Concyl Overview
Concyl is a structural analysis tool that computes the stresses, strains, and displacements within a
system of perfectly bonded concentric cylinders under the combined effects of thermal, pressure,
and axial loading. Each cylinder in this system can have a unique set of isotropic elastic material
properties including a unique stress-free temperature. This results in a statically indeterminate
generalized plane strain problem in one dimension. All of the solution quantities vary only in the
radial direction. Real-world examples of such systems include multi-layer pipes and pressure
vessels▼, shrink-fit multi-cylinder shafts▼, and cylindrical solid rocket motors▼. The input to Concyl consists of the initial inner and outer radii for each cylinder, the material
properties for each cylinder, and the applied loads. The applied loads can include internal
pressure, external pressure, a uniform thermal load for each cylinder, and a uniform axial strain
applied to all the cylinders. Complex arbitrary thermal gradients through thick pipes can be
approximated using a collection of cylinders, each with a unique stress-free temperature. The
unique stress free temperature for each cylinder can be used along with a suitable applied thermal
load to simulate the pre-assembled radial interference for shrink-fit or press-fit problems. The
output from Concyl includes the stresses, strains, displacements, and strain energies at the
interfaces between all of the cylinders. These solution quantities can also be computed at any
number of equally spaced radial locations within each cylinder.
Concyl incorporates a high-speed solver that computes the exact solution to the governing
equilibrium, kinematic, and constitutive equations. This can have considerable speed and
accuracy advantages over approximate methods such as the finite element method. Another
advantage of Concyl is that, unlike most finite element programs, Concyl is well-behaved for
incompressible materials (Poisson ratio equal to 0.5).
Concyl has many useful features including the capability to read input files and write output files.
Concyl can read all the required input data from a specially formatted file▼. Concyl can also write
all of the input and solution quantities to a formatted output file▼. Concyl can also generate a tab-
delimited database file that can be used to make plots of any solution quantity as a function of
radius. Although Concyl has no built-in graphics capabilities, it can generate plots using Microsoft
Excel via the Excel COM interface▼. Concyl includes a Windows graphical user interface▼ (GUI) to facilitate entry of all of the required
input and also display all of the computed results.
The GUI includes advanced error checking
features as well as input file drag and drop capability.
Alternatively, Concyl can also be run in a non-
GUI mode with various command line options▼. The non-GUI mode is most useful for doing
large batches of Concyl runs using scripting languages such as Perl. This version of Concyl is
limited to 99 cylinders.
Freeware Notice
This version of Concyl is freeware and was
developed for demonstration purposes only. While considerable effort
has been made to verify the accuracy of the program, the developer does not
warrant or assume any legal liability or responsibility for the accuracy,
completeness, or usefulness of the program for any particular purpose.
Copyright Notice
This program and documentation, including
the Concyl name, were created by and are owned by Toby Norris. This documentation may not
be copied, reproduced, transmitted, distributed, or otherwise used in whole
or in part (individually and collectively "Reproduced") in any manner
without prior written consent, except to the extent that such use
constitutes "fair use" under the Copyright Act of 1976 (17 U.S.C. ยง 107).
Email address:
concyl@tobynorris.com