JP4621060B2

JP4621060B2 - High-precision tensile or compression testing equipment over a wide range of strain rates including high-speed deformation

Info

Publication number: JP4621060B2
Application number: JP2005108182A
Authority: JP
Inventors: 朗弘上西; 博司吉田
Original assignee: Nippon Steel Corp
Current assignee: Nippon Steel Corp
Priority date: 2005-04-05
Filing date: 2005-04-05
Publication date: 2011-01-26
Anticipated expiration: 2025-04-05
Also published as: JP2006284517A

Description

本発明は、自動車構造を代表とする衝撃吸収部材の設計に必要な高速変形を含む広範囲のひずみ速度での引張又は圧縮荷重の計測装置に関する。 The present invention relates to a measuring device for tensile or compressive load in a wide range of strain rates including high-speed deformation necessary for designing an impact absorbing member typified by an automobile structure.

近年、自動車業界では、衝突時の乗員への傷害を低減しうる車体構造の開発が急務の課題となっている。この課題の解決のために、計算機上で自動車の衝突のシミュレーションを行い、安全基準をクリアする設計を行うシステムの開発が急速に進んできている。従って、現在ではこの衝突のシミュレーションの精度が衝撃吸収設計の成否のカギとなっている。衝突時には自動車の部材は高速で変形されるため、その正確な特性把握のためには、部材を構成する材料の高速の変形特性を精密に計測する必要がある。 In recent years, in the automobile industry, the development of a vehicle body structure that can reduce injury to passengers during a collision has become an urgent issue. In order to solve this problem, the development of a system that performs a simulation to meet safety standards by simulating a car collision on a computer is rapidly progressing. Therefore, at present, the accuracy of this collision simulation is the key to the success or failure of the shock absorption design. Since an automobile member is deformed at high speed at the time of a collision, it is necessary to accurately measure the high-speed deformation characteristics of the material constituting the member in order to accurately grasp the characteristics.

このような材料の高速変形特性の計測は、通常の準静的な引張または圧縮試験機では行うことが出来ず、特に荷重の計測方法が困難であった。この問題を克服するために、特許文献１に油圧サーボ試験機を用いるものが開示されているものの、従来型の簡便なロードセル（荷重検出装置）を用いるのではなく、変形特性を測定する試験片のつかみ部を延長してそこにひずみゲージを貼付し、このひずみゲージ出力から別に校正したロードセル出力／ゲージ出力比を用いて試験片の変形応力を計測する方法が知られている。これは従来型のロードセルを用いるのに比べて測定精度が向上するが、対象の試験片に毎回ひずみゲージを貼付しなければいけないこと、試験片毎に測定系が変化するため測定精度の維持が難しく、またその機構から精度の抜本的な向上が難しいことなどの問題があった。また油圧サーボ試験機はその構造上非常に高価である。 Such measurement of high-speed deformation characteristics of materials cannot be performed with a normal quasi-static tensile or compression tester, and the load measuring method is particularly difficult. In order to overcome this problem, although a technique using a hydraulic servo tester is disclosed in Patent Document 1, a test piece for measuring deformation characteristics instead of using a conventional simple load cell (load detection device). A method of measuring the deformation stress of a test piece using a load cell output / gauge output ratio separately calibrated from the strain gauge output is known. This improves the measurement accuracy compared to using a conventional load cell. However, the strain gauge must be attached to the target test piece every time, and the measurement system changes for each test piece. There is a problem that it is difficult, and it is difficult to drastically improve accuracy from the mechanism. The hydraulic servo tester is very expensive due to its structure.

また、特許文献２では、ブロック状の基部の上に突設した小突起部に、基部からの応力波の伝播および透過を遮断するための絶縁手段で構成される衝撃試験装置が開示されている。この装置では基部に比べて小さい小突起部で荷重の計測を行うが、この際、小突起部中を伝播する応力波の影響がなく、絶縁手段が基部と外部の応力波の伝播および透過を遮断することにより高ひずみ速度で計測が可能となることが示されている。しかしながら、一般に応力波の伝播を防ぐための絶縁手段の選択は難しく、その具体的な方法は開示されていない。 Further, Patent Document 2 discloses an impact test apparatus constituted by an insulating means for blocking the propagation and transmission of stress waves from a base portion on a small protrusion portion protruding on a block-like base portion. . In this device, the load is measured with a small protrusion smaller than the base, but at this time, there is no influence of the stress wave propagating through the small protrusion, and the insulating means transmits and transmits the stress wave between the base and the outside. It has been shown that measurement at a high strain rate is possible by blocking. However, it is generally difficult to select an insulating means for preventing the propagation of stress waves, and no specific method is disclosed.

また詳細は不明ながら近年新しい衝撃試験システムの装置が開示されている（非特許文献１）。これによると荷重検出部はつかみ部等を一体・軽量化することにより共振周波数を高めることにより高ひすみ速度での計測が可能であるとしているものの、開示されている図から判断すると試験片側から、つかみ部、荷重検出部という形で試験装置を配置することが記載されており、配置面からは従来型の装置と大きな差はない。 Further, a new impact test system device has been disclosed in recent years, although details are unknown (Non-Patent Document 1). According to this, although the load detection part says that it is possible to measure at a high stagnation speed by increasing the resonance frequency by making the grip part etc. integrated and lightweight, judging from the disclosed figure, from the test piece side It is described that the test apparatus is arranged in the form of a gripping part and a load detection part, and there is no significant difference from the conventional type in terms of arrangement.

一方、非特許文献２などにあるように、細長い弾性棒で衝撃弾性波を棒の長手方向に逃がすことにより、試験変形時の応力のみを計測すること可能にする、いわゆるＫｏｌｓｋｙ法が高速変形の試験法として標準的に使われている。しかしながら、試験装置が大掛かりであり、構造的に精度の維持管理が難しく、精度の高いデータを得るためには深い経験と知識が必要であった。また、試験可能時間が入射させた応力波パルスの継続時間、または、荷重を計測する弾性棒（ｔｒａｎｓｍｉｔｔｅｒｂａｒ）の長さにより制限されるため、延性の良い材料の計測には困難があった。
特開平１０−３１８８９４号公報特開平１０−３０９８０号公報島津高速衝撃試験システムパンフレットＣ２２５−３４５５ハイドロショットＨＩＴＳ−Ｔ１０ＳＡＥＴＥＣＨＮＩＣＡＬＰＡＰＥＲ＃９６００１９（１９９６年１０月発行、発行所：ＳｏｃｉｅｔｙｏｆＡｕｔｏｍｏｔｉｖｅＥｎｇｉｎｅｅｒ） On the other hand, as described in Non-Patent Document 2, etc., the so-called Kolsky method, which makes it possible to measure only the stress at the time of test deformation by letting a shock elastic wave escape in the longitudinal direction of the rod with an elongated elastic rod, is a high-speed deformation. It is used as a standard test method. However, the testing apparatus is large-scale, and it is structurally difficult to maintain and maintain accuracy, and deep experience and knowledge are required to obtain highly accurate data. Moreover, since the testable time is limited by the duration of the stress wave pulse that is incident or the length of the elastic bar that measures the load, it has been difficult to measure a material with good ductility.
JP-A-10-318894 Japanese Patent Laid-Open No. 10-30980 Shimadzu high-speed impact test system Pamphlet C225-3455 Hydroshot HITS-T10 SAE TECHNICICAL PAPER # 960019 (issued in October 1996, Publisher: Society of Automotive Engineer)

本発明は、衝突シミュレーションや衝突安全設計について評価基準となる材料の高速変形特性の測定において、精度の高い変形応力測定を簡便に行う装置を提供することを目的とする。 An object of the present invention is to provide an apparatus that can easily perform highly accurate deformation stress measurement in measurement of high-speed deformation characteristics of a material that is an evaluation standard for collision simulation and collision safety design.

