Journal articles: 'VARING LOAD CONDITIONS'

1

Lee. "Analysis of segment lining cracking load considering axial force by varying boundary condition." Journal of Korean Tunnelling and Underground Space Association 16, no. 2 (2014): 173. http://dx.doi.org/10.9711/ktaj.2014.16.2.173.

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Palmer, Kyle D., Mark A. Severy, Charles E. Chamberlin, Anthony J. Eggink, and Arne E. Jacobson. "Performance Analysis of a Biomass Gasifier Genset at Varying Operating Conditions." Applied Engineering in Agriculture 34, no. 1 (2018): 135–43. http://dx.doi.org/10.13031/aea.12414.

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Abstract. An All Power Labs PP20 gasifier generation set (Berkeley, Calif.) was tested to evaluate its suitability for powering biomass conversion technologies (BCT) at remote forest operations sites. Feedstock of the species tanoak (), coast redwood (), and Douglas fir () were tested at moisture contents of 15% and 25% (wet basis). The PP20 was connected to a load bank with five different load profiles designed to simulate possible BCT loads. Two parameters of power quality, voltage variability, and frequency deviation, were determined to be within acceptable limits. The unit also successfully powered a remote biochar operation in Branscomb, California. Emissions of the PP20, when compared to diesel generator regulations, would meet non-methane hydrocarbons (NMHC) and NOX requirements but exceed the CO emissions limits by a factor of ten. The CO emissions could be reduced by adding a catalytic converter. The results indicate that it is possible to use a PP20 unit to provide electric power for the highly variable loads of a BCT system. Keywords: Bioenergy, Biomass conversion technology, Gasification, Renewable energy.

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Rittmann, Bruce E. "The Effect of Load Fluctuations on the Effluent Concentration Produced by Fixed-Film Reactors." Water Science and Technology 17, no. 2-3 (February 1, 1985): 45–52. http://dx.doi.org/10.2166/wst.1985.0118.

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Although time-varying loads to biological treatment processes are common, typical kinetic models are based on steady-state loads and conditions. This paper uses nonsteady-state kinetics to demonstrate the impact of load variations on the effluent concentration and load from fixed-bed biofilm reactors. The different responses for reactors having average loads that are high, intermediate, and low are compared. In most cases, time-varying input loading, in comparison with steady input loading, causes an increase in average effluent concentration; however, certain combinations of load variation and reactor type allow better performance than do steady-state loads.

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Sato, J. A., F. J. Vecchio, and H. M. Andre. "Scale-model testing of reinforced concrete under impact loading conditions." Canadian Journal of Civil Engineering 16, no. 4 (August 1, 1989): 459–66. http://dx.doi.org/10.1139/l89-075.

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Aspects of scaling theory relating to the response of reinforced concrete structures under impact load conditions are reviewed. Details for modelling concrete and reinforcement, to be consistent with similitude requirements, are also discussed. A test program is described in which models of varying size were constructed, drop tested, and compared with prototype response. An analysis of the test data is made, indicating that, within certain limitations, the predictions of scaling theory are applicable to reinforced concrete subjected to extreme impact loads. Key words: cracking, impact, loads, modelling, reinforced concrete, scaling, stresses, structures, tests.

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Arseneau, R. "The performance of demand meters under varying load conditions." IEEE Transactions on Power Delivery 8, no. 4 (1993): 1708–11. http://dx.doi.org/10.1109/61.248277.

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Zeng, Zhiping, Guanghui Hu, Xiangdong Huang, Weidong Wang, Ayoub Abdullah Senan Qahtan, Abdulmumin Ahmed Shuaibu, and Jundong Wang. "Statics performance of heavy-haul railway low-vibration track (LVT) under varying loading condition with the finite element method." Science Progress 104, no. 4 (October 2021): 003685042110363. http://dx.doi.org/10.1177/00368504211036330.

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Low-Vibration Tracks (LVTs) are widely used in subway tunnels for their excellent performance, but the application in heavy-duty railways still requires a lot of feasibility studies. In this study, the statics performance of LVT under different axle loads, load direction, and load position is explored using the finite element software Abaqus. The Timoshenk beam element and nonlinear spring element 3D solid element are used to represent rails, fasteners, and the other track structure respectively. The paper established the finite element model of LVT to study the mechanical characteristics of low vibration track structure under varying loading condition. The applied loads are determined according to the Heavy-Haul Railway Track Structure Design Code. The results shows: (1) The deformation and stress of the LVT structure show a linear relationship with the increase of the axle load. (2) Slab end loading and lateral load are more unfavorable to the stress and deformation of the track structure. When slab end is loaded with vertical load, the vertical load is distributed on four supporting blocks along the longitudinal direction with a ratio of 1:4:4:1, and the lateral direction is mainly borne by two adjacent fastener nodes with the total load proportion of 47% and 47% respectively. (3) The LVT structure can guarantee the safety of static performance under 30 t axle load and the maximum axle load should not exceed 36 t. The paper provides a guideline for the construction and maintenance of LVT structure in heavy haul railway.

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Feiyan Fan, Feiyan Fan, Jiazhen Hou Feiyan Fan, and Tanghuai Fan Jiazhen Hou. "Fault Diagnosis under Varying Working Conditions with Domain Adversarial Capsule Networks." 電腦學刊 33, no. 3 (June 2022): 135–46. http://dx.doi.org/10.53106/199115992022063303011.

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Most existing studies that develop fault diagnosis methods focus on performance under steady operation while overlooking adaptability under varying working conditions. This results in the low generalization of the fault diagnosis methods. In this study, a novel deep transfer learning architecture is proposed for fault diagnosis under varying working conditions. A modified capsule network is developed by combining the domain adversarial framework and classical capsule network to simultaneously recognize the machinery fault and working conditions. The novelty of the proposed architecture mainly lies in the integration of the domain adversarial mechanism and capsule network. The idea of the domain adversarial mechanism is exploited in transfer learning, which can achieve a promising performance in cross-condition fault diagnosis tasks. With the novel architecture, learned features exhibit identical or very similar distributions in the source and target domains. Hence, the deep learning architecture trained in one working condition can be applicable to discriminative conditions without being hindered by the shift between the two domains. The proposed method is applied to analyze vibrations of a bearing system acquired under different working conditions, i.e., loads and rolling speed. The experimental results indicate that the proposed method outperforms other state-of-the-art methods in fault diagnosis under varying working conditions.

