JP5845012B2 - Load measuring device for impact load measurement and collision load measuring method - Google Patents

Description

The present invention relates to a load measuring device, a shock load to be used in particular essential fast definitive to deformation tensile load or compressive load the car structure characterization of the impact absorbing member for a representative, that is, the measurement of the impact load The present invention relates to a measurement load measuring device and a collision load measuring method using the same .

In the automobile industry, the development of a vehicle body structure that can reduce injury to passengers during a collision is an urgent issue, and in order to optimize the collision deformation behavior of the vehicle body, deformation of individual members and their combined structures It is extremely important to understand the characteristics.
Therefore, conventionally, characteristic evaluation of the member has been performed by a quasi-static method in which the member is deformed at a low speed using a large compression tester or the like.

However, actual collision deformation occurs at high speed, which is different from behavior under quasi-static load. In particular, it is known that buckling, which is important in a thin plate structure often used in automobiles, behaves differently depending on whether the load is dynamic or quasi-static.
For this reason, in order to grasp the dynamic deformation characteristics, a drop weight test, that is, a test that causes a drop weight to collide with a fixed member from the top to cause a dynamic deformation is performed. It was trying to be close to the deformation.

However, since it is necessary to evaluate the absorbed energy at the time of impact deformation of the member for characteristic evaluation, the evaluation of the absorbed energy requires measurement of the crush distance of the member and the crushing load at that time. In a typical test, it was actually difficult to measure the crush load.
That is, when a dynamic load is measured with a load cell that is generally used in a normal quasi-static test, the impact elastic wave reflects and propagates through the load cell during measurement, and the load resulting from the propagation of the impact elastic wave Therefore, there is a problem in that the impact elastic wave affects the measurement of the measurement load, which makes it impossible to measure the true load of the measurement load.
Furthermore, in recent years, not only tests for individual parts but also collision tests with structures that combine multiple parts have become active, and support for collision tests in which the size of the specimen changes in a complex manner depending on the combination of parts. Therefore, the test jigs are individually designed and manufactured, and there is a problem that a long design and manufacturing period and a large cost are required until the test is performed.

  Regarding the dynamic load measuring method as described above, in order to measure the stress-strain relationship of the material, for example, Patent Document 1 discloses the action of the dynamic load when measuring the dynamic deformation characteristics of the specimen. In an apparatus in which the start point and its support structure are arranged linearly, the support start point, test body, load detection unit, load detection unit support structure are arranged in this order, and the load detection unit is a circle. It is columnar, and the ratio of the diameter D (mm) to the length L (mm) satisfies 0.3 ≦ L / D ≦ 3, and (the cross-sectional area of the load detection unit) <(the load detection unit A load measuring device satisfying the cross-sectional area of the support structure is shown. In addition, when it is necessary to support the test body, the action starting point, the test body, the support section of the test body, the load detection section, and the support structure are arranged in this order, and (cross-sectional area of the load detection section) <( A load measuring device that satisfies the condition of the cross-sectional area of the support portion of the test body is described.

  Although the load measuring apparatus described in Patent Document 1 can accurately perform dynamic load detection, since only one load detection unit that detects a load is provided, When an eccentric load is applied to the load detection unit, a complicated bending moment is generated. In particular, in the case of a test on a complex structure that has been increasing in recent years, it is often impossible to specify at which position the tensile load or the compressive load acts, and therefore there is a high possibility that an eccentric load acts on the load detection unit.

  At this time, even in the load measuring apparatus described in Patent Document 1, it is possible to measure the load acting in the axial direction of the load detection unit, but when an eccentric load is applied, as described above. In addition, since a complicated bending moment is generated in the load detection unit, it is considered that accurate load measurement cannot be performed due to the influence of the bending moment. There is also a problem that the measurement accuracy is likely to change depending on the position of the strain gauge attached to the load detection unit. Furthermore, since stress concentrates on a part of the load detection unit due to the eccentric load and may be intensively deformed on a part of the load detection unit, the load detection unit is supposed to be elastic deformation originally. There is a possibility that plastic deformation may occur, and it is considered that accurate load measurement cannot be performed.

