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µTS: Micro Test System
受限于可见光波长的衍射极限，光学显微镜分辨率只能达到250nm。而数字图像相关(DIC)技术，则是一种可达到0.1像素位移解析度的功能强大的图像后处理技术。两相结合可获得可见光条件下的分辨率为25nm的2D全场位移数据。通过这种方式，可以在不需要AFM或SEM的情况下进行纳米长度尺度研究。此外，还可发挥光学显微镜快速图像采集的优势。 The wavelength of visible light limits optical microscope resolution to 250 nm. Digital Image Correlation (DIC) is a powerful post-processing technique for resolving feature displacements down to 0.1 pixels. Combining DIC and optical microscopes gives 25 nm resolution of the full 2D displacement field. In this way, nano length scale research can be conducted without the need for an AFM or SEM. Moreover, optical microscopy offers the advantage of fast image acquisition.
在光学显微镜下进行材料原位试验的主要挑战是试件的离面运动。要实现25nm位移场分辨率所需的高放大率也意味着景深会很小。几微米的离面运动也足以导致图像失焦。Psylotech的μTS独特的结构设计专门用于限制试验过程中试件的离面位移。使得这一精密仪器非常适合于以下应用：
The primary challenge with in situ materials testing under optical microscopes is out-of-plane specimen deflection. The high magnifications needed to achieve 25 nm displacement field resolution also mean a small depth of field. A few microns out-of-plane motion causes the image to go out of focus. Psylotech's µTS is specifically designed to keep a sample in- plane during testing. The result is a sophisticated instrument well suited for:
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• 连续模型，通过多尺度试验进行有限元分析验证
• 微型试件测试，用以促进材料开发，而所需试件样本数量可以很少
• 前所未有的多功能性，可用于实现新的实验技术测试
• Continuum Model Validation of finite element analysis through multi-scale testing
• Miniature Sample Testing to facilitate material development where quantities can be low
• Unprecedented Versatility to enable implementation of new experimental techniques testing
连续模型验证 Continuum Model Validation
在有限元分析(FEA)中，为实现合理的计算时间，通过假定材料的机械性能是均匀的，用以限制单元的尺寸。Psylotech的μTS是一种可跨越6个尺度量级的验证连续模型工具。通过数字图像相关(DIC)和优化的显微镜光学系统，可在力学性能测试过程保持全场位移分辨率低至0.1像素。这意味着位移场中的分辨率高达25 nm，应变场中的分辨率高达0.01％。
以一个复材铺层为例。 通常，FEA假定均匀的各向异性材料行为。 在给定的铺层测试中必须在多个方向上通过实验确定。 如果铺层被修改或基质材料被改变时，应该进行新的测试以重新定义材料特性。 多尺度试验提供了一种工具，可以更好地理解纤维之间以及纤维和基质之间的相互作用。 通过更小尺度的测试数据，可以对任何分层的连续属性进行建模，跳过额外的实验步骤并加快组件开发时间。 此外，更好地理解小尺度相互作用和小尺度失效机制可以从根本上改善材料性能。。
In finite element analysis (FEA), material mechanical properties are presumed uniform to limit the size of elements for reasonable computation times. Psylotech's µTS is a tool to validate continuum models over 6 length scales. Through digital image correlation (DIC) and optimized microscope optics, the full displacement field can be monitored down to 0.1 pixel resolution during a mechanical test. This means up to 25 nm resolution in the displacement field and 0.01% resolution in the strain field, depending on camera resolution.
Consider the example of a composite layup. Typically, FEA presumes uniform, anisotropic material behavior. Tests on a given layup must be experimentally determined in multiple directions. If the layup is modified or the matrix material is changed, new tests should be conducted to re-define material properties. Multi-scale testing offers a vehicle to better understand the interaction between fibers as well as between fibers and the matrix. With test data on smaller scales, continuum properties for any layup can be modeled, skipping an extra experimentation step and accelerating component development time. Moreover, better understanding of small scale interactions and small scale failure mechanisms can lead to fundamentally improved materials.
微型样品测试 Miniature Sample Testing
在新材料研究和开发中，样品产量可能太小，无法生产出符合STM标准的全尺寸，加之纳米颗粒增强复合材料的高成本问题。假设需要五个样品进行测试以产生统计相关数据，最终机加工的狗骨试件可能会被证明所需成本过高。而通过结合DIC的局部应变测量，µTS可以在更小的样品上执行精确的测试，从而在可用于测试的材料较少时提供同样高质量的数据。
In novel materials research and development, sample yields can be too small to produce full scale ASTM samples. Consider the case of high cost nano-particle reinforced composites. Presuming five specimens are tested to produce statistically relevant data, machined dog-bone samples could prove cost prohibitive. With local strain measurement from the DIC, The µTS can perform accurate tests on significantly smaller samples, offering quality data when less material is available for testing.
