© 2017 SPIE. Image analysis with ultra-high-speed camera and two dimensional dynamic numerical analysis are applied to study the rapid unstable growth of wing crack under the uniaxial compression. Growing wing crack terminates and restarts its unstable rapid growth in some cases. Such a termination and restart behavior of the growing crack is studied through the experiment and numerical analysis in this work. First, rectangle transparent specimen, including the initial crack inclined to the compressive axis, is subjected to the uniaxial compression till the wing cracks start unstable rapid growth from both ends of the initial crack. Images of growing cracks and those of stress distribution, visualized as the photo-elastic fringe pattern, are captured by the high speed camera with the frame rate of 500k frames per second. The behavior of growing crack and the change in the stress field due to the crack growth are discussed through the captured images. Next, two dimensional dynamic numerical analysis is carried out. PDS-FEM (Particle Discretization Scheme), which allows the discontinuity of the displacement in the continuous analytical domain, is combined with the central difference time integration scheme to simulate the rapid unstable growth of the wing crack dynamically. The accuracy of the proposed simulation is discussed through the comparison with the images, captured by the experiment.

Image analysis with ultra-high-speed camera and dynamic numerical analysis are applied to the unstable crack growth of wing crack under the uniaxial compression. During the unstable growth, growing wing crack terminates and restarts their growth in some cases. The termination and restart behavior of the growing crack is discussed through the experiment and numerical analysis in this research.
First, images of rapid propagation of wing cracks under uniaxial compression are captured by the ultra-high-speed camera with the frame rate of 500k frames per second. Stress field around the moving crack tip is visualized by means of photo-elastic technique, and images of the resultant fringe patter are also captured by the camera.
Next, two dimensional dynamic numerical analysis is performed. PDS-FEM (Particle Discretization Scheme), which allows the discontinuity of the displacement in the continuous body, is combined with the central difference time integration scheme to simulate the unstable growth of the wing crack dynamically. The accuracy of the simulation is discussed through the comparison with the images which are captured by the high speed camera.

3D wing crack growth is not a well understood phenomenon, although it is one of the key mechanisms of the failure of brittle materials under compression. Using PDS-FEM, we simulated the growth of 3D wing cracks emerging from pre-existing cracks in blocks of brittle linear elastic solids, under compression. The complex 3D wing crack profiles are reproduced with PDS-FEM, which uses non-overlapping shape functions of conjugate geometries to approximate functions and their derivatives. PDS-FEM provides numerically efficient failure treatment for modeling 3D cracks, making use of the numerous discontinuities in the approximated displacement field. Large scale models with several million elements are used to reproduce the experimentally observed details of wing crack profiles. The bending of crack surfaces at the tip of mode-I regions, extension of wing cracks and the growth of tensile openings or petal cracks at mode-III regions are reproduced, demonstrating the applicability of PDS-FEM for studying 3D wing crack growth phenomena. © (2014) Trans Tech Publications, Switzerland.

Image analysis with ultra-high-speed camera is applied to the unstable crack growth under quasi-static uniaxial compression. Stress field around the moving crack tip in the transparent specimen is visualized by means of photo-elastic technique and images of growing cracks and the stress field are captured with the frame rate of 250,000 fps. As a result, it is revealed that wing cracks start initiation at each end of the initial defect with time lag, and the time difference in their initiation corresponds to the travelling time of the stress wave, which is released due to the growth of the primary crack, from one end of the initial defect to the other end.

In 2010, we developed a BSI image sensor capable of capturing images at 16Mfps. A preliminary evaluation result of the sensor is summarized. A concept of a next generation ultra-high-speed image sensor is also presented, which has a new function, image signal accumulation, in addition to the ultra-high-speed and the ultra-high-sensitivity.

