C Library#

Data Structures#

//

struct sdof_alpha#

Parameters for the generalized alpha method.

double alpha_m#

WBZ alpha parameter

double alpha_f#

HHT alpha parameter

double gamma#

Newmark’s \(\gamma\) parameter

double beta#

Newmark’s \(\beta\) parameter

struct sdof_peaks#

Struct to return peak response quantities by value.

double max_displ#

Peak displacement

double max_veloc#

Peak velocity

double max_accel#

Peak acceleration

Integration#

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int sdof_integrate(struct sdof_alpha *conf, double M, double C, double K, double scale, int n, double *p, double dt, double *response)#

Main linear integrator.

Parameters:

  • conf (struct sdof_alpha*) – Struct holding integration parameters.

  • load (const double[n]) – Pointer to excitation series

  • n (const int) – size of excitation series

  • dt (const double) – Time step of excitation data.

  • M (double) – Mass.

  • C (double) – Damping.

  • K (double) – Stiffness

  • response (double[n][3]) – Pointer to the beginning of an n x 3 array of doubles. displacement at i: response[i][0] velocity at i: response[i][1] acceleration at i: response[i][2]

Note

The first row of the response array is expected to be initialized, ie

response[0][0] = u0;
response[0][1] = v0;
int sdof_integrate_plastic(struct sdof_alpha *conf, double M, double C, double K, double scale, int n, double *p, double dt, double *response)#

Elastic-perfectly plastic

  • Simo, J.C. and Hughes, T.J.R. (2000) Computational inelasticity. Corr. 2. print. New York Heidelberg Berlin: Springer (Interdisciplinary applied mathematics Mechanics and materials, 7).

Parameters:

  • Fy (double) – Yield force

  • a (double) – Kinematic hardening ratio

UR_INCR#

Integrate a linear system, tracking only peak values.

int sdof_integrate_peaks(struct sdof_alpha *conf, double M, double C, double K, double scale, int n, double *p, double dt, struct sdof_peaks *response)#

Integrate a linear system, tracking only peak values.

struct sdof_peaks sdof_integrate_peaks_2(struct sdof_alpha *conf, double M, double C, double K, double scale, int n, const double *p, double dt)#

Alternative implementation to return an sdof_peaks struct by value. This is used in _spectrum.c .

Response Spectra#

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int sdof_spectrum(struct sdof_alpha *conf, const double *load, const int n, const double dt, const double t_min, const double t_max, const int n_periods, const double damp, int n_threads, struct sdof_peaks *response)#

Threaded response spectrum over regularly spaced periods.

This function spawns n_threads threads to perform a total of n_periods integrations over regularly spaced periods.

Parameters:

  • conf (struct sdof_alpha*) –

    .

  • load (const double[n]) – Pointer to excitation series

  • n (const int) – size of excitation series

  • dt (const double) – Time step of excitation data.

  • t_min (const double) – Start period

  • t_max (const double) – End period

  • n_periods (const int) – Number of periods to integrate.

  • damp (const double) –

    .

  • n_threads (int) –

    .

  • *response (struct sdof_peaks) –