We are pleased to inform you that Ebatco’s Nano Analysis and Testing Laboratory (NAT Lab) now is open to serve your nanoscale mechanical and tribological testing and analysis needs. The NAT Lab’s staff scientists have more than 10 years of nanomechanical and nanotribological testing, applications R&D and instrument development experience. The lab is equipped with state-of-the-art nanoindenters with nm-resolution in-situ SPM imaging capability and full lines of advanced options such as nanoDMA, modulus mapping, feedback control, heating/cooling stage, vacuum chuck, and environmental control and isolation chamber.

Abstract:

As the thickness of coating thin
film is reduced it becomes increasingly difficult to measure their adhesion,
hardness, toughness by conventional methods. Indentation test methods are well
established for the determination of elastic modulus and hardness, but methods
for assessment of fracture properties are much less developed. In this term
paper, existing metrology of using indention to study fracture toughness will
be summarized and mechanics of fracture under indentation will be studied.
Experimental plans of investigation fracture toughness of OSG low-K film will
also be evaluated in the end.

Can we map the eastic modulus of a and c domians? Can we mechanically switch the domains and let them function as nanoactuators and sensors?

B. Li, M. K. Kang, K. Lu, R. Huang, P. S. Ho, R. A. Allen, and M. W. Cresswell, Nano Letters 8, 92 -98 (2008). (Web Release Date: 07-Dec-2007; DOI: 10.1021/nl072144i)

The review paper, "Viscoelastic effects in small-scale indentation of biological materials" has been published in International Journal of Surface Science and Engineering 2007 - Vol. 1, No.2/3 pp. 180 - 197 .  This work presents both a review of analytical (linear) viscoelasticity in the context of contact-probe mechanical characterization and summarizes the available literature on application of these techniques to measurements of biological material creep and relaxation responses.  

Nanoindentation testing of time-dependent materials is becoming increasingly relevant with advances in areas such as polymer science and the study of materials in biological systems. However, mechanical characterization at micrometer or nanometer length scales is not trivial in such materials that may be highly compliant, heterogeneous, or possess unique morphological characteristics. Although many researchers have made progress in overcoming key challenges that are involved in testing non-traditional materials, significant advancements must still be made to optimize testing methodologies and analytical techniques.

How can we see load dipslacement cyrve of residual stressed material. I mean I m interested in extracting indentation properties from ABAQUS for material which has got some pre stress in terms of residual stress. What is procedure of assigning residual stress to some material in ABAQUS?

This model has a simple closed-form analytical expression, matching with finite element results nearly perfectly.

Ref: G. Feng, S. Qu, Y. Huang and W.D. Nix, An analytical expression for the stress field around an elastoplastic indentation/contact, Acta Materialia, V.55, 2007, P2929-2938. http://dx.doi.org/10.1016/j.actamat.2006.12.030

(cross-post to Biomch-L )

Two symposia solicit papers on biomechanics topics for the upcoming Materials Research Society meeting, November 26-30, 2007, Boston,  MA.  Short-form abstracts are due 20 June, 2007.

Symposium AA, Fundamentals of Nanoindentation and Nanotribology IV, solicits papers on the subject of nanomechanical characterization of  biological materials including biomolecules, cells and tissues.   Further details can be found here .

First announcement and call for papers.

The symposium "Fundamentals of Nanoindentation and Nanotribology" will run for the fourth time at the Fall, 2007, Materials Research Society Meeting, Boston, MA, USA.   

Attached is the first announcement and call for papers for "nanomech 8", the 8th European Symposium on Nanomechanical Testing to be held in Huckelhoven, Germany, 3rd-5th September, 2007. Full details are also available at the conference website. The special focus for this year's meeting is "Across the scales: Size effects and scaling phenomena in micro- and nano-mechanics". Abstracts are due 5th May, 2007.

A viscous-elastic-plastic indentation model was used to assess the local variability of properties in healing porcine bone. Constant loading- and unloading-rate depth-sensing indentation tests were performed and properties were computed from nonlinear curve-fits of the unloading displacement-time data. Three properties were obtained from the fit: modulus (the coefficient of an elastic reversible process), hardness (the coefficient of a nonreversible, time-independent process) and viscosity (the coefficient of a nonreversible, time-dependent process). The region adjacent to the dental implant interface demonstrated a slightly depressed elastic modulus along with an increase in local time-dependence (lower viscosity); there was no clear trend in bone hardness with respect to the implant interface.

Experiments with a multidimensional nano-contact system (Lucas, Hay, and Oliver, J. Mater. Res. 2004) have shown that, prior to kinetic frictional sliding, there is a significant reduction of the tangential contact stiffness relative to the elastic prediction. The reduction occurs at contact sizes below about 50~200nm for aluminum single crystals and several other materials. Using a cohesive interface model, we find that this reduction corresponds to a transition from a small-scale-slip to large-scale-slip condition of the interface.