A fully general and adaptive inverse analysis method for cementitious materials

A new inverse analysis approach for predicting the fracture mode I parameters of fibre reinforced concrete

“…Alberti and his co-workers [19] also successfully conducted IA using FEM, based on the cohesive crack fracture concept instead of the smeared crack approach, and trilinear softening diagrams to characterise FRC reinforced with polyolefin fibres. More recently, Jepsen et al [20,21] proposed an IA methodology based on a global fitting procedure, relying on an analytical nonlinear hinge model to simulate the 3PNBBT response, in which an initial bilinear 𝜎 𝑐𝑡 − w is assumed and additional points are inserted sequentially in the relationship based on the error curve computed between the numerical and experimental response. However, this author uses an even discretisation of the experimental curve, which might require a high number of points, if the maximum measured w 𝑐𝑚𝑜𝑑 is relatively high, in order to obtain a good resolution of the main regions of the curve.…”

A Computationally Efficient Procedure for Calibrating Model Parameters Of Multiple Specimens

“…However, the sequential optimization of parameter subsets may lead to a local minimum rather than to the global one. Jepsen et al [22] proposed an adaptive method aimed at constructing a multi-linear softening curve. First, a bi-linear curve is used for the fitting, then edge points are sequentially added to the curve one by one in accordance with a refinement criterion.…”

Inverse analysis of traction-separation relationship based on sequentially linear approach

“…To this end, various approaches have been used, including the cracked hinge model, e.g. [5,6,7,8] or the finite element method (FEM), e.g [9]. The fitting is achieved by minimising an objective function using various optimisation techniques, such as the gradient methods with a line search [7], the simplex method [6] or the evolutionary algorithm including local neighbourhood attraction [9].…”

“…As the global optimization based methods [5,6,7,8,9] aim for matching the general trend of the measured load displacement relation, they are rather insensitive to its local irregularities resulting from local inhomogeneities along the crack path. Thus, the methods inherently "smooth out" the TS relationship, which then represents the overall cohesive property of the ligament material.…”