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Model reduction of contact dynamics simulation using a modified Lyapunov balancing method

Jianxun LIANG, Ou MA, Caishan LIU

《机械工程前沿(英文)》 2011年 第6卷 第4期   页码 383-391 doi: 10.1007/s11465-011-0244-9

摘要:

Finite element models are often used to simulate impact and contact dynamics responses of multibody dynamical systems. However, such a simulation remains very inefficient because very small integration time step must be used when solving the involved differential equations, especially when the involved contact stiffness is high. Although many model reduction techniques have been available to improve the efficiency of finite element based simulations, these techniques cannot be readily applied to contact dynamics simulations due to the high nonlinearity of the contact dynamics models. This paper presents a model reduction approach for finite-element based multibody contact dynamics simulation, based on a modified Lyapunov balanced truncation method. An example is presented to demonstrate that, by applying the model reduction the simulation process is significantly speeded up and the resulting error is bounded within an acceptable level. The performance of the method with respect to some influential factors such as element size, shape and contact stiffness is also investigated.

关键词: contact dynamics     dynamic simulation     model reduction     finite element method    

Model test and discrete element method simulation of shield tunneling face stability in transparent clay

Huayang LEI, Yajie ZHANG, Yao HU, Yingnan LIU

《结构与土木工程前沿(英文)》 2021年 第15卷 第1期   页码 147-166 doi: 10.1007/s11709-020-0704-6

摘要: The stability of the shield tunneling face is an extremely important factor affecting the safety of tunnel construction. In this study, a transparent clay with properties similar to those of Tianjin clay is prepared and a new transparent clay model test apparatus is developed to overcome the “black box” problem in the traditional model test. The stability of the shield tunneling face (failure mode, influence range, support force, and surface settlement) is investigated in transparent clay under active failure. A series of transparent clay model tests is performed to investigate the active failure mode, influence range, and support force of the shield tunneling face under different burial depth conditions, whereas particle flow code three-dimensional numerical simulations are conducted to verify the failure mode of the shield tunneling face and surface settlement along the transverse section under different burial depth conditions. The results show that the engineering characteristics of transparent clay are similar to those of soft clay in Binhai, Tianjin and satisfy visibility requirements. Two types of failure modes are obtained: the overall failure mode (cover/diameter: / ≤1.0) and local failure mode ( / ≥2.0). The influence range of the transverse section is wider than that of the longitudinal section when / ≥2.0. Additionally, the normalized thresholds of the relative displacement and support force ratio are 3%–6% and 0.2–0.4, respectively. Owing to the cushioning effect of the clay layer, the surface settlement is significantly reduced as the tunnel burial depth increases.

关键词: shield tunneling face     stability     transparent clay     model test     numerical simulation    

Machine learning and neural network supported state of health simulation and forecasting model for lithium-ion

《能源前沿(英文)》 doi: 10.1007/s11708-023-0891-7

摘要: As the intersection of disciplines deepens, the field of battery modeling is increasingly employing various artificial intelligence (AI) approaches to improve the efficiency of battery management and enhance the stability and reliability of battery operation. This paper reviews the value of AI methods in lithium-ion battery health management and in particular analyses the application of machine learning (ML), one of the many branches of AI, to lithium-ion battery state of health (SOH), focusing on the advantages and strengths of neural network (NN) methods in ML for lithium-ion battery SOH simulation and prediction. NN is one of the important branches of ML, in which the application of NNs such as backpropagation NN, convolutional NN, and long short-term memory NN in SOH estimation of lithium-ion batteries has received wide attention. Reports so far have shown that the utilization of NN to model the SOH of lithium-ion batteries has the advantages of high efficiency, low energy consumption, high robustness, and scalable models. In the future, NN can make a greater contribution to lithium-ion battery management by, first, utilizing more field data to play a more practical role in health feature screening and model building, and second, by enhancing the intelligent screening and combination of battery parameters to characterize the actual lithium-ion battery SOH to a greater extent. The in-depth application of NN in lithium-ion battery SOH will certainly further enhance the science, reliability, stability, and robustness of lithium-ion battery management.

