modali

Structural dynamics solver based on modal integration
Adrien Crovato and Huseyin Guner ULiege, 2019-2020

Description

modali is a python code allowing to compute the response of a structure subjected to an excitation based on its modal charasteristics.
modali v2 and up is compatible with python 3, while previous versions are compatible with python2.

modali solves the following equation:
M_q q_ddot + C_q q_dot + K_q q = f_q,
where M_q, C_q and K_q are the modal mass, damping and stiffness matrices, q is the modal displacements vector and f_q is the modal forces vector. The modal displacements are then multiplied by the mode shape matrix to get the physical displacements.

Features

• Static solver: solves K_q q = f_q for a diagonal stiffness matrix
• Dynamic integrator: solves the full equation with Runge-Kutta order 4-5

Usage

modali has been designed to be used with CUPyDO but also works in standalone.
Example/test cases are given under tests, they can be run with

python run.py tests/testname.py

For coupled cases, plese refer to CUPyDO repository.

Input

The following inputs are required to create a case:

• Initial modal displacements, velocities and loads (can be 0)
• Modal matrices formatted as numpy matrices
• Mode shapes in a .csv file. Each line of the file should contain an index, the x, y and z coordinates of a physical node, and the x, y, z coordinates of the m first mode shapes.
• Extractor index list (cannot be empty!)