CMH-17 updates composites data, will publish new Volume 7 on additive manufacturing

The Composite Materials Handbook-17 (CMH-17) provides standardized methods and guidance for the characterization, testing and use of composite materials, particularly in aerospace applications. Its six published volumes establish a consistent approach for how to generate, analyze and qualify composite material data.

CMH-17 is not a regulatory standard but seeks to provide a common technical framework for industry, government and certification authorities. It defines procedures for:

• Conducting mechanical and physical property tests on composite materials.
• Developing and documenting statistically based design allowables.
• Accounting for variability, environmental conditions and processing effects.
• Managing data quality assurance and database management for composites

The handbook is maintained by the CMH-17 Coordination Group, a consortium of experts from government agencies, industry and academia. The handbook is an important resource, providing a technical foundation for the qualification and certification of composite materials, enabling consistent, traceable and statistically valid design practices across the aerospace community.

From Mil Handbook-17 to AAM and eVTOLS

CMH-17 started decades ago as Mil Handbook-17, explains Royal Lovingfoss, director of Advanced Materials & Processes at the National Center for Advanced Materials Performance (NCAMP), a program of the National Institute for Aviation Research (NIAR) at Wichita State University (Wichita, Kan., U.S.). “Since then, it has evolved, leaving the military side and taking on FAA sponsorship in 2006, with the CMH-17 Handbook annotation adopted in 2012.”

Starting in 2012, NIAR has operated as the Secretariat, says Lovingfoss, “which means we help to coordinate how the actual CMH-17 Handbook is put forth, as well as coordinate when the virtual and in-person working groups and general meetings occur.”

He notes there are many different working groups operating under the CMH-17 banner, such as Testing, Statistics and Guidelines, as well as the Materials and Process Working Group.

“Our newest, the Additive Manufacturing Working Group, was added in 2018. All of these post information into the handbook, and as the Secretariat, we at NIAR ensure that material is indeed appropriate and meets all of the formatting requirements. We also help coordinate communications between the different working groups.”

“There are also special task groups such as Bonding Process, Sandwich topics and statistics topics like Statistics Process Control. These task groups are temporary and they solve discrete interdisiplinary problems or document specific situations.”

CMH-17 also includes members from different levels of industry, notes Lovingfoss, “from Tier suppliers and smaller sub-tiers, like Fiber Dynamics, up to large OEMs, like Airbus and Boeing, and everyone in between, including materials and equipment suppliers. For example, Toray, Hexcel, Syensqo and Teijin are all large companies that participate, but we also have small mom and pop shops that may have a vested interest in a particular material or aircraft type.” The latter can be in general aviation, spacecraft and/or commercial aviation, which also encompasses eVTOLS, unmanned aerial systems (UAS) and advanced air mobility (AAM). “Several companies producing these newer types of aircraft are becoming more involved in CMH-17, such as Joby and Archer,” he adds. “We also have engine companies that participate, including GE Aerospace, Rolls-Royce and Pratt & Whitney.”

Lovingfoss points out that CMH-17 is worldwide, with members from almost every major country that works with composites and advanced manufactured materials. “A lot of the companies that participate in CMH-17 are based in Europe and Asia, such as Toray and Teijin,” he explains. “But there are many others. So, there’s no issue with foreign organizations working with us or submitting data on just input, whether that’s on materials, processes, damage tolerance, guidelines or CMC [ceramic matrix composites]. We want engagement from all different types of groups in the global industry.”

Volume 7 – Additive Manufacturing

The new Volume 7, set to be released by the end of 2026, will be dedicated to nonmetallic additive manufacturing (AM) materials that can be made publicly available. It will focus on fused filament fabrication (FFF) — also known as fused deposition modeling (FDM) — and laser powder bed fusion processes, which includes selective laser sintering (SLS), but content on other technologies will be added in subsequent releases.

“This volume will enable companies and organizations to design with these materials and understand the type of material and process controls they need to have in place for aviation-grade parts,” says Lovingfoss. “This type of data isn’t out in the industry right now. Many groups have done their own development work, but that data is typically held as proprietary. CMH-17 Volume 7 will offer a single accessible repository, so that you don’t have to piecemeal data from 10 or 20 different reports, which will support wider use of these materials in certified components.”

