Dear Editor-in-Chief, I am writing as an engineer and orthopaedic surgeon to express a few concerns about methodology for mechanical testing appearing in your journal over the years. The latest example is that by Hutcheson, et al., “Comparison of double locking plate constructs with single non-locking plate constructs in single cycle to failure in bending and torsion”, that appeared in VCOT iss...

One edge of an elastic rod is inserted into a friction-less and fitting socket head, whereas the other edge is subjected to a torque, generating a uniform twisting moment. It is theoretically shown and experimentally proved that, although perfectly smooth, the constraint realizes an expulsive axial force on the elastic rod, which amount is independent of the shape of the socket head. The axial ...

worldwide networks of seismic recording instruments mostly record only translational ground motion in two or three orthogonal directions. rotational component of earthquake is not commonly recorded. several theories are available to estimate a torsional component from recorded translational components of ground motion. in this paper detailed investigations are made to study the relative perform...

INTRODUCTION The purpose of this study was to evaluate the effect of various degrees of cyclic fatigue on torsional failure and torsional preloading on the cyclic fatigue life of heat-treated K3XF nickel-titanium (NiTi) instruments (SybronEndo, Orange, CA). METHODS The mean number of cycles until failure (Nf) of K3XF and K3 NiTi instruments was examined in a 3-point bending apparatus with a 7...

We report the fabrication and characterization of paddle oscillators featuring nanometer-scale supporting rods. The devices show two resonances in the 1–10 MHz range, which we attribute to the translational and torsional modes of motion. While the frequency response of the translational motion shows evidence of nonlinear behavior, the torsional response remains symmetric throughout the range of...

Eye torsion was examined in 13 astronaut subjects, tested during repeated episodes of 0 G and 1.8 G in parabolic flight aboard NASA's KC-135. Four findings are included. 1) A strong relationship between previous history of SMS and ocular torsional disconjugacy in novel gravitational states. 2) Responses were unchanged in 4 subjects retested a year later. 3) Ocular torsional disconjugacy scores ...

Studies of torsional properties of natural silk fibers seem to open a new window in understanding the correlation between their extraordinary mechanical properties and their microscopic structure. In this paper, the torsional relaxation profiles of single-stranded Bombyx mori silk was obtained from our experiment, and a prominent under-damping mode was identified. It was concluded that the sing...

DNA supercoiling plays an important role in a variety of cellular processes. The torsional stress related to supercoiling may also be involved in gene regulation through the local structure and dynamics of the double helix. To check this possibility, steady torsional stress was applied in the course of all-atom molecular dynamics simulations of two DNA fragments with different base pair sequenc...

Manufacturing and Testing techniques were investigated for the development of efficient joining of composite tubes. The stepped lap joining arrangements were studied. Finite element models were developed using ANSYS finite element code for predicting the stress distribution of the joint under the applied loads. Tubes made of graphite/epoxy were considered. The tubes were tested under both tensi...