spaceframeelementlumpedmass.m

有限元程序的matlab工具包

function y = SpaceFrameElementLumpedMass(Rou,A,Io,node_axis1,node_axis2)
x1=node_axis1(1);y1=node_axis1(2);z1=node_axis1(3);
x2=node_axis2(1);y2=node_axis2(2);z2=node_axis2(3);
L = sqrt((x2-x1)*(x2-x1) + (y2-y1)*(y2-y1) + (z2-z1)*(z2-z1));
w1=Rou*A*L/2;
w2=Io;
mprime=zeros(12,12);
mprime(1,1)=w1;
mprime(2,2)=w1;
mprime(3,3)=w1;
mprime(4,4)=w2
mprime(7,7)=w1;
mprime(8,8)=w1;
mprime(9,9)=w1;
mprime(10,10)=w2;
if x1 == x2 & y1 == y2
   if z2 > z1
      Lambda = [0 0 1 ; 0 1 0 ; -1 0 0];
   else
      Lambda = [0 0 -1 ; 0 1 0 ; 1 0 0];
   end
else
   CXx = (x2-x1)/L;
	CYx = (y2-y1)/L;
	CZx = (z2-z1)/L;
	D = sqrt(CXx*CXx + CYx*CYx);
	CXy = -CYx/D;
	CYy = CXx/D;
	CZy = 0;
	CXz = -CXx*CZx/D;
	CYz = -CYx*CZx/D;
	CZz = D;
	Lambda = [CXx CYx CZx ; CXy CYy CZy ; CXz CYz CZz];
end
R = [Lambda zeros(3) zeros(3) zeros(3) ; 
   zeros(3) Lambda zeros(3) zeros(3) ;
   zeros(3) zeros(3) Lambda zeros(3) ;
   zeros(3) zeros(3) zeros(3) Lambda];
y = R'*mprime*R;