Modeling the Sliding of a Hard Wedge on a Metal Substrate

Ernesto Gutierrez-MiraveteRensselaer at Hartford

CCAT- Summer 2010

Problem Description• A hard, rigid carbide wedge (semi-angle = )

moving at constant speed V encounters a metal block (breadth =b, hardness = H) and begins to slide over its surface to a certain depth = d, under plane strain conditions for a total sliding length = L.

• Initially, a prow forms in front of the sliding wedge and is pushed by it (plowing).

• The prow grows in size and eventually may transform into a chip that is in turn ejected in front of the wedge (cutting).

Plowing vs Cutting

Friction Coefficient due to Plastic Deformation during Plowing

• Tangential Force: Ft = H d b

• Normal Force:Fn = H d b tan

• Friction Coefficient: = Ft/Fn = cot

• For the case herein considered = 45 degrees so = 1

Finite Element Model

• AdvantEdge (Third Wave Systems Inc.) is a commercial implementation of the finite element method designed to analyze the behavior of metals encountered during machining operations

• The code embodies an explicit scheme capable of modeling coupled, non-linear thermo-mechanics at large strains and strain rates incorporating constitutive deformation behavior, contact, friction, fracture and adaptive meshing.

Systems Investigated• The following alloy systems were investigated. The

material property databases included in the software were used. The value of the friction coefficient in the code was set to 0.

Al-6061-T6 1020 Steel

Cu-37700 BrassTi6Al4V

• Other parameter values were as follows:d = 0.005 mm; V = 10 m/s; L = 0.1 mm

Results- Al6061

Results –1020 Steel

Results – Cu 37700

Results – Ti6Al4V

Summary• In all cases considered, the computed normal forces

were larger than the tangential forces.• Friction coefficient values calculated from the

computed forces where in all cases within 10-20% of the expected value of 1.

• Both, tangential and normal forces obtained under cutting conditions decreased to about ~80% of their values exhibited during plowing conditions.

• The point of transition from plowing to cutting is material dependent.

Modeling the Sliding of a Hard WedgeErnesto Gutierrez-Miravete

Rensselaer-Hartford