scholarly journals Study of dynamics and rigidity of multifunctional coating of protective element of aircraft

2021 ◽  
Vol 5 (1) ◽  
pp. 86-94
Author(s):  
Keyword(s):  
Software Package ◽  
Operating Conditions ◽  
Vibration Modes ◽  
Structural Elements ◽  
Tabular Form ◽  
Space Technology ◽  
Structural Rigidity ◽  
Protective Element ◽  
Element Study ◽  
Protective Systems

In this work using a finite element study the author has numerically solved the problem of the dynamic behavior of a multifunctional coating of an aircraft protective element. The researcher conducted the simulation using the Femap with NX Nastran software package, The result of the modal analysis is the values and patterns of natural and secondary vibration modes of the multifunctional coating of the protective element of the aircraft using a special module the author has determined the distribution of effective modal masses in tabular form, Also, as a result of calculations, the author of the article obtained the value of the structural rigidity of the protective coating, The results presented in this work allow us to analyze the behavior of protective systems and structural elements of an aircraft with a multifunctional coating applied to the outer surface in real operating conditions, The design team can use the research results of this article in order to increase the efficiency of the development of a new structures and structures of a composite coating for multifunctional purposes, protective elements and materials for space technology

Tire Vibration Modes and Effects on Vehicle Ride Quality

1993 ◽  
Vol 21 (1) ◽  
pp. 23-39 ◽  
Author(s):  
R. W. Scavuzzo ◽  
T. R. Richards ◽  
L. T. Charek
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Operating Conditions ◽  
Modal Testing ◽  
Ride Quality ◽  
Vibration Modes ◽  
Inflation Pressure ◽  
Passenger Cars ◽  
Element Modeling ◽  
Road Surfaces

Abstract Tire vibration modes are known to play a key role in vehicle ride, for applications ranging from passenger cars to earthmover equipment. Inputs to the tire such as discrete impacts (harshness), rough road surfaces, tire nonuniformities, and tread patterns can potentially excite tire vibration modes. Many parameters affect the frequency of tire vibration modes: tire size, tire construction, inflation pressure, and operating conditions such as speed, load, and temperature. This paper discusses the influence of these parameters on tire vibration modes and describes how these tire modes influence vehicle ride quality. Results from both finite element modeling and modal testing are discussed.

Recent Advances in Lower Bound Shakedown Analysis

2009 ◽  
Author(s):  
Dieter Weichert ◽  
Abdelkader Hachemi
Keyword(s):  
Finite Element ◽  
Lower Bound ◽  
Process Engineering ◽  
Operating Conditions ◽  
Structural Elements ◽  
Shakedown Analysis ◽  
Material Models ◽  
Practical Engineering ◽  
Safe Operating ◽  
New Algorithms

The special interest in lower bound shakedown analysis is that it provides, at least in principle, safe operating conditions for sensitive structures or structural elements under fluctuating thermo-mechanical loading as to be found in power- and process engineering. In this paper achievements obtained over the last years to introduce more sophisticated material models into the framework of shakedown analysis are developed. Also new algorithms will be presented that allow using the addressed numerical methods as post-processor for commercial finite element codes. Examples from practical engineering will illustrate the potential of the methodology.

Vibration-Based Crack Detection in L-Frames

2014 ◽  
Vol 658 ◽  
pp. 261-268
Author(s):  
Jean Louis Ntakpe ◽  
Gilbert Rainer Gillich ◽  
Florian Muntean ◽  
Zeno Iosif Praisach ◽  
Peter Lorenz
Keyword(s):  
Strain Energy ◽  
Crack Detection ◽  
Natural Frequencies ◽  
Vibration Modes ◽  
Structural Elements ◽  
Element Analysis ◽  
Accurate Localization ◽  
Mathematical Expressions ◽  
Measurement Results ◽  
Non Destructive

This paper presents a novel non-destructive method to locate and size damages in frame structures, performed by examining and interpreting changes in measured vibration response. The method bases on a relation, prior contrived by the authors, between the strain energy distribution in the structure for the transversal vibration modes and the modal changes (in terms of natural frequencies) due to damage. Using this relation a damage location indicator DLI was derived, which permits to locate cracks in spatial structures. In this paper an L-frame is considered for proving the applicability of this method. First the mathematical expressions for the modes shapes and their derivatives were determined and simulation result compared with that obtained by finite element analysis. Afterwards patterns characterizing damage locations were derived and compared with measurement results on the real structure; the DLI permitted accurate localization of any crack placed in the two structural elements.

scholarly journals The flexural strength of anisotropic composite plates with free edges

2021 ◽  
Vol 21 (1) ◽  
pp. 26-34
Author(s):  
Ashot G. Akopyan ◽  
Keyword(s):  
Composite Materials ◽  
Stress State ◽  
Classical Theory ◽  
Solid Mechanics ◽  
Composite Plates ◽  
Operating Conditions ◽  
Plate Bending ◽  
Structural Elements ◽  
Engineering Structures ◽  
Anisotropic Composite

