Note

Go to the end to download the full example code

生成和提取旋转位移#

在本例中，我们将展示如何处理壳体和旋转位移。

并非所有单元类型都有旋转自由度，但一般来说，”壳” 单元都有。在本例中，我们创建一个厚度为 0.1 的正方形外壳，然后将其弯曲，产生旋转位移。

随后，我们绘制累积主应力图，并使用 ansys.mapdl.core.inline_functions.Query 提取正方形四个角的旋转位移精确值。

# start MAPDL and enter the pre-processing routine
from ansys.mapdl.core import launch_mapdl

mapdl = launch_mapdl()
mapdl.prep7()

*** MAPDL - ENGINEERING ANALYSIS SYSTEM  RELEASE 2023 R1          23.1     ***
 Ansys Mechanical Enterprise
 20120530  VERSION=WINDOWS x64   22:04:48  JAN 26, 2024 CP=      0.750





          ***** MAPDL ANALYSIS DEFINITION (PREP7) *****

Mesh Setup#

在本例中，我们创建了一个简单的二维正方形，尺寸为 1 x 1，并赋予其 SHELL181 单元类型，因为该类型具有旋转自由度。接下来我们

  • 给出该材料的弹性模量为 2e5 (EX)

  • 将材料的主要泊松比定为 0.3 (PRXY)

  • 将截面类型设置为 “SHELL”

  • 将厚度设置为 0.1

  • 将单元大小设置为 0.2

  • 划分网格

  • 绘制模型

mapdl.et(1, "SHELL181")
mapdl.mp("EX", 1, 2e5)
mapdl.mp("PRXY", 1, 0.3)
mapdl.rectng(0, 1, 0, 1)
mapdl.sectype(1, "SHELL")
mapdl.secdata(0.1)
mapdl.esize(0.2)
mapdl.amesh("all")
mapdl.eplot()
04 rotational displacement

Applying Boundary Conditions#

  • 进入求解层

  • 将分析类型设为 STATIC 。

  • 约束 x = 0 节点的所有自由度

  • 在 x = 1 处施加 uz = -0.1 的位移

  • 选择所有节点

  • 求解模型

mapdl.run("/SOLU")
mapdl.antype("STATIC")
mapdl.nsel("s", "loc", "x", 0)
mapdl.d("all", "all")
mapdl.nsel("s", "loc", "x", 1)
mapdl.d("all", "uz", -0.1)
mapdl.allsel("all")
mapdl.solve()

*** NOTE ***                            CP =       0.812   TIME= 22:04:49
 The automatic domain decomposition logic has selected the MESH domain
 decomposition method with 2 processes per solution.

 *****  MAPDL SOLVE    COMMAND  *****

 *** NOTE ***                            CP =       0.812   TIME= 22:04:49
 There is no title defined for this analysis.

 *** SELECTION OF ELEMENT TECHNOLOGIES FOR APPLICABLE ELEMENTS ***
                ---GIVE SUGGESTIONS ONLY---

 ELEMENT TYPE         1 IS SHELL181. IT IS ASSOCIATED WITH ELASTOPLASTIC
 MATERIALS ONLY. KEYOPT(8)=2 IS SUGGESTED AND KEYOPT(3)=2 IS SUGGESTED FOR
 HIGHER ACCURACY OF MEMBRANE STRESSES; OTHERWISE, KEYOPT(3)=0 IS SUGGESTED.



 *** MAPDL - ENGINEERING ANALYSIS SYSTEM  RELEASE 2023 R1          23.1     ***
 Ansys Mechanical Enterprise
 20120530  VERSION=WINDOWS x64   22:04:49  JAN 26, 2024 CP=      0.812





                       S O L U T I O N   O P T I O N S

   PROBLEM DIMENSIONALITY. . . . . . . . . . . . .3-D
   DEGREES OF FREEDOM. . . . . . UX   UY   UZ   ROTX ROTY ROTZ
   ANALYSIS TYPE . . . . . . . . . . . . . . . . .STATIC (STEADY-STATE)
   GLOBALLY ASSEMBLED MATRIX . . . . . . . . . . .SYMMETRIC

 *** NOTE ***                            CP =       0.812   TIME= 22:04:49
 Present time 0 is less than or equal to the previous time.  Time will
 default to 1.

 *** NOTE ***                            CP =       0.812   TIME= 22:04:49
 The conditions for direct assembly have been met.  No .emat or .erot
 files will be produced.



