Defining the Geometry#

Based on the figure:


The geometry can be defined using \(H\), \(R_1\) and \(\alpha\), for example, or any other combination (like \(L\), \(H\), \(R_1\)) of the geometric parameters that will allow the complete definition of the cone / cylinder geometry.


from compmech.conecyl import ConeCyl

cc = ConeCyl()
cc.r1 = 400
cc.r2 = 200
cc.H = 200

Defining the Laminate and Material Properties#

The compmech.composite module is used to calculate the laminate properties given the stacking sequence, the thicknesses and the material properties.

The stacking sequence is passed using a container (list or tuple) with the orientations of each ply, from inwards to outwards:

cc.stack = [0, 0, -45, +45, -30, +30]

The ply thickness is passed using a single value when all the plies have the same thickness or using a container with the thickness of each ply:

cc.plyt = 0.125


cc.plyts = [0.125, 0.125, 0.1, 0.1, 0.101, 0.101]

The material properties are given using a tuple:

\[(E_{11}, E_{22}, \nu_{12}, G_{12}, G_{13}, G_{23})\]

where \(E_{11}\) is the elastic modulus along the direction 1 of the ply, \(E_{22}\) the modulus along the direction 2, \(\nu_{12}\) the Poisson’s ratio and \(G_{12}\), \(G_{13}\), \(G_{23}\) the shear modules.


cc.laminaprop = (123.55e3 , 8.708e3,  0.319, 5.695e3, 5.695e3, 5.695e3)

This will assume the same material properties for each ply. When different properties must be used the user must supply the laminaprops container.


prop1 = (123.55e3 , 8.708e3,  0.319, 5.695e3, 5.695e3, 5.695e3)
prop2 = (100.2e3 , 4.2e3,  0.2, 5.1e3, 5.1e3, 5.1e3)
prop3 = (100.2e3 , 4.2e3,  0.2, 5.1e3, 5.1e3, 5.1e3)
cc.laminaprops = [prop1, prop1, prop2, prop2, prop3, prop3]

Linear Static Analysis#

The static analysis is executed using the compmech.conecyl.ConeCyl.static() method. The following example will give an overview of the main steps needed for a linear static analysis.

Defining the geometry:

>>> cc.laminaprop = (123.55e3 , 8.708e3,  0.319, 5.695e3, 5.695e3, 5.695e3)
>>> cc.stack = [0, 0, 19, -19, 37, -37, 45, -45, 51, -51]
>>> cc.r2 = 250.
>>> cc.H = 510.
>>> cc.plyt = 0.125
>>> cc.alphadeg = 30.

Defining the model and boundary conditions:

>>> cc.model = 'fsdt_donnell_bc1'
>>> cc.bc = 'cc1'

Defining if the analysis is displacement or load controlled by changing the boolean parameters pd (prescribed displacement):

  • prescribed displacement for compression: cc.pdC

  • prescribed displacement for torsion: cc.pdT

  • prescribed load asymmetry cc.pdLA

Applying the axial compression, pressure, torsion and the single-perturbation loads:

>>> cc.Fc = 10000.
>>> cc.T = 100000.
>>> cc.P = -0.01
>>> cc.add_SPL(10.)
>>> cc.add_SPL(4.)

Defining the number of terms in the approximation functions:

>>> cc.m1 = 80
>>> cc.m2 = 40
>>> cc.n2 = 40

Running the analysis:

>>> cc.static()

The results are stored in the cs list, and for a linear static analysis only one entry exists. Plotting the results:

>>> cc.plot(cc.cs[0], vec='w')

Static Analysis#

where NLgeom is a flag telling whether or not a geometric non-linear analysis is to be performed.

The solution is stored in the cs attribute, which consists of a list of 1-D np.ndarray objects. For a linear analysis this list will contain only one entry while for a non-linear analysis it will contain one entry for each iteration needed up to the convergence or up to the termination criterion. To access the last result:

solution = cc.cs[-1]

The displacement field can be plotted, for example:

cc.plot(solution, vec='w', filename='my_output.png')

Non-Linear Analysis#

Using NLgeom=True in a static analysis will run a geometrically non-linear analysis. Many attributes of the ConeCyl object are used to control the non-linear analysis (see ConeCyl.static()).

The converged increments used along the non-linear analysis are stored in the increments attribute and the corresponding solutions stored in the cs attribute (a list of 1-D np.ndarray objects).