contact problems

I am modelling a very simple 2D contact problem between a rigid wedge indenter and a deformable squared-shape specimen (general steel material) in frictionless contact case. I used an implicit function f to describe the rigid indenter.

I implemented Lagrange multiplier method for this contact problem and the contact condition is: Inside the contact zone of the deformable specimen, the node set is active if f(node)<=0 and the Lagrange multiplier lambda<=0.

Dear all,
In my FE model (pin on disc), I would like to define a contact property between pin and disc with a friction defination available in ABAQUS. I have assumed that friction coefficient depends on parameters like slip rate, pressure and temperature only. When i used friction coefficients with slip rate and pressure, model works without any error but if i use friction coefficients with slip rate, pressure and temperature, the model doesn't work and come up with following errors;