NumericalIRF Class

class openirf.NumericalIRF(M=array([], shape=(0, 0), dtype=float64), C=array([], shape=(0, 0), dtype=float64), K=array([], shape=(0, 0), dtype=float64))

OpenIRF Numerical IRF Class

Stores numerical model (M,C,K) for IRF calculation.

Constraints

• All matrices must have the same size

• M & K matrices must be added simultaneously

• Adding a C matrix is optional

Attributes

param M:

Mass matrix of numerical model.

type M:

ndarray

param C:

Damping matrix of numerical model.

type C:

ndarray

param K:

Stiffness matrix of numerical model.

type K:

ndarray

param t_vec:

Time vector corresponding to calculated IRFs.

type t_vec:

ndarray

param H_d:

Displacement IRF matrix.

type H_d:

ndarray

param H_v:

Velocity IRF matrix.

type H_v:

ndarray

param H_a:

Acceleration IRF matrix.

type H_a:

ndarray

C = array([], shape=(0, 0), dtype=float64)

H_a = array([], shape=(0, 0), dtype=float64)

H_d = array([], shape=(0, 0), dtype=float64)

H_v = array([], shape=(0, 0), dtype=float64)

K = array([], shape=(0, 0), dtype=float64)

M = array([], shape=(0, 0), dtype=float64)

add_MCK(M, K, C=None)

Add MCK matrices

This method allows to add MCK matrices to the class istance.

Constraints

• All matrices must have the same size

• M & K matrices must be added simultaneously

• Adding a C matrix is optional

Parameters

param M:

Mass matrix of numerical model.

type M:

ndarray, optional

param C:

Damping matrix of numerical model.

type C:

ndarray, optional

param K:

Stiffness matrix of numerical model.

type K:

ndarray, optional

calculate_IRF(t_step, t_len, exci_dofs=None, resp_dofs=None, ic_type='shifted_force')

Calculates a numerical IRF matrix

Numerically calculates an IRF matrix using Newmark time integration with the specified discrete time step size (t_step) for the specified length (t_len). The IRF matrix is calculated for force inputs at the dofs specified in exci_dofs and responses at the dofs specified in resp_dofs. The initial condition type used for the calculation can be specified with ic_type.

Supported initial condition types

• shifted_force (default): The Dirac impulse is applied as a force on the second time step.

• initial_force: The Dirac impulse is applied as a force on the first time step.

• initial_velocity: The Dirac impulse is applied as an initial system velocity.

Parameters

param t_step:

Discrete time step size (in seconds).

type t_step:

float

param t_len:

Length of calculated IRFs (in seconds).

type t_len:

float

param exci_dofs:

List of excitation dofs for which IRFs should be calculated.

type exci_dofs:

ndarray, optional

param resp_dofs:

List of response dofs for which IRFs should be calculated.

type resp_dofs:

ndarray, optional

param ic_type:

Initial condition type used for IRF calculation.

type ic_type:

string

t_vec = array([], dtype=float64)