Relax to stress
The use of stress relaxation to make an initially zero-stiffness mechanisms neutrally stable
M. Blaakman (TU Delft - Mechanical Engineering)
Giuseppe Radaelli – Mentor (TU Delft - Mechatronic Systems Design)
More Info
expand_more
Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.
Abstract
The creation of neutrally stable compliant mechanisms is a balancing act between knowledge on the system and the application of a stiffness countering prestress. This paper presents a novel prestressing method for polymeric compliant zero-stiffness mechanisms, utilizing stress relaxation as an actor for imprinting a permanent elevated internal stress state. The method in questiondoes not require a complex mechanical setup for application of the prestress. A sensitivity analysis is performed for the variables of relaxation time and imposed deformation. Two mechanisms with different origins for zero-stiffness behaviour are presented, and made neutrally stable. The simulations for one of the two examples, after correcting for a stretch in the force-displacement relation ship, match with the experimental results for both the variation in relaxation time and imposed deformation. For the second mechanism, the simulation for relaxation time matches that of the experiment, but for theimposed displacement this does not seem to be the case.