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n. through-thickness stress. [K] relates stress to separation. t. transverse shear. membrane shear. s. Cohesive modeling in ABAQUS. . 3D Cohesive Element. = { d n , d s , d t }/T 0. Cohesive modeling in ABAQUS. Viscous Regularization. - represents the relaxation time
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n through-thickness stress [K] relates stress to separation t transverse shear membrane shear s Cohesive modeling in ABAQUS . 3D Cohesive Element = {dn, ds, dt }/T0
Cohesive modeling in ABAQUS Viscous Regularization • - represents the relaxation time • D - stiffness degradation variable of the inviscid system • Dv - stiffness degradation variable of the viscous system • Important Assumption - the viscous system relaxes to the inviscid system as t/m ∞ • Advantage - tangent stiffness matrix, during the softening regime, is positive for small time increments
Linking FRANC3DNG and ABAQUS for interface fracture • For all elements in mesh: • For all faces on element: • Store the element pair sharing the face and the face nodes • For all element pairs stored: • If element material id #s are different • Store bimaterial interface nodes and elements • For all interface nodes stored: • Create 2 duplicates of the node • For all interface elements stored: • Reconnect elements with duplicate nodes • Create interface elements
Verification and realistic models tested Applied displacement = 0.015 inch Traction, psi/inch 100 Material #1 1e7 Material #2 0.015 d, inch
Model results – compare with previous slide d x 0.015 inch
Additional items Investigation of viscous regularization solver technique to speed calculations has been completed. Currently working on code for the insertion of a distribution of particles (locations and sizes) into a matrix on the topological level.
Wish List • From MD simulation, when does the crack grow along the boundary and when does it nucleate? 20 m