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Mullings, Hannah, and Tim Stallard. "Impact of spatially varying flow conditions on the prediction of fatigue loads of a tidal turbine." International Marine Energy Journal 5, no. 1 (June 21, 2022): 103–11. http://dx.doi.org/10.36688/imej.5.103-111.

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Site development for tidal turbines relies upon a good understanding of the onset flow conditions, with disk averaged velocity typically used as a reference to define turbine power and mean loading. This work investigates the variation of onset flow conditions which occur for the same disk averaged velocity. Analysis builds upon data previously acquired during the measurement campaign conducted for the ReDAPT project using bed mounted ADCPs \cite{Sellar2018}. These measurements define the turbulence characteristics and vertical shear profiles over the rotor plane which are incorporated into an efficient blade element method for prediction of unsteady blade loads. This method allows efficient calculation of blade loading for multiple onset shear and turbulence profiles, each with the same disk average velocity, to determine the cyclic loading which contributes towards fatigue. Predictions of fatigue loads from measured profiles are compared with predictions from profiles predicted for the same location with a MIKE3 model \cite{Gunn2014}. Within the water depth two vertical positions are analysed, with vertical shear profiles from measurements and a multi-parameter model used to define the onset. For a near-bed location, use of the averaged predicted velocity profiles neglecting variation of turbulence intensity with flow-speed provides fatigue loads to within 1\% of predictions obtained using all measured profiles of velocity and corresponding turbulence intensity. For the near-surface location, the same approach under predicts fatigue loads by 16-19\%. This is partly due to the occurrence of a wider range of turbulence intensities. Since this is nearly constant with flow-speed a scaling factor is applied to load cycles from predicted profiles to estimate the aggregated fatigue load obtained using all measured conditions, providing confidence that accumulated fatigue loads can be predicted efficiently from velocity profiles obtained from shallow water models.

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Antoniadou, I., G. Manson, W. J. Staszewski, T. Barszcz, and K. Worden. "A time–frequency analysis approach for condition monitoring of a wind turbine gearbox under varying load conditions." Mechanical Systems and Signal Processing 64-65 (December 2015): 188–216. http://dx.doi.org/10.1016/j.ymssp.2015.03.003.

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Pichler, Kurt, Edwin Lughofer, Markus Pichler, Thomas Buchegger, Erich Peter Klement, and Matthias Huschenbett. "Fault detection in reciprocating compressor valves under varying load conditions." Mechanical Systems and Signal Processing 70-71 (March 2016): 104–19. http://dx.doi.org/10.1016/j.ymssp.2015.09.005.

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Hailu, Engidaw Abel, George Nyauma Nyakoe, and Christopher Maina Muriithi. "Application of Data-Driven Tuned Fuzzy Inference System for Static Equivalencing of Power Systems with High Penetration of Renewable Energy." Journal of Electrical and Computer Engineering 2022 (September 23, 2022): 1–19. http://dx.doi.org/10.1155/2022/2971960.

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To reduce the complexity of multiarea power systems during power flow study and security assessment, equivalencing of external power systems is essential. In this paper, external power systems are modeled as adaptive loads representing the tie-line flows varying with system operating conditions. The fuzzy inference system tuned by hybrid genetic-simulated annealing (HGSA-FIS) is proposed to predict the active and reactive power of adaptive loads from forecasted renewable energy (RE) generation and loads demand. The performance of proposed equivalent has been evaluated with an RTS-GMLC by comparing the power flow results in the internal system before and after equivalencing under varying RE and load demand scenarios. The results demonstrate the robustness of HGSA-FIS-based equivalent under varying RE generation and load demand. Furthermore, the proposed equivalent performs close to ANN-based equivalent and outperforms ANFIS-based equivalent. To practically implement the proposed approach, the neighboring system operators are required to exchange only the forecast data of RE generation and load demand, and the equivalent needs to be updated upon major grid changes.

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Pinarbasi, Seval, Fuad Okay, Erkan Akpinar, and Hakan Erdogan. "Stability Analysis of Two-Segment Stepped Columns with Different End Conditions and Internal Axial Loads." Mathematical Problems in Engineering 2013 (2013): 1–9. http://dx.doi.org/10.1155/2013/858906.

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Members with varying geometrical and/or material properties are commonly used in many engineering applications. Stepped columns with internal axial loads constitute a special case of such nonuniform columns. Crane columns in industrial buildings or structural columns supporting intermediate floors are important applications of stepped members in civil engineering. Since neither axial load nor stiffness is constant along the column height, the stability analysis of a stepped column is usually more complicated than that of a uniform column. Determination of exact buckling loads for stepped columns with different end conditions is not always practical. This paper shows that variational iteration method (VIM), a kind of analytical technique recently proposed for solution of nonlinear differential equations, can satisfactorily be used to obtain approximate solutions for buckling loads of stepped columns with internal axial loads. VIM solutions perfectly match with the exact solutions available in the literature for some special cases of two-segment stepped columns. For many other cases, that is, for various values of three design parameters, namely, (i) load ratio, (ii) stiffness ratio, and (iii) length ratio, approximate buckling loads for two-segment stepped columns are determined using VIM and presented in tabular form which can easily be used by design engineers.

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Afonaa-Mensah, Stephen, Qian Wang, and Benjamin B. Uzoejinwa. "Investigation of Daytime Peak Loads to Improve the Power Generation Costs of Solar-Integrated Power Systems." International Journal of Photoenergy 2019 (November 11, 2019): 1–12. http://dx.doi.org/10.1155/2019/5986874.

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Improving daytime loads can mitigate some of the challenges posed by solar variations in solar-integrated power systems. Thus, this simulation study investigated the different levels of daytime peak loads under varying solar penetration conditions in solar-integrated power systems to improve power generation cost performance based on different load profiles and to mitigate the challenges encountered due to solar variation. The daytime peak loads during solar photovoltaic generation hours were determined by measuring the solar load correlation coefficients between each load profile and the solar irradiation, and the generation costs were determined using a dynamic economic dispatch method with particle swarm optimization in a MATLAB environment. The results revealed that the lowest generation costs were generally associated with load profiles that had low solar load correlation coefficients. Conversely, the load profile with the highest positive solar load correlation coefficient exhibited the highest generation costs, which were mainly associated with violations of the supply-demand balance requirement. However, this profile also exhibited the lowest generation costs at high levels of solar penetration. This result indicates that improving daytime load management could improve generation costs under high solar penetration conditions. However, if the generation system lacks sufficient ramping capability, this technique could pose operational challenges that adversely impact power generation costs.

