$***$Please describe the layered elastic model that should be used and any equations used. Please create a plot or plots of the varying data

$5.(20$ points$)$ Given: Tire load $=9000$ lbs$,$ and tire pressure $=100$ psi. Pavement structure is as follows. Use one of the layered elastic models to determine Nf and then evaluate the effects of the following changes while holding all other variables constant: $(1)$ vary the HMA thickness from $1$ to $8$ inches; $(2)$ vary the UAB modulus from $10,000$ psi to $100,000$ psi; $(3)$ vary Poisson's ratio of the HMA from $0\mathrm{.}2,0\mathrm{.}35,$ and $0\mathrm{.}5$; and $(4)$ vary the tire pressure from $60$ psi to $120$ psi in $20$ psi increments. Plot and discuss results.