = 0.01
11 m / sec = 11.1 mm / sec, which is 11.1 m
The displacement at one point is detected at intervals of m / sec.
The displacement meter continues to output the previously detected value until a new detection is performed on the next sample. The displacement data stored in the memory 6 is 100 kHz / 0.1 .times. When the sampling time by the A / D converter in the memory 6 is 10 .mu.sec (100 kHz (s.sup.- ¹ ) when expressed by a clock frequency).
9 kHz = 111.1, and after the displacement meter detects a point in time, a continuous output signal until the next point is detected is stored in the memory 6 as approximately 111 identical data.

As can be seen from FIG. 6, in the detection within the response speed range of the displacement meter (0.9 kHz or less), the resolution is not more than 0.1.
Even if it is 5 mm, if the load speed condition is 10 m / sec in this test, the detectable measurement range is 11.1 m
m, the actual measurement accuracy is 11.1 mm, which is limited by the response speed. In the test, the displacement data actually measured is a value of a decreasing tendency due to the sequential effect of the weight as a large change, but it changes while oscillating irregularly in detail, and more than 100 points At intervals, it is impossible to interpolate and use the middle of the measurement results. In addition, the measurement itself with a resolution of about 11 mm for the measurement amount of the maximum measurement amount of 200 mm,
Not practical.

[0010]

SUMMARY OF THE INVENTION In view of the above, the present invention relates to a displacement measuring apparatus having a moving body and an optical laser displacement meter for measuring a dynamic displacement of the moving body. An object of the present invention is to propose a sensor which has a wide range in which the amount of measurement can be measured and which has a high measurement resolution of the moving distance (displacement amount) of the moving body at predetermined time intervals.

[0011] Further, the present invention provides a weight capable of free fall,
After the specimen (or the specimen attached to the weight) located on the floor surface and the weight falls and starts contacting the specimen (or the specimen attached to the weight An optical laser displacement meter that measures the dynamic displacement of the weight until the specimen is completely deformed by the impact of the weight after the contact is started).
An object of the present invention is to propose a device that has a wide measurable range of the moving amount of the weight and has a high resolution for measuring the falling distance (displacement amount) of the weight every predetermined time.

[0012]

According to a first aspect of the present invention, there is provided a displacement measuring apparatus comprising a moving body and an inclined surface attached to the moving body and having a predetermined inclination with respect to the moving direction of the moving body. An optical laser displacement meter that measures the distance between the inclined jig and the inclined surface accompanying the movement of the inclined jig at predetermined time intervals, and an optical laser displacement meter that moves from one point of the moving body to another point. The difference between each adjacent distance between the slope and the slope measured at a predetermined time, which is measured by the laser displacement meter, is calculated, and each difference is multiplied by a proportional coefficient corresponding to a predetermined slope of the slope to move. Calculating means for calculating the amount of displacement of the body every predetermined time.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first aspect of the present invention relates to a movable jig, an inclined jig provided on the movable body and having an inclined surface having a predetermined inclination with respect to a moving direction of the movable body, and an inclined jig thereof. An optical laser displacement meter that measures the distance between the inclined plane and the moving surface at predetermined intervals, and an optical laser displacement meter that measures the distance from one point of the moving body to another point. Calculate the difference between adjacent distances with the inclined surface at predetermined time intervals, multiply each difference by a proportional coefficient corresponding to the predetermined inclination of the inclined surface, and calculate the displacement amount of the moving body at predetermined time intervals. And a calculating means for calculating the displacement amount.

According to a second aspect of the present invention, there is provided a weight capable of free fall, a specimen located on a floor surface (or mounted on the weight), and a falling direction of the weight mounted on the weight. An inclined jig having an inclined surface having a predetermined inclination with respect to an optical laser displacement meter for measuring a distance between the inclined surface with the movement of the inclined jig every predetermined time, Along with the movement to the point, the difference between each adjacent distance between the slope and the slope measured at a predetermined time, which is measured by the optical laser displacement meter, is calculated. And a calculating means for calculating the amount of displacement of the weight every predetermined time by multiplying by a proportional coefficient according to the following formula.

According to a third aspect of the present invention, there is provided an inclined jig having a movable body, an inclined surface attached to the movable body and having a predetermined inclination with respect to the moving direction of the movable body, and a plane parallel to the moving direction of the movable body. And a first optical laser displacement meter that measures the distance between the inclined surface associated with the movement of the inclined jig at predetermined time intervals, and the distance between a plane associated with the movement of the inclined jig at predetermined time intervals. The distance between the second optical laser displacement meter to be measured and the plane at predetermined time intervals measured by the second optical laser displacement meter with the movement of the moving body from one point to another point. A difference between each distance and each distance between the inclined plane and the distance measured at the first optical laser displacement meter corresponding to each distance is calculated. The difference between adjacent objects is calculated, and each difference is calculated according to a predetermined inclination of the inclined surface. Was multiplied by proportional coefficient, a displacement measuring device with a calculating means for calculating a displacement amount of each predetermined time of the mobile.

