PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 7263032

The comparative stiffness of external fixation frames.

G E Kempson·D Campbell
View original source ↗Export metadata ↓

Abstract

The stiffness of 6 external fixation frames was compared by measuring the deflection which occurred at an unstable fracture, created in a tibia in vitro. All tests were repeated with the frames applied to pins brazed into a steel tube, in order to eliminate any errors caused by variation in the quality of the bone under test. The results of these tests are presented and observations are made on some design features of the frames. It was found that the 2 most critical factors which determined the stiffness of a frame were the diameter and the number of pins used to transfix the bone. Other factors, such as the stiffness of the connecting bar, were of secondary importance.

Explore related subjects

Biomedical EngineeringBone NailsEvaluation Studies as TopicFracture FixationHumansTibial FracturesComparative StudyJournal Article

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

G E Kempson, D Campbell. 1981. The comparative stiffness of external fixation frames.. https://doi.org/10.1016/0020-1383(81)90205-9

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2007

Optimal design of non-Newtonian, micro-scale viscous pumps for biomedical devices.

The present paper addresses the numerical optimization of geometrical parameters of non-Newtonian micro-scale viscous pumps for biomedical devices. The objective is to maximize the mass flow rate per unit of shaft power consumed by the rotor when an external pressure load is applied along the channel that houses the rotor. Two geometric parameters are considered in the optimization process: (i) the height of the channel that houses the rotor (H) and (ii), the eccentricity (epsilon) of the rotor. Three different micro-scale viscous pump configurations were tested: a straight-housed pump (I-shaped housing) and two curved housed pumps (L- and U-shaped housings). The stress-strain constitutive law is modeled by a power-law relation. The results show that the geometric optimization of micro-scale viscous pumps is critical since the mass flow rate propelled by the rotor is highly dependent on epsilon and H. Numerical simulations indicate that mass flow rate is maximized when epsilon approximately 0, namely when the rotor is placed at a distance of 0.05 radii from the lower wall. The results also show that micro-scale viscous pumps with curved housing provide higher mass flow rate per unit of shaft power consumed when compared with straight-housed pumps. The results are presented in terms optimized dimensions of all three configurations (i.e., H(opt) and epsilon(opt)) and for values of the power-law index varying between 0.5 (shear thinning fluids) and 1.5 (shear-thickening fluids).

Biomedical Engineering↗