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Østergaard, Kasper Zinck, Jakob Stoustrup, and Per Brath. "Linear parameter varying control of wind turbines covering both partial load and full load conditions." International Journal of Robust and Nonlinear Control 19, no. 1 (January 10, 2009): 92–116. http://dx.doi.org/10.1002/rnc.1340.

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Patel, G., and A. N. Nayak. "Dynamic Instability Characteristics of Spherical Panels Subjected to linearly varying In-plane Loading." Proceedings of the 12th Structural Engineering Convention, SEC 2022: Themes 1-2 1, no. 1 (December 19, 2022): 1051–56. http://dx.doi.org/10.38208/acp.v1.619.

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The present paper reports the parametric instability phenomenon of spherical shell panels under linearly varying harmonic load employing finite element technique. An isoparametric curved element with eight nodes is considered in the formulation.. The sanders’ theory is used to model the spherical panel incorporating the properties of transverse shear and rotary inertia. A computer programme is created based on the formulation to carry out all essential calculations.The correctness of the formulation is established by comparing with results available in the literature.The impact of different parameters such as load factors, shallowness ratio on the instability regions of spherical panels with three support conditions such as SSSS (all edges simply supported), CCCC (all sides clamped) and CFCF (two opposite edges clamped and other two edges free) are studied. The study demonstrates that the parametric instability behavior of the spherical shell panels is significantly influenced by its shallowness parameter, boundary conditions and type of loads. These results will help the designers for deciding the dimensions of the spherical panels exposed to linearly varying periodic load at the time of the preliminary design.

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Bartelmus, W., and R. Zimroz. "Vibration condition monitoring of planetary gearbox under varying external load." Mechanical Systems and Signal Processing 23, no. 1 (January 2009): 246–57. http://dx.doi.org/10.1016/j.ymssp.2008.03.016.

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Ramasamy, Saravanakumar, Koperundevi Ganesan, and Venkadesan Arunachalam. "Power Flow Parameter Estimation in Power System Using Machine Learning Techniques Under Varying Load Conditions." International Journal of Electrical and Electronics Research 10, no. 4 (December 30, 2022): 1299–305. http://dx.doi.org/10.37391/ijeer.100484.

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In power transmission network state estimation is more complex and the measurements are critical in nature. Estimation of power flow parameters such as voltage magnitude and phasor angle in a power system is challenging when the loads are varying. The objective of the work is to estimate the voltage magnitude and phase angle using machine learning techniques. Some of the Machine learning techniques are decision trees (DT), support vector machines (SVM), ensemble boost (E-Boost), ensemble bags (E-bag), and artificial neural networks (ANN) are proposed in this work. Among these methods, the best machine learning techniques are selected for this study based on performance metrics. Performance metrics are Mean Square Error (MSE), Mean Absolute Error (MAE), and Root Mean Square Error (RMSE). Neural network produces minimum error when compared to other ML Techniques. Among three Performance Metrics MSE provides minimum error and is used to predict the exact model in this work. Therefore, it is concluded that the neural network can predict voltage and angle accurately under various load conditions in the power system effectively. Neural Network (NN) is applied to different load condition, and performance metrics are computed. To validate the proposed work, IEEE 14 and IEEE 30 bus systems are considered. The predicted value is compared to the actual value for all the load variation and residues are measured. The regression learner software in MATLAB is used to implement ML approaches in this work. The Outcome of this proposed work is used in phasor measurement units. The predicted value of voltage and angle using a neural network can be used to minimize the voltage magnitude and phase angle error in phasor Measurement Units (PMU).

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Kumar, Dileep, Sanaullah Mehran, Muhammad Zakir Shaikh, Majid Hussain, Bhawani Shankar Chowdhry, and Tanweer Hussain. "Triaxial bearing vibration dataset of induction motor under varying load conditions." Data in Brief 42 (June 2022): 108315. http://dx.doi.org/10.1016/j.dib.2022.108315.

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Patel, G., A. N. Nayak, and A. K. L. Srivastava. "Dynamic Instability Analysis and Design Charts of Curved Panels with Linearly Varying Periodic In-Plane Load." International Journal of Structural Stability and Dynamics 21, no. 09 (June 4, 2021): 2150130. http://dx.doi.org/10.1142/s0219455421501303.

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The present paper reports an extensive study on dynamic instability characteristics of curved panels under linearly varying in-plane periodic loading employing finite element formulation with a quadratic isoparametric eight nodded element. At first, the influences of three types of linearly varying in-plane periodic edge loads (triangular, trapezoidal and uniform loads), three types of curved panels (cylindrical, spherical and hyperbolic) and six boundary conditions on excitation frequency and instability region are investigated. Further, the effects of varied parameters, such as shallowness parameter, span to thickness ratio, aspect ratio, and Poisson’s ratio, on the dynamic instability characteristics of curved panels with clamped–clamped–clamped–clamped (CCCC) and simply supported-free-simply supported-free (SFSF) boundary conditions under triangular load are studied. It is found that the above parameters influence significantly on the excitation frequency, at which the dynamic instability initiates, and the width of dynamic instability region (DIR). In addition, a comparative study is also made to find the influences of the various in-plane periodic loads, such as uniform, triangular, parabolic, patch and concentrated load, on the dynamic instability behavior of cylindrical, spherical and hyperbolic panels. Finally, typical design charts showing DIRs in non-dimensional forms are also developed to obtain the excitation frequency and instability region of various frequently used isotropic clamped spherical panels of any dimension, any type of linearly varying in-plane load and any isotropic material directly from these charts without the use of any commercially available finite element software or any developed complex model.

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Venner, C. H., and Y. H. Wijnant. "Validation of EHL Contact Predictions under Time Varying Load." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 219, no. 4 (April 1, 2005): 249–61. http://dx.doi.org/10.1243/135065005x33865.

