Name: a novel biaxial testing apparatus for the determination of forming limit under hot stamping conditions
Uploaded: 2017-04-04T12:30:00.000+00:00
Duration: 7 min 40 s
Description: Watch this Scientific Journal Video about A Novel Biaxial Testing Apparatus for the Determination of Forming Limit under Hot Stamping Conditions at JoVE.com

This research was supported by the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement No. 604240, project title "An industrial system enabling the use of a patented, lab-proven materials processing technology for Low Cost forming of Lightweight structures for transportation industries (LoCoLite)."

試料の調製<ol><li>機械平坦ドッグボーン及びレーザーカッターや一軸、平面ひずみを含む異なるひずみ経路における成形性試験のためのコンピュータ数値制御（CNC）フライス盤を（使用して商業的材料のアルミニウム合金6082（AA6082）から十字形試験片、及び、等二軸ひずみ状態）。 </li><li>中央ゲージ領域にノギスで三回それぞれ十字試料と各ドッグボーン試験片の厚さを測定し平均値を計算します。十字形試料におけるゲージ部の厚さが0.7±0.05mmで一軸試験片の厚さが1.5±0.1mmであることをことを確認してください。 </li><li> （1,093°Cまでの温度に耐えることができる）、難燃性、黒色スプレー塗料を使用して十字形試験片の上面全体をスプレーペイント。ペイントが乾燥するまで待ち、その後、確率的に作成するために、アームの長さから、難燃性、白色塗料の点をスプレー（ 図1の例を参照）、DICシステムによって認識されるパターンを噴霧します。 </li><li>溶接試験片の（反対側の塗装面に）裏面の中央に熱電対の一対。温度変化の履歴を監視し、制御するための一軸試験機のフィードバック温度制御システムに熱電対のもう一方の端を接続します。 </li></ol>二軸試験装置の2組立<ol><li>ベースプレート、中心軸、入出力回転可能なプレート、キャリッジ、クランプ、ガイドレール、及び剛性連接棒（組み立てられた装置は、 図2に示されている）を含む、二軸試験装置のすべての部品を組み立てます。 <ol><li>一軸引張力を与える一軸引張試験機を、抵抗加熱の可動ジョーに直接接続ロッド、カップル入力回転板を用いました。中央駆動シャフトに結合入力回転板と夫婦出力回転板に、この中央ドライブシャフト。 </li><li>それによってそれは回転軸の周りに結合される出力回転板を回転させ、回転軸の周りの入力回転板の回転が駆動軸を回転させることを確認してください。 </li><li>出力回転板上の接続点のいずれかに剛性連結ロッドの一端に、夫婦それぞれ。カップルキャリッジのいずれかにもう一方の端。 注：これは、試料ホルダーとキャリッジが十字型試験片に軸力を適用することができ、低摩擦でガイドレールに沿って前後にスライドするようになります。 </li><li>スクリューボルトを用いて、試料ホルダと天板とキャリッジに十字形の片の各アームをクランプ。 </li></ol></li><li> 図3（A）に示すように、一軸引張試験機のチャンバー内でグリップを設定します。ステンレス鋼及び銅から作られているグリップ、各対の4本の溶接用ケーブルを取り付け、respectively、従って電力供給に溶接ケーブルを接続します。 注：溶接ケーブルの導体面積を50mm 2であり、電流定格は345 Aです。 <ol><li>一軸引張試験機の2つのジョーに把持し、二軸試験装置のクランプを入れて（ 図3（A））の内部に締め。 </li></ol></li><li> 図3（B）に示すように、一軸引張試験機のチャンバー内で二軸試験装置を設定します。 <ol><li> 2つのフレームを使用して、上部にボルトねじとベースプレートの下側​​には、一軸引張試験機のチャンバ内に装置を固定します。 </li><li>二軸試験装置の上部に試料ホルダーに試料を入れました。 </li><li>検体の各クランプ領域に溶接用ケーブルの各端子を接続します。 </li></ol></li></ol>暖房および焼入れシステムの3.セットアップ<ol><li>密コ抵抗加熱のための電極として機能ステンレス天板に被検体のnnect各クランプ領域。 </li><li>各クランピング領域の上部プレートにクリンプリング端末との溶接ケーブルを締め。 </li><li> Connectは、8000キロ/冷却用m 2の圧力で調整された空気供給源と高流量急冷システムへのホースとノズルをフレア。 </li><li>試料の中央領域に検体の腕から空気を吹き出すように4個のノズルを使用します。 注：ノズルは、カメラの視野から中央ゾーンを阻止避けるために、冷却用ゲージセクション上に向けていません。 </li></ol> DICシステムの4.セットアップ<ol><li>コンピュータにマイクロレンズをDIC系の高速カメラを接続します。 25のFPS、50のFPS、及び（0.01 /秒、0.1 /秒及び1 / sで、それぞれの延伸歪み速度でのテストのために）フレームレートのメニューから500 fpsにカメラのフレームレートを調整します。すべてのIの解像度を設定します。1280×1024ピクセルの魔術師。 注：フレームレートが収集するデータポイントの数によって異なります。少なくとも200個のデータポイントは、上記の設定を使用して収集することができます。 </li><li>高歪速度でのテストのための300 Wのパワーで追加のスポットライトを使用してください。一軸引張試験機の室に直接スポットを指します。 </li><li>それは、チャンバ内の試料の上面と平行になるようにカメラのレンズを調整し、ゲージ部にカメラの焦点を合わせます。 </li></ol> 5.実験プログラム<ol><li>制御ソフトウェアの三角形の実行]ボタンをクリックして、一軸引張試験機を抵抗加熱を実行します。 注：電気はAA6082材料を通して実行され、30℃/秒の加熱速度で535°C 14の溶体化処理温度までそれを加熱します。材料は、析出物の完全な解像度のために十分で1分間、535℃で浸漬されます。人工知能R急冷システムから吹いは370から510℃の範囲の100℃/秒15 3のいずれかに指定された高温の冷却速度で材料を急冷するために使用されます。 </li><li> 0.01 / sの範囲内の一定の歪み速度で二軸試験装置で試料を延伸し、手動で高速カメラに接続されたトリガボタンを押して変形履歴を記録します。 注：二軸試験装置に一軸試験機からの入力変位が一軸試験機の内蔵ソフトウェアによって制御しました。 </li><li>二軸試験装置の構成を調整することにより、異なる一軸からなる歪み経路、平面ひずみ、二軸ひずみ状態3で試験を行います。 <ol><li>一軸試験のための2つの対向する連結ロッドを外し。二軸試験装置上のドッグボーン試料をクランプし、ステップ3.1-3のように、溶接ケーブルに接続します。4.繰り返して、5.1から5.2を繰り返します。 </li><li>平面ひずみ状態で試験するための対応する方向に変形を制限するスクリューボルトとベースプレートに対向する二つのキャリッジを固定します。二軸試験装置上の十字片をクランプし、ステップ3.1から3.4のように、溶接ケーブルに接続します。繰り返しは、5.1から5.2を繰り返します。 </li></ol></li><li>繰り返しますが、新しい犬の骨と十字型の試験片を使用して、各試験条件について3回5.3.1-5.3.2を繰り返します。 </li></ol> 6.データ処理<ol><li>後処理ソフトウェアに高速度カメラによって記録されたすべての画像をインポートし、ソフトウェアのマニュアルに従って、データ分析のための標準手順に従います。 </li><li>ソフトウェアにおけるFLCモードボタンをクリックすることで形成限界を決定するためにISO標準3を使用してください。 注：このメソッドは、既に画像相関処理ソフトウェアに統合されています。 </li><li>種々の温度で形成限界の各結果をマーク図中のS、歪み率、および歪みのパス。 </li><li>ホットスタンピング条件下合金のFLDを得るために、全ての試験条件で成形限界曲線をプロットします。 </li></ol>

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The authors have nothing to disclose.

限界を形成するかを決定するために使用される従来の成形性の試験方法は、通常は室温で適用可能です。提示された技術は、一軸試験機を抵抗加熱するための新規な二軸試験装置を導入することにより、ホットシートスタンピングアプリケーションのための金属の成形性を評価するために使用することができます。これは、ホットスタンピングアプリケーションのための従来の方法を用いて?...

