Mounting Surface Research Articles

Interference joint of enhanced bearing capacity

State of the art technology implies the application of increasing power at high speeds, therefore various interference joints strength enhancing is an urgent task. On the basis of the review of the existing interference joints bearing capacity improving research methods, the approach being implemented by the joint internal member mounting surface modification with the help of grooves of shallow depth is proposed. The experimental results of the modification various parameters influence on the fit bearing capacity are presented. It is reasonable to use the given engineering solution for fit strength restoring when performing the repair work.

A Fast Bolt-Loosening Detection Method of Running Train’s Key Components Based on Binocular Vision

Bolt-loosening can cause poor running quality of trains, even resulting in terrible accidents. Currently, existing bolt-loosening detection methods for running trains need 3D data of the whole train body, extremely decreasing the efficiency of fault detection. In this paper, we propose a fast bolt-loosening detection method for the running train's key components based on binocular vision. Since a train generally consists of many cars with the same structure, the position distribution of train's key components is regular and periodic. First, we propose a novel method to detect key component regions including bolts, taking full advantage of this periodic distribution rule. Second, the sub-pixel edges of the bolt cap and mounting surface in the localized regions are extracted and segmented, respectively, combining with the convolutional neural network (CNN). Finally, based on stereo matching and the binocular vision model, the 3D data of these edges are obtained to calculate the distance between the bolt cap and mounting surface. By comparing the calculated distance with the reference value, we can judge whether bolt-loosening has occurred. The experimental results indicate that multi-bolt looseness can be calculated simultaneously. The measurement repeatability and precision are superior to 0.03 and 0.08 mm, respectively, and the relative error is less than 1.42%.

A Novel Method for Reconstructing Flatness Error Contour of Long Surface Based on a Laser Displacement Sensor

In order to solve the problem that the flatness error contour curve of the guideway mounting surface on machine tools can not be intuitive description, a novel method is proposed in this paper. The principle is to divide the measured surface with a certain length into several short surfaces with overlapping region, and the segmented surfaces are measured respectively, then the flatness error contours of the segmented surfaces can be obtained, finally, the segmented flatness error contours are spliced together to reconstruct the flatness error contour of the entire surface. On this basis, the detection instrument is designed, the detection principle is given, the benchmark plate is customized to identify the starting position and ending position of measurement, the reference surface and the measured surface are measured respectively in combination with the detection instrument and the benchmark plate. Then, an algorithm is developed to convert the distance difference between the reference surface and the measured surface into the flatness error contours of segmented surfaces. Next, using the geometric relationship between overlapping region of segmented flatness error contours, an algorithm is studied which can splice these segmented flatness error contours and reconstruct the flatness error contour of the entire surface. Meanwhile, mathematical models of the algorithms are established, and the measurement experiment is carried out. The results demonstrate that this method can reconstruct the flatness error contour of long surface accurately.

CFD-моделювання температурного поля корпуса-радіатора передавального модуля АФАР з повітряним охолодженням

Modern radar stations are widely used to obtain images of earth surface with high spatial resolution, to identify moving objects in the air, on sea and on the ground, and allow determining the coordinates and movement parameters accurately. Active phased antenna arrays with large number of transmitting modules are widely used as antenna systems in radar stations. The heat generated by the active microwave elements of the output amplifiers of the transmitting module, leads to an increase in their temperature and to decrease in reliability. In this regard, the task of increasing the cooling efficiency of active microwave elements of the output power amplifiers is important. The aim of this study is to assess the possibilities of air cooling of the active elements of the output power amplifier in relation to the transition from gallium arsenide to gallium nitride element base with increased heat generation. This paper presents the results of computer simulation for the temperature filed of the mounting base of the radiator casing, on which 8 heat-generating elements with a local heat release of 28 W each are installed. Cooling fins are made on the opposite base of the radiator casing. The finned surface of the radiator casing is blown by an air stream with an inlet air temperature of 40°C. The simulation was carried out for three values of the air flow rate in the interfin channels: 1, 6 and 10 m/s. It is shown that the maximum temperature of the mounting base of the radiator casing is 90.1°C and is observed at an air flow rate of 1 m/s inside the interfin channels. Increasing the air speed up to 10 m/s makes it possible to reduce the temperature at the installation site of the microwave elements down to 72.1°C. A new technical solution was proposed to further improve the efficiency of the applied cooling system and to reduce the temperature of the mounting surface of the radiator casing.

