An alternative finite element model for simulation of frictional gap

Abstract

This study is an attempt to modeling a frictional gap in a crack closure process under compressive loading conditions in which the crack surfaces are in touch and the effects of friction between them are significant. An iterative finite element (FE) solution is developed to model a finite crack in an interfacial layer with varying material properties. A mere application of a Lagrange multiplier formulation (node-to-node, NTN, or node-to-segment, NTS) in a developed FE framework to fulfill the contact constraints between contacting surfaces is discussed which improves the penalty formulation used in ANSYS. We then argue that the penalty formulation allows for a certain amount of crack surface interpenetration whereas the Lagrange multiplier formulation fulfils the contact constraints more accurately. This technique is easy to implement and offers higher accuracy than the equivalent FE solution, available in commercial FE software such as ANSYS 9.0, to the same system.

Improving finite element results in modeling heart valve mechanics

“…The closed form of the equilibrium equation and the equation of compatibility disregarding body force is written as such 12,13 Here, s xx , s yy , and t xy are the stress values obtained from the coarse mesh FE models applied to an arbitrary body shape. Let's define the elevated valves as ŝ xx , ŝ yy , and t xy which are comparable with results obtained from fine mesh FE models.…”

“…The closed form of the equilibrium equation and the equation of compatibility disregarding body force is written as such 12,13…”

Prosthetic Aortic Heart Valves

“…The ventricularis covers all but the coaptation region where two adjacent leaflets contact and consists of almost 50% collagen (90% Type I collagen), 20% elastin. The fibrosa's structure is oriented in the circumferential direction shown in Figure 7 [54].…”