According to a fourth aspect of the present invention, there is provided a weight capable of free fall, a specimen located on a floor surface (or mounted on the weight), and mounted on the weight, and a falling direction of the weight. A first optical system for measuring a distance between an inclined jig having an inclined surface having a predetermined inclination and a plane parallel to the moving direction of the weight, and an inclined surface accompanying the movement of the inclined jig at predetermined time intervals Type laser displacement meter, a second optical laser displacement meter that measures the distance between the plane accompanying the movement of the tilt jig every predetermined time,
Along with the movement of the weight from one point to another point, each distance between the plane and the plane every predetermined time, which is measured by the second optical laser displacement meter, corresponds to each of the distances. The difference between each of the distances from the inclined surface measured at a predetermined time, which is measured by the first optical laser displacement meter, is calculated, and the difference between adjacent ones of each of the differences is calculated. To the difference
A displacement means for calculating a displacement amount of the weight every predetermined time by multiplying by a proportional coefficient according to a predetermined inclination of the inclined surface.

[Specific Example of Embodiment of the Invention] A drop-type impact test apparatus will be described below with reference to FIG.
FIG. 5A shows a state in which the weight is fixed at a predetermined height position, and FIG. 5B shows a state in which the metal fitting for load attached to the lower surface of the weight starts contact with the specimen ( The initial speed of the weight W at this time is, for example, 10 m / se.
FIG. 5C shows a state in which the loading bracket of the weight falls freely by 80 mm after coming into contact with the specimen, impacts the specimen, and completes the deformation of the specimen. In FIGS. 5A, 5B, and 5C, W is a weight, which extends vertically through the linear motion bearings Ba and Bb on both sides thereof at the center of the walls Ka and Kb of the frame FL. It is mounted so that it can be moved up and down by being guided by a pair of mounted rails Ra and Rb. On the lower surface of the weight W, a load bracket LK is provided.
Is mounted, and the test piece TP of this load metal fitting LK is attached.
By variously selecting the shape of the side that collides with the specimen, it is possible to variously select how to apply an impact load to the specimen TP according to the shape, material, and the like of the specimen TP.

Although not shown in the drawings, the weight W is suspended from a suspended portion which is guided up and down by being guided by a pair of rails Ra and Rb via the same linear bearing as the weight W, and the suspended portion is The wire rope is attached to one end of the wire rope, and the wire rope is wound by a winder, and the winder is rotated by a motor, whereby the weight W can be moved up and down. Then, when the suspension of the weight W by the suspension portion is released, the weight W falls freely.
Further, as shown in FIG. 5C, a modified specimen TP described later is used.
The weight W on the upper side is suspended from the suspension portion, and the wire rope is wound by a motor, so that the weight W can be lifted to the original stop position.

The weight W is made of, for example, a material such as stainless steel or an aluminum alloy.
It has a rectangular flat plate shape of × 250 mm. By attaching an additional weight to the weight W, the overall weight can be increased.

TP is a specimen mounted on the floor surface FL in the frame FL. As the specimen TP, in addition to those having simple shapes such as plates and pipes, the components of the aircraft itself,
Alternatively, there is a complicated shape such as a model thereof, and the material is also a metal, a composite material, or the like.

Then, as shown in FIG. 5B, the weight W falls freely and the load metal fitting L attached to the lower surface of the weight W
After K starts contacting the specimen TP, as shown in FIG. 5C, the weight W collides with the specimen TP, and the specimen TP
The amount of displacement (displacement) of the weight W every predetermined time until the weight W stops falling after the deformation of the weight W is completed is measured by the optical laser displacement meter DM between the slope of the tilt jig SJ. (Horizontal distance) is measured at predetermined time intervals, and is calculated to calculate the distance.

The specimen is fixed directly to the lower surface of the weight W or through a mounting bracket, and the weight W and the specimen are allowed to freely fall so that the specimen collides with the floor surface. Alternatively, an impact load may be applied to the specimen. In this case, a load fitting similar to that shown in FIG. 5 is mounted on the floor surface, and various methods of applying an impact load applied to the specimen by the floor surface can be selected according to the shape of the load fitting.

The weight W has a minute play in a plane perpendicular to the vertical movement direction, and is at most 0.02 mm. When the influence of the backlash of the weight W on the distance measured by the displacement meters 2 and 3 between the inclined surface u and the vertical surface v of the inclined jig 1 was examined, the weight W When the movement is performed only in the direction (horizontal direction) (the y direction in FIG. 2), since the inclined surface u and the vertical surface v are flat, the measurement is performed in the y-axis direction (see FIG. 2) of the inclined surface u. It turned out to be unnecessary. When the weight W is rotated in the xy plane, the length of the weight W in the y-axis direction is about 900 mm, whereas the backlash is an angle correction, and the weight of the weight W is measured in the x-axis direction. The effect of the play is much smaller than the pure play in the x direction and is negligible. For this reason, it was found that it is sufficient to correct only the play in the x-axis direction of the v-plane for the play in the x-axis direction of the inclined surface u. Note that a direction orthogonal to the above-described xy axis is defined as z.