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In this paper, it is investigated how accurately current models predict the response of an elasto-hydrodynamically lubricated contact to time varying load conditions. For two patterns of time varying load, under conditions of pure rolling, the results obtained experimentally on a ball on disk interferometry apparatus by Sakamoto et al. (Behaviour of point contact EHL films under pulsating loads. Proceedings of the 30th Leeds-Lyon Symposium on Tribology, Elseviers Tribology Series, Vol. 43, pp. 391-399) are compared with the results of numerical simulations using the dynamic contact model of Wijnant (Contact dynamics in the field of elastohydro-dynamic lubrication. PhD Thesis, University of Twente, Enschede, The Netherlands, 1998 ISBN 90-36512239), Wijnant and Venner (Contact dynamics in starved elastohydrodynamic lubrication. Proceedings of the 25th Leeds-Lyon Symposium on Tribology, Elsevier Tribology Series, Vol. 36, pp. 705-716). The observed film changes are explained and related to the piezoviscous behaviour of the lubricant. Results for two different viscosity pressure relations are presented. It is shown that the details of the viscosity pressure relation have little effect on the local phenomena observed. The agreement between experimental and theoretical results is excellent in terms of the location and width of induced film thickness changes. The accuracy of the amplitude of the predicted changes is less. A amore accurate amplitude prediction requires more precise knowledge of the dynamic parameters, which describe the load system used in the experiments.

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Ding, Fangfang, and Zhigang Tian. "Integrated Prognosis for Wind Turbine Gearbox Condition-Based Maintenance Considering Time-Varying Load and Crack Initiation Time Uncertainty." International Journal of Reliability, Quality and Safety Engineering 28, no. 04 (February 23, 2021): 2150024. http://dx.doi.org/10.1142/s0218539321500248.

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Maintenance management in wind energy industry has great impact on the overall wind power cost. Maintenance services are either supported by wind turbine manufacturers within warranty period, or managed by wind farm owners. With condition-based maintenance (CBM) strategy, maintenance activities are scheduled based on the predicted health conditions of wind turbine components, and accurate prognostics methods are critical for effective CBM. The reported studies on integrated health prognostics considered the uncertainty in crack initiation time (CIT) uncertainty, but did not incorporate time-varying loading conditions, which could also have a significant impact on future health condition and remaining useful life (RUL) prediction. Constant loads were generally used to approximate the actual time-varying loading conditions. In this paper, an integrated prognostics method is proposed for wind turbine gearboxes considering both time-varying loading conditions and CIT uncertainty. As new condition monitoring observations are available, the distributions of both material model parameter and CIT are updated via Bayesian inference, and the failure time prediction is updated accordingly. An example is provided to demonstrate that the proposed time-varying load approach presents more benefits considering the uncertainty of CIT, with significant accuracy improvement comparing to the constant-load approach.

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Liu, Yunhai, Lei Chen, Bin Zhang, Zhongyue Cao, Pengfei Shi, Yong Peng, Ningning Zhou, Junyan Zhang, and Linmao Qian. "Key Role of Transfer Layer in Load Dependence of Friction on Hydrogenated Diamond-Like Carbon Films in Humid Air and Vacuum." Materials 12, no. 9 (May 12, 2019): 1550. http://dx.doi.org/10.3390/ma12091550.

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The friction of hydrogenated diamond-like carbon (H-DLC) films was evaluated under the controlled environments of humid air and vacuum by varying the applied load. In humid air, there is a threshold applied load below which no obvious friction drop occurs and above which the friction decreases to a relatively low level following the running-in process. By contrast, superlubricity can be realized at low applied loads but easily fails at high applied loads under vacuum conditions. Further analysis indicates that the graphitization of the sliding H-DLC surface has a negligible contribution to the sharp drop of friction during the running-in process under both humid air and vacuum conditions. The low friction in humid air and the superlow friction in vacuum are mainly attributed to the formation and stability of the transfer layer on the counterface, which depend on the load and surrounding environment. These results can help us understand the low-friction mechanism of H-DLC film and define optimized working conditions in practical applications, in which the transfer layer can be maintained for a long time under low applied load conditions in vacuum, whereas a high load can benefit the formation of the transfer layer in humid air.

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Qian, Xia Yi, Chen Bo Yin, and Feng Ma. "Methods for Determining the Dynamic Load of the Shipbuilding Gantry Crane." Advanced Materials Research 605-607 (December 2012): 1288–94. http://dx.doi.org/10.4028/www.scientific.net/amr.605-607.1288.

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Aim at the difficulty in determining the dynamic load , dynamic problems were analyzed, including three mechanisms of the shipbuilding gantry crane of lifting、trolley running and cart running under the joint starting and braking by adopting the method for determining the dynamic load based on the vibration theory and the one for determining the dynamic load based on the virtual prototype.Dynamic models and virtual prototype model were established and the time-varying dynamic loads of mechanisms were determined under typical working conditions. The maximum dynamic load obtained provides a reference for the dynamic finite element analysis of the shipbuilding gantry crane.

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Pandey, Shruti, Bharti Dwivedi, and Anurag Tripathi. "Performance Analysis of Supercapacitor Integrated PV Fed Multistage Converter with SMC Controlled VSI for Different Load Conditions." International Journal of Power Electronics and Drive Systems (IJPEDS) 9, no. 2 (June 1, 2018): 757. http://dx.doi.org/10.11591/ijpeds.v9.i2.pp757-765.

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The proposed work comprises of an MPPT controlled Photovoltaic (PV) source, in conjunction with a supercapacitor, cascaded with a Sliding Mode Controlled (SMC) Inverter, supplying variable linear and nonlinear loads. The effects of varying solar irradiation and its intermittency have been effectively managed by the MPPT controlled boost converter and charge controlled supercapacitor respectively. The charge controller bucks and boosts the terminal voltage and realizes the power flow in a bidirectional manner. Seamless action has been obtained by the proposed model under varying irradiation and for varying load conditions. The performance of the SMC controlled Inverter, when compared with a PI controlled Inverter, has been found to be superior in terms of power quality and robustness of the supply system

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Pandey, Shruti, Bharti Dwivedi, and Anurag Tripathi. "Performance analysis of super capacitor integrated PV fed multistage converter with SMC controlled VSI for varying nonlinear load conditions." International Journal of Engineering & Technology 7, no. 1.8 (February 25, 2018): 174. http://dx.doi.org/10.14419/ijet.v7i1.8521.

