?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%2F17904%2F&rft.title=Numerical+Modeling+of+Rock+Drilling+With+Finite+Elements&rft.creator=Zhou%2C+Yaneng&rft.description=Rock+drilling+is+the+process+employed+to+retrieve+both+the+conventional+and+the+unconventional+resources%2C+such+as+gas+and+oil+buried+deep+under+the+ground.+This+study+attempts+to+improve+the+understanding+of+the+interaction+between+the+drilling+bit+and+rock+by+investigating+the+mechanics+involved.+In+terms+of+achieving+such+a+goal%2C+a+numerical+modeling%2C+if+successful%2C+can+provide+insights+that+are+not+possible+through+either+field+tests+or+laboratory+experiments.%0D%0AWhen+the+cutting+depth+progresses+from+shallow+to+deep%2C+there+is+a+failure+mode+transition+from+ductile+to+brittle%2C+and+a+critical+depth+that+governs+this+transition.+This+study+introduced+Ba%C5%BEant%E2%80%99s+simple+size+effect+law+into+interpreting+the+transition+process+of+rock+cutting.+By+treating+the+cutting+depth+as+a+measure+of+size%2C+the+law+was+found+applied+well+to+rock+cutting+based+upon+the+data+available+in+the+literature%2C+and+the+Finite+Element+Method+(FEM)+modeling+results.+By+introducing+the+concept+of+characteristic+length%2C+this+study+also+reinterpreted+the+previous+understanding+of+the+critical+depth+in+rock+cutting%2C+by+introducing+the+concept+of+characteristic+length%2C+and+obtained+the+influence+of+characteristic+length+on+critical+depth+through+numerical+modeling.+%0D%0AThe+Mechanical+Specific+Energy+(MSE)+and+the+Rate+of+Penetration+(ROP)+are+two+key+factors+for+evaluating+the+efficiency+of+a+drilling+process+and+together+they+form+a+good+base+for+strategizing+a+desirable+drilling+operation.+In+the+absence+of+cutter+wear+rate%2C+a+relationship+between+MSE+and+ROP+for+a+rectangular+cutter+has+previously+been+suggested.+This+study+presented+a+simple+model+for+a+circular+cutter+that+includes+the+wear+progression%2C+which+could+explain+the+laboratory+result+of+cutting+high+strength+rock+under+high+pressure.%0D%0AThe+operation+of+a+drilling+bit+in+the+field+is+mainly+achieved+through+circular+cutting+action.+This+study+extended+the+previous+efforts+and+modeled+first+the+circular+cutting+of+a+single+disc+cutter.+This+effort+then+formed+the+basis+of+a+full+drilling+bit+modeling+presented+at+the+end.+%0D%0A&rft.date=2013-06-28&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%2F17904%2F1%2FZhou_etdPitt2013.pdf&rft.identifier=++Zhou%2C+Yaneng++(2013)+Numerical+Modeling+of+Rock+Drilling+With+Finite+Elements.++Doctoral+Dissertation%2C+University+of+Pittsburgh.++++(Unpublished)++