The technology isn’t a new one though. For years composites or sandwich panels have been used in the manufacture of both civilian and military aircraft and more recently used in racing vehicles, ship building and even specialized architecture. A typical Boeing civil airliner may be comprised of up to 5-15% composite panel, although recently Boeing announced that the new 7E7 would be composed of up to 50% composite, making it ultra light weight while maintaining optimum durability.
The success of composite technology in the aviation field has made it attractive to other industries seeking to apply the benefits. One of the more significant for the trucking profession is that core composite materials measure in much lighter than steel and aluminium with an average weight savings of up to 40% over steel and 20% over aluminium.
At present, composite technology can be applied to body panels and accessories, front-end panels, floor, engine block, cargo liners, vehicle chassis, bumper beams, fuel tank supports, heat-resistant parts such as inlet manifold, cooling modules, and oil pan… Heavy wood or metal decking on trailers may be replaced with sandwich panel to further shed pounds and leverage added payload and longer trailer deck life. Diversity in the materials used and in the manufacturing process enables composite panels to be fashioned into flat or curved forms that possess one of the highest strength to weight ratios of any structural material available on the market.
Replacing just a class 8 sleeper box with custom manufactured composite panel technology can reduce overall vehicle weight by up to 850 pounds, effectively decreasing gross weight and fluid resistance while increasing payload.
In addition to lightweight composition, the sound dampening and insulation properties create a quiet environment inside the sleeper; corrosion resistance, and overall durability are also high on the ratings scale.
The panels are formed when two materials are combined to create a stronger substance than either of the two base materials on their own. The panels themselves are heated and thermo fused to the matrix or core; the matrix binds together the fibres of the stronger material, called the reinforcement. The reinforcement can be engineered from glass fibre, aramid and carbon whereas the matrix can comprise polyester resins, vinyl ester resins, or epoxy resins, as well as many light fibre materials. The separation of the skins by this low-density core increases the moment of inertia of the beam or panel with very little increase in weight, producing a highly efficient structure. Throughout the extensive use of high strength adhesives, composite panels are precisely joined together providing superior enhancements in relationship to conventional riveting or welding processes. Staying ahead from conventional practices allows the industry to perceive tangible savings linked to lower direct labour cost, tooling, equipment but mainly eliminating expensive rust and corrosion issues or claims.
Essentially the strength of the composite panel depends on its overall size, the surface material used, and the density of the cells inside it, the thicker the core, the higher the stiffness and strength of the panel. By careful selection of reinforcement, matrix and production process, manufacturers are able to produce industry specific composite panels. Composites designed for heavy commercial applications such as aircraft manufacturing, aerospace industry, oil exploration and military markets utilize high-strength, continuous fibres such as polyurethane foam or other dynamic materials to ensure a rigid panel that can withstand wear and tear due to loading stresses or mechanical strain. For low strength and stiffness or low stress applications such as automotive, marine, and industrial parts, a matrix composed of non-continuous fibres like paper or card can be used ensuring optimum strength-to-weight ration for the particular application.
By varying composition and thickness, compressive and tensile strength and resistance to deflection keep damage from rocks and debris as well as stress in loading and unloading to a minimum. If damage does occur, panel replacement is relatively easy and affordable and can be repaired at most auto-body repair facilities.
A generic composite panel is generally described as:
Some overall benefits are:
- Lighter (but strong) materials provide lower fuel consumption
- Can be customized to many specific applications
- Relatively fast implementation times
- Noise dampening properties block out ambient noise from outside the interior
- Resistant to harmful chemicals and heat
- They last longer
- Minimized structural noise
From a manufacturing or engineering standpoint:
- When shock and impact loads are an issue the honeycomb cell size can be adjusted to achieve different compression strengths.
- Working prototypes using laminated panels and sandwich panels can be developed to within 4-6 weeks of inception. The manufacturing processes is geared to maximum efficiency and optimum implementation times
- The insulation value (R value) can range from 2.5 to up to 6 depending on the thickness of the panels. Specific customer requirements can be achieved through the use of special honeycomb cores and facings
- The range of materials used to manufacture panels to specification makes it an attractive option for truck manufacturers
- Versatility of design in body and door panels, hoods, roof panels, bonnets, and spoilers allow for drastic reduction in fluid drag and rolling resistance.
Ongoing research and development is providing continuous advancements in composite performance and expanding the range of applications. The transportation industry is welcoming composite technology which may soon replace wood and metal as the material of choice.
Edison Reis, B.Sc. Eng.
Engineering & Quality Assurance Manager
Canadian Commercial Vehicles Corp.