MIL-HDBK-17-3F Volume 3.Foreword Table of Contents 3.5.2.2 Business case.... 22 3.5.2.3 Divergence and risk... 22 3.5.2.4 Technical acceptability22 3.5.2.5 Allowables development and equivalency validation ........................... 22 3.5.2.6 Production readiness................... 22 3.5.2.7 Less0 ns learned… 22 3.5.3 Divergence and risk............. 22 3.5.3.1 Divergence.......... 24 3.5.3.2 Risk assessment............... 25 3.5.3.3 Risk analysis.. 4.4...... 26 3.5.4 Production readiness...... 26 CHAPTER 4 BUILDING BLOCK APPROACH FOR COMPOSITE STRUCTURES.... 1 4.1 INTRODUCTION AND PHILOSOPHY.......... 1 4.2 RATIONALE AND ASSUMPTIONS................... 4 4.3 METHODOLOGY.......... .5 4.3.1 General approach... 5 4.4 CONSIDERATIONS FOR SPECIFIC APPLICATIONS.......................................... 6 4.4.1 Aircraft for prototypes ................ 0.6 4.4.1.1 PMC composite allowables generation for DOD/NASA prototype aircraft structure....... .6 4.4.1.2 PMC composites building block structural development for DOD/NASA prototype aircraft........ 10 4.4.1.3 Summary of allowables and building block test efforts for DOD/NASA prototype composite aircraft structure................15 4.4.2 Aircraft for EMD and production...... .15 4.4.2.1 PMC composite allowables generation for DOD/NASA EMD and production aircraft structure.. 15 4.4.2.2 PMC composite building block structural development for DOD/NASA EMD and production aircraft.......... .19 4.4.2.3 Summary of allowables and building block test efforts for DOD/NASA EMD and production composite aircraft structure.................4 4.4.3 Commercial aircraft................ 24 4.4.3.1 Introduction… 24 4.4.3.2 The building block approach....24 4.4.3.2.1 certification approaches................. .25 4.4.3.2.2 Allowables versus design values..... 26 4.4.3.23 Lamina vs.laminate derived allowables for predicting strength...........26 4.4.3.2.4 Product development27 4.4.3.3 Composite road map......... 27 4.4.3.3.1 Criteria.… 28 4.4.3.3.2 Regulations.… 28 4.4.3.4 Commercial building block approach..29 4.4.3.5 Group A,material property development...... .29 4.4.3.5.1 Block 1-material screening and selection..... 30 4.4.3.5.2 Block 2-material and process specification development................... 30 4.4.3.5.3 Block 3-allowables development ,30 4.4.3.6 Group B,design-value development...........31 4.4.3.6.1 Block 4-structural element tests.......................31 4.4.3.6.2 Block 5-subcomponent tests. 33 4.4.3.7 Group C,analysis verification... 33 4.4.3.7.1 Block 6-component test.34 4.4.3.8 Boeing 777 aircraft composite primary structure building block approach. 34 4.4.3.8.1 Introduction................ 34MIL-HDBK-17-3F Volume 3, Foreword / Table of Contents vi 3.5.2.2 Business case.................................................................................................. 22 3.5.2.3 Divergence and risk......................................................................................... 22 3.5.2.4 Technical acceptability..................................................................................... 22 3.5.2.5 Allowables development and equivalency validation ...................................... 22 3.5.2.6 Production readiness....................................................................................... 22 3.5.2.7 Lessons learned .............................................................................................. 22 3.5.3 Divergence and risk ....................................................................................................... 22 3.5.3.1 Divergence....................................................................................................... 24 3.5.3.2 Risk assessment.............................................................................................. 25 3.5.3.3 Risk analysis.................................................................................................... 26 3.5.4 Production readiness..................................................................................................... 26 CHAPTER 4 BUILDING BLOCK APPROACH FOR COMPOSITE STRUCTURES........................... 1 4.1 INTRODUCTION AND PHILOSOPHY....................................................................................... 1 4.2 RATIONALE AND ASSUMPTIONS............................................................................................ 4 4.3 METHODOLOGY....................................................................................................................... 5 4.3.1 General approach ............................................................................................................ 5 4.4 CONSIDERATIONS FOR SPECIFIC APPLICATIONS.............................................................. 6 4.4.1 Aircraft for prototypes ...................................................................................................... 6 4.4.1.1 PMC composite allowables generation for DOD/NASA prototype aircraft structure................................................................................................. 6 4.4.1.2 PMC composites building block structural development for DOD/NASA prototype aircraft .......................................................................... 10 4.4.1.3 Summary of allowables and building block test efforts for DOD/NASA prototype composite aircraft structure ......................................... 15 4.4.2 Aircraft for EMD and production .................................................................................... 15 4.4.2.1 PMC composite allowables generation for DOD/NASA EMD and production aircraft structure............................................................................. 15 4.4.2.2 PMC composite building block structural development for DOD/NASA EMD and production aircraft ........................................................ 19 4.4.2.3 Summary of allowables and building block test efforts for DOD/NASA EMD and production composite aircraft structure........................ 24 4.4.3 Commercial aircraft........................................................................................................ 24 4.4.3.1 Introduction ...................................................................................................... 24 4.4.3.2 The building block approach............................................................................ 24 4.4.3.2.1 Certification approaches ....................................................................... 25 4.4.3.2.2 Allowables versus design values .......................................................... 26 4.4.3.2.3 Lamina vs. laminate derived allowables for predicting strength ........... 26 4.4.3.2.4 Product development ............................................................................ 27 4.4.3.3 Composite road map ....................................................................................... 27 4.4.3.3.1 Criteria................................................................................................... 28 4.4.3.3.2 Regulations ........................................................................................... 28 4.4.3.4 Commercial building block approach............................................................... 29 4.4.3.5 Group A, material property development......................................................... 29 4.4.3.5.1 Block 1 - material screening and selection ........................................... 30 4.4.3.5.2 Block 2 - material and process specification development................... 30 4.4.3.5.3 Block 3 - allowables development ........................................................ 30 4.4.3.6 Group B, design-value development ............................................................... 31 4.4.3.6.1 Block 4 - structural element tests.......................................................... 31 4.4.3.6.2 Block 5 - subcomponent tests............................................................... 33 4.4.3.7 Group C, analysis verification.......................................................................... 33 4.4.3.7.1 Block 6 - component test ...................................................................... 34 4.4.3.8 Boeing 777 aircraft composite primary structure building block approach.......................................................................................................... 34 4.4.3.8.1 Introduction ........................................................................................... 34