自動車業界は燃料消費量を削減し、自動車排出ガスによる環境汚染を最小限に抑えるの巨大なグローバルな課題に直面しています。軽量化は、自動車の性能向上に有益であると直接エネルギー消費量1を削減することができます。室温、ホットスタンプやコールドダイ急冷プロセス（ホットスタンピングと呼ばれる）2で金属薄板の低い成形性に合金の成形性を改善し、従って、自動車用途で複雑な形状の部品を得るために使用されます。 成形限界線図（FLD）が合金3の成形性を評価するための有用なツールです。面外ようNakazima試験4としてテスト、5、及びそのようなMarciniak試験6、7、8、Aと面内試験、様々な条件の下で9枚の金属のFLDを得るための従来の実験方法、10、11再。サーボ油圧式二軸試験機はまた、室温12、13における合金の成形性を調査するために使用されてきました。 成形前に、冷却工程は、加熱及び冷却速度の制御に伴って必要とされるので、上記の方法のいずれも、ホットスタンピング条件下で成形性の試験に適用されません。変形温度及び歪み速度を正確に得ることは困難です。したがって、新規な成形性試験システムは、実験的にホットスタンピング条件下で金属薄板の成形限界を決定するために、本研究で提案されています。

<table><tbody><tr><td>Aluminium Alloy&amp;nbsp;</td><td>Smiths Metal</td><td>6082</td><td>Specimens machining</td></tr><tr><td>Laser cutter</td><td>LVD Ltd</td><td>HELIUS 25/13</td><td>Laser cutting specimens</td></tr><tr><td>CNC machine</td><td>HAAS Automation</td><td>TM-2CE</td><td>Machine specimens by milling</td></tr><tr><td>Vernier caliper</td><td>Mitutoyo</td><td>575-481</td><td>Thickness measurement</td></tr><tr><td>Resistance heating uniaxial testing machine</td><td>Dynamic System Inc</td><td>Gleeble 3800</td><td>Thermo-mechanical materials simulator</td></tr><tr><td>High flow quench system</td><td>Dynamic System Inc</td><td>38510</td><td>For air cooling</td></tr><tr><td>Thermocouples</td><td>Dynamic System Inc</td><td>K type</td><td></td></tr><tr><td>Nozzles</td><td>Indexa</td><td></td><td>Nozzle flared 1/4 inch bore</td></tr><tr><td>Welding cables</td><td>LAPP Group</td><td>H01N2-D</td><td></td></tr><tr><td>High-speed camera</td><td>Photron</td><td>UX50</td><td>For DIC testing</td></tr><tr><td>Camera lens</td><td>Nikon</td><td>Micro 200mm</td><td></td></tr><tr><td>Lamp</td><td>Liliput</td><td>150ce</td><td>300 W</td></tr><tr><td>Laptop</td><td>HP</td><td>Campaq 2530p</td><td>For images recording</td></tr><tr><td>Biaxial testing apparatus</td><td>Manufactured independently</td><td></td><td>All parts were designed and machinced by authors for biaxial testing</td></tr><tr><td>Steel&amp;nbsp;</td><td>West Yorkshire Steel</td><td>H13</td><td>Mateials of the biaxial testing apparatus</td></tr><tr><td>Image correlation processing software</td><td>GOM</td><td>ARAMIS</td><td>Non-contact measuring system and data post-pocessing</td></tr></tbody></table>

a novel biaxial testing apparatus for the determination of forming limit under hot stamping conditions

ホットスタンプとコールドダイ急冷プロセスはますます板金の複雑な形状の構造要素を形成するために使用されます。このようなの面アウト面内テストなどの従来の実験的アプローチは、加熱及び急冷プロセスはホットスタンプ条件下で実施された試験のために形成する前に導入されたときに制限を形成する決意には適用できません。新規な面内二軸試験システムを設計し、一軸試験機を抵抗加熱の処理を加熱及び冷却後の様々なひずみ経路、温度、及び歪み速度でシート金属の限界を形成する決意のために使用しました。二軸試験システムのコア部分は、軸力を一軸試験機によって提供される一軸力を伝達する二軸装置、です。十字形試験片の1つのタイプは、提案された二軸試験システムを用いて、アルミニウム合金6082の成形性試験のために設計され、検証されました。デジタルイム高速度カメラと年齢相関（DIC）システムは、変形時に試験片のひずみ測定を行うために使用しました。この二軸試験システムを提案の目的は、ホットスタンピング条件下で、種々の温度及び歪み速度で決定される合金の成形限界を可能にすることです。