JP 2006-284514 A

The technical problem of the present invention, high-speed high-precision definitive to deformation tensile load or compressive load, i.e. when measuring the impact load, can also accurately measure the load acts even eccentric load, and members alone Load measuring device for impact load measurement that can reduce the time and money costs of designing and manufacturing jigs for load measuring devices in a wide range of impact tests from structures to combinations of multiple members , and using the same It is to provide a collision load measuring method .

In order to solve the above-described problems, the load measuring device for measuring an impact load according to the present invention is provided at each of a cylindrical load detecting unit for measuring a tensile load or a compressive load, and both ends in the axial direction of the load detecting unit. A pair of holding portions, the pair of holding portions and the load detection portion are integrated, and the cross-sectional area of the cross section perpendicular to the axis of the load detection portion of the pair of holding portions is the axis of the load detection portion. A plurality of load measuring members formed larger than the cross-sectional area of the orthogonal cross section, and a holding part on one side of each load measuring member are in close contact with each other, and are connected by bolts , to apply a tensile load or a compressive load. A contact member and a single support member in which the other holding portion of each load measuring member is in close contact and connected by a bolt , and each of the load measuring member, the contact member, and the support member is an iron Young's modulus. Young's modulus above Made from the material, the plurality of load measuring member, between the contact member and the support member, the axial direction of the load detection unit is being arranged in parallel so as to be parallel to each other, the contact member and The support member is formed such that a cross-sectional area of a cross section perpendicular to the axis of the load detection unit of the load measurement member is larger than the axis of each load detection unit, and the holding unit on one side of each of the load measurement members and The holding parts on the other side are arranged in a state where the holding parts of the adjacent load measuring members are in close contact with each other.
Moreover, the load measuring device for impact load measurement of this invention can make the said holding | maintenance part polygonal prism shape of planar view.
Furthermore, the collision load measuring method of the present invention has a cylindrical load detecting unit for measuring a tensile load or a compressive load, and a pair of holding units respectively provided at both ends in the axial direction of the load detecting unit. The pair of holding portions and the load detection portion are integrated, and the cross-sectional area of the cross section orthogonal to the axis of the load detection portion of the pair of holding portions is larger than the cross-sectional area of the cross section orthogonal to the axis of the load detection portion. A plurality of formed load measuring members, a single contact member for applying a tensile load or a compressive load, in which a holding portion on one side of each load measuring member is in close contact and connected by a bolt , and each load measuring member The holding part on the other side is in close contact with a single support member connected by a bolt , and each load measuring member, contact member and support member are each made of a material having a Young's modulus equal to or higher than the Young's modulus of iron, Multiple loads above The measurement member is arranged in parallel between the contact member and the support member so that the axial directions of the load detection units are parallel to each other, and the contact member and the support member are the load measurement member. The cross-sectional area of the cross section orthogonal to the axis of the load detecting section is larger than the cross-sectional area of the cross section orthogonal to the axis of each load detecting section, and the holding section on one side of each of the load measuring members, The other holding part measures a collision load applied to the contact member using a load measuring device arranged in a state where the holding parts of the adjacent load measuring members are in close contact with each other. Is.

  According to the present invention, a plurality of load measuring members provided with a load detection unit are arranged in parallel between the contact member and the support member so that the axial directions of the load detection units are parallel to each other. Even if an eccentric load is applied to the contact member, the load can be measured with high accuracy by the load detection unit of the load measuring member directly under or near the position where the eccentric load is less affected by the bending moment. In addition, each load measuring member is formed so that the cross-sectional area of the cross section orthogonal to the axis of the load detection section in the pair of holding sections is larger than the cross-sectional area of the cross section orthogonal to the axis of the load detection section. When an eccentric load is applied to a member, the load detectors of each load measuring member are elastically deformed and do not interfere with the load detectors of other load measuring members due to contact or the like. Further, plastic deformation due to the concentration of deformation due to the eccentric load is prevented.

