Aerospace manufacturers have relied on the use of composites for more than 40 years to produce lightweight and durable components of airplanes and other vehicles. Historically, composites supplemented secondary aircraft structures, but recent technological advances enabled their use in primary aircraft structure components including fuselage, wings, doors, nacelles, tail structures, and more. For example, composite materials form nearly 50% of the Boeing 787’s construction by weight.
As with all aerospace materials, manufacturers must quality test their composites at every step of the process—from design to final product—to ensure that parts and components remain free of damage and compliant with a broad spectrum of industry standards. Composite testing also analyzes the composite’s structure to make sure that it has properly cured, as air bubbles or improper layering can cause cracks and catastrophic failures. Missing defects or design flaws in parts made from composites can severely damage your reputation and brand, not to mention potentially harm equipment, personnel, and passengers.
Here’s 5 of the top composite testing methods for establishing materials characteristics:
Areal Weight Testing
Areal weight (Af) calculates the mass of a part per unit area. In aerospace applications, air resistance depends on a part’s area, while gravitational force depends on mass. Therefore, determining a composite’s areal weight helps manufacturers find its material suitability for a specific application. Calculating the Af in composites can be especially challenging due to the measurement variance caused by laminated layers, which is based on both the radius of the fiber in a cross section and the fiber’s density.
A key step in material selection and component analysis, bend testing assesses composites for ductility, strength, fracture resistance, and fracture strength when bent at differing angles. This form of testing helps assess the efficacy of area welds, ensuring that proper fusion has been achieved.
Compressive Properties via Multiple Specifications
Aerospace components will often be exposed to extreme stresses and pressures. Compressive property testing analyzes the capacity of a material or structure to withstand loads that may crush, compact, or squeeze a material or part. This testing series assesses the composite’s compression and shearing properties, and it also provides compressive modulus, and compressive strength data.
Our compressive property testing complies with ASTM D6641 testing methodology for measuring combined loads on a material sample.
Constituent Content by Volume or Mass (Resin, Fiber, and Void)
This test provides an in-depth statistical model of a composite’s material properties along with how their intended application will affect them. This test evaluates the fabrication processes of composite materials, and it also helps us assess the quality of the finished material upon completion. Test results confirm a composite’s fatigue resistance, susceptibility to moisture penetration, and ability to withstand exposure to extreme environments, temperatures, and other conditions.
Dynamic Mechanical Analysis (DMA)
Given the broad spectrum of conditional tolerances required by most aerospace components, DMA testing characterizes a material’s properties, such as stiffness, as a function of temperature, time, frequency, stress, or atmosphere.
This list is not comprehensive, there are several other materials testing methods for composites. We will be publishing Parts 2 and 3 soon.