get weaver to match

Author: PetrKryslUCSD

examples/weaver_1.py

@@ -15,6 +15,7 @@
 from pystran import section
 from pystran import plots
 from pystran import beam
+from pystran import rotation
 
 # US customary units, inches, pounds, seconds
 L = 120.0
@@ -39,18 +40,22 @@
 model.add_support(m["joints"][3], model.CLAMPED)
 model.add_support(m["joints"][4], model.CLAMPED)
 
-xz_vector = [1, 0, 0]
+xz_vector = [0, 0, 1]
 sect_1 = section.beam_3d_section(
     "sect_1", E=E, G=G, A=A, Ix=Ix, Iy=Iy, Iz=Iz, J=J, xz_vector=xz_vector
 )
-xz_vector = [0, 1, 0]
+xz_vector = [0, 0, 1]
 sect_2 = section.beam_3d_section(
     "sect_2", E=E, G=G, A=A, Ix=Ix, Iy=Iy, Iz=Iz, J=J, xz_vector=xz_vector
 )
+xz_vector = rotation.rotate(m["joints"][2], m["joints"][4], [0, 1, 0], 90)
+sect_3 = section.beam_3d_section(
+    "sect_3", E=E, G=G, A=A, Ix=Ix, Iy=Iy, Iz=Iz, J=J, xz_vector=xz_vector
+)
 
-model.add_beam_member(m, 1, [1, 2], sect_2)
-model.add_beam_member(m, 2, [3, 1], sect_1)
-model.add_beam_member(m, 3, [2, 4], sect_2)
+model.add_beam_member(m, 1, [1, 2], sect_1)
+model.add_beam_member(m, 2, [3, 1], sect_2)
+model.add_beam_member(m, 3, [2, 4], sect_3)
 
 model.add_load(m["joints"][1], model.U1, F)
 model.add_load(m["joints"][2], model.U2, -P)

pystran/rotation.py

@@ -5,6 +5,7 @@
 
 from math import pi, cos, sin
 import numpy
+from pystran.geometry import delt, len
 
 
 def rotmat3(rotvec):
@@ -34,3 +35,14 @@ def rotmat3(rotvec):
         R[1, 1] += ca
         R[2, 2] += ca
     return R
+
+
+def rotate(i, j, v, angleindegrees):
+    """
+    Rotate a 3D vector `v` by an angle about the unit vector defined by joints `i`
+    and `j`.
+    """
+    ci, cj = i["coordinates"], j["coordinates"]
+    uv = delt(ci, cj) / len(ci, cj)
+    angle = angleindegrees * pi / 180.0
+    return rotmat3(uv * angle).dot(numpy.array(v))