Journal of Mechatronics and Artificial Intelligence in Engineering
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Determining the position of two cracks in a cantilever beam using artificial neural networks
Get PDFDuring functioning time, structures such as beams are subjected to a variety of loads caused by the working conditions and environment, which can lead to the development of cracks. The current research is concerned with detecting the presence and location of two transverse breathing cracks, in cantilever beams. Starting from the known fact that damages produce a stiffness degradation in structures altering their dynamic parameters, we performed modal simulations of damaged beams to determine their natural frequencies. By using the simulation data, we trained an artificial neural network (ANN), using the feedforward backpropagation algorithm, that is capable to detect the presence of the cracks, their position and for the case when the damages are in proximity, the model can determine if the cracks occur on the same face or opposite faces
Application of distance field-based algorithm to adjacent spline surfaces for composite structures boundary modeling
Get PDFThe complex boundary modeling required for simulating composite materials was applied to a broad range of problems, including surface overlap and gap. A novel method for the simultaneous fitting of adjacent spline surfaces based on a distance field has been devised. The fitting method for spline surfaces was constructed using offline spline surface, facet simplification, and residual solid reconstruction. The distance field-based approach of simultaneous fitting of neighboring spline surfaces included producing a distance field for a spline surface and then applying that distance field to nearby spline surfaces. There would be junction and separation issues if neighboring spline surfaces were fitted individually. By simultaneously fitting the nearby spline surfaces with the aid of the equivalence surface of the distance field, it was feasible to avoid overlap and gap
Laser ultrasonic excitation using graphene heat dissipation film for ultrasonic detection of seismic physical model
Get PDFWith excellent thermal conductivity and unique two-dimensional structure, the graphene heat dissipation film (GHDF) has been a potential photoacoustic (PA) material for multiple applications. In this study, we apply the GHDF into laser ultrasonic detection of seismic physical model (SPM). The PA effect of the GHDF is theoretically analyzed and experimentally demonstrated. The GHDF is physically attached to the upper surface of SPM, and excited effectively by a 532 nm pulsed laser. Distinguishable layered echo signal of SPM verifies the feasibility of the ultrasonic excitation approach using GHDF. This work opens up a new application of GHDF in ultrasonic detection of SPM
Simulative analysis on large local deformation features of single-shell and double-shell cylinders subjected to underwater explosion
Get PDFSimulative studies on a series of the cylinders subjected to underwater explosion were presented using coupled acoustic-structural analysis in ABAQUS in order to analyze the large local deformation feature and the influence of the outer water tank. The results revealed that large inward local deformation occurs on the front side of the cylinder, and the plastic hinge locates near the boundary of the spherical projection of the explosion to the cylinder with an approximate elliptic type. The inner water and the outer shell’s thickness of double-shell cylinders have great influence on the large local deformation feature of the inner shell, and with the increase of the outer shell’s thickness, large local inward deformation occurs on the back side of the cylinder, which is caused by the local jet effect of the inner water. The research can provide reference to the design and assessment of underwater anti-explosion structures
Improvement of maintenance management through Lean Philosophy and Industry 4.0
Get PDFFor companies to be able not only to survive, but also to differentiate themselves in the current global market scenario, all their functional areas must be in line with short, medium, and long-term management objectives and policies. The performance and competitiveness of companies depend on the behaviour of their production system, so an ambitious and adequate maintenance management is necessary. In this way, companies seek to adopt new methodologies and approaches to maintenance management that allow them to prepare maintenance for the challenges of Lean Philosophy and Industry 4.0. The Lean philosophy aims to do more and more with less and less, that is, using less equipment, less human effort, less space, and time, trying to offer customers exactly what they want, at the right time. On the other hand, Industry 4.0 is based on intelligent factories with production processes with a computer interface between people, machines, and resources, through extensive communication networks that combine the virtual and the real world, to obtain all integrated processes generating thus a real-time information system. Thus, an adequate maintenance management system contributes not only to improve maintenance performance as well as the production system. The maintenance management system, when combined with Lean Philosophy and Industry 4.0 concepts, makes it more efficient and effective. To improve maintenance performance, a system that combines these three concepts is proposed
MPF based symmetric cipher performance comparison to AES and TDES
Get PDFThis paper presents a performance comparison of newly created matrix power function (MPF) based symmetric cipher realized in cipher-block chaining mode (CBC) with two other standardized ciphers namely AES-128 and triple DES. The encryption rate is compared using 64 bits arithmetic operations. It is shown that the proposed cipher has a significant advantage against compared ciphers. It is achieved by consuming more memory for MPF realization. Mentioned ciphers are compared using the central processing unit (CPU) the number of clock cycles required to encrypt fixed size plaintexts. This paper also includes a comparison of a number of operations required to encrypt plaintext as well as memory requirements for each of the ciphers with pre-determined parameters. The main difference between symmetric cipher based on MPF and other standardized ciphers mentioned in the paper is the ability to work with larger matrix entries in comparison to other algorithms as well as availability to parallelize the process of encrypting a single block