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This work comprises of an MPPT (maximum power point tracking) controlled Photovoltaic (PV) source, in combination with a superca-pacitor, cascaded with a Sliding Mode Controlled (SMC) Inverter, which supplies varying nonlinear loads. The varying solar irradiation effects and its intermittency have been successfully managed by the boost converter controlled by MPPT and supercapacitor controlled by bidirectional converter. The bidirectional converter step down and step up the terminal voltage and provides the power flow in a bidirectional manner. The proposed model helps in obtaining the seamless action under changing irradiation and for varying load conditions. The performance of the SMC controlled Inverter, when compared with a PI controlled Inverter, has been found to be superior in terms of power quality and robustness of the supply system.

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Ye, Ming, Jian Zhang, and Jiaqiang Yang. "Bearing Fault Diagnosis under Time-Varying Speed and Load Conditions via Observer-Based Load Torque Analysis." Energies 15, no. 10 (May 11, 2022): 3532. http://dx.doi.org/10.3390/en15103532.

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Bearing fault is the most common failure in rotating machines, and bearing fault diagnosis (BFD) has been investigated using vibration, current, or acoustic signals. However, there are still challenges in some existing approaches. This study proposes a novel BFD method based on natural observer. Based on the analysis of the effects on the load torque signal caused by bearing faults in the permanent magnetic synchronous machine (PMSM), a modified natural observer was designed to reconstruct the load torque signal from electrical signals, acquiring a novel indicator without the additional sensor installed. Angular resampling was implemented to convert the non-stationary load torque signal into a stationary one to reduce the computational complexity. For full-auto diagnosis without human involvement, a threshold determination algorithm was also modified. Experimental validations were carried out under speed-varying and torque-varying conditions and were compared with phase current and q-axis current signals. The average signal-to-noise ratio (SNR) of the estimated load torque is about 8.65 times compared with the SNR of the traditional q-axis current. The effectiveness of the proposed method prior to the traditional PMSM bearing fault indicators is demonstrated by the order spectrum results.

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Witzani, M., and P. Pechtl. "Modeling of (Cogeneration) Power Plants on Time-Dependent Power Demands of the Consumer." Journal of Engineering for Gas Turbines and Power 118, no. 2 (April 1, 1996): 353–58. http://dx.doi.org/10.1115/1.2816596.

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This paper presents a planning tool where rigorous plant performance models are used to produce accurate plant performance data reflecting real plant operation under the loads specified by load demand curves. Cumulative figures such as total fuel consumption and production efficiency serve as the basis for a subsequent detailed economic analysis. Basic inputs to the model are the energy demand curves for a specific site on a daily, hourly, or even per minute basis. The plant performance model takes into account the varying load levels, ambient conditions, fuel price, and revenues from electric power delivered off-site. The load/performance simulator calculates plant performance and basic economic parameters at each point in time of the load demand curve to exactly match the given energy demand (Fig. 1). The results are critical economic data like cumulated fuel consumption and expenses, total energy production, and overall averaged plant efficiency. The performance model delivers detailed plant performance data on an overall plant as well as component level. The results reflect real plant operation under all varying conditions, hence produce highly significant performance and economic parameters.

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Salama, M. M. A., E. A. A. Mansour, A. Y. Chikhani, and R. Hackman. "Control of Reactive Power in Distribution Systems with an End-Load and Varying Load Condition." IEEE Power Engineering Review PER-5, no. 4 (April 1985): 50–51. http://dx.doi.org/10.1109/mper.1985.5528830.

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Salama, M. M. A., E. A. A. Mansour, A. Y. Chikhani, and R. Hackam. "Control of Reactive Power in Distribution Systems with an End-Load and Varying Load Condition." IEEE Transactions on Power Apparatus and Systems PAS-104, no. 4 (July 1985): 941–47. http://dx.doi.org/10.1109/tpas.1985.319095.

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Rehacek, Stanislav, Ivo Simunek, David Citek, and Jiri Kolisko. "Cementitious Composites in Severe Environmental Conditions - Dynamic Loading." Advanced Materials Research 1124 (September 2015): 69–75. http://dx.doi.org/10.4028/www.scientific.net/amr.1124.69.

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Structure and properties of cement composite are time-varying characteristics, depending among others on environmental conditions. The key idea of the project is a struggle for complex research of joint effect of physical, chemical and dynamic loads on the internal structure [8] of cement composite and understanding the correlation between changes in microstructure and macro-scale properties [5]. During the experimental program, specimens will be exposed to combined influence of freeze-thaw cycles [9], aggressive chemical agents and dynamic loading [7]. The aim is to create a theoretical basis for design of effective cement composites meant to be used in severe environmental conditions. Results of first dynamic load tests carried out on prismatic specimens (100x100x400 mm) are presented in this paper. The results are supplemented by ultrasonic measurement.

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Yuan, Liting, Zhiyi Wang, Yanyan Huang, and Xiaolong Wang. "Comparative Analysis on Load Characteristic of Intermittently Conditioned Buildings for Different Wall Insulation Forms." Energies 13, no. 18 (September 22, 2020): 4974. http://dx.doi.org/10.3390/en13184974.

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The Air-conditioning System (ACS), used in office buildings in the hot summer and cold winter zone of China, are always operate intermittently. The dynamic thermal behaviors of building walls with real climate conditions may be different from those with only the representative day’s climate conditions, due to the time varying nature of the climate, which will lead to the variation of the ACS loads. A numerical calculation was performed to analyze the effects of insulation form on heat behavior of external walls and ACS loads. The results indicate that cooling transmission load with inside insulation reaches its maximum value when the solar-air temperature in daytime is the highest, while that with outside insulation occurs at the time when the air temperature at night is the highest during summer. Heating transmission load for the wall with external and internal insulation both peaks in the day with lowest mean outdoor temperature during the last non-working period. Inside insulation can be considered a better way to reduce the peak load, peak-valley load difference and energy consumption.

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Arslan, Muhammad, Muhammad Farooq, Muhamamd Naqvi, Umair Sultan, Zia-ur-Rehman Tahir, Saad Nawaz, Nazim Waheed, et al. "Impact of Varying Load Conditions and Cooling Energy Comparison of a Double-Inlet Pulse Tube Refrigerator." Processes 8, no. 3 (March 19, 2020): 352. http://dx.doi.org/10.3390/pr8030352.

