?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.relation=http%3A%2F%2Fd-scholarship-dev.library.pitt.edu%2F10611%2F&rft.title=NUMERICAL+MODELING+OF+ROCK+CUTTING+AND+ITS+ASSOCIATED+FRAGMENTATION+PROCESS+USING+THE+FINITE+ELEMENT+METHOD&rft.creator=Jaime%2C+Maria+Carolina&rft.description=As+the+need+for+reaching+fuel+reserves+at+greater+depths+increases%2C+over+the+past+30+years+scientists+have+been+exploring+and+developing+the+technology+required+to+efficiently+drill+rock+at+highly+pressured+environments%3B+yet%2C+there+are+still+gaps+in+the+understanding+of+the+physical+phenomena+involved.+One+of+the+basic+problems+has+to+do+with+the+cutter-to-rock+interaction+during+the+cutting+process.%0D%0A%0D%0AThis+study+employs+the+Finite+Element+Method+(FEM)+to+investigate+the+mechanics+of+rock+cutting+because+of+its+flexibility+in+handling+material+heterogeneity%2C+nonlinearity+and+boundary+conditions.+Using+the+FEM+to+model+fracturing+of+a+brittle+material+like+rock+%E2%80%93and+consequently+treating+its+discontinuous+chips%E2%80%93+is+a+challenging+undertaking+that+requires+the+tackling+of+a+sequence+of+complex+problems%3A+As+the+cutter+advances+and+touches+the+rock+material%2C+a+contact+problem+first+arises.+This+is+followed+by+nonlinear+deformation+and+the+determination+as+to+when+and+whether+the+rock+would+fail.+Subsequently%2C+the+question+of+how+to+initiate+the+fragmentation+process+has+to+be+resolved+if+the+rock+fails.+The+cycle+repeats+starting+with+a+new+contact+problem+after+new+surfaces+are+generated+due+to+fracture.+%0D%0A%0D%0AAt+present%2C+few+researchers+have+focused+on+crack+initiation+and+subsequent+crack+propagation%2C+but+even+fewer+have+accounted+for+actual+chip+formation%2C+and+none+has+considered+the+dynamic+interaction+amongst+chips%2C+newly+formed+surfaces%2C+and+the+cutter.+One+important+goal+of+this+study+is+to+advance+the+modeling+such+that+it+is+possible+to+follow+the+cutter+in+a+complete+cutting+process+in+a+credible+manner.%0D%0A%0D%0AA+framework+of+three-dimensional+FEM+modeling+was+developed+so+that+the+fragmentation+process+observed+in+laboratory+rock+scratching+tests+could+be+properly+simulated.+A+thorough+calibration+of+the+rock+material+model+was+carried+out%2C+together+with+extensive+sensitivity+analyses+of+contact+models%2C+damage+based+failure+and+its+associated+fracture+modeling+using+the+commercial+software+LS-DYNA.+%0D%0A%0D%0AThis+study+was+able+to+obtain+ductile+failure+mode+for+shallow+cuts%2C+and+brittle+failure+for+deep+cuts+as+observed+in+the+laboratory%2C+all+without+a+priori+setting+on+the+failure+modes.+Also%2C+cutting+force+magnitudes+and+tendencies+obtained+from+the+study+correlated+well+with+published+results+of+the+physical+experiments.+Moreover%2C+in+a+limited+scope%2C+this+study+also+investigated+the+effects+of+applying+external+hydrostatic+pressure+on+rock+cutting.+Preliminary+numerical+results+indicate+a+good+comparison+with+few+published+data.+Lastly%2C+theoretical+models+for+obtaining+cutting+forces+were+assessed%2C+providing+a+better+understanding+of+their+limitations+and+usability.%0D%0A&rft.date=2012-02-02&rft.type=University+of+Pittsburgh+ETD&rft.type=PeerReviewed&rft.format=application%2Fpdf&rft.language=en&rft.identifier=http%3A%2F%2Fd-scholarship-dev.library.pitt.edu%2F10611%2F1%2FJaime_Maria_PhD_diss_ETD_Nov30_11.pdf&rft.identifier=++Jaime%2C+Maria+Carolina++(2012)+NUMERICAL+MODELING+OF+ROCK+CUTTING+AND+ITS+ASSOCIATED+FRAGMENTATION+PROCESS+USING+THE+FINITE+ELEMENT+METHOD.++Doctoral+Dissertation%2C+University+of+Pittsburgh.++++(Unpublished)++