However, the technology is not new. For years, composites or sandwich panels have been used in the manufacture of both civil and military aircraft and, more recently, in racing vehicles, shipbuilding and even specialized architecture. A typical Boeing civil aircraft can be made up of up to 5-15% composite panels, although Boeing recently announced that the new 7E7 would be made up of up to 50% composites, making it ultralight while maintaining optimum durability.
The success of composite technology in the aviation field has made it attractive to other industries looking to apply the benefits. One of the most significant for the trucking profession is that core composite materials are much lighter than steel and aluminum with average weight savings of up to 40% over steel and 20% over aluminum .
At present, the composite technology can be applied to body panels and accessories, front panels, floor, engine block, cargo liners, vehicle chassis, bumper beams, engine mounts, etc. fuel tank, heat resistant parts such as intake manifold, cooling modules and oil pan… Heavy wood or metal decking on trailers can be replaced with sandwich panels to further reduce poundage and take advantage of the additional payload and extend the life of the trailer cover. The diversity in the materials used and in the manufacturing process allows composite panels to be made into flat or curved shapes that possess one of the highest strength-to-weight ratios of any structural material available on the market.
Replacing just one Class 8 sleeper box with custom fabricated composite panel technology can reduce overall vehicle weight by up to 850 pounds, effectively reducing gross weight and fluid resistance while increasing payload.
In addition to the lightweight composition, the sound insulating and deadening properties create a calm environment within the sleeper; Corrosion resistance and overall durability are also high on the ratings scale.
Panels are formed when two materials are combined to create a substance stronger than either of the two base materials alone. The panels themselves are heated and thermofused to the matrix or core; the matrix binds the fibers of the stronger material together, called reinforcement. The reinforcement can be designed from fiberglass, aramid, and carbon, while the matrix can comprise polyester resins, vinyl ester resins, or epoxy resins, as well as many lightweight fiber materials. The separation of the skins by this low-density core increases the moment of inertia of the beam or panel with very little weight gain, producing a highly efficient structure. Through extensive use of high-strength adhesives, composite panels are precisely joined providing superior improvements over conventional welding or riveting processes. Staying ahead of conventional practices allows the industry to realize tangible savings associated with lower direct labor, tooling and equipment costs, but primarily eliminates costly rust and corrosion problems or claims.
Essentially, the strength of the composite panel depends on its overall size, the surface material used, and the density of the cells within it; the thicker the core, the greater the rigidity and strength of the panel. Through careful selection of the reinforcement, matrix, and production process, manufacturers can produce industry-specific composite panels. Composites designed for heavy-duty commercial applications such as aircraft manufacturing, aerospace, oil exploration, and military markets use high-strength continuous fibers such as polyurethane foam or other dynamic materials to ensure a rigid panel that can withstand wear and tear due to to load stresses or mechanical stress. For low strength and stiffness or low stress applications, such as automotive, marine and industrial parts, a matrix composed of non-continuous fibers such as paper or cardboard can be used, ensuring an optimal strength-to-weight ratio for the particular application.
By varying the composition and thickness, compressive and tensile strength, and deflection strength minimize damage from rocks and debris, as well as stress during loading and unloading. If damage occurs, panel replacement is relatively easy and affordable and can be repaired at most auto body repair facilities.
A generic composite panel is usually described as:
Some general benefits are:
- Lighter (but stronger) materials provide lower fuel consumption
- Can be customized for many specific applications
- Relatively fast implementation times
- Noise dampening properties block outside ambient noise from inside.
- Resistant to harmful chemicals and heat.
- last longer
- Minimized structural noise
From a manufacturing or engineering standpoint:
- When shock and impact loads are an issue, the size of the honeycomb cell can be adjusted to achieve different compression forces.
- Working prototypes using laminated panels and sandwich panels can be developed within 4-6 weeks of start-up. The manufacturing processes are oriented towards maximum efficiency and optimum execution times.
- The insulation value (R-value) can vary from 2.5 to 6 depending on the thickness of the panels. Customer specific requirements can be achieved through the use of special honeycomb cores and skins
- The range of materials used to fabricate panels to specification makes it an attractive option for truck manufacturers.
- Design versatility in the body and door panels, hood, roof panels, bonnets and spoilers allow for a drastic reduction in rolling resistance and fluid drag. Ongoing research and development provide continuous advances in compound performance and broaden the range of applications. The transportation industry is welcoming composite technology that may soon replace wood and metal as the material of choice.
Edison Reis, B.Sc.Eng.
Engineering and Quality Assurance Manager
Canadian Commercial Vehicle Corporation.
www.ccvbc.com