Next, with reference to FIG. 5 again, a description will be given of a displacement measuring device as a specific example of the embodiment of the present invention in the drop impact test device. An inclined jig SJ along the falling direction of the weight W is mounted near the linear motion bearing Bb on the front surface of the weight W, and the displacement of the inclined surface and the vertical plane of the inclined jig SJ is measured in the frame FL. Optical laser displacement meter DM
To the fixed part.

Next, the circuit of the displacement measuring device in FIG. 5 will be described with reference to FIG. The distance and the vertical plane (vertical plane) V between the inclined jig 1 (SJ) (downward in the direction perpendicular to the paper surface of FIG. 1) and the inclined plane U attached to the weight W
And the distance between each optical laser displacement meter DM (2,
Measure separately for each according to 3). The distances (displacement amounts) at predetermined time intervals, which are values measured by the displacement meters 2 and 3, are supplied to displacement / signal-voltage converters (controllers) 4 and 5 to be converted into signal voltages. In the memory 6
After supplying it to the / D converter and converting it to a digital signal voltage,
It is stored in the memory 6. The digital signal voltage stored in the memory 6 is converted by the computer 7 into a maximum displacement 200
Since the mm corresponds to the signal voltage of 10 V, the displacement 20 per unit voltage (mm / V) is calculated.

Also, the measurement output of the other measuring instruments accompanying the impact load of the weight W on the specimen is supplied to the memory 6, digitized and stored, and based on the measurement outputs of the other measuring instruments. The point at which the weight W falls freely and starts contacting the specimen is detected, which will be described later.

Next, the measuring operation of the displacement measuring device of the specific example of FIG. 1 will be described. The distances (displacement amounts) between the inclined surface U and the vertical surface V of the inclined jig 1 (SJ) are simultaneously and separately measured by the optical laser displacement meters 2 and 3 at the same predetermined time, and are measured. The signal voltage is converted into a signal voltage by the signal voltage converters (controllers) 4 and 5, and the signal voltage is converted by the A / D converter in the memory 6 into an impact load on the specimen TP by the weight W under the test conditions. At an arbitrary sampling interval considering the speed (for example, 10 μsec, that is, 100 kHz when expressed by a clock frequency), the A / D
While performing the conversion, up to four words per channel are stored in the memory 6 as sampling data at the same time.

The computer 7 multiplies the digital signal voltage read from the memory 6 for each predetermined time by a digital value of a displacement amount per unit voltage of 20 (mm / V) to obtain displacement amount data. By calculating the difference between the displacement amount data to be obtained and the difference between adjacent ones of the differences, and multiplying the difference by a proportional coefficient corresponding to the inclination direction of the inclined surface U with respect to the falling direction of the weight W, that is, the vertical direction. , Weight W
Can be obtained for every predetermined time, that is, the displacement amount. The displacement amount of the weight W every predetermined time is output to the display device 8 and the printer 9.

Next, the shape of the inclined jig 1 will be described with reference to FIG. This inclined jig has two blocks BLu, BL
It can be considered that v is integrated. One of the blocks BLu has an inclined surface (inclined plane) U whose displacement is measured by the displacement meter 2, and a horizontally elongated protrusion P having a rectangular parallelepiped shape is provided at a lower end of the inclined surface U. L
u indicates a displacement measurement trajectory by the displacement meter 2 and coincides with the center line of the inclined surface U. The other block BLv has a rectangular parallelepiped shape, and has a vertical plane (vertical plane) V on which the displacement is measured by the displacement meter 3. Lv indicates a displacement measurement trajectory by the displacement meter 3 and coincides with the center line of the vertical plane V. The inclined plane U is inclined with respect to the vertical plane V by a certain angle (this is θ).

The z-axis direction of the inclined jig SJ (1) (as shown in FIG. 2, equal to the direction of the center line of the vertical plane V and perpendicular to the top surface) coincides with the falling direction of the weight W. Then, the inclined jig SJ (2) is attached to the weight W as shown in FIG. 5 on the surface opposite to the portion where the inclined surface U and the vertical surface V are formed, that is, on the back surface.

As shown in FIG. 5B, when the weight W falls freely and starts to contact the specimen TP, as shown in FIG. 2, the displacement measurement trajectory Lv and the inclined surface on the vertical surface V of the inclined jig 1 are measured. The displacement measurement trajectory Lu on U and the height in the z direction are Zs
The difference between the displacement amounts measured by the displacement gauges 3 and 2 at the respective intersections Vs and Us with the straight line Zs (reference height) is -3 m.
m, then the weight W is lowered by 200 mm, and the displacement measurement trajectory Lv on the vertical plane V of the inclined jig 1 and the displacement measurement trajectory Lu on the inclined plane U, and a straight line Z whose height in the z direction is Ze
The inclined surface U is adjusted so that the difference between the displacement amounts measured by the displacement gauges 3 and 2 at the respective intersections Ve and Ue with e becomes +3 mm.
, The right side of the vertical plane V, and one side of the top surface of the block BLu (a plane perpendicular to the vertical surface V) (the top surface of the block BLv also belongs to the same plane as the top surface of the block BLu). Assuming that the side h of the triangle Δ orthogonal to is set to 6 mm, the difference between the displacement amounts measured by the displacement meters 3 and 2 −
It can be seen that the displacement amount difference of 6 mm (= L) from the measurement of 3.0 mm to the measurement of the displacement amount + 3 mm corresponds to the movement amount of the weight W of 200 mm.