Further, the pair of holding portions of each load measuring member and the load detecting portion are integrally formed, and the pair of holding portions, the contact member, and the supporting member are formed from a cross-sectional area of the cross section perpendicular to the axis of the load detecting portion. Since the cross-sectional area of the cross section orthogonal to the axis of the load detecting portion in FIG. 2 is formed, reflection / interference of stress waves in the load detecting portion of each load measuring member can be promoted. Thereby, early saturation of the stress wave in the load detection unit related to the load to be measured can be achieved, and the influence of the disturbance of the propagation of the stress wave in the load detection unit can be eliminated. As a result, it becomes possible to measure a high-precision tensile load or compressive load in a wide range of deformation speeds including high-speed deformation that is essential for characteristic evaluation of impact absorbing members typified by automobile structures.
In addition, the entire structure is configured as a unit consisting of a load measuring member with a load detector with a small cross-sectional area in the horizontal section, so even a large-scale structure test can be handled by simply increasing the number of units. This can greatly reduce the time and money costs due to the design and production of complex jigs.

It is a front view which shows typically the load measuring device which concerns on this invention. It is the same top view. It is (a) front view and (b) AA sectional view showing typically a load measuring member used in the present invention. It is explanatory drawing explaining the raise process of the load of a load detection part. It is explanatory drawing of each load measuring device of an Example. It is the graph which compared the measurement result about the load measuring device which concerns on this invention, and the conventional load measuring device.

1 to 3 show an embodiment of a load measuring device according to the present invention. The load measuring device according to this embodiment includes a plurality of load measuring members 1 each including a load detecting unit 4 extending in a vertical direction. , A single contact member 2 that makes the test body contact and applies a tensile load or a compressive load, and a single support member 3 that is fixed to a rigid body or the like and supports the load measuring member at the time of the test.
The plurality of load measuring members 1 are arranged in parallel between the contact member 2 and the support member 3 so that the axes of the load detection units 4 are parallel to each other, and as a whole, The load measuring member 1 is held in a state of being sandwiched between the contact member 2 and the support member 3.

In this embodiment, the contact member 2 is disposed on the upper side of the load measuring member 1 and the support member 3 is disposed on the lower side.
In addition, as shown in FIGS. 1 and 2, the load measuring device according to this embodiment includes a total of 36 load measuring members 1 each having six rows in the horizontal direction and six rows in the vertical (depth direction) in plan view. As a result, the load measuring apparatus as a whole has a structure including 36 load detection units 4. Note that the contact member 2 constituting the load measuring apparatus of this embodiment is described above. The supporting member 3 and each load measuring member 1 (that is, the load detecting unit 4 and the upper side holding unit 5 and the lower side holding unit 6 described later) are all equivalent materials, that is, having the same elastic modulus and density. Is formed of things.

  As shown in FIG. 3, each of the load measuring members 1 includes a single load detecting unit 4 formed in a solid columnar shape rising in the vertical direction, and both end portions in the axial direction of the load detecting unit 4, In other words, the upper and lower holding parts 5 and 6 are provided as a pair of upper and lower holding parts respectively provided at both upper and lower ends of the load detection part. Therefore, each load measuring member 1 is configured such that the load detecting unit 4 is sandwiched between the upper side holding unit 5 and the lower side holding unit 6 as a whole, and the axis of the load detecting unit 4 extends in the vertical direction. It has become.