In 2002, we reported a CCD image sensor with 260x312 pixels capable of capturing 103 consecutive images at 1,000,000 frames per second (1Mfps) [1]. We named the sensor "ISIS-V2", for In-situStorage Image Sensor Version 2. 103 memory elements are attached to every pixel generated image signals were instantly and continuously stored in the in-situstorage without being read out of the sensor. The ultimate high-speed recording was enabled by this parallel recording at all pixels. In 2006, the color version, ISIS-V4, was reported [2]. In 2009, we developed ISIS-V12, a backside-illuminated image sensor mounting the ISIS structure and the CCM, charge-carrier multiplication, on the front side [3]. The CCM is a CCD-specific efficient signal-amplification device. CCM, combined with the BSI structure and cooling, achieved very high sensitivity. The ISIS-V12 was a test sensor intended to prove the technical feasibility of the structure. The maximum frame rate was 250kfps for a charge-handling capacity of Qmax=10,000e- and 1Mfps for a reduced Qmax. The pixel count was 489x400 pixels. For backside-illuminated (BSI) image sensors, metal wires can be placed on the front surface to increase the frame rate without reducing fill factor or violating uniformity of the pixel configuration. It has been proved by simulations that 100Mfps is achievable by introducing innovative technologies including a special wiring method [4]. We now report on ISIS-V16, developed by incorporating technologies to increase the frame rate with those to achieve very high sensitivity, which was confirmed by evaluation of ISIS-V12. The performance specification of ISIS-V16 is summarized in Fig. 23.4.1. © 2011 IEEE.

This paper presents the formulation of PDS-FEM (particle discretization scheme finite element method) in three dimensional setting and Monte-Carlo simulation of crack propagation by PDS-FEM. The probability density function of the crack paths in a plate with two parallel initial cracks located in an anti-symmetric manner is computed in order to evaluate the statistical and spatial distribution of the crack paths, and it is shown that the crack path in an ideally homogeneous plate is unstable. The simulation results are compared with experimental data. Besides, Monte-Carlo simulation of crack propagation in a heterogeneous elasto-plastic cylinder (as a simplified model of concrete) under uniaxial tension has been carried out and its statistical behavior is discussed. © 2009 Elsevier Ltd. All rights reserved.

It is known that the crack path varies due to various disturbance factors, such as a heterogeneity of the material and interaction between cracks. Images of crack growth from parallel cracks under the quasistatic loading is captured by the ultra-high-speed camera, and the stress field around the propagating crack tip is visualized with the aid of dynamic photo-elastic technique in this work. First, the stability and the distribution pattern of crack path are discussed from the captured images. And then, the accuracy of the numerical quasi-static analysis of crack growth is studied through the comparison with the visualized stress field around the propagating crack tip.

Unstable crack growth under quasi-static loading condition is studied both experimentally and numerically in this work. Image analysis is applied to the experimental study. Stress field around the propagating crack tip is visualized by means of photo-elastic technique, and images of the unstable crack growth and the visualized stress field around the propagating crack-tip are captured by the ultra-high-speed camera with the frame rate of 1000 000 fps. Images are successfully captured at every 0.3 mm crack growth. Next, the numerical simulation technique to simulate the unstable crack growth without the rearrangment of nodes and elements is proposed. In the proposed technique, X-FEM is extended to include the dynamic phenomena. The result of the simulation is directly compared with the experimental observation.As a result of comparison, numerically simulated fringe patterns have a good agreenment with the experimentally observed ones, and hence, it is shown that the proposed algorithm has a sufficient accuracy.

In this paper, fracture analysis that uses PDS-FEM is extended to the three-dimensional setting. Monte-Carlo simulation is carried out for a plate with two parallel cracks which are located in an anti-symmetric mannter. The probability density function of the crack path is calculated in order to evaluate the statistical and spatial distribution of the crack path, and it is shown that the crack path of an idearly homogenous plate is unstable so that small local heterogeneity produces large variaibility in the crack path. The simulation results are compared with experimental data, and some discussions are made for the PDS-FEM fracture analysis.

An ultra-high speed camera of IMfps was applied to visualize the crack propagation. Change of stress field around the propagating crack tip was captured as a change of the fringe pattern by means of the photo-elastic imaging technique. Newly developed video trigger system is employed to detect the occurrence of the crack propagation as a trigger in the experiment. The trigger successfully perceived the initiation of the crack propagation stably. Also its response time was fast enough even for the image capturing with IMfps. As a result, it is revealed that the elastic wave, propagating in the continuous body, has a significant effect on the velocity and kinking behavior of the propagating crack. © 2007 SPIE-IS& T.

An image sensor for an ultra-high-speed video camera was developed. The maximum frame rate, the pixel count and the number of consecutive frames are 1,000,000 fps, 720 × 410 (= 295,200) pixels, and 144 frames. A micro lens array will be attached on the chip, which increases the fill factor to about 50%. In addition to the ultra-high-speed image capturing operation to store image signals in the in-situ storage area adjacent to each pixel, standard parallel readout operation at 1,000 fps for full frame readout is also introduced with sixteen readout taps, for which the image signals are transferred to and stored in a storage device with a large capacity equipped outside the sensor. The aspect ratio of the frame is about 16:9, which is equal to that of the HDTV format. Therefore, a video camera with four sensors of the ISIS-V4, which are arranged to form the Bayer's color filter array, realizes an ultra-high-speed video camera of a semiHDTV format.

