Maintenance, Reliability and Condition Monitoring
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Application of A* algorithm in intelligent vehicle path planning
Get PDFPath planning is one of the important directions in the field of intelligent vehicles research. Traditional path planning algorithms generally use Dijkstra algorithm, Breadth-First-Search (BFS) algorithm and A* algorithm. Dijkstra algorithm is a search-based algorithm, which can search to an optimal path, but the disadvantage is too many expansion nodes, which leads to insufficient search efficiency. BFS algorithm is a heuristic search algorithm, which reduces the disadvantage of too many expansion nodes and improves the search efficiency by heuristic function. A* algorithm is a heuristic search algorithm that combines Dijkstra’s algorithm and BFS algorithm, which has higher search efficiency and can search to an optimal path at the same time, but it is still lacking in the search mode and smoothness of the planned route. This paper first introduces the general path planning algorithm, then introduces and analyzes the A* algorithm, and proposes improvement measures for its shortcomings; finally, the executability and effectiveness of the improved algorithm are tested using simulation, and compared with the traditional A* algorithm, and the results show that the improved A* algorithm has good effect on path planning of intelligent vehicles
Socio-political development of CC(U)S in the Baltic Sea region
Get PDFAccording to EU goals and the Paris Agreement, an urgent need exists to reduce CO2 emissions while still securing energy supply. Thus, the timely deployment of carbon capture and storage (CCS) is seemingly unavoidable, especially for the cement and steel industries. However, diverse perceptions of CCS among stakeholders such as experts, politicians, and laypeople exist that could hinder the deployment of the technology, not least in the Baltic Sea Region (BSR). Hence, this research discusses these diverse perceptions and their roots. Furthermore, when it comes to political developments of CCS, after the unprovoked Russian invasion of Ukraine, the whole process of the energy transition in the region is under shadow for the seemingly mid-term while the approach to the energy security and security of supply needs to be revisited. In other words, the countries of the BSR need to manage the energy crisis in the region while following their plans for decarbonisation. In this light, CCS is, therefore, an option to secure energy supply from undesired alternatives like fossil fuels for the short-term and also biomass while curbing CO2 emissions. In sum, this research also discusses the role of CCS in energy security and security of supply concerning the Russian invasion of Ukraine
Active damping control of HEVs using Ansys and Matlab/Simulink software
Get PDFThis paper presents Parallel Hybrid Electric Vehicles (HEVs) powertrain design as well as a motor-based control approach that is designed to control or reduce driveline oscillations by introducing a Proportional-Integral-Derivative (PID) controller and a Fuzzy logic sliding mode controller. Because the torque of the electric motor can be decreased or increased more quickly than that of the Internal Combustion Engine (ICE), the vibration increases significantly. To solve this problem, an electric motor control-based Active Damping Control (ADC) strategy is employed to assure smooth driveline function and provide seamless driving experience for the driver. First, the basic level modeling of a hybrid electric powertrain in Ansys Simplorer environment is created and the performance was studied during the certification drive cycle. Thus, the main components of the powertrain– traction motor, battery and ICE – are researched, and basic models were built. The components were developed based on the Ansys software by using an automotive system level behavioral HEV library with VHDL-AMS language built in Ansys Simplorer environment. In addition, comparison of both controllers was presented. The simulation results show that using the ADC reduces more than 30 % of the driveline oscillations, thereby improving the drivability of HEVs
Damage localization in beams based on the analysis of modal parameters
Get PDFThis paper presents a two-step method for damage localization in beams by combining natural frequencies and mode shapes. The general locations of the damage are first identified from an indicator developed using relative natural frequency change (RNFC) curves and the values of RNFCs. A curvature-mode-shape-based method is then utilized to determine the specific location of the damage in the second step. The proposed two-step method is verified by detecting damage in a simulated simply-supported beam. The identified damage location agrees well with the actual damage location. A strategy for fast and accurate damage localization based on general localization using natural frequencies and specific localization using mode shapes is the main novelty of the paper
Development and application of high-power advanced exploration drilling rig for coal mining TBM
Get PDFWith the continuous popularization and application of TBM equipment and technology in the field of coal mine, aiming at the problems of small torque and small propulsion of existing TBM advanced exploration drilling rigs for coal mine, which is difficult to drill long borehole, and lack of special high-power drilling equipment to match with it, a high-power drilling rig for coal mine TBM is developed. This paper introduces the structure of the drilling rig, analyzes the structure and principle of the luffing mechanism and the rotary table protection device, also the strength of the key parts. Through the application in Guineng Group Heilaga Juxin coal mine shows that this equipment has large torque and propulsion, the hydraulic system and operation mode meet the requirements of long-distance separate layout in TBM. The drilling rig has good stability and high efficiency, and can meet the various needs of long drilling for advanced exploration, which promotes the application of TBM equipment and technology in the field of coal mine
Effect of defect distribution on thermal expansion coefficient of eutectic composite ceramics
Get PDFBased on Eshelby’s equivalent inclusion theory, the four-phase model and the interaction direct derivative estimate, the prediction model of effective thermal expansion coefficient of composite containing multiple types of inclusion in anisotropic matrix was established. The effective thermal expansion coefficient of eutectic composite containing defects was calculated. And then the influence of defects and inclusions on the effective thermal expansion coefficient is discussed in detail. The results show that the influence of inclusions will be amplified by defects when there are multiple inclusions in the matrix. Therefore, the interaction direct derivative estimate cannot accurately predict the influence of defect distribution on thermal expansion coefficient of eutectic composite ceramics