A strain gauge (not shown) is affixed to the outer peripheral surface of the load detection unit 4, and load detection can be calculated from the surface strain measured by the strain gauge. Here, the reason why the load detection unit 4 is a solid column is to make the load distribution in the cross section uniform, and as a result, the accuracy of load measurement using a strain gauge is enhanced.
This point will be described in detail. For example, when the load detection unit is in the shape of a prism, when an eccentric load is applied to the load detection unit, stress concentrates on the corner and is locally applied to the corner. Deformation is likely to occur, and the deformation is a complex deformation in which compression deformation and shear deformation are mixed. Since stress waves, which will be described in detail later, change in speed due to deformation of a propagating object, when such a complicated deformation occurs in the load detection unit, the load detection unit is subjected to stress waves having different propagation speeds. Will pass with a time difference. Such a time difference between stress waves appears as noise during load detection, and as a result, highly accurate load measurement is hindered. Furthermore, if the stress is concentrated locally at the corners or the like, there is a very high possibility that plastic deformation, which should not be a load detection unit of this type, will occur. Accordingly, it can be said that a shape that easily causes local deformation such as a prismatic shape is extremely unsuitable as a load detection unit.
Therefore, in the present invention, the load detection unit is a solid columnar shape, and the load distribution in the cross section is made uniform so that local deformation concentration is prevented and simple deformation is generated as much as possible. The change of the velocity of the stress wave in the detection unit is prevented, the stress wave is prevented from passing with a time difference, and noise at the time of load detection is eliminated.
The length in the axial direction of the load detector 4 is preferably as short as possible within the range where the strain gauge can be attached. This allows time for the stress wave to propagate throughout the load detector 4 during load measurement. Since it can reduce, the early saturation in the load detection part 4 of the said stress wave mentioned later can be promoted further.

Further, in the present embodiment, the upper side holding part 5 and the lower side holding part 6 are each formed in a substantially square cubic shape in plan view rising in the vertical direction, and have the same shape. Yes. And between the said contact member 2 and the support member 3, it arrange | positions in the state which the upper side holding | maintenance parts 5 of the adjacent load measuring members and the lower side holding | maintenance parts 6 contact | adhered, respectively.
Therefore, a total of 36 load measuring members 1 in 6 rows × 6 rows between the contact member 2 and the support member 3 are the upper side holding portion 5 and the lower side holding portion 6 of all these load measuring members 1. In this manner, the upper and lower end surfaces are arranged in a substantially square shape in plan view.

Further, in the load measuring member 1, the load detecting portion 4, the upper side holding portion 5 and the lower side holding portion 6 are integrally formed by cutting or the like, and all the load measuring members 1 have the same shape and the same size. Has become. The load detection unit 4 and the upper side holding unit 5 and the lower side holding unit 6 are integrally formed in the load measuring means 1, that is, the load detection unit 4, the upper side holding unit 5 and the lower side holding unit 6 In order to suppress the generation of vibrations due to the propagation of stress waves at the joint portion, the generation of noise due to the vibrations during load measurement is prevented, thereby improving the accuracy of load measurement.
Furthermore, the load measuring member 1, that is, the load detecting unit and the upper side holding unit 5 and the lower side holding unit 6 are made of a material having a high Young's modulus as a whole, for example, iron or the like. The propagation speed of can be increased as much as possible.
Further, as shown in FIG. 1, the horizontal cross sections Ah ₁ and Ah ₂ of the horizontal cross sections of the upper side and lower side holding parts 5 and 6, that is, the cross sections orthogonal to the axis of the load detection part 4, The horizontal cross section is formed larger than the cross sectional area Ak of the cross section orthogonal to the axis of the load detection unit 4.

The contact member 2 is formed in a plate shape (cubic shape) having a substantially square shape in plan view, and the upper surface side is a contact surface that contacts the test body, while the lower surface side has the load measuring member. 1 is accommodated and fixed.
The plate surface of the contact member 2 is substantially the same as or slightly larger than the upper end surface of the substantially square shape in plan view formed by the assembly of the upper side holding portions 5 of all the load measuring members 1. Thus, the upper side holding portions 5 of all the load measuring members 1 are accommodated on the lower surface side without protruding.
The contact member 2 and each load measuring member 1 are connected by a detachable bolt (not shown) that penetrates the contact member 2 and reaches the upper holding portion 5 of the load measuring member 1. As a result, when the bolt is fixed, the lower surface of the contact member 2 and the upper end surface of the upper side holding portion 5 of each load measuring member 1 are in close contact with each other in a fixed state.