本発明者らは、試験実行時の応力波の伝播特性に注目して検討を行い、測定したい荷重のできるだけ近くに荷重検出部を配置すること、試験片から荷重検出部、および荷重検出部を支持する支持機構につながる部分の断面積を適正に配置することにより、比較的簡便な手段で高ひずみ速度域までの高速変形特性が測定可能であることを見出した。本発明の要旨とするところは以下のとおりである。
（１）丸棒又は板状の試験片を固定する固定部を有する締結部と、引張荷重又は圧縮荷重を計測する荷重検出部と、前記締結部を固定支持する支持機構と、前記試験片に引張又は圧縮変形を与える可動部からなる装置において、前記締結部と前記荷重検出部を一体化し、前記荷重検出部は前記固定部より前記支持機構側に設置され、かつ
（前記固定部における前記締結部の断面積）≦（荷重検出部における前記締結部の断面積）＜（支持機構の断面積）
の条件を満たし、かつ、前記可動部が一端側に試験片が結合される弾性棒と、該弾性棒における試験片と反対側の端部を固定する変位負荷機構と、試験片と変位負荷機構との間の位置に配設された弾性棒固定機構とを有し、弾性棒固定機構によって固定された弾性棒を変位負荷機構によって変形させて弾性エネルギーを蓄えた後、弾性棒固定機構の固定を解除することにより応力波パルスを発生させて弾性棒を通じて試験片に伝播させる応力波パルス発生機構により構成されることを特徴とする高速引張又は高速圧縮荷重計測装置。
（２）前記締結部と弾性棒端の変位を計測し、その差から試験片の変位を計測する変位計測手段を有することを特徴とする（１）又は（２）に記載の高速引張又は高速圧縮荷重計測装置。
（３）締結部が円柱状であり、板状の試験片の場合には試験片を固定する溝を設置し、丸棒状の試験片の場合には試験片を固定するネジ穴が設置された締結部を持ち、前記荷重検出部における締結部の直径Ｄ（ｍｍ）と、前記溝またはネジ穴下端から支持機構上端までの長さＬ（ｍｍ）の比が０．３≦Ｌ／Ｄ≦１０を満たすことを特徴とする（１）〜（３）のいずれかに記載の高速引張又は高速圧縮荷重計測装置。
（４）前記荷重検出部における前記締結部の断面積Ａ０（ｍｍ ^２）と、前記支持機構の断面積Ａ１（ｍｍ ^２）との比が
２≦Ａ１／Ａ０
を満たすことを特徴とする（１）〜（４）のいずれかに記載の高速引張又は高速圧縮荷重計測装置。
（５）丸棒又は板状の試験片を固定する固定部を有する締結部と、引張荷重又は圧縮荷重を計測する荷重検出部と、前記締結部を支持する支持機構と、前記試験片に引張又は圧縮変形を与える可動部からなる装置において、前記締結部と前記荷重検出部を一体化し、前記荷重検出部は前記固定部より前記支持機構側に設置され、かつ
（前記固定部における前記締結部の断面積≦（荷重検出部における前記締結部の断面積）≦（支持機構の断面積）
の条件を満たし、かつ前記可動部が弾性棒を有する応力波パルス発生機構により構成されるとともに、前記荷重検出部における前記締結部の断面積をＡ０としたときに
２≦Ａ２／Ａ０
を満たす断面積Ａ２（ｍｍ ^２）を持つ応力波緩衝部を、前記締結部と前記支持機構の間に配置することを特徴とする高速引張又は高速圧縮荷重計測装置。
（６）前記可動部が、一端側に試験片が結合される弾性棒と、該弾性棒における試験片と反対側の端部を固定する変位負荷機構と、試験片と変位負荷機構との間の位置に配設された弾性棒固定機構とを有し、弾性棒固定機構によって固定された弾性棒を変位負荷機構によって変形させて弾性エネルギーを蓄えた後、弾性棒固定機構の固定を解除することにより応力波パルスを発生させて弾性棒を通じて試験片に伝播させる応力波パルス発生機構により構成されることを特徴とする（５）に記載の高速引張又は高速圧縮荷重計測装置。
（７）前記可動部が、一端側に試験片が結合される弾性棒と、該弾性棒に応力波パルスを発生させる中空又は中実の構造体と、上記該弾性棒における試験片と反対側の端部に一体化させた、構造体の受け止め機構とを有し、上記構造体を受け止め機構に向けて射出することにより弾性棒における上記構造体の受け止め機構側の端面に応力波パルスを発生させ、弾性棒を通じて試験片に伝播させる応力波パルス発生機構により構成されることを特徴とする（５）に記載の高速引張又は高速圧縮荷重計測装置。
（８）更に、試験片の温度を可変とする温度制御機構を備えることを特徴とする（１）〜（７）のいずれかに記載の高速引張又は高速圧縮荷重計測装置。 The inventors of the present invention have studied by paying attention to the propagation characteristics of stress waves at the time of test execution, placing the load detection unit as close as possible to the load to be measured, and separating the load detection unit and the load detection unit from the test piece. It has been found that high-speed deformation characteristics up to a high strain rate range can be measured by a relatively simple means by appropriately arranging the cross-sectional area of the portion connected to the supporting mechanism to be supported. The gist of the present invention is as follows.
(1) A fastening part having a fixing part for fixing a round bar or a plate-shaped test piece, a load detection part for measuring a tensile load or a compression load, a support mechanism for fixing and supporting the fastening part, and the test piece In an apparatus including a movable part that applies tensile or compressive deformation, the fastening part and the load detection part are integrated, and the load detection part is installed on the support mechanism side from the fixing part, and (the fastening in the fixing part is performed) Sectional area) ≦ (cross sectional area of the fastening portion in the load detection section) <(cross sectional area of the support mechanism)
And a movable load is connected to one end side of the elastic rod, and an elastic rod to which the end of the elastic rod opposite to the test piece is fixed, a test piece and a displacement load mechanism The elastic rod fixing mechanism is disposed between the elastic rod fixing mechanism and the elastic rod fixed by the elastic rod fixing mechanism is deformed by the displacement load mechanism to store elastic energy, and then the elastic rod fixing mechanism is fixed. A high-speed tensile or high-speed compressive load measuring device comprising a stress wave pulse generating mechanism for generating a stress wave pulse by releasing the wave and propagating it to a test piece through an elastic rod .
(2) It has a displacement measuring means for measuring the displacement of the fastening part and the end of the elastic rod, and measuring the displacement of the test piece from the difference between them. Compressive load measuring device.
(3) The fastening part is cylindrical, and in the case of a plate-shaped test piece, a groove for fixing the test piece is installed, and in the case of a round bar-shaped test piece, a screw hole for fixing the test piece is installed. The ratio of the diameter D (mm) of the fastening part in the load detection part to the length L (mm) from the groove or screw hole lower end to the upper end of the support mechanism is 0.3 ≦ L / D ≦ 10. The high-speed tensile or high-speed compression load measuring device according to any one of (1) to (3), wherein:
(4) The ratio of the cross-sectional area A0 (mm ² ) of the fastening portion in the load detection unit to the cross-sectional area A1 (mm ² ) of the support mechanism is
2 ≦ A1 / A0
The high-speed tensile or high-speed compression load measuring device according to any one of (1) to (4), wherein:
(5) A fastening portion having a fixing portion for fixing a round bar or a plate-shaped test piece, a load detection portion for measuring a tensile load or a compressive load, a support mechanism for supporting the fastening portion, and a tension on the test piece Alternatively, in an apparatus comprising a movable part that applies compressive deformation, the fastening part and the load detection part are integrated, and the load detection part is installed closer to the support mechanism than the fixed part, and
(Cross sectional area of the fastening portion in the fixed portion ≦ (Cross sectional area of the fastening portion in the load detecting portion) ≦ (Cross sectional area of the support mechanism)
And the movable part is constituted by a stress wave pulse generation mechanism having an elastic rod, and the cross-sectional area of the fastening part in the load detection part is A0
2 ≦ A2 / A0
A high-speed tensile or high-speed compressive load measuring device , wherein a stress wave buffer portion having a cross-sectional area A2 (mm ² ) satisfying the above condition is disposed between the fastening portion and the support mechanism .
(6) The movable part includes an elastic rod to which a test piece is coupled on one end side, a displacement load mechanism for fixing an end of the elastic bar opposite to the test piece, and between the test piece and the displacement load mechanism. The elastic rod fixing mechanism is disposed at the position of the elastic rod, and the elastic rod fixed by the elastic rod fixing mechanism is deformed by the displacement load mechanism to store elastic energy, and then the elastic rod fixing mechanism is released. The high-speed tension or high-speed compression load measuring device according to (5), characterized in that it is configured by a stress wave pulse generation mechanism that generates a stress wave pulse and propagates it to a test piece through an elastic rod .
(7) The movable portion includes an elastic rod having a test piece coupled to one end thereof, a hollow or solid structure that generates a stress wave pulse on the elastic rod, and the opposite side of the elastic rod from the test piece. And a structure receiving mechanism integrated with the end of the structure, and by emitting the structure toward the receiving mechanism, a stress wave pulse is generated on the end surface of the elastic structure on the receiving mechanism side of the structure. The high-speed tensile or high-speed compression load measuring device according to (5), wherein the high-speed tensile or high-speed load measuring device is configured by a stress wave pulse generation mechanism that propagates to a test piece through an elastic rod .
(8) The high-speed tension or high-speed compression load measuring device according to any one of (1) to (7), further comprising a temperature control mechanism that makes the temperature of the test piece variable.

