cohesive simulation in abaqus

Hi all ,

       I am simulating Cohesive zone simulation of polymer coated steel using abaqus 6.9 ( Room Temp ).  The thickness of steel plate is 0.8mm ( 800 Micrometre). Thickness of PET ( Poly Polyethylene terephthalate ) is 0.03 mm ( 30 micrometre ). Cohesive zone is defined in between these two materials with zero thickness. I use standard traction seperation method embedded in abaqus 6.9. I have the following questions

(a) Regarding material properties,

1. I have given steel properties with elastic-plastic material type

2. Which material type I should use for PET ( Poly Polyethylene terephthalate ). presently I am assigning PET material properties like steel ( Since it is thermo plastic and my research is at room temp ). Is that the right way.? Is any other standard material type available in abaqus. Please clarify. No standard article is available regarding this

(b) Regarding simulation,

1. To create cohesive zone , should we create composite of steel and polymer first then we need to assign cohesive zone ? or can we create cohesive zone modeling directly without creating composite ?

1. I created a orphan mesh in steel surface which faces PET and defined cohesive elements with that. I havent given any constraints between steel and PET. Which type of constraints should I give? In my case  , the stell is base . Over that , polymer layer is fixed. In between this two material , cohesive zone has been assigned.

Please clarify these questions. I am striving hard to simulate this.

 Sincerely ,

Manivannan