f_ft.m

关于高层建筑强风条件下风压系数计算

function F_t = F_Ft(Cp_tr,V)
global  flnTaps  taps  Ntaps  Npoints
% This function calculates the wind load matrix, F_t, [Ntaps x Npoints], for dynamic MDOF system
%%%%%%%%%%%%%%%%% Pressure tap information : flnTaps, Page 2, [Ntaps x 5] %%%%%%%%%%%%%%%%%%%%
% Load flnTaps and check for errors
clear fid; fid=fopen(flnTaps);
if fid == -1
    errordlg('Unable to open ''flnTaps'' - Page 2')
    error   ('Unable to open ''flnTaps'' - Page 2')
end
fclose(fid); clear fid;
[taps]=[]; load (flnTaps)   
if isempty(taps)==1
    errordlg('Variable ''taps'' not defined. See flnTaps on Page Two')
    error   ('Variable ''taps'' not defined. See flnTaps on Page Two')
end
if size(taps,1) ~= Ntaps | size(taps,2) ~= 5
    errordlg('Variable ''taps'' not properly sized. (Ntaps x 5)')
    error   ('Variable ''taps'' not properly sized. (Ntaps x 5)')
end

A_t = taps(:,5);              % Tributary areas in last column of 'taps'

%%%%%%%%%%%%%%%% Calculate the wind load matrix, F_t, [Ntaps x Npoints] %%%%%%%%%%%%%%%%%%%%%
F_t = zeros(Ntaps,Npoints);   % Initialize the wind forces array 
% Change the following lines to accomodate the proper F_t
% In all cases: const*[Ntaps x Ntaps]*[Ntaps x time]
% 1a. Cp_tr contains pressure coefficients & the units of F_t are kN 
%     F_t         = (0.613*V^2/1000) * diag(A_t) * Cp_tr;     
% 1b. Cp_tr contains pressure coefficients & the units of F_t are N 
      F_t         = (0.613*V^2) * diag(A_t) * Cp_tr;  
% 2. Cp_tr contains pressures in N/m^2; the unit of F_t are N
%    F_t         = diag(A_t) * Cp_tr; 
% 3. Cp_tr contains forces in N; the units of F_t are N
%    F_t         =  Cp_tr;