Software Review: The LaminatorDateline: 08/04/99
The Laminator is a small program for performing simple laminated plate calculations. I first reviewed The Laminator about two years ago, when it was at version 2.03. At that time, it featured a simple, easy-to-use interface, and was an excellent choice for performing quick point-stress analyses.
The current incarnation of The Laminator, version 2.50, makes some minor improvements upon the interface, but otherwise provides the same functionality as the previous version.
Installation is still incredibly easy: just unzip the archive file and you're ready to go. The program consists of one executable file and, new in this version, a help file. There are no registry entries (so you can easily move the executable to a new location) and no INI files. You have to create your own icon, but that's a good trade for simple installation.
As before, you enter material properties (engineering constants and strengths), stacking sequence, and loads; the program calculates laminate properties, constitutive matrices, stresses and strains, and failure indices.
The data entry forms are essentially unchanged, but the main program window sports a new look. Rather than clicking buttons to enter data, the different forms are available through a tabbed dialog interface. This makes it a bit easier to navigate among the forms.
(Click on the links above or the pictures below to see the full-size screen images.)
Original Interface of The Laminator
New Laminator Interface Showing Loads Form
Input can be either interactive or from a file. The file format is a simple text file containing material properties, the stacking sequence, and the load vector. The format hasn't changed since the previous version, so old files can still be used. Once an input file is read in, all input values can be modified or added to interactively. The input data can be saved using a standard File menu command, as opposed to the old method of selecting a calculation option.
The data entry tables look pretty much as they did in the old version, but a few shortcuts have been added. Now you can insert, delete, copy, or paste rows, as well as copy and paste cell values.
Original Stacking Sequence Entry Form
There is no master database for material properties: rather, they are stored in the input file with the laminate definition and load vector. The number of allowable materials per file has been increased from five to ten.
The load vector can consist of any combination of mechanical loads (force and moment resultants, or strains and curvatures), thermal loads (uniform temperature change), and moisture loads (uniform percent moisture content). My only complaint here is that switching between forces and strains loses any entries you've made. It would be nice if the program remembered your entries, so if you later change your mind and switch back to the original loads your entries would be restored.
Results are output in a simple plain text format which is displayed on the screen and can optionally be stored in a file. The results can also be printed from the display screen. To redisplay the results page from within the program, you must rerun the solution, but solution speed is fast (less than one second for the sample 8 ply laminate). The results can include all matrices; for unsymmetric laminates, the engineering constants include shear coupling coefficients.
I only found two minor bugs in the program. The first is a printing bug has crept back in from the previous version. It causes the program to crash if you click the print button and then cancel before sending the file to the printer. The author fixed this bug quickly after I pointed it out in my first review; I expect a revision will be posted very soon.
The second occurs in the Loads view when resizing the form. The entry boxes for thermal and moisture loads don't move if the width is shrunk, so they can disappear from the window. However, they comfortably fit in the default width, which is a bit over 400 pixels, so this shouldn't be a problem even at low resolutions.
The Laminator remains a good choice for quick plate analyses. If you registered the previous version, the upgrade is free (as are all future upgrades). Download the fully functional program and give it a try.
Program DetailsThe Laminator
Written by Mike Lindell
Classical Laminated Plate Theory analysis of composites
Mechanical, thermal, and hygral loads
About the Author
Mike Lindell graduated from the University of Delaware in 1981 with a Bachelors degree in Mechanical Engineering. He earned a Masters degree in Engineering Science and Mechanics while working for NASA. Mr. Lindell currently works for NASA at the Langley Research Center in Hampton, VA. His work involves finite element analysis of space and aircraft structures and experiments.Previous Features