A frontal solver tuned for fully coupled non-linear hygro-thermo-mechanical problems

Solving fully coupled non-linear hygro-thermo-mechanical problems relative to the behaviour of concrete at high temperatures using monolithic models is nowadays a very interesting and challenging computational problem. These models require an extensive use of computational resources, such as main memory and computational time, due to the great number of variables and the numerical characteristics of the coe cients of the linear systems involved. In this paper, a number of di erent variants of a frontal solver used within HITECOSP, an application developed within the BRITE Euram III ‘HITECO’ EU project, to solve multiphase porous media problems, are presented and evaluated with respect to their numerical accuracy and performance. When developing the variants, several optimization techniques have been adopted, such as data structure, cache and branches optimizations. Speci cally, numerical accuracy has been evaluated using a modi ed componentwise backward error analysis. The main result of this work is a new solver which is both much faster and more accurate than the original one. Speci cally, the code runs over ve times faster and numerical errors are reduced by up to three orders of magnitude