One of the challenges for Airbus preparing a new freighter development process was the design of a solid freighter barrier, which separates the courier area from the cargo compartment. The major task of such a barrier is to protect the passengers against all risks caused due to cargo impact by a justifiable design. These risks may result from all kind of survivable incident and accident scenarios. Real aircraft crashes were analyzed to get away from a static book-case and come to a more realistic dynamic crash scenario. A reduced-order simulation model was built up to investigate and simulate the dynamic effects during crash. The simulation model considers the highly nonlinear stiffness and damping characteristics of all critical cargo types and also includes their energy absorption potentials. A series of full scale container crash tests have been performed at accredited car crash facilities. The test campaigns were complemented by numerous component tests to study also general crash principles. The critical simulation parameters were identified and implemented into the simulation model. The subsequent validation process showed a close agreement between simulation and test. The simulation environment has turned out to be a reliable basis to simulate all critical barrier loads with respect to the specific aircraft loading distributions. The essence of this investigation is an adequate understanding of the real crash effects. The proposed dynamic crash approach is more realistic than the static condition and results in an optimized safety barrier wall concept. This dynamic approach provides equivalent safety compared to the existing devices and is accepted by FAA and EASA.

One of the challenges for Airbus preparing a new freighter development process was the design of a solid freighter barrier, which separates the courier area from the cargo compartment. The major task of such a barrier is to protect the passengers against all risks caused due to cargo impact by a justifiable design. These risks may result from all kind of survivable incident and accident scenarios. Real aircraft crashes were analyzed to get away from a static book-case and come to a more realistic dynamic crash scenario. A reduced-order simulation model was built up to investigate and simulate the dynamic effects during crash. The simulation model considers the highly nonlinear stiffness and damping characteristics of all critical cargo types and also includes their energy absorption potentials. A series of full scale container crash tests have been performed at accredited car crash facilities. The test campaigns were complemented by numerous component tests to study also general crash principles. The critical simulation parameters were identified and implemented into the simulation model. The subsequent validation process showed a close agreement between simulation and test. The simulation environment has turned out to be a reliable basis to simulate all critical barrier loads with respect to the specific aircraft loading distributions. The essence of this investigation is an adequate understanding of the real crash effects. The proposed dynamic crash approach is more realistic than the static condition and results in an optimized safety barrier wall concept. This dynamic approach provides equivalent safety compared to the existing devices and is accepted by FAA and EASA.:Contents 1 Scope of the Work 1 1.1 State-of-the-Art Barrier Design 1 1.2 General Crash Justification Requirement 2 1.3 Barrier Protection Criterion 3 1.4 Proposed Dynamic Approach for an Optimized Safety Barrier Design 4 2 Simulation 6 2.1 About this Chapter 6 2.2 Simulation environment Matlab/Simulink 7 2.3 Simulation Model 7 2.4 Differential Equation 11 2.5 Stiffness and Damping 14 2.6 Crash Pulses 17 2.7 Dynamic Latch Behavior 21 2.8 Model Implementation 21 2.8.1 Derivation of the Equation Set Up for One Cargo Unit 22 2.9 Simulation Environment 25 3 Full Scale ULD Crash Tests 33 3.1 About this Chapter 33 3.2 Objectives 33 3.3 Test Setup 34 3.3.1 Cargo Configuration 34 3.3.2 Test Configuration 38 3.3.3 Test Equipment 39 4 Analysis of ULD Crash Tests 41 4.1 Test Results 41 4.1.1 Test with frangible Cargo 41 4.1.2 Test with rigid Cargo 45 4.2 Measurement Quality 47 4.3 Load Principles 50 4.4 Load Propagation on Barrier 52 5 Parameter Identification and Results 53 5.1 About this Chapter 53 5.2 Identification Process 53 5.3 Stiffness and Damping Identification 56 5.3.1 Identification of first ULD characteristic 57 5.3.2 Identification of second and aft ULDs 58 5.3.3 Identified Load-De ection Characteristics 59 5.4 Model Validation 60 6 Barrier Protection against Rigid Cargo Impact 63 6.1 About this Chapter 63 6.2 Excitation Pulse 64 6.3 State-of-the-Art Consideration 65 VIII CONTENTS 6.4 Simulation Model based on Energy Method 67 6.5 Reduced Crushable Cargo owing to Rigid Cargo Tests 70 7 Full Scale Latch Rupture Test 74 7.1 About this Chapter 74 7.2 Objectives 75 7.3 Test Setup 76 7.3.1 Tested Cargo 78 7.3.2 Test Measurement 80 8 Analysis of Latch Rupture Test 82 8.1 About this Chapter 82 8.2 Results and Physical Effects 83 8.2.1 Energy Flow Consideration 83 8.2.2 Pulse Consideration 86 8.2.3 Load and Velocity Consideration 86 8.2.4 Summary 91 9 Consolidation of the Two Crash Requirements 92 9.1 Integration of Frangible and Rigid Simulation Model 92 9.2 Linked Simulation Results 92 9.3 Dynamic Impact Loads on Safety Barrier Wall 93 9.4 Minimal Barrier Loads for Safety Barrier Wall Protection 96 9.5 Safety Barrier Wall Design Loads 99 10 Summary and Outlook 101