FLDが高いひずみ経路に依存しているので、各試験条件についてひずみ経路の直線性はDICの結果を分析することによって確認しました。ひずみ経路は各試験条件の変形を通して比例します。マイナー・ツー・主要なひずみ比の範囲は約-0.37（一軸条件）0.26（二軸延伸条件に近い）です。 、異なるAA6082条件のためのデータを処理する異なる歪みパスの制限データを形成?...

Watch this Scientific Journal Video about A Novel Biaxial Testing Apparatus for the Determination of Forming Limit under Hot Stamping Conditions at JoVE.com

A Novel Biaxial Testing Apparatus for the Determination of Forming Limit under Hot Stamping Conditions

このプロトコルは、ホットスタンピング条件下で金属薄板の成形限界線図（FLD）を決定するために、一軸引張試験機を抵抗加熱に使用される新規な二軸試験システムを提案しています。

ホットスタンプの条件の下で成形限界の決意のための新しい二軸試験機

The hot stamping and cold die quenching process is increasingly used to form complex shaped structural components of sheet metals. Conventional ...

a-novel-biaxial-testing-apparatus-for-determination-forming-limit

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7.5K ビュー.  Imperial College London. このプロトコルは、ホットスタンピング条件下で金属薄板の成形限界線図（FLD）を決定するために、一軸引張試験機を抵抗加熱に使用される新規な二軸試験システムを提案しています。 

ビデオ: A Novel Biaxial Testing Apparatus for the Determination of Forming Limit under Hot Stamping Conditions

High-pressure, High-temperature Deformation Experiment Using the New Generation Griggs-type Apparatus

In order to address geological processes at great depths, rock deformation should ideally be tested at high pressure (&#62; 0.5 GPa) and high temperature (&#62; 300 &#176;C). However, because of the low stress resolution of current solid-pressure-medium apparatuses, high-resolution measurements are today restricted to low-pressure deformation experiments in the gas-pressure-medium apparatus. A new generation of solid-medium piston-cylinder (&#34;Griggs-type&#34;) apparatus is here described. Able to perform high-pressure deformation experiments up to 5 GPa and designed to adapt an internal load cell, such a new apparatus offers the potential to establish a technological basis for high-pressure rheology. This paper provides video-based detailed documentation of the procedure (using the &#34;conventional&#34; solid-salt assembly) to perform high-pressure, high-temperature experiments with the newly designed Griggs-type apparatus. A representative result of a Carrara marble sample deformed at 700 &#176;C, 1.5 GPa and 10-5 s-1 with the new press is also given. The related stress-time curve illustrates all steps of a Griggs-type experiment, from increasing pressure and temperature to sample quenching when deformation is stopped. Together with future developments, the critical steps and limitations of the Griggs apparatus are then discussed.

Rock deformation needs to be quantified at high pressure. A description of the procedure to perform deformation experiments in a newly designed solid-medium Griggs-type apparatus is here given. This provides technological basis for future rheological studies at pressures up to 5 GPa.

新世代グリッグス型装置を使用して、高温高圧変形実験

In order to address geological processes at great depths, rock deformation should ideally be tested at high pressure (&#62; 0.5 GPa) and high temperature ...