本発明に基づいて高精度な材料の高速変形特性を計測し、更に、この特性を導入することによる高精度な衝突シミュレーションを行うことにより、従来行われていた自動車全体設計または部材設計時に衝突安全性を確保するための試作部材による試行錯誤を省略することができ、試作のためのコストを大幅に軽減するだけでなく、設計にかかる時間も短縮することができる。従来の試験方法に比べて、必要な時間、コストを大幅に低減することができる。 By measuring the high-speed deformation characteristics of high-precision materials based on the present invention, and by performing high-precision collision simulation by introducing these characteristics, it is possible to perform collision safety at the time of designing the entire automobile or parts that has been performed conventionally. Trial and error by the prototype member for ensuring the performance can be omitted, and not only the cost for the prototype can be greatly reduced, but also the design time can be shortened. Compared with the conventional test method, the required time and cost can be greatly reduced.

本発明者らは、まずこれまでの高速変形の試験方法を鋭意検討した。その結果、高精度の試験結果が得られるＫｏｌｓｋｙ法と、簡便であるが精度の劣る油圧サーボ方式との違いの一つは荷重計測の位置にあることに思い至った。 First, the present inventors diligently studied the conventional high-speed deformation testing method. As a result, it came to mind that one of the differences between the Kolsky method, which provides highly accurate test results, and the hydraulic servo method, which is simple but inaccurate, is in the position of load measurement.

これを解消するにはまず試験片の近くで荷重計測を行う必要がある．しかしながら、特許文献１に開示されているように、試験片に直接ひずみゲージを貼り付けた場合には、応力集中を考慮した荷重の補正が必要であり、それぞれの試験片に対してひずみゲージを貼付する必要があり精度管理が難しいこと、さらにそれぞれの試験片にひずみゲージを貼付する必要があるため試験のコストが高いという欠点があった。 To solve this problem, it is necessary to measure the load near the specimen. However, as disclosed in Patent Document 1, when a strain gauge is directly attached to a test piece, it is necessary to correct the load in consideration of stress concentration, and a strain gauge is attached to each test piece. There are disadvantages that it is difficult to control the accuracy because it is necessary to affix, and that a strain gauge needs to be affixed to each test piece.

また、特許文献２に開示される方法においても、荷重計測を試験片近くで行っているが、荷重計測用小突起部の内部での応力波伝播の影響を受けないようにするためには、その大きさを制限する必要があり、従って計測できる荷重に限界が生じてしまう。また、この方法ではブロック状の基部と外部との間に何らかの絶縁手段が必要であった。 Also, in the method disclosed in Patent Document 2, load measurement is performed near the test piece, but in order not to be affected by stress wave propagation inside the small protrusion for load measurement, It is necessary to limit the size thereof, and thus a limit is imposed on the load that can be measured. In addition, this method requires some insulating means between the block-shaped base and the outside.

本発明者らがさらに検討を進めた結果、試験片から荷重検出部の間の断面積変化が計測精度に大きく影響することが分かってきた。通常の油圧サーボ式高速引張試験機では試験片を装置に固定するために比較的断面積の大きな固定部を有する締結部があり、さらに支持機構を介して、荷重検出部につながっていた。このとき各部の断面積変化は通例、（試験片）＜（締結部）、（締結部）＞（支持機構）、（支持機構）＜（荷重検出部）のようになっていた。このような配置での実験を繰り返したところ、断面積が大の領域から小の領域に進行する場合には応力波の伝播の乱れが非常に大きいが、小から大の領域に進行する場合、小の領域ではその乱れの影響をほとんど受けないということが判明した。 As a result of further studies by the present inventors, it has been found that a change in the cross-sectional area between the test piece and the load detection unit greatly affects the measurement accuracy. In a normal hydraulic servo type high-speed tensile testing machine, there is a fastening part having a fixing part having a relatively large cross-sectional area in order to fix the test piece to the apparatus, and further connected to the load detection part via a support mechanism. At this time, the change in the cross-sectional area of each part is usually (test piece) <(fastening part), (fastening part)> (support mechanism), (support mechanism) <(load detection part). When the experiment with such an arrangement was repeated, when the cross-sectional area proceeds from a large region to a small region, the disturbance of stress wave propagation is very large, but when the cross-sectional area proceeds from a small region to a large region, It turns out that the small area is hardly affected by the disturbance.

この事実に基づき、図４に模式図を示すように、本発明者らは試験片締結部と荷重検出部２とを一体化した。その理由は締結部と荷重検出部２との固定が十分でないとその界面で応力波の大きな反射が起こるために、荷重検出部２での計測値に振動が重畳してしまうことを避けるためである。この一体化は削り出し加工により行うことが望ましいが、必要に応じてネジ締結、ボルト締結、溶接等の方法が使用できる。この際、締結による断面積変化を極力小さく必要がある。さらに、断面積の変化が荷重検出部に至るまでに大から小となることがないように、（試験片の断面積）＜（試験片と締結部との固定部１１における締結部の断面積）≦（荷重検出部２における締結部の断面積）≦（支持機構３の断面積）と配置することで、１)締結部を小さくかつ支持機構を介さず荷重検出部につなぎ、試験片の近くで荷重計測を行う、２)応力波の反射や干渉による乱れの影響を小さくする、ことを思い至った。 Based on this fact, as shown in a schematic diagram in FIG. 4, the present inventors integrated the test piece fastening portion and the load detection portion 2. The reason is that if the fastening part and the load detection part 2 are not sufficiently fixed, a large reflection of the stress wave occurs at the interface, so that the vibration is not superimposed on the measurement value at the load detection part 2. is there. Although this integration is preferably performed by machining, methods such as screw fastening, bolt fastening, and welding can be used as necessary. At this time, it is necessary to minimize the cross-sectional area change due to fastening. Further, the cross-sectional area of the fastening portion in the fixing portion 11 of the test piece and the fastening portion is not so large that the change in the cross-sectional area does not become large to small before reaching the load detecting portion. ) ≦ (Cross sectional area of the fastening part in the load detection part 2) ≦ (Cross sectional area of the support mechanism 3) 1) The fastening part is small and connected to the load detection part without the support mechanism. I came up with the idea of measuring the load nearby, and 2) reducing the effects of turbulence caused by stress wave reflection and interference.

通常の変形速度で試験を行う場合は試験速度に比べて試験片および試験機内を伝播する応力波の伝播速度は十分に大きいため、直列につながる試験機のどの断面で荷重を測定してもその値は一定となる。しかし今問題にしている高ひずみ速度変形では、応力波の伝播速度が十分大きいとは言えず、応力波の伝播を考慮しなければ正確な荷重計測はできない。通常のロードセルで荷重計測を行うと正規の波形に重畳して振動が観測されるがこれは試験機内を伝播する応力波の影響である。 When testing at normal deformation speed, the propagation speed of the stress wave propagating through the test piece and the test machine is sufficiently large compared to the test speed, so no matter which section of the test machine connected in series, the load is measured The value is constant. However, in the high strain rate deformation that is now a problem, it cannot be said that the propagation speed of the stress wave is sufficiently high, and accurate load measurement cannot be performed without considering the propagation of the stress wave. When load measurement is performed with a normal load cell, vibration is observed superimposed on the normal waveform, but this is due to the influence of the stress wave propagating in the testing machine.

