Empyrical model of layered piezoactuators

Complex piezomaterials are frequently used in various mechanical systems. The piezomaterial, used in layered piezoactuators requiring high precision displacements, has indicated that accuracy depends on their design and technological factors.. The bifurcation problem of layered piezoactuator has been solved by evaluating physical properties of piezoelements and sealing material. That created posibility to prove that layered piezoactuators have a lot of possibilities of static operation. The original solution of layered piezoactuators enabled the choice of optimal initial stresses in piezostacks. Empyrical model of layered piezoactuators has revealed possibilities to optimize design of various mechanical system

Development of a finite element model of the sailplane fuselage

This paper presents development of finite element model of sailplane LAK-17B fuselage, which will be used to demonstrate the compliance with requirements of strength, deformation, crashworthiness and flutter behavior. FE analysis may be used only if the structure conforms to those for which experience has shown the method to be reliable. LAK-17B is a modification of a certified sailplane LAK-17A. Compliance with strength requirements of this sailplane was confirmed by load tests. Data of these tests will be used to evaluate numerical model reliability. The article presents modeling principles used to create finite element models of the sailplanes LAK-17A and LAK-17B together with consideration of load evaluation procedure

Optimization of the rocket’s nose and nozzle design parameters in respect to its aerodynamic characteristics

The airflow around rockets with various nose cone and nozzle cone geometric parameters is investigated in this paper. The mathematical background and the computational model of airflow around the rocket are designed for that purpose. ANSYS CFX computer modeling software is used to compute the airflow velocities, pressure, airflow turbulence kinetic energy, drag force and drag coefficient dependencies on rocket flight velocity. Optimization of the rocket’s nose cone and nozzle cone geometry in respect to qualitative and quantitative parameters of rocket’s aerodynamic characteristics is performed

Development and experimental analysis of layered actuators

Calculations indicate that a layered actuator composed of constituent elements tied together with binding material is a system characterized by high static strength. For this reason, these actuating systems are implemented in mechanisms that operate under heavy loads and require very precise displacements. Layered actuator used in mechanisms requiring high precision displacements have demonstrated that accuracy depends on design and technological factors. Analysis of different parameters of the actuator has enabled optimization of the structures and determination of their capabilities under varying mechanical load

Holographic interferometry methods for analysis & design of rotary converter

A rotary converter used in mechanisms that require high precision displacement has proved that accuracy depends both on design and technological factors. An important feature of mechatronic systems containing links made of active sandwich beam is the performance of various functions by the same transducer thereby enabling the development of improved design methods. The analysis of various parameters and constructions of mechatronic systems has made it possible to introduce the mechanism containing a rotary converter which can turn any top around or turn a screw. A holographic interferometry method has been applied in the experimental work [1, 2

Various Types of Piezomechanics Systems: Their Regimen and Experimental Analysis

The layered piezoactuators used in mechanisms requiring high precizion displacements have indicated that accuracy depends on design and technological factors. One of essential requirements for compound piezoactuators is their capability of transferring unipolar or bipolar force. In the first version, the piezoactuators acting in one direction is made of separate piezoelements and adapted binding materials. They operate under positive deformation (elongation due to neutral position) when the applied voltage is positive to polarity. The layered piezoactuators returns to its initial position under negative deformation (contraction) when the polarity voltage is applied opposite. The piezoactuators deformation in this direction only due to small forces of binding materials. When the piezoceramic is deformed by an external electric field, the input electrical energy is larger than the output mechanical energy. The ineffective electrical energy is stored as electrostatic energy in the piezostack and reverts to the power supply in the final process of an operating cycle. The efficiency is determined only by the loss such as hysteresis in the strain curve. The electromechanical feedback affects the correction of the hysteresis. It is evident that by applying the electromechanical feedback the hysteresis can be corrected up to 0.2% from the maximum displacement

The dynamics of the one-way pneumatic drive for training weapons

Riflemen’s trainers are efficiently applied for the training of the armed forces, police and shooting athletes. However, the training quality directly depends on the perfection of trainers as well as their functional facilities. Trainers should qualitatively develop the skills of correct levelling of a gun to target, represent probable combat situations and reproduce the process of single and shot series. The work presents the theoretical and experimental investigation of the pneumatic drive for recoil imitation of the weapo

Development of mortar simulator with shell-in-shell system – problem of internal ballistics

The shell-in-shell system used in the mortar simulator raises a number of non-standard technical and computational problems starting from the requirement to distribute the propelling blast energy between the warhead and the ballistic barrel, finishing with the requirement that the length of warhead’s flight path must be scaled to combat shell firing tables. The design problem of the simulator is split into two parts – the problem of external ballistics where the initial velocities of the warhead must be determined, and the problem of internal ballistics – where the design of the cartridge and the ballistic barrel must be performed. Initial velocities of the warhead determined in the problem of external ballistics form the set of initial data for the problem of internal ballistics of mortar simulator with shell-in-shell system. The ballistic barrel (reusable component of the mimicking shell) must be ejected from the mortar tube and its flight path must be only few meters. Moreover, the propelling charge can be located only in the warhead and the blast energy must be distributed between the warhead and the ballistic barrel. That turns the problem of internal ballistics into a complex nonlinear dynamical problem. Its solution involves building of the numerical model, optimisation of system parameters and experimental investigations. Presented mortar simulator proved its effectiveness in combat training exercises and is fully adopted in Lithuanian Army training facilitie

Design and research of a laser trainer with all the functions of the G – 36

Riflemen trainers are effectively applied for the training of armed forces, police and shooting athletes. However, the training quality directly depends on the perfection of trainers as well as their functional features. Trainers should qualitatively develop the skills of correct leveling of the G-36 to the target, represent probable combat situations and reproduce the process of single shots and shot series. This research work presents the theoretical and experimental investigation of the pneumatic drive for recoil imitation of the automatic gun G-36 and its employment in the laser riflemen trainers

3D holographic visualization of vibrations of cylindrical piezoceramic transducers

The piezoelectric material used in cylindrical transducers requiring high-precision displacements indicates that accuracy depends on design and technological factors. The analyzed criteria have enabled selection of piezoelectric material for optimal mechatronic systems having maximum displacement. Experimental investigation of precision dynamic systems by means of 3D holographic visualization enabled to collect appreciably more information about the vibrating surface in comparison with traditional methods. The developed methodology of analysis of experimental data derived from 3D holographic visualization using holographic measurement stand allowed to obtain results that are indispensable for optimization of design of mechatronic systems or its constituent elements