Ballistic Impact and Crashworthiness Response of Aerospace Structures

In designing the next generation of aerospace structures, particularly those using advanced materials, understanding their response under crash and ballistic impact conditions is of critical importance. The applications where these types of behaviors are important are diverse and include fan containment systems for aircraft engines, impact resistant aircraft fuselage structures, crash dynamics of rotorcraft structures, impact resistance of the Space Shuttle thermal protection system, and landing systems for the new Orion manned space capsule. To explore the state-of-the-art technologies in this subject area, a symposium on the “Ballistic Impact and Crashworthiness Analysis of Aerospace Structures” was held as part of the ASCE 2008 Earth and Space Conference, from March 3–5, 2008, in Long Beach, California. In this special issue, papers based on the presentations given at the symposium are presented. Specifically, papers related to practical applications of impact-resistant structures in the area of space vehicles, rotorcraft structures, and aircraft engine fan containment systems are presented. Furthermore, there are also papers on material model development, special applications of nonlinear finite-element methods, and algorithms devoted to dynamic and impact analyses. In the paper “Multiterrain Earth Landing Systems Applicable for Manned Space Capsules,” Fasanella presents a survey of landbased landing systems used in past space missions and aircraft fixed wing and rotorcraft including parachutes, airbags, and retro-rockets, to examine potential applicability to the new Orion manned space capsule. The paper describes new finite-element simulations of water landings of the Apollo command module conducted using the LS-DYNA code, which can be used to establish a benchmark for studies of the new Orion capsule. LS-DYNA simulations of land impact of the Orion capsule are then presented. For these new simulations, a proposed airbag landing system is used, and the soil properties expected to be present during a land impact are characterized. In the paper “Orion Crew Member Injury Predictions during Land and Water Landings” by Lawrence et al., the LS-DYNA transient dynamic finite-element code is used to simulate the probability of crew injury during the landing of the Orion space capsule under various conditions. The relationship of the new results to previous studies using the Brinkley model and specially designed dummies is discussed. The applicability of this work to providing guidance for seat and helmet improvements for the Orion capsule designed to reduce injury to the astronauts is described. In the paper “Shuttle Debris Impact Analysis: Post return to Flight Real-Time Mission Support,” Firko et al. provide an overview of the assessment of debris impact on the Space Shuttle through the use of LS-DYNA finite-element simulations that took place during several recent missions. The general mission support role in the analysis of the severity of debris impact events is described. Specifically, analyses of the potential damage from insulation blankets coming loose and impacting different parts of the Shuttle during several recent missions is discussed. The finiteelement simulations served to quantify the risks to the vehicle from potential debris impacts. In the paper “Overview of the National Aeronautics and Space Administration Subsonic Rotary Wing Aeronautics Research Program in Rotorcraft Crashworthiness” by Jackson, Fuchs, and Kellas, an overview of the rotorcraft crashworthiness research being conducted at NASA Langley Research Center is presented. The development and testing of a new Kevlar composite deployable energy absorber designed to absorb crush loads is discussed. An overall description of the test program and finite-element simulations being performed with the goal of determining occupant injury during rotorcraft impact events into a variety of land and water surfaces is presented. A probabilistic analysis of the energy absorber concept is also described. In the paper “Ballistic Impact Response of Kevlar 49 and Zylon under Conditions Representing Jet Engine Fan Contain