Deformity of the forearm due to growth disturbance of the ulna occurs in a number of conditions such as ulnar deficiency, multiple exostoses, and neurofibromatosis. We report a previously unrecognised form, caused by focal cortical indentation. We have treated five children with this condition, three girls and two boys; the mean age at presentation was 5 years (2 to 8). The deformity was first ...

A new physical model based on mesoscale self-assembly is developed to simulate indentation fracture in crystalline materials. Millimeter-scale hexagonal objects exhibiting atom-like potential functions were designed and allowed to self-assemble into two-dimensional (2D) aggregates at the interface between water and perfluorodecalin. Indentation experiments were performed on these aggregates, an...

This paper provides an overview of recent efforts at the National Institute of Standards and Technology (NIST) to develop metrology and standards to support general users of instrumented indentation and scan-probe devices. Research directed towards a primary realization of force in the regime below 10 μN, development and characterization of novel compact microforce sensors, scan-probe force cal...

57 A methodology for interpreting instrumented sharp indentation with dual sharp indenters with different tip apex 58 angles is presented by recourse to computational modeling within the context of finite element analysis. The forward 59 problem predicts an indentation response from a given set of elasto-plastic properties, whereas the reverse analysis 60 seeks to extract elasto-plastic propert...

In this work, the deformation behavior of as-prepared (AP) and structurally relaxed (SR) Cu–Zr–based nanoglasses (NGs) are investigated using nano- micro-indentation. The NGs subjected to structural relaxation by annealing them close glass transition temperature without altering their amorphous nature. indentation load, p , vs. displacement, h curves SR samples characterized discrete displaceme...

The study of indentation responses of rate-dependent (viscoplastic or creeping) solids has generally focused on the relationship between indentation hardness and an effective strain rate, which can be defined from a similarity transformation of the governing equations. The strain rate sensitivity exponent can be determined from the slope of a log-log plot of the hardness versus effective strain...

INTRODUCTION: The topographic analysis of cartilage mechanical properties has been of particular interest since it is known that physiological loading patterns differ with location in a synovial joint. Site-specific in vivo material characterization of articular cartilage has previously been performed using both ultrasound and indentation techniques [1-3]. Ultrasound biomicroscopy (UBM) uses hi...

An approach for combined imaging of elastic and electromechanical properties of materials, referred to as piezoacoustic scanning probe microscopy PA-SPM , is presented. Applicability of this technique for elastic and electromechanical imaging with nanoscale resolution in such dissimilar materials as ferroelectrics and biological tissues is demonstrated. The PA-SPM signal formation is analyzed b...

The possibility of a third phase, often referred to as the interphase, in polymer composites is well known, and there have been many attempts to characterise the mechanical properties of this region at the nanoscale. Despite the increasing resolution of nano-indentation and atomic force microscopy techniques, it is not always possible to identify thin interphases when the dimensions are similar...

A systematic study of depth-sensing indentation was performed on nanocrystalline (nc) Ni–W alloys specially synthesized with controlled unidirectional gradients in plastic properties. A yield strength gradient and a roughly constant Young’s modulus were achieved in the nc alloys, using electrodeposition techniques. The force vs. displacement response from instrumented indentation experiments ma...