transform

Documentation

Index

• func Atma(t1, t2, t3, t4, t5, t6, t7, t8, t9 float64, m [][]float64, r1, r2 float64)
• func CoordTrans(xyz []femath.Vec3, L float64, n1, n2 int, ...)

Functions

func Atma

func Atma(t1, t2, t3, t4, t5, t6, t7, t8, t9 float64, m [][]float64, r1, r2 float64)

Atma performs the coordinate transformation from local to global 6jan96 includes effects of a finite node radii, r1 and r2. 9dec04 a is the transformation matrix based off of t1...t9 m is a 12x12 matrix that gets transformed. This function is only special in that it creates the transition matrix. Need to replace the lame matrix multiplication loops with a function call.

func CoordTrans

func CoordTrans(xyz []femath.Vec3, L float64, n1, n2 int, t1, t2, t3, t4, t5, t6, t7, t8, t9 *float64, p float64)

CoordTrans calculates the 9 elements of the block-diagonal 12-by-12 coordinate transformation matrix, t1, t2, ..., t9. These coordinate transformation factors are used to: * transform frame element end forces from the element (local) coordinate system to the structral (global) coordinate system. * transfrom end displacements from the structural (global) coordinate system to the element (local) coordinate system, * transform the frame element stiffness and mass matrices from element (local) coordinates to structral (global) coordinates. Element matrix coordinate transformations are carried out by function ATMA in framefea.c Currently coordinate transformations do not consider the effect of finite node sizes ... this needs work, and could require a substantial re-write of much of the code. Currently the effect of finite node sizes is used only in the calculation of the element stiffness matrices.

COORDTRANS -  evaluate the 3D coordinate transformation coefficients 1dec04
Default order of coordinate rotations...  typical for Y as the vertical axis
1. rotate about the global Z axis
2. rotate about the global Y axis
3. rotate about the local  x axis --- element 'roll'
If Zvert is defined as 1, then the order of coordinate rotations is typical
for Z as the vertical axis
1. rotate about the global Y axis
2. rotate about the global Z axis
3. rotate about the local  x axis --- element 'roll'
Q=TF;   U=TD;   T'T=I;   Q=kU;   TF=kTD;   T'TF=T'kTD;   T'kT = K;   F=KD
vec3 *xyz, 			// XYZ coordinate of all nodes
double L, 			// length of all beam elements
int n1, int n2, 		// node connectivity
double *t1, double *t2, double *t3, double *t4, double *t5,
double *t6, double *t7, double *t8, double *t9, // coord transformation
float p				// the roll angle (radians)