DEVELOPMENT OF ANALYSIS TOOL FOR HIGH AND LOW VELOCITY ICE INDENTATION PROBLEMS

TWO MAJOR OBSTACLES CONFRONTED PREVIOUS ATTEMPTS TO ANALYZE FIELD ICE BEHAVIOR; NAMELY: THE LACK OF PROPER CONSTITUTIVE LAWS TO MODEL REALISTIC ICE BEHAVIOR, PARTICULARLY AT HIGH STRAIN-RATES, AND THE DIFFICULTY IN INCORPORATING LARGE ICE DEFORMATIONS IN THE ANALYSIS. THIS PROPOSAL PRESENTS A STUDY WHICH WILL IMPLEMENT AN ICE CONSTITUTIVE MODEL SUBROUTINE TO WORK IN CONJUNCTION WITH A LAGRANGE EXPLICIT FINITE-DIFFERENCE NUMERICAL SOLUTION SCHEME, WHICH IS CAPABLE OF HANDLING TRANSIENT, LARGE DISPLACEMENT AND LARGE STRAIN PROBLEMS. SPECIFIC OBJECTIVES OF THE PHASE I STUDY ARE: (1) DEVELOP A CONSISTENT SET OF METHODOLOGIES TO PREDICT THEICE BEHAVIOR AND FORCES ASSOCIATED WITH PENETRATION OF A RIGID SPHERICAL OR FLAT INDENTER INTO A FLAT ICE WALL AT HIGH VELOCITIES. THE CONSTITUTIVE MODEL WILL BE AN EXTENSION AND REFINEMENT OF TWO MODELS FOR LOW AND HIGH STRAIN-RATES, RESPECTIVELY, WHICH HAVE ALREADY BEEN PRESENTED BY THE PRINCIPAL INVESTIGATOR. (2) PRESENT COMPARISON OF PREDICTED INDENTATION BEHAVIOR AT HIGH AND LOW VELOCITIES. (3) DISCUSS GENERALIZATION OF METHODOLOGIES TO OTHER GEOMETRIES, VELOCITY RANGES, AND LARGER CONTACT AREAS, PARTICULARLY FOR CONDITIONS RELEVANT TO FIELD ICE LOADING ONOFFSHORE STRUCTURES.