Modern technology shows increased demands on the strength properties of machines, their parts, as well as various structures, reducing their weight, volume and size, which leads to the need to use anisotropic composite materials. Finding criteria to determine the ultimate strength characteristics of structural elements, engineering structures is one of the urgent problems of solid mechanics. Strength problems in structures are often reduced to finding out the nature of the local stress state at the vertices of the joints of the constituent parts. The solution of this urgent problem for composite anisotropic plates can be found in this article, where the author continues the research in this area, extending them to the bending of anisotropic composite plates. The aim of the work is to study the limit stress state of anisotropic composite plates in the framework of the classical theory of plate bending. The outer edges of the plate are considered to be free. Using the classical theory of anisotropic plate bending in the space of physical and geometric parameters, the hypersurface equations determining the low-stress zones for the edge of the contact surface of a composite cylindrical orthotropic plate are obtained. Modern technological processes of welding, surfacing, soldering and bonding allow to produce structural elements of monolithic interconnected dissimilar anisotropic materials. The combination of different materials with qualities corresponding to certain operating conditions opens up great opportunities to improve the technical and economic characteristics of machines, equipment and structures. It can contribute to a significant increase in their reliability, durability, reduce the cost of production and operation. On this basis, the solution proposed in this work can be useful to increase the strength of composite materials.

Application of processing fiber-plastic composite washing

2021 ◽  
Vol 2021 (23) ◽  
pp. 214-224
Author(s):  
Artur Onyshchenko ◽  
◽  
Mykola Garkusha ◽  
Оlena Deli ◽  
◽  
...  
Keyword(s):  
Composite Materials ◽  
Operating Conditions ◽  
Structural Elements ◽  
Washing Machine ◽  
Normative Documents ◽  
Plastic Composite ◽  
Fiber Plastic ◽  
Fiberglass Composite ◽  
Composite Bridge

Introduction. Innovative, new materials are increasingly used in transport construction, among which composite materials are becoming widespread.Small bridges and elements of large bridges, such as roadway slabs, pavements, railings, composite reinforcement, reinforcement elements, are made of composite materials.Recently, the use of polymer composite materials for the manufacture of lightly loaded structural elements of transport structures, such as lighting poles, drainage trays, railings.Much attention should be paid to the fiberglass composite railing, which has a number of advantages over traditional metal fencing. Unfortunately, at present there are no clearly defined in Ukraine regulations on fiberglass composite fencing, so this topic is relevant and necessary for the transport industry.Problem Statement. From the literature analysis it is established that the railings of highways and sidewalks are in difficult operating conditions, are constantly exposed to aggressive environments - water, chemicals, salts.Goal. Increasing the durability of the railing by using new materials.Results. The analysis of production of a fiberglass profile is carried out. On the basis of the conducted researches the general requirements to a protection of fiberglass composite washing machine are established. On the basis of the current normative documents the classification of a protection on a place of installation, type of filling of a skeleton, a method of fastening of risers is developed. The paper presents the main parameters and dimensions of the fence. Material requirements are set. Methods of control of a protection with establishment of a technique of test of a protection on resistance to action of horizontal and vertical loadings are developed. Recommendations on installation and installation of a protection of fiberglass composite washing machine are offered.Conclusions. The research results were used in the development of technical conditions for the protection of fiberglass composite washing machine.Keywords: road, composite, bridge, fencing, profile, fiberglass, artificial construction

The Influence of the Interference Effects on the Aerodynamic Characteristics of the Reentry Vehicle and Its Parachute System Structural Elements During Their Separation

2020 ◽  
pp. 54-64
Author(s):  
V.T. Kalugin ◽  
A.Y. Lutsenko ◽  
D.M. Slobodyanyuk
Keyword(s):  
Software Package ◽  
Stationary Flow ◽  
Aerodynamic Characteristics ◽  
Separation Flow ◽  
Structural Elements ◽  
Interference Effects ◽  
Reentry Vehicle ◽  
Gravitational Forces ◽  
Initial Separation ◽  
Parachute System

This work considers the aerodynamic characteristics of the reentry vehicle (RV) of a segmental-conical shape, and the parachute container hatch cover (PCHC) during its separation. Due to the aerodynamic interference, the hatch may collide with the RV. The authors propose a method of studying the aerodynamic characteristics of the PCHC and RV based on modelling using the dynamic mesh technology in the FlowVision software package. Stationary flow around the RV until the hatch cover separation, flow around the hatch cover and free flow are calculated. As the result of the calculations, the PCHC trajectories (excluding gravitational forces) under various initial separation conditions, as well as the aerodynamic characteristics of the RV are obtained. The cases when the hatch cover collides with the RV are identified.

