A new advancement in pedestrian safety:​ finite element (FE) modeling of the FLEX-PLI GTR

Shah, Chirag; Harn, Wen-Ren; Zhou, Hong; Kleessen, Christian; Zhu, Fuchun; Kant, Robert

Affiliations

¹Humanetics Innovative Solutions, Inc., USA

Abstract

The lower limb is one of the most frequently injured body regions in crashes involving pedestrians. A biofidelic FLEXible-Pedestrian Legform Impactor Global Technical Regulations (FLEX-PLI GTR) device has been developed with aim to advance global pedestrian safety regulations. It has been achieved under directions of the Flex-PLI Technical Evaluation Group (FLEX-PLI TEG). The FLEX-PLI GTR device is the latest development and successor of the earlier GT version.

The FLEX-PLI GTR device has major three regions: femur, knee and tibia. Central to the device are solid bone cores made of fiberglass representing tibia and femur bones. These bone cores have bending moment measuring capabilities at several locations along their axes. They are encased with segmental structures to achieve flexible human like bending behavior during pedestrian crashes. The outermost skin and flesh of the device consists of several rubber and neoprene foam layers. The knee region contains two knee blocks representing human like knee and has ligament elongations measuring capabilities to be used as injury criteria in regulations.

This paper documents the development and dynamic validations of the FLEX-PLI GTR FE models from its hardware counterpart. The models have been developed in four widely used FE codes that is LSDyna, Pam-Crash, Abaqus, and Radioss. The geometry and inertia properties of models are obtained from available drawings and hardware. The connectivity and structural integrity of models are established by experiments and verified against hardware. The material properties of models are implemented from material test data. These models are then validated against a variety of dynamic loading cases at component, assembly, and full legform levels. The femur and tibia bone bending moments and knee ligament elongations from the model output are compared to test data to evaluate model performance and injury predictability. A description of the model development is restricted to LS-Dyna FE code. However, model validation results are extended to include all four FE codes.

The FLEX-PLI GTR models revealed very promising performance in all validation cases and can be potentially used in future pedestrian safety regulations. The models were found to be very cost effective (in terms of CPU times) and reliable for pedestrian safety simulations.

Links

URL: http://www-nrd.nhtsa.dot.gov/pdf/esv/esv22/22ESV-000237.pdf

Cited Works (2)

Year	Entry
2005	Konosu A, Issiki T, Tanahashi M. Development of a biofidelic flexible pedestrian leg-form impactor (Flex-PLI 2004) and evaluation of its biofidelity at the component level and at the assembly level. In: Proceedings of the SAE World Congress & Exhibition. April 11-14, 2005; Detroit, MI. Warrendale, PA: Society of Automotive Engineers. SAE 2005-01-1879.
1998	EEVC Working Group 17 Report: Improved Test Methods to Evaluate Pedestrian Protection Afforded by Passenger Cars. European Enhanced Vehicle-Safety Committee (EEVC); 1998.