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Modeling and optimization of a double-inlet pulse tube refrigerator (DIPTR) is very difficult due to its geometry and nature. The objective of this paper was to optimize-DIPTR through experiments with the cold heat exchanger (CHX) along the comparison of cooling load with experimental data using different boundary conditions. To predict its performance, a detailed two-dimensional DIPTR model was developed. A double-drop pulse pipe cooler was used for solving continuity, dynamic and power calculations. External conditions for applicable boundaries include sinusoidal pressure from an end of the tube from a user-defined function and constant temperature or limitations of thermal flux within the outer walls of exchanger walls under colder conditions. The results of the system’s cooling behavior were reported, along with the connection between the mass flow rates, heat distribution along pulse tube and cold-end pressure, the cooler load’s wall temp profile and cooler loads with varied boundary conditions i.e. opening of 20% double-inlet and 40-60% orifice valves, respectively. Different loading conditions of 1 and 5 W were applied on the CHX. At 150 K temperature of the cold-end heat exchanger, a maximum load of 3.7 W was achieved. The results also reveal a strong correlation between computational fluid dynamics modeling results and experimental results of the DIPTR.

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Singh, Baljeet, and Jasmaninder Singh Grewal. "Study of dry wear behavior of Novel ferrous samples prepared by powder metallurgy method." Surface Topography: Metrology and Properties 10, no. 2 (April 14, 2022): 025003. http://dx.doi.org/10.1088/2051-672x/ac63d8.

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Abstract The sliding wear behavior of newly developed ferrous powder metallurgy samples was investigated under dry sliding conditions. Wear tests were conducted by varying the normal loads of 30 N, 40 N, and 50 N at a constant velocity of 1 m s−1 and then at a constant load of 30 N by varying the sliding velocities by 0.5 m s−1, 1 m s−1, and 2 m s−1 at room temperature. Furthermore, the variations in the wear rate and coefficient of friction at a constant sliding distance of 5400 m were studied at different normal loads keeping sliding velocity constant at 1 m s−1 as well as at different sliding velocities and maintaining normal load at 30 N. The wear characteristics were evaluated using weight loss measurements. The mechanism of wear was observed using a scanning electron microscope and compositional analysis using energy-dispersive X-ray spectroscopy (EDX). It was found that increased normal load had a dominant effect on the wear loss in comparison to increased sliding speed during the tribological testing of the powder metallurgy samples.

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Chaari, Fakher, Walter Bartelmus, Radoslaw Zimroz, Taher Fakhfakh, and Mohamed Haddar. "Effect of Load Shape in Cyclic Load Variation on Dynamic Behavior of Spur Gear System." Key Engineering Materials 518 (July 2012): 119–26. http://dx.doi.org/10.4028/www.scientific.net/kem.518.119.

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Transmissions including spur gears are widely used in several industrial applications. They are characterized by high efficiency and capability to transmit high torques. A special attention should be made for transmissions running under varying loading conditions which have to be well monitored. The presence of this variability associated with defects that may occur in the transmission will complicate its condition monitoring. The first step to overcome this difficulty is to identify and characterize the dynamic response of the transmission in healthy conditions subjected to variable loading conditions. In this paper, a model based approach is presented in order investigate the influence of the loading shape on the vibration characteristics of the transmission. A dynamic model of a one stage spur gear transmission including a time varying loading conditions is developed. Two cases of loading conditions are considered. A parametric study is achieved and main conclusions are discussed.

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35

Dung, Dao Van, and Le Kha Hoa. "Nonlinear analysis of buckling and postbuckling for axially compressed functionally graded cylindrical panels with the Poisson's ratio varying smoothly along the thickness." Vietnam Journal of Mechanics 34, no. 1 (March 1, 2012): 27–44. http://dx.doi.org/10.15625/0866-7136/34/1/426.

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In this paper an approximate analytical solution to analyze the nonlinear buckling and postbuckling behavior of imperfect functionally graded panels with the Poisson's ratio also varying smoothly along the thickness is investigated. Based on the classical shell theory and von Karman's assumption of kinematic nonlinearity and applying Galerkin procedure, the equations for finding critical loads and load-deflection curves of cylindrical panel subjected to axial compressive load with two types boundary conditions, are given. Especially, the stiffness coefficients are analyzed in explicit form. Numerical results show various effects of the inhomogeneous parameter, dimensional parameter, boundary conditions on nonlinear stability of panel. An accuracy of present theoretical results is verified by the previous well-known results.

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Yang, Hongjiu, Yang Yu, and Jinhui Zhang. "Angle tracking of a pneumatic muscle actuator mechanism under varying load conditions." Control Engineering Practice 61 (April 2017): 1–10. http://dx.doi.org/10.1016/j.conengprac.2017.01.008.

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Yang, Ming, and Viliam Makis. "ARX model-based gearbox fault detection and localization under varying load conditions." Journal of Sound and Vibration 329, no. 24 (November 2010): 5209–21. http://dx.doi.org/10.1016/j.jsv.2010.07.001.

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Thillikkani, S., and M. Nataraj. "Fatigue life prediction of heavy vehicle suspension system under varying load conditions." Advances in Mechanical Engineering 12, no. 11 (November 2020): 168781402096832. http://dx.doi.org/10.1177/1687814020968325.

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Leaf spring experiences frequent cyclic loading during working conditions. When design stage itself it is very essential to assess the fatigue life of the suspension system. It is important to consider and evaluate the key aspects of fatigue failure and life by using Finite Element Analysis (FEA) techniques to overcome these failures. This paper serves to stimulate the premature failure of the existing and proposed bracket model with generalized force elements under dynamic load conditions. Scanning Electron Microscope (SEM) was used to identify the bracket failure prone areas which indicate that the cyclic load in the suspension system is caused by rural area road-induced vibrations and bumps. This contributes to the increase of the fatigue fracture, which ends up with a bracket failure. The results indicated that the fatigue life of existing bracket is low for rough road conditions; the modified bracket has been optimized for the safe load conditions of the heavy vehicle suspension system

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Gruber, Elliott R., Kenneth A. Cunefare, Per W. Danzl, Kenneth A. Marek, and Michel A. Beyer. "Optimization of Single and Dual Suppressors Under Varying Load and Pressure Conditions." International Journal of Fluid Power 14, no. 3 (November 2013): 27–34. http://dx.doi.org/10.1080/14399776.2013.10801411.

