Dear FEAP users and developers:
first at all, my more sincere congratulations because the idea of creating a user forum for FEAP. Although I am novice in using FEAP (a code which I have a sincere intention to learn...), I have long experience in implementing finite element methods both in academia and industry. This post is my first contribution to this community and it is a pleasure for me to suggest two books on computational plasticity, both written by world authorities on the subject, and which have been rather useful for my understanding of general principles and algorithms and the implementation of material models:
Inelastic Analysis of Solids and Structures
M. Kojic, K. J. Bathe
Springer (2005)
Computational Methods for Plasticity. Theory and Applications
E. A. de Souza Neto, D. Peric, D. R. J. Owen
Wiley (2008)
The former is notable for exposing the Governing Parameter Method. This method developed by both authors, basically consists of reducing the resolution of the governing equations to solving a equation of a single variable. This function is often monotone decreasing), with a resolution very robust. This methodology is very different from the traditional method discussed in other texts where are used Newton methods with several variables whose convergence is very difficult (almost miraculous!!!). Interestingly, incremental approaches (rate formulations) are not described.
The later is of a much more general approach. In particular, apart from addressing the incremental and hyperelastic formulations in plasticity, also addresses element formulations especially useful for incompressibility: mixed formulations and F-bar formulations (first time in a textbook). Worth noting the description of algorithms in principal values, which they apply to various geomaterial models. These authors were pioneers in applying this methodology in a effective way for multisurface plasticity.
In short, both books are superb...
I am convinced them will be very useful for everyone interested in the implementation of constitutive models in FEAP.
Antonio
Madrid, Spain
PD: sorry my English faults.