A new book on double-double

Learn more on double-double !

Double-double – a new perspective in manufacture and design of composites

and the 2nd edition :

Simplifying the Design and Manufacture of Composite Laminates

Double-double (DD) is a new class of composite laminates, replacing the conventional quad that limits ply angles to 0, ±45, 90, and many other laminates called unconventional. In contrast, DD consists of two pairs of ply angles:


The goal is to have laminates that will be easier and faster to produce with lower weight , higher strength and so lower cost. Many manufacturing innovations can be achieved with DD and are not otherwise possible with the conventional quad laminates and unconventional laminates.
The first achievement was the use of one parameter for stiffness in trace, one parameter for failure criterion by leveraging Nettles circle, individual ply drops instead of symmetric pairs, one-axis layup with no cross-plying, and one continuous layup without stopping for mid-plane symmetry. The next step now introduced in the book is : one test for interlaminar stress, one laminate for design allowable generation, and one of two stacking sequences for DD to reach homogenization the fastest, and more simplifications to come.

All these steps that will make composites easier and lower cost to produce are enabled because of the homogenization of DD laminates. They are like orthotropic metals, but better than real metals because DD can have directional properties; DD can be tapered to save weight with which neither conventional and unconventional laminates, nor metals, can compete.

Download the free e-book in the “e-books on DD download” menu of this website or on Stanford website starting. By downloading a book or a software, you will become automatically member of Think Composites org. and you will be entitled to special offers and discounts on books, webinar, etc… from us.

THINK COMPOSITES is a nonprofit organization founded in 1983 by Professor Stephen W. Tsai and Dr Thierry Massard

Our mission is to promote the use of composite materials in the industry and the education in the field of of composite materials in Universities, Engineering Schools and Professional Schools.

We encourage actions aiming at supporting research, innovation in the field of composites  and their contribution to a better world.

Think Composites acts as a network of highly competent scientists. For almost 40 years the Think Composite Global Team has been active in many domains from theoretical approaches to manufacturing and characterization in order to offer new roads to composite materials stronger, affordable and durable.

We offer services to industry in the form of consulting, specific design tools, training course, seminars, continuing education, MOOC, etc.

Our resources come from membership fees, donations, consulting sessions, short training courses and continuing education programs.

We welcome all volunteer collaborations in the field of our work on composites design. Researchers, engineers, technicians, students can collaborate with us and find profitable outcomes for their own work.

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