Air Force Institute of Technology AFIT Scholar Theses and Dissertations Student Graduate Works 3-13-2006 Analysis and Simulation of Hypervelocity Gouging Impacts John D. Cinnamon Follow this and additional works at: https://scholar.afit.edu/etd Part of the Engineering Science and Materials Commons Recommended Citation Cinnamon, John D., "Analysis and Simulation of Hypervelocity Gouging Impacts" (2006). Theses and Dissertations. 3318. https://scholar.afit.edu/etd/3318 This Dissertation is brought to you for free and open access by the Student Graduate Works at AFIT Scholar. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of AFIT Scholar. For more information, please contact [email protected]. Analysis and Simulation of Hypervelocity Gouging Impacts DISSERTATION John D. Cinnamon, Major, USAF AFIT/DS/ENY/06-01 DEPARTMENT OF THE AIR FORCE AIR UNIVERSITY AIR FORCE INSTITUTE OF TECHNOLOGY Wright-Patterson Air Force Base, Ohio APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED. The views expressed in this work are those of the author and do not reflect the official policy or position of the Department of Defense or the United States Government. AFIT/DS/ENY/06-01 Analysis and Simulation of Hypervelocity Gouging Impacts DISSERTATION Presented to the Faculty Department of Aeronautics and Astronautics Graduate School of Engineering and Management Air Force Institute of Technology Air University Air Education and Training Command In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy John D. Cinnamon, B.S.E., M.S.E., P.E. Major, USAF June 2006 APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED. AFIT/DS/ENY/06-01 Abstract Hypervelocity impact is an area of extreme interest in the research community. The U.S. Air Force has a test facility at Holloman Air Force Base which specializes in hypervelocity impact testing. This Holloman AFB High Speed Test Track (HHSTT) is currently working toward a test vehicle speed above Mach 10. As the sled’s speed has increased to Mach 8.5, a material interaction develops which causes “gouging” in the rails or the sled’s “shoes” and this can result in catastrophic failure. Previous efforts in investigating this event have resulted in a choice of the most suitable computer code, (CTH), and a model of the shoe/rail interaction. However, the dynamic stress models of the specific materials were not developed and the model was not validated against experimentation. In this work, a summary of past and present research efforts, as well as the theoretical foundation of this field of study, are presented. A characterization of gouging is developed from an examination of a gouged rail from the HHSTT. A thermodynamic history of gouging is determined from the experimental evidence and an extensive study is performed that determines the specific material models. The developed material dynamic strength models are validated utilizing several experimental tests which are successfully simulated using CTH. Additionally, a pene- tration theory is developed which provides insight into the gouging problem using an analytic approach that does not require the use of computationally intensive codes. Based on the detailed examination of the materials and the validation of the material models within CTH, an evaluation of the HHSTT gouging phenomenon is performed. These simulations of the gouging problem replicate the experimentally observed characteristics and lead to recommendations to mitigate the occurrence of hypervelocity gouging. iv Table of Contents Page Abstract..................................... iv Acknowledgements ............................... vi ListofFigures ................................. xi ListofTables.................................. xix ListofSymbols................................. xxi ListofAbbreviations.............................. xxviii I. Hypervelocity Gouging Problem Overview . 1-1 II. Previous Research in the Hypervelocity Gouging Phenomenon . 2-1 2.1 DescriptionofGouging. .. .. 2-1 2.2 Previous Hypervelocity Gouging Research . 2-5 2.2.1 Test Track Observations and Gouging Tests . 2-5 2.2.2 LaboratoryGougingTests . 2-15 2.2.3 Numerical Modeling of Gouging . 2-22 2.2.4 Aerodynamic Sled Analysis . 2-32 2.2.5 LoadandFailureAnalysis . 2-35 2.2.6 MethodsforGougeMitigation . 2-38 2.3 SzmerekovskyModel . .. .. 2-41 2.4 SummaryofPreviousResearch . 2-43 III. TheoreticalBackground ....................... 3-1 3.1 Hypervelocity Impact Solution Procedure . 3-1 3.2 EquationofState...................... 3-4 3.3 ConstitutiveModels .................... 3-8 3.4 FailureModel........................ 3-12 IV. CharacterizationofGouging. .. .. 4-1 4.1 MethodologyforExaminingGouge . 4-1 4.2 Results of the Examination of Gouged Specimens . 4-3 4.3 AnalysisofGougeResults . 4-14 4.4 Conclusions on Gouged Specimen Examination . 4-23 4.5 ExaminationofRailCondition . 4-23 4.6 Gouge Characterization Conclusions . 4-30 vii Page V. Constitutive Model Development . 5-1 5.1 Constitutive Model Overview . 5-1 5.2 Split Hopkinson Bar Test . 