Materials being reviewed by the Data Review Working Group include filaments made from neat polymer and also with chopped/milled fiber. For example, Stratasys’ (Eden Prairie, Minn., U.S.) Ultem 9085 neat PEI will be included as well as its Antero 800 unreinforced PEKK and 840CN03 microfiber PEKK materials. Hexcel’s (Stamford, Conn., U.S.) HexPEKK-100 reinforced with finely chopped/milled carbon fiber for SLS will also be included. Markforged (Waltham, Mass., U.S.) has also submitted a data set for continuous fiber-reinforced filament.

Volume 7 will also contain a lot of discussion about key topics, says Lovingfoss. “There will be introductory discussions about different AM processes and also about testing and statistical analysis for AM materials, specifically looking at sources of variation. The Guidelines Working Group and Material and Processes Working Group will also add to a more generic baseline of information for people that want to explore using polymer AM in their next aviation product, including information to understand the steps involved in certification.”

Revisions in Volumes 3, 5, 2 and 6

Volume 3 is going into revision H and is available for purchase now from the CMH-17 Publisher, SAE International. This will include significant updates on bond processing, design and analysis, certification steps for bond processes, bolted joint design and analysis, durability and damage tolerance and supportability of bonded and bolt repairs, as well as integrated crashworthiness and some structural engineering technology discussions. It also includes new chapters for spacecraft and engine applications.

Volume 5 revision B, scheduled for release in early 2026, will focus on CMC. Revision B includes the first CMH-17 published CMC data set on oxide fiber-reinforced oxide matrix — also known as Ox/Ox composites or OCMC. This revision will also include fiber material property testing, design considerations, creep testing of CMC and new content based on selected environmental barrier coatings (EBC).

Even though there is quite a bit of carbon/carbon CMC and silicon carbide (SiC) CMC testing going on in the industry, notes Lovingfoss, “most of that is not publicly available. If there is such data that is publicly available, then we would encourage companies to reach out to us.”

Volume 2 revision J, planned for release in summer 2026, will include new datasets and updated definitions. “The gist of this revision is adding more materials to this volume on Polymer Matrix Composite Materials Properties,” says Lovingfoss. “Most of this data is based on prepreg laminates, including woven and unidirectional reinforcements, but these may be produced using hand layup, automated fiber placement [AFP] or press consolidation. There is also some data on thermoplastic composite laminates made from semi-preg, which is also known as organosheet, and is in a sheet form instead of on a roll.”

The last release will be Volume 6 on Structural Sandwich Composites, he continues, “where we are reviewing composites made with core materials. There was some debate about which volume this belongs in, but it was decided that the Sandwich Structures Working Group would review this data at a minimum. The first data sets being vetted are for Nomex honeycomb core, but we will also include data on metal hexagonal honeycomb and corrugated core, as well as foam core to match the information in Volume 6. Data for all of the CMH-17 volumes must meet pedigree requirements to be considered.”

Teresa Vohsen, part of the CMH-17 Secretariat Team at NIAR, adds that for nonmetallic honeycomb, the working group is including hexagonal core (hex core) and also flex core — which has cells shaped to make the honeycomb more easily formed into compound curves. “This revision for Volume 6 will be a large overhaul, with information added about structural design as well, so it will probably double in size,” she notes.

Capturing knowledge, growing composites applications

“There are a lot of exciting things happening in CMH-17 — a lot of growth and change, as well as a fast publication cadence,” says Vohsen. “We've got two books coming out this year, two books next year and at least one in 2027. We’re filling a really important gap in the aerospace industry. A large chunk of engineers are retiring or preparing for retirement, which means there’s a lot of knowledge that is going to be missing when they leave. CMH-17 helps capture that knowledge.”

Vohsen explains that as a young engineer, she used CMH-17 to help ask more educated questions. “This role in industry is important, and as knowledge transfer needs continue to grow, I think people need to understand how CMH-17 is able to help companies and their engineers by giving them the opportunity to know these best practices that took 20-30 years to develop, and also that we’re updating that content and growing into the latest materials that will be used to support the future of aviation.”

Getting involved 

CMH-17 is a growing organization that is free to join. There is an upcoming virtual Coordination Meeting and information can be found on the CMH-17 website. The organization, which includes subject matter experts from certifying agencies, government, academia and industry, works together and collaborates to continue growth of the team-driven handbook content and to foster a thriving network of industry experts.