In comparison, we have reported that the effective tissue stiffness of AV leaflet belly region was 150 200 kPa [Merryman, W.D., Huang, H.Y.S., Schoen, F.J., Sacks, M.S. (2006). The effects of cellular contraction on AV leaflet flexural stiffness. Journal of Biomechanics 39 (1), 88 96], which was also independent of direction and amount of flexure.
This effect is conventionally ignored but more evidence has shown that calculation and analyses ignoring this effect could significantly overestimate flexure strength and stiffness.
The metrology platform consists of a 1 DoF Lorentz actuator with gravity compensator, a low stiffness flexure-based guiding mechanism and a moving mass of 4 kg with high structural resonance frequencies.
A study of a more complex flexure showed that simple stiffness models were inaccurate because of end effects in the supporting structure.
The structural performance under service load (i.e.: stiffness in flexure) is mostly affected by the corrosion of the tension reinforcement (steel cross-section and the steel concrete bond reduction).
It was implemented in a study to compare the effect of uni-directional cyclic flexure on the effective stiffness of two candidate TEHV scaffolds: a non-woven mesh of polyglycolic acid (PGA) fibers, and a non-woven mesh of PGA and poly l-lactic acid (PLLA) fibers, both coated with poly 4-hydroxybutyrate (P4HB).
It is shown that some lattice flexures exhibit a torsional/bending stiffness ratio as much as 1.7 times higher than an equal aspect-ratio blade flexure, and a transverse bending/motion-direction bending stiffness ratio up to 6.5 times higher than an equal aspect-ratio blade flexure.
The resulting solution was found to correlate with the effective lateral-flexure, torsional and coupling stiffness coefficients to yield a general semi-analytical solution.
The proposed novel module can be used as the building block of more complex flexures to improve their stiffness characteristics, diminish their error motions and widen their stability region.
