Vibroacoustic handling and levitation of microparticles in air

The levitation and controlled movement of substances in the air has many potential applications, from materials handling to biochemistry and pharmacy. In this work, the handling of microparticles by sound field in vibrating cylinder was investigated by simulation and experimental measurement. A standing wave field created between the piezotransducer and the reflector created the conditions for levitating microparticles, which were concentrated at nodes of the vibrating cylinder surface. The acoustic wave and the cylinder walls were excited by the same disk-shaped piezotransducer fixed to the bottom of the cylinde

Finite element analysis of polymer-encapsulated ZnO nanowire-based sensor array intended for pressure sensing in biometric applications

This work presents results of finite element analysis of an array of ZnO nanowires with bottom-bottom electrode configuration, which are integrated onto a multi-layer chip stack and encapsulated within a polymer. The dynamically-deformed array constitutes a representative part of a high-resolution pressure sensor intended for reliable identification of the smallest fingerprint features such as shape of the ridges and pores. Parametric study was performed in order to predict the most rational values of the Young's modulus and thickness of the encapsulation layer in terms of magnitude and variability of the piezoelectric signals. The results also demonstrate the impact of nanowire aspect ratio and load orientation on the generated electrical signals

Numerical Analysis of Dynamic Effects of a Nonlinear Vibro-Impact Process for Enhancing the Reliability of Contact-Type MEMS Devices

This paper reports on numerical modeling and simulation of a generalized contact-type MEMS device having large potential in various micro-sensor/actuator applications, which are currently limited because of detrimental effects of the contact bounce phenomenon that is still not fully explained and requires comprehensive treatment. The proposed 2-D finite element model encompasses cantilever microstructures operating in a vacuum and impacting on a viscoelastic support. The presented numerical analysis focuses on the first three flexural vibration modes and their influence on dynamic characteristics. Simulation results demonstrate the possibility to use higher modes and their particular points for enhancing MEMS performance and reliability through reduction of vibro-impact process duration

Ultrastructure of a Mechanoreceptor of the Trichoid Sensilla of the Insect <i>Nabis rugosus</i>: Stimulus-Transmitting and Bio-Sensory Architecture

This paper presents the ultrastructure morphology of Nabis rugosus trichoid sensilla using SEM and TEM data, along with a two-dimensional model of the trichoid sensilla developed in Amira software. The SEM images show the shape and scattering of the trichoid mechanosensilla over the N. rugosus flagellomere. The TEM images present the ultrastructural components, in which the hair rises from the socket via the joint membrane. The dendrite sheath is connected at the base of the hair shaft, surrounded by the lymph space and the socket septum. This dendrite sheath contains a tubular body with microtubules separated by the membrane (M) and granules (Gs). This study presents a model and simulation of the trichoid sensilla sensing mechanism, in which the hair deflects due to the application of external loading above it and presses the dendrite sheath attached to the hair base. The dendrite sheath is displaced by the applied force, transforming the transversal loading into a longitudinal deformation of the microtubules. Due to this longitudinal deformation, electric potential develops in the microtubule’s core, and information is delivered to the brain through the axon. The sensilla’s pivot point or point of rotation is presented, along with the relationship between the hair shaft length, the pivot point, and the electric potential distribution in the microtubules. This study’s results can be used to develop ultra-sensitive, bioinspired sensors based on these ultrastructural components and their biomechanical studies

Simulations of the working contact loads of a tillage element

It has been suggested that the wear characteristics of a cultivator tip during tillage and a finite-element model based on the combination of the Euler and Lagrange methods be studied. The results of simulations show that surfaces with the largest contact loads correspond to the surfaces with greatest wear. It has been noted that the lower point of the front edge at a cultivator tip is under the action of the greatest contact load (120 N)Kauno technologijos universitetasVytauto Didžiojo universitetasŽemės ūkio akademij

Estimating Stresses and Movement Work of a Soil-Cultivator Tip Using the Finite-Element Method

Original Russian Text R. Skirkus, V. Jankauskas, R. Gaidys, 2016, published in Trenie i Iznos, 2016, Vol. 37, No. 5, p. 630–635Working parts of tillage machines are in direct contact with soil abrasives. The shape and dimensions of the working parts undergo changes due to friction and wear. A finite-element model has been created for studying the stresses and in-soil movement work of the designed cultivator tip. The problem has been solved with a coupled Eulerian–Lagrangian method (the SIMULIA ABAQUS software). It has been shown that the minimum in-soil movement work of 3400 J is done by a tip with a sharpening angle of 185°Kauno technologijos universitetasVytauto Didžiojo universitetasŽemės ūkio akademij

Dynamics of the Missile Launch from the Very Short-Range Mobile Firing Unit

In this article, the results of research of dynamical processes during the first stage of a missile launch from very short-range mobile firing unit (MFU) are presented. The determined laws of motion of the system’s components enabled determining characteristic motions that need to be reconstructed by the launcher simulator intended to be developed for personnel training. The half-car approach is applied for modelling the unit which consists of a vehicle and is attached to its missile launcher. The combined system is represented by a lumped-parameter model. The mathematical model is derived by applying the principle of Lagrange differential equations. Motion laws of the components of the system as its response to excitation load generated during missile launch were determined

Shape optimization of the active element for vibration energy harvesting

As the use of renewable energy is increasing exponentially all around the world, the micro energy sources are no different. One of renewable micro energy generator is transducer which can make electricity from the relative displacement present within the system or the mechanical strain. A technique was created to maximize the collection of the electricity generated from a piezoelectric fiber, based on modes of transversal vibration. Created the numerical and computational models of the dynamic element's shape advancement issue. Normal strain top generation was expanded by 49%. The energy rise was 16%. The exploratory stands and strategies were created for the test confirmation of the depicted numerical modeling results. Comes about gotten from the try utilizing the holography method were compared to hypothetically gotten eigen frequencies and mode shapes, and the mistake does not surpass 3%