Ortho Development Corporation

Draper, UT, United States

Ortho Development Corporation

Draper, UT, United States
SEARCH FILTERS
Time filter
Source Type

Sanders A.P.,University of Utah | Sanders A.P.,Ortho Development Corporation | Brannon R.M.,University of Utah
Journal of Biomechanics | Year: 2011

The components of prosthetic hip bearings may experience in-vivo subluxation and edge loading on the acetabular socket as a result of joint laxity, causing abnormally high, damaging contact stresses. In this research, edge-loaded contact of prosthetic hips is examined analytically and experimentally in the most commonly used categories of material pairs. In edge-loaded ceramic-on-ceramic hips, the Hertzian contact theory yields accurate (conservatively, <10% error) predictions of the contact dimensions. Moreover, the Hertzian theory successfully captures slope and curvature trends in the dependence of contact patch geometry on the applied load. In an edge-loaded ceramic-on-metal pair, a similar degree of accuracy is observed in the contact patch length; however, the contact width is less accurately predicted due to the onset of subsurface plasticity, which is predicted for loads >400. N. The Hertzian contact theory is shown to be ill-suited to edge-loaded ceramic-on-polyethylene pairs due to polyethylene's nonlinear material behavior. This work elucidates the methods and the accuracy of applying classical contact theory to edge-loaded hip bearings. The results help to define the applicability of the Hertzian theory to the design of new components and materials to better resist severe edge loading contact stresses. © 2011 Elsevier Ltd.


Sanders A.P.,Ortho Development Corporation | Brannon R.M.,University of Utah
Journal of Tribology | Year: 2011

Laboratory testing of contact phenomena can be prohibitively expensive if the interacting bodies are geometrically complicated. This work demonstrates means to mitigate such problems by exploiting the established observation that two geometrically dissimilar contact pairs may exhibit the same contact mechanics. Specific formulas are derived that allow a complicated Hertzian contact pair to be replaced with an inexpensively manufactured and more easily fixtured surrogate pair, consisting of a plane and a spheroid, which has the same (to second-order accuracy) contact area and pressure distribution as the original complicated geometry. This observation is elucidated by using direct tensor notation to review a key assertion in Hertzian theory; namely, geometrically complicated contacting surfaces can be described to second-order accuracy as contacting ellipsoids. The surrogate spheroid geometry is found via spectral decomposition of the original pair's combined Hessian tensor. Some numerical examples using free-form surfaces illustrate the theory, and a laboratory test validates the theory under a common scenario of normally compressed convex surfaces. This theory for a Hertzian contact substitution may be useful in simplifying the contact, wear, or impact testing of complicated components or of their constituent materials. © 2011 American Society of Mechanical Engineers.


Trademark
Ortho Development Corporation | Date: 2014-08-07

Orthopedic implants, prosthesis and instrumentation, namely, artificial orthopedic joint implants, joint prostheses and surgical instruments all for total joint replacement.


Trademark
Ortho Development Corporation | Date: 2013-08-06

Orthopedic prostheses and implants consisting of artificial materials, namely, femoral hip stem for total and hemi hip arthroplasty.


Trademark
Ortho Development Corporation | Date: 2014-07-28

Spinal fixation implants and instruments, namely pedicle screw system consisting of rods, polyaxial screws, extended tab screws, monoaxial screws, and set screws which can be variously assembled to provide immobilization of the thoracolumbar and lumbosacral spine.


Trademark
Ortho Development Corporation | Date: 2014-11-18

Orthopedic tibial prostheses and implants of artificial materials for total knee arthroplasty.


Trademark
Ortho Development Corporation | Date: 2016-09-02

Orthopedic implants, namely, titanium cones and sleeves for use in revision knee arthroplasty.


Trademark
Ortho Development Corporation | Date: 2014-06-10

Orthopedic implants and prosthesis, namely knee prosthesis.


Trademark
Ortho Development Corporation | Date: 2013-08-06

Orthopedic prostheses and implants consisting of artificial materials, namely, femoral hip stem for total and hemi hip arthroplasty.


Trademark
Ortho Development Corporation | Date: 2014-08-21

Knee system for total knee arthroplasty; and orthopedic implants and prosthesis, namely, knee prosthesis.

Loading Ortho Development Corporation collaborators
Loading Ortho Development Corporation collaborators