The support member 3 is formed in a substantially square plate shape (cubic shape) in plan view that is substantially the same shape as the contact member 2, and the load measuring member 1 is placed and fixed on the upper surface side. .
The plate surface of the support member 3 is substantially the same as or slightly larger than the lower end surface of the substantially square shape in plan view formed by the assembly of the lower side holding portions 6 of all the load measuring members 1 (this embodiment In the case of the form, it has the same size as the contact member 2), and the lower side holding portions 6 of all the load measuring members 1 are accommodated on the lower surface side without protruding.
The support member 3 and each load measuring member 1 are connected by a detachable bolt (not shown) that penetrates the support member 3 and reaches the lower side holding portion 6 of the load measuring member 1. Thus, when the bolt is fixed, the upper surface of the support member 3 and the lower end surface of the lower side holding portion 6 of each load measuring member 1 are connected to each other in a stationary manner in a state where they are in close contact with each other.

By the way, the contact member 2 and the support member 3 have the horizontal cross sections, that is, the cross-sectional areas As ₁ and As _{2 of} each cross section orthogonal to the axis of the load detection unit 4 of the load measurement member 1, respectively. It is formed larger than the horizontal cross section, that is, the cross sectional area Ak of the cross section perpendicular to the axis of each load detection unit 4.
Further, the horizontal cross-sectional areas As ₁ and As ₂ of the contact member 2 and the support member 3 are horizontal to the upper and lower side holding portions 5 and 6 of the load measuring member 1 alone due to the configuration of the load measuring device. The cross-sectional areas Ah ₁ and Ah ₂ of the cross section are larger.
Therefore, the cross-sectional areas As ₁ , As ₂ , As ₁ , As _{2 of the} horizontal cross sections of the contact member 2 and the support member 3, the upper and lower holding parts 5, 6 of each load measuring member 1, and the load detection part 4. , Ak are in a relationship of As ₁ = As ₂ > Ah ₁ = Ah ₂ > Ak, and As ₁ and As ₂ are much larger than Ak.

Here, the relationship between the size of the cross-sectional area of each horizontal cross section of the contact member 2 and the support member 3, the upper side and lower side holding portions 5 and 6 of each load measuring member 1, and the load detection unit 4 is As ₁ = As. _The reason why ₂ > Ah ₁ = Ah ₂ > Ak is to complete saturation of stress waves in the load detection unit 1 earlier.
Hereinafter, this point will be specifically described.

When an impact load is applied to the test body, high-speed deformation occurs in the test body. At this time, the tensile load or the compression load f applied to the test body, that is, the load generated on the load measuring member is a step as shown in FIG. It is measured so that the load F reaches 100% after elapse of Δt time. This is because when the stress wave is transmitted through the load detection unit 4, reflection at the end face of the load detection unit 4, interference of stress waves in the load detection unit 4, and the like are repeated, and the stress wave is gradually saturated.
When a dynamic test is performed, the stress wave is first reflected and interfered inside the load detection unit 4 to make the internal deformation uniform. At that time, in order to perform high-speed and high-accuracy load measurement, it is necessary to saturate reflection / interference in the load detector 4 that causes stress wave noise at an early stage.

Therefore, in order to accurately measure the load at the time of high-speed deformation of the specimen, the time Δt at which the load becomes unstable is obtained by saturating the reflection / interference of stress waves in the load detector 4 at an early stage. It is important to shorten it.
In view of this point, the inventors pay attention to a plurality of step portions of the load to be measured, and increase the load corresponding to these step portions relative to the load F to be measured, thereby increasing the load. It was found that the load transmitted to the detector 4 can reach the load F at an early stage and the time Δt can be shortened.

In order to increase the load corresponding to the step relative to the load F, it is effective to increase the reflectance of the stress wave in the load detection unit 4 and saturate the stress wave early. The inventors have found that there is.
Also, when the stress wave travels from a small area to a large area, the reflectivity increases and the reflection increases, and when the stress wave travels from a large area to a small area However, in the area of the large cross-sectional area, the influence of the disturbance of stress wave propagation is very large, but when the process proceeds from the small area to the large area, the influence of the disturbance of stress wave propagation is hardly affected in the small area. I knew I would n’t. Furthermore, it has been found that the greater the difference in cross-sectional area, the greater the stress wave reflectance.

