Linked Life Data

11996031

Source:http://linkedlifedata.com/resource/pubmed/id/11996031

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
2002-5-8
pubmed:abstractText
Despite the critical role that shear is hypothesized to play in the damage modes that limit the performance of total hip and knee replacements, the shear behavior of ultra-high molecular weight polyethylene (UHMWPE) remains poorly understood, especially after oxidative degradation or radiation crosslinking. In the present study, we developed the miniature specimen (0.5 mm thickness x 6.4mm diameter) shear punch test to evaluate the shear behavior of UHMWPE used in total joint replacement components. We investigated the shear punch behavior of virgin and crosslinked stock materials, as well as of UHMWPE from tibial implants that were gamma-irradiated in air and shelf aged for up to 8.5 years. Finite element analysis, scanning electron microscopy, and interrupted testing were conducted to aid in the interpretation of the shear punch load-displacement curves. The shear punch load-displacement curves exhibited similar distinctive features. Following toe-in, the load-displacement curves were typically bilinear, and characterized by an initial stiffness, a transition load, a hardening stiffness, and a peak load. The finite element analysis established that the initial stiffness was proportional to the elastic modulus of the UHMWPE, and the transition load of the bilinear curve reflected the development of a plastically deforming zone traversing through the thickness of the sample. Based on our observations, we propose two interpretations of the peak load during the shear punch test: one theory is based on the initiation of crystalline plasticity, the other based on the transition from shear to tension during the tests. Due to the miniature specimen size, the shear punch test offers several potential advantages over bulk test methods, including the capability to directly measure shear behavior, and quite possibly infer ultimate uniaxial behavior as well, from shelf aged and retrieved UHMWPE components. Thus, the shear punch test represents an effective and complementary new tool in the armamentarium of miniature specimen mechanical testing methods for UHMWPE used in total joint replacement components.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0142-9612
pubmed:author
pubmed:issnType
Print
pubmed:volume
23
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1907-19
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Miniature specimen shear punch test for UHMWPE used in total joint replacements.
pubmed:affiliation
Exponent, Inc., Philadelphia, PA 19103, USA. skurtz@exponent.com
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't