Numerical convergence of the family of flux-continuous schemes with variable quadrature (qu1,qu2) for single phase flow in porous media
No full textFinite-volume schemes, which honor pressure and flux-continuity conditions, is developed using double quadrature (qu1,qu2), referred as double family scheme. The scheme is applicable to solve the elliptic pressure equation used in reservoir simulation. Schemes are applicable on both regular cartesian and unstructured triangular meshes. The scheme is defined over a control-volume distributed formulation. The scheme can be applied to both diagonal and full permeability tensor elliptic pressure equation with discontinuous coefficients. The scheme removes the first order errors, which are introduced by standard reservoir simulation schemes when applied to full tensor flow. The scheme is quantified with help of a quadrature rule. When the scheme is applied to highly heterogeneous and anisotropic porous media it does not honor maximum principle resulting in unstable solution with oscillatory behavior. The numerical solution is termed non-monotonicity for high anisotropy ratios with results showing oscillations in the numerical pressure solution. In this paper a double (qu1,qu2) quadrature flux continuous schemes is presented, which with specific choice of quadrature (qu1,qu2) helps in improved stability of the numerical solutions. Numerical convergence of the scheme is also demonstrated with help of a number of numerical test cases and schemes impact on monotonicity behavior is also demonstrated with numerical examples
Hybrid energy efficiency mapping in major Saudi locations using small wind turbine-solar systems
Get PDFThe use of fossil fuels of all kinds, such as natural gas, coal and petroleum in energy production, is the main cause of environmental pollution from air, water and soil, which is the direct cause of acid rain, the destruction of forests, the acidity of lakes, and the extinction of many living creatures that could not resist what happened Burning this fuel is due to a change in the surrounding environment. From this, it becomes clear to us the need for new sources to produce clean energy that does not pollute the environment, and work must be developed on these new sources for use in the production of clean energy in the coming years. The purpose of this work is to determine the efficiency of vertical axis turbines to be among the components of a hybrid system (solar/wind) to generate electric power in the Kingdom of Saudi Arabia. The work seeks to answer the research question, what is the efficiency of vertical axis turbines in generating electricity within a hybrid system (solar/wind) to generate electric power in the Kingdom of Saudi Arabia. The aim of the work is to analyze the vertical axis turbines and determine efficiency within the hybrid system in the regions of Saudi Arabia. There are many renewable energy sources (wind, solar thermal energy, solar photovoltaic, biomass, small and large hydropower and geothermal energy). But their efficiency is not stable from time to time, so the idea of hybrid energy came to make up for the shortage, by integrating the energy source Renewables with one or more other sources of energy (In 1999, McGowan and Manwell (1999) presented a summary of WND-PV-DSL HPS progress in the United States.) whether it is a non-renewable or renewable source [1]
Determination of the amount of oil product vapours from the tank based on monitoring the operation of the breathing valve
Get PDFThe development of methods for calculating losses of oil and petroleum products vapours from the tank has been going on for a long time. Systems that allow for more accurate calculations are also being developed along the way. In each country, and sometimes in each company, there are their own methods for determining the loss of light hydrocarbon fractions from losses from the tank through the breathing valve. In addition, losses are divided into “working losses” and “standing losses”. In each technique, there are both pros and cons. The most characteristic disadvantage of each technique is its applicability only to the conditions in which it was developed, due to the presence of correction coefficients. This article proposes a new technique for determining the loss of hydrocarbons vapours from the tank through the breathing valve, both from “working losses” and from “standing losses”. In the course of the work, formulas were obtained for calculating the flow rate Q∆P,h through the breathing valve, which depends on the degree of opening of the pressure plate and overpressure. An experiment was conducted, instrumentally proving the application of the developed methodology. And also, the equipment is selected and recommendations on its installation and use are given
Service performance evaluation of long-span cable-stayed bridge based on health monitoring data
Get PDFService performance evaluation is of great significance to the safety, durability, and reliability of bridge engineering. Over the last decade, structural health monitoring (SHM) systems have been widely used for condition monitoring of cable-stayed bridges, massive monitoring data are measured and stored by the sensing subsystems, which provides the basis for service performance evaluation of bridge engineering. Meanwhile, the load test is a common method to assess the construction and service performance of bridges. Combined the SHM systems and a load test of a thousand-meter level cable-stayed bridge after ten years of service, this paper investigates the operating conditions of main structures, including bridge towers, main girders, and steel cables. 52 trucks were used to conduct a quasi-static load on three key sections of bridges. Meanwhile, the GPS displacement of towers and main girders, stress of the main girders and acceleration responses of cables were measured synchronously by the SHM systems. Based on the health monitoring data, the dynamic responses, structural deformation, and cable tension of the bridge were investigated and evaluated by comparing with the finite element (FE) model load test at construction stage. The results show that the service performance of the bridge is basically within the designed conditions