Therefore, in the present invention, the cross-sectional area of the horizontal cross section of the load detector 4 is made the smallest among the members constituting the load measuring member 1, and the upper and lower side holding portions 5, 6 of the load measuring member 1 are further reduced. The cross-sectional areas are increased in the order of the cross-sectional areas of the contact member 2 and the support member 3.
Further, in this embodiment, for each load measuring member 1, the side surfaces of the holding portions 5 and 6 of the adjacent load measuring members 1 are brought into close contact with each other, and the upper side holding portion 5 of each load measuring member 1. And the contact member 2 and the lower holding part 6 and the support member 3 are in close contact with each other. Accordingly, the upper side holding portion 5 and the contact member 2 and the lower side holding portion 6 and the support member 3 are integrated with each other, so that the upper side holding portion located on the upper side of the load detecting portion 4. Difference between the horizontal cross section of the entire section 5 and the contact member 2 and the horizontal cross section of the entire lower side holding section 6 and support member 3 positioned below the load detection section 4 and the horizontal cross section of each load detection section 4 Becomes bigger.
As a result, it is possible to increase / promote reflection of stress waves in the load detection unit 4 and to promote interference, and to saturate the stress waves early. As a result, the time Δt is shortened, and the load detection unit 4 4 enables high-precision load measurement.
Furthermore, by making the cross-sectional area of the horizontal cross section of the load detection unit 4 the smallest, the load detection unit 4 almost eliminates the influence of the disturbance of the propagation of stress waves. Load measurement is possible.

  In the load measuring apparatus having the above configuration, the support member 3 is fixed to a rigid body, and the test body is made to collide with the contact surface of the contact member 2 or the test body is placed on the contact surface. A compressive load or a tensile load is applied to the contact member 2 by applying an impact with a falling weight or the like, and the load is measured by the load detection unit 4 of the load measuring member 1.

At this time, since the plurality of load measuring members 1 are arranged in parallel between the contact member 2 and the support member 3 so that the axial directions of the load detection units 4 are parallel to each other, Regardless of which position load of the contact member 2 is applied, that is, even if an eccentric load is applied to the contact member 2, the load detector 4 of each load measuring member 1 is elastically deformed individually in a substantially vertical direction.
Therefore, the load in the vertical direction to be originally measured is highly accurate by the load detection unit 4 of the load measuring member 1 located immediately below or near the position of the load acting on the contact member 2 where the influence of the bending moment is relatively small. Can be measured.
Moreover, since the cross-sectional area of the horizontal cross section of the load detecting unit 4 is smaller than the cross-sectional areas of the horizontal cross sections of the contact member 2 and the upper and lower holding parts 5 and 6, an eccentric load is applied to the contact member 2. Even if it exists, each load detection part 4 does not interfere with the load detection part 4 of the other load measuring member 1, but each elastically deforms, and thereby plasticity due to concentration of deformation caused by the eccentric load as in the prior art. Deformation is prevented.

  Furthermore, a pair of holding parts 5 and 6 on the upper side and lower side of each load measuring member 1 and the load detection part 4 are integrally formed, and a cross-sectional area of a cross section perpendicular to the axis of the load detection part 4 is obtained. Since the cross-sectional area of the cross section perpendicular to the axis of the load detection unit 4 of the upper side holding unit 5 and the contact member 2 and the lower side holding unit 6 and the support member 3 which are arranged in close contact with each other is greatly increased. The reflection / interference of the stress wave in the load detector 4 of the measuring member 1 can be promoted. As a result, it is possible to achieve early saturation of the stress wave in the load detection unit 4 related to the original load to be measured. As a result, the tensile load or the compressive load can be measured in a wide range of deformation speeds including high-speed deformation. It becomes possible to carry out with high precision.

In the above-described embodiment, the load measuring member 1 is composed of a total of 36 rows arranged in 6 rows in the horizontal direction and 6 rows in the vertical (depth direction) in plan view. The number of can be arbitrarily set as long as it is plural. For example, it is possible to adjust the total number of load measuring means arranged for various conditions such as the test scale and test contents, thereby eliminating the trouble of preparing and designing another load measuring device for each test.
In the above embodiment, the load measuring members 1 are arranged so that the upper and lower end surfaces formed by the upper and lower holding portions 5 and 6 are formed in a substantially square shape in plan view by the gathering of the total load measuring members 1. However, the arrangement of the load measuring members can be arbitrarily set according to various conditions such as the test scale and test contents.
Note that the number and arrangement of load measuring members are preferably set so that the load measuring members can be collectively arranged so that the load detectors are as dense as possible.

