CW Blog
By: Scott Francis 3. January 2019
CW's top 10 posts of 2018
Thermoplastic tape, here, shown as it is wound onto a spool following prepregging, enjoyed use in composites manufacturing, notably in military aircraft applications, back in the 1970s and 1980s. But a subsequent lull in their application delayed material development, putting them behind thermoset tapes. However, the appeal of thermoplastics, particularly for potential out-of-autoclave aerospace applications, has re-ignited interest and product development.
From CW’s #1 story of 2018, on thermoplastic tape.
Source: Barrday Composite Solutions
Happy New Year!
It’s early January and a time to reflect upon the past year while looking ahead to 2019. As we look back, here’s a list of the most viewed articles on the CompositesWorld website in 2018.
Read MoreBy: Sara Black 1. January 2019
The best job I ever had
Editor’s note: CompositesWorld senior editor Sara Black, the magazine’s longest tenured employee, is retiring at the end of February. I asked Sara, as she says good bye, to reflect on her two decades of working in and writing about the composites industry. Below are Sara’s parting words. She will be missed. — Jeff Sloan, editor-in-chief
Well, I’ve come to the end of the road here at CompositesWorld, and will be officially retired next month — although you might see my byline now and again as a contributing writer. How did nearly 20 years come and go so quickly? I got this job through a newspaper ad in the summer of 1999 and was lucky enough to figure out what “the glue and the string” meant, at least for simple applications. Eventually I was able to cobble words together in the magazine’s style. I had never interviewed anyone before, so that took some courage to do, and to learn. An early lesson: Shut up and listen and use a small pocket tape recorder, then transcribe the tape.
Read MoreBy: Peggy Malnati 31. December 2018
Autocomposites from waste: Garbage in, valuable, functional parts out
This photo shows some members of the Ford Motor Co. research team currently working on new applications involving biopolymers, natural fiber reinforcements, and giving new life to (formerly) waste materials. From left to right, Alper Kiziltas, Ph.D., lead research scientist, holds a fan molded from glass reinforced PCR PP / PA6/6 and he sits next to a seat covered in bio-based PET fabric; Dan Frantz, research engineer, holds a soy-based polyurethane foam block used for seat cushioning; Debbie Mielewski, Ph.D., senior technical leader, holds coffee chaff and a headlamp housing molded with carbonized coffee-chaff-filled PP; Cindy Barrera-Martinez, Ph.D., research engineer, holds a bamboo stalk and a bio-based polyurethane engine cover incorporating recycled tire rubber and she stands behind a cellulose/LFT hybrid composite console substrate; Sandeep Tamrakar, Ph.D., post-doctoral researcher, holds a cellulose/LFT hybrid composite sill shield; and Md. Golam Rasul, doctoral intern, holds a kenaf-reinforced PP door bolster. Source | Ford Motor Co.
Hyundai Motor Group’s composite pillar trim panel is featured in the company’s 2011 MY Kia Pride subcompacts and Optima midsize sedans, plus Hyundai Elantra midsize sedans. The textured parts feature tiny flecks of color and have a fabric-like feel, which enabled the automaker to eliminate the cost of fabric wrapping the parts and the cost and environmental burden of painting them. Source | Hyundai Motor Group
This electrical cowl bracket, featured in Ford Motor Co.’s F-150 pickups, is injection molded from rice hull-reinforced polypropylene. The automaker says rice hulls were a drop-in replacement for talc, reducing development costs and time and eliminating the need for tooling changes. The material is both renewable and recyclable. Source | SPE Automotive Division
Ford Motor Co. has used a number of interesting composite materials on its high-volume F-150 pickups, one of which is an electrical cowl bracket injection molded from rice hull-reinforced polypropylene (PP) that debuted in the 2014 model year vehicles. Yazaki North America, Inc. (Canton, Mich., U.S.) was the system supplier, A. Raymond Tinnerman (Rochester Hills, Mich., U.S.) was the molder, and Rhe Tech, Inc. (Whitmore Lake, Mich., U.S.) supplied the resin for this program. Source | Ford Motor Co.
