How does FTOLN affect convergence & Accuracy of results?
After FKN, FTOLN is the next parameter that affects both convergence & accuracy. Its usually known as Penetration Tolerance(TOLN) This is a factor of the depth of the underlying element. If the underlying elements depth was [h], and if FTOLN is specified as 0.1 (default value), a penetration of (0.1*h) is allowed. If this value was exceeded during the solution, then solution does not converge. Its aborted. In effect, this value can be treated as the Maximum allowable penetration. Setting too small a value can also affect in the form of excessive iterations or non-convergence. Return to Top 48. How and where is contact detected? For STS elements, only the Target elements can penetrate into the Contact Elements and NOT vice-versa. Gauss-Integration points on the Contact Surface act as the Contact detection points. This is the default setting and is recommended for most cases. The Newton-Cotes/Lobatto nodal integration scheme, uses the Nodes of the Contact elements as Contact Detection po
