JEC COMPOSITES MAGAZINE - Issue #71 - March 2012 - 104

design tools

Free design tools with unmatched easy, speed and sophistication
Two new powerful composites analysis and design tools are now available for researchers and designers that can produce fast answers.
components in tensile, compressive, and shear directions, but also thermal expansion coefficients, many micromechanical parameters and their temperature dependency, and ply degradation factors for ultimate strength prediction. The detail description of these parameters can be found in an e-book, “Theory of Composites Design,” available for US$4.99 at http://compositesdesign. stanford.edu. The outputs for i-MicMac are 1) Effective stiffness, thermal and moisture expansions of the laminate. 2) Strength ratios (safety factors) of

By
Stephen W Tsai, Professor Research Emeritus, Department of Aeronautics & Astronautics, Stanford University Sangwook Sihn, Senior Research Engineer, Multi-Scale Composites and Polymer Division, University of Dayton Research Institute, Dayton, OH, USA.

ack in 1984 when Macintosh was first introduced, only available software packages were Write, Draw and Multiplan. We were forced to learn to perform laminate analysis on Multiplan. Through the years, it became Excel, and our laminate analysis became a suite of MicMac (for micro-macromehanics tools for laminate analysis). Now with iPad, we are offering a composites app, called i-MicMac. This personal productivity tool is free to all interested users of iPad and downloadable from Apple’s App store. In our semi-annual online intensive workshops to pioneer creatively designed composites, we recognized that the point-stress analysis of MicMac was only the first step. Composites design needed finite element analysis. By leveraging the open capabilities of Abaqus® FEA from the SIMULIA brand of Dassault Systèmes, MicMac-FEA was born by

merging the easy user interface of MicMac with the sophisticated power of a modern finite element analysis solution. We use the stand-alone Abaqus Student Edition to solve many problems including laminate with holes. This MicMac is also being offered free to interested laptop users, not available on iPad. Both MicMac/FEA and i-MicMac share the similar userfriendly input interfaces and selections as follows: 1) Selection of a ply material from pre-existing or userdefined material database. 2) Up to four ply angles, and number of plies. 3) Rigid-body rotation of the laminate. Fig. 1:User interface of i-MicMac running on iPad. 4) Repeat index r to build thick laminates; i.e., r ≥ 1. 5) Operating temperature and moisture content for residual stress calculation. 6) Imposed stress resultants: {N1, N2, N6}. Material properties include not only basic (macro-level) uniaxial stiffness Fig. 2: Ply data format and strength

104 jec composites magazine / No71 March 2012

http://compositesdesign.stanford.edu http://compositesdesign.stanford.edu

JEC COMPOSITES MAGAZINE - Issue #71 - March 2012

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #71 - March 2012