The displacement at the intersections Vm and Um of the displacement measurement trajectory Lv on the vertical plane V and the displacement measurement trajectory Lu on the inclined plane U of the inclined jig 1 and the straight line Zm having the height Zm in the z direction. The difference between the displacement amounts measured by the total 3 and 2 is hm
, The moving amount of the weight W is obtained by the following equation (1). This calculation is performed by the computer 7.

[0033]

## EQU1 ## (Zm-Zs) = {hm- (play in vertical direction V in x direction)} / 6 × 200 (mm)

The protrusion P provided on the lower end side of the inclined surface U will be described. The protruding portion P is a rectangular parallelepiped having the same width as the inclined surface U, a height L ₀ (= 0.002 mm), and a depth h ₀ . The time when the height L ₀ of the protrusion P passes is shown in FIG.
S, the average speed between both edges of the protruding portion P is L ₀ /S=0.002 mm / S.

Next, the sectional shape of the block BLu of the inclined jig 1, that is, the sectional shape of the inclined surface u will be described with reference to FIG. However, in FIG. 3, hatching is omitted to make the drawing easier to see. FIG. 3A shows a cross section of the block BLu of the inclined jig shown in FIG. 2, and the cross section of the inclined surface U is a straight line. hm ′ indicates the thickness of the block BLu in the portion where the height in the z-axis direction of the inclined plane U and the vertical plane V is Zm. h ₂ indicates the thickness of the top surface of the block BLu. h
₁ indicates the thickness of the block BLu at the lower end of the inclined surface U. L indicates the height of the inclined surface U in the z-axis direction. Lm is
When the reference height Zs is set to 0, the height in the z-axis direction is Zm.
, Which corresponds to the amount of movement of the weight W. This Lm is obtained by the following equation (2).

[0036]

[Number 2] _{Lm = hm '/ (h 2} -h 1)

FIG. 3B shows a case where the cross section of the inclined surface U is constituted by two broken lines. In this case, the thickness of the block BLu at the point where the two polygonal lines intersect is defined as h _3, and the height of the inclined surface U of the portion where the thickness is h ₂ in the z-axis direction is L ₁ ,
The height of which is obtained by subtracting the L ₁ from L and L _2. FIG. 3B
Does not have the letter L. Other dimensions are
It is the same as FIG. 3A. Thus, the heights are L ₁ and L ₂
Lm in the range of the portion is given by the equation of Expression 3. The case of FIG. 3B is suitable for a case where the accuracy of the main moving portion of the moving amount of the moving object is measured higher than the accuracy of the remaining portion when the moving amount of the moving object is slow.

[0038]

[Number 3] L ₁ of the _{range: Lm = hm / (h 3} -h 1) of × L ₁ L _{2 range: Lm = hm / (h 2} -h 3) × L 1

FIG. 3C shows the cross section of the inclined surface U as a curve (arc,
(Parabolic curve, polynomial curve, etc.). Lm in this case is calculated by substituting the coefficients of the mathematical formula of the curve.
The case of FIG. 3C is suitable when the moving amount of the moving body changes in a curved line (such as an arc, a parabola, or a polynomial curve). In this case, it becomes a curved jig rather than an inclined jig. still,
3B and 3C are shown for reference.

Next, the specific structure of the optical laser displacement meters 2 and 3 in the displacement measuring device of the specific example of FIG. 1 will be described with reference to FIG. The drive signal from the input terminal 11 is supplied to the semiconductor laser 13 through the drive circuit 12, and the semiconductor laser 13 is driven. The laser light from the semiconductor laser 13 is condensed through the light projecting lens 14 to form a pinhole (for example, a diameter of 0.001 mm or less), and the measurement target 1 within the displacement measurement range around the reference position.
Irradiate 5 The reflected laser light from the measuring object 15 is condensed through the light receiving lens 16 and enters the optical position detecting element 17. In this optical laser displacement meter, the position of the measurement object 15 with respect to the reference position is detected using the principle of triangulation, and the position detection signal is output to the output terminal 19 through the amplifier circuit 18. This optical laser displacement meter
A minute displacement amount of the measurement object can be measured with high accuracy and high-speed response.

The length from the end face of the optical laser displacement meter to the reference position in FIG. 4 differs depending on the type of the optical laser displacement meter, but in the case of the specific example, it is 30 mm. When the meter measures the displacement of points Us and Ue on the displacement measurement trajectory of the inclined surface U of the inclined jig in FIG. 2, the distance from the end face of the optical laser displacement meter to the points Us and Ue is 30 mm-3 mm. And 30 mm + 3 mm.

Incidentally, displacement measuring devices are roughly classified into a contact type and a non-contact type. However, when the object to be measured must not be subjected to an external force, or when it is difficult to contact the object to be measured. Will use a non-contact measuring device. Non-contact type displacement measuring devices include high-frequency magnetic fields, static electricity, ultrasonic waves,
There is a displacement measuring device using laser light.

