“Meso is the new nano.” - Prof.Peter Hosemann, UC Berkeley
µTS – Meso Scale Under Microscope Universal Load Frame
Psylotech’s µTS is a miniature universal material test system uniquely capable on length scales between nano-indenters and macro universal load frames. Non-contact, local strain measurement on these so-called meso length scales comes from digital image correlation (DIC) and microscopy.
• Length: Constraining out-of-plane motion, the µTS enables effective high magnification digital image correlation, despite depth-of-field limitations in the optical microscopes.
• Speed: The direct-drive ballscrew actuator enables speeds covering 9 orders of magnitude. High speed enables effective load control, rate dependent studies and creep or stress relaxation tests.
• Force: Proprietary ultra high resolution sensor technology provides 100x higher resolution compared to strain gaged alternatives.
即刻下载并查阅µTS产品彩页 Download µTS Brochure (2018.09.06更新版).
作为通用测试系统，μTS为不同类型的夹具配备了T型槽接口。 三角形/平面界面几何形状确保精确的旋转对齐。可用的标准夹具包括拉伸、压缩、梁弯曲和混合模式Arcan。 并可根据您的特定需求设计定制夹具。
As a universal test system, the µTS implements a T-slot interface for different kinds of grips. The triangle/flat interface geometry ensures accurate rotational alignment. Available standard grips include tension, compression, beam bending and mixed-mode Arcan. Ask us how custom grips can be designed for your specific needs.
在其顶部和底部表面上夹紧试件可能导致在加载期间的离面运动。 环绕拉伸夹具可将样品保持在垂直于观察平面的表面上，并且有效地将样品保持在平面内。 另外一个好处是，样品可以非常快速地安装在环绕式夹具中。
Clamping a specimen on its top and bottom surfaces can lead to out of plane motion during loading. The wrap around tension grips hold the sample on surfaces perpendicular to the observation plane and have been effective in keeping the specimen in plane. As an added benefit, specimens can be very quickly mounted in the wrap around grips.
Some materials, like film or chopped fiber composites, are not conducive to the wrap-around grip geometry. Clamping grips can be used in these cases. A vertical micrometer screw adjustment can compensate causes out of plane motion. Also, a single clamping screw eliminates asymmetric clamping torque.
The Arcan grip geometry enables mixed-mode loading from a uniaxial load frame. Rotating the grips controls the ratio of pure shear to pure axial strain. This technique takes full advantage of local strain measurement via digital image correlation.
The compression platens implement a lightly sprung shelf to hold the sample before load is applied. Under load, the light spring easily deforms as the specimen expands
Three and Four point bending fixtures are available. All but one contact point is on a hardened steel roller. The fixed contact point prevents translation, which can give false compliance readings when using compliance to monitor crack growth. Both 3- and 4-point fixtures implement the same lightly sprung shelf as the compression platens.
The modularity of the µTS is as flexible as it is powerful. Below are some of the easily configured options.
Low Force Load Cell: 100N version of the 1.6 kN load cell provides finer force resolution. Ask us about force resolution down to 100 nano Newtons.
Increased Speed: A higher pitch ball-screw, increased motor stack, or higher input voltage can produce speeds up to 250 mm/sec, up from the 80 mm/sec of the stock system.
Extended Stoke: The 40mm stock instrument stroke can be extended substantially, depending on experimental need.
Environmental Chamber: Temperatures between -100C and 200C can be controlled via the optional environmental chamber. Higher temperatures are also available. Low temperatures require liquid nitrogen.
SEM: The µTS can be vacuum hardened for use in scanning electron microscopes. Please note, rastering time as well as spacial and temporal drift complicate DIC with SEM images. Optical microscopy does not have these limitations.
Centering X-stage: A secondary positioning stage keeps any specimen inside the microscope field of view, regardless of the amount of deformation.
Samplified Displacement Sensor: As a cost saving measure, the rotary encoder and ball screw pitch can be used to infer displacements in lieu of the high resolution local displacement sensor.
Sub-10nm Positioning: With a 22 bit rotary encoder mounted to the motor, a 1mm pitch ball screw gives ~238 picometers of linear resolution. Noise of the sensor and tuning jitter bring the closed loop error to under 10nm linearly.
Complete Turnkey Package: Psylotech can provide a complete DIC package, including an Olympus BXFM boom-mounted microscope, Correlated Solutions Vic2D software, a vibration isolation table and a 4 MP USB3.0 camera.
Confocal Raman Microscope: Psylotech’s µTS has been integrated into a Witec confocal Raman microscope. The Psylotest control software controls the microscope stage for specimen centering.