Cascaded on-chip phonon shield for membrane microresonators.

We propose to suppress acoustic wave coupling between a Si3N4 membrane resonator and its support structure through cascaded low-frequency resonators fabricated on the silicon substrate of the membrane. The on-chip silicon resonators are designed to ensure that the frequencies of their oscillatory motion are well separated from the mechanical modes of the membrane resonator. Using optical interferometry, we characterize the displacement response of the membrane frame with the vibration isolation; mechanical isolation >30 dB from the mounting surface is achieved. Thus, we reliably fabricate Si3N4 membrane resonators with mechanical quality factors of around 2×106 at room temperature.

P218] Effect of flattening filter mounting surface position in Monte Carlo model of linear accelerators

Purpose Monte Carlo (MC) is considered as the gold standard for dose calculations of complex radiotherapy and the accuracy is mainly restricted by the statistical uncertainty. However, accurate MC simulations of radiation transport rely on a detailed description of the linear accelerator. The linac head is modelled in the specific MC code by using a geometrical description provided by the vendor. Interpreting the vendor provided drawings is, however, sometimes subject to uncertainties and vendors are not always willing to answer detail oriented questions. The position of the flattening filter (FF) mounting surface could be one such example. This study aimed at investigating the potential impact of an error in modelling the linac FF mounting surface. Methods Vendor-provided drawings of a modern linac head were interpreted and the 6 MV FF mounting surface was determined to have three possible positions. The positional uncertainty was in the distance from the linac target at which the mounting surface was placed. Discussions with the vendor and local engineers revealed one main candidate to be the correct choice, but nevertheless with doubt. The linac was therefore modelled in the BEAMnrc/EGSnrc user code with the three different geometries. Simulations of the radiation transport through the entire upper static part of the linac head were conducted and beam specific parameters were extracted and compared at a distance of 80 cm from the target. Results Interpreting the vendor provided drawings in three different ways revealed a maximum difference in the 6 MV FF mounting surface position of 1.6 mm from the most likely option. Analysis of the beam energy fluence (function of energy and off-axis position) at 80 cm distance from target revealed small differences (⩽1%). The beam was therefore considered to be independent of the mounting surface position within the distance variations investigated. Conclusions This study demonstrates that MC simulations are only marginally effected by various interpretations of the linac FF mounting surface position if positional differences are as low as 1.6 mm. Nonetheless, thorough and critical study of vendor provided drawings is necessary in order to conduct accurate MC simulations for radiotherapy purposes.

AUTONOMOUS HEAT SUPPORT SYSTEM OF ELECTRONIC BLOCKS OF SPACE APPLIANCES

The vast majority of electronic devices on-Board Russian spacecraft is placed on a temperature-controlled mounting surface is ON, however, in some tasks there is a necessity to place a separate electronic units out thermostated panels on remote spacecraft design. The article presents an autonomous system of providing thermal regime of electronic blocks of spacecraft and objects of space technology that require maintaining the operating temperature and are unable to be installed on the thermostatic landing surfaces of spacecraft. The proposed autonomous system of providing thermal regime can operate autonomously in the extended operating temperature range of the installation surface from -80 to +80 °C when the supply voltage changes in the range from 75 to 550% of the nominal value. The review of the existing solutions is presented, the substantiation of the proposed decision is given, the structural scheme of autonomous system of providing thermal regime is given and its description and an example of application is given.

Reduction of Kinematic Resistance To Movement Of the Railway Vehicles

The aim of the work is to reduce the train rolling resistance to movement the railway vehicles. The article proves the expediency of changing the constructive scheme of railway vehicle wheel, which allows independent rotation their wheel mounting surface rolling and the guide surface (flange). There has been carried out the classification and analysis of the advantages and disadvantages of various structural schemes wheels of the railway vehicles. There has been analyzed the Features resistance to movement wheels of traditional and perspective constructive scheme. The obtained results allow drawing a conclusion about the possibility of a significant reduction in train rolling resistance to movement of railway vehicles with wheels perspective constructive scheme.

