Simple shear testing of parallel-fibered planar soft tissues

Area of Science:

• Biomechanics
• Soft Tissue Mechanics
• Materials Science

Background:

• Simple shear tests offer unique insights into parallel-fibered soft tissues by isolating fiber response.
• Strain field inhomogeneities from clamping and edge effects require documentation.

Purpose of the Study:

• To investigate finite simple shear of simulated ligament material parallel to fiber direction.
• To assess the impact of aspect ratio, clamping prestrain, and bulk modulus on strain homogeneity.

Main Methods:

• Utilized the finite element method (FEM) for simulating simple shear.
• Employed a transversely isotropic, hyperelastic material model.
• Varied aspect ratios, clamping prestrain, and bulk moduli.

Main Results:

• Identified a central region of uniform strain for specific geometries.
• An aspect ratio of 1:2 (fiber to cross-fiber) maximized the uniform strain area.
• Deformation remained nearly isochoric across tested bulk moduli, suggesting suitability for isolating viscoelasticity.

Conclusions:

• The simple shear test can characterize matrix properties in parallel-fibered soft tissues.
• Planar measurements are sufficient for strain characterization.
• This test configuration is adaptable for studying matrix, fiber-matrix, and fiber-fiber interactions.