     D I S T R I B U T E D   D O M A I N   D E C O M P O S E R

  ...Number of elements: 25
  ...Number of nodes:    36
  ...Decompose to 2 CPU domains
  ...Element load balance ratio =     1.083


                      L O A D   S T E P   O P T I O N S

   LOAD STEP NUMBER. . . . . . . . . . . . . . . .     1
   TIME AT END OF THE LOAD STEP. . . . . . . . . .  1.0000
   NUMBER OF SUBSTEPS. . . . . . . . . . . . . . .     1
   STEP CHANGE BOUNDARY CONDITIONS . . . . . . . .    NO
   PRINT OUTPUT CONTROLS . . . . . . . . . . . . .NO PRINTOUT
   DATABASE OUTPUT CONTROLS. . . . . . . . . . . .ALL DATA WRITTEN
                                                  FOR THE LAST SUBSTEP


 SOLUTION MONITORING INFO IS WRITTEN TO FILE= file.mntr

 *** NOTE ***                            CP =       0.828   TIME= 22:04:49
 Predictor is ON by default for structural elements with rotational
 degrees of freedom.  Use the PRED,OFF command to turn the predictor
 OFF if it adversely affects the convergence.


 Range of element maximum matrix coefficients in global coordinates
 Maximum = 7487.02512 at element 18.
 Minimum = 7487.02512 at element 8.

   *** ELEMENT MATRIX FORMULATION TIMES
     TYPE    NUMBER   ENAME      TOTAL CP  AVE CP

        1        25  SHELL181      0.000   0.000000
 Time at end of element matrix formulation CP = 0.828125.

 DISTRIBUTED SPARSE MATRIX DIRECT SOLVER.
  Number of equations =         174,    Maximum wavefront =     42

  Process memory allocated for solver              =     0.281 MB
  Process memory required for in-core solution     =     0.270 MB
  Process memory required for out-of-core solution =     0.270 MB

  Total memory allocated for solver                =     0.518 MB
  Total memory required for in-core solution       =     0.497 MB
  Total memory required for out-of-core solution   =     0.497 MB

 *** NOTE ***                            CP =       0.828   TIME= 22:04:49
 The Distributed Sparse Matrix Solver is currently running in the
 in-core memory mode.  This memory mode uses the most amount of memory
 in order to avoid using the hard drive as much as possible, which most
 often results in the fastest solution time.  This mode is recommended
 if enough physical memory is present to accommodate all of the solver
 data.
 Distributed sparse solver maximum pivot= 29948.1005 at node 31 UX.
 Distributed sparse solver minimum pivot= 0.248519178 at node 2 ROTZ.
 Distributed sparse solver minimum pivot in absolute value= 0.248519178
 at node 2 ROTZ.

   *** ELEMENT RESULT CALCULATION TIMES
     TYPE    NUMBER   ENAME      TOTAL CP  AVE CP

        1        25  SHELL181      0.000   0.000000

   *** NODAL LOAD CALCULATION TIMES
     TYPE    NUMBER   ENAME      TOTAL CP  AVE CP

        1        25  SHELL181      0.000   0.000000
 *** LOAD STEP     1   SUBSTEP     1  COMPLETED.    CUM ITER =      1
 *** TIME =   1.00000         TIME INC =   1.00000      NEW TRIANG MATRIX


 *** MAPDL BINARY FILE STATISTICS
  BUFFER SIZE USED= 16384
        0.062 MB WRITTEN ON ASSEMBLED MATRIX FILE: file0.full
        0.312 MB WRITTEN ON RESULTS FILE: file0.rst

Plotting Stresses#

  • 提取结果

  • 绘制累积 (0) 等效应力 (SEQV) 图

  • 将 colormap 设置为 ‘plasma’，因为它在感知上是一致的

  • 显示位移，以便我们看到任何变形

result = mapdl.result
result.plot_principal_nodal_stress(
    0, "SEQV", show_edges=True, cmap="plasma", show_displacement=True
)
04 rotational displacement

Extracting Rotational Displacements#

q = mapdl.queries

node1 = q.node(0, 0, 0)
node2 = q.node(0, 1, 0)
node3 = q.node(1, 0, 0)
node4 = q.node(1, 1, 0)

nodes = [node1, node2, node3, node4]

rotations = [(q.rotx(n), q.roty(n), q.rotz(n)) for n in nodes]

message = f"""
(0,1) B _________ C (1,1)
       |         |
       |         |
       |         |
       |_________|
(0,0) A           D (1,0)

N | (x_rot_disp, y_rot_disp, z_rot_disp)
--|------------------------------------
A | {rotations[0][0]:11.6f},{rotations[0][1]:11.6f},{rotations[0][2]:11.6f}
B | {rotations[1][0]:11.6f},{rotations[1][1]:11.6f},{rotations[1][2]:11.6f}
C | {rotations[2][0]:11.6f},{rotations[2][1]:11.6f},{rotations[2][2]:11.6f}
D | {rotations[3][0]:11.6f},{rotations[3][1]:11.6f},{rotations[3][2]:11.6f}

"""

print(message)

(0,1) B _________ C (1,1)
       |         |
       |         |
       |         |
       |_________|
(0,0) A           D (1,0)

N | (x_rot_disp, y_rot_disp, z_rot_disp)
--|------------------------------------
A |    0.000000,   0.000000,   0.000000
B |    0.000000,   0.000000,   0.000000
C |   -0.000996,   0.155360,   0.000000
D |    0.000996,   0.155360,   0.000000

Stop mapdl#

mapdl.exit()

Total running time of the script: (0 minutes 1.320 seconds)