Agricultural waste is not the only source of beautiful, functional automotive parts. Hyundai Motor Group developed an interesting composite comprising the volcanic rock scoria, polyethylene terephthalate (PET) fabric pile, glass microspheres, and PP resin to injection mold pillar trim panels. Source | SPE Automotive Division
Another interesting use of “waste” materials was a circular recycling program that produced air baffles for the 2011 MY Chevrolet Volt hybrid electric vehicles from General Motors. The parts were injection molded from equal parts styrene butadiene (SBR) rubber, PP and polyethylene (PE). The material was obtained from shredded automotive tires, plastic packaging aids from GM’s production facilities, post-consumer bottles, and oil-containment booms that had helped clean up the Gulf of Mexico after the Deep-Water Horizon spill in 2010. Interestingly, the booms themselves had been produced from recycled automotive plastics waste, bringing the materials back full circle. Companies involved included system supplier GDC Inc. (Goshen, Ind., U.S.) and boom material supplier Mobile Fluid Recovery, Inc. (Seguin, Texas, U.S.). Source | SPE Automotive Division
The 2011 MY Chevrolet Volt hybrid electric vehicle from General Motors features a recycled composite air baffle.
A comparison of % strain (left) and stress (right) vs. energy dissipation/unit volume for fiberglass, hemp fiber, and cellulose fiber for a vinyl ester matrix shows that natural fibers dissipate energy at lower stress states and higher strains than glass, which, in turn, demonstrates that natural fibers offer improved energy absorption at higher strain rates. Source | Ford Motor Co.
In a lot of industries, the aphorism “garbage in, garbage out” is a reliable maxim. If your inputs are of poor quality or little value, your final products will probably be as well. However, the automotive industry is turning that adage on its head by repurposing waste materials normally considered to have no use into functional, beautiful and valuable automotive parts for vehicles already on the road. In doing so, automotive companies are keeping materials out of landfills and waterways, providing jobs in distressed communities and giving farmers another income stream, all while reducing part weight and cost, stabilizing long-term material prices, and greening their vehicles. This is a good example of another saying: “One man’s trash is another man’s treasure.”
A lot of these repurposed waste materials are the agricultural by-products of food production. They’re generally the outer wrappings of crop plants, such as tomato skins from ketchup production or agave fiber from tequila production. These inedible wrappings (often from seeds) are the parts of plants that either will not compost or will not compost easily, and that have little or no utility as animal bedding. Their lack of utility causes these wrappings to accumulate in waste piles where they can prove a nuisance or, if ignored long enough, become a health and safety challenge. However, these fibrous outer wrappings are proving to be useful as natural fiber reinforcements for a variety of composites.
Read MoreBy: Jeff Sloan 28. December 2018
Developing next-generation composites talent
M.C. Gill Composites Center
The University of Southern California’s M.C. Gill Composites Center, within the Viterbi School of Engineering, is endowed by a donation from namesake M.C. Gill, a USC alumnus and founder of composites fabricator Gill Corp. Photo | CW
Fig. 1 A Dedicated Educator
Steve Nutt (center) is director of the University of Southern California’s M.C. Gill Composites Center and, for 24 years, has been a professor of engineering at USC. Photo | USC
Fig. 2 Composites Center laboratories
The M.C. Gill Composites Center is spread out among several lab spaces at USC and offers students access to a variety of equipment, machinery, materials and technology. Photo | CW
Fig. 3 Miniature autoclave for student research
This schematic shows a cutaway view of the miniature autoclave, with viewport, that M.C. Gill Composites Center students use to conduct in-situ visualizations of resin, fiber and core behavior during cure. This is autoclave Mark Akers used to conduct his research on air bubble behavior. Image | Mark Akers
Fig. 4 Core-and-laminate research sample
This shows the open autoclave, with viewport visible. A USC student is holding sample of the type of core-and-laminate construction used with the autoclave. The sample was placed core-side down over the viewport, bagged, sealed and cured. Photo | CW
Fig. 5 Autoclave viewport
Looking at the miniature autoclave from below, one can see the viewport and video recording equipment used by students to study material behavior during the cure process. Photo | CW
Fig. 6 Research results
This micrograph of the cured core-and-laminate sample shows bubble formation in the four cases evaluated by Anders. The top two rows, Cases A and B, show significant bubble formation, as well as intermingling of the resin and adhesive. The bottom two rows, Cases C and D, show significantly reduced bubble formation and good segregation of resin and adhesive. Photo | Mark Akers
Fig. 7 Prepreg dewetting
Sarah Schechter’s work at USC has focused on development and evaluation of prepreg dewetting processes, and their affect on cured part properties. Dewetted (or discontinuous) prepreg should, in theory, allow air to escape the laminate and core in the z-direction during cure. These micrographs show resin condition after dewetting at two intervals, 30 seconds and 2 minutes. Photo | Sarah Schechter
Fig. 8 Better air evacuation
This illustration exemplifies the air evacuation advantage conveyed by relatively large openings (right) in dewetted prepreg. Traditional continuous prepreg, by comparison, only allows in-plane evacuation. Photo | Sarah Schechter
Fig. 9 Internal and surface porosity
These micrographs show internal and surface porosity for the three prepreg types Schechter evaluated. Data from her work showed that prepreg dewetted at 104°C for 2 minutes (104-120) produced cured composite parts with the best properties. Photo | Sarah Schechter
Any educational institution that has developed a specialized area of study — engineering, history, art, medicine — likely can trace its genesis back to a person who supplied a great deal of personal dedication and passion to help bring that specialization to life. More often than not, that person is an educator, and someone who sustained that dedication over many years, in the process drawing the students and acolytes who built the critical mass necessary to make the program self-sustaining.
