Scholars' Mine Doctoral Dissertations Student Theses and Dissertations 1970 Penetration in granite by shaped charge liners of various metals Hemendra Nath Kalia Follow this and additional works at: https://scholarsmine.mst.edu/doctoral_dissertations Part of the Mining Engineering Commons Department: Mining Engineering Recommended Citation Kalia, Hemendra Nath, "Penetration in granite by shaped charge liners of various metals" (1970). Doctoral Dissertations. 2038. https://scholarsmine.mst.edu/doctoral_dissertations/2038 This thesis is brought to you by Scholars' Mine, a service of the Missouri S&T Library and Learning Resources. This work is protected by U. S. Copyright Law. Unauthorized use including reproduction for redistribution requires the permission of the copyright holder. For more information, please contact [email protected]. PENETRATION IN GRANITE BY SHAPED CHARGE LINERS OF VARIOUS METALS by HEMENDRA NATH KALlA, 1939 A DISSERTATION Presented to the Faculty of the Graduate School of the UNIVERSITY OF MISSOURI-ROLLA In Partial Fulfillment of the Require~ts for the Degree DOCTOR OF PHILOSOPHY in MINING ENGINEERING T2388 1970 c. I 92 pages 193955 i i ABSTRACT The penetration in Missouri red granite by cylindrical charges with metal liners of aluminum 2011 (T-3), aluminum 7075 (T-6), yellow brass, monel, maraging steel (vascomax 250), and copper was measured. Metals having high ductility and moderate compressive strength penetrated deeper than high strength maraging steel. Aluminum required a greater standoff for optimum penetration than the other metal liners tested. Preliminary metallographic studies of the liner metals and slugs showed that the grains had elongated along the slug axis. The metals containing zinc formed very small or no slugs. The granite grains were highly fractured. The holes were dis­ colored and coated with jet metal. Penetration was affected by bedding planes and joints in the rock. Jet characteristics could not be photographed using a high speed framing camera because the view was obscured by the luminous front created by shock waves. Jet tip velocities were measured by pin oscilloscope techniques and were in the range of 7.91 - 9.83 millimeters per microsecond. The rate of penetration in granite was also obtained in this same manner. A mathematical expression was developed to calculate collapse time of cones using three-dimensional collapse criteria. ; ; i ACKNOWLEDGMENT The author considers it a privilege to express his gratitude to Dr. R. R. Rollins and Dr. G. B. Clark for their invaluable support and suggestions throughout this investigation. He is also grateful to E. I. Dupont De Nemours Company, and the United States Government, Department of Defense, for their financial support under fund number DACA-45-69-C-0087. Sincere thanks are extended to Dr. J. B. Clark, Dr. W. A. Frad, Mr. s. Vora and Mr. S. G. Bankar for their help in obtaining metal­ lographs; to Dr. E. L. Bertrand for his help in measuring slug densities; and to Dr. C. J. Haas for his assistance in calibrating the pin oscilloscope for velocity measurements. He is grateful to Mr. B. Hale for machining the liners, to Mr. E. Rapier, and Mr. E. Packheiser, for their aid in performing the experiments. Finally he extends his appreciation to his parents for their patience and thoughtfulness throughout his study period. iv TABLE OF CONTENTS Page ABSTRACT • .•.•.•••••••.•••.••••...••• " •..••.•.. ~ • ~ . • • • • . • . i i ACKNOWLEDGEMENT • •••••••.•••••••••••••••••• , • . • • • . • • . • • • • • • . • • i i i LIST OF ILLUSTRATIONS......................................... vi LIST OF TABLES.~ ...•.•........... ,............................ viii I. INTRODUCTION .• .•.•. ~ . • . • . • . • . • . • . • . • . • . • . 1 A. Genera 1 .•.........•..... , . • . 1 B. Nature of Investigation.............................. 2 II. THEORY OF JET FORMATION AND PENETRATION.................. 3 A. Theory of Cone Collapse and Jet Formation............ 3 B. Theory of Jet Penetration.. • . • .. • . • . .. 5 III. EXPERIMENTAL DESIGN ..................... ,............... 9 A. Design of Shaped Charges............................. 9 1 . Liner Materia 1 . 9 2. Apex Ang 1e . •.•.•.....•.•.........•• " ......... , . 10 3. Liner Th i cknes s . • . • . • . • . • . • . • . 10 4. Charge Dimensions............................... 12 5. Types of Explosives .......................... ,.. 12 6. Target Material................................. 13 IV. EXPERIMENTAL WORK AND RESULTS. • . • . • . • . • . • . • . 21 A. Penetration Studies and Penetration Data............. 21 1. Penetration Results. .. .. • . .. .. • . • .. .. 21 v Page B. Effect of Annealing on Liner Metals.................. 28 C. Jet Characteristics and Jet Tip Velocity............. 43 D. Mechanics of Penetration. • . • . • . • . 