Stress-Strain Index

Stress-Strain Index

Der Stress-Strain-Index (SSI) (zu Deutsch: Verformungs-Spannungs-Index), eines Knochens ist ein Surrogat für seine Festigkeit bzw. Biegefestigkeit[1]. Der SSI dient primär zum Vergleich der Analyse von Querschnitt-Scans mittels QCT/pQCT-Systemen und den Ergebnissen von Drei-Punkt-Biegestests (Festigkeit).

Definition

Der SSI wird wie folgt berechnet:[2]

SSI = \sum_{i=0}^n {{r_i^2 a ({{CD} \over {ND}})} \over {r_{max}}}

Wobei:

Anwendung

Der SSI wurde entwickelt, um ein besseres Maß der Festigkeit eines Knochens [2] zu erhalten, als es die reine Berechnung des Flächenträgheitsmoments ermöglicht. Daher ermöglicht er den einfachen Vergleich von In-vivo-Messergebnissen zu Ergebnissen typischer Materialprüfungstests wie z.B: dem 3-Punkt-Biegestest.

Einzelnachweise

  1. ↑ Ward K, Roberts S, Adams J, Mughal M: Bone geometry and density in the skeleton of pre-pubertal gymnasts and school children.. In: Bone. 36, Nr. 6, 2005, S. 1012-8. PMID 15876561
  2. ↑ a b Hasegawa Y, Schneider P, Reiners C: Age, sex, and grip strength determine architectural bone parameters assessed by peripheral quantitative computed tomography (pQCT) at the human radius.. In: J Biomech. 34, Nr. 4, 2001, S. 497-503. PMID 11266673

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