Mechanics of Composite Materials

EML4230                                                                                                     EML6232

Magazine Articles on Composite Materials




Mechanical Engineering, Vol.126, No. 1, January 2004

This article describes the development of a fiberglass-reinforced window by a university professor that claims it is more resistant to high winds than today's hurricane-resistant glass.

The difference between the new window and the standard versions is the nature of the reinforcement. Standard hurricane-resistant windows have inner sheet of polyvinyl buteryl, a thermoplastic and the professor's idea is to replace the inner plastic layer with one of clear thermoset polyester, reinforced with glass fibers, making the windows stronger and lighter.

Potential applications for the new glass include coastal areas, aircraft windows and commercial buildings.

Summary by V. Ristevski, Fall 2004


SOUND EFFECTS, Your tee shots may not be longer, but they sure are louder
Golf Magazine, PP. 86-87, December 2001.

 This article highlights the new phenomenon of golf club manufacturers building clubs that sound as or more powerful than they perform.  This shift is rooted deeply in the fact that one's perception of a good stroke is related to the sound the club makes while hitting the ball.  To satisfy the consumers, manufacturers are utilizing composite materials and material science to engineer an "appropriately aggressive sound".  The focus for development of these clubs rests heavily with the use of composite materials because of their capacity for fine tuning and revision to produce the best sound for the intended purpose.

Summary by S. Johnson, Fall 2004.



Aviation Week and Space Technology, PP. 66-67, April 5, 2004

This article describes a Stork Aerospace product called Glare and its application on the new Airbus A380.  Glare is an Aluminum glass composite that results in 25% lighter Aluminum with better fatigue resistance and higher impact strength.  The article goes on to describe Stork's lay-up process as well as the historical background for the technology.  Airbus will use the composite material to prevent failure due to crack propagation in future aircraft.  Currently the A380 is to use Glare for the hull of the aircraft while efforts are underway to use Glare on the leading edges of that aircraft.

Summary by M. Fieldson, Fall 2004



Advanced Materials & Processes, PP. 81-82, August 2004

The purpose of this article is to compare the microstructural and mechanical properties of copper- and silver-particle reinforced composite with nickel-particle reinforced composite in the application of solder joints.  These reinforcing agents are mechanically added as particulate to the traditional eutectic Sn-3.5Ag solder to enhance important mechanical properties, such as wettablity and creep resistance.  Nickel is selected as a reinforcing agent due to its good wetting characteristics with tin, and its ability to form intermetallics with tin.  The article provides data indicating the creep rate for each type of composite and non-composite solder.  The article also gives advantages and disadvantages of the different composite solders based on their microstructural properties.  This article demonstrates the usage of a different type of reinforcing geometry, particulate, and illustrates how a reinforcing material is selected based on its properties and the properties most desired in the application.

Summary by M. Brown, Fall 2004.



Popular Science, August 2004

This article found in Popular Science magazine introduces the latest technology in nanocomposites, Metal Rubber.  Despite containing just parts per million of metal, its ability to be twisted, stretched, fried and still conduct electricity as well as solid metal makes it unique to the world of material science.  Since Metal Rubber is a product of nanotechnology it must be fabricated molecule by molecule through the process of electrostatic self-assembly, which is described in the article.  Metal Rubber projected applications may vary from artificial muscles and shape-fitting wings to abuse-resistant flexible circuits.

Summary by S. Alverio, Fall 2004



Mechanical Engineer, PP. 40-42, July 2004 

The article focuses on finding uses for small diameter trees often discarded or left behind by loggers.  The mechanical engineer's job is to analyze solid wood and pressed-wood fiber composites to develop new materials like laminated wood I-beams and fiberboard.  The analysis focuses on microwave heat transfer for uniform drying when using conventional heating and straightening.  The other portion of the analysis focuses on finding a fiberboard from the chopped off discarded pieces of lumber that has the best strength and physical properties.  The researcher reported that they "developed materials from the fiberized treetops that have a 30 percent greater tensile modulus and a 50 percent increase in tensile strength over industrial hardboard standards."

