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An ultrasound-guided percutaneous electrical nerve stimulation regimen devised using Finite element modeling promotes functional recovery after median nerve transection

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Neural Regeneration Research 2023年第3期18卷 683-688页

作者： Xiao-Lei Chu Xi-Zi Song Yu-Ru Li Zi-Ren Wu Qi Li Qing-Wen Li Xiao-Song Gu Dong Ming Department of Rehabilitation Tianjin University Tianjin HospitalTianjinChina Academy of Medical Engineering and Translational Medicine Tianjin UniversityTianjinChina College of Exercise&Health Science Tianjin University of SportTianjinChina College of Precision Instruments and Optoelectronics Engineering Tianjin UniversityTianjinChina

Percutaneous electrical nerve stimulation of an injured nerve can promote and accelerate peripheral nerve regeneration and improve function.When performing acupuncture and moxibustion,locating the injured nerve using ultrasound before percutaneous nerve stimulation can help prevent further injury to an already injured nerve.However,stimulation parameters have not been standardized.In this study,we constructed a multi-layer human forearm model using Finite element modeling.Taking current density and activated function as optimization indicators,the optimal percutaneous nerve stimulation parameters were established.The optimal parameters were parallel placement located 3 cm apart with the injury site at the midpoint between the needles.To validate the efficacy of this regimen,we performed a randomized controlled trial in 23 patients with median nerve transection who underwent neurorrhaphy.Patients who received conventional rehabilitation combined with percutaneous electrical nerve stimulation experienced greater improvement in sensory function,motor function,and grip strength than those who received conventional rehabilitation combined with transcutaneous electrical nerve stimulation.These findings suggest that the percutaneous electrical nerve stimulation regimen established in this study can improve global median nerve function in patients with median nerve transection.

关键词： Finite element modeling median nerve transection nerve regeneration neurorehabilitation percutaneous electrical nerve stimulation peripheral nerve injury randomized controlled trial

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基于有限元的新型科学考察船振动响应分析

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Journal of Marine Science and Application 2022年第2期21卷 69-81页

作者：邹祥依江国和叶林昌 Merchant Marine College Shanghai Maritime University201306China Ship Department National Deepsea Center260000China Vibration and noise reduction Shanghai Marine Diesel Engine Research Institute200090China

To control the vibration level of ships under construction,MSC Software’s Patran&Nastran modeling solutions can be used to establish a detailed finite element model of a new manned submersible support mother ship based on a line drawing,including the deck layout,bulkhead section,and stiffener distribution.After a comprehensive analysis of the ship simulation conditions,boundaries,and excitation forces of the main operating equipment,modal analysis and calculation of the ship vibration can be conducted.In this study,we calculated and analyzed the vibration response of key points in the stern area of the ship’s main deck and the submersible warehouse area under design loading working conditions.We then analyzed the vibration response of typical decks(including the compass deck,steering deck,captain’s deck,forecastle deck,and main deck)under the main excitation forces and moments(such as the full swing pod and generator sets).The analysis results showed that under DESIDEP working conditions,the vibration of each deck and key areas of the support mother ship could meet the vibration code requirements of the ship’s preliminary design(using the pod excitation and generator sets).Similarly,the vibration response of a scientific research ship under other loading conditions also met the requirements of the code and provided data support for a comprehensive understanding of the ship’s vibration and noise levels.Using actual vibration measurements,the accuracy of the vibration level simulations using Finite element modeling was verified,the vibration of each area of the ship comfortably meeting the requirements of the China Classification Society.

关键词： Scientific research ship Vibration Modal analysis Risk assessment Finite element modeling

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Finite element modeling assumptions impact on seismic response demands of MRF-buildings

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Earthquake Engineering and Engineering Vibration 2018年第4期17卷 821-834页

作者： Shehata E Abdel Raheem Ahmed K Abdel Zaher Ahmed MA Taha Civil Engineering Department Engineering College Taibah University Civil Engineering Department Faculty of Engineering Assiut University

Recent seismic events have raised concerns over the safety and vulnerability of reinforced concrete moment resisting frame ＂RC-MRF＂ buildings. The seismic response of such buildings is greatly dependent on the computational tools used and the inherent assumptions in the modelling process. Thus, it is essential to investigate the sensitivity of the response demands to the corresponding modelling assumption. Many parameters and assumptions are justified to generate effective structural finite element（FE） models of buildings to simulate lateral behaviour and evaluate seismic design demands. As such, the present study focuses on the development of reliable FE models with various levels of refinement. The effects of the FE modelling assumptions on the seismic response demands on the design of buildings are investigated. the predictive ability of a FE model is tied to the accuracy of numerical analysis; a numerical analysis is performed for a series of symmetric buildings in active seismic zones. The results of the seismic response demands are presented in a comparative format to confirm drift and strength limits requirements. A proposed model is formulated based on a simplified modeling approach, where the most refined model is used to calibrate the simplified model.