[0043] The displacement measuring device used in the drop-type impact test device is limited to all materials and colors expected to be used in the test sample because the measurement object is not constant due to various tests. The above-mentioned optical laser displacement meter was selected as a displacement measuring device which can detect a pinpoint portion and satisfies various conditions such as high accuracy and high-speed response with respect to measurement performance.

Next, with reference to FIG. 6, a description will be given of a comparison between a displacement amount measurement of a specific example of the embodiment of the present invention and a conventional displacement amount measurement. In both measurements, the weight started to contact the specimen at an initial speed of 10 m / sec, and the weight applied an impact load to the specimen to deform or destroy the specimen, so that the kinetic energy of the weight was reduced. 80m of weight absorbed by
Let us consider a case where the vehicle stops after falling by m. The measuring range of the moving amount of the weight of the optical laser displacement meter used in the conventional example is 20.
0 mm and the response speed is 0.9 kHz. In contrast,
The measuring range of the movement amount of the inclined surface of the inclined jig of the optical laser light displacement meter used in the specific example is 6 mm, and the response speed is 50 k.
Hz. The frequency of the sampling clock of the A / D converter in the memory of the conventional example and the specific example is 100 kHz.

The vertical axis in FIG. 6 indicates that the height of the top surface of the specimen from the floor when the weight contacts the specimen is 200 mm,
The amount of breakage or deformation of the specimen is shown as the amount of displacement expressed as the amount of drop of the weight, and the conversion factor of the device developed so that the conventional example and the specific example (the present invention) have the same numerical value is determined. I have. The horizontal axis in FIG. 6 indicates the elapsed time as 10 ⁻³ sec (msec).
It is expressed in units of

In the conventional example, the step-shaped line indicates that the detection interval of the displacement measurement data is the left end of each step, and thereafter, the previous data is detected until the value of the left end, which is one step lower at the 112th point, is detected. Since the data is continuously output, the data is recorded as if the displacements were the same, depending on the sampling speed (100 kHz) of the memory.

Although the curve of the specific example (the present invention) actually has a stepped shape, it has a new stepped shape at every two points.

FIG. 7 shows the actual detected displacement of the optical laser displacement meter used in the specific example (the present invention) and the detected output voltage value. The vertical axis represents the detection output voltage (V), which is ± 5 V with respect to the rated measurement amount (± 3 mm) of the displacement meter. The horizontal axis indicates the actual displacement (mm). A broken line indicates a detection output (± 5 V / ± 3 mm) with respect to a detection amount when the inclined surface U of the inclined jig is measured in the x direction. The thick solid line is a line for explanation in the case where the data measured by the dashed line is converted by the arithmetic processing unit (computer) 7 into ± 100 mm / ± 5 V as the movement amount of the weight.

A comparison will be made between the conventional displacement measuring device and the moving amount measuring device of the specific example. The detection interval for the falling speed of the weight in the specific example is 10 m / 50,000 s ⁻¹ = 0.0002 m /
s, and one point is detected at an interval of 11.1 mm / s in the conventional example, but is improved to a highly accurate detection interval of 0.2 mm / s in the specific example. Further, the data stored in the memory 6 becomes 100 kHz / 50 kHz = 2, and new detection data is updated between two points. If the data can be acquired at this interval, even if the data of one intermediate point that could not be detected is interpolated and used, the decrease in accuracy hardly causes a problem.

The maximum value of the error due to the calculation of the actual displacement with respect to the rated output of the displacement meter due to the tilt jig is 200.
mm / 6mm = 33.3 times, and the detection resolution is 0.0
005mm and extremely high precision, 0.0005 × 3
3.3 = 0.0166 mm, and the moving amount of the weight is 200
It does not affect the accuracy for mm. For this reason, it is possible to measure the amount of movement of a wide range of weights and moving objects that could not be measured conventionally by using a combination of an optical laser displacement meter with high response speed, a tilt jig, and a high-speed memory. It became. Further, if the length and the inclination angle of the inclined jig are changed (however, the dimension of h in FIG. 2 is a maximum of 6 mm), it is possible to measure a wider moving amount.

As described at the beginning, in the drop-type impact test apparatus, an impact is applied by a weight that falls on the specimen on the floor surface, or the impact is attached to the weight, and it falls together with the weight to fall on the floor. The main purpose is to calculate the impact energy according to the amount of deformation of the specimen that has been impacted by colliding with the surface. Therefore,
The weight falls freely and starts contacting the specimen on the floor surface.The impact load of the weight causes the specimen to absorb the impact energy of the weight and deform, and finally the weight falls. Until the stop, the amount of falling of the weight every predetermined time, that is,
The above-described impact energy can be calculated by measuring the displacement amount and the acceleration of the weight (or the load applied to the specimen) and calculating the sum of the products by the computer 7. The calculation result is displayed on the display device 8 or the printer 9. The measurement of the acceleration of the weight and the load applied to the specimen will be described in the following description of other measurements. If the amount of drop of the weight every predetermined time, that is, the amount of displacement and the acceleration of the weight (or the load applied to the specimen) can be measured with high measurement resolution, a highly accurate value of impact energy is calculated. Can be. In the past, the measurement of the acceleration of the weight and the load applied to the specimen could be measured with high measurement resolution.However, the displacement amount of the weight every predetermined time should be measured with high measurement resolution. Was difficult. However, the displacement amount measuring device of the present invention makes it possible to measure the displacement amount at predetermined time intervals with high measurement resolution.

