6.5 Hybrid III Anthropomorphic Model
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6.5 Hybrid III Anthropomorphic Model

  6.5.1 Anthropomorphic models are mechanical surrogates of the human body that can be used to assess the potential for human injury of prescribed impact and/or acceleration environments. Such human surrogates are designed to mimic pertinent human physical characteristics so that their mechanical responses simulate human responses. The time-histories of these mechanical responses are analyzed to estimate the potential for various types and severity of injuries to humans. The results of these analyses are based upon the assumption that the anthropomorphic model and the human are exposed to the same impact or acceleration environment (Mertz, 1985).

  6.5.2 The Hybrid III is a 50th percentile adult male frontal impact dummy developed by General Motors in 1976. It is based on the ATD 502 dummy which is an advanced test dummy developed by General Motors in 1973 under a contract with the National Highway Traffic Safety Administration. The ATD 502 featured a head which had human like response characteristics for hard surface forehead impacts, a curved lumbar spine to achieve human like automotive seating posture, and a shoulder structure designed to improve the belt-to-shoulder interface which was a problem with the Hybrid II (Mertz, 1985). The Hybrid III maintained the head, lumbar spine and shoulder of the ATD 502. Design changes were made in the Hybrid III to improve the impact response biofidelity of the neck, chest, and knees. The biofidelity characteristics of the Hybrid III dummy are presented in Table 6.4.

Table 6.4 Biofidelity Characteristics of the Hybrid III Anthropomorphic Model (Mertz, 1985)

Body Part Biofidelity Attributes Biofidelity Deficiencies
Head Exterior size and shape of 50th percentile adult male. Human like head-to-neck attachment location. Human like mass and sagittal plane mass moment of inertia. Human like response for deforming surface impacts. Human like response for hard surface forehead impacts. Mass moment of inertia may not be human like for other than the sagittal plane. Hard surface impact response may not be human like for side top and rear of head.
Neck Human like fore/aft bending response. Lateral bending response may not be human like. May be too stiff in axial compression.
Thorax Exterior size and shape of 50th percentile adult male. Human like mass. Human like impact response for fore/aft compression due to distributed sternal impacts. Rib age geometry not human like. Mass distribution not human like. Lateral impact response not human like. Concentrated load impact response not human like.
Lumbar Provides human like sitting posture. Bending response not human like.
Pelvis Human like pelvis shape. Mass and mass distribution not human like.
Legs Human like ranges of motion. Human like knee response. Mass distribution not human like. Joint resistances not human like.
Arm Human like range of motion. Mass distribution not human like. Joint resistance not human like.
Shoulder None Mass distribution not human like. Load-deflection responses not human like.

  6.5.3 Accelerometers were incorporated into the Hybrid III to measure the orthogonal linear components of acceleration in the head and chest. Force transducers were incorporated to measure the forces and bending moments between the head and the neck at the occipital condyles (Mertz, 1985). Transducers were also incorporated to measure displacement of the sternum relative to the thoracic spine and axial femoral loads. Presented in Table 6.5 are the injury-predictive capabilities possible with the Hybrid III.

Table 6.5 Injury-Predictive Capability of the Hydbrid III Anthropomorphic Model Head, Thorax, Neck, and Lumbar (Mertz, 1985)

Body Part Injury-Predictive Capability
Head Brain injury and/or skull fracture predictions based on linear acceleration measurements possible for deforming surface impacts to front, top, back, and side of head and for hard surface impacts to forehead Brain injury prediction due to sagittal plane rotational effects possible
Neck Measured neck loads provide a basis for predicting neck injuries
Thorax Thoracic injuries related to gross thoracic acceleration, sternal acceleration, and gross fore/aft thoracic compression
Lumbar None
Parent topic: Section 6 – Human Tolerance To Acceleration Forces
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