关键词: machine learning     lithium-ion battery     state of health     neural network     artificial intelligence    

Reverse engineering in the construction of numerical simulation oriented patient-specific model of stented

Xianlong MENG, Wenyu FU, Yun ZHANG, Aike QIAO,

《机械工程前沿(英文)》 2010年 第5卷 第3期   页码 328-335 doi: 10.1007/s11465-010-0026-9

摘要: Patient-specific models are widely used in hemodynamic simulations. The flow in the boundary layer changes so strongly that fine meshes in the boundary layer are required in numerical simulations, especially for the calculation of wall shear stress and its gradient. To precisely analyze hemodynamics, it is necessary to investigate the approaches to the reconstruction of a numerical simulation-oriented patient-specific model for aortic arch aneurysm that can perform particular meshing in the boundary layer. Based on a surface model of aortic arch aneurysm in STL format, reverse engineering concept was applied to reconstruct a solid model using CAD software Geomagic and Pro/E, and a simplified model of stent for the intervention of aortic arch aneurysm was also created. After these models were imported to ANSYS, a block modeling approach was employed to divide the whole model into several domain blocks to adopt different meshing strategies. Particular meshing was performed especially in the boundary layer and around the stents. The finite element model particularly suitable for numerical simulation of hemodynamics was obtained. Hemodynamic simulation was performed, using the constructed finite element model to verify its applicability. The results indicate that reverse engineering concept and the proposed block modeling approach can be used to divide the solid model of aortic arch aneurysm into multiple volumes, which can be meshed according to particular requirements in each volume; the finite element model of stented aortic arch aneurysm can be employed to simulate hemodynamics. The approaches of modeling were applicable not only for aortic arch aneurysm, but also for similar model reconstruction as a reference in hemodynamic simulation investigations.

关键词: reverse engineering     aortic arch aneurysm     surface model     meshing     finite element model    

Numerical simulation on flow of ice slurry in horizontal straight tube

Shengchun LIU,Ming SONG,Ling HAO,Pengxiao WANG

《能源前沿(英文)》 2021年 第15卷 第1期   页码 201-207 doi: 10.1007/s11708-017-0451-0

摘要: Numerical simulation on flow of ice slurry in horizontal straight tubes was conducted in this paper to improve its transportation characteristics and application. This paper determined the influence of the diameter and length of tubes, the ice packing factors (IPF) and the flow velocity of ice slurry on pressure loss by using numerical simulation, based on two-phase flow and the granular dynamic theory. Furthermore, it was found that the deviation between the simulation results and experimental data could be reduced from 20% to 5% by adjusting the viscosity which was reflected by velocity. This confirmed the reliability of the simulation model. Thus, two mathematical correlations between viscosity and flow velocity were developed eventually. It could also be concluded that future rheological model of ice slurry should be considered in three sections clarified by the flow velocity, which determined the fundamental difference from single-phase fluid.

关键词: ice slurry     horizontal tubes     numerical simulation     pressure drop     viscosity model    

A biofilter model for simultaneous simulation of toluene removal and bed pressure drop under varied inlet

Jinying XI,Insun KANG,Hongying HU,Xian ZHANG

《环境科学与工程前沿(英文)》 2015年 第9卷 第3期   页码 554-562 doi: 10.1007/s11783-014-0671-z

摘要: In this study, a biofiltration model including the effect of biomass accumulation and inert biomass growth is developed to simultaneously predict the Volatile Organic Compounds (VOCs) removal and filter bed pressure drop under varied inlet loadings. A laboratory-scale experimental biofilter for gaseous toluene removal was set up and operated for 100 days with inlet toluene concentration ranging from 250 to 2500 mg?m . According to sensitivity analysis based on the model, the VOCs removal efficiency of the biofilter is more sensitive to Henry’s constant, the specific surface area of the filter bed and the thickness of water layer, while the filter bed pressure drop is more sensitive to biomass yield coefficient and original void fraction. The calculated toluene removal efficiency and bed pressure drop satisfactorily fit the experimental data under varied inlet toluene loadings, which indicates the model in this study can be used to predict VOCs removal and bed pressure drop simultaneously. Based on the model, the effect of mass-transfer parameters on VOCs removal and the stable-run time of a biofilter are analyzed. The results demonstrate that the model can function as a good tool to evaluate the effect of biomass accumulation and optimize the design and operation of biofilters.