Classification and Applicability of Technological Mandrels

В данной статье рассмотрен вопрос разнообразия технологических оправок, применяемых на операциях механической обработки в цехах промышленных предприятий. Для условий современного производства была представлена классификация технологических оправок по их технологическим признакам, которая раскрывает тип оправок в зависимости от вида установочной поверхности, вида базовой поверхности и типа посадки обрабатываемой детали с установочной поверхностью оправки. Далее в статье приведена логическая таблица выбора оправок в зависимости от параметров применяемости: вид обработки, точность базового отверстия обрабатываемой детали, соотношение длины к диаметру, радиальное и торцевое биение заготовки и вид применяемой оправки. Затем представлен подход создания информационно-поисковой базы данных технологических оправок на основе применения булевых функций. Использование такой базы данных на промышленных предприятиях позволит подбирать тип необходимой технологической оправки на основе синтеза производственных параметров. Так, в статье представлены булевы функции шлицевой оправки с жидким наполнителем и переналаживаемой оправки с полиуретаном, используемые на операции токарной обработки. В завершение представлены булевы функции основных конструкций технологических оправок, выведенные на основе логической таблицы.

Specificities of choosing of tolerances of the rolling bearings and of the parameters of geometry precision of the shaft and housing surfaces

The standards and methods concerning assignment of rolling bearing fit with shafts and frames via example of bearing 6-208 are analyzed. We set certain differences of recommendations according to GOST 3325-85, Rolling bearings. Tolerance zones and technical requirements to mounting surfaces of shafts and frames. Attachment and by reference of rolling bearing manufacturers. The following factors should be taken into consideration when assigning the mounting with the tension the internal ring of the bearing with shaft and mounting with a gap in the outer ring with a housing bore. The methods of achieving accuracy of mounting surfaces of shafts and frames via form tolerance assignment: roundness tolerance, profile of longitudinal cut, cross section, cylindricity and others. It is possible to limit the bearing rings in different ways, for example appointing the cylindrical mounting surfaces and bead end surfaces the appropriate tolerances, namely: coaxiality tolerance or full radial beat of mounting surfaces, and also perpendicularity tolerance, butt beats and full butt beats of mounting end surfaces. We suggest to expand methods of achieving the accuracy of shafts and frames depending on seriation of production and production operations metrology support.

Evaluation of measurement error in rotational mounting of larval Rhipicephalus (Acari: Ixodida: Ixodidae) species in geometric morphometrics

Geometric morphometric analysis, in combination with modern computational power, allows for precise measurements of morphological shape to study even minimal variation. One key challenge, however, is 2D photographs which serve as proxies for 3D structures that introduce measurement error into a dataset by omitting variability in the Z dimension. The ease of application of 2D proxies means we should optimize them, rather than limit studies by enforcing expensive or complex protocols. This may be done by explicitly measuring and reporting error. A rotational mounting surface should be capable of reducing measurement error associated with positioning (rotation). This study empirically quantified positioning error in basis capituli of three closely related Rhipicephalus species larvae. It investigates symmetrical and asymmetrical components of variation, in addition to the number of replicates required to obtain confident results. Asymmetry showed rotational error along the roll axis (side to side) which had a large effect that confounded species variation. In contrast, symmetrical variation showed much less rotational error, and only along a pitch axis (forwards and backwards) that was much smaller than species variation. Some systematic error was noted in roll axis variation that caused the left sides of specimens to be slightly raised. However, this error was small, and was avoidable when considering symmetrical variation. Confidence of differences in multivariate means between groups increased drastically with three replicates (15%), and slightly more with five (5%). This study demonstrates that variation at and below the individual level is out of scope for rotational mounting, and will provide unreliable results. However, this mounting method is validated for questions pertaining to species variation and taxonomy.

Laser Capture Microdissection Protocol for Xylem Tissues of Woody Plants

Laser capture microdissection (LCM) enables precise dissection and collection of individual cell types from complex tissues. When applied to plant cells, and especially to woody tissues, LCM requires extensive optimization to overcome such factors as rigid cell walls, large central vacuoles, intercellular spaces, and technical issues with thickness and flatness of the sections. Here we present an optimized protocol for the laser-assisted microdissection of developing xylem from mature trees: a gymnosperm (Norway spruce, Picea abies) and an angiosperm (aspen, Populus tremula) tree. Different cell types of spruce and aspen wood (i.e., ray cells, tracheary elements, and fibers) were successfully microdissected from tangential, cross and radial cryosections of the current year’s growth ring. Two approaches were applied to achieve satisfactory flatness and anatomical integrity of the spruce and aspen specimens. The commonly used membrane slides were ineffective as a mounting surface for the wood cryosections. Instead, in the present protocol we use glass slides, and introduce a glass slide sandwich assembly for the preparation of aspen sections. To ascertain that not only the anatomical integrity of the plant tissue, but also the molecular features were not compromised during the whole LCM procedure, good quality total RNA could be extracted from the microdissected cells. This showed the efficiency of the protocol and established that our methodology can be integrated in transcriptome analyses to elucidate cell-specific molecular events regulating wood formation in trees.