Design of Ultrasonic Vibrator for Conformal Coating Spray in LED Packaging

2009 ◽  
Vol 79-82 ◽  
pp. 715-718
Author(s):  
Byeong Ho Son ◽  
Seung Bok Choi ◽  
Quoc Hung Nguyen ◽  
Seung Min Hong ◽  
Soo Jin Lee ◽  
...  
Keyword(s):  
Longitudinal Vibration ◽  
Flow Characteristics ◽  
Film Surface ◽  
Wave Theory ◽  
Operating Conditions ◽  
Vibration Modes ◽  
Element Analysis ◽  
Surface Theory ◽  
Conformal Coating ◽  
Fluid Flow Characteristics

This paper presents the design of ultrasonic vibrator utilizing a piezoelectric actuator. After describing a geometric configuration of the proposed atomizer, an analytical model of the ultrasonic atomizer is formulated by considering liquid film surface theory and wave theory. The dynamic analysis is then undertaken using a finite element analysis to determine principal longitudinal vibration modes. An optimization is performed by taking the amplitude of the tip displacement as an objective function. The fluid flow characteristics of the proposed atomizer is also analyzed under operating conditions through commercial software FLUENT.

scholarly journals Stages of information support of development of on-board equipment for spacecraft

2021 ◽  
Vol 5 (3) ◽  
pp. 166-176
Author(s):  
A. A. Kovel
Keyword(s):  
Experimental Testing ◽  
Electronic Devices ◽  
Operating Conditions ◽  
Information Support ◽  
Engineering Practice ◽  
Space Technology ◽  
Successful Operation ◽  
Radio Electronic ◽  
Stage Of Development ◽  
Onboard Equipment

The ground-experimental testing of the elements of space technology is a crucial stage in the creation of space products, in fact, this is the ground «flight» of the devices being created. And how well the operating conditions will be reproduced at this stage and the successful functioning of the devices under the expected conditions is ensured, its successful operation in real flight during the service life depends. The radio electronic devices of the onboard equipment of the spacecraft are one of the essential elements that ensure the fulfillment of target tasks, which should confirm their readiness for the forthcoming work at the stage of groundbased experimental testing. The article discusses the stages of information support for the development of spacecraft onboard equipment, showing the ways to improve the technology of ground-based experimental testing of spacecraft onboard equipment. It is shown that at the present stage of development of the space industry, it has become possible to introduce the methodology of mathematical planning of an experiment into engineering practice. A backlog of applied work on radio-electronic topics h as appeared, showing the possibility of revealing in a full factorial experiment the influence of internal uncontrollable parameters (factors) of electronic components on the experimental results. This removed the obstacle to the implementation of the capabilities of the method in research and improvement of radio electronic devices onboard equipment.

scholarly journals Determination of dynamic loading of bearing structures of freight wagons with actual dimensions

2021 ◽  
Vol 2 (7 (110)) ◽  
pp. 6-14
Author(s):  
Oleksij Fomin ◽  
Alyona Lovska
Keyword(s):  
Service Life ◽  
Dynamic Loading ◽  
Software Package ◽  
Equations Of Motion ◽  
Operating Conditions ◽  
Vertical Acceleration ◽  
Vertical Loading ◽  
Bearing Structure ◽  
Freight Wagons

The determination of the dynamic loading of the bearing structures of the main types of freight wagons with the actual dimensions under the main operating conditions is carried out. The inertial coefficients of the bearing structures of the wagons are determined by constructing their spatial models in the SolidWorks software package. Two cases of loading of the bearing structures of the wagons – in the vertical and longitudinal planes – have been taken into account. The studies were carried out in a flat coordinate system. When modeling the vertical loading of the bearing structures of wagons, it was taken into account that they move in the empty state with butt unevenness of the elastic-viscous track. The bearing structures of the wagons are supported by bogies of models 18-100. The solution of differential equations of motion was carried out by the Runge-Kutta method in the MathCad software package. When determining the longitudinal loading of the bearing structures of wagons, the calculation was made for the case of a shunting collision of wagons or a "jerk" (tank wagon). The accelerations acting on the bearing structures of the wagons are determined. The research results will help to determine the possibility of extending the operation of the bearing structures of freight wagons that have exhausted their standard service life. It has been established that the indicators of the dynamics of the load-carrying structures of freight wagons with the actual dimensions of the structural elements are within the permissible limits. So, for a gondola wagon, the vertical acceleration of the bearing structure is 4.87 m/s2, for a covered wagon – 5.5 m/s2, for a flat wagon – 5.8 m/s2, for a tank wagon – 4.25 m/s2, for a hopper wagon – 4.5 m/s2. The longitudinal acceleration acting on the bearing structure of a gondola wagon is 38.25 m/s2, for a covered wagon – 38.6 m/s2, for a flat wagon – 38.9 m/s2, for a tank wagon – 27.4 m/s2, for a hopper wagon – 38.5 m/s2. This makes it possible to develop a conceptual framework for restoring the effective functioning of outdated freight wagons. The conducted research will be useful developments for clarifying the existing methods for extending the service life of the bearing structures of freight wagons that have exhausted their standard resource

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