46 E. Slug Formation and Metallographic Observations....... 49 F. Nature of Holes in Granite........................... 52 V. SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS................. 56 APPENDIX A. List of Symbols.................................. 58 APPENDIX B. Derivation of Collapse Time and Kinetic Energy Expressions . • . • . • . • . • . • • • . • . • • . • . 60 APPENDIXC. Instrumentation.................................. 63 APPENDIX D. Metallography of the Metals and Slugs............ 67 REFERENCES • ...................................................... _. 81 VITA.............................................................. 84 vi LIST OF ILLUSTRATIONS Figure Page l. Cone Collapse and Jet Formation ................... ,....... 4 2. Cone Collapse Dimensions ... ,.............................. 4 3. Co 11 apse Time for 50 Degree Liners. • . • . 6 4. Fully Developed Detonation Front 28 ~sec after Initiation .................... ~·~~·····················-···"' 22 5. Penetration in Missouri Red Granite by 60 Degree Aluminum 2011 (T-3) Liners................................ 35 6. Penetration in Missouri Red Granite by 60 Degree Aluminum 7075 (T-6) Liners................................ 36 7. Penetration in Missouri Red Granite by 60 Degree Yellow Brass Liners ....... "'······································ 37 8. Penetration in Missouri Red Granite by 60 Degree Mone 1 L.i ners. 38 9. Penetration in Missouri Red Granite by 60 Degree Maraging Steel Liners .•...............•.•........... ,.... 39 10. Penetration in Missouri Red Granite by 42 Degree Copper Liners ....................... ~..................... 40 11. Penetration in Granite by Various Liners Tested.......... 41 12. Shaped Charge Jet 26 ~sees after Initiation............. 43 13. Jet Tip Velocity through Granite Blocks •............•... ; 45 14. Detonation Front and Associated Shock Wave 52 ~sec after Initiation .............................. ,.......... 47 15. Fracture Pattern in Granite.. • . • .. .. .. .. 49 16. Subsurface Fractures in Concrete ....•.•..... \ . 50 17. Longitudinal Section of the Shaped Charge Hole........... 50 18. Framing Camera Record of Cone Co 11 apse. .. • . • . .. .. .. 51 vii Figure Page 19. Photomicrograph of Copper imbedded in Granite............. 53 20. Photomicrograph of Steel Inclusion of Inner Wall of a Hole in the Granite.................................. 53 21. Typical Hole Profiles in Granite.......................... 55 lC. Arrangement to Photograph Jet Characteristics and Target Response ..•. .............. ! • • • • • • • • .. • • • • .• • • • • • • • • • • 65 10. Meta 11 ograph of A1 umi num 2011 . .. .. • . .. .. 72 20. Meta 11 ograph of A1 umi num Slug.. .. .. • . .. • . • . .. 72 30. Meta 11 ograph of A1 umi num 7075 .......................... , . 73 40. Meta 11 ograph of Ye 11 ow Brass... • . .. • . • . .. .. .. .. 73 50. Metallograph at the side of slug, Yellow Brass............ 74 60. Metallograph of Copper.................................... 74 70. Metallograph of Copper Slug............................... 75 80. Photomicrograph of Mane 1 . • . • . 75 90. Photomicrograph of Monel Slug. Taken along the Transverse Axis ..................•................. , . 76 100. Metallograph of the Center of the Monel Slug.............. 76 110. Metallograph of Monel Slug along the Transverse Axis ..... , 77 120. Metallograph of Steel..................................... 77 130. Meta 11 ograph of Stee 1 Slug ........................ , . .. 78 140. Steel Slug and its Hardness ...•................. ,......... 79 150. Metallograph of Maraging Steel Slug at Edge of Slug........................................................... 80 160. Metallograph taken at Center of Slug ..•.....•.•. ,......... 80 viii LIST OF TABLES Table No. Page 1 . Phys i ca 1 properties of the 1i ner meta 1s. • . • . • . • . • . 11 2. Shaped ... Charge explosives.................................... 14 3. Properties of Composition c.. 4. • • . • . • . • . • . • . • . • . • . • . 17 4. Physical properties of the target material.................. 18 5. Penetration in concrete by 60 degree 1i ners •.•...•. , .•.•.•. , 19 6, Penetration in rhyolite by 60 degree liners................. 20 7. Optimum standoff ...................................... ,..... 23 8. Penetration in granite by various liners tested at optimum standoff for 60 degree liners ......••••..... ,....... 24 9. Penetration in granite by 60 degree aluminum 2011 (T -3) Liners . •.....•.....................•....... tf ••••• 1; • • • • 29 10. Penetration in granite by 60 degree aluminum 7075 (T -6) Liners. 30 11. Penetration in granite by 60 degree yellow brass liners ....................................................... 31 12. Penetration in granite by 60 degree