Экспериментальные исследования спектров шума процесса шарико-стержневого упрочнения узлов колесных пар

Introduction. Currently, wheel tread surfacing is implemented on special design wheel lathes. This method provides the desired technological strength of the wheel treads, but does not provide hard facing and, consequently, does not increase wear resistance. Ball-rod hardening (BRH) has great advantages as a process, especially for composite geometric surfaces; and besides, it enables the necessary compressive stresses in the surface of the hardenable products. However, it has a significant disadvantage in terms of the increased levels of the acoustic pressure in the operators’ working area. Materials and Methods . The experimental studies under BRH of the wheelpair assembly elements are carried out by several process steps. Wheel tread surfacing is performed on a special design wheel lathe on which ball-rod reinforcers are installed instead of a cutter. Hardening of the mounting surfaces of the wheelset axles is performed on a special axial lathe on which, in a similar manner, ball-rod reinforcers are installed instead of a cutter. Hardening of the wheel mounting surface is performed on a boring-and-turning mill. The octave sound pressure levels are measured on all of these lathes at idle and under the hardening process implementation. It allows determining the contribution of the sound radiation of the acoustic subsystem “hardenable product - ball-rod reinforcer” into the soundfield generated by a common lathe loudspeaker system in the operators’ working area. Research Results . Due to the high intensity of the radiant sound energy, the equipment is installed in separate facilities commensurable with the overall machine dimensions that consequently contributes to the increased noise activity. Therefore, the research data are of current interest for the enterprises of mechanical engineering, and they have both scholary interest and practical applicability. Discussion and Conclusions. It should be noted that the data obtained on the regular engine lathes, i.e. on round work pieces, are a particular case and are not applicable to the assembly of such complex geometrics as wheelpairs of rolling stock and various types of cranes. The implemented measurements show that under BRH, sound pressure levels exceed health standards by 5 to 15 dB of the high-frequency part of 500-8000 Hz spectrum, i.e. in the range in which the maximum permissible levels should not exceed 78-69 dB.

Design of permanent magnet synchronous generators for wave power generation

In this paper, a design method for ocean wave permanent magnet synchronous generator(PMSG)is proposed with new performance criteria to obtain better output performance at the cost of less permanent magnet material. Besides, a simple equivalent analytical geometry method is put forward to calculate the sizes of permanent magnets. Based on geometric and electromagnetic models, four types of rotor structures are compared, i.e., embedded, tangential, tile surface mount and convex surface mount structures. The designs and comparisons of machine are performed with the same permanent magnet volume. Moreover, the influences of mechanical pole-arc coefficient of tile surface mount PMSG on electrical efficiency, output power, material corrosion, core loss, and torque ripple are investigated. Finite-element analysis method is applied to verify the results using Ansoft/Maxwell.

Metallic TIM Testing and Selection for IC, Power, and RF Semiconductors

Metallic TIM Testing and Selection for IC, Power, and RF Semiconductors

Finite element analysis of expansion-matched submounts for high-power laser diodes packaging

In order to improve the output power and increase the lifetime of laser diodes, expansion-matched submounts were investigated by finite element analysis. The submount was designed as sandwiched structure. By varying the vertical structure and material of the middle layer, the thermal expansion behavior on the mounting surface was simulated to obtain the expansion-matched design. In addition, the thermal performance of laser diodes packaged by different submounts was compared. The numerical results showed that, changing the thickness ratio of surface copper to middle layer will lead the stress and junction temperature to the opposite direction. Thus compromise needs to be made in the design of the vertical structure. In addition, the silicon carbide (SiC) is the most promising material candidate for the middle layer among the materials discussed in this paper. The simulated results were aimed at providing guidance for the optimal design of sandwich-structure submounts.