The composites industry, which is itself relatively young, has had only a little time to develop such specialization at colleges and universities. Still, throughout the world, there is now a healthy handful of strong composites engineering programs that are turning students into composites manufacturing professionals.
Read MoreBy: Ginger Gardiner 27. December 2018
Composite radar masts assembled for megayachts
Large composites, creative transport
This 10 x 14m carbon fiber composite canopy requires a creative solution for transport to an assembly site where it will be joined with a 10-m-tall radar mast and installed on the 90-m-long yacht for which it has been designed. Source for all images | Vabo Composites
Fig. 1
The 10 x 10 x 10m glass fiber/vinylester mast for a 156-m-long yacht features two legs joined to form a “T” from which four platforms extend, three forward and one rearward.
Fig. 2
This carbon fiber/epoxy radar mast and canopy cut weight 50% vs. aluminum for a 90-m-long yacht, lowering its center of gravity and improving its stability.
Step 1
Vabo Composites CNC machined 10 molds for the glass fiber/vinyl ester mast project (shown here) and seven molds for the carbon fiber/epoxy project comprising mast and canopy.
Step 2
Parts fabrication began with laying glass reinforcements onto molds, along with perforated foam core, to create a dry laminate stack.
Step 3
Dry stacks were vacuum bagged and Vabo Composites’ one-shot resin infusion method was employed for the glass fiber/vinyl ester mast, with legs and platforms completed in 2-3 hours.
Source | Klaas Eisens AV, Vabo Composites
Step 4
Infused glass fiber/vinyl ester parts were demolded.
Step 5
Reinforcing ribs were CNC machined — including holes for cables and exhaust pipes — from resin infused foam-cored glass fiber/vinyl ester flat panels.
Step 6
Ribs were bonded to the mast legs at roughly 1m intervals.
Step 7
The two large legs, four platforms and all other parts were trucked to a covered shed adjacent to the yacht construction yard for assembly and installation.
Source | Klaas Eissens AV, Vabo Composites
Step 8
The composite legs were prepared for final assembly, inserting exhaust pipes and cable chases.
Source | Klaas Eissens AV, Vabo Composites
Step 9
Each leg was lifted by crane onto a rail-mounted fixture and slid into scaffolding that located and supported legs and platforms during assembly.
Source | Klaas Eissens AV, Vabo Composites
Step 10
A single-piece mast is crane-lifted and prefit to the yacht, followed by final systems installation, exterior painting and, at last, final installation onto the yacht.
Fig. 3
Vabo Composites’ second mast project will install this carbon fiber/epoxy radar mast on top of the canopy to form a single-piece, installation-ready assembly for a 90-m-long yacht.
Vabo Composites (Emmeloord, The Netherlands) designs and builds a diverse array of composite structures. The company began in 2001 with several small marine projects, as well as antennas for mobile television broadcast systems, carbon fiber-reinforced manipulator doors and valves for fast-moving palletizing machines and a glass fiber-reinforced front-loader bucket, for which it won a 2015 JEC Innovation Award. The company has also become adept at architectural and building projects and continues to advance its industrial production of ACCEDOO composite ship doors (read “VABO Composites: Dutch innovator excels in diverse applications”) which won a 2017 JEC Innovation Award.
Vabo Composites has also become well known for its expertise as a fabricator of large radar masts for yachts, which house navigation electronics and circuitry as well as exhaust systems from the engines. It has recently completed a 10-by-10-by-10m glass fiber/vinyl ester mast for a 156m-long megayacht, as well as a 10m-tall mast with a 10-by-14m canopy beneath, both made from carbon fiber/epoxy, for a 90m yacht. Normally built from aluminum, these composite masts provide unparalleled structural performance, resist corrosion, help lower the center of gravity on the yacht and, of course, save weight — the first mast, made using glass fiber, achieved a 30% mass reduction and the second, made with carbon fiber, increased mass savings to 50%. “The average weight for this lighter carbon composite structure is 10 kg/m2 while the canopy is supported at only four points,” says Vabo Composites director Arnold Vaandrager. “Aluminum was not an option because of the lightweight and structural performance required.”
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