Walter D. Pilkey

LIMITING PERFORMANCE OF SEAT BELT SYSTEMS FOR THE PREVENTION OF THORACIC INJURIES

Abstract The theoretically optimal performance of seat belt systems for occupants in automobile frontal crashes is investigated based on a two-mass injury model of the thorax. The performance is measured by thoracic injury criteria which include the maximum chest acceleration, compression and viscous response. The relationship between the best possible performance (limiting performance) of the seat belt system and the distance between the occupant and the interior components of the vehicle is displayed in the form of trade-off curves, which can be used for the evaluation of seat belt performance. The characteristics of the optimal seat belt force and the kinematics of the system are illustrated. The results indicate that the optimal seat belt force is not constant during an impact and that an initial impulse is required. However, constant seat belt force can provide thoracic restraint that is close to the optimal solution.

Shock and Vibration Computer Programs, Reviews and Summaries

Contents: Computer Programs--Multiple Energy Domain Systems, Transfer Function Analysis, Dynamics of Spacecraft Structures, Torsional Systems, Crash Simulation, Highway Vehicle Simulation, Cable Systems, Offshore Structures Analysis, Frames, Nonlinear Transient Response of Solids, Time Dependent Materials, Prediction of Highway Noise, Liquid Propellant Dynamics Analysis, Optimum Design of Dynamic Mechanical Systems, Mechanical and Thermal Shock Analysis, Random Vibration of Structures, Beams, Piping Systems, Dynamic Buckling of Structures, Limiting Performance of Structural Systems, Grillages, Kinematic and Dynamic Design of Mechanism, Seismic Analysis, Simulation of Human Body Response to Crash Loads, Test Data Reduction and Processing, Fluid Structure Interaction, Rotating Machinery, Aircraft Noise Prediction, and Shell Analysis; Capabilities and Routines within Programs--Summary of General Purpose Programs, Nonlinear Analysis Descriptions and Numerical Stability, Fracture and Fragmentation Under Shock Loading, Eigenvalue Extraction, Damping, and Inertia Matrices for Finite Elements; and Indexes--Subject Index of Shock and Vibration Computer Programs, and Alphabetical Index of Shock and Vibration Computer Programs.

Some properties and applications of singularity functions based on the theory of distributions

Abstract Some properties of singularity functions useful for applications to the mechanics of deformable solids are developed with Schwartzs Theory of Distributions and applied to beam and plate flexure problems. In the development of the mathematics of singularity functions, which are postulated to be the kernels of distributions, it is shown that for these properties no discrepancy occurs when the singularity functions are considered as ordinary point functions.

Limiting performance analysis of toepan padding for mitigating lower limb injuries

Abstract The potential application of using toepan padding for the prevention and reduction of lower limb injuries is investigated computationally in this paper. A two-mass lower limb injury model is developed on the basis of impact tests using post-mortem human surrogates. A limiting performance analysis is used to find the best possible physical performance and characteristics of passive and active padding for the minimization of peak tibia force. Computational results indicate that, for the prevention and reduction of lower limb injuries, the active padding is superior to the passive padding.

Dynamic response of the Hybrid III three year old dummy head and neck during side air bag loading

Abstract This paper presents the results from 14 tests designed to evaluate the response and injury potential of a Hybrid III three year old dummy subject to loading by a deploying seat mounted side air bag. An instrumented Hybrid III three year old dummy was used for tests in two different occupant positions chosen to maximize head and neck loading. Four seat mounted thoracic side air bags were used that varied only in the level of inflator output. The National Highway Traffic Safety Administrations neck injury criteria for complex loading were modified to include moment values for both anterioposterior and lateral directions. The results indicate that side air bags may be designed so that the forces and moments in the child dummys neck are below injury threshold values during a side air bag deployment. While there is considerable uncertainty as to the validity of published injury criteria owing to the lack of child biomechanical data, this study demonstrates the sensitivity of child response to initial position which provides insight into placement and geometry of side airbag systems. Furthermore, the data indicate a relationship between airbag inflator properties and child dummy response for a given airbag geometry.

Fifth percentile female dummy upper extremity interaction with a deploying side air bag

Abstract This paper presents the results from experiments designed to characterize the upper extremity response of the small female during side air bag loading. A seat-mounted thoracic side air bag was deployed statically using three different inflators. The aggressivity of the inflators varied in peak pressure and pressure onset rate. The fifth percentile female HIII dummy was utilized in three positions, which were chosen to maximize loading of the humerus and elbow joint. Two had the dummy positioned outboard with the forearm on the armrest, and the third had the dummy inboard such that the humerus was positioned horizontally in front of the air bag module with the forearm supported above the armrest. Instrumentation for the fifth percentile female dummy included the fully instrumented SAE upper extremity with six axis load cells in the humerus and forearm as well as accelerometers and angular rate sensors attached to each segment. All inflators produced resultant humerus moments below published injury tolerance values for the small female, with the more aggressive air bags producing higher responses. The upper extremity proved useful in evaluating injury risk relative to side air bag design.