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Status Report 2 EVALUATION of RESIDUAL STRENGTH OF DOCUMENT NO: EFRC – ABS02 (1) FAA PROJECT NO: CURRENT REVISION: IR INITIAL DATE: 07/07/11 Status Report 2 EVALUATION OF RESIDUAL STRENGTH OF BEECHCRAFT BONANZA SPAR CARRY‐THROUGH WITH FATIGUE CRACKS Conducted for the AMERICAN BONANZA SOCIETY DEPARTMENT: Embry-Riddle Aeronautical University - Eagle Flight Research Center SECTION: Technical Analysis PREPARED BY: TECHNICAL APPROVAL: Snorri Gudmundsson PREPARED BY: MANAGER APPROVAL Richard P. Anderson REVISION APPROVAL REV REVISED BY APPROVED BY DATE REV REVISED BY APPROVED BY DATE IR SG RPA 07/07/11 1 2 3 REVISION HISTORY Revision DESCRIPTION OF CHANGE A Initial release Snorri Gudmundsson Principal Investigator: Assistant Professor of Aerospace Engineering Embry‐Riddle Aeronautical University Prepared by: Snorri Gudmundsson Research team supervisor: Dr. Eric Hill Research Team (alphabetical order by last name): Christopher Foti, Ning Leung, Zachary Sager, Michael Scheppa, Isadora Thisted, Joseph Tabarracci, Dr. Jean‐Michel Dhainaut. Contents 1. INTRODUCTION ......................................................................................................................................... 7 2. PROJECT TASKS .......................................................................................................................................... 7 3. LOAD TESTING ........................................................................................................................................... 7 GENERAL ...................................................................................................................................................................... 7 MOUNTING INTERFACE ................................................................................................................................................... 8 LOAD APPLICATION GIZMO .............................................................................................................................................. 8 APPLICATION OF LOADS ................................................................................................................................................... 9 STRAIN GAGES AND DATA ACQUISITION ............................................................................................................................. 9 EXPERIMENTAL PROCEDURE ........................................................................................................................................... 11 FIDELITY OF STRAIN GAGES DURING TEST .......................................................................................................................... 11 4. FINITE ELEMENT MODEL ........................................................................................................................... 13 GENERAL .................................................................................................................................................................... 13 MODEL CONSTRAINTS ................................................................................................................................................... 16 APPLICATION OF LOADS ................................................................................................................................................. 16 LIMITATIONS OF THE FE MODEL ...................................................................................................................................... 19 5. COMPARISON OF EXPERIMENT TO PREDICTION ........................................................................................ 20 COMPARISON OF STRAINS .............................................................................................................................................. 20 COMPARISON TO CLASSICAL STRESS ANALYSIS ................................................................................................................... 21 6. LOAD CASES .............................................................................................................................................. 23 LOAD CASE 1: SYMMETRICAL LOAD (12600 LBF) ON EACH WING .......................................................................................... 23 LOAD CASE 2: ASYMMETRICAL LOAD CASE 100/60 ........................................................................................................... 23 LOAD CASE 3: SYMMETRICAL TOUCH‐DOWN ON MAIN GEAR ONLY. ...................................................................................... 24 LOAD CASE 4: ASYMMETRICAL TOUCH‐DOWN ON MAIN GEAR ONLY. .................................................................................... 24 7. STRESS FIELDS AT LIMIT LOAD ................................................................................................................... 25 LOAD CASE 1: SYMMETRICAL LOAD (8400 LBF) ON EACH WING – LIMIT LOAD...................................................................... 26 LOAD CASE 2: ASYMMETRICAL LOAD CASE 100/60 – LIMIT LOAD ..................................................................................... 27 8. STRESS FIELDS AT ULTIMATE LOAD – BASELINE STRUCTURE ...................................................................... 28 LOAD CASE 1: SYMMETRICAL LOAD (12600 LBF) ON EACH WING – ULTIMATE LOAD ............................................................ 29 LOAD CASE 2: ASYMMETRICAL LOAD CASE 100/60 ........................................................................................................... 30 LOAD CASE 3: SYMMETRICAL TOUCH‐DOWN ON MAIN GEAR ONLY. ...................................................................................... 31 LOAD CASE 4: ASYMMETRICAL TOUCH‐DOWN ON MAIN GEAR ONLY. .................................................................................... 32 9. STRESS FIELDS AT ULTIMATE LOAD – 3.5” LONG CRACK ............................................................................. 33 LOAD CASE 1: SYMMETRICAL LOAD (12600 LBF) ON EACH WING – ULTIMATE LOAD ............................................................ 34 LOAD CASE 2: ASYMMETRICAL LOAD CASE 100/60 ........................................................................................................... 35 LOAD CASE 3: SYMMETRICAL TOUCH‐DOWN ON MAIN GEAR ONLY. ...................................................................................... 36 LOAD CASE 4: ASYMMETRICAL TOUCH‐DOWN ON MAIN GEAR ONLY. .................................................................................... 37 10. STRESS FIELDS AT ULTIMATE LOAD – CRACK THROUGH THREE FASTENERS ............................................ 38 LOAD CASE 1: SYMMETRICAL LOAD (12600 LBF) ON EACH WING – ULTIMATE LOAD ............................................................ 39 LOAD CASE 2: ASYMMETRICAL LOAD CASE 100/60 ........................................................................................................... 40 LOAD CASE 3: SYMMETRICAL TOUCH‐DOWN ON MAIN GEAR ONLY. ...................................................................................... 41 LOAD CASE 4: ASYMMETRICAL TOUCH‐DOWN ON MAIN GEAR ONLY. .................................................................................... 42 11. STRESS FIELDS IN SPARS AT ULTIMATE LOAD ......................................................................................... 43 12. CONCLUSION ........................................................................................................................................ 47 APPENDIX A: BEECH BONANZA DATA ................................................................................................................ 50 APPENDIX B: VON MISES YIELD CRITERION ........................................................................................................ 52 EVALUATION OF RESIDUAL STRENGTH OF BEECHCRAFT BONANZA SPAR CARRY‐THROUGH WITH FATIGUE CRACKS 1. INTRODUCTION This status report is considered the final deliverable in an investigation conducted by Embry‐Riddle Aeronautical University (ERAU) research faculty on behalf of the American Bonanza Society (ABS). The investigation is performed in accordance with ERAU Research Project 13776 (signed on 9/22/2010) and an agreement between ERAU and ABS presented in a Statement of Work (SOW). The precursor to this project and initial work is detailed in Reference 1, a report titled EFRC – ABS01, Evaluation of Residual Strength of Beechcraft Bonanza Spar Carry‐Through with Fatigue Cracks. This report details the tasks accomplished in the second phase of the project and its conclusion. 2. PROJECT TASKS The effort in the second phase consisted of the following tasks: 1. The spar carry‐through was load tested to obtain data for validation of a Finite Element (FE) model. The load testing is discussed in Section 3 of this report. 2. A FE model of the spar carry‐through was created using the solid modeler CATIA, and then meshed using the pre‐ and post‐processor FEMAP. This model is discussed in Section 4 of the report. 3. The FE solver NASTRAN was used to predict strains in the FE model using the test loads. A comparison of measured and predicted strains was conducted to evaluate the quality of the model and to better understand the nature of load paths. This validation is discussed in Section 5 of the report. 4. Four load cases to be applied to the FE model are discussed in Section 6 of this report. The load cases, which are detailed in the Reference 1 represent symmetric and asymmetric flight load cases and landing load cases. 5. The application of the four load
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