前所未有的多功能性 Unprecedented Versatility
Psylotech的µTS系统所具有的广泛的应用功能，将其与目前市场上的任何其他显微镜下的系统区分开来。除了新的实验技术外，这些特性为材料测试应用提供了新的可能性。其中包括：
Psylotech's µTS includes a wide range of features which separate it from any other under-microscope system currently on the market today. These features allow for new possibilities in material testing applications in addition to novel experimental techniques. Some of them include:
1. 丰富的夹具类型 Large Grip Variety
作为一种通用的通用测试系统，µTS可以进行多种力学性能测试。夹具选项包括：Arcan、拉伸、薄膜拉伸、压缩、弯曲等。这些夹具还适用于断裂力学测试。
As a versatile universal testing system, the µTS accommodates many mechanical tests. Grip options include: Arcan, tension, film tension, compression and beam bending. These grips also accommodate fracture mechanics testing.
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2. 滚珠丝杠伺服作动器 Ball Screw Servo Actuator A low friction, direct drive, ball screw actuator facilitates precision motion control, compared to lead screw actuators and covers 8 orders of magnitude in speed. With peak speed performance approaching a standard servohydraulic universal test frame, the µTS is effective for step-load and load control experiments. The system can also operate in cross-head displacement control or motor drive shaft position control. |
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3. 高分辨率载荷传感器 High Resolution Load Cell 与应变式传感器相比，Psylotech 使用具有更高灵敏度的电容式双量程载荷传感器。凭借更高的灵敏度和信噪比，独有的传感器技术将分辨率提高了 100 倍，因此 1600 N 单元可以提供亚 mN级分辨率。高分辨率减少了为小力值测试安装较小范围载荷传感器的必要性。该载荷传感器可提高实验室效率，消除安装和载荷系重新调整所需的时间。 Psylotech uses a capacitive dual range load cell with higher sensitivity compared to strain gauged sensors. With higher sensitivity and a similar signal to noise ratio, the proprietary sensor technology has 100x higher resolution such that a 1600 N cell can offer sub-mN resolution. High resolution reduces the need to install smaller range load cells for low force tests. Keeping the load cell installed improves lab efficiency, eliminating installation and load train realignment time. |
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4. 高分辨率十字头位移传感器 High Resolution Cross-head Displacement Sensor Psylotech uses an inductive displacement sensor for measuring local strains directly at the cross-head. With a range of 25 mm and resolution of 25 nm, this tool allows for very small, controlled moves as close to the specimen as possible. The support posts on either side of the system can be adjusted depending on the gauge length of the specimen. Custom post lengths available upon request. |
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5. X向补偿台选配 X-Stage Option n available X-Stage option makes it possible to keep the area of interest centered within the field of view of the microscope objective throughout the test. This is achieved via the control software which slaves the X- Stage to the moving cross-head by a user adjustable ratio. The µTS mounts directly on top of the X-Stage, all mounting hardware included. The X-Stage is capable of covering the full primary stage travel. |
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6. LabVIEW控制软件 Control Software 秉承为实验人员提供开发新技术工具的主旨，Psylotech为用户提供了对LabVIEW源代码的访问功能，包括闭环控制。高级用户可以自行编程调整以满足他们的特定需求或个人喜好。 Keeping with the theme of giving experimentalists a tool to develop new techniques, Psylotech offers the user access to the LabVIEW source code, including the closed loop control. Advanced users can make adjustments to suit their specific needs or personal preference. |
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7. 温度环境腔 Temperature Chamber 通过与光学显微镜兼容的温度控制模组可加速热机械模型的验证。该试验箱允许进行-100℃至+200℃的试验时同步精确的DIC、载荷值和十字头位移值测量。稳定性优于0.5℃，并能够在几分钟内通过快速线性的温度调整实现整个温度范围的涵盖。低温试验通过液氮连接与高流速鼓风机集成，可确保试样周围温度分布均匀。 Validating thermomechanical models is accelerated with an optical microscope compatible temperature control module. The chamber allows -100C to +200C tests with precise and accurate DIC, load and cross-head displacement measurements. Stability is better than .5C and fast ramp speeds cover the entire temperature range in minutes. Liquid nitrogen hookups are integrated with a high flow rate blower that ensures even temperature distribution around the specimen. |
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| 性能参数 Specifications | ||||
| 最大试验力 Force Capacity | 100N | 1.6kN | 4.5kN (SEM) | 10kN |
| 力分辨率 High Res. Resolution | 50µN | 800µN | 2.5mN | 5mN |
| 行程 Stroke (mm) | 27 | 40 | 23 | 100 |
| 定位控制精度 Positioning Control (nm) | <5 | <5 | <5 | <25 |
| 最小位移加载速率 Minimum Rate (nm/s) | 12 | 12 | 3 | 60 |
| 最大位移加载速率 Maximum Rate (mm/s) | 160 | 160 | 40 | 100 |
| 位移峰值加速度 Peak Acceleration (m/s²) | 10 | 10 | 0.6 | 7 |
| 主机尺寸 Envelope L×W×H (mm) | 220×100×54 | 300×100×54 | 180×100×71 | 650×200×123 |
| 自重 Mass (kg) | 1.3 - 2.2 | 1.5 - 2.5 | 1.5 | 23 |
| 闭环控制频率 Control Loop (Hz) | 1.6MHz(电流), 16KHz(速度), 8KHz(定位), 500Hz (输出) | |||
| 电源 Power Requirement | 120/240V@50/60Hz | |||