A post-digital processing for a convertible triple in-situ storage image sensor (ISIS) camera is developed in this work. The convertible Triple-ISIS camera is converted from three single ISIS cameras by users. The camera has the frame rate of 1Mfps, and is expected to be a powerful tool for scientific and engineering measurements, such as color imaging, imaging with different light wave bands, and so on. Position and sensitivity adjustments are required after conversion. Post-digital processing is employed for the adjustments instead of the mechanical ones, since the conversion is expected to be done by users. As the post-digital processing, an image of a test pattern for calibration is captured by the converted ISIS camera. The position and sensitivity are adjusted only from that image. Color imaging is employed as an example of applications. Images which are captured by three ISISes are adjusted by means of the proposed position and sensitivity adjustments, and are piled up. The accuracy of the adjustments are discussed through the resultant color pictures and movies captured at 125 Kfps.

An image sensor for a video camera of 1 000 000 frames per second (fps) was developed. The specifications of the developed sensor are as follows: 1) frame rate: 1 000 000 fps 2) pixel count: 81 120 (= 312 × 260) pixels 3) total number of successive frames: 103 frames 4) gray levels: 10 b and 5) open area of each pixel (fill factor): 580 square micrometers (13%). The overwriting function is installed for synchronization of image capturing with occurrence of the target event. Sensitivity is significantly high with the large photogate. Some innovative technologies were introduced to achieve ultrahigh performance, including slanted linear CCD in situ storage, curving design procedure, and a CCD switch with fewer metal shunting wires. They are applicable to the development of other new high-performance image sensors.

An image sensor of 1,000,000 fps with image storage for consecutive 103 images is developed, which is called ISIS, In-situ Storage Image Sensor. Various innovative ideas support this achievement. Each pixel of the sensor has its own in-situ storage area of image signals during an image capturing phase, image signals generated in the photo-sensitive areas of all pixels are simultaneously recorded in the in-situ storage areas without being readout from the sensor, which realizes parallel recording at all pixels and, thus, image capturing at the ultimate high frame rate.

撮影速度100万枚/秒のビデオカメラ用撮像素子を開発した.撮影中は全画素並列で一斉に各画素の周辺に組入れられた記録領域に画像情報を蓄積するので究極の高速化が可能である.このような素子を画素周辺記録型撮像素子(ISIS: In-situ Storage Image Sensor)と呼ぶ.開発した素子の記録要素は少し斜めに置かれた通常の直線CCDで,非常に単純な構造である.ドレーンも組入れられており,103枚の連続上書き撮影が可能である.試験撮影により高感度,高画質であることも確かめられた.

A single-chip CCD image sensor captures > 100 successive images at > 1 Mframes/s. The pixel count of test chip is 312 × 260 (=81,120) pixels. Charge handling capacity is 40 k electrons. Grey levels are 10b. Fill factor is 13%. On-chip overwriting mechanism makes possible continuous recording of the latest image signals, draining the old ones to the substrate.

Presented in this paper is an outline of the R and D activities on high-speed video cameras, which have been done in Kinki University since more than ten years ago, and are currently proceeded as an international cooperative project with University of Applied Sciences Osnabruck and other organizations. Extensive marketing researches have been done, (1) on user's requirements on high-speed multi-framing and video cameras by questionnaires and hearings, and (2) on current availability of the cameras of this sort by search of journals and websites. Both of them support necessity of development of a high-speed video camera of more than I million fps. A video camera of 4,500 fps with parallel readout was developed in 1991. A video camera with triple sensors was developed in 1996. The sensor is the same one as developed for the previous camera. The frame rate is 50 million fps for triple-framing and 4,500 fps for triple-light-wave framing, including color image capturing. Idea on a video camera of 1 million fps with an ISIS, In-situ Storage Image Sensor, was proposed in 1993 at first, and has been continuously improved. A test sensor was developed in early 2000, and successfully captured images at 62,500 fps. Currently, design of a prototype ISIS is going on, and, hopefully, will be fabricated in near future. Epoch-making cameras in history of development of high-speed video cameras by other persons are also briefly reviewed.