環境学

Experimental Methods for Investigation of Shape Memory Based Elastocaloric Cooling Processes and Model Validation

Shape Memory Alloys (SMA) using elastocaloric cooling processes have the potential to be an environmentally friendly alternative to the conventional vapor compression based cooling process. Nickel-Titanium (Ni-Ti) based alloy systems, especially, show large elastocaloric effects. Furthermore, exhibit large latent heats which is a necessary material property for the development of an efficient solid-state based cooling process. A scientific test rig has been designed to investigate these processes and the elastocaloric effects in SMAs. The realized test rig enables independent control of an SMA&#39;s mechanical loading and unloading cycles, as well as conductive heat transfer between SMA cooling elements and a heat source/sink. The test rig is equipped with a comprehensive monitoring system capable of synchronized measurements of mechanical and thermal parameters. In addition to determining the process-dependent mechanical work, the system also enables measurement of thermal caloric aspects of the elastocaloric cooling effect through use of a high-performance infrared camera. This combination is of particular interest, because it allows illustrations of localization and rate effects &#8212; both important for efficient heat transfer from the medium to be cooled.
The work presented describes an experimental method to identify elastocaloric material properties in different materials and sample geometries. Furthermore, the test rig is used to investigate different cooling process variations. The introduced analysis methods enable a differentiated consideration of material, process and related boundary condition influences on the process efficiency. The comparison of the experimental data with the simulation results (of a thermomechanically coupled finite element model) allows for better understanding of the underlying physics of the elastocaloric effect. In addition, the experimental results, as well as the findings based on the simulation results, are used to improve the material properties.

Experimental methods for investigation of solid state cooling processes and characterization of elastocaloric material properties of Shape Memory Alloys (SMA) are presented. A custom-built test rig has been designed for controlling and comprehensive monitoring of elastocaloric cooling processes. Furthermore, it provides a validation platform for thermomechanically coupled modeling approaches.

形状記憶基づきElastocaloric冷却プロセスの調査とモデル検証のための実験方法

Shape Memory Alloys (SMA) using elastocaloric cooling processes have the potential to be an environmentally friendly alternative to the conventional vapor ...

工学

Knowledge Based Cloud FE Simulation of Sheet Metal Forming Processes

The use of Finite Element (FE) simulation software to adequately predict the outcome of sheet metal forming processes is crucial to enhancing the efficiency and lowering the development time of such processes, whilst reducing costs involved in trial-and-error prototyping. Recent focus on the substitution of steel components with aluminum alloy alternatives in the automotive and aerospace sectors has increased the need to simulate the forming behavior of such alloys for ever more complex component geometries. However these alloys, and in particular their high strength variants, exhibit limited formability at room temperature, and high temperature manufacturing technologies have been developed to form them. Consequently, advanced constitutive models are required to reflect the associated temperature and strain rate effects. Simulating such behavior is computationally very expensive using conventional FE simulation techniques.
This paper presents a novel Knowledge Based Cloud FE (KBC-FE) simulation technique that combines advanced material and friction models with conventional FE simulations in an efficient manner thus enhancing the capability of commercial simulation software packages. The application of these methods is demonstrated through two example case studies, namely: the prediction of a material's forming limit under hot stamping conditions, and the tool life prediction under multi-cycle loading conditions.

The following paper presents a novel FE simulation technique (KBC-FE), which reduces computational cost by performing simulations on a cloud computing environment, through the application of individual modules. Moreover, it establishes a seamless collaborative network between world leading scientists, enabling the integration of cutting edge knowledge modules into FE simulations.

シートメタル成形プロセスの知識ベースのクラウドFEシミュレーション

The use of Finite Element (FE) simulation software to adequately predict the outcome of sheet metal forming processes is crucial to enhancing the ...

Experimental Procedure for Warm Spinning of Cast Aluminum Components

High performance, cast aluminum automotive wheels are increasingly being incrementally formed via flow forming/metal spinning at elevated temperatures to improve material properties. With a wide array of processing parameters which can affect both the shape attained and resulting material properties, this type of processing is notoriously difficult to commission. A simplified, light-duty version of the process has been designed and implemented for full-size automotive wheels. The apparatus is intended to assist in understanding the deformation mechanisms and the material response to this type of processing. An experimental protocol has been developed to prepare for, and subsequently perform forming trials and is described for as-cast A356 wheel blanks. The thermal profile attained, along with instrumentation details are provided. Similitude with full-scale forming operations which impart significantly more deformation at faster rates is discussed.

An experimental protocol for instrumented warm rotary forming of cast aluminum alloys employing a bespoke industrially scaled apparatus is presented. Experimental considerations including thermal and mechanical effects are discussed, as well as similitude with full-scale processing of automotive wheels.

