Composite Materials - Multiple Choice

What is the role of the Matrix component in the composite material?

the matrix supports the fibers and bonds them together

What do the structural properties such as stiffness, dimmensional stability, and strength of a composite laminate depend on?

the stacking sequence of the piles

In this ply orientation, the plies are stacked in a 0, -45 and 90 degrees sequence or in a 0, -60 and + 60 degree sequences. These types of ply orientation simulate the properties of an ____ material

isotropic

Unidirectional tape products have what physical properties?

high tensile strength in the fiber direction

Kevlar is DuPont's trademark name for what type of fibers?

Aramid

What is the primary advantage of Aramid fibers?

resistant to impact damage

If the graphene layers or planes stack with a two dimensional order, the material is defined as?

carbon

What is required for aircraft carbon fiber parts that are prone to lightning strike?

lightning protection

What are Ceramic fibers used for on aircraft?

turbine blades

Where are Bismaleimide (BMI) resins used?

high temperature components

Most honeycomb materials are ______ ; that is, properties are directional.

anisotropic

Honeycomb core cells for aerospace applications are typically what shape?

Hexagon

What is considered to be the optimal fiber to resin ratio?

60:40

What type of inspection is the primary method for in-service inspections of composite materials?

visual

What causes delaminations to form?

matrix cracks

On what type of composite structure is tap testing most effective?

honeycomb sandwich with thin face sheets

What Ultrasonic Inspection method uses two transducers, one on each side of the area to be inspected?

through transmission

What Ultrasonic Inspection method uses a single search unit as a transmitting and receiving transducer that is excited by high voltage pulses?

pulse echo

What is the typical storage life for prepreg material?

6 to 12 months

What is used to improve the peel strength of co-bonded assemblies?

film adhesive

What is considered to be a permanent repair?

Meets the strength requirements and the durability requirements

A potted repair is for ____?

small repairs to honeycomb structure

What condition could affect the signal of the aircraft radar?

trapped water in the aircraft radome

Honeycomb sandwich structures are often repaired with

scarf type bonded repair

What is an individual fiber called?

Filament

What three terms are commonly used to describe a bundle of filaments?

Tows, yarns, roving

What is required for aircraft carbon fiber parts that are prone to lightning strike?

lightning protection mesh or coating

What cure temperatures do Polyamides require?

High cure temperatures in excess of 550 degrees fahrenheit

What shape are honeycomb over-expanded core cells?

rectangles

Scarf type repairs use ____ scarf angles to ease the load into the repair

small