During the Great Hanishin-Awaji Earthquake, many steel bridge structures experienced brittle fractures, following the large scale deformation of their members. Hence, in this work, various material tests are performed on specimens which are made out of damaged steel bridge structures. The plastic strain, induced during the earthquake, is estimated through the change in their material properties. And then, the embrittleness of the steel due to the induced plastic strain is discussed, in order to study the mechanism of the occurrence of the brittle fracture during the earthquake.

The ISIS, In-situ Storage Image Sensor, may achieve the frame rate higher than 1,000,000 pps. Technical targets in development of the ISIS are listed up. A layout of the ISIS is presented, which covers the major targets, by employing slanted CCD storage and amplified CMOS readout. The layout has two different sets of orthogonal axis systems: one is mechanical and the other functional. Photodiodes, CCD registers and all the gates are designed parallel to the mechanical axis system. The squares on which pixels are placed form the functional axis system. The axis systems are inclined to each other. To reproduce a moving image, at least fifty consecutive images are necessary for ten-second replay at 5 pps. The inclined design inlays the straight CCD storage registers for more than fifty images in the photo-receptive area of the sensor. The amplified CMOS readout circuits built in all the pixels eliminate line defects in reproduced images, which are inherent to CCD image sensors. FPN (Fixed Pattern Noise) introduced by the individual amplification is easily suppressed by digital post image processing, which is commonly employed in scientific and engineering applications. The yield rate is significantly improved by the elimination of the line defects.

本研究の目的は，断層のスーパーシア破壊（超せん断破壊）の発生に与える地盤の不均一性の影響を，実験と数値解析を用いて明らかにすることである．本研究では実験室内でスーパーシア破壊を再現し，画像計測を用いて破壊の進行条件と進行状況を明らかにする．画像計測には毎秒1,000万枚撮影可能な超高速ビデオカメラを適用し，時間分解能の高い画像計測を行う． 本年度はスーパーシア破壊を伴う実験を行う目的で，衝撃試験装置の製作，装置の性能評価，実験に適した供試体の作成を行った．本年度に製作された試験装置では，空気圧を用いて加速したΦ25×50の鋼製円筒飛翔体を装置上に固定された供試体に衝突させることにより，供試体中でスーパーシア破壊を発生させる．供試体固定部には載荷装置を組み込み，圧縮荷重下でのスーパーシア破壊の検討を計画している． 製作された試験装置の性能評価として，飛翔体の飛翔速度の計測を行った．計測には超高速ビデオカメラによる画像計測を適用した．計測結果として空気圧1.2MPaで飛翔体の速度は約53m/s，1.4MPaで約67m/sに達しており，製作された実験装置はスーパーシア破壊を発生させるために十分な能力を有することが確認された． 供試体として透明脆性材料であるエポキシ樹脂を用いて140×140×10mmの矩形供試体を作成した．矩形供試体を底面から70mmの位置で底面に平行に切断し，切断面を滑面加工した上で上下部を再度接着することにより衝撃試験用の供試体を作成した．接合面上部に横軸方向に衝撃荷重を載荷することで接着面に沿って破壊を発生させる．本年度に行った予備実験では，切断面に沿った破壊の進行速度は300m/s程度であった．スーパーシア破壊は再現できなかったが，接着面に沿って破壊を発生させることには成功し，予備試験としては十分な結果を得られた．

The mechanism of crack branching is studied experimentally and numerically in this work. The image measurement with high temporal and high spatial resolutions is applied to the crack branching behavior. It is observed that the singe propagation crack bifurcates into multiple partial cracks and they repeats re-branching and merging while propagating parallel to each other, before the bifurcation point which is confirmed in the specimen after the experiment. They change the propagating directions to those of moving away from each other, and grow into the branching cracks. It's also concluded that the fluctuation of the crack propagation speed before the bifurcation is caused due to the re-branching and merging behavior of partial cracks. As the numerical simulation, high-order PDS-FEM is applied to the dynamic simulation and the crack propagation is successfully simulated.