上述のように試験を行った場合、まず応力波は試験片内部で反射・干渉し、試験片内部の変形を均一化する。さらに締結部での同様の過程を経た後に、荷重検出部に応力波が伝播する。高ひずみ速度での高精度な荷重計測を行うためには、応力波ノイズの原因となる内部での反射・干渉を早期に飽和させることが必要である。応力波の反射は荷重検出部の支持機構との境界で起こるが、早期の飽和のためには支持機構の断面積が、荷重検出部の断面積と等しいか大きい必要がある。またさらに荷重検出部の軸方向長さを短くする必要がある。これは応力波が荷重検出部全体を伝播するのに必要な時間を低減するためである。 When the test is performed as described above, first, the stress wave is reflected and interfered inside the test piece to make the deformation inside the test piece uniform. Furthermore, after going through the same process at the fastening portion, the stress wave propagates to the load detection portion. In order to perform highly accurate load measurement at a high strain rate, it is necessary to quickly saturate internal reflection and interference that cause stress wave noise. The reflection of the stress wave occurs at the boundary with the support mechanism of the load detection unit. For early saturation, the cross-sectional area of the support mechanism needs to be equal to or larger than the cross-sectional area of the load detection unit. Furthermore, it is necessary to shorten the axial length of the load detection unit. This is to reduce the time required for the stress wave to propagate through the entire load detector.

荷重計測についてはこのような形で精度の高い計測が可能となることが判明したが、次に問題となるのは試験片を高ひずみ速度で変形させる手段、すなわち応力波パルス発生機構である。特許文献１や２に示されているように通常油圧サーボ機構が使用されるが、この方式は装置が大掛りであり通常高価である。そこで本発明では、非特許文献２で使用されているような弾性棒を用いて高ひずみ速度変形を与える方法を組み合せた。本発明では高ひずみ速度変形を弾性棒で与えるとともに、弾性棒中を伝わる応力波を計測することにより試験片と弾性棒の結合端面の変位を計算し、それを基に試験片のひずみを計測させる機能を兼ね合わせた。すなわち、棒が十分細い場合、棒中を応力波が一次元の縦波として伝播するが、この時試験片と弾性棒の境界Ａ端面の変位（ｕ_Ａ）は、境界Ａでの棒のひずみ（ε_Ａ）を用いて下記（１）式により計算できる。 With regard to load measurement, it has been found that high-precision measurement is possible in such a form, but the next problem is a means for deforming a test piece at a high strain rate, that is, a stress wave pulse generation mechanism. Normally, a hydraulic servomechanism is used as disclosed in Patent Documents 1 and 2, but this method requires a large apparatus and is usually expensive. Therefore, in the present invention, a method of applying a high strain rate deformation using an elastic rod as used in Non-Patent Document 2 is combined. In the present invention, high strain rate deformation is given by an elastic rod, and the displacement of the joint end surface of the test piece and the elastic rod is calculated by measuring the stress wave transmitted through the elastic rod, and the strain of the test piece is measured based on the displacement. Combined with the function to make. That is, when the bar is sufficiently thin, the stress wave propagates in the bar as a one-dimensional longitudinal wave. At this time, the displacement (u _A ) of the boundary A end surface between the specimen and the elastic bar is the strain of the bar at the boundary A. It can be calculated by the following equation (1) using (ε _A ).

さらにε_Ａは縦波伝播の時間遅れを利用して、境界Ａから離れた位置でのひずみとして計測できる。具体的には図１に示すように変位検出用ひずみゲージ５にて、その位置での弾性棒のひずみの時間変化を計測し、境界Ａから変位検出用ひずみゲージ５の距離を弾性棒中の弾性波速度で割った時間遅れを補正して求めることができる．このとき試験片のひずみε（ｔ）は荷重検出部側の試験片端面の変位（ｕ_Ｂ）も用いて、（２）式により求めることができる。

Furthermore, ε _A can be measured as a strain at a position away from the boundary A by utilizing the time delay of longitudinal wave propagation. Specifically, as shown in FIG. 1, a displacement detection strain gauge 5 measures the time variation of the strain of the elastic rod at that position, and the distance from the boundary A to the displacement detection strain gauge 5 is measured in the elastic rod. It can be obtained by correcting the time delay divided by the elastic wave velocity. At this time, the strain ε (t) of the test piece can be obtained by the equation (2) using the displacement (u _B ) of the end face of the test piece on the load detection unit side.

ここにＬ_０は試験片のゲージ長さ（ｍｍ）である。

Here, L ₀ is the gauge length (mm) of the test piece.

このような計測を可能とするためには弾性棒は全長に比して十分細い必要があり、ステンレス鋼を用いる場合にはその直径は３０ｍｍ以下、望ましくは２０ｍｍ以下であることが望ましい。 In order to enable such measurement, the elastic rod needs to be sufficiently thin compared to the entire length, and when stainless steel is used, its diameter is desirably 30 mm or less, desirably 20 mm or less.

前記（１）及び（６）に係る本発明では、応力波パルス発生機構が図２に示すように弾性棒４、弾性棒固定機構７、及び変位負荷機構８から構成されている。試験時にはまず弾性棒固定機構７の位置で弾性棒４の変位を固定する。その後、変位負荷機構８により弾性棒４を引張る。これにより弾性棒４の内、弾性棒固定機構７および変位負荷機構８に挟まれた部分が弾性的に変位し、弾性エネルギーが蓄えられる。試験片に対して所定のひずみ速度が与えられるよう変位負荷機構８を用いて弾性棒４を変形させた後に、弾性棒固定機構７を急激に解放することにより応力波パルスが発生し、弾性棒４を伝わって試験片を変形させるものである。 In the present invention according to the above (1) and (6) , the stress wave pulse generating mechanism is composed of the elastic bar 4, the elastic bar fixing mechanism 7, and the displacement load mechanism 8 as shown in FIG. During the test, first, the displacement of the elastic bar 4 is fixed at the position of the elastic bar fixing mechanism 7. Thereafter, the elastic rod 4 is pulled by the displacement load mechanism 8. As a result, a portion of the elastic rod 4 sandwiched between the elastic rod fixing mechanism 7 and the displacement load mechanism 8 is elastically displaced, and elastic energy is stored. After the elastic rod 4 is deformed by using the displacement load mechanism 8 so that a predetermined strain rate is given to the test piece, the elastic rod fixing mechanism 7 is suddenly released to generate a stress wave pulse. 4 is used to deform the test piece.

前記（７）に係る本発明では、応力波パルス発生機構が、図３に示すように、弾性棒４、中空構造体９及び弾性棒端に一体化させた中空構造体の受け止め機構１０により構成されている。試験時には中空構造体９を中空構造体の受け止め機構１０に向けて射出させることにより弾性棒４の端面に応力波パルスが発生し、弾性棒４を伝わって試験片を変形させるものである。図３では引張の際の配置が示されているが、中空構造体９を中空構造体の受け止め機構１０を介して弾性棒と反対側に設置して射出することにより圧縮試験を行うことができる。引張と圧縮を共用する場合には９は中空構造体である必要があるが、圧縮のみの場合は中実構造を用いることができる。弾性棒４への接触を均一とするためには圧縮の場合は中実構造とすることが望ましい。 In the present invention according to the above (7) , the stress wave pulse generation mechanism is constituted by the elastic rod 4, the hollow structure 9, and the hollow structure receiving mechanism 10 integrated with the elastic rod end as shown in FIG. Has been. During the test, the hollow structure 9 is injected toward the receiving mechanism 10 of the hollow structure to generate a stress wave pulse on the end face of the elastic bar 4, and the test piece is deformed along the elastic bar 4. Although FIG. 3 shows an arrangement during tension, a compression test can be performed by injecting and injecting the hollow structure 9 on the opposite side of the elastic rod through the hollow structure receiving mechanism 10. . In the case of sharing tension and compression, 9 needs to be a hollow structure, but in the case of compression only, a solid structure can be used. In order to make the contact with the elastic rod 4 uniform, a solid structure is desirable in the case of compression.