 Summary by C. Papangelou, Fall 2004



 Innovation Could Extend Life of Everyday Items

 February 15, 2001, by Guy Gugliotta, Staff writer, of the Washington Post.

Researchers have developed a process that enables a continuous regeneration and repair of polymer matrix composites by activating specified resin filled capsules stored within the material.


Composite life is determined by fatigue. Composite structures in commercial application, such as aerospace and automotive industries, are subject to dampening or vibration.  As time passes, damage occurs as cracks radiate through the polymer and weakens the composite to the point it needs repair. Due to the complication of mechanical characterization, conventional approaches for repair are tedious, time consuming and non-cost efficient.  


The standard repair techniques include drilling, plugging, patching and sanding. The process has expanded to include injecting resin into holes drilled into damaged areas. Modeling his method after how the human body repairs itself, Scott R. White, a materials and aerospace engineer at the University of Illinois at Champaign-Urbana and his team developed an innovative procedure to distribute new resin throughout a matrix and activate it to only in areas where cracks occurred.


White and his team developed microcapsules by encasing microscopic drops of monomer and mixed the capsules into the original resin matrix. A catalyst is blended in and the resulting mixture was molded and set as a polymer composite. The specimen was scored by tapping a razor blade into a groove; the resulting cracks encountered the capsules, pierced them and released the liquid monomer. Polymerization occurred as the monomer interacted with the catalyst, resulting in a resin filler that harden on site.


White's process has commercial applications ranging from increasing the life of a composite to creating products that are more durable. Furthermore, his efforts have implied possibilities in the development of new types of plastics, metals and other materials that have been updated using the latest technologies, to have desirable properties. 

German Vicente


Our Driving Conundrum

Popular Science Magazine, PP 62-66, September 2004

Fifty years from now the hydrogen fuel technology will power our world, from artificial organs to cruise ship and automobiles. The problem of hydrogen fuel technology is very costly to improve energy security, emissions and performance. Average engine horsepower has bulked up by 84 percent since 1981, while average vehicle weight in the U.S. has risen by more than 20 percent in two decades. Polymer-composite materials, particularly those reinforced with carbon fiber, will emerge from niche manufacturing to be used widely as structural material for automobiles. Carbon composite body construction could reduce vehicle weight by 40 to 65 percent. The most technological challenges from carbon-fiber composites are slow, costly, labor-intensive process of laying up carbon-fiber composites and curing them piece-by-piece in autoclaves. Mercedes-Benz SLR uses the carbon fiber blanks and layers them in the large molds, and resins was injected at high speed. The concept calls Fiberforge, which invented by Amory B. Lovins in a computer-modeled concept for ultra light vehicles. Other company such as Lotus Engineering from UK has developed Aero-Stable Carbon Car. While the Borealis Company has patented "thermionic automobile" which used waferlike devices based on something called quantum mechanical tunneling to convert heat to electricity. The composite materials will play a very important role of the vehicles in the next decade.

Summary by Chandra Khoe,  Fall 2004.


Automotive Materials

Advance Materials and Processes, PP. 58-65, June 2004

ASM international publishes a magazine called ‘Advance Materials and Processes'. The magazine regularly publishes articles on automotive materials. It is amazing to see how the composite materials are replacing the conventional materials in automobile industry.

A sand-cast aluminum part that covers the transmission shifting mechanism on Polaris 700 sportsman ATV and Polaris Ranger has been replaced by a glass fiber reinforced polymide. The 2004 Chrysler Town and Country, Dodge Caravan and Grand Caravan uses thermoplastic valve covers made of specially formulated grade of glass/ mineral reinforced Minlon (made by DuPont). The valve cover reduces weight by more than 65% and cuts costs significantly compared to metals. A thermoformable composite of a polypropylene resin matrix and chopped-fiber reinforcement called Azdel Superlite is used to replace the steel in the hood of high powered sports vehicles. In racing cars, aluminum carburetor tubes are being replaced by glass reinforced Amodel polyphthalamide, which combines a high heat deflection temperature with high flexural modulus and high tensile strength.