キャストアルミ部品の暖かいスピニングのための実験手順

High performance, cast aluminum automotive wheels are increasingly being incrementally formed via flow forming/metal spinning at elevated temperatures to ...

Ultrasonic Fatigue Testing in the Tension-Compression Mode

Ultrasonic fatigue testing is one of a few methods which allow investigating fatigue properties in the ultra-high cycle region. The method is based on exposing the specimen to longitudinal vibrations on its resonance frequency close to 20 kHz. With use of this method, it is possible to significantly decrease the time required for the test, when compared to conventional testing devices usually working at frequencies under 200 Hz. It is also used to simulate loading of material during operation in high speed conditions, such as those experienced by components of jet engines or car turbo pumps. It is necessary to operate only in the high and ultra-high cycle region, due to the possibility of extremely high deformation rates, which can have a significant influence on the test results. Specimen shape and dimensions have to be carefully selected and calculated to fulfill the resonance condition of the ultrasonic system; thus, it is not possible to test the full components or specimens of arbitrary shape. Before each test, it is necessary to harmonize the specimen with the frequency of the ultrasonic system to compensate for deviations of the real shape from the ideal one. It is not possible to run a test until a total fracture of the specimen, since the test is automatically terminated after initiation and propagation of the crack to a certain length, when the stiffness of the system changes enough to shift the system out of the resonance frequency. This manuscript describes the process of evaluation of materials' fatigue properties at high-frequency ultrasonic fatigue loading with use of mechanical resonance at a frequency close to 20 kHz. The protocol includes a detailed description of all steps required for a correct test, including specimen design, stress calculation, harmonizing with the resonance frequency, performing the test, and final static fracture.

A protocol for ultrasonic fatigue testing in the high and ultra-high cycle region in axial tension-compression loading mode.

超音波疲労引張圧縮モードでのテスト

Ultrasonic fatigue testing is one of a few methods which allow investigating fatigue properties in the ultra-high cycle region. The method is based on ...

Conducting Elevated Temperature Normal and Combined Pressure-Shear Plate Impact Experiments Via a Breech-end Sabot Heater System

A novel approach for conducting normal and/or combined pressure-shear plate impact experiments at test temperatures up to 1000 &#176;C is presented. The method enables elevated temperature plate-impact experiments aimed towards probing dynamic behavior of materials under thermomechanical extremes, while mitigating several special experimental challenges faced while performing similar experiments using the conventional plate impact approach. Custom adaptations are made to the breech-end of a single-stage gas-gun at Case Western Reserve University; these adaptations include a precision-machined extension piece made from SAE 4340 steel, which is strategically designed to mate the existing gun-barrel while providing a high tolerance match to the bore and keyway. The extension piece contains a vertical cylindrical heater-well, which houses a heater assembly. A resistive coil heater-head, capable of reaching temperatures of up 1200 &#176;C, is attached to a vertical stem with axial/rotational degrees of freedoms; this enables thin metal specimens held at the front-end of a heat-resistant sabot to be heated uniformly across the diameter to the desired test temperatures. By heating the flyer plate (in this case, the sample) at the breech-end of the gun-barrel instead of at the target-end, several critical experimental challenges can be averted. These include: 1) severe changes in the alignment of the target plate during heating due to the thermal expansion of the several constituents of the target holder assembly; 2) challenges that arise due to the diagnostics elements, (i.e., polymer holographic gratings, and optical probes) being too close to the heated target assembly; 3) challenges that arise for target plates with an optical window, where crucial tolerances between the sample, bond layer, and window become increasingly difficult to maintain at high temperatures; 4) in the case of combined compression-shear plate impact experiments, the need for high-temperature resistant diffraction gratings for the measurement of transverse particle velocity at the free surface of the target; and 5) limitations imposed on the impact velocity necessary for unambiguous interpretation of the measured free surface velocity versus time profile due to thermal softening and possibly yielding of the bounding target plates.By utilizing the adaptations mentioned above, we present results from a series of reverse geometry normal plate impact experiments on commercial purity aluminum at a range of sample temperatures. These experiments show decreasing particle velocities in the impacted state, which are indicative of material softening (decrease in post-yield flow stress) with increasing sample temperatures.