Next, the displacement amount (displacement amount) of the weight every predetermined time is measured by the displacement amount measuring apparatus of FIG. 1 until the weight impacts the specimen and deforms the specimen. At the same time, the measurement is performed and the measurement output is stored in the memory. The measurement by the other measurement device and the measurement output of the measurement by the measurement device are used to describe the detection at the time when the weight falls and starts to contact the specimen. .

First, the load cell will be described. The load cell measures the weight and applied force of an object, and is a measuring instrument that measures not only a static weight of an object but also a specified direction component of an installed measurement point together with a time history. A common load cell is a load cell. The principle of this load cell is to detect the amount of deformation of the built-in sensitive part due to load, bending, compression, etc. with a strain gauge and output it as a specified voltage value for the load,
A measuring instrument for distortion detection can be used.

The installation location of the load cell varies depending on the shape, dimensions, and measurement purpose of the specimen. For example, when the specimen is installed on the floor, the load cell is inserted between the specimen and the floor. Then, the weight is measured until the weight starts to contact the specimen, the specimen deforms and the weight stops falling. If the specimen is attached to the weight, a load cell is installed on the floor where the specimen lands. In either case, the load is detected with the vertical downward force as the positive direction.
Then, the point in time when the load starts to increase is detected as the point in time when the weight falls and starts contacting the specimen on the floor or the point in time when the specimen attached to the weight starts contacting the floor. I can do it.

Next, the distortion measurement will be described. For the strain, the stress at a specified portion of the specimen is measured, and the stress distribution, vibration, and strength related to the deformation of the entire specimen are evaluated. For the measurement of the strain, for example, a strain gauge having a length of 1 mm is used. The principle of the strain gauge is that the metal resistance element is adhered to the surface of the object to be measured, and the resistance value increases when the metal resistance element expands, and decreases when the metal resistance element compresses. Is inserted into two sides of a Wheatstone bridge circuit composed of a resistor. In this case, a prescribed voltage is applied between two diagonal points on one side of the bridge circuit, and a voltage is generated between two diagonal points on the other side. When the resistances of the four sides have the same resistance value, the voltage between the other two diagonal points is 0 V, and when the resistance value of the strain gauge incorporated in the bridge circuit changes, the voltage between the two diagonal points is changed. And its voltage is
Positive and negative voltages are generated as the resistance value of the strain gauge increases or decreases. If the positive and negative voltage values are measured by the dedicated signal conditioner, the compression and expansion values of the measured object can be detected by distortion amounts. Therefore, when the strain began to increase due to the strain gauge attached to this specimen,
It can be detected as the time when the weight falls and starts to contact the specimen on the floor surface or the time when the specimen attached to the weight starts to contact the floor surface.

Next, measurement of acceleration will be described. The measurement place of the acceleration is more than ten places of the weight or the specimen. Although there are various types of acceleration measurement models, the detection range of the sensor is from several G to about 1000 G, and the impact durability sensitivity is 10
000G or more is used. Also, in order to minimize the effect of the additional load attached to the weight or specimen, the sensor must be small and light in weight, and must have a fast response (100 kHz).
z or more) is also required. As an accelerometer that satisfies these conditions, a piezo-type charge element is preferable. The principle of this piezo charge element is to adhere a movable mass to the piezo charge element, and the movable mass that vibrates according to the applied acceleration defines the amount of charge generated when the attached piezo charge element is compressed or pulled. Measure with a dedicated signal conditioner that converts to a voltage corresponding to G. Then, by the piezo-type charge element attached to the weight or the specimen, the time point of the first large change in the acceleration is determined when the weight falls and starts to contact the specimen on the floor or attached to the weight. It is detected as the time when the test specimen that has come into contact with the floor surface.

Next, displacement measurement will be described. In this case, it is necessary to simultaneously detect the deformation amount of the specimen and its speed history. The deformation of the specimen is complicated and cannot be measured by specifying the whole. As one method, the movement of a designated point can be tracked from continuous recording by a high-speed digital camera. However, this data accuracy is regulated by the pixel size, and 256 × 2
56 points. In other words, even if the point recorded at the top of the screen is deformed to the bottom, the resolution is 1/256. Then, the deformation of the specimen in the vertical downward direction is measured. The load energy can be obtained from the relationship between the displacement and the acceleration or the load. In addition, the displacement amount is indicated by stress, strain, acceleration, etc.,
Basic important data used for evaluation. When the weight falls and starts contacting the specimen on the floor from the point of change in vertical downward displacement by the displacement meter attached to the specimen on the floor or the It is detected as the point at which the specimen attached to the weight starts contacting the floor surface.

