Module 6 None-Metallic Materials Objective Six Flashcards
Isotropic Properties
Properties are all in the same direction
Ec=
KEfVf+EmVm
K
a factor representing fiber-reinforcing efficiency
Ec
the modulus of elasticity for the final composite
Ef
the modulus of elasticity for the fibre
Em
he modulus of elasticity for the final matrix
Vf
the volume fraction of the fibre
Vf+Vm=1
Vm
The volume fraction of the matrix
Vf+Vm=1
Anisotropic Property
the properties are orientation dependent
Lc
critical fibre length, the necessary length to provide enough interfacial bonding between the matrix and the fibers
Lc=
(σuf*d)/(2Tc)
σuf
ultimate tensile strength of the fiber
Tc
the smaller value of the fiber matrix bond strength or the matrix shear yield strength
d
fiber diameter
> 15 Lc
long or continuous fibres
<15 Lc
short or discontinuous fibres
modulus of elasticity of composite material in the longitudinal direction
Ec=EmVm + EfVf
Density
p
Thermal Conductivity
K
Density calculation
pc=pmVm + pfVf
Thermal Conductivity Equation
Kc=KmVm + KfVf
ratio of load carried by the fibre to the load carried by the matrix
Ff/Fm = (EfVf)/(EmVm)
Stress in composite material at any level before failure σc=
σc= σmVm + σfVf
σuc=
σ’mVm + σufVf
σ’m
the stress in the matrix after the fibre fails
