Anthropomorphic Test Device Neck Assembly with Segmented Vertebra Discs
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Solution Overview
Problem
Current anthropomorphic test devices (ATDs) or crash test dummies struggle to accurately replicate the biomechanical performance of a human neck in all directions, particularly in flexion, extension, lateral bending, and torsion, due to their design limitations which result in inadequate biofidelity during impact testing.
Innovation Solution
A neck assembly for ATDs is developed, comprising modular vertebra discs with ligament joints and a torsion element, allowing rotation to simulate human neck responses in flexion, extension, lateral bending, and torsion, with a tunable profile to reduce early bottoming out and evenly distribute loads, enhancing biofidelity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cylindrical neck design with grooves is used to control flexion and rear extension performance, then flexion and extension performance is improved, but lateral performance cannot be adjusted
Solution Approach 1:
The neck is divided into multiple vertebra discs (first, second, third vertebra discs) with distinct functions. The first vertebra disc has a non-circular cross-section for lateral bending control, while the second and third vertebra discs have circular cross-sections for flexion and extension control, allowing independent optimization of different motion directions
Solution Approach 2:
Different portions of the neck assembly have different structural properties tailored to specific motion directions. The first vertebra disc features an elliptical cross-section with major and minor axes to provide asymmetric stiffness for lateral bending, while other vertebrae use circular sections for symmetric flexion-extension behavior
2Reliability
If a neck with good lateral performance is used, then lateral bending performance is improved, but flexion and extension performance deteriorates and cannot be adjusted easily due to axial symmetrical mechanical design
Solution Approach 1:
The neck assembly is segmented into multiple functional units: a lateral bending mechanism with the first vertebra disc having non-circular cross-section, and a flexion-extension mechanism with the second and third vertebra discs having circular cross-sections, allowing independent adjustment of each motion type
Solution Approach 2:
The first vertebra disc employs an asymmetric elliptical cross-section to optimize lateral bending performance, while the second and third vertebra discs use symmetric circular cross-sections for flexion and extension, creating directional asymmetry in the overall neck structure to match human biomechanics
3Device complexity
If a neck assembly without torsion simulation is used, then structural simplicity is maintained, but ability to simulate human neck torsion response is lost
Solution Approach 1:
The torsion simulation is achieved by segmenting the neck into vertebra discs that can rotate relative to each other about the longitudinal axis, with the first vertebra disc providing torsion resistance through its non-circular cross-section geometry
Solution Approach 2:
The torsion response is controlled by changing the geometric parameters of the first vertebra disc's elliptical cross-section, where the ratio of major axis to minor axis determines the torsional stiffness characteristics to match human neck behavior
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The neck assembly provides superior biofidelity by accurately simulating human neck biomechanical performance in all directions, meeting biomechanical response requirements and reducing complexity for user-friendly operation.
Implementation Method 1
a torsion element coupled on one of the vertebra discs to allow rotation about an axis of the one of the vertebra discs to simulate torsion response of a human neck
Implementation Method 2
a plurality of ligament joints each having a joint element disposed between the vertebra discs
Data Source
AI summary
A neck assembly for an anthropomorphic test device (ATD) includes a plurality of vertebra discs, a plurality of ligament joints each having a joint element disposed between the vertebra discs, and a torsion assembly coupled to one of the vertebra discs to allow rotation about an axis of the one of the vertebra discs to simulate torsion response of a human neck.