dxxdt.m

结构力学中的有限元例子,包含了7个分类文件夹

function xd = dxxdt(t,x)

% x - state vector;  x = [y ; y'] 
% t - time step

global dof h Mi C K zdd delta_t

ku = max(1,floor(t/delta_t));                    % index
zddnow = zdd(ku) + (zdd(ku+1)-zdd(ku))*(t/delta_t - ku);

displ = x(1:dof);                                % displacements
veloc = x(dof+1:2*dof);                          % velocities
accel = -Mi*(C*veloc + K*displ) - h*zddnow;   % acceleration

xd = [ veloc; accel ];                           % x' = [y'; y"]