Further, in the above-described embodiment, the pair of holding portions 5 and 6 of each load measuring member 1 are formed in a substantially square cubic shape in plan view. However, the pair of holding portions are not necessarily in a square shape in plan view. It is not necessary to. The holding section can be integrated with the load detection section, and the cross-sectional area of the pair of holding sections perpendicular to the axis of the load detection section is greater than the cross-sectional area of the cross-section perpendicular to the axis of the load detection section. Can be formed into an arbitrary shape such as a substantially rectangular shape in a plan view, a substantially pentagonal shape, a substantially hexagonal shape, etc. In addition, the one holding part and the other holding part may have different shapes and different sizes.
However, in this case, it is preferable that the upper side and lower side holding portions of the adjacent load measuring members can be arranged in close contact with each other.

Moreover, in the said embodiment, the contact member 2 and the support member 3 are each made into plate shape (cubic shape) of planar shape substantially square shape, respectively, The plate surface is the upper side holding | maintenance part of all the said load measurement members 1 5 or the upper end surface or the lower end surface of the substantially square shape in plan view formed by the assembly of the lower side holding portions 6. However, in the contact member and the support member, the cross-sectional area of the cross section orthogonal to the axis of the load detection part of the load measuring member is larger than the cross-sectional area of the cross section orthogonal to the axis of each load detection part, and all the loads As long as it can be connected to the measurement member, the shape and size in plan view can be arbitrarily set.
Therefore, the load measuring member may protrude from the periphery of the contact member or the support member, and conversely, the peripheral portion of the contact member or support member protrudes from the upper and lower end surfaces of the holding portion formed by the set of load measuring members. It can be large.

In this embodiment, the contact member 2 and the support member 3 constituting the load measuring device, and each load measuring member 1 are all made of the same material, that is, having the same elastic modulus and density. However, the contact member, the support member, and each load measuring member may be formed of different materials. Here, when the materials of these members are different, it is necessary to consider not only the cross-sectional area but also the acoustic impedance when measuring the load. Since acoustic impedance is expressed by the product of material density and stress wave (= elastic wave) propagation velocity, it is important to consider the cross-sectional area multiplied by the density and stress wave propagation velocity when using different materials. .
In addition, about the material used for each member, it is preferable to use a material with a high Young's modulus.

In order to confirm the effect of the present invention, the load measuring device described in the above embodiment (hereinafter referred to as “example of the present invention”) and a conventional load measuring device as Comparative Example 1, that is, formed in a substantially square shape in plan view. A rectangular parallelepiped load formed between the contact member and the support member of the same shape and the same size and formed in a substantially square shape in plan view in which the cross-sectional area of the horizontal cross section is substantially the same as that of the contact member and the support member. As for Comparative Example 2, in addition to the same contact member and support member, a high-speed collision object was placed on each contact member with a cylindrical load detection unit having a diameter of 120 mm between them. A comparative analysis of performance due to collision was performed.
The collision object is spherical, has a weight of 2 kg, and the collision speed is 35 km / h.
The example of the present invention and the two comparative examples have a substantially square cross-sectional area of the horizontal cross section of the contact member and the support member, and the collision position of the collision object in both the present invention example and the comparative example, The corner portion on the plate surface of the contact member was used.
In the example of the present invention, as shown in FIG. 5, nine load measuring members are arranged in parallel between the contact member and the support member having a substantially square shape in plan view. The cross-sectional area of the load detecting section is equal to the sum of the cross-sectional areas of the plurality of load detecting sections of the present invention. The dimensions of each load measuring device are shown in FIG. 5 (note that the unit of dimensions in FIG. 5 is “mm”).

