www.pudn.com > WebsiteCode.zip > shearsafetyfact.m, change:2008-07-24,size:1633b


function c = shearsafetyfact(design) 
% c = shearsafetyfact(design) 
% 
% Calculates shear safety factor 
% 
% Copyright 2007 A Sobester 
% 
% This program is free software: you can redistribute it and/or modify  it 
% under the terms of the GNU Lesser General Public License as published by 
% the Free Software Foundation, either version 3 of the License, or any 
% later version. 
%  
% This program is distributed in the hope that it will be useful, but 
% WITHOUT ANY WARRANTY; without even the implied warranty of 
% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser 
% General Public License for more details. 
%  
% You should have received a copy of the GNU General Public License and GNU 
% Lesser General Public License along with this program. If not, see 
% <http://www.gnu.org/licenses/>. 
 
% ********* DESIGN VARIABLES ******** 
% Wire diameter 
d = 0.5 + 6.5*design(1); 
 
% Spring index 
i = 4 + 12*design(2); 
 
% Inter-coil distance coefficient 
% kdelta = 0.1 + design(3); 
 
 
% ******** PROBLEM DEFINITION ******* 
 
% Maximum and minimum load 
Fmin = 40; Fmax = 500; 
 
% Wire material coefficients 
C3 = 0.625e5; 
A1 = -0.19; 
 
% Stress factor (Wahl factor) 
kw = (4*i-1)/(4*i+4) + 0.615/i; 
 
% Maximum/minimum shear stress [MPa] 
tautmax = 8*kw*i*Fmax/(pi*d^2); 
tautmin = 8*kw*i*Fmin/(pi*d^2); 
 
% Amplitude/mean of the loading cycle [MPa] 
taua = (tautmax - tautmin)/2; 
taum = (tautmax + tautmin)/2; 
 
% Yield shear strength [MPa] 
Sys = C3*(1/25.4^2)*4.448*(d/25.4)^A1; 
 
% Yield safety factor 
SFy = Sys/(taua+taum); 
 
% ********* CONSTRAINT ************** 
c = 1.05 - SFy;