关键词： RC-MRF buildings design codes provisions seismic design Finite element modeling modeling assumptions response demands

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Determination of the Normal Contact Stiffness and Integration Time Step for the Finite element modeling of Bristle-Surface Interaction

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Computers, Materials & Continua 2018年第7期56卷 169-184页

作者： Libardo V.Vanegas-Useche Magd M.Abdel-Wahab Graham A.Parker Facultad de Ingeniería Mecánica Universidad Tecnológica de Pereira.Pereira 660003Colombia Division of Computational Mechanics Ton Duc Thang UniversityHo Chi Minh CityVietnam Faculty of Civil Engineering Ton Duc Thang UniversityHo Chi Minh CityVietnam Soete Laboratory Faculty of Engineering and ArchitectureGhent UniversityTechnologiepark Zwijnaarde 903Zwijnaarde B-9052Belgium Faculty of Engineering and Physical Sciences University of Surrey.GuildfordUK

In Finite element modeling of impact,it is necessary to define appropriate values of the normal contact stiffness,Kn,and the Integration Time Step(ITS).Because impacts are usually of very short duration,very small ITSs are required.Moreover,the selection of a suitable value of Kn is a critical issue,as the impact behavior depends dramatically on this parameter.In this work,a number of experimental tests and finite element analyses have been performed in order to obtain an appropriate value of Kn for the interaction between a bristle of a gutter brush for road sweeping and a concrete surface.Furthermore,a suitable ITS is determined.The experiments consist of releasing a steel bristle that is placed vertically at a certain distance from a concrete surface and tracking the impact.Similarly,in the finite element analyses,a beam is modeled in free fall and impacting a surface;contact and target elements are attached to the beam and the surface,respectively.The results of the experiments and the modeling are integrated through the principle of conservation of energy,the principle of linear impulse and momentum,and Newton’s second law.The results demonstrate that,for the case studied,Kn and the impact time tend to be independent of the velocity just before impact and that Kn has a very large variation,as concrete is a composite material with a rough surface.Also,the ratio between the largest height of the bristle after impact and the initial height tends to be constant.

关键词： Brush street sweeping Finite element modeling contact mechanics

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Finite element modeling of consolidation process of Si C fiber-reinforced titanium matrix composites via matrix-coated fiber method

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Rare Metals 2015年第12期34卷 844-850页

作者： Xiang-Hong Xu Yan-Qing Yang Xian Luo Lin Qin Ju-Hong Lou Qing Sun Shazhou Polytechnic Institute of Technology State Key Laboratory of Solidification Processing Northwestern Polytechnical University

The consolidation process of SiCf/Ti-6Al-4V composites by matrix-coated fiber (MCF) method via hot pressing was investigated using Finite element modeling (FEM). By analyzing the elastic–plastic contact deformation of the representative aligned coated fibers, the consolidation maps delineating the time–temperature–pressure relationship for full densification were constructed. Both the flow coefficient and the contact area coefficient used to describe the contact deformation were calculated according to the model. In addition, the effect of fiber content on matrix stress distribution was analyzed. The results show that fiber content is a significant factor that influences the densification process. Higher fiber content will lower the consolidation rate.

关键词： Titanium matrix composites Consolidation Finite element modeling Matrix-coated fiber

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Finite element modeling of pore-fluid flow in the Dachang ore district,Guangxi,China:Implications for hydrothermal mineralization

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Geoscience Frontiers 2011年第3期2卷 463-474页

作者： Minghui Ju Chongbin Zhao Tagen Dai Jianwen Yang Computational Geosciences Research Center Central South University Changsha 410083 China The Key Laboratory of Chinese Education Ministry for Non-ferrous Metal Metallogenic Prediction Central South University Changsha 410083 China Department of Earth and Environmental Sciences University of Windsor Canada

Convective heat transfer associated with the circulation of porefluid in porous rocks and fractures within the upper crust of the Earth is substantial when the temperature gradient is sufficiently high. In order to understand the process of Snpolymetallic mineralization in the Dachang ore district of Guangxi, a finite element method has been used in this study to simulate both pore-fluid flow and heat transfer in this district. On the basis of related geological, tectonic and geophysical constraints, a computational model was established. It enables a computational simulation and sensitivity analysis to be carried out for investigating ore-forming pore-fluid flow and other key factors that may affect hydrothermal ore genesis in the district. The related simulation results have indicated that：（1） permeable fault zones in the Dacbang ore district can serve as preferential pathways for pore-fluid flow on a regional-scale; and （2） the pore-fluid flow can affect the salinity distribution. This latter factor is part of the reason why Sn-polymetallic mineralization has taken place in this district.

