The usage of the porosity model

[CalLightmanCode]

Dear LLNL/spheral:
I have used the spheral to simulate an impact scenario where an aluminum box impacts the basalt box. The Equations of State is TillotsonEquationOfState and the strength model is ConstantStrength. How can I use the Porosity Models in Spheral? For example, the strain-based porosity model (spheral/src/SolidMaterial/PorousStrengthModel.hh, spheral/src/SolidMaterial/PorousEquationOfState.hh). Thanks for your kindness helping.

My code is illustrated as follows:

eosAl = TillotsonEquationOfState(materialName = "aluminum",
                                etamin = etamin,
                                etamax = etamax,
                                units = units)
strengthAl = ConstantStrength(materialName = "aluminum",
                              units = units)
rho0Al = eosAl.referenceDensity

 porositystrengthAl= PorousStrengthModel(strengthAl)
 porosityeosAl= PorousEquationOfState(eosAl)

porositymodel = StrainPorosity(porosityeosAl,porositystrengthAl,AsteroidNode,
                                         phi0 = porosity,                 # Initial porosity
                                         epsE = 0.0,                 # Elastic-plastic transition strain
                                         epsX = -0.4,                # Threshold strain between compaction regimes
                                         kappa = 0.8,                # Compaction rate
                                        gammaS0 = 2.7,              # Reference gamma at full density
                                         cS0 = 0.522,                # Reference sound speed at full density
                                         c0 = 0.522 * 1.0)           # Reference sound speed at initial porosity
 output("porositymodel")
integrator = CheapSynchronousRK2Integrator(db)
integrator.appendPhysicsPackage(hydro)
integrator.appendPhysicsPackage(damageModel)
integrator.appendPhysicsPackage(porositymodel)

Although the porosity parameters can be read in VISIT, the crater has no difference between varied Initial porosity. I wonder if I have any mistakes in the usage of the porosity model.