A smooth unloading–reloading approach for the nonlinear finite element analysis of quasi-brittle materials. (February 2016)

• Record Type: Journal Article
• Authors: Alnaas, W.F.; Jefferson, A.D.
• Is Part Of: Engineering fracture mechanics. Volume 152(2016)
• Page Start: 105
• Page End: 125
• Publication Date: 2016-02
• Subjects: Damage -- Constitutive model -- Non-linear finite element analysis -- Quasi-brittle materials; Fracture mechanics -- Periodicals; Rupture, Mécanique de la -- Périodiques; Fracture mechanics; Periodicals; 620.112605
• DOI: 10.1016/j.engfracmech.2015.04.018
• Languages: English
• ISSNs: 0013-7944

Abstract

Highlights: We developed an incremental-iterative method for non-linear FE analysis of quasi-brittle materials. Smooth unloading–reloading (SUR) and predictive-SUR approaches are proposed. We explored the convergences characteristics of an isotropic damage model. Results show that both proposed approaches are robust and improved the convergence properties significantly. Abstract: This paper presents a new method for improving the robustness and convergence characteristics of a finite element damage model for quasi-brittle materials. In this method, a smooth unloading–reloading function (SUR) is employed to compute an approximate tangent matrix in a Newton type solution procedure. A new method is also presented for predicting a converged value of the damage parameter. The performance of the new methods are assessed using a range of idealised quasi-brittle specimens. Results show that the new SUR approaches are robust and result in considerable savings relative to solutions obtained with a secant unloading–reloading function.