These are some of the few areas in automobile industry in which composite materials are finding more and more applications. With this pace, we are not far away from our first all-composite automobile.

Summary by Shantanu Shevade, Fall 2004



Aviation Week and Space Technology, PP. 54-55, July 28, 1997

This article is a brief review of the progress made in developing a carbon fiber, all composite, twin engine jet by Williams International. These new powerplants currently have a 3800 lb. takeoff weight with a fuel range of 1600 nautical miles, average speed 270kts. They are being developed to replace the piston-powered light aircraft with reliable, low cost and improved performance all composite turbofan engines. The initial rating of these engines is currently 700 lb. thrust with the potential of 1000 lb. Future developments may include the adaptation of the composite powerplant to replace the turboprop engines in small helicopters as well.
Summary by P. Bond, Spring 1998.



The American Ceramic Society Bulletin, PP. 61-67, December 1997

This article focuses on the advantages and disadvantages of finding the "perfect" reinforcement for discontinuously reinforced metal-matrix composites (DR-MMC). Ideal solutions include creating new casting techniques or develop new "superior" ceramic reinforcements. The problems found with replacing old reinforcements with new has been a give and take situation. Standard reinforcements that have good wetting and disperse well in the matrix have a tendency to be unstable or degrade the composite. New manufacturing methods are needed to overcome these problems. The other solution is to find new casting techniques that will introduce large amounts of particles to the matrix melt. The problems found that need to be overcome is controlling the chemical interfacial reaction . Once achieved, higher levels of particles in the matrix can be obtained with lower degradation of properties. The primary reason for trying to solve these reinforcement and method of manufacturing problems is cost savings. If a method for production can be found, a profitable material would result that can yield an improved performance composite at a reasonable price.
Summary by P. Bond, Spring 1998.



Popular Science, November 1997

Dan McCosh wrote this article that appeared in the November, 1997 issue of Popular Science Magazine. The article tells the story of one Charles Billiu, and his path towards building a car made of composite materials. The article chronicles Mr. Billiu's interest in composite design, as well as some of the advantages and disadvantages of designing an automobile using complex molded composite parts. Although the title touts the plastic car as "A manufacturing marvel that's lighter and cheaper than steel cars," due mention is given to the difficulties scaling composite manufacture into the automotive realm. The article does include pictures of the first prototype of Mr. Billiu's Fun Car Company, and a description of the methods used to create this prototype. The prototype is assembled from eight major molded sections which are bonded together, and fitted with Geo Metro components.
Summary by H. Swain, Spring 1998.



Popular Science, November 1997

This article appeared in the November, 1997 issue of Popular Science Magazine. The article describes the use of polymer-resin composite embedded with microscopic chips of silica to replace traditional bridgework. The material is cured by exposure to bright blue light, which allows a replacement tooth to be easily formed while the material is in its uncured, putty-like state. Resin is used to anchor the formed tooth to its neighbors once they have been chemically etched, and then the entire replacement can be light-cured in place. The procedure is said to take place in less than two hours, and be completely painless.
Summary by H. Swain, Spring 1998.



New Scientist, PP. 36-39, February 1, 1997

This article introduces the possibilities of replacing glass fibers in polymer matrix composites with natural fibers. The natural fibers are renewable, cheap, abundant, recyclable, and safe to handle. Glass is not recyclable and if the fibers are inhaled they can lodge in the lungs just like asbestos. Natural fibers do provide a challenge over glass in three particular aspects: they are less dense than glass, they have a lot of variability in properties from one plant to the other, and it is difficult to control fiber length. The other challenge is to find a matrix that is as recyclable as the fiber. Daimler-Benz is showing support for natural fibers by making the door panels in the Mercedes G-class from plastics reinforced with flax fibers.
Summary by C.D. Hughes, Spring 1998.



