A general tubeform can be built with various shapes between the ID and OD. The k sliders will change the shape between the diameters. These can be used to vary axial stiffness, shrinkage, balancing shear strains, and other.
Tubeform shapes are generally used for their "soft" axial stiffness, typically for vibration and shock isolation. The isolation can consist of the vibrating suspended object (reciprocating engine for example) being isolated from the "ground" (frame the engine is mounted to) or vibration/shock from the "ground" isolated to the suspended object. In some cases, they serve both purposes. The inner member bonded to the ID of the shape supports the weight of the suspended object and the outer member bonded to the OD is attached to "ground".
The dimensional unit choices are shown. The solution is done in SI units (N, m and K) but converted back for the results in the user preferred system. Typical values are defaulted but can be changed by the user.
The state of cure can be determined at various times. The solution stops when 100% of the volume has reached 90% cure. The link explains the method used. The cure parameters are defaulted to typical SI values for black rubber. The user can change them and should to understand their influence on the results.
The curing shrinkage can be determined with the resulting shear strains. Shrinkage is determined by the difference in molding temperature and room temperature and the material thermal coefficient of expansion. It is assumed the ID and OD surfaces are fully bonded to inner and outer metals at cure and do not deflect.
An axal stiffness is calculated using a 20% vertical deflection based on the average of the ID and OD thicknesses. The combined axial load and shrinkage shear strains are determined and shown.
The static and estimated dynamic stiffness values are determined from the user input material tan δ.
