4.1This document provides guidance for functional simulation to evaluate durability of knee prosthetic devices under force control. 4.2By functional simulation, it is meant simulation that characterizes the variety of activity encountered throughout the activities of daily living. Functional simulation differs from wear testing in that it attempts to exercise the prosthetic device through a variety of loading and motion conditions such as might be encountered in situ in the human body in order to reveal various damage modes and damage mechanisms that might be encountered throughout the life of the prosthetic device. 4.3By force control, it is meant that mode of machine control, which accepts a force level as the set point input and which utilizes a force feedback signal in a control loop to achieve that set point input. For knee simulation, the flexion motion is placed under angular displacement control, internal and external rotation is placed under torque control, and axial load, anterior posterior shear and medial lateral shear are placed under force control. 4.4This document establishes kinetic and kinematic test conditions for several activities of daily living, including walking, turning navigational movements, stair climbing, stair descent, and squatting. The kinetic and kinematic test conditions are expressed as reference waveforms used to drive the relevant simulator machines actuators. These waveforms represent motion, as in the case of flexion extension, or kinetic signals representing the forces and moments resulting from body dynamics, gravitation and the active musculature acting across the knee. 4.5This document further establishes recommended combinations of activities necessary to characterize sedentary, active and athletic lifestyles. 4.6This document establishes recommendations for a soft tissue constraint model necessary to enable force control simulation throughout the range of motion and combination of motions expected for the several activities of daily living. 4.7This document does not address the assessment or measurement of damage modes, and wear and failure of the prosthetic device. 4.8This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
KeywordsReference frame system
The title and scope are in draft form and are under development within this ASTM Committee.Back to Top
Frederick Werner, MME, PE
Ballot Item Approved as F3141-2015 and Pending Publication