前記（２）に係る本発明では、試験片の変位、ひずみを計測する手段として、締結部と弾性棒端の変位を計測し、その差から求める変位計測手段を規定としている。具体的には簡便的に変位検出用ひずみゲージ５を用いる手段、変位検出用ひずみゲージ５と変位計測手段６を併用する手段、変位計測手段で一度に両端あるいは試験片のゲージ長さの時間変化を計測する手段、等を用いることができる。以下、それぞれについて詳しく説明する。
前述のように弾性棒端の変位は、変位検出用ひずみゲージ５の出力を時間遅れを考慮して端面Ａでのひずみに変換したものから、更に前述の（１）式を用いて計算できる。締結部側端面は本発明ではほとんど変位せず、実験誤差から考えると無視して差し支えない。その場合は（３）式に従い、端面Ａの変位ｕ_Ａを、試験片のゲージ長さで除して試験片のひずみε（ｔ）を求めることができる。 In the present invention according to the above (2) , as a means for measuring the displacement and strain of the test piece, the displacement measuring means for measuring the displacement of the fastening portion and the elastic rod end and obtaining the difference is defined. Specifically, means for simply using the strain gauge 5 for detecting displacement, means for using the strain gauge 5 for detecting displacement together with the displacement measuring means 6, and time variation of the gauge length of both ends or the test piece at once by the displacement measuring means. It is possible to use a means for measuring Each will be described in detail below.
As described above, the displacement of the elastic rod end can be calculated by using the above-described equation (1) from the output of the displacement detecting strain gauge 5 converted into the strain at the end face A in consideration of the time delay. The fastening part side end face is hardly displaced in the present invention, and can be ignored in view of experimental errors. In that case, the strain ε (t) of the test piece can be obtained by dividing the displacement u _A of the end face A by the gauge length of the test piece according to the equation (3).

また、試験片の全伸びが非常に小さい等で、ひずみの計測を精度高く行う必要がある場合には、締結部側の端面Ｂの変位ｕ_Ｂをレーザー式等の非接触の変位計のような変位計測手段６により計測しても良い。変位計測装置６の設置位置を図１中に示す。この場合、端面Ａの変位は変位検出用ひずみゲージ５の出力から求め、（２）式を用いて試験片のひずみε（ｔ）求める。

In addition, when the total elongation of the test piece is very small or the like and it is necessary to measure the strain with high accuracy, the displacement u _B of the end surface B on the fastening portion side is expressed as a non-contact displacement meter such as a laser type. It may be measured by a simple displacement measuring means 6. The installation position of the displacement measuring device 6 is shown in FIG. In this case, the displacement of the end face A is obtained from the output of the displacement detecting strain gauge 5, and the strain ε (t) of the test piece is obtained using the equation (2).

また、変位計測手段のみを用いて変位を直接測定しても良い。例えば試験片上にマーキングを行い、その画像処理により変位を求めることや、二眼式の光学式変位計を用いて両端の変位を同時に計測すること等の方法も、本発明に相応しい試験片の変位の計測方法である。このような変位計測手段は図１の変位計測手段６の位置に設置すればよい。 Further, the displacement may be directly measured using only the displacement measuring means. For example, the method of marking on a test piece and obtaining the displacement by image processing, or simultaneously measuring the displacement at both ends using a two-lens optical displacement meter is also suitable for the present invention. This is a measurement method. Such a displacement measuring means may be installed at the position of the displacement measuring means 6 in FIG.

前記（３）に係る本発明では、締結部が円柱状であり、締結部には試験片を固定する溝が設置され、試験片を固定するために、締結部に設置された溝の下端から支持機構の上端までの長さＬ（ｍｍ）と、荷重検出部における締結部の直径Ｄ（ｍｍ）の比Ｌ／Ｄの範囲が０．３以上１０以下であることが好適である In this invention which concerns on said (3) , the fastening part is cylindrical shape, the groove | channel which fixes a test piece is installed in a fastening part, and in order to fix a test piece, from the lower end of the groove | channel installed in the fastening part It is preferable that the range of the ratio L / D of the length L (mm) to the upper end of the support mechanism and the diameter D (mm) of the fastening part in the load detection part is 0.3 or more and 10 or less.

荷重検出部は表面に貼付したひずみゲージにより荷重を計測するために、断面内の荷重分布が均一である必要があるため円柱状である必要がある。一方締結部は必ずしも円柱状である必要はないが、荷重検出部と一体化し締結部での応力波の反射を少なくするためには円柱状であることが好ましい。また試験片の締結部は可能な限り小さくする必要がある。そのため本発明では板状の試験片の場合には締結部に溝を設け、そこに試験片を差込みピンで締結する方法をとっており、一方丸棒状の試験片ではネジ穴を設け、そこにネジを切った試験片を締結することにより試験片を固定している。 Since the load detection unit needs to have a uniform load distribution in the cross section in order to measure the load with a strain gauge attached to the surface, the load detection unit needs to be cylindrical. On the other hand, the fastening portion is not necessarily cylindrical, but is preferably cylindrical in order to integrate with the load detection portion and reduce reflection of stress waves at the fastening portion. Moreover, it is necessary to make the fastening part of a test piece as small as possible. Therefore, in the present invention, in the case of a plate-shaped test piece, a groove is provided in the fastening portion, and a method is adopted in which the test piece is inserted and fastened with an insertion pin, while a round bar-shaped test piece is provided with a screw hole, The test piece is fixed by fastening the threaded test piece.

比Ｌ／Ｄが０．３より小さくなると荷重検出部の応力が断面内で不均一となりひずみゲージにより測定した表面ひずみから算出した荷重と実際の荷重の差が大きくなる。また、１０超となると上記で説明したように、荷重検出部内部での応力波の飽和が起こりにくくなるので、上記の範囲とすることが好ましい。 When the ratio L / D is smaller than 0.3, the stress of the load detecting portion is not uniform in the cross section, and the difference between the load calculated from the surface strain measured by the strain gauge and the actual load is increased. Further, if it exceeds 10, as described above, stress waves are less likely to be saturated inside the load detection unit, and therefore, the above range is preferable.

前記（４）に係る本発明では、締結部が円柱状であり、締結部は試験片を固定する溝が設置され、支持機構の断面積Ａ１（ｍｍ^２）と、締結部の断面積Ａ０（ｍｍ^２）の比Ａ１／Ａ０が２以上であることが好適である。Ａ１／Ａ０が２未満であると、荷重検出部と支持機構との間での応力波の反射が起こりにくくなり、荷重検出部内部での応力波の飽和が遅くなるので、上記の範囲とすることが好ましい。 In this invention which concerns on said (4) , the fastening part is a column shape, the groove | channel which fixes a test piece is installed in a fastening part, cross-sectional area A1 (mm < ² >) of a support mechanism, and cross-sectional area A0 ( It is preferable that the ratio A1 / A0 of mm ² ) is 2 or more. When A1 / A0 is less than 2, stress waves are less likely to be reflected between the load detection unit and the support mechanism, and stress wave saturation within the load detection unit is delayed, so the above range is set. It is preferable.

しかしながら、実際の試験では試験機の動力機構や試験片の大きさ、強度に応じて前記（３）の条件を満足することが難しい場合がある。本発明者らはこのような場合についても鋭意検討し、締結部（荷重検出部）と支持機構の間に断面積Ａ２を持つ応力波緩衝部を、２≦Ａ２／Ａ０を満たすように配置すれば良いことを知見した（前記（５）に係る発明）。
また、応力緩衝部を持つ荷重検出装置はＡ１／Ａ０が２以上の場合に使用しても全く問題がなく、目的に応じて選択すればよい。また応力波緩衝部の軸方向長さＬ２については特に大きな制限はないが、締結部の溝下端から応力波緩衝部の上端までの長さＬ以上であることが好ましい。 However, in an actual test, it may be difficult to satisfy the condition (3) according to the power mechanism of the testing machine, the size and strength of the test piece. The inventors of the present invention have also studied earnestly in such a case, and arrange a stress wave buffer portion having a cross-sectional area A2 between the fastening portion (load detection portion) and the support mechanism so as to satisfy 2 ≦ A2 / A0. It has been found that (invention according to (5) above).
Further, the load detecting device having the stress buffering portion has no problem even if it is used when A1 / A0 is 2 or more, and may be selected according to the purpose. The axial length L2 of the stress wave buffer portion is not particularly limited, but is preferably not less than the length L from the lower end of the fastening portion to the upper end of the stress wave buffer portion.

