實時全場測量技術(shù)，10Hz采樣頻率下高達10,000個數(shù)據(jù)點的實時數(shù)據(jù)云圖監(jiān)測

Real-Time Full-Field Strain Measurements, up to 10,000 data points at 10Hz

全場實時測量的應(yīng)用價值 What are the benefits of full-field real-time measurements?

作為DIC數(shù)字圖像相關(guān)測量技術(shù)領(lǐng)域企業(yè)，Correlated Solutions, Inc.開發(fā)出了市場上率的數(shù)字圖像處理算法，從而實現(xiàn)了的3D處理速度。 當需要快速分析高密度圖像采集序列時，該高效算法尤為重要。

As the world-leader in digital image correlation, Correlated Solutions has developed the most efficient digital image processing algorithms that are commercially available, resulting in the fastest 3D processing speeds available. Our highly efficient algorithms are particularly important when high density image acquisition sequences need to be analyzed very quickly.

由Correlated Solutions，Inc.提供的VIC-3D實時處理模塊允許全場測試數(shù)據(jù)在測試運行時同步顯示。 Vic-3D實時模塊可以為用戶提供在測試過程中執(zhí)行試驗關(guān)鍵參數(shù)調(diào)整所需的信息，以確保實驗按用戶預(yù)期的方式進行加載。 進行非常昂貴或生產(chǎn)的數(shù)量有限的試件測試時，這是價值的監(jiān)測工具 。該模塊可同時配合VIC-Snap™進行圖像采集保存和無縫同步外部模擬數(shù)據(jù), 方便后處理時分析獲取更密集的數(shù)據(jù)點集。

The VIC-3D Real-Time Processing Module by Correlated Solutions, Inc. allows full-field test data to be displayed live while a test is running. The Vic-3D Real-Time Module can provide users with information needed to make critical adjustments during the test, ensuring the loading is applied as expected. The module proves to be especially valuable when monitoring specimens that are either very expensive and/or have been produced in a limited quantity. Image acquisition via Vic-Snap is performed concurrently with seamless external analog data synchronization for post-processing images to create denser data sets.

通過這個模塊，用戶可以自由選擇2-10 Hz的處理速率（高達100,000個數(shù)據(jù)點/秒）的數(shù)據(jù)密度。 實時數(shù)據(jù)顯示在用戶的無限數(shù)量的3D圖、2D輪廓圖疊加和橫截面圖中。 即使您選擇不使用實時模塊，也可以使用我們的系統(tǒng)更高效地執(zhí)行您的工作。 考慮一個包含150個圖像的測試序列，每個圖像包含200,000個待測量的數(shù)據(jù)點。 使用Vic-3D，可以在標準i7單CPU計算機上僅用5分鐘處理完成整個序列。 而其他傳統(tǒng)的數(shù)字圖像相關(guān)系統(tǒng)可能需要大約1小時才能在同一臺計算機上完成處理相同的數(shù)據(jù)。

With this module users can freely choose the data density for processing rates of 2-10 Hz (up to 100,000 data points/second). Live data is displayed in an unlimited number of user specified 3D plots, 2D contour image overlays, and cross-sectional graphs. Even if you choose not to use the Real-Time module, your work can be carried out much more efficiently using our systems. Consider a test sequence of 150 images, each of which contains 200,000 data points to be measured. With Vic-3D, this entire sequence can be processed in just over 5 minutes on a standard i7 single CPU computer. Other conventional digital image correlation system would likely require approximately 1 hour to process the same data on the same computer.

該模塊還兼容VIC-Gauge 3D，它允許用戶保存圖像并記錄來自虛擬應(yīng)變儀或引伸計的數(shù)據(jù)，這些數(shù)據(jù)可以通過附帶的DAQ系統(tǒng)以高達250Hz的頻率實時導(dǎo)出為等比電壓。 只需設(shè)置電壓比例系數(shù)（例如E1 1％= 1V），則系統(tǒng)就可以作為測試的控制傳感器操作。

This module is also compatible with VIC-Gauge 3D, which allows the user to save images and record data from virtual strain gauges or extensometers, which are exported as a scaled voltage via the included DAQ system in real time up to 250Hz. Simply set the voltage scaling (e.g. E1 1% = 1V), and now the system can operate as a controlling sensor for the test.

據(jù)我們所知，市場上沒有任何其他DIC系統(tǒng)能夠以這樣的速度完成實時測量。

To our knowledge, there is no other DIC system on the market that can accomplish real-time measurements at these speeds.

應(yīng)用案例 Application Example

壓扁“汽水罐”也是火箭科學(xué) Crushing “Cans” Is Rocket Science

對于我們大多數(shù)人來說，壓扁鋁罐是一個熟悉的場景。 但是，如果你不得不精確地模擬一個罐子的擠壓負荷呢？ 而且，如果這個“罐”是一個直徑27.5英尺的復(fù)雜結(jié)構(gòu)呢？ 這就是NASA工程師面臨的挑戰(zhàn)。

For most of us, the crushing of aluminum cans is a familiar scene.  But, what if you had to precisely model the crush load of a can?  And, what if the “can” was a complex structure with a diameter of 27.5 feet?  This was the challenge facing NASA engineers.

