A Quick Review
- lightweight
- The fiber/resin mix can be customized to meet stiffness, strength and manufacturing requirements
- Part consolidation means a reduced number of assemblies and a reduced fastener count
- Reduced machining
- Tapered sections and compound contours easily accomplished
- Resistant to corrosion
- Resistant to fatigue damage with good damping characteristics
- Low coefficient of thermal expansion
Where It Counts…
Weight: Composites, due to lower density, can deliver a weight savings of 25 to 50 percent over traditional materials. Composite densities range from 0.045 lb/in3 to 0.072 lb/in3 as compared to 0.10 lb/in3 for aluminum and 0.29 lb/in3 for steel. While some applications may require thicker composite sections to meet strength/stiffness requirements, manufacturers will still enjoy a significant weight reduction.
Part consolidation: Composites allow a designer to go to the next level – beyond material substitution – to produce true composite parts and complex shapes. Composite material also makes it possible for a manufacturer to consolidate many parts in an assembly into one part - a major benefit. As a result, the part count along with fasteners, assembly time and weight, is reduced. Fiber reinforcement is able to maintain adequate strength and enhance reliability by eliminating interfaces since the attachment areas of parts are where the majority of failures occur due to high point loads and stress concentrations.
Cost: Composites are cost competitive when compared to metals due to low cost, high volume manufacturing methods that are being developed. Tooling costs and production labor time is similar. Typically, the higher cost of composite parts is largely due to high raw material costs. But selection of the optimal material for the part (not the best material) will control these costs. Judicious selection of suppliers can also minimize the cost penalty.
Composite performance: Composites provide improved performance benefits over metals due to their inherent properties. The strength-to-weight and stiffness-to-weight ratios are the primary reasons composites are used. The fiber reinforcements provide good damping characteristics and high resistance to fatigue. Most resins provide very good resistance to chemicals and corrosion. The fracture toughness of composites is significantly better than aluminum castings. By their nature, castings basically have built-in notches that can catastrophically fracture under impact. The fiber reinforcement of composites changes this failure sequence; resulting in an increased resistance to impact. The impact toughness of composites can be maximized by fiber selection, length of fiber and use of tougher resin such as thermoplastics. The wide range of fibers and resins available, makes it possible for manufacturers to choose the optimal material combination to meet the specific structural requirements of an application.
To learn more about composites and their applications click on Education to see the classes and training NCC offers.