Light Truck Frame Joint Stiffness Study Phase 1 Final Report

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CORRELATION Introduction Correlating the test and analysis results required multiple iterations. In the literature search, 15-30% was the average range of deviation between test and analysis. This average percent came from a combination of papers, including Fragoso, 1993. The joint stiffness study deviation between test and analysis is well within that range. Correlating the Test and Analysis Data Initially, the fixtures were modeled with rigid elements due to the assumed rigidity of the loading fixture, and the deflections were measured using similar triangles. This meant that the location, and in some cases, the direction of the deflections measured between test and analysis, were not the same. But through geometry, the same rotations and thus stiffness could be calculated. The problem with this approach is that because of out of plane rotations in the joint and a slight influence of the loading fixture on the deflection of the crossmember, the finite element model did not correlate well. By including the fixture in the finite element model the deflections were measured at the same point as in the test. This proved to be critical for accurate test/analysis correlation and lowered our deviations by providing a more representative model of the physical test. The main deviation between the model and test occurred from not modeling surface contact at fixture interfaces, resulting in local deflection in the finite element model of the loading fixture base plate. Increasing plate thickness from 3/8 to 3/4 inch in both test and analysis and retesting resulted in good correlation between the two. The test data had not changed but the finite element analysis results were brought into the same range as the test results. The final percent difference between the test and analysis results is shown in Table 3. Graphs of each loadcase for the five joints, comparing the test and analytical results can be found in the appendix. Report: A/SP-005-1 Light Truck Frame Joint Stiffness Study 47
CORRELATION Table 3: Test and Analysis Joint Stiffness Correlation Summary Joint 1: Tube-Through-Tube (welded at both ends) % Deviation Between Test and Analysis Joint Stiffness Kx Ky Kz 21.92% -22.46% 2.39% Joint 2: Box to Lipped Channel -6.56% -23.62% 23.32% Joint 3: Tube Through Partially Boxed Section (welded on both sides) 2.12% -24.36% -3.96% Joint 4: Alligator to Box Section (welded to both flanges) -16.63% -23.50% -19.65% Joint 5: Hat Section to Box Section (welded all around) 15.44% -11.25% 5.79% * The negative indicates analytical results lower than test Report: A/SP-005-1 Light Truck Frame Joint Stiffness Study 48
Page 1 and 2: Light Truck Frame Joint Stiffness S
Page 3 and 4: EXECUTIVE SUMMARY Background There
Page 5 and 6: TABLE OF CONTENTS Introduction ....
Page 7 and 8: LITERATURE SEARCH Introduction A li
Page 9 and 10: LITERATURE SEARCH Joint Stiffness T
Page 11 and 12: FINITE ELEMENT ANALYSIS Introductio
Page 13 and 14: FINITE ELEMENT ANALYSIS Defining th
Page 15 and 16: FINITE ELEMENT ANALYSIS Load Applie
Page 17 and 18: FINITE ELEMENT ANALYSIS z L: Load F
Page 19 and 20: FINITE ELEMENT ANALYSIS Table 1: An
Page 21 and 22: TESTING PROCEDURE Test Repeatabilit
Page 23 and 24: TESTING PROCEDURE Joints 1 - 4 Pneu
Page 25 and 26: TESTING PROCEDURE Joint 1 - X Direc
Page 27 and 28: TESTING PROCEDURE Joint 1 - Torsion
Page 41 and 42: TESTING PROCEDURE Joint 5 - Hanging
Page 43 and 44: TESTING PROCEDURE Joint 5 - Z Direc
Page 45 and 46: TESTING PROCEDURE Joint Stiffness S
Page 47: TESTING PROCEDURE Table 2: Test Joi
Page 51 and 52: SENSITIVITY STUDY The influence of
Page 53 and 54: SENSITIVITY STUDY C- Channel Gage C
Page 55 and 56: SENSITIVITY STUDY C- Channel Gage C
Page 57 and 58: SENSITIVITY STUDY Crossmember Gage
Page 59 and 60: JOINT STIFFNESS TOOLBOX Introductio
Page 61 and 62: JOINT STIFFNESS TOOLBOX Notes: * Mo
Page 71 and 72: APPENDIX A: ABSTRACTS Read Articles
Page 73 and 74: APPENDIX A: ABSTRACTS 7. SCF Design
Page 75 and 76: APPENDIX A: ABSTRACTS 15. Deformati
Page 77 and 78: APPENDIX A: ABSTRACTS reasonable ag
Page 79 and 80: APPENDIX A: ABSTRACTS frequency err
Page 81 and 82: APPENDIX A: ABSTRACTS 36. Dynamic R
Page 83 and 84: APPENDIX A: ABSTRACTS 43. Behavior
Page 85 and 86: APPENDIX A: ABSTRACTS 6. Connection
Page 87 and 88: APPENDIX B: MATERIAL TESTING REPORT
Page 99 and 100:
APPENDIX B: MATERIAL TESTING REPORT
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APPENDIX C: TEST RESULTS Joint 1 Fo
Page 113 and 114:
APPENDIX C: TEST RESULTS Joint 2 Ve
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APPENDIX C: TEST RESULTS Joint 3 To
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APPENDIX C: TEST RESULTS Joint 5 Fo
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APPENDIX D: DIAGRAM OF JOINT IN TES
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Light Truck Frame Joint Stiffness Study Phase 1 Final Report

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