The unstable crack growth of the wing crack under the uniaxial compression is discussed experimentally and numerically. In experimental discussion, images of unstable growth of two and three dimensional wing cracks are captured by the ultra-high-speed camera with the frame rate of 500k frames per second. Stress field in the specimen including propagating cracks is visualized by means of photo-elastic technique, and images of the resultant fringe patter are also captured by the high-speed camera successfully. Next, two dimensional dynamic numerical analysis is performed. PDS-FEM (Particle Discretization Scheme), which allows the discontinuity of the displacement in the continuous body, is combined with the contact surface algorithm, and applied to simulate the unstable growth of the wing crack dynamically. The accuracy of the simulation is discussed through the comparison with the images which are captured by the high speed camera, and they showed a good agreement.

To study the unstable crack growth mechanism under compressive loading, the experiment of two dimensional crack growth under uni-axial compression, the experiment and numerical simulation of three dimensional inner crack growth has been performed. Image analysis with ultra-high-speed camera is applied to the two dimensional unstable crack growth under quasi-static uniaxial compression. Stress field around the moving crack tip is visualized by means of photo-elastic technique and images of growing cracks and the stress field are captured with the frame rate of 250,000 fps. As a result, it is revealed that the crack growth is affected by the stress wave travelling the specimen. Image analysis with ultra-high speed camera is also applied to the three dimensional inner crack growth, and the growth is visualized successfully. Numerical analysis with PDS-FEM technique is applied to the three dimensional inner crack growth, and the result shows a good agreement with the experimental result.

Unstable crack growth under the quasi-static loading condition is studied experimentally and numerically. Images of the crack growth and the stress distribution around the growing crack tip, which is visualized by using photo-elastic technique, are successfully captured by the ultra-high-speed video camera with the frame rate of 1Mfps. Next, numerical algorithm to simulate the unstable crack growth is proposed in this work. The simulation result shows a good agreement with the experimental result, and it is shown that the proposed algorithm has the sufficient accuracy.

本年の研究では,静的載荷時における亀裂の発生,進展過程の画像解析を行うとともに,供試体へのマーキング手法の開発とマーク検出手法の改善を行った. 沖中等はガウス粒子を供試体表面にマーキングすることにより画像解析対象表面に既定の濃度分布を与えた.これを撮像素子表面の光電変化部の位置・形状の情報と組合わせることにより,粒子検出精度が0.01画素程度の高性能な画像解析手法の開発に成功している.この手法は高精度である一方,実験の下準備に多大な手数を要する上,鋼材等のガウス粒子のマーキングが困難な材料も存在する. そこで本年は、スプレー・マーキングによる簡易マーキング手法を検討した.黒色スプレーを用いて供試体表面に微小粒子をマーキングすることにより,高解像度かつ簡便で金属等にも応用可能な画像解析手法の開発を試みた.この手法の開発にあたっては,微小粒子の検出,変形前・変形後での粒子の追跡,検出された粒子位置の変位からのひずみの算出の3つのポイントが問題となる.本研究では,粒子の検出には沖中等の開発した粒子追跡手法を応用,粒子の追跡にはカルマン・フィルターを用いた追跡手法を適用,ひずみの算出にはメッシュレス法で用いられる重み付き近似による算出を適用した.尚,カルマン・フィルターを用いた追跡手法は流体分野で開発され,良好な結果を与えている手法である. 硬石膏を用いて作成した角柱供試体の3点曲げ試験に開発さらた画像解析手法を適用し,亀裂発生前後の供試体表面のひずみ分布を検討した.画像解析には600万画素のNIKON-D70を使用した. 開発された手法の精度は,ガウス粒子を用いた高精度画像解析手法との比較で検討した.結果,簡便で高解像度なひずみ分布が得られたものの,その精度には改善の余地を残すことが明らかとなった.

1.00万枚/秒の高速ビデオカメラの開発 100万枚/秒の超高速ビデオカメラの開発に成功した。これは主として別予算を用いて開発したものであるが、レーザー・マーキングPTVにとっても必須の計測機器である。 2.高速ビデオカメラとホログラム・レーザー・ビームを用いた表面張力測定手法の開発 ホログラムを用いて、多数のレーザー・ビームを発生する方法を実際の計測に適用した。 通常の表面張力測定装置は、細い白金線で作った輪を、水中からゆっくり引き上げ、表面が瞬間的に破壊されて、輪が水面から抜ける瞬間の引っ張り力を測定して表面張力に換算する。 自然界の水面のように、水面に薄い化学物質の膜が形成されているような場合には、この方法による測定は不安定になることは研究代表者らにより指摘されている。すなわち輪が水面をわずかに持ち上げた状態では。輪を成す細線の両側に水面勾配が生じ、それにより、水面が流れ、水面の化学物質の層が薄くなる。 実験水槽の水底から多数の並行レーザー・ビームを水面に向けて照射し、水面上で多数の点として撮影する。中央付近に振動を与え表面張力波を発生させると、水面でのレーザー・ビームの屈折により多数の点像が高速で振動する。これを高速ビデオカメラで撮影し、点像をPTV解析することで、表面張力波の伝播速度や波長を計測することができる。微小振幅表面張力の理論にこれらの値を代入することで表面張力の値を逆算する。純水に対して適用した結果、この方法により、現段階でも誤差10%以内で表面張力を測定できることがわかった。