关键词: Volatile Organic Compounds (VOCs)     biofilters     modelling     biomass accumulation     pressure drop    

Theoretical study on flow and radiation in tubular solar photocatalytic reactor

《能源前沿(英文)》 2021年 第15卷 第3期   页码 687-699 doi: 10.1007/s11708-021-0773-9

摘要: In this paper, based on the mixture flow model, an optimized six-flux model is first established and applied to the tubular solar photocatalytic reactor. Parameters influencing photocatalyst distribution and radiation distribution at the reactor outlet, viz. catalyst concentration and circulation speed, are also analyzed. It is found that, at the outlet of the reactor, the optimized six-flux model has better performances (the energy increase by 1900% and 284%, respectively) with a higher catalyst concentration (triple) and a lower speed (one third).

关键词: photocatalytic hydrogen photoreactor     nume- rical simulation     solar energy     flow model     radiation model    

Numerical simulation of fluid dynamics in the stirred tank by the SSG Reynolds Stress Model

Nana QI, Hui WANG, Kai ZHANG, Hu ZHANG

《化学科学与工程前沿(英文)》 2010年 第4卷 第4期   页码 506-514 doi: 10.1007/s11705-010-0508-7

摘要: The Speziale, Sarkar and Gatski Reynolds Stress Model (SSG RSM) is utilized to simulate the fluid dynamics in a full baffled stirred tank with a Rushton turbine impeller. Four levels of grid resolutions are chosen to determine an optimised number of grids for further simulations. CFD model data in terms of the flow field, trailing vortex, and the power number are compared with published experimental results. The comparison shows that the global fluid dynamics throughout the stirred tank and the local characteristics of trailing vortices near the blade tips can be captured by the SSG RSM. The predicted mean velocity components in axial, radial and tangential direction are also in good agreement with experiment data. The power number predicted is quite close to the designed value, which demonstrates that this model can accurately calculate the power number in the stirred tank. Therefore, the simulation by using a combination of SSG RSM and MRF impeller rotational model can accurately model turbulent fluid flow in the stirred tank, and it offers an alternative method for design and optimisation of stirred tanks.

关键词: stirred tank     fluid dynamics     numerical simulation     SSG Reynolds Stress Model     MRF    

Modeling and simulation of normal and hemiparetic gait

Lely A. LUENGAS,Esperanza CAMARGO,Giovanni SANCHEZ

《机械工程前沿(英文)》 2015年 第10卷 第3期   页码 233-241 doi: 10.1007/s11465-015-0343-0

摘要:

Gait is the collective term for the two types of bipedal locomotion, walking and running. This paper is focused on walking. The analysis of human gait is of interest to many different disciplines, including biomechanics, human-movement science, rehabilitation and medicine in general. Here we present a new model that is capable of reproducing the properties of walking, normal and pathological. The aim of this paper is to establish the biomechanical principles that underlie human walking by using Lagrange method. The constraint forces of Rayleigh dissipation function, through which to consider the effect on the tissues in the gait, are included. Depending on the value of the factor present in the Rayleigh dissipation function, both normal and pathological gait can be simulated. First of all, we apply it in the normal gait and then in the permanent hemiparetic gait. Anthropometric data of adult person are used by simulation, and it is possible to use anthropometric data for children but is necessary to consider existing table of anthropometric data. Validation of these models includes simulations of passive dynamic gait that walk on level ground. The dynamic walking approach provides a new perspective of gait analysis, focusing on the kinematics and kinetics of gait. There have been studies and simulations to show normal human gait, but few of them have focused on abnormal, especially hemiparetic gait. Quantitative comparisons of the model predictions with gait measurements show that the model can reproduce the significant characteristics of normal gait.

关键词: bipedal gait     biomechanics     dynamic walking     gait model     human gait     hemiparetic human gait    

Effect of adjusted mesoscale drag model on flue gas desulfurization in powder-particle spouted beds

《化学科学与工程前沿(英文)》 2022年 第16卷 第6期   页码 909-920 doi: 10.1007/s11705-021-2100-8

摘要: An energy minimum multiscale model was adjusted to simulate the mesoscale structure of the flue gas desulfurization process in a powder-particle spouted bed and verified experimentally. The obtained results revealed that the spout morphology simulated by the adjusted mesoscale drag model was unstable and discontinuous bubbling spout unlike the stable continuous spout obtained using the Gidaspow model. In addition, more thorough gas radial mixing was achieved using the adjusted mesoscale drag model. The mass fraction of water in the gas mixture at the outlet determined by the heterogeneous drag model was 1.5 times higher than that obtained by the homogeneous drag model during the simulation of water vaporization. For the desulfurization reaction, the experimental desulfurization efficiency was 75.03%, while the desulfurization efficiencies obtained by the Gidaspow and adjusted mesoscale drag models were 47.63% and 75.08%, respectively, indicating much higher accuracy of the latter technique.

