Journal: Experimental Mechanics

Abbreviation

Exp. mech.

Publisher

Springer

Journal Volumes

ISSN

0014-4851
1741-2765

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Publications 1 - 10 of 15
  • Thin and Thermally Stable Periodic Metastructures
    Item type: Journal Article
    Gdoutos, E.; Shapiro, A.A.; Daraio, C. (2013)
    Experimental Mechanics
  • Multiaxial Mechanical Characterization of Interpenetrating Polymer Network Reinforced Acrylic Elastomer
    Item type: Journal Article
    Schmidt, A.; Bergamini, A.; Kovacs, G.; et al. (2011)
    Experimental Mechanics
  • Novel Method for Analyzing Crack Growth in Polymeric Microtensile Specimens by In Situ Atomic Force Microscopy
    Item type: Journal Article
    Lang, U.; Suess, T.; Wojtas, N.; et al. (2010)
    Experimental Mechanics
  • Adaptive Neutron Radiography Correlation for Simultaneous Imaging of Moisture Transport and Deformation in Hygroscopic Materials
    Item type: Journal Article
    Sanabria, Sergio J.; Lanvermann, Christian; Michel, F.; et al. (2014)
    Experimental Mechanics
  • Dynamic characterization of vertically aligned carbon nanotube foams
    Item type: Other Conference Item
    Thevamaran, Ramathasan; Daraio, Chiara (2013)
    Experimental Mechanics
  • Micro-Scale Restraint Methodology for Humidity Induced Swelling Investigated by Phase Contrast X-Ray Tomography
    Item type: Journal Article
    Patera, Alessandra; Jefimovs, Konstantins; Rafsanjani, Ahmad; et al. (2014)
    Experimental Mechanics
    A new methodology for restraining the swelling of spruce wood samples in the micrometre range is developed and presented. We show that the restraining device successfully prevents the free swelling of wood during moisture adsorption, thus modifying significantly the anisotropy of swelling and provoking the intended collapse and large deformations of the wood cells at the edges of the sample in contact with the restraining device. The device consists in a slotted cube designed to restrain swelling and is made of PMMA manufactured by laser ablation. The sample undergoing the restraining experiment is imaged with high-resolution synchrotron radiation phase contrast X-Ray Tomographic Microscopy. The deformation of the restraining device itself is only approximately 2 μm with respect to a 500 μm width in cubes containing latewood samples and half of that in the case of cubes containing earlywood.
  • A new experimental technique for the multi-axial testing of advanced high strength steel sheets
    Item type: Journal Article
    Mohr, D.; Oswald, Mariella (2008)
    Experimental Mechanics
  • An Experimental Technique for the Dynamic Characterization of Soft Complex Materials
    Item type: Journal Article
    Thevamaran, Ramathasan; Daraio, C. (2014)
    Experimental Mechanics
    We describe an experimental technique to study the dynamic behavior of complex soft materials, based on high-speed microscopic imaging and direct measurements of dynamic forces and deformations. The setup includes high sensitivity dynamic displacement measurements based on geometric moiré interferometry and high-speed imaging for in-situ, full-field visualization of the complex micro-scale dynamic deformations. The method allows extracting dynamic stress-strain profiles both from the moiré interferometry and from the high-speed microscopic imaging. We discuss the advantages of using these two complementing components concurrently. We use this technique to study the dynamic response of vertically aligned carbon nanotube foams subjected to impact loadings at variable deformation rates. The same technique can be used to study other micro-structured materials and complex hierarchical structures.
  • Reaching Large Strains During Simple Shear Experiments Thanks to Sequential Re-Machining of the Free Edges
    Item type: Journal Article
    Colon, Xavier; Galpin, Bertrand; Mahéo, Laurent; et al. (2024)
    Experimental Mechanics
    Background The simple shear experiment is widely used for the calibration of plasticity models due to straightforward post processing. The specimen can be as simple as a rectangular strip of sheet metal, but the maximum strain is limited by early initiation of fractures from the free edges. Avoiding this drawback has been a major motivation for the development of new specimens with optimized edge geometries or the in-plane torsion test, but at the cost of a more complex analysis of the test and often a reduction of the gauge section. Objective The objective of the present work is to overcome the initiation of fracture from the free edges during simple shear experiments. Our goal is to double the achievable maximum strain, while keeping the size of the specimen and the post processing simplicity of a standard simple shear test. Methods A sequential single shear test is proposed, consisting of several two steps sequences on a notched geometry. First, an interrupted shear test is performed up to a specified displacement value. Then, the damaged free edges of the specimen are removed through milling. The specimen is then ready for the following sequence of shear and re-machining. Results Experiments are performed on three engineering materials, with up to five loading-machining sequences. The maximum attained effective strain is up to two times the one reached during a monotonic experiment. Numerical simulations are used to validate the shear stress and strain calculations from experimental measurements. Practical recommendations are derived for the choice of the displacement step size and Digital Image Correlation analysis. Conclusion It is found that the maximum strain attained before the undesired failure of the specimen during simple shear test can be substantially extended through repeated re-machining of the specimen boundaries, enabling behavior identification at larger strains.
  • Silicon-Based Microscale Multistable Metamaterials: Microfabrication and Characterization
    Item type: Journal Article
    Bronstein, Emil; Ilssar, Dotan; Kannan, Vignesh; et al. (2025)
    Experimental Mechanics
    Background The design space of multistable reconfigurable metamaterials, typically constructed of bistable unit cells, is virtually limitless; yet, many existing fabrication methods suffer from low spatial resolution or limited build volumes. This limits scalability and the construction of complex architectures composed of numerous building blocks. Microfabrication on silicon wafers overcomes these limitations, offering a scalable manufacturing route for architectures with large numbers of unit cells on a single wafer. Actuating and measuring the unstable response of microscale bistable structures is not trivial, calling for the development of specialized experimental tools. Objective (i) A scalable microfabrication protocol for creating multistable metamaterials composed of unprecedented numbers of bistable unit cells. (ii) An experimental method for actuating microscale bistable structures and characterizing their mechanical response to quasistatic loading in situ. Methods We employ microfabrication to realize free-standing, silicon-based, wafer-scale multistable metamaterials using photolithography, deep reactive ion etching, and vapor hydrogen fluoride etching, along with an experimental setup leveraging a micro-needle, a position-sensing detector, and in-situ full-field imaging for actuation and characterization. Results Bistable structures with a range of design parameters, along with various multistable chains comprising 5, 10, and 100 unit cells, have been successfully microfabricated on a single wafer. The non-monotonic force-displacement relations, characteristic of bistable structures, have been measured, linking structural design to mechanical behavior through experiments. Conclusions The established framework enables the creation and characterization of unit cells with tunable multistability, admitting closed-loop feedback between structural design, microfabrication, and characterization. This lays the foundation for metamaterial architectures with diverse functionality.
Publications 1 - 10 of 15