本研究は磯焼け現象で藻場が消失した海域や貧栄養化した海岸域に無機質の栄養素を多孔質材料(ポーラスコンクリート)内に挿入して沿岸海域に沈漬し、それらの栄養源を徐々に海域に溶出させ、藻場を再生または造成する方法を提案した。室内試験では無機系の栄養塩類を特殊なポリマーで2層構造としてシールし、コンクリートの製造時においても破壊されない状態として挿入し、肥料成分がコンクリートの強度や耐久性に与える影響について検討した。さらに実海域にこの種の多孔質複合材料を沈漬し、それらの機械的性質や藻類をはじめ各種生物の付着状態を照査した。これらの調査結果から、この手法は海岸水域の環境創造用材料としての利用が可能なることを示唆した。 具体的には次に示す内容の研究を実施し、それぞれ以下の研究成果を得た。 1)表面処理した粒状肥料が多孔質コンクリートの製造と硬化後の物性に与える影響につき調査した。 肥料成分をシールした粒状物を多孔質コンクリート内に混合挿入する手法を示した。また、硬化体の機械的性質として材令と圧縮強度をはじめ各種強度の関係を明らかにした。化学的性質としては、多孔質硬化体からの肥料成分の溶出状況を把握すると共に溶出量の制御方法を検討した。 2)自然海域に沈漬した肥料を混入した多孔質複合材料の諸性質 自然の海水中に上記の複合材料を沈漬した場合、強度等の機械的性質と肥料成分の溶出特性を経時的に調査した。その結果、骨材空隙への結合材量とその強度が複合材の耐久性と肥料成分の溶出に大きく影響することを明らかにした。 3)肥料を混入した多孔質複合材料への各種海洋生物の付着性状を検討した。 ポリマーで表面処理した肥料成分と鉄成分を多量に含有する鉄鉱石や転炉スラグを骨材として連続した空隙を有する多孔質コンクリートの硬化体への海藻類や小動物類の付着性状を調査した。 4)平成11年度から平成12年度に実施した研究結果を取り纏めた。

阪神・淡路大震災において、多くの鋼構造物で座屈や脆性破壊といった不安定破壊現象が発生した。これらの脆性破壊のうち、多くの事例では部材の大規模変形後に亀裂の発生・進展が見られ、地震により導入された塑性予歪により鋼材が脆化、それにより亀裂の不安定成長が誘発された可能性が否定できない。そこで阪神・淡路大震災により被災した阪神道路公団神戸線の鋼製橋脚から採取した試験片について様々な材料試験を施した結果、鋼材に導入された予歪みの板厚方向平均は、座屈部で12.3%、非座屈部で4.4%と言う値が得られた。これは既往の研究で得られた解析結果のの数倍に達する値であり、その導入課程は注目に値する。そこで本研究では、これらの歪の導入過程を明らかにする目的で、阪神神戸線P-585橋脚の地震時挙動を衝撃問題の視点から解くことに着目した。歪速度依存性を持つ構成則を導入することにより、衝撃による歪速度が構造物の弾塑性挙動に与える影響について検討を加えた。解析の結果、観測された地震動を入力データとして用いた場合には、橋脚の歪速度は10^<-2>のオーダーを持つ事が分かった。これは一般に鋼材が歪速度依存性を発揮する下限を上回る値であり、地震時の鋼構造物の弾塑性挙動の解析に歪速度依存性を考慮することが有効であることを示唆している。一方、導入された塑性歪みは1%程度であり、実験により観測された値を大きく下回った。実験によって得られた規模の塑性歪を導入するためには、観測された地震動の4倍程度の上下動を与える必要があり、解析の条件を考慮しなおす必要が認められた。