圓柱形火箭外殼的負載類似于汽水罐。 它們在提升載荷下的強度被稱為“殼體屈曲失穩(wěn)因子”或SBKF。 原始的SBKF模型是在20世紀60年代開發(fā)的。 當時可用的技術(shù)選擇限制了這些模型的準確性。 其結(jié)果是，火箭的設(shè)計必須是過度設(shè)計的安全性，并且增加了大量不必要的重量。

Cylindrical rocket shells are subject to loads similar to soda cans.  Their strength under lifting loads is referred to as a “Shell Buckling Knockdown Factor” or SBKF.   The original SBKF models were developed back in the 1960’s.  The available technology of the era limited the accuracy of these models.   As a result, rocket designs had to be over-engineered for safety, and were unnecessarily heavy.

今天，諸如有限元建模等技術(shù)允許分析更詳細的模型。 但是，這些模型必須通過對真實試件的測試來驗證。 實際試件在載荷下的位移是驗證過程的關(guān)鍵部分，當涉及到這些數(shù)據(jù)時，實驗數(shù)據(jù)更好。

Today, technologies such as Finite Element Modeling permit more detailed models.  But, these models must be validated through the testing of real specimens.   Actual specimen displacements under load are a critical part of the validation process, and when it comes to this data, more is definitely better.

美國宇航局NASA啟動了一個SBKF模型的升級計劃。 2011年3月23日，NASA成功進行了一個全尺寸試件失效測試，這是一個重要的里程碑。 該測試在互聯(lián)網(wǎng)上直播，并存檔在www.ustream.tv（NASA電視頻道：World’s Largest Can Crusher）。

NASA started a program to update their SBKF models.  An important milestone was reached on March 23, 2011, when NASA successfully tested a full-scale specimen to failure.  This test was broadcast live on the internet, and is archived at www.ustream.tv (NASAtelevision: World’s Largest Can Crusher).

為了獲得他們所需的位移數(shù)據(jù)的數(shù)量和質(zhì)量，NASA選擇Correlated Solutions, Inc提供的3D數(shù)字圖像相關(guān)（DIC）系統(tǒng)實現(xiàn)。將隨機黑白散斑圖案應(yīng)用于試件表面（見照片右側(cè)并注意參照試件下面的移動升降機的尺寸）。 圖像采集器連續(xù)監(jiān)測樣品的整個表面，VIC-3D軟件允許NASA工程師實時監(jiān)測詳細的全場三維位移和應(yīng)變數(shù)據(jù)！ 共有7個VIC-3D系統(tǒng)用于覆蓋整個360度的區(qū)域。

To get the quantity and quality of displacement data they would need, NASA relied on 3D Digital Image Correlation (DIC) systems supplied by Correlated Solutions, Inc.  Random black-and-white patterns were applied to the surface of the specimen (see photo right and note the size of the lift below the specimen).  Digital cameras continuously monitored the entire surface of the specimen, and VIC-3D software allowed NASA engineers to monitor detailed full-field three-dimensional displacement and strain data in real-time!  A total of seven systems were used to cover the entire 360 degree area.

實驗中樣品被加壓至1psi并逐漸加載至超過800,000磅。 雖然外壁光滑，但內(nèi)部肋和焊縫所受的影響可以在離面位移數(shù)據(jù)w或Δz中清楚地看到（見左圖）。 正如視頻中的一位NASA測試工程師所說：“這是我們在測試過程中觀察到的實時數(shù)據(jù)類型，因此我們確切的知道正在發(fā)生什么。”

The specimen was pressurized to 1psi and gradually loaded to more than 800,000 pounds.  Although the outer wall was smooth, the effects of internal ribs and welds can be plainly seen in the out-of-plane displacement data w or Δz (see image left).    As one NASA test engineer in the video feed put it: “this is the type of real time data we get to observe during the test so we know exactly what’s going on.”

實時的VIC-3D數(shù)據(jù)也被用于監(jiān)測和控制測試過程。 高速攝像機在破壞發(fā)生時以每秒3,000幀的速度捕獲圖像，并且所有同步記錄的視頻圖像都被保存了。 因此，美國國家航空NASA的工程師可以在整個測試周期內(nèi)獲得試件的詳細的全場3D變形測量。

The real-time VIC-3D data was used to monitor and control the testing process.  High-Speed cameras captured images at 3,000 frames per second at the moment of failure.  And, all of the synchronized video images were saved.   As a result, NASA engineers have access to detailed, full-field, 3D deformation measurements of the specimen, throughout the entire test cycle.

DIC數(shù)字圖像相關(guān)技術(shù)在美國宇航局SBKF測試計劃中發(fā)揮了關(guān)鍵性作用。 正如視頻所顯示的那樣，VIC-3D系統(tǒng)提供的信息是任何其他技術(shù)都難以想象的。 與有限元分析建模結(jié)合使用，它將使NASA為未來的火箭減輕重量并增加有效載荷。

Digital Image Correlation has played a key role in the successful NASA SBKF test program.  As the video footage shows, the VIC-3D system provides information that would be unimaginable with any other technology.  Used in conjunction with FEA modeling, it will allow NASA to decrease weight and increase the payload of future rockets.

照片由NASA公眾推廣網(wǎng)站提供 Photos courtesy of NASA public outreach site: www.nasa.gov/topics/technology/features/buckling2.html