以上の記述は試験機を構成する各部が同等材質、すなわち弾性率および密度が同程度であることを前提に記述してきたが、各部の材料が異なる場合には断面積だけではなく、音響インピーダンスをあわせて考慮する必要がある。音響インピーダンスは材料の密度と応力波（＝弾性波）伝播速度の積であらわされる。従って異種の材料を用いる場合には断面積に関する記述を（断面積）×（密度）×（応力波伝播速度）の値に置換することで本発明を利用することができる。 The above description is based on the premise that each part of the testing machine is of the same material, that is, the modulus of elasticity and density are the same, but if the material of each part is different, not only the cross-sectional area but also the acoustic impedance It is necessary to consider together. The acoustic impedance is expressed by the product of the material density and the stress wave (= elastic wave) propagation velocity. Therefore, when different types of materials are used, the present invention can be used by replacing the description of the cross-sectional area with the value of (cross-sectional area) × (density) × (stress wave propagation velocity).

また、このような荷重検出部は試験機の固定側に配置するのが望ましい。これは可動部に配置すると荷重負荷の揺動の影響を受けてしまうためである。
締結部の溝下端から応力波緩衝部の上端までの長さＬはひずみ速度１０００／ｓの領域では３０ｍｍ以下、望ましくは２０ｍｍ以下とするのが好ましい。これは応力波の伝播に対してＬとＤとの比だけでなく、応力波の伝播速度に対するＬの長さの絶対値が問題となるからである。 Moreover, it is desirable to arrange such a load detection unit on the fixed side of the testing machine. This is because if it is arranged on the movable part, it is affected by the swing of the load.
The length L from the groove lower end of the fastening portion to the upper end of the stress wave buffering portion is 30 mm or less, preferably 20 mm or less in the region of the strain rate of 1000 / s. This is because not only the ratio of L and D with respect to the propagation of the stress wave, but also the absolute value of the length of L with respect to the propagation speed of the stress wave becomes a problem.

以下に実例を挙げながら、本発明の技術内容について説明する。図１に本発明の装置の模式図を示す。また、応力波パルス発生機構としては図２のものを用いた。弾性棒は直径１６ｍｍで全長５ｍのステンレス棒鋼を用いた。弾性棒固定機構７は試験片側から２ｍの位置に設置した。従って、試験片を変形させるために使用される弾性棒固定機構７と変位負荷機構８との間の弾性棒の長さは３ｍとなる。変位負荷機構８としては空気圧シリンダーを用いた。このシリンダーに与える空気圧を変化させることにより弾性棒４の３ｍの部分（弾性棒固定機構と変位負荷機構に挟まれた部分）に与える弾性ひずみを変化させ、それにより試験片のひずみ速度を変更することができる。今回の試験は試験片のひずみ速度を約６００／ｓｅｃに相当する条件で行った。また図４に本発明例として用いた荷重検出装置の模式図を示す。試験片１としては板状のものを用い、試験片のチャック部に穴を開け、それを荷重検出装置の固定部１１の溝１２に差し込んだ後にピン（図示しない）を用いて締結した。試験片１は変形部の平行部長さ１０ｍｍ、幅５ｍｍのものを使用した。 The technical contents of the present invention will be described below with examples. FIG. 1 shows a schematic diagram of the apparatus of the present invention. The stress wave pulse generation mechanism shown in FIG. 2 was used. A stainless steel bar having a diameter of 16 mm and a total length of 5 m was used as the elastic bar. The elastic rod fixing mechanism 7 was installed at a position 2 m from the test piece side. Therefore, the length of the elastic bar between the elastic bar fixing mechanism 7 and the displacement load mechanism 8 used for deforming the test piece is 3 m. A pneumatic cylinder was used as the displacement load mechanism 8. By changing the air pressure applied to this cylinder, the elastic strain applied to the 3 m portion of the elastic rod 4 (the portion sandwiched between the elastic rod fixing mechanism and the displacement load mechanism) is changed, thereby changing the strain rate of the specimen. be able to. This test was performed under the condition corresponding to a strain rate of about 600 / sec. FIG. 4 shows a schematic diagram of a load detection device used as an example of the present invention. As the test piece 1, a plate-like one was used, a hole was made in the chuck part of the test piece, and the hole was inserted into the groove 12 of the fixing part 11 of the load detection device and then fastened using a pin (not shown). As the test piece 1, a deformed portion having a parallel portion length of 10 mm and a width of 5 mm was used.

表１に測定を行った条件とその結果を示す。図６にＮｏ．４の条件で試験を行った結果を示す。試験温度は室温である。また同時に比較例として同じ試験片を用いて通常の油圧サーボ式試験機で従来型ロードセルを用いて測定した。その模式図を図５に示す。結果は図６に同時に示してある。従来型ロードセルの値が応力波ノイズを含んで不正確な値となっているのに対して、本発明のロードセルでは高精度な計測が可能であった。 Table 1 shows the measurement conditions and the results. In FIG. The result of having performed the test on condition 4 is shown. The test temperature is room temperature. At the same time, the same test piece was used as a comparative example, and measurement was performed using a conventional load cell with a normal hydraulic servo tester. The schematic diagram is shown in FIG. The results are shown simultaneously in FIG. Whereas the value of the conventional load cell is an inaccurate value including stress wave noise, the load cell of the present invention can measure with high accuracy.

本検討ではさらに荷重検出装置の寸法の影響を把握するため、支持機構３を同一のものを用い、種々の応力検出装置を用いて試験を行った。Ｎｏ．１０に示すように荷重検出部２の直径Ｄと長さＬの比が１０を越え、前記（３）記載本発明の上限を越える場合には、測定時間内での荷重検出部の応力波の飽和が十分ではなく、測定波形に若干の応力波ノイズが見られたが、図５の比較例と比べると、十分に高精度な計測が可能であった。またＮｏ．１のようにＬ／Ｄが０．２５で前記（３）記載本発明の下限を下回る場合、応力波ノイズの問題はないものの、測定しようとする荷重が小さい場合に荷重検出部２の断面内で弾性変形が一様でなく、低荷重での測定荷重が実際の荷重よりもやや小さな値となったが、図６の比較例と比べると、十分に高精度な計測が可能であった。 In this study, in order to further understand the influence of the dimensions of the load detection device, the same support mechanism 3 was used and tests were performed using various stress detection devices. No. 10, when the ratio of the diameter D and the length L of the load detection unit 2 exceeds 10 and exceeds the upper limit of the present invention described in (3) above, the stress wave of the load detection unit within the measurement time Saturation was not sufficient, and some stress wave noise was observed in the measurement waveform, but sufficiently high-precision measurement was possible compared to the comparative example of FIG. No. When L / D is 0.25 and is below the lower limit of the present invention described in (3) , there is no problem of stress wave noise. However, when the load to be measured is small, However, the elastic deformation was not uniform, and the measured load at a low load was slightly smaller than the actual load, but sufficiently high-precision measurement was possible as compared with the comparative example of FIG.

また荷重検出部２の直径が比較的大であるＮｏ．１１、１２、１３では応力波ノイズの影響はほとんど見られないものの、荷重検出部２の弾性ひずみが小さくなるため、外来ノイズ（主に電源等から混入する電磁波ノイズ）の影響が大きくなった。荷重検出部２の直径は測定しようとする試験に生ずる最大荷重を勘案してできるだけ小さくする方が良い。具体的には試験片の最大荷重が、荷重検出部の円柱部分の弾性限界荷重の５０％以上１００％以下となるように直径Ｄを決めることが望ましい。また、前記（４）記載本発明の範囲にない、支持機構３と荷重検出部２の断面積の比（Ａ１／Ａ０）が１．４であるＮｏ．１４の場合、支持機構３と荷重検出部２との間で応力波の反射が効率よく行われず、従って荷重検出部２での応力波の飽和が遅くなり、測定波形に若干の応力波ノイズが生じた。その他の条件では良好な測定を行うことが出来た。 In addition, No. 2 in which the diameter of the load detection unit 2 is relatively large. 11, 12, and 13 show almost no influence of stress wave noise, but since the elastic strain of the load detection unit 2 becomes small, the influence of external noise (mainly electromagnetic wave noise mixed from a power source or the like) becomes large. The diameter of the load detector 2 should be as small as possible in consideration of the maximum load generated in the test to be measured. Specifically, it is desirable to determine the diameter D so that the maximum load of the test piece is 50% or more and 100% or less of the elastic limit load of the cylindrical portion of the load detection unit. Moreover, the ratio (A1 / A0) of the cross-sectional area of the support mechanism 3 and the load detection part 2 which is not in the scope of the present invention described in (4 ) is 1.4. 14, the stress wave is not efficiently reflected between the support mechanism 3 and the load detection unit 2, so that the stress wave saturation at the load detection unit 2 is delayed, and some stress wave noise is present in the measurement waveform. occured. Good measurement was possible under other conditions.