Tension-Torsion Actuator: An extra motor is added to the fixed side of the load frame in addition to a force-torque load cell in order to facilitate axial and torsion loading.
|The µTS offers sophisticated motion control and a high degree of precision. It is a versatile instrument, enabling a broad variety of experimental techniques. Designed for experimentalists, careful attention to details include:|
Dimensions in mm
The µTS incorporates a direct drive ball screw, rather than simple lead screws driven through a gearbox. The result is less friction, improved motion control and less maintenance. Moreover, lead screw actuators are typically limited to a narrow range of speeds.
Psylotest Control Software
The µTS control software is written in LabVIEW. It features test-segment specific digital filtering and integrated camera triggering, simplifying data and DIC image coordination. Advanced users have the option to modify the program to integrate external systems.
Alternative lead screw systems are typically limited to a narrow range of speeds. The direct drive ballscrew covers 9 orders of magnitude in speed. It can move as fast as a macro sized servohydraulic load frame or as slow as grass growing on a hot summer’s day. High speed enables versatility for more types of testing, including:
-Rate dependent studies
-Step load tests, such as creep or stress relaxation
-Effective load control
Large deformations can cause a specific area of interest to exit the microscope’s field of view during an experiment. Opposing left/right handed screws can mitigate this problem, but such a configuration exacerbates he centering problem for beam bending samples. Also, what happens when the area of interest is not in the center of the sample?
The µTS can be configured with a centering stage. The actuator of this secondary stage is slaved to the main system actuator such that any ratio of motion can be achieved. Relative cross-head motion is not tied to 50/50, and even beam bending samples can be maintained within the field of view.
In the µTS, the fixed cross-head, T-slot grip adapter, and load cell are integrated into a single part cut from a solid block of 17-4. This integration contributes to quality in situ image capture under high microscope magnification. Eliminating tolerance stack-up controls out-of-plane motion. The integration also greatly simplifies the system alignment procedure.
To further control out-of-plane motion, dual linear guides are symmetrically placed in the loading plane. Any moments from frictional effects are balanced and do not contribute to pitch or yaw. Previous designs placed linear guides below the loading plane, causing focus problems under high microscope magnification.
The µTS leverages proprietary Psylotech technology with 400 mV/V sensitivity compared to 2 mV/V from strain gauged alternatives typically found in universal load frames. The increased sensitivity means about 100x higher resolution, enabling multiple force scale experiments. For example, the stock 1.6 kN load cell can be used on tests where one would normally use a 16 N load cell. Advanced users could leverage this high sensitivity to enable new experiments, such as crack length from compliance or replacing acoustic sensors in composite tests.
The µTS monitors displacement on axis with the specimen. Alternative systems implement off-axis measurements, such that small pitch or yaw inevitable in real-world experiments show up as false displacement readings. In certain cases, rotary position and pitch are also used to infer displacement.
With the high-resolution on-axis displacement sensor, Psylotech has achieved better than 5 nm closed loop position control based on feedback from the cross-head displacement sensor. Such control is possible from a large stroke ball-screw actuator, because the feedback sensor measures displacement downstream of the screw in the load train.
精选已出版文章 Selected Publications
Runyu Zhang, Huiluo Chen, Sadeq Malakooti, Simon Oman, Bing Wang, Hongbing Lu, Huiyang Luo, Quasi-Static and Dynamic Confined Compressive Behavior of Glass Beads by In-Situ X-Ray Micro-Computed Tomography.
MehdiShishehbor, HyeyoungSon, MdNuruddin, Jeffrey P.Youngblood, ChelseaDavis, Pablo D.Zavattieri, Influence of alignment and microstructure features on the mechanical properties and failure mechanisms of cellulose nanocrystals (CNC) films.
University of Waterloo
Dibakar Mondal, Thomas L Willett, Extrusion Increases the Mechanical Properties of 3D-Printable Nanocomposite Biomaterials.
Shabanisamghabady, Mitra, Dislocation Slip and Deformation Twinning in Face Centered Cubic Low Stacking Fault Energy High Entropy Alloys (2020). All Dissertations. 2756.
Mitchell L. Rencheck, Andrew J. Weiss, Sami M. El Awad Azrak, Endrina S. Forti, Md. Nuruddin,
Jeffrey P. Youngblood, and Chelsea S. Davis*
ACS-Applied Polymer Materials (ACS Appl. Polym. Mater. 2020, 2, 578−584), Nanocellulose Film Modulus Determination via Buckling Mechanics Approaches
University of Utah, Dept. of Mechanical Engineering
Mirmohammad, H., Gunn, T. & Kingstedt, O.T.- Experimental Techniques, 2020. In-Situ Full-Field Strain Measurement at the Sub-grain Scale Using the Scanning Electron Microscope Grid Method.
The Graduate School Seoul National University, Department of Mechanical and Aerospace Engineering
Tomas Webbe Kerekes- Enhancement of Mechanoluminescence Sensitivity of SrAl2O4: Eu2+, Dy3+ Composite by Ultrasonic Curing Method.