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Seifi, Alireza, and Mohammad Reza Hesamzadeh. "A hybrid optimization approach for distribution capacitor allocation considering varying load conditions." International Journal of Electrical Power & Energy Systems 31, no. 10 (November 2009): 589–95. http://dx.doi.org/10.1016/j.ijepes.2009.03.029.

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Páczelt, István, and Zenon Mróz. "Analysis of Wear Processes for Periodic Loading." Key Engineering Materials 681 (February 2016): 117–41. http://dx.doi.org/10.4028/www.scientific.net/kem.681.117.

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In the paper a class of wear problems is considered, for which the contact zone is fixed on one of contacting bodies and translates on the surface of another body, like in the case of punch in relative translation on a substrate. In the case of constant normal loads interacting with the induced monotonic sliding, the steady state wear process is reached. In the case of fixed normal load and the reciprocal sliding condition the wear process tends to its steady periodic state. Similarly, for periodically varying normal load, a steady periodic state is reached for the case of monotonic sliding. A most general case occurs for in-phase or out-of-phase periodic variation of normal load interacting with the reciprocal sliding. The paper is aimed to provide further study of steady wear states by considering periodically varying normal load combined with monotonic or alternating sliding conditions. The illustrative examples demonstrate the contact pressure and wear distribution in steady states with application to brake wear analysis.

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Li, Ze. "Feasibility Study on the Wheel Set Wear Prediction Based on Simulation Analysis." Journal of Physics: Conference Series 2541, no. 1 (July 1, 2023): 012036. http://dx.doi.org/10.1088/1742-6596/2541/1/012036.

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Abstract For studying the influencing factors of wheel set wear on high-speed trains, a large number of simulation analyses have found that line conditions, speed, tread profile, adhesion coefficient, contact geometry, and other factors have varying degrees of impact on wheel wear. However, based on the difficulty of the wheel set dynamic measurement, it cannot be directly verified. By establishing a rigid-flexible dynamic model for high-speed trains, the correlation between wheel pair wear and wheel rail load under different working conditions was simulated and analyzed. A dynamometer wheel set is used to measure wheel set loads. The results show that there is a strong correlation between wheel and rail wear and wheel set load under different operating conditions, and the actual wheel set load is significantly affected by the measurement line. The simulated wheel rail load is similar to the measured load distribution characteristics. Therefore, it is obviously feasible to conduct wheel set wear simulation analysis based on measured track irregularity data, but it also puts forward higher requirements for measured track data.

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Bulycheva, Evgeniia, and Sergey Yanchenko. "Real-time harmonic identification under varying grid conditions." Serbian Journal of Electrical Engineering 18, no. 1 (2021): 29–48. http://dx.doi.org/10.2298/sjee2101029b.

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One of the challenges of the power quality management is a need for reliable harmonic identification in grids with multiple non-linear loads. This paper proposes a novel method to accurately determine time-varying harmonic contributions of non-linear loads to the total grid voltage distortion. The use of the invasive measurement approach and ternary pulse sequence as a stimuli guarantees an accurate assessment of harmonic contribution with the account for timevariating harmonic impacts. The application of proposed approach is demonstrated by means of time-domain grid simulation with implemented white-box model of a pulse sequence generator. Statistical estimation of the accuracy of the proposed approach as well as comparison with typical harmonic identification methods justify its effectiveness under non-stationary network conditions.

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Bala, Mohammad Irfan, and Mohammad Ahsan Chishti. "Comparative Analysis of Load Balancing Algorithms for Cloud Computing in IoT." International Journal of Sensors, Wireless Communications and Control 10, no. 4 (December 18, 2020): 551–58. http://dx.doi.org/10.2174/2210327909666191127094149.

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Background: Cloud computing is a widely adopted computing paradigm and its importance has increased multi-folds in the recent past due to the inception of Internet of Things (IoT). Objectives: Efficient load balancing techniques are required to optimize the use of the cloud resources although load balancing in cloud is known to be a NP-hard problem. Methods: This work focuses on multiple load balancing algorithms whose performance has been analysed and compared under varying load conditions. Results: Comparative analysis of 5 algorithms is given, among which max-min algorithm is found to be the best performing algorithm with approximately 28% better job finish time and 23% higher throughput than the worst performing algorithm (FCFS). Conclusion: Simulations have been performed in CloudSim under varying input loads and the performance has been analysed under multiple scenarios. All the simulations have pointed towards the superiority of Max-min algorithm over other algorithms. This work will prompt the researchers to further investigate into load balancing algorithms so that better results are achieved.

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Jamaluddin, Mohd Affiq Bin, Mohd Shahir Liew, and V. John Kurian. "Response of Monopod Platform under Extreme Wave in Malaysian Water." Applied Mechanics and Materials 567 (June 2014): 295–300. http://dx.doi.org/10.4028/www.scientific.net/amm.567.295.

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This paper investigated the structural response of an existing monopod platform under extreme wave condition in Malaysian water. The estimation of the response plays an important role in the design of offshore structure. In this investigation, in-place analysis is performed to measure the reliability of monopod structure owing to the extreme environmental load condition in Malaysian water.The response of the structure to the varying conditions of the structure and varying environmental loads directions are analysed using well defined in-place analysis method [1]. In the present analysis, the deflection of the structure is studied for the number of guyed wires supporting the structure and multi-direction of environmental loads applied onto the structure.

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Hakro, Muhammad Rehan, Aneel Kumar, Mujahid Ali, Agha Faisal Habib, Afonso R. G. de Azevedo, Roman Fediuk, Mohanad Muayad Sabri Sabri, Abdelatif Salmi, and Youssef Ahmed Awad. "Numerical Analysis of Shallow Foundations with Varying Loading and Soil Conditions." Buildings 12, no. 5 (May 23, 2022): 693. http://dx.doi.org/10.3390/buildings12050693.

