Evaluation of Global Load Sharing and Shear-lag Models to Describe Mechanical Behavior in Partially Lacerated Tendons

1 Evaluation of Global Load Sharing and Shear-lag Models to Describe Mechanical Behavior in Partially Lacerated Tendons Marco Pensalfini, 1,2 Sarah Duenwald-Kuehl, 2,3 Jaclyn Kondratko-Mittnacht, 2,3 Roderic Lakes, 4, 5 and Ray Vanderby, Jr. 2, 3, 5* 1 Department of Industrial Engineering, University of Bologna, Bologna, Italy 2 Department of Biomedical Engineering, 3 Department of Orthopedic and Rehabilitation, 4 Department of Engineering Physics, and 5 Department of Materials Science, University of Wisconsin-Madison, Madison, Wisconsin * Address correspondence to Ray Vanderby, Jr. E-mail: [email protected]; Mailing address 5059 Wi Institute Medical Research 1111 Highland Ave Madison, WI 53705 ABSTRACT The mechanical effect of a partial thickness tear or laceration of a tendon is analytically modeled under various assumptions and results are compared with previous experimental data. Among several fibril-level models considered, a shear-lag model that incorporates fibril-matrix interaction and a fibril-fibril interaction defined by the contact area of the interposed matrix best matched published data for tendons with shallow cuts (less than 50% of the cross-sectional area). Application of this model to the case of many disrupted fibrils is based on linear superposition and is most successful when more fibrils are incorporated into the model. An equally distributed load sharing model for the fraction of remaining intact fibrils was inadequate in that it overestimates the strength for a cut less than half of the tendon’s cross-sectional area. In a broader sense, results imply that shear lag contributes significantly to the general mechanical behavior of tendons when axial loads are non-uniformly distributed over a cross-section, although the predominant hierarchical level and microstructural mediators for this behavior require further inquiry. Key words: global load sharing, shear lag, tendon, laceration

Evaluation of Global Load Sharing and Shear-lag Models to Describe Mechanical Behavior in Partially Lacerated Tendons

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