Engineering News Record, PP. 34-38, September 15, 1997

Composites are being applied in many structural applications. Some of the advantages of using composites in structures are the lack of heavy equipment required due to the low weight, quicker assembly time, fewer parts required, high corrosion resistance, and similar strength to steel for the stresses encountered. In mid-1998 the largest composite bridge yet is scheduled to be built in Delaware. It will be 164 ft. long and 54 ft. wide. The use of composites is still being questioned due to the high material cost and the lack of history into the durability of composites. The risk of using a material without specified mechanical and physical properties is deemed too great for some companies. However, experts agree that given time the costs of composites will go down and the interest will go up, such that it will be as commonplace as steel and concrete.
Summary by C. D. Hughes, Spring 1998.



The Construction Specifier, Advancement of Construction Technology, PP. 102-106, May 1996

The use of composites is making a huge leap from the traditional aerospace industry into various applications in the field of civil engineering. The use of pultruded sections containing a high volume of fiber produces structural elements similar to those currently used in civil engineering applications. However, to gain the support of the many regulatory agencies involved in civil engineering work, durability aspects of these systems must be known. Several groups are involved in current work through pedestrian bridges and even a bridge capable of sustaining vehicle loads have been constructed are are being monitored to assess the usefulness of composite construction of bridges. Also, composite components of typical high maintenance areas, such as end diaphragms are being created, to see if composites can help control corrosion induced by deicing salt run-off in extremely cold climates. If these projects prove to be successful, the future of composites in civil engineering applications looks promising.
Summary by C. Toth, Spring 1998.



Mechanical Engineering, PP. 59-63, December 1996

The quest for a practical composite car body which meets both cost and structural integrity requirements came closer to becoming reality after a test by the Big Three American automakers, Chrysler, Ford, and General Motors, proved that a composite front end on a Ford Escort could pass a 35 mile per hour impact test. The coalition of automakers is now focusing its efforts on the feasibility of mass producing composite car parts. By assembling certain "focal groups" to assess various parameters of the production method, the Automotive Composites Consortium (ACC) hopes to make composite car parts as cheap or cheaper than the traditional steel parts used today. By lowering the cycle time, minimizing waste, and advancing molding technology the ACC believes that composites are a viable material for use in the future. The paper also gives good insight into future manufacturing processes that will yield better, more consistant parts.Even if the amount of money invested in the project is high, the results of the findings should prove beneficial to all of industry, as composite technology continues to gain widespread acceptance and use.
Summary by C. Toth, Spring 1998.



Popular Mechanics, PP. 74-77, December 1997

About half of 600,000 U.S. steel-concrete bridges need repair. Fiberglass composite bridges could extend its life four times over the previous material. The material costs roughly more than five times, though, they are five times lighter, faster to build, and possibly self-maintained, which means more economical overall. Sun ray, however, might reduce their strength.
Summary by I.S. Lam, Spring 1998.



Advanced Materials and Processes, PP. 49-50, June 1997

This brief article in the magazine's "Tech Spotlight" section explains how composite materials can benefit the sporting goods industry and consumer. It explains the recent reduction in cost that allows composites to be a viable alternative in manufacturing of consumer products such as golf clubs and hockey sticks. The article also gives specific examples of the benefits of of composites, citing lower weight and higher strength in several pieces of sporting equipment. There is also a useful comparison of thermosets vs thermoplastics.
Summary by N.V. Carter, Spring 1998.



Advanced Materials and Processes, PP. 47-48, Feb. 1997

This article, also a "Tech Spotlight", explains the use of sheet-molding composite (SMC) in the automobile industry. It includes a good explanation of the process used to create parts from sheet-molded composite, then goes on to compare the attributes of SMC components to their metal alternatives. There is also a nice explanation of the recyclability of SMC parts.
Summary by N.V. Carter, Spring 1998.



New Scientist, PP. 37-40, March 8, 1997

This article is a detailed, thorough explanation of the benefits, manufacture, and theories of metal-matrix composites. The article examines a few metal-matrix composites in depth, explaining at a molecular level why the composite material acts the way it does. The article details the manufacturing processes for the microfilaments, and finishes with a short look into the future of the role of `metal-matrix composites in the field of medicine.
Summary by N.V. Carter, Spring 1998.