We studied consecutive impact loading on woven high-modulus polyethylene
rope, which is used in robotics fields. An impact tester was developed to conduct
the experiments. Five consecutive impact loads (five drops) were applied
to the rope and the stiffness of the loading part that corresponds to each drop
was evaluated. The stiffness of the woven ropes was affected strongly by consecutive
impact loading. The change in stiffness is undesirable in some applications
such as in robotic fields. Therefore, we have proposed a method that
can optimize changes in stiffness by applying a preload before impact testing
(preload treatment). The experimental results show that preload is an efficient
way to reduce changing rope stiffness. We have also proposed an empirical
equation that can estimate the rope stiffness after arbitrary preload treatment,
and this equation is a function of the number of drops and the static preload
level. The equation can be used to determine the preload treatment conditions
to stabilize the stiffness of the woven ropes before they are used in engineering
fields