Interface for Plane Strain cylinder Model:

The geometric input conditions for the cylinder are entered in the top right table. These include the internal radius, tube length, tape or tow with, autofrettage radius (set to zero if not used) the position x, and whether the cylinder is open ended or closed.

The position x value is used to define a specific location of interest along the length of the tube. It is not used in the solver but used as a position marker to relate the laminate definition with respect to the end of a tube. It is useful when creating a tube where the laminate may vary along the length of a tube.  It is used when exporting a series of laminates to a third party FEA solver.

The open (0) or closed (1) condition specifies where the ends of the tube are open or closed. The end cap pressures are added to the axial stress component of loading when the cylinder is closed.

The Loading conditions include internal pressure Pi, external pressure Po, axial force Fa, torsion Jz, winding tension Fw, mandrel temperature Tm, process temperature Tp, and operating temperature To.

The winding tension applied the the specified tow width thus adding a stress in each laminate ply during placement. The tension is orientated from the principle (ply) direction to the global (tube) direction in the solution.

There are four options when applying temperature to the solution, use process temperatures, transient solution, process temperatures and transient solution or delta T defined in the laminate section. The following sections describe each option.

Using Process Temperatures 

To model stresses from processing select this option and then define the mandrel temperature and process temperature. Select the final (operating) temperature to be room temperature to just observe stresses during manufacture.

The mandrel temperature is the process temperature applied to the first ply. This first ply may be a steel tube used as the placement tool. This temperature may differ from the process temperature through active heating or cooling.

The process temperature is the stress free temperature at which the laminate is placed. If the material undergoes curing then the stress free temperature would be the glass transition temperature of the resin.

The operating temperature is the temperature the tube is exposed to in it's operating environment.

Using Transient Temperatures

Select this option to apply a temperature solution from a transient thermal analysis. Select a transient solution from the drop down list and then use the slider bar under this list to pick a particular time in the solution. The transient solution applies a fixed average temperature per ply to the model This gives a good approximation for the stresses generated by the transient model.

Using Process and Transient Temperatures

Select this option to apply the ΔT from both process and transient temperature inputs. Note that the final operating temperature is where the delta T baseline is defined. If the transient temperature value at a particular ply is higher than the process temperature then a positive Δ is applied and vice versa. Finally a delta T is applied that defines the difference between the transient+process temperature and the final operating temperature.

Using ΔT from the laminate Definition

Select this option if you wish to observe stresses within the tube with the DT values defined within the laminate. You may wish to use this option if looking at stresses from surface heating or heating from fluid flow within a composite tube.