HOTINT - A C++ ENVIRONMENT FOR THE SIMULATION OF MULTIBODY DYNAMICS SYSTEMS AND FINITE ELEMENTS

A multibody dynamics system simulation code HOTINT is presented. The software has been developed for research purpose during the past ten years and has some consistently different features as compared to other commercial and research software. The simulation software originates from a pure time integration code that was able to solve differential alge- braic equations of motion. Five years ago, a multibody system kernel has been attached to the time integration code and a 3D visualization engine has been developed. At the current stage the software is able to solve dynamic or static problem consisting of a general system of ob- jects. The objects are represented by classical first or second order differential equations, al- gebraic equations and inequalities, which all of them can be nonlinear. The general kernel is not only able to manage the equations, but also to handle data of the objects for direct editing and storage in a file, as well as graphical representation of the system and export of resulting quantities of the system. The solver contains specific solvers for open and closed loop multi- body systems, all of them based on redundant multibody formulations. The solver is especially adapted to second order differential equations and does not intend to factorize the mass ma- trix of the system in any time step. The paper will show some details on the hierarchy of the code and introduce into some concepts, which might be interesting for other developers. It will also be shown what is necessary to add a new object, such as a mechanical body or a constraint condition. While the code is not available open source, a part of the software is available as a freeware and can be downloaded as well as some examples that have been solved with the software.