CDM Design Exam Questions and Answers 100% Pass

CDM Design Exam Questions and Answers 100% Pass List three advatanges of composites - Design: Lighter, stiffer, stronger, more corrosion resistant Manufacture: fewer components, fewer fasteners and fwer processes required How can high material and manufacturing costs be overcome by design and manufacture? - Use of composites reduces components, fasteners and manufacturing processes, therefore a well designed uses less materials and thus reduced components/fasteners/labour costs Suggest three type of form of material and section configuration examples illustrated in introduction notes - De haviland abatross (1937) - wodden composite structure Mosuqiteo (1940) - wooden laminated skin sandiwch with balsawood core and male contrete tooling 2100% Pass Guarantee Katelyn Whitman, All Rights Reserved © 2025 Spitfire (1940s) - coton/flax phenolic composite to create spitfire demonstrator Harrier GRS: BAE model with monolithic carbon fibre/epoxy wings by co-bonding and co-curing Gerhard Waibel ASW 22B: glider w/ hybrid glass/carbon fibre epoxy composite wing and fuselage Westland Augusta EH101: helicopter tailored carbon fibre eppxy BERP w/ metal mould Wing turbines: hybrid of glass and carbon fibre epoxy laminates manufacturing in open moulds Blank - Blank Name 5 typical consitutents of composite materials - Fibre Matrix Interface 3100% Pass Guarantee Katelyn Whitman, All Rights Reserved © 2025 Core Adhesive What arrangement and form of fibre is needed for advanced composite materials? - Aligned, continuous fibre reinforcement What is a tow? - A bundle of strands where a strand is a bundle of filaments (a filament is a fibre) Name three types of carbon fibre - High modulus Intermediate modulus High strength State the main attributes of carbon, kevlar and glass fibres - Carbon: graphic type crystals, typically high strength and high stiffness, brittle Kevlar: aromatic polymer fibre, high tensile strength, high stiffness, fibrillation under compression, exhibit more necking than others thus tougher characteristics Glass: amorphouse structure, high strength, moderate stiffness, strain to failure of 2% 4100% Pass Guarantee Katelyn Whitman, All Rights Reserved © 2025 State main limiting properties of carbon, kevlar and glass - Carbon: low strain to failure (1 - 1.5%), brittle Kevlar: moisture ingress, fibrillation under high compression Glass: moderate stiffness and higher density than carbon Choose either carbon, glass or kevlar for: Impact Specific stiffness/strength Low cost - Impact: Kevlar specific: carbon low cost: glass Name two main types of polymer matrices and give examples of each - Thermoset: epoxies Thermoplastic: PEEK State three main differences between thermoset and thermoplastic composites - Thermoset: cross linked, chemical reaction occurs, cannot be re-softened 5100% Pass Guarantee Katelyn Whitman, All Rights Reserved © 2025 Thermoplastic: not all of the above State three advantages of thermoset composites - Commonly used in composite aerospace structures as easier to manufacturing General mechanical properties are better than thermoplastics (i.e. stronger) Generally inexpensive as they don't need as much heat/pressure State three advantages of thermoplastic composite - Inifite shelf life Can be re-softened (recycling/scrapping is much easier) Little or no volatile organic compounds and no cure time