Mechanical properties in composite materials, Mechanical Engineering

Composite materials consist of two or more distinct components.  Generally we refer to a matrix and a reinforcement.  The reinforcement can be in the form of fibres (continuous or discontinuous) or particles.

To a reasonable approximation, discontinuous (short) fibre and particulate reinforced composites can be treated by the engineer in the same way as any homogeneous isotropic material.  Fibre reinforced composites need to be considered quite differently.  In most cases they are still viewed as homogeneous (i.e. the properties in any given direction are an average value), but anisotropy (direction dependence) of properties cannot be ignored. 

In general, when working with a continuous fibre reinforced material, the engineer must select the lay-up of composite to be used as part of the design process.  The processing route to be used must also be considered at an early stage.

We first consider unidirectional material.

Mechanical Properties of Unidirectional Laminates

Q1 If you are working with a metal, what elastic properties do you need in order to calculate strains (deflections) of a structure under generalised in-plane loading?  Write down the stress-strain relationship for an element of material which experiences stresses σx, σy, τxy in an x-y coordinate system.

Q2 What property data do you need (for a metal) in order to ensure that your design loads will not cause plastic deformation (yielding)?  What are the most widely used yield criteria?

Consider now that you are working with a unidirectional fibre composite material in an engineering application.  Conventionally, the direction along the fibres is the '1' direction and perpendicular to the fibres is the '2' direction.

2080_matrix.png

Principal directions in unidirectional laminate.

Q3  What stiffness and strength property data would be needed to carry out a basic static mechanical design on such a piece of composite material?

Posted Date: 2/21/2013 7:57:55 AM | Location : United States







Related Discussions:- Mechanical properties in composite materials, Assignment Help, Ask Question on Mechanical properties in composite materials, Get Answer, Expert's Help, Mechanical properties in composite materials Discussions

Write discussion on Mechanical properties in composite materials
Your posts are moderated
Related Questions
This section covers welding of pressure parts including those non-pressure parts when welded to pressure parts. All welding design functions necessary within the contract shall be

Determine maximum stress and modulus of elasticity:  A composite of glass fibres and epoxy has all of fibres laid along the length and is needed to carry a stress of 12 MPa. T

How does the Two Stage Reciprocating Air Compressor works?

Neutra l Layer and Neutral Axis In the beam or cantilever, there is one layer which retains the original length of it even after bending. So in this layer tensile stress and c

a) Describe and illustrate the terms with their classification: Mechanism, Kinematic, Machine links and Kinematic pair. b) Discuss the Inversions of double slider crank chain an

Determine elongation because of self weight of tapering rod: Sol.: Take a tapering rod hung vertically and firmly fixed at top position. The rod is of length L tapers unifor

The rigidly jointed frame shown in Figure has bending stiffnesses such that EI AB = 1000kNm 2 and EI BC = EICD = 1600kNm 2 . (i) Determine the joint rotations at B and C.

Evaluate force and moment: What force and moment is transmitted to supporting wall at A   A force of 15 KN is transmitted to wall along with anticlockwise mome

Location with Respect to Depth The depth below ground level at which the bottom of a foundation structure is located depends on number of factors, the most important of which

defect of casting