The Fiber Properties & Their Importance In Aerospace Industry

The table shows that for designing an aerospace material the material must have some of the engineering property to perform it in the end use exposure condition. The general properties of the fiber include Thermal properties, Durability, Health/safety/protection, Comfort, Maintenance and Miscellaneous properties. There are several methods or engineering terms are used to evaluate and compare the general fiber properties.

Thermal Properties

Thermal properties are compared and evaluated by below engineering terms- Specific Heat means energy required to raise the temperature of a unit mass of the substance by one degree and Thermal conductivity is defined as the rate of heat transfer through a unit thickness of the material per unit area per temperature difference. Thermal resistance is a heat property and a measurement of a temperature difference by which an object or material resists a heat flow.Softening point is the temperature at which a material softens sufficiently to allow significant flow under a small stress and melting is the temperature at which the body starts melting.

Combustibility is a measure of how easily a substance bursts into flame, through fire or combustion. An aerospace vehicle while flying above 40,000 ft. of the sea level undergoes several temperature conditions. It varies from -70oc to +60oc. So this must be made sure that the material sustain well enough in this temperature condition without affecting its performance. And we can test its performance in different temperature conditions these specific heat, thermal conductivity, heat resistance, Softening and melting and combustibility.

Durability

Strength elongation is calculated by tensile test , conducted to determine tensile strength, yield strength and elongation of a material. Also, the stress strain curve obtained from this test gives the idea of Flexibility and elastic recovery. The aero plane while flying goes thru different layers of the atmosphere where air pressure varies a lot from layer to layer. Air pressure drops about 3.5 millibars per 30 meters (100 feet) as altitude increases. Also the plane carrying goods or passenger undergoes a specific loading conditions in varying air pressure. So it is important to check the strength , Elongation ,Flexibility and elastic recovery of the fiber material used to avoid any accident while flying in varying load and pressure conditions.

Health/safety/Protection

The performance of health/safety for aerospace material is measured by Sound absorbency (how absorbent the material is) and how resistant the material is to UV radiation which is compared by SPF (Sun protective factor). The sound produced by the aero plane engine varies in between 80-100 Db. Whereas sound less than 75 Db can cause hearing loss if exposed for prolonged hours. So this is very important the material to be sound absorbent so that the sound does not enter the cabin and causes any problem to the passenger. Also, most airplanes fly at >40k feet, way into the stratosphere / mesosphere where sun's UV rays aren't filtered by lower atmospheric layers. So, it is very important for an aerospace material to be UV protective to ensure the health and safety of the passengers.

Comfort

Comfort in aerospace engineering means how easily the material can float and is evaluated by Weight per unit volume. Also, the less the weight of the material less the fuel consumption, the less will be per hour flying cost. So, this is very important from commercial point of view as well as for the performance on the aircraft.

Miscellaneous Properties

While flying sometimes the aircraft faces critical weather conditions with lightning storm. An average bolt of lightning, striking from cloud, contains roughly one billion (1,000,000,000) joules of energy so the aerospace material must be shock/electrical resistant enough to withstand the situation. Resistance to shock(lightening) is measured by electrical resistivity i.e. property of a material that quantifies how strongly that material opposes the flow of electric current.

Aesthetic and Maintenance

Two more properties that is also important is performance in color and dust. The aircraft are always nicely painted with different colors and logos . So this is important that the material has a good color absorbency and this color lasts long in varying atmospheric conditions. And people always prefer to see the aircraft clean so it will be easier for maintenance part if the material exhibit high soil propensity. Though this is not essential but it really adds value to the material chosen.

Textile fiber that can be used in aerospace industry

Using fiber composite in aerospace industry can be beneficial due its light weight that causes less fuel consumption. But the application of the fiber in aerospace industry are still in research process. Below are few materials that can be a good replacement of the currently used aluminum alloys.

Carbon fiber

Carbon fiber is stronger than steel, lighter than aluminum, and can be formed into any shape the computational fluid dynamics programs, so it will be good for a lightweight and low-drag airplane.

Glass fiber

Glass fibers as the base material and a resin matrix, can be another substitute for aerospace engineering. It is important to avoid fire when using composite materials because the resin used weakens and causes release of toxic fumes. So, application of resins and their properties need to be studied to improve its performance.

Aramid fiber

Aramid fibers are heat-resistant and flame-resistant so can be used as a preferred over glass fiber from safety point of view.