When measuring the load, strain, acceleration and displacement,
When the weight falls and starts contacting the specimen on the floor, or when the specimen attached to the weight starts contacting the floor, the maximum value that changes rapidly from the moment of contact is detected. Therefore, any measurement of load, strain, acceleration and displacement can be adopted, but since a time problem of signal propagation occurs, a signal near the initial contact is selected as a reference signal. .

The drop impact test is generally completed instantaneously (within a few seconds at most), and the measurement of load, strain, acceleration or displacement is performed simultaneously with the drop of the weight. Since a dedicated signal conditioner or the like is used for each of the load, strain, and acceleration measuring devices, the measurement output is an analog voltage.

The model of the measuring instrument is selected by considering the response speed, detection amount, resolution, sensor weight, size of the detection point, compatibility with the object to be measured, recording time, etc. The determination is made in consideration of the fact that it can be optimally detected. Also, using the measurement of load, strain, acceleration, and displacement together, when the weight falls and starts to contact the specimen on the floor, or the specimen attached to the weight starts to contact the floor. When detecting the point in time, it is necessary to integrate the data into an easy-to-handle and integrated system so as not to cause a time lag between all data.

[0061]

According to the first aspect of the present invention, an inclined jig provided with a moving body, an inclined surface attached to the moving body and having a predetermined inclination with respect to a moving direction of the moving body, and the inclined jig An optical laser displacement meter that measures the distance between the inclined plane and the moving surface at predetermined intervals, and an optical laser displacement meter that measures the distance from one point of the moving body to another point. Calculate the difference between adjacent distances with the inclined surface at predetermined time intervals, multiply each difference by a proportional coefficient corresponding to the predetermined inclination of the inclined surface, and calculate the displacement amount of the moving body at predetermined time intervals. And a calculating means for calculating the displacement of the moving body, the displacement measuring range of the moving amount of the moving body can be widened, and the displacement measuring apparatus can measure the displacement of the moving body every predetermined time with a high resolution.

According to the second aspect of the present invention, the weight that can freely fall and the weight that is located on the floor surface (or is attached to the weight)
The distance between the test specimen and the inclined jig attached to the weight and having an inclined surface having a predetermined inclination with respect to the falling direction of the weight, and the inclined surface accompanying the movement of the inclined jig is set at predetermined time intervals. With the optical laser displacement meter to be measured, and with the movement of the weight from one point to another point, the distance between each adjacent distance between the inclined surface measured every predetermined time measured by the optical laser displacement meter. Calculation means for calculating the difference, multiplying each difference by a proportional coefficient according to a predetermined inclination of the inclined surface, and calculating a displacement amount of the weight every predetermined time. It is possible to obtain a displacement measuring device of a drop-type impact test device having a wide measurable range and high resolution for measuring the displacement of the weight every predetermined time.

According to the third aspect of the present invention, there is provided a moving body, an inclined surface attached to the moving body, having a predetermined inclination with respect to the moving direction of the moving body, and a plane parallel to the moving direction of the moving body. A first optical laser displacement meter for measuring the distance between the inclined jig and the inclined surface associated with the movement of the inclined jig at predetermined time intervals, and a distance between a plane associated with the movement of the inclined jig for a predetermined time A second optical laser displacement meter that measures each time, and a plane measured at a predetermined time interval by the second optical laser displacement meter with the movement of the moving body from one point to another point. A difference between each distance between the respective distances and the respective distances between the inclined planes measured by the first optical laser displacement meter and corresponding to the respective distances at predetermined time intervals is calculated. The difference between adjacent differences is calculated, and for each difference,
Calculating means for calculating a displacement amount of the moving body at predetermined time intervals by multiplying by a proportional coefficient corresponding to a predetermined inclination of the inclined surface, so that a measurable displacement range of the moving amount of the moving body is wide, and Has a high measurement resolution of the displacement amount at every predetermined time, and corrects the error of the displacement amount at every predetermined time of the moving body due to the play in the direction of the distance between the moving body and the first optical laser displacement meter. As a result, it is possible to obtain a displacement amount measuring device capable of measuring the displacement amount of the moving body every predetermined time with high accuracy.

According to the fourth aspect of the present invention, the weight that can freely fall and the weight that is located on the floor (or is attached to the weight)
A test object, an inclined jig attached to the weight, having an inclined surface having a predetermined inclination with respect to the falling direction of the weight and a plane parallel to the moving direction of the weight, and an inclined surface accompanying the movement of the inclined jig A first optical laser displacement meter for measuring the distance between the optical disc and the plane associated with the movement of the tilt jig at predetermined time intervals; Along with the movement of the weight from one point to another point, each distance between the plane and the plane every predetermined time measured by the second optical laser displacement meter corresponds to each of the distances. Calculating the difference between each distance measured by the first optical laser displacement meter and the inclined surface every predetermined time,
The difference between adjacent ones of the respective differences is calculated, and each difference is multiplied by a proportional coefficient according to a predetermined inclination of the inclined surface,
Since the calculation means for calculating the displacement amount of the weight every predetermined time is provided, the measurable displacement range of the movement amount of the weight is wide, and the measurement resolution of the displacement amount of the weight every predetermined time is high, and By correcting an error of the displacement amount of the weight every predetermined time due to the play in the direction of the distance between the weight body and the first optical laser displacement meter, the displacement amount of the weight every predetermined time is increased. It is possible to obtain a displacement measuring device of the drop impact test device that can measure with high accuracy.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a circuit configuration of a displacement measuring device of a drop impact test device according to a specific example of an embodiment of the present invention.