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The load–deformation relationship under the footing is essential for foundation design. Shallow foundations are subjected to changes in hydrological conditions such as rainfall and drought, affecting their saturation level and conditions. The actual load–settlement response for design and reconstructions is determined experimentally, numerically, or utilizing both approaches. Ssettlement computation is performed through large-scale physical modeling or extensive laboratory testing. It is expensive, labor intensive, and time consuming. This study is carried out to determine the effect of different saturation degrees and loading conditions on settlement shallow foundations using numerical modeling in Plaxis 2D, Bentley Systems, Exton, Pennsylvania, US. Plastic was used for dry soil calculation, while fully coupled flow deformation was used for partially saturated soil. Pore pressure and deformation changes were computed in fully coupled deformation. The Mohr–Columb model was used in the simulation, and model parameters were calculated from experimental results. The study results show that the degree of saturation is more critical to soil settlement than loading conditions. When a 200 KPa load was applied at the center of the footing, settlement was recored as 28.81 mm, which was less than 42.96 mm in the case of the full-depth shale layer; therefore, settlement was reduced by 30% in the underlying limestone rock layer. Regarding settlement under various degrees of saturation (DOS), settlment is increased by an increased degree of saturation, which increases pore pressure and decreases the shear strength of the soil. Settlement was observed as 0.69 mm at 0% saturation, 1.93 mm at 40% saturation, 2.21 mm at 50% saturation, 2.77 mm at 70% saturation, and 2.84 mm at 90% saturation of soil.

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Langusch, J. J., and E. Matzner. "Long-term modelling of nitrogen turnover and critical loads in a forested catchment using the INCA model." Hydrology and Earth System Sciences 6, no. 3 (June 30, 2002): 395–402. http://dx.doi.org/10.5194/hess-6-395-2002.

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Abstract. Many forest ecosystems in Central Europe have reached the status of N saturation due to chronically high N deposition. In consequence, the NO3 leaching into ground- and surface waters is often substantial. Critical loads have been defined to abate the negative consequences of the NO3 leaching such as soil acidification and nutrient losses. The steady state mass balance method is normally used to calculate critical loads for N deposition in forest ecosystems. However, the steady state mass balance approach is limited because it does not take into account hydrology and the time until the steady state is reached. The aim of this study was to test the suitability of another approach: the dynamic model INCA (Integrated Nitrogen Model for European Catchments). Long-term effects of changing N deposition and critical loads for N were simulated using INCA for the Lehstenbach spruce catchment (Fichtelgebirge, NE Bavaria, Germany) under different hydrological conditions. Long-term scenarios of either increasing or decreasing N deposition indicated that, in this catchment, the response of nitrate concentrations in runoff to changing N deposition is buffered by a large groundwater reservoir. The critical load simulated by the INCA model with respect to a nitrate concentration of 0.4 mg N l–1 as threshold value in runoff was 9.7 kg N ha–1yr–1 compared to 10 kg ha–1yr–1 for the steady state model. Under conditions of lower precipitation (520 mm) the resulting critical load was 7.7 kg N ha–1yr–1 , suggesting the necessity to account for different hydrological conditions when calculating critical loads. The INCA model seems to be suitable to calculate critical loads for N in forested catchments under varying hydrological conditions e.g. as a consequence of climate change. Keywords: forest ecosystem, N saturation, critical load, modelling, long-term scenario, nitrate leaching, critical loads reduction, INCA

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Kishore, N. N., A. Ghosh, S. K. Rathore, and P. V. Kishore. "Finite Element Analysis of Quasi-static Contact Problems Using Minimum Dissipation of the Energy Principle." Journal of Applied Mechanics 61, no. 3 (September 1, 1994): 642–48. http://dx.doi.org/10.1115/1.2901508.

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There are many practical situations where two bodies are directly in contact and are subjected to dynamic or varying loads. The contact area and the contact conditions are functions of load and load history and are not known a priori at any load thus making the problems nonlinear. The conditions of contact are determined by the kinematic constraints and the Coulomb’s law of friction. Direct solutions do not give unique results if the load steps are large and the finite element mesh is coarse. In the present work a method using the principle of minimum dissipation of energy is proposed and is applied to finite element analysis of a two-dimensional elastic contact problem under quasi-static loading. A combined incremental and iterative procedure is adopted to solve this problem. The results obtained are in good agreement with physical reasoning. The proposed method obtains new results apart from greatly reducing computational time and efforts.

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N., Parthasarathi, Satyanarayanan K.S., Thamilarau V., and Prakash M. "Linear analysis of a three-dimensional multistorey steel-frame structure under varying temperatures." Journal of Structural Fire Engineering 10, no. 1 (February 28, 2019): 110–22. http://dx.doi.org/10.1108/jsfe-01-2018-0002.

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PurposeThe purpose of this study is progressive collapse behavior in buildings. It occurs due to removal/damage of a column by fire, blast or vehicle impact.Design/methodology/approachThe present study investigates the comparative behavior of 3D four-storey moment resisting steel frame using ABAQUS to predict the sensitivity of the structure in progressive collapse because of fire loads. Columns at different levels were given different temperature with reduced material properties and yield strength. Progressive collapse load combination was adopted as per General Service Administration guidelines. Corner, middle, intermediate, multiple corner and multiple intermediate columns were subjected to fire load separately.FindingsThe results for displacement, stress, shear force and axial force were captured and discussed.Originality/valueThe study covers linear analysis of steel frame because of different temperature. In linear analysis. columns were subjected to different temperature and their results were studied. Effect of temperature in the structure were captured because of different fire conditions.

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Oberreiter, Matthias, Stefan Fladischer, Michael Stoschka, and Martin Leitner. "A Probabilistic Fatigue Strength Assessment in AlSi-Cast Material by a Layer-Based Approach." Metals 12, no. 5 (April 30, 2022): 784. http://dx.doi.org/10.3390/met12050784.

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An advanced lightweight design in cast aluminium alloys features complexly shaped geometries with strongly varying local casting process conditions. This affects the local microstructure in terms of porosity grade and secondary dendrite arm spacing distribution. Moreover, complex service loads imply changing local load stress vectors within these components, evoking a wide range of highly stressed volumes within different microstructural properties per load sequence. To superimpose the effects of bulk and surface fatigue strength in relation to the operating load sequence for the aluminium alloy EN AC 46200, a layer-based fatigue assessment concept is applied in this paper considering a non-homogeneous distribution of defects within the investigated samples. The bulk fatigue property is now obtained by a probabilistic evaluation of computed tomography results per investigated layer. Moreover, the effect of clustering defects of computed tomography is studied according to recommendations from the literature, leading to a significant impact in sponge-like porosity layers. The highly stressed volume fatigue model is applied to computed tomography results. The validation procedure leads to a scattering of mean fatigue life from −2.6% to 12.9% for the investigated layers, inheriting strongly varying local casting process conditions.

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Journal articles on the topic 'VARING LOAD CONDITIONS'

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