Research on a cascade model synthesis with the use of classical and non-classical methods in the context of new piezoelectric stack applications

Active audio noise cancellation technology using piezoelements is fairly new and emerging technology on the market in recent years and is still gaining in popularity. The ability to use piezoelectric devices to gather information about vibration spectrum and to create interfering waves, to cancel out the noise, allows for the reduction in passive vibration methods and gives more flexibility in terms of space and application. The idea of using this technique on larger scales such as industrial equipment is the focus of ongoing research conducted by the authors of this article. This work is intended as the first part of a larger project and focuses solely on theoretical approach to the problem of modelling mechatronic systems capable of creating complex vibration spectrums and using piezoelectric components. The authors have focused on creating a mix of classical and non-classical methods to synthesize model systems based on input resonance frequencies. A classical calculation through matrix equations was also done to validate the accuracy of obtained results through the structural number method. The resulting model is still awaiting the empirical verification through extensive testing on real-life models, and that part of the research is still being developed. When validated and checked, this technology could bring new solutions in the vibration damping of industrial equipment, potentially increasing its flexibility and effectiveness.

ASSESSMENT OF APPLES' DAMAGE IN CONTAINERS WHEN TRANSPORTING THEM ON ROADS WITH DIFFERENT SURFACES

Проблема и цель. Целью настоящего исследования является оценка влияния расположения в кузове автомобиля ящиков с яблоками сорта «Айдаред», устойчивыми к повреждениям, на изменение скорости колебаний отдельных плодов в декартовой системе координат при движении транспортного средства по дорогам с различным покрытием и с различной скоростью. Методология. В качестве объекта исследований были выбраны яблоки, уложенные в стандартный ящик, размещаемый в трех положениях в кузове автомобиля «Форд Транзит». Измерения проводились на дорогах с тремя различными типами покрытий – асфальт, щебень и грунт на скоростях автомобиля, находящихся в диапазоне 20-50 км/ч. При проведении исследований использован метод замера ускорений в трех направлениях встроенным в смартфон акселерометром с установленным на нем программным обеспечением «Измеритель вибрации 1.3.6 APK», а также классические расчетные методы, позволяющие определить скорость яблока и его кинетическую энергию. Результаты. Выявлено наилучшее (с точки зрения повреждаемости плодов) расположение ящиков с яблоками – между осями автомобиля, и наихудшее – над задней осью. Приведена оценка вероятных повреждений плодов на основе расчета изменения их кинетической энергии при движении автомобиля. Определено изменение влажности плодов во времени при имитации получасовой перевозки яблок по щебеночной дороге со скоростью 20 км/ч. Установлено, что зафиксированное повышение абсолютной влажности плодов (более, чем на 10 %) существенно ускорит процессы биологического разложения, и даже дополнительное охлаждение не сможет существенно замедлить этот процесс. Заключение. На основании проведенных исследований рекомендуется избегать дорог с грунтовым и щебеночным покрытием в период их неудовлетворительного состояния, а при невозможности избежать таких участков использовать низкую скорость движения (не выше 20 км/ч), располагая ящики между осями автомобиля. Problem and purpose. The purpose of this study is to assess the efect of the location of boxes with Idared apples, resistant to damage, in the car body on the change in the vibration speed of individual fruits in a Cartesian coordinate system when a vehicle moves on roads with diferent surfaces and at diferent speeds. Methodology. Apples in a standard box placed in three positions in the body of a “Ford Transit” car were chosen as the object of the research. The measurements were carried out on roads with three diferent types of surface – asphalt, crushed stone and soil at vehicle speeds of 20-50 km/h. During the research measuring accelerations was done with the help of an accelerometer built into a smartphone with "Vibration Meter 1.3.6 APK" software installed on it. Besides the classical calculation methods allowing to determine the speed of an apple and its kinetic energy were used. Results. The best (in terms of fruit damage) location of boxes with apples is found and that was between the axles of the car, and the worst ones were above the rear axle. The estimation of probable damage to fruits based on the calculation of changes in their kinetic energy when driving a car was given. The change of fruit moisture was determined when simulating a half-hour transportation of apples along a gravel road at a speed of 20 km/h. It was found that the recorded increase in the absolute humidity of fruits (more than 10%) signifcantly accelerated the processes of biological decomposition. And even additional cooling could not signifcantly slow down this process. Conclusions. Based on the conducted research it is recommended to avoid roads with dirt and crushed stone surfaces during their unsatisfactory condition. If it is impossible to avoid such sections a driver should use a low speed (no higher than 20 km/h) placing boxes between the axles of the car.