关键词: adjusted mesoscale drag model     particle image velocimetry     water vaporization     desulfurization reaction     numerical simulation    

Modification of the activated sludge model for chemical dosage

Shuai MA,Siyu ZENG,Xin DONG,Jining CHEN,Gustaf OLSSON

《环境科学与工程前沿(英文)》 2015年 第9卷 第4期   页码 694-701 doi: 10.1007/s11783-014-0732-3

摘要: Full-scale experiments have been carried out to adapt the activated sludge model ASM2d to include the influence of metal dosage (Fe and Al ) for phosphorus removal. Phosphorus removal rates, nitrification rates, as well as pH and sludge settling performance, were evaluated as functions of the metal dosages. Furthermore, models relating certain parameters to the dosage of chemicals have been derived. Corresponding parameters in the ASM2d and the secondary settler models, included in the Benchmark Simulation Model No 1 (BSM1), have been modified to take the metal influence into consideration. Based on the effluent limits and penalty policy of China, an equivalent evaluation method was derived for the total cost assessment. A large number of 300-day steady-state and 14-day open-loop dynamic simulations were performed to demonstrate the difference in behavior between the original and the modified BSM1. The results show that 1) both in low and high mole concentrations, Fe addition results in a higher phosphorus removal rate than Al ; 2) the sludge settling velocity will increase due to the metal addition; 3) the respiration rate of the activated sludge is decreased more by the dosage of Al than Fe ; 4) the inhibition of Al on the nitrification rate is stronger than that of Fe ; 5) the total operating cost will reach the minimum point for smaller dosages of Fe , but always increase with Al addition.

关键词: chemical precipitation     benchmark simulation model     phosphorus removal     respiratory rate     sludge settling     activated sludge model    

A modified zone model for estimating equivalent room thermal capacity

Hua CHEN, Xiaolin WANG

《能源前沿(英文)》 2013年 第7卷 第3期   页码 351-357 doi: 10.1007/s11708-013-0254-x

摘要: The zone model has been widely applied in control analysis of heating, ventilation and air conditioning (HVAC) systems to achieve a high building efficiency. This paper proposed a modified zone model which is much simpler in the HVAC system simulation and has the similar accuracy to the complicated simulation model. The proposed model took into consideration the effect of envelop heat reservoir on the room indoor temperature by introducing the thermal admittance of the inner surfaces of the building enclosure. The thermal admittance for the building enclosure was developed based on the building thermal network analytical theory and transfer function method. The efficacy of the proposed model was demonstrated by comparing it with the complicated model — heat balance method (HTB2 program). The predicted results from the proposed model well agreed with those from the complicated simulation. The proposed model can then make the HVAC system dynamic simulation much faster and more acceptable for control design due to its simplicity and efficiency.

关键词: room model     thermal network analysis     transfer function     heating     ventilation and air conditioning (HVAC) system simulation    

Two-echelon Emergency Response Problem and Simulation Considering Secondary Disasters

Han-peng Zhang,Yi Liao,Hui-xia Luo

《工程管理前沿(英文)》 2014年 第1卷 第3期   页码 318-321 doi: 10.15302/J-FEM-2014042

摘要: It is necessary for subsequent resource distribution planning that get expected relief time considering secondary disasters after natural disaster. The goal of this research is to develop a two-echelon emergency resource distribution model under condition of secondary disasters. Taking minimal maximize relief time as criterion of relief performance, we developed response strategies and simulation model to get the expected value. Numerical studies of this paper presented the result of response strategies.