Here, we present a detailed protocol of a new approach for conducting elevated temperature reverse normal plate impact, and combined pressure-and-shear plate impact. The approach involves the use of a breech-end resistive coil heater to heat a sample held at the front-end of a heat-resistant sabot to the desired temperature.

通常の温度の上昇を実施し、尾端サボ ヒーター システムを介して圧力剪断平板衝突試験を組み合わせる

A novel approach for conducting normal and/or combined pressure-shear plate impact experiments at test temperatures up to 1000 &#176;C is presented. The ...

Application of Design Aspects in Uniaxial Loading Machine Development

In terms of accurate and precise mechanical testing, machines run the continuum. Whereas commercial platforms offer excellent accuracy, they can be cost-prohibitive, often priced in the $100,000 - $200,000 price range. At the other extreme are stand-alone manual devices that often lack repeatability and accuracy (e.g., a manual crank device). However, if a single use is indicated, it is over-engineering to design and machine something overly elaborate. Nonetheless, there are occasions where machines are designed and built in-house to accomplish a motion not attainable with the existing machines in the laboratory. Described in detail here is one such device. It is a loading platform that enables pure uniaxial loading. Standard loading machines typically are biaxial in that linear loading occurs along the axis and rotary loading occurs about the axis. During testing with these machines, a load is applied to one end of the specimen while the other end remains fixed. These systems are not capable of conducting pure axial testing in which tension/compression is applied equally to the specimen ends. The platform developed in this paper enables the equal and opposite loading of specimens. While it can be used for compression, here the focus is on its use in pure tensile loading. The device incorporates commercial load cells and actuators (movers) and, as is the case with machines built in-house, a frame is machined to hold the commercial parts and fixtures for testing.

Here we present a protocol to develop a pure uniaxial loading machine. Critical design aspects are employed to ensure accurate and reproducible testing results.

一軸荷重マシン開発のデザイン面のアプリケーション

In terms of accurate and precise mechanical testing, machines run the continuum. Whereas commercial platforms offer excellent accuracy, they can be ...

Biaxial Mechanical Characterizations of Atrioventricular Heart Valves

Extensive biaxial mechanical testing of the atrioventricular heart valve leaflets can be utilized to derive&#160;optimal parameters used in constitutive models, which provide a mathematical representation of the mechanical function of those structures. This presented biaxial mechanical testing protocol involves (i) tissue acquisition, (ii) the preparation of tissue specimens, (iii) biaxial mechanical testing, and (iv) postprocessing of the acquired data. First, tissue acquisition requires obtaining porcine or ovine hearts from a local Food and Drug Administration-approved abattoir for later dissection to retrieve the valve leaflets. Second, tissue preparation requires using tissue specimen cutters on the leaflet tissue to extract a clear zone for testing. Third, biaxial mechanical testing of the leaflet specimen requires the use of a commercial biaxial mechanical tester, which consists of force-controlled, displacement-controlled, and stress-relaxation testing protocols to characterize the leaflet tissue&#39;s mechanical properties. Finally, post-processing requires the use of data image correlation techniques and force and displacement readings to summarize the tissue&#39;s mechanical behaviors in response to external loading. In general, results from biaxial testing demonstrate that the leaflet tissues yield a nonlinear, anisotropic mechanical response. The presented biaxial testing procedure is advantageous to other methods since the method presented here allows for a more comprehensive characterization of the valve leaflet tissue under one unified testing scheme, as opposed to separate testing protocols on different tissue specimens. The proposed testing method has its limitations in that shear stress is potentially present in the tissue sample. However, any potential shear is presumed negligible.

This protocol involves characterizations of atrioventricular valve leaflets with force-controlled, displacement-controlled, and stress-relaxation biaxial mechanical testing procedures. Results acquired with this protocol can be used for constitutive model development to simulate the mechanical behavior of functioning valves under a finite element simulation framework.

房室弁の二軸の機械特性

Extensive biaxial mechanical testing of the atrioventricular heart valve leaflets can be utilized to derive&#160;optimal parameters used in constitutive ...