In this analysis, first, an unbalanced force when a collision object collides (in the case of the present invention, the cross-sectional force generated at the boundary between the load detection unit and the upper side holding unit and the boundary between the load detection unit and the lower side holding unit) In the case of the comparative example, the cross-sectional force generated at the boundary between the load detection unit and the contact member and the cross-sectional force generated at the boundary between the load detection unit and the support member were evaluated.
As a result, as shown in FIG. 6, the unbalance force in the example of the present invention is generally lower than that of the comparative example, and the device of the example of the present invention satisfies the balanced state instantly than the device of the comparative example. It was confirmed that it is excellent as a measuring device.
In FIG. 6, the horizontal axis represents the elapsed time after the collision, and the vertical axis represents the difference in cross-sectional force.

Furthermore, in the case of the present invention, plastic deformation did not occur in each load detection unit, but in the case of Comparative Example 2, the localization of the deformation progressed at the joint between the load detection unit and the contact member, and plastic deformation occurred. Was.
As described above, even when an eccentric load acts on the contact member and a large bending moment is generated in the load detecting portion in the past, the load measuring device of the present invention does not cause plastic deformation and has high accuracy. It was proved that the load measurement can be performed.

DESCRIPTION OF SYMBOLS 1 Load measuring member 2 Contact member 3 Support member 4 Load detection part 5 Upper side holding part 6 Lower side holding part As ₁ Cross sectional area of contact member As ₂ Cross sectional area of support member Ak Cross section area of load detecting part Ah ₁ Upper side holding Sectional area of the Ah ₂ sectional area of the lower side holding part

Claims (3)

A cylindrical load detection unit for measuring a tensile load or a compression load, and a pair of holding units provided at both ends in the axial direction of the load detection unit, and the pair of holding units and the load detection unit A plurality of load measuring members formed integrally and having a cross-sectional area of a cross section orthogonal to the axis of the load detection unit in the pair of holding units larger than a cross-sectional area of the cross section orthogonal to the axis of the load detection unit;
A single contact member for applying a tensile load or a compressive load, in which a holding portion on one side of each load measuring member is in close contact and connected by a bolt ,
A holding member on the other side of each load measuring member is in close contact with each other and connected by a bolt , and
Each load measuring member, contact member and support member are each made of a material having a Young's modulus equal to or higher than the Young's modulus of iron,
The plurality of load measurement members are arranged in parallel between the contact member and the support member so that the axial directions of the load detection units are parallel to each other,
The contact member and the support member are formed such that a cross-sectional area of a cross section orthogonal to the axis of the load detection unit of the load measuring member is larger than a cross-sectional area of a cross section orthogonal to the axis of each load detection unit,
The impact load measurement is characterized in that the holding part on one side and the holding part on the other side of each load measuring member are arranged in a state where the holding parts of the adjacent load measuring members are in close contact with each other. Load measuring device.   The load measuring device for measuring an impact load according to claim 1, wherein the holding portion has a polygonal prism shape in plan view. A cylindrical load detection unit for measuring a tensile load or a compression load, and a pair of holding units provided at both ends in the axial direction of the load detection unit, and the pair of holding units and the load detection unit A plurality of load measuring members formed integrally and having a cross-sectional area of a cross section orthogonal to the axis of the load detection unit in the pair of holding units larger than a cross-sectional area of the cross section orthogonal to the axis of the load detection unit;
A single contact member for applying a tensile load or a compressive load, in which a holding portion on one side of each load measuring member is in close contact and connected by a bolt ,
A holding member on the other side of each load measuring member is in close contact with each other and connected by a bolt , and
Each load measuring member, contact member and support member are each made of a material having a Young's modulus equal to or higher than the Young's modulus of iron,
The plurality of load measurement members are arranged in parallel between the contact member and the support member so that the axial directions of the load detection units are parallel to each other,
The contact member and the support member are formed such that a cross-sectional area of a cross section orthogonal to the axis of the load detection unit of the load measuring member is larger than a cross-sectional area of a cross section orthogonal to the axis of each load detection unit,
And using the load measuring device in which the holding part on one side and the holding part on the other side of each load measuring member are arranged in a state where the holding parts of the adjacent load measuring members are in close contact with each other. A method for measuring a collision load, characterized by measuring a collision load applied to a member.

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