またＮｏ．５は図１に示す温度可変機構１４を設置して試験を行った場合である。Ｎｏ．５の試験では液体窒素を満たした小型の容器を温度可変機構として用いて、試験片の平行部と固定部１１の一部のみを覆った後、試験を行ったものである。温度可変機構を備える場合にも本発明の試験装置は良好な測定結果を得ることが出来た。 No. Reference numeral 5 denotes a case where the test was performed by installing the temperature variable mechanism 14 shown in FIG. No. In the test No. 5, a small container filled with liquid nitrogen was used as a temperature variable mechanism, and the test was performed after covering only the parallel part of the test piece and a part of the fixed part 11. Even when the temperature variable mechanism was provided, the test apparatus of the present invention was able to obtain good measurement results.

実施例１と同様の本発明例の装置、試験条件で実験を行ったが、応力波緩衝部の効果を確認するため、支持機構に直径１６ｍｍの丸棒と断面積の非常に小さいものを使用した試験を行った。応力波緩衝部１３を含む荷重検出装置の模式図を図７に示す。 Experiments were performed using the same apparatus and test conditions of the present invention as in Example 1, but in order to confirm the effect of the stress wave buffer, a 16 mm diameter round bar and a very small cross-sectional area were used for the support mechanism. The test was performed. A schematic diagram of a load detection device including the stress wave buffer 13 is shown in FIG.

表２に得られた結果を示す。いずれの試験条件でも従来型の試験機（図６に結果を記載）を使用するよりは良好な測定結果が得られたが、応力緩衝部１３を設けないＮｏ．１５では支持機構３と荷重検出部２の間に応力波の反射が効率的に起こらず、試験機の別の場所で反射した応力波も重畳してしまうため測定波形に試験条件の影響が見られた。それに対して応力波緩衝部１３を前記（５）記載の本発明の範囲に合う形で設けたＮｏ．１６、１７では応力波の影響のない良好な測定結果が得られた。それに対して荷重検出部２と応力波緩衝部１３の断面積の比が前記（５）記載の本発明範囲にないＮｏ．１８では若干の応力波ノイズの影響が見られた。また、Ｎｏ．１９はＮｏ．１６と同様の応力検出装置を実施例１の支持機構３に取り付けたものである。この場合応力波緩衝部１３は試験結果に悪影響を及ぼさず良好な実験結果が得られた。 Table 2 shows the results obtained. In any of the test conditions, a better measurement result was obtained than when using a conventional testing machine (results shown in FIG. 6). 15, stress waves are not efficiently reflected between the support mechanism 3 and the load detection unit 2, and stress waves reflected at other places on the testing machine are also superimposed. It was. On the other hand, the stress wave buffering portion 13 is provided in the form of No. 1 provided so as to meet the scope of the present invention described in the above (5) . For 16 and 17, good measurement results without the influence of stress waves were obtained. On the other hand, the ratio of the cross-sectional areas of the load detection unit 2 and the stress wave buffer unit 13 is not within the scope of the present invention described in (5) . No. 18 was slightly affected by stress wave noise. No. 19 is No. 19; The same stress detection apparatus as that of No. 16 is attached to the support mechanism 3 of the first embodiment. In this case, the stress wave buffer 13 did not adversely affect the test results, and good experimental results were obtained.

応力波パルス発生機構として図３に示すような中空構造体を用いて試験を行った。この際弾性棒は直径１６ｍｍで全長２ｍのステンレス棒鋼を用いた。この端部に直径５０ｍｍ、厚さ１０ｍｍのステンレス鋼製円盤の中央部にネジ加工を施し、これを弾性棒端にねじ込むことにより中空構造体の受け止め機構１０を構成した。中空構造体９は外径２５．４ｍｍ、肉厚２．３ｍｍ、長さ３００ｍｍの鋼性パイプを用いた。この中空構造体９はばねに押し付けた後に解放し、所定の速度で打ち出した。この中空構造体９が中空構造体の受け止め機構１０に当ることにより応力波パルスが生成し、弾性棒４を通じて試験片を変形させる。今回の試験は試験片のひずみ速度を約６００／ｓｅｃに相当する条件で行った。試験片は実施例１と同様のものを、また、荷重検出部２および支持機構３も実施例１に示したＮｏ．４と同じものを用いた。 A test was conducted using a hollow structure as shown in FIG. 3 as a stress wave pulse generation mechanism. At this time, a stainless steel bar having a diameter of 16 mm and a total length of 2 m was used as the elastic bar. The hollow structure receiving mechanism 10 was configured by threading the end portion of a stainless steel disk having a diameter of 50 mm and a thickness of 10 mm and screwing it into the end of the elastic rod. The hollow structure 9 was a steel pipe having an outer diameter of 25.4 mm, a wall thickness of 2.3 mm, and a length of 300 mm. The hollow structure 9 was released after being pressed against the spring, and was ejected at a predetermined speed. When the hollow structure 9 hits the receiving mechanism 10 of the hollow structure, a stress wave pulse is generated, and the test piece is deformed through the elastic bar 4. This test was performed under the condition corresponding to a strain rate of about 600 / sec. The test piece is the same as that in Example 1, and the load detector 2 and the support mechanism 3 are also No. 1 shown in Example 1. The same as 4 was used.

図８に本発明の試験装置で計測した結果を示す。変形のごく初期に、中空構造体９とその受け止め機構１０が衝突する際の応力波の分散に起因すると思われる振動波形が観測されたが、概ね良好な測定結果を得ることができた。 FIG. 8 shows the results measured with the test apparatus of the present invention. In the very early stage of deformation, a vibration waveform that was thought to be caused by the dispersion of stress waves when the hollow structure 9 and its receiving mechanism 10 collide was observed, but generally good measurement results could be obtained.

本発明例の試験装置の模式図を示す。The schematic diagram of the test apparatus of the example of this invention is shown. 弾性棒と弾性棒固定装置、変位負荷機構で構成される応力波パルス発生機構を示す。A stress wave pulse generation mechanism including an elastic bar, an elastic bar fixing device, and a displacement load mechanism is shown. 中空構造体とその受け止め機構で構成される応力波パルス発生機構を示す。A stress wave pulse generation mechanism composed of a hollow structure and its receiving mechanism is shown. 本発明の荷重検出装置の模式図を示す。The schematic diagram of the load detection apparatus of this invention is shown. 試験装置（従来型）の模式図を示す。The schematic diagram of a test apparatus (conventional type) is shown. 本発明と従来試験法による測定結果の例を示す。The example of the measurement result by this invention and the conventional test method is shown. 応力波緩衝部を含む本発明例の試験装置の模式図を示す。The schematic diagram of the test apparatus of the example of this invention containing a stress wave buffer part is shown. 中空構造体とその受け止め機構で構成される応力波パルス発生機構を用いて計測した本発明の試験装置による測定結果の例を示す。The example of the measurement result by the test apparatus of this invention measured using the stress wave pulse generation mechanism comprised with a hollow structure and its receiving mechanism is shown.

