Difference in cohesive zone model results peak force for the same input data

[abc123ali]

Respected ABAQUS Users, I have made two same cae abaqus cohesive zone model but just with a difference of surface to surface contact in one model and node to surface contact in another model gr8 and gr9 respectively in the interaction module and I got different results. Kindly solve this problem.These both model have 8 number of grooves. In the cohesive zone modelling of the grooved structure when there is increase in number of grooves it should come more cohesive force during the shear slipping of both plates but it reduces in one model but in another model it comes more using node to surface contact. Kindly update which one is correct or how to model correctly? The number of grooves in JobGRNTOSUR contains 4 grooves with node to surface interaction while the surface to surface is gr1fm has surface to surface interaction when this is compared with 8 groove model should have low cohesive peak force due to less area of contact but it is more than gr8 surface to surface contact. Also please tell me that the reference point I just made is rf1 while it appears as assembly constraint 3 reference point in xy obd field output element nodes section during extraction output. why?
Thanks for cooperation

 

[FEA way]

In practice, the main difference between surface to surface and node to surface contact is in the accuracy/uniformity of results such as contact pressure. So compare CPRESS and CSHEAR contour plots. You can also check other results such as COPEN and CSTATUS to see how contact works in those models.