University of Waterloo, Dept. of Systems Design Engineering
Dibakar Mondal & Thomas Willett, Mechanical properties of nanocomposite biomaterials improved by extrusion during direct ink writing.
University of Tennessee Knoxville, Department of Civil & Environmental Engineering
Mohmad Moshin Thakur & Dayakar Penumadu, Triaxial compression in sands using FDEM and micro-X-ray computed tomography.
Argonne National Laboratory
X Zhang, M Li, JS Park, P Kenesei, JD Almer, In-situ High-energy X-ray Study of Deformation Mechanisms in Additively Manufactured 316 Stainless Steel.
Argonne National Laboratory
M Li, X Zhang, JD Almer, JS Park, P Kenesei –2019, Final Report on Investigating Grain Dynamics in Irradiated Materials with High-Energy X-rays.
Lawrence Berkeley National Lab / University of California – Berkeley
Raja, S. N., Ye, X., Jones, M. R., Lin, L., Govindjee, S., & Ritchie, R. O. (2018). Microscopic mechanisms of deformation transfer in high dynamic range branched nanoparticle deformation sensors. Nature communications, 9(1), 1155.
Adams, D., & Turner, C. J. (2018). An implicit slicing method for additive manufacturing processes. Virtual and Physical Prototyping, 13(1), 2-7.
U.S. Army Research Lab
Cline, J., Wu, V., & Moy, P. (2018). Assessment of the Tensile Properties for Single Fibers (No. ARL-TR-8299). US Army Research Laboratory Aberdeen Proving Ground United States.
University of California – Berkeley
Gu, X. W., Ye, X., Koshy, D. M., Vachhani, S., Hosemann, P., & Alivisatos, A. P. (2017). Tolerance to structural disorder and tunable mechanical behavior in self-assembled superlattices of polymer-grafted nanocrystals. Proceedings of the National Academy of Sciences, 201618508.
Sane, H. (2017). A Holistic Investigation and Implementation of Fluidic Origami Cellular Solid for Morphing and Actuation.
Baikerikar, P. J., & Turner, C. J. (2017, August). Comparison of as-built FEA simulations and experimental results for additively manufactured dogbone geometries. In ASME 2017 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers.
U.S. Army Research Lab
Roenbeck, M. R., Sandoz-Rosado, E. J., Cline, J., Wu, V., Moy, P., Afshari, M., Reichert, D., Lustig, S.R., & Strawhecker, K. E. (2017). Probing the internal structures of Kevlar® fibers and their impacts on mechanical performance. Polymer, 128, 200-210.
Cole, D. P., Henry, T. C., Gardea, F., & Haynes, R. A. (2017). Interphase mechanical behavior of carbon fiber reinforced polymer exposed to cyclic loading. Composites Science and Technology, 151, 202-210.
Iowa State University, Ames Laboratory
Tian, L., Russell, A., Riedemann, T., Mueller, S., & Anderson, I. (2017). A deformation-processed Al-matrix/Ca-nanofilamentary composite with low density, high strength, and high conductivity. Materials Science and Engineering: A, 690, 348-354.
Czahor, C. F., Anderson, I. E., Riedemann, T. M., & Russell, A. M. (2017, July). Deformation processed Al/Ca nano-filamentary composite conductors for HVDC applications. In IOP Conference Series: Materials Science and Engineering(Vol. 219, No. 1, p. 012014). IOP Publishing.
University of New Hampshire
Knysh, P., & Korkolis, Y. P. (2017). Identification of the post-necking hardening response of rate-and temperature-dependent metals. International Journal of Solids and Structures, 115, 149-160.
University of New Hampshire
Zhai, J., Luo, T., Gao, X., Graham, S. M., Baral, M., Korkolis, Y. P., & Knudsen, E. (2016). Modeling the ductile damage process in commercially pure titanium. International Journal of Solids and Structures, 91, 26-45.
Ripley, P. W., & Korkolis, Y. P. (2016). Multiaxial deformation apparatus for testing of microtubes under combined axial-force and internal-pressure. Experimental Mechanics, 56(2), 273-286.
点击上图进入配置说明 For typical configurations, Please click image above.
The core motion control technologies for the µTS were developed in an Army Research Lab WMRD SBIR. Collaboration with Prof. Ioannis Chasiotis at the University of Illinois Urbana-Champaign was critical to that effort. The goal was to apply lessons learned by the Chasiotis group, making them commercially accessible and more user-friendly. In the process, Psylotech added its high resolution sensor technologies and developed a near-nano scale positioning ball screw actuator to create the µTS.
In the rush to understanding the nano scale, six orders of magnitude in length scale were glossed over. The µTS takes advantage of digital image correlation for local strain measurement on these “meso” length scales between 10 mm and 5 nm.