DESIGN OF BACKUP STIFFNESS BRACKET AND INERTIAL MASS SURFACE FOR TESTING AIRCRAFT AIRBRAKE ACTUATOR

Abstract All aircraft motion or maneuvers are regulated by control surfaces which are operated by the pilot from the cockpit. The flight control surfaces are classified into primary control surfaces and secondary control surfaces. Airbrake is a secondary control surface. For operating the airbrake, a linear hydraulic actuator is used. This airbrake actuator has to undergo Hydro Mechanical Oscillation (HMO) test with backup mounting and airbrake surface inertia similar to that of the aircraft. In order to ascertain the stability of operation of the actuators throughout the operating frequency range, HMO test will have to be carried out mandatorily for all airbrake actuators. The test setup for HMO consists of an equivalent airbrake surface along with the actuator and backup stiffness bracket as same as that of aircraft surface. In order to validate the backup stiffness bracket a known force is applied on the bracket and deflection due to this force is noted. The stiffness obtained thereafter shall be same as that of aircraft backup stiffness. Also the equivalent airbrake surface used during the test shall have the same weight, center of gravity and inertia as that of actual aircraft airbrakes. In this paper, the design of backup stiffness bracket for airbrake actuator is been detailed. The validation of design is done theoretically as well as by using CATIA V5 R21 CAD package.

Robust inspection technique for detection of flatness defects of oil pans

This paper discusses two different methods for the detection of flatness defects present on the mounting surfaces of oil pans using laser-scanned point clouds. The first method involves registration, which is a widely used method in the field of 3D data inspection: scanned point clouds are registered with CAD data and the iterative closest point (ICP) algorithm is used for further comparison. The second method is our proposed method, a simple yet effective method for measuring the flatness of an oil pan mounting surface. The process is based on the construction of a reference plane on the scanned surface. The oil pan mounting surface is scanned by a 3D laser scanner, obtaining point cloud data that is then further processed to reduce noise. Using this processed data, a reference plane parallel to the direction of the mounting surface is defined at the mean position of the mounting surface. The direction of the reference plane is determined by the normal vector of the mounting surface. Construction of the reference plane is carried out by the singular value decomposition (SVD) technique. The deviation of the surface from the reference plane is measured by calculating the error distance between the points of the surface to the reference plane using the least-squares method.

Nested trampoline resonators for optomechanics

Two major challenges in the development of optomechanical devices are achieving a low mechanical and optical loss rate and vibration isolation from the environment. We address both issues by fabricating trampoline resonators made from low pressure chemical vapor deposition Si3N4 with a distributed Bragg reflector mirror. We design a nested double resonator structure with 80 dB of mechanical isolation from the mounting surface at the inner resonator frequency, and we demonstrate up to 45 dB of isolation at lower frequencies in agreement with the design. We reliably fabricate devices with mechanical quality factors of around 400 000 at room temperature. In addition, these devices were used to form optical cavities with finesse up to 181 000 ± 1000. These promising parameters will enable experiments in the quantum regime with macroscopic mechanical resonators.

Mounting of accelerometers with structural adhesives: Experimental characterization of the dynamic response

ABSTRACTThe use of accelerometers to monitor the vibrations of either complex machinery or simple components involves some considerations about the mounting of the sensor to the structure. Different types of mounting solutions are commonly used, but in all cases they can be classified in one of these categories: stud mounting, screw mounting, adhesive mounting, magnetic mounting, and probe sensing. Indeed, each of them has a specific field of application depending on e.g. the mounting surface conditions, the temperature, the accessibility to the specific mounting point, etc. The choice of the mounting solution has an important effect on the accuracy of the usable frequency response of the accelerometer, since the higher the stiffness of the fixing, the higher the low-pass frequency limit of the mounting. This article specifically focuses on adhesive mounting of accelerometers, which includes a great number of different products from the temporary adhesives like the beeswax to the permanent ones like cyanoacrylate polymers. Among the variety of commercial adhesives, three specific products have been experimentally compared to assess their transmissivity and the results are reported in this article. A two-component methylmethacrylate (HBM X60), a modified silane (Terostat 737), and a cyanoacrylate (Loctite 454) adhesive have been used to join two aluminum bases, one connected to an accelerometer and the other to the head of electromagnetic shaker. A design of experiment (DOE) approach was used to test the system at several levels of amplitude and frequency of the external sinusoidal excitation supplied by the shaker.