FIG. 2 is a perspective view showing an example of a tilt jig used in the displacement measuring device of the specific example of FIG.

FIG. 3 is a cross-sectional view showing a vertical cross-sectional shape of a block BLu of the inclined jig in FIG. 2 and a modified example thereof.

FIG. 4 is a schematic diagram illustrating an example of an optical laser displacement meter used in the displacement measuring device of the specific example of FIG. 1;

5 is a layout diagram showing mechanical components of a displacement measuring device of the drop impact test device of the specific example of FIG. 1 and an explanation of its operation.

FIG. 6 is a characteristic diagram showing an example of displacement measurement according to the present invention and a conventional example.

FIG. 7 is a characteristic diagram showing a substantial displacement amount according to the present invention with respect to a rated output of the displacement meter.

FIG. 8 is a layout diagram showing a conventional displacement measuring device in a drop-type impact test device.

FIG. 9 is a block diagram showing a conventional displacement measuring device.

[Explanation of symbols]

1 inclined jig, inclined plane of U inclined jig, vertical plane of V inclined jig, 2, 3 optical laser displacement meter, 4, 5 displacement / signal voltage converter (controller), 6 memory, 7
Computer, 8 display device, 9 printer.

Claims (4)

(57) [Claims] 1. A movable body, an inclined jig attached to the movable body, the inclined jig having an inclined surface having a predetermined inclination with respect to a moving direction of the movable body, and the inclined surface accompanying the movement of the inclined jig. An optical laser displacement meter that measures the distance between the moving object at predetermined time intervals, and with the movement of the moving body from one point to another, measured by the optical laser displacement meter at each of the predetermined time intervals. A difference between adjacent distances from the inclined surface is calculated, and each difference is multiplied by a proportional coefficient according to the predetermined inclination of the inclined surface to obtain a displacement amount of the moving body at each predetermined time. And a calculating means for calculating the displacement amount. 2. A weight that can be freely dropped; a specimen located on a floor surface (or attached to the weight); and a specimen attached to the weight, which is provided in a predetermined direction with respect to the falling direction of the weight. An inclined jig having an inclined surface having an inclination of; an optical laser displacement meter for measuring a distance between the inclined surface along with the movement of the inclined jig at predetermined time intervals; and With the movement to the point, the difference between each adjacent distance between the slope and the predetermined time, measured by the optical laser displacement meter, is calculated,
Calculating means for multiplying each of the differences by a proportional coefficient according to the predetermined inclination of the inclined surface to calculate a displacement amount of the weight every predetermined time. Device for measuring the amount of displacement. 3. A movable body, an inclined jig attached to the movable body, having an inclined surface having a predetermined inclination with respect to the moving direction of the movable body, and a plane parallel to the moving direction of the movable body, and the inclined jig. A first optical laser displacement meter for measuring a distance between the jig and the inclined surface at predetermined time intervals, and a distance between the plane and the inclined jig movement at predetermined time intervals. A second optical laser displacement meter to be measured; and the plane at every predetermined time, measured by the second optical laser displacement meter with the movement of the moving body from one point to another point. And a difference between each of the distances and the respective distances between the respective inclined planes corresponding to the respective distances, which are measured by the first optical laser displacement meter, at predetermined time intervals. Calculating, calculating the difference between adjacent ones of the respective differences, and calculating Is multiplied by the proportional coefficient corresponding to the predetermined inclination of the inclined surface, displacement measuring apparatus characterized by having a calculating means for calculating an amount of displacement of each said predetermined time of the moving object. 4. A weight that can freely fall, a specimen located on a floor surface (or attached to the weight), and a test piece attached to the weight and defined in a falling direction of the weight. An inclined jig having an inclined surface having an inclination of? And a plane parallel to the moving direction of the weight, and a first optical type for measuring a distance between the inclined surface accompanying the movement of the inclined jig at predetermined time intervals. A laser displacement meter, a second optical laser displacement meter for measuring a distance between the plane with the movement of the tilt jig at every predetermined time, and a movement of the weight from one point to another point Accordingly, each distance between the plane and the plane every predetermined time measured by the second optical laser displacement meter, and the first optical laser displacement meter corresponding to each distance. Between each of the distances from the inclined surface at every predetermined time measured by Calculate the difference, calculate the difference between adjacent ones of each difference, multiply each difference by a proportionality coefficient according to the predetermined inclination of the inclined surface, the weight of the weight every predetermined time A displacement amount measuring device for a drop-type impact test device, comprising: a calculating means for calculating a displacement amount.