关键词: simulation     secondary disasters     two-echelon vehicle routing model    

Modeling and simulation of landfill gas production from pretreated MSW landfill simulator

Rasool Bux MAHAR,Abdul Razaque SAHITO,Dongbei YUE,Kamranullah KHAN

《环境科学与工程前沿(英文)》 2016年 第10卷 第1期   页码 159-167 doi: 10.1007/s11783-014-0685-6

摘要: The cumulative landfill gas (LFG) production and its rate were simulated for pretreated municipal solid waste (MSW) landfill using four models namely first order exponential model, modified Gompertz model, single component combined growth and decay model and Gaussian function. Considering the behavior of the pretreated MSW landfill, a new multi component model was based on biochemical processes that occurring in landfilled pretreated MSW. The model was developed on the basis of single component combined growth and decay model using an anaerobic landfill simulator reactor which treats the pretreated MSW. It includes three components of the degradation i.e. quickly degradable, moderately degradable and slowly degradable. Moreover, the developed model was statistically analyzed for its goodness of fit. The results show that the multi components LFG production model is more suitable in comparison to the simulated models and can efficiently be used as a modeling tool for pretreated MSW landfills. The proposed model is likely to give assistance in sizing of LFG collection system, generates speedy results at lower cost, improves cost-benefit analysis and decreases LFG project risk. It also indicates the stabilization of the landfill and helps the managers in the reuse of the landfill space. The proposed model is limited to aerobically pretreated MSW landfill and also requires the values of delay times in LFG productions from moderately and slowly degradable fractions of pretreated MSW.

关键词: combine growth and decay model     pretreated municipal solid waste (MSW)     multi component landfill gas (LFG) model    

Simulation and analysis of grinding wheel based on Gaussian mixture model

Yulun CHI, Haolin LI

《机械工程前沿(英文)》 2012年 第7卷 第4期   页码 427-432 doi: 10.1007/s11465-012-0350-3

摘要:

This article presents an application of numerical simulation technique for the generation and analysis of the grinding wheel surface topographies. The ZETA 20 imaging and metrology microscope is employed to measure the surface topographies. The Gaussian mixture model (GMM) is used to transform the measured non-Gaussian field to Gaussian fields, and the simulated topographies are generated. Some numerical examples are used to illustrate the viability of the method. It shows that the simulated grinding wheel topographies are similar with the measured and can be effective used to study the abrasive grains and grinding mechanism.

关键词: grinding wheel     3D topographies measurement     Gaussian mixture model     simulation    

标题 作者 时间 类型 操作

Model reduction of contact dynamics simulation using a modified Lyapunov balancing method

Jianxun LIANG, Ou MA, Caishan LIU

期刊论文

Model test and discrete element method simulation of shield tunneling face stability in transparent clay

Huayang LEI, Yajie ZHANG, Yao HU, Yingnan LIU

期刊论文

Machine learning and neural network supported state of health simulation and forecasting model for lithium-ion

期刊论文

Reverse engineering in the construction of numerical simulation oriented patient-specific model of stented

Xianlong MENG, Wenyu FU, Yun ZHANG, Aike QIAO,

期刊论文

Numerical simulation on flow of ice slurry in horizontal straight tube

Shengchun LIU,Ming SONG,Ling HAO,Pengxiao WANG

期刊论文

A biofilter model for simultaneous simulation of toluene removal and bed pressure drop under varied inlet

Jinying XI,Insun KANG,Hongying HU,Xian ZHANG

期刊论文

Theoretical study on flow and radiation in tubular solar photocatalytic reactor

期刊论文

Numerical simulation of fluid dynamics in the stirred tank by the SSG Reynolds Stress Model

Nana QI, Hui WANG, Kai ZHANG, Hu ZHANG

期刊论文

Modeling and simulation of normal and hemiparetic gait

Lely A. LUENGAS,Esperanza CAMARGO,Giovanni SANCHEZ

期刊论文

Effect of adjusted mesoscale drag model on flue gas desulfurization in powder-particle spouted beds

期刊论文

Modification of the activated sludge model for chemical dosage

Shuai MA,Siyu ZENG,Xin DONG,Jining CHEN,Gustaf OLSSON

期刊论文

A modified zone model for estimating equivalent room thermal capacity

Hua CHEN, Xiaolin WANG

期刊论文

Two-echelon Emergency Response Problem and Simulation Considering Secondary Disasters

Han-peng Zhang,Yi Liao,Hui-xia Luo

期刊论文

Modeling and simulation of landfill gas production from pretreated MSW landfill simulator

Rasool Bux MAHAR,Abdul Razaque SAHITO,Dongbei YUE,Kamranullah KHAN

期刊论文

Simulation and analysis of grinding wheel based on Gaussian mixture model

Yulun CHI, Haolin LI

期刊论文