生物工学

Layer Microdissection of Tricuspid Valve Leaflets for Biaxial Mechanical Characterization and Microstructural Quantification

The tricuspid valve (TV) regulates the unidirectional flow of unoxygenated blood from the right atrium to the right ventricle. The TV consists of three leaflets, each with unique mechanical behaviors. These variations among the three TV leaflets can be further understood by examining their four anatomical layers, which are the atrialis (A), spongiosa (S), fibrosa (F), and ventricularis (V). While these layers are present in all three TV leaflets, there are differences in their thicknesses and microstructural constituents that further influence their respective mechanical behaviors. 
This protocol includes four steps to elucidate the layer-specific differences: (i) characterize the mechanical and collagen fiber architectural behaviors of the intact TV leaflet, (ii) separate the composite layers (A/S and F/V) of the TV leaflet, (iii) carry out the same characterizations for the composite layers, and (iv) perform post-hoc histology assessment. This experimental framework uniquely allows the direct comparison of the intact TV tissue to each of its composite layers. As a result, detailed information regarding the microstructure and biomechanical function of the TV leaflets can be collected with this protocol. Such information can potentially be used to develop TV computational models that seek to provide guidance for the clinical treatment of TV disease.

This protocol describes the biaxial mechanical characterization, polarized spatial frequency domain imaging-based collagen quantification, and microdissection of tricuspid valve leaflets. The provided method elucidates how the leaflet layers contribute to the holistic leaflet behaviors.

二軸の機械的特性評価と微細構造定量化のための三尖弁リーフレットの層マイクロダイセクション

The tricuspid valve (TV) regulates the unidirectional flow of unoxygenated blood from the right atrium to the right ventricle. The TV consists of three ...

Stress-Strain Characteristics of Steels

Source:&#160;Roberto Leon, Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA
The importance of materials to human development is clearly captured by the early classifications of world history into periods such as the Stone Age, Iron Age, and the Bronze Age. The introduction of the Siemens and Bessemer processes to produce steels in the mid-1800s is arguably the single most important development in launching the Industrial Revolution that transformed much of Europe and the USA in the second half of the 19th century from agrarian societies into the urban and mechanized societies of today. Steel, in its almost infinite variations, is all around us, from our kitchen appliances to cars, to lifelines such as electrical transmission networks and water distribution systems. In this experiment we will look at the stress-strain behavior of two types of steel that bound the range usually seen in civil engineering applications - from a very mild, hot rolled steel to a hard, cold rolled one.

ホットスタンプの条件の下で成形限界の決意のための新しい二軸試験機

要約

さらに動画を探す

この動画の章

新世代グリッグス型装置を使用して、高温高圧変形実験

形状記憶基づきElastocaloric冷却プロセスの調査とモデル検証のための実験方法

シートメタル成形プロセスの知識ベースのクラウドFEシミュレーション

キャストアルミ部品の暖かいスピニングのための実験手順

超音波疲労引張圧縮モードでのテスト

通常の温度の上昇を実施し、尾端サボヒーターシステムを介して圧力剪断平板衝突試験を組み合わせる

一軸荷重マシン開発のデザイン面のアプリケーション

房室弁の二軸の機械特性

二軸の機械的特性評価と微細構造定量化のための三尖弁リーフレットの層マイクロダイセクション

鋼の応力-ひずみ特性

ホットスタンプの条件の下で成形限界の決意のための新しい二軸試験機

要約

さらに動画を探す

この動画の章

新世代グリッグス型装置を使用して、高温高圧変形実験

形状記憶基づきElastocaloric冷却プロセスの調査とモデル検証のための実験方法

シートメタル成形プロセスの知識ベースのクラウドFEシミュレーション

キャストアルミ部品の暖かいスピニングのための実験手順

超音波疲労引張圧縮モードでのテスト

通常の温度の上昇を実施し、尾端サボ ヒーター システムを介して圧力剪断平板衝突試験を組み合わせる

一軸荷重マシン開発のデザイン面のアプリケーション

房室弁の二軸の機械特性

二軸の機械的特性評価と微細構造定量化のための三尖弁リーフレットの層マイクロダイセクション

鋼の応力-ひずみ特性

通常の温度の上昇を実施し、尾端サボヒーターシステムを介して圧力剪断平板衝突試験を組み合わせる