Browsing by Subject "Post-buckling"

Now showing 1 - 2 of 2

Open Access
An experimental approach to nanomechanical buckling and snap-through phenomenon
(2019-08) Hatipoğlu, Utku
Buckling has received little attention as a valuable resource for engineering applications since it is regarded as a type of failure in civil and mechanical engineering. Nevertheless, buckling has a great potential in nanoelectromechanical systems(NEMS) field as a bistable process that has rich and complex dynamics. Here, we explore post buckling dynamics of a nano-beam experimentally by employing various probing techniques. By employing an all-electronic architecture, we precisely control the buckling amount as well as buckling direction of the nano-beam which eventually gives us the ability to control a two-level mechanical system with high precision and speed. A full control over the potential energy landscape of the system is demonstrated with different techniques such as Scanning Electron Microscopy operated in three different modes and microwave coupling method. During proof of concept experiments, left and right buckling, large deflection buckling, nonvolatility – which is an indication of pure bistable states – and snap-through phenomenon is demonstrated. Further steps of the study focused on the snap-through phenomenon that is the interstate transitions of the buckling beam after bifurcation. During these experiments, more involved relations are investigated such as mechanical bias and effect of plastic deformation as well as the effect of actuation scheme on interstate jumps. Moreover, to obtain a better grasp of post-buckling dynamics, quantitative measurements are carried out which reveal the reaction speed of the system and time scale of interstate jumps. Lastly, oscillatory snap-through motion is observed in some special conditions that can be beneficial to understand noise dynamics of the system and it has a potential to contribute energy harvesting applications.
Open Access
Monitoring micromechanical buckling at high-speed for sensing and transducer applications
(IEEE, 2021-08-06) Demiralp, Berke; Pisheh, Hadi Sedaghat; Küçükoğlu, Berk; Hatipoğlu, Utku; Hanay, Mehmet Selim
Controlling the amount and direction of buckling at micro- and nano-scale efficiently opens up avenues for novel actuation and sensor applications. Earlier platforms that can achieve a full and non-thermal control of microscopic buckling operated only with a time resolution of 40 ms. Here, we have measured the buckling amount of a beam starting from unbuckled position and reaching to large post-buckling deformations by collecting secondary electrons under scanning electron microscope. Line mode is used for ultrafast measurements with 33kHz scan frequency, and a displacement noise floor of 40pm/√Hz was obtained. Moreover, by further reduction in the device dimensions, the buckling threshold voltage was reduced by a factor of three compared to similar platforms.