Wavefront Sensing for Evaluation of Extreme Ultraviolet Microscopy

Wavefront analysis is a fast and reliable technique for the alignment and characterization of optics in the visible, but also in the extreme ultraviolet (EUV) and X-ray regions. However, the technique poses a number of challenges when used for optical systems with numerical apertures (NA) > 0.1. A high-numerical-aperture Hartmann wavefront sensor was employed at the free electron laser FLASH for the characterization of a Schwarzschild objective. These are widely used in EUV to achieve very small foci, particularly for photolithography. For this purpose, Schwarzschild objectives require highly precise alignment. The phase measurements acquired with the wavefront sensor were analyzed employing two different methods, namely, the classical calculation of centroid positions and Fourier demodulation. Results from both approaches agree in terms of wavefront maps with negligible degree of discrepancy.

Calculation of prestressed structures for shock loading

Introduction. With the use of prestressing, coatings are made for special-purpose buildings, requiring calculations for extreme impacts. Such impacts include an airplane strike. Modeling of prestressed structures and calculation of shock loads is difficult to implement in classical calculation programs. A universal tool for solving such problems is the PC SOFiSTIK. This software complex allows you to interact with the most modern software solutions. Materials and methods. For the description of the method, special-purpose coating was selected and the strike calculation of the Learjet 23 aircraft was performed. For modeling prestressing, the SOFIPLUS interface is used. To describe the impact, the internal programming language CADINP is used. Results. The nature of the change in the coating deformations in the first seconds of the aircraft crash is presented graphically. Also, iso-ares of internal bending moments of the coating were derived for the selection of reinforcement and the diagram of the moments of the beams from the action of prestressing, taking into account tension losses. Conclusions. SOFiSTIK PC allows you to solve complex engineering problems with a high degree of automation. Thanks to the open source code, it becomes possible to calculate atypical extreme effects. The obtained graphs and diagrams confirm the passage of checks on the limiting states of the coating, and can also be used to design and calculate similar special-purpose structures.

An experimental study of the bearing capacity of wall models with openings under one and two-way loading

The results of an experimental and numerical studies of the stress-strain state of wall models under one and two way action are presented. The mechanisms of destruction of walls with openings are described. The functional dependencies between the destructive loads of the onset of crack formation and the influencing parameters are obtained. It is shown that the openings are stress concentrators, leading to the occurrence of micro and macro damage, the appearance and development of cracks, and in some cases to the loss of stability of structures (walls). The obtained influence functions can be included in traditional calculation methods with the aim of clarifying them. The factors affecting the process of cracking and fracture are given. Their modeling will allow to predict and prevent adverse events. Practical methods for regulating stresses, forces, and displacements that reduce the influence of various concentrators are considered. The analysis of the destruction mechanism of wall models carried out in this article allows one to study the influence of the size, position, and shape of window openings on the bearing capacity of walls. For example, the presence of stress concentrations in the region of the corners of square openings and their absence in round ones. The system of indicators of the sentry type ICh-10 made it possible to control the deformation of models from the plane of the walls, which is especially important under conditions of lateral pinching. The experimental values of the strength of the walls with openings compared with the calculated ones, which made it possible to see the degree of simplification of the classical calculation models used in design practice.

Justification of the parameters of a pneumatic conveyor for active ventilation of soybean during storage

The article proposes a methodology for studying the productivity (capacity) and power consumption of a pneumatic conveyor for active ventilation of soybeans in container-modular storage in farms and the factors affecting them. In determining the parameters of the pneumatic conveyor, the physical and technological characteristics of the grain (soybean) are taken into account. The proposed methodology is based on the method of classical calculation for selecting a pneumatic conveyor with nominal parameters, which is necessary not only for transportation, both vertically and horizontally, but also for active ventilation of grain in containers during storage. The purpose of the methodology is to select a specific pneumatic conveyor for container-modular equipment for soybeans storage in the conditions of farms in Kazakhstan.