5-2 5.2.1 SHBTestBackground . 5-2 5.2.2 SHBTestResults ................. 5-6 5.2.3 SHB-Based Constitutive Model Development . 5-10 5.3 Flyer Impact Plate Experiments . 5-13 5.3.1 Flyer Plate Experiment Background . 5-14 5.3.2 Flyer Plate-Based Constitutive Model Develop- ment........................ 5-17 5.4 Constitutive Model Summary . 5-28 VI. Validation of Constitutive Models for Mid-Range Strain-Rates . 6-1 6.1 ModelingtheSHBTests .................. 6-1 6.2 Metallurgical Verification of SHB Model Results . 6-6 6.3 TaylorImpactTests .................... 6-9 6.3.1 Taylor Test Overview . 6-10 6.3.2 TaylorTestResults . 6-12 6.3.3 Constitutive Model Validation via Taylor Tests 6-18 6.4 Study of HHSTT Coatings via Taylor Test . 6-19 6.4.1 Coated Taylor Impact Test Overview . 6-19 6.4.2 Coated Taylor Impact Test Results . 6-20 6.4.3 One Dimensional Theory for Coating Comparison using the Taylor Impact Test . 6-23 6.4.4 Constitutive Model Validation for Taylor Test Coated Specimens ..................... 6-28 6.5 Modeling of Taylor Impact Tests in CTH . 6-29 6.5.1 CTH Contact Schemes . 6-29 6.5.2 CTH Taylor Test Model . 6-31 6.5.3 CTH Modeling Conclusion . 6-32 6.6 Summary of Mid-Range Strain-Rate Model Validation . 6-34 VII. Scaled Laboratory Hypervelocity Gouging Test . 7-1 7.1 Scaled Gouging Test Development . 7-1 7.2 One-Dimensional Penetration Model . 7-8 7.2.1 Theoretical Foundations of the 1-D Penetration Model ....................... 7-8 7.2.2 Results from the 1-D Penetration Model . 7-16 7.2.3 Engineering Design Approach for using 1-D Pen- etrationModel .................. 7-19 7.2.4 Application of the 1-D Theory to the HHSTT GougingProblem ................. 7-24 viii Page 7.2.5 Application of the 1-D Theory to the Laboratory Hypervelocity Gouging Tests . 7-25 7.3 Laboratory Hypervelocity Gouging Experiments and Val- idation of the One-Dimensional Penetration Model . 7-26 7.4 Metallurgical Examination of Hypervelocity Gouging Test Results ........................... 7-34 7.5 Summary of Scaled Laboratory Hypervelocity Gouging Test ............................. 7-36 VIII. Validation of Constitutive Models for High Strain-Rates in Hyper- velocityImpact............................ 8-1 8.1 Examination of CTH Modeling . 8-1 8.1.1 ModelModeComparison. 8-4 8.1.2 Model Mode Comparison Summary . 8-7 8.2 Validation of CTH Hypervelocity Gouging Model . 8-8 8.2.1 CTH Model of Laboratory Hypervelocity Goug- ingTest ...................... 8-8 8.2.2 CTH Simulation of Laboratory Hypervelocity Goug- ingTest ...................... 8-9 8.2.3 CTH Simulation of Thermal Characteristics of the Laboratory Hypervelocity Gouging Test . 8-11 8.2.4 Further Results from the Comparison of CTH Simulations to the 1-D Penetration Theory . 8-13 8.2.5 Summary of Validation of CTH Hypervelocity Goug- ingModel ..................... 8-15 8.3 Validation of Constitutive Models and CTH for Hyperve- locityModeling....................... 8-17 IX. Simulation of HHSTT Hypervelocity Gouging Scenario . 9-1 9.1 CTH Modeling of the HHSTT Sled Scenario . 9-1 9.2 GougingCase1:VerticalImpact . 9-3 9.2.1 VerticalVelocityof2m/s . 9-3 9.2.2 VerticalVelocityof10m/s. 9-3 9.2.3 VerticalVelocityof40m/s. 9-5 9.2.4 VerticalVelocityof75m/s. 9-6 9.2.5 VerticalVelocityof100m/s . 9-9 9.2.6 Vertical Velocity of 30 m/s on 10% Surface Area 9-10 9.2.7 Vertical Velocity of 100 m/s with Heated Shoe . 9-11 9.2.8 Summary of Vertical Impact Case . 9-13 9.3 GougingCase2: AngledImpact. 9-14 9.3.1 Incidence Angle of 0.14◦ ............. 9-16 9.3.2 Incidence Angle of 1.65◦ ............. 9-17 ix Page 9.3.3 Incidence Angle of 3◦ ............... 9-19 9.3.4 Summary of Angled Impact Case . 9-20 9.4 Gouging Case 3: Rail Discontinuity . 9-21 9.4.1 0.01524cmRailDiscontinuity . 9-23 9.4.2 0.02cmRailDiscontinuity . 9-24 9.4.3 0.03048cmRailDiscontinuity . 9-26 9.4.4 Discontinuity with Varying Face Angle . 9-28 9.4.5 Summary of Rail Discontinuity Case . 9-35 9.5 HHSTT Hypervelocity Gouging Scenario Simulation Con- clusions ........................... 9-35 X. Conclusions.............................. 10-1 10.1 Review of Previous Research in the Field . 10-1 10.2 TheoreticalFoundations . 10-2 10.3 GougeCharacterization . 10-3 10.4 Development of Material Constitutive Models . 10-4 10.5 Validation of the Constitutive Models for Mid-Range Strain- Rates ............................ 10-5 10.6 Development of a Scaled Hypervelocity Impact Experiment 10-6 10.7 Validation of the Constitutive Models for High Strain-Rates 10-7 10.8 Simulation of the HHSTT Gouging Scenario . 10-8 10.9 ConcludingRemarks . 10-10 Appendix A. Sample Scaled Hypervelocity Impact CTH Input File . A-1 Appendix B. Sample Sled Simulation CTH Input File . B-1 Bibliography .................................. 1 x List of Figures Figure Page 1.1. Rocket Sled System at the HHSTT . 1-2 1.2. RocketSledShoe-RailInterface. 1-2 1.3. TypicalTotalRailFailure..................... 1-3 1.4. CatastrophicRocketSledFailure . 1-3 1.5. TypicalRailandShoeGouge................... 1-4 1.6. SchematicofTypicalRailGouge .