Study on treatment of loess subgrade disease by cement mixing pile
Get PDFAffected by the difference of geological conditions, the cause of settlement of road subgrade is different, and the concealment of subgrade disease is strong. If it is not timely maintenance, it will cause the further development of subgrade disease. A finite element model is established to study the settlement control technology by using cement mixing pile for collapsible loess. The results showed that when the loess is relatively shallow and the cement mixing pile penetrates the loess, the settlement and post-construction settlement of the foundation are small, which can be controlled within the limits of the specification. The cement content of mixing pile should be selected according to different regions, moisture content and other indicators. For the loess with particularly high moisture content and organic matter content, the cement content and construction technology should be determined by indoor and on-site test pile
Reliability of quantitative risk models: a case study from offshore gas production platform
Get PDFIn response to the competing factors governing the operation of oil and gas facilities, i.e., the stringent safety and environmental regulations, and the challenging business environment that entails minimizing the running cost, a risk-based inspection (RBI) program became a vital part of all Asset Integrity Management (AIM) frameworks. The objective is to ensure asset mechanical integrity while optimizing the maintenance and inspection resources and minimizing production downtime. There are different risk models being used to manage operational risk for equipment. The decision-maker should be attentive to the subjectivity and reliability of the risk results to establish an adequate risk target that can achieve the ultimate goal of RBI by determining the cost-effective inspection and maintenance plan without compromising plant safety, integrity or reliability. This paper presents evaluations of the most quantitative RBI models through a case study from an offshore gas producing platform. A case study was implemented for topside equipment on an offshore platform. The study analyzed the impact of contributing factors to the probability of failure (PoF) model through a sensitivity analysis to quantify the reliability and subjectivity in the failure probabilities. A sensitivity analysis and comparison between both API consequence modelling methodologies (i.e., CoF level 1 and 2) were performed to manifest the reliability of risk results. The sensitivity analysis revealed the variance in the calculated risk and demonstrated that a risk target/threshold should be established based on the deployed risk model. Using the same risk target for different risk models cannot effectively define all equipment items that actually need more resources to mitigate the risk. And can result in omitting critical equipment which can jeopardize asset integrity and lead to major losses, or spend resources on unnecessary equipment
Forecasting rainfall and potential for repeated events to predict flood areas in Banten province, Indonesia
Get PDFIn a period of ten years, from 2011-2020 rainfall in Indonesia is relatively high, with annual rainfall between 460.5-4,627.4 mm. The high rainfall has implications for flooding in several provinces. During this period, almost every year several areas in Banten Province experienced floods. To predict areas of Banten Province that have the potential for flooding, forecasts of rainfall and the potential for repeated occurrences of high rainfall are carried out. In making the forecast, observations were made at the Serang Meteorological Station, the Budiarto Curug Meteorological Station, the South Tangerang Climatology Station, and the Tangerang Geophysics Station. Rainfall data from the four stations were analyzed by Fourier transform, Gumbel method and Mononobe method. Distribution analysis results obtained rainfall in Banten Province between 0.0-607.9 mm with the length of rainy days per month between 0-26 days. Then, the results of the Fourier transform analysis; Banten Province included a monsoon rain pattern with unimodial rainfall. Furthermore, the results of the analysis of the Gumbel method and the Mononobe method, Banten Province included the category of moderate rain and tended to be heavy, even extreme. Based on the results of the analysis using these two methods, in 2025 in Banten Province, it is predicted that 11 % heavy rain, 3 % very heavy rain and 1 % extreme rain are predicted. In that year, it is predicted that there will be 65 sub-districts in Banten Province that have the potential for flooding. The sub-districts that have the potential for flooding are mostly located in Serang Regency, Serang City, Tangerang City, and South Tangerang City. This potential flood is predicted to occur in: January, February, March, April, May, October and November
A comparative analysis of different approaches used for modelling and solving differential equations in Simulink/MATLAB
Get PDFIn the paper, two new methods are developed and examined to implement a transfer function based approach in solving differential equations with Non-Zero initial conditions. A significant amount of time and effort is needed for solving differential equations theoretically or manually. Also, the obtained mathematical solutions to equations that represent various dynamic systems provide no graphical picture of the result. Using Simulink/MATLAB for modeling differential equations make the task of analyzing the behavior of systems easy and quick for the user. Beside, symbolic solutions and visual plots/graphs of the simulated results can be easily obtained and analyzed. Simulink uses different approaches to model a dynamic system such as differential equations in time domain (integrators based) or transfer function based and state space based. The paper addresses and compares different approaches used in Simulink for implementing block diagram based mathematical models of differential equations with non-zero initial conditions. Customarily, a transfer function based approach is used for analyzing systems with zero initial conditions. The paper demonstrated how to use a transfer function based approach for solving differential equations with non-zero initial conditions and two ways are devised to successfully implement the approach. To conclude, dynamic behavior of circuit and systems is analyzed and examined by obtaining graphical solutions with different approaches for chosen system parameters