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Thor-Lx Advanced Lower Extremity (Thor-LX/HIIIr)

Release to Public Domain

As a component of the Thor advanced crash test dummy development program, the National Transportation Biomechanics Research Center (NTBRC) of the NHTSA Research and Development Office has directed the development of an advanced lower extremity design, denoted as Thor-Lx, which incorporates improved biofidelic features and significantly expanded instrumentation. The Thor-Lx design incorporates new design approaches in the femur segment as well as in the tibia and foot /ankle segments.

The version of the mid-male Thor-Lx presently being released, denoted as Thor-Lx/ HIIIr, is intended for Hybrid III retrofit use, and mounts directly to the distal end of the Hybrid III femur. The Thor-Lx/ HIIIr assembly (see figures 1 and 2) is thus comprised of the Thor-Lx foot and ankle segments, the Thor-Lx tibia segment (with integrated Achilles assembly), the stock Hybrid III knee housing, a modified Hybrid III knee flesh, new molded side knee covers, and the stock Hybrid III ball bearing knee slider assembly.
Thor-LX assembly - no flesh
Figure1. Thor-Lx/HIIIr
Assembly (w/o flesh)		 Thor LX-HIIIr fully assembled
Figure2. Thor-Lx/HIIIr
Fully Assembled

Figures 3 and 4 illustrate the mechanical component and instrumentation layouts, respectively, of the Thor-Lx mid-male Hybrid III retrofit assembly.

image - 50th Percentile Thor LX Male HIIIr

Figure 3: Thor-Lx 50th Percentile Male Hybrid III Retrofit
Assembly - Mechanical Components

[Click on image to enlarge]


Instrumentation, 50th Percentile HIIIr

Figure 4: Thor-Lx 50th Percentile Male Hybrid III Retrofit
Assembly - Instrumentation

[Click on image to enlarge]


The Thor-Lx/ Hybrid III retrofit assembly includes the following new elements, as compared to the existing Hybrid III leg design:
    bullet Side mounted knee covers, which augment the existing narrow Hybrid III knee housing profile, to improve the realism of knee interaction with vehicle knee bolsters
    bullet A compliant tibia element, which modulates tibia response to axial impact to more realistically reflect human data
    bullet Provision for independent control of foot mobility about three axes of rotation (dorsiflexion/plantarflexion, inversion/eversion, and internal/external rotation), by means of progressive rubber elements whose characteristics are guided by human data
    bullet A representation of the Achilles tendon load path, which contributes to improved realism of tibia axial forces and bending moments
Instrumentation included as part of the Thor-Lx/ Hybrid III retrofit assembly includes:
    bullet Knee slider displacement
    bullet Upper tibia forces and moments (Fx, Fz, Mx, My)
    bullet Lower tibia forces and moments (Fx, Fy, Fz, Mx, My)
    bullet Tibia accelerations at mid-shaft (Ax, Ay)
    bullet Foot rotations about 3 axes
    bullet Mid- foot accelerations (3 axes)
    bullet Achilles tension (uniaxial, optional)

A detailed description of the design rationale and the process of development of Thor-Lx may be found in Reference 1.

NOTICE OF UPDATE TO VERSION 3.2

This version 3.2 release consists of the following downloadable components:

PLEASE NOTE:  The NHTSA has stipulated that all Thor-Lx/ Hybrid III retrofit hardware manufactured and delivered for use must conform to the specifications and certification performance requirements as defined within this release.  Further, the NHTSA has stipulated that all certification performance data must accompany newly manufactured and delivered Thor-Lx/ HIIIr hardware. 

Based upon the design concepts embodied in this release, development of a 5th percentile female version of the Thor-Lx/ Hybrid III retrofit design, denoted as Thor-FLx/ HIIIr, has also been completed.  The NHTSA has released full documentation for Thor-FLx/ HIIIr to the public domain at:

http://www-nrd.nhtsa.dot.gov/departments/nrd-51/thor_flx/ThorFLxweb.html

Two related NHTSA technical papers (Kuppa et al, 2001) may be of interest to users of Thor-LX and Thor-FLx hardware, and were presented at the 17th International Technical Conference on the Enhanced Safety of Vehicles, in Amsterdam, Holland:

For further information with regard to the Thor Lx/ Hybrid III Retrofit Version, Thor-Lx, or the Thor Advanced Frontal ATD please contact Mr. Mark Haffner, Thor Program Manager, NHTSA National Transportation Biomechanics Research Center, at (202) 366-4719 (phone) or by e-mail at mhaffner@nhtsa.dot.gov.

  1. T. Shams, D. Beach, R.P. White, N. Rangarajan, M. Haffner, R. Eppinger, H. Pritz, S. Kuppa, M. Beebe, "Development and Design of Thor-Lx: The Thor Lower Extremity," Proceedings of the 43nd STAPP Car Crash Conference, 1999, SAE Paper 99SC09