符号の説明Explanation of symbols

１試験片
２荷重検出部兼試験片締結部
３支持機構
４弾性棒
５変位検出用ひずみゲージ位置
６変位計測手段
７弾性棒固定機構
８変位負荷機構（可動部の一部）
９中空構造体
１０中空構造体の受け止め機構
１１固定部
１２溝
１３応力波緩衝部
１４温度制御槽（温度制御機構） DESCRIPTION OF SYMBOLS 1 Test piece 2 Load detection part and test piece fastening part 3 Support mechanism 4 Elastic bar 5 Displacement detection strain gauge position 6 Displacement measuring means 7 Elastic bar fixing mechanism 8 Displacement load mechanism (part of movable part)
9 Hollow structure 10 Receiving mechanism 11 of hollow structure 11 Fixing part 12 Groove 13 Stress wave buffer part 14 Temperature control tank (temperature control mechanism)

Claims

丸棒又は板状の試験片を固定する固定部を有する締結部と、引張荷重又は圧縮荷重を計測する荷重検出部と、前記締結部を固定支持する支持機構と、前記試験片に引張又は圧縮変形を与える可動部からなる装置において、前記締結部と前記荷重検出部を一体化し、前記荷重検出部は前記固定部より前記支持機構側に設置され、かつ
（前記固定部における前記締結部の断面積）≦（荷重検出部における前記締結部の断面積）＜（支持機構の断面積）
の条件を満たし、かつ、前記可動部が一端側に試験片が結合される弾性棒と、該弾性棒における試験片と反対側の端部を固定する変位負荷機構と、試験片と変位負荷機構との間の位置に配設された弾性棒固定機構とを有し、弾性棒固定機構によって固定された弾性棒を変位負荷機構によって変形させて弾性エネルギーを蓄えた後、弾性棒固定機構の固定を解除することにより応力波パルスを発生させて弾性棒を通じて試験片に伝播させる応力波パルス発生機構により構成されることを特徴とする高速引張又は高速圧縮荷重計測装置。 A fastening part having a fixing part for fixing a round bar or a plate-like test piece, a load detection part for measuring a tensile load or a compression load, a support mechanism for fixing and supporting the fastening part, and a tension or compression on the test piece. In an apparatus including a movable part that imparts deformation, the fastening part and the load detection part are integrated, and the load detection part is installed on the support mechanism side from the fixing part, and (the disconnection of the fastening part in the fixing part is performed). Area) ≦ (Cross sectional area of the fastening part in the load detection part) <(Cross sectional area of the support mechanism)
And a movable load is connected to one end side of the elastic rod, and an elastic rod to which the end of the elastic rod opposite to the test piece is fixed, a test piece and a displacement load mechanism The elastic rod fixing mechanism is disposed between the elastic rod fixing mechanism and the elastic rod fixed by the elastic rod fixing mechanism is deformed by the displacement load mechanism to store elastic energy, and then the elastic rod fixing mechanism is fixed. A high-speed tensile or high-speed compressive load measuring device comprising a stress wave pulse generating mechanism for generating a stress wave pulse by releasing the wave and propagating it to a test piece through an elastic rod .

前記締結部と弾性棒端の変位を計測し、その差から試験片の変位を計測する変位計測手段を有することを特徴とする請求項１に記載の高速引張又は高速圧縮荷重計測装置。 The high-speed tensile or high-speed compressive load measuring device according to claim 1, further comprising a displacement measuring unit that measures the displacement of the fastening portion and the end of the elastic rod and measures the displacement of the test piece from the difference therebetween.

締結部が円柱状であり、板状の試験片の場合には試験片を固定する溝を設置し、丸棒状の試験片の場合には試験片を固定するネジ穴が設置された締結部を持ち、前記荷重検出部における締結部の直径Ｄ（ｍｍ）と、前記溝またはネジ穴下端から支持機構上端までの長さＬ（ｍｍ）の比が０．３≦Ｌ／Ｄ≦１０を満たすことを特徴とする請求項１又は２に記載の高速引張又は高速圧縮荷重計測装置。 In the case of a plate-shaped test piece, a fastening part is provided with a groove for fixing the test piece. In the case of a round bar-like test piece, a fastening part with a screw hole for fixing the test piece is provided. And the ratio of the diameter D (mm) of the fastening portion in the load detection portion to the length L (mm) from the lower end of the groove or screw hole to the upper end of the support mechanism satisfies 0.3 ≦ L / D ≦ 10 The high-speed tensile or high-speed compressive load measuring device according to claim 1 or 2 .

前記荷重検出部における前記締結部の断面積Ａ０（ｍｍ^２）と、前記支持機構の断面積Ａ１（ｍｍ^２）との比が
２≦Ａ１／Ａ０
を満たすことを特徴とする請求項１〜３のいずれかに記載の高速引張又は高速圧縮荷重計測装置。 The ratio of the cross-sectional area A0 (mm ² ) of the fastening portion in the load detection unit to the cross-sectional area A1 (mm ² ) of the support mechanism is 2 ≦ A1 / A0.
The high-speed tensile or high-speed compression load measuring device according to any one of claims 1 to 3, wherein

丸棒又は板状の試験片を固定する固定部を有する締結部と、引張荷重又は圧縮荷重を計測する荷重検出部と、前記締結部を支持する支持機構と、前記試験片に引張又は圧縮変形を与える可動部からなる装置において、前記締結部と前記荷重検出部を一体化し、前記荷重検出部は前記固定部より前記支持機構側に設置され、かつ
（前記固定部における前記締結部の断面積≦（荷重検出部における前記締結部の断面積）≦（支持機構の断面積）
の条件を満たし、かつ前記可動部が弾性棒を有する応力波パルス発生機構により構成されるとともに、前記荷重検出部における前記締結部の断面積をＡ０としたときに
２≦Ａ２／Ａ０
を満たす断面積Ａ２（ｍｍ^２）を持つ応力波緩衝部を、前記締結部と前記支持機構の間に配置することを特徴とする高速引張又は高速圧縮荷重計測装置。 A fastening part having a fixing part for fixing a round bar or a plate-like test piece, a load detection part for measuring a tensile load or a compression load, a support mechanism for supporting the fastening part, and a tensile or compressive deformation of the test piece. The fastening part and the load detection part are integrated, and the load detection part is installed closer to the support mechanism than the fixing part, and (a cross-sectional area of the fastening part in the fixing part) ≦ (Cross sectional area of the fastening part in the load detection part) ≦ (Cross sectional area of the support mechanism)
And the movable part is constituted by a stress wave pulse generation mechanism having an elastic rod, and 2 ≦ A2 / A0 when the sectional area of the fastening part in the load detection part is A0
A high-speed tensile or high-speed compressive load measuring device, wherein a stress wave buffer portion having a cross-sectional area A2 (mm ² ) satisfying the above condition is disposed between the fastening portion and the support mechanism.

前記可動部が、一端側に試験片が結合される弾性棒と、該弾性棒における試験片と反対側の端部を固定する変位負荷機構と、試験片と変位負荷機構との間の位置に配設された弾性棒固定機構とを有し、弾性棒固定機構によって固定された弾性棒を変位負荷機構によって変形させて弾性エネルギーを蓄えた後、弾性棒固定機構の固定を解除することにより応力波パルスを発生させて弾性棒を通じて試験片に伝播させる応力波パルス発生機構により構成されることを特徴とする請求項５に記載の高速引張又は高速圧縮荷重計測装置。 The movable portion is located at a position between the elastic rod to which the test piece is coupled at one end, a displacement load mechanism for fixing the end of the elastic rod opposite to the test piece, and the test piece and the displacement load mechanism. The elastic rod fixing mechanism is disposed, and the elastic rod fixed by the elastic rod fixing mechanism is deformed by the displacement load mechanism to store the elastic energy, and then the elastic rod fixing mechanism is released to release the stress. 6. The high-speed tensile or high-speed compressive load measuring device according to claim 5 , wherein the high-speed tensile or high-speed load measuring device is constituted by a stress wave pulse generating mechanism that generates a wave pulse and propagates it to a test piece through an elastic rod .

前記可動部が、一端側に試験片が結合される弾性棒と、該弾性棒に応力波パルスを発生させる中空又は中実の構造体と、上記該弾性棒における試験片と反対側の端部に一体化させた、構造体の受け止め機構とを有し、上記構造体を受け止め機構に向けて射出することにより弾性棒における上記構造体の受け止め機構側の端面に応力波パルスを発生させ、弾性棒を通じて試験片に伝播させる応力波パルス発生機構により構成されることを特徴とする請求項５に記載の高速引張又は高速圧縮荷重計測装置。 The movable part includes an elastic bar to which a test piece is coupled at one end side, a hollow or solid structure for generating a stress wave pulse on the elastic bar, and an end part of the elastic bar opposite to the test piece. And receiving the structure to the receiving mechanism to generate a stress wave pulse on the end surface of the elastic body on the receiving mechanism side of the structure. 6. The high-speed tensile or high-speed compressive load measuring device according to claim 5 , wherein the high-speed tensile or high-speed load measuring device is configured by a stress wave pulse generating mechanism that propagates to a test piece through a rod .

更に、試験片の温度を可変とする温度制御機構を備えることを特徴とする請求項１〜７のいずれかに記載の高速引張又は高速圧縮荷重計測装置。 Furthermore, the temperature control mechanism which makes temperature of a test piece variable is provided, The high-speed tension or high-speed compression load measuring apparatus in any one of Claims 1-7 characterized by the above-mentioned.