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Mastering Mechanics 1: Using MATLAB 5

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Mastering Mechanics 1: Using MATLAB 5

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20 Aug 2002 (Updated )

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[forces]=fixedpin(x,s,m,a,EndSupport,E,I)
function [forces]=fixedpin(x,s,m,a,EndSupport,E,I)
%FIXEDPIN Redundant support moments and forces.
%   FIXEDPIN(X,SHEAR,MOMENT,PLACEMENT,L,E,I) will find the redundant moment
%   at the fixed support and the force supplied by any redundant pin 
%   supports along the length of the beam.
%
%   SHEAR is the shear acting along the beam, this should be created with 
%     the DIAGRAM routine.  It does not have to be summed into a single 
%     vector for use in the routine.
%   MOMENT is the moment acting along the beam, this should be only the
%     point moments created with the DIAGRAM routine.  It does not have to 
%     be suummed into a single vector for use in the routine.  It should 
%     not include the integral of the shear as created with the routine 
%     DIAGRAMINTEGRAL.
%   PLACEMENT is a vector with the location of every pin support.
%   L is the length of the beam, may extend beyond the last pin support.
%   E is the Young's modulus.
%   I is the area moment of inertia of the beam cross section.
%
%   See also DIAGRAM, FIXEDFIXED, PINPIN.

%   Details are to be found in Mastering Mechanics I, Douglas W. Hull,
%   Prentice Hall, 1998

%   Douglas W. Hull, 1998
%   Copyright (c) 1998-99 by Prentice Hall
%   Version 1.00


b=EndSupport-a;

[ShearRows, ShearCols]=size(s);
[MomentRows, MomentCols]=size(m);

if ShearRows>1
  Shear=sum(s);
else
  Shear=s;
end

if MomentCols==1 %just sent a dummy
  Moment=diagramintegral(x,Shear);
else
  m(MomentRows+1,:)=diagramintegral(x,Shear);
  Moment=sum(m);
end

[d sl]=displace(x,Moment,['place' 'place'],[0 EndSupport],E,I);

Deltas(1)=-interpolate(x,sl,0);
coefs=2*EndSupport^2/(6*E*I*EndSupport);

if a~=0
  i=1;
  for gapli=2:length(a)+1;
    Deltas(gapli)=-interpolate(x,d,a(gapli-1));
    i=i+1;
  end
  SubSca=2*EndSupport^2;
  SubCol=(a.*((a.^2)-(3*EndSupport*a)+(2*EndSupport^2)))';
  SubRow=(a.*b.*(EndSupport+b));
  SubMat=makepins(a,EndSupport,0);
  coefs=[SubSca SubRow; SubCol SubMat]/(6*E*I*EndSupport);
end

forces=inv(coefs)*Deltas';

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