关键词： Finite element modeling Dachang ore district Hydrothermalmineralization Salinity-induced buoyancy

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A 3D Finite element modeling on the relationship between crustal stress and earthquake activity in Liaoning and its vicinity

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Acta Seismologica Sinica(English Edition) 2001年第1期14卷 25-37,117页

作者：李平卢良玉卢造勋潘科焦明若许忠淮 Institute of Geophysics China Seismological Bureau Beijing China Seismological Bureau of Liaoning Province Shenyang China

Based on the latest result in research on 3D seismic wave velocity structure of crust and uppermost mantle and taking geological setting and fracture zones into consideration, a 3D geological model for the studied region is built up. The boundary constraint and force loading boundary condition for the model are determined according to the characteristics of crustal stress field deduced from earthquake focal mechanism and in-situ stress measurement data. Using linear elastic material model a 3D Finite element modeling is conducted to study the characteristics of crustal stress field. A comparison analysis between the simulated stress field and earthquake locations reveals that the moderate and strong earthquakes generally occurred in the zones with high shear stress gradient. Furthermore, the paper notices a few potential earthquake-prone regions.

关键词： Liaoning and its vicinity tectonic stress field Finite element modeling

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Finite element modeling of Hydrostatic Stress Distribution in Copper Dual-damascene Interconnects

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Journal of Shanghai Jiaotong university(Science) 2011年第3期16卷 302-306页

作者：袁光杰陈冷 School of Materials Science and Engineering University of Science and Technology Beijing

Hydrostatic stresses of copper dual-damascene interconnects are calculated by a commercial finite element software in this paper.The analytical work is performed to examine the effects of different low-k(k is permittivity)dielectrics,barrier layer and aspect ratio of via on hydrostatic stress distribution in the copper interconnects.The results of calculation indicate that the hydrostatic stresses are highly non-uniform throughout the copper interconnects and the highest tensile hydrostatic stress exists on the top interface of lower level interconnect near via.Both the high coefficient of thermal expansion and the low elastic modulus of the low-k dielectrics and barrier layer can decrease the highest hydrostatic stress on the top interface,which can improve the reliability of the copper interconnects.

关键词： copper dual-damascene interconnects hydrostatic stress stress-induced voiding Finite element modeling

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Finite element modeling of Impact between Bus and Roadside Guardrail

Finite Element Modeling of Impact between Bus and Roadside G...

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The 4th International Forum of Automotive Traffic Safety

作者： ZHANG Fan1 2 WANG Dazhi1 ZHOU Qing1 ZHANG Jinhuan1 WANG Chengbiao2 ZHANG Ying3 BAI Shufeng3 LIANG Yaping3 1. State Key Laboratory of Automotive Safety and Energy Tsinghua University Beijing 100084 2. China University of Geosicences (Beijing) Beijing 100083 3. Beijing Zhonglu’an Traffic TechnologicaCo. Ltd Beijing 100071

Roadside guardrail on highway is an essential protecting device for preventing vehicles from accidentally running off the road. The guardrail should provide protection for both passenger cars and large vehicles such as buses and trucks. Finite element modeling is an effective and efficient design tool for simulating impact between guardrail and vehicle. A finite element model of 10 m long bus was developed for simulating the impact between the bus and a concrete guardrail. The required regulation test is an angular impact, in which the bus impacts with the guardrail at 20 degree and 80 km/h. Unlike a car crash test that typically lasts about 0.1 seconds, the vehicle-guardrail crash test needs to be monitored for one second or longer. This is a great challenge to the bus modeling in terms of balancing the structural details and computational efficiency. To better capture the impact response, the bus suspension, the tire rotation, the steering, and the tire pressure are also modeled. The simulation correlates well with the test results in the local deformation of the bus, and more importantly, in the post-impact trajectory of the bus.

关键词： Highway safety Bus Guardrail Impact Finite element modeling

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A novel mitigation measure for normal fault-induced deformations on pile-raft systems

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Earthquake Engineering and Engineering Vibration 2024年第1期23卷 15-33页

作者： Mohammadreza Jahanshahi Nowkandeh Mehdi Ashtiani Faculty of Civil Engineering Babol Noshirvani University of TechnologyBabolIran

Evidence from recent earthquakes has shown destructive consequences of fault-induced permanent ground movement on structures.Such observations have increased the demand for improvements in the design of structures that are dramatically vulnerable to surface fault ruptures.In this study a novel connection between the raft and the piles is proposed to mitigate the hazards associated with a normal fault on pile-raft systems by means of 3D finite element(FE)modeling.Before embarking on the parametric study,the strain-softening constitutive law used for numerical modeling of the sand has been validated against centrifuge test results.The exact location of the fix-head and unconnected pile-raft systems relative to the outcropping fault rupture in the free-field is parametrically investigated,revealing different failure mechanisms.The performance of the proposed connection for protecting the pile-raft system against normal fault-induced deformations is assessed by comparing the geotechnical and structural responses of both types of foundation.The results indicate that the pocket connection can relatively reduce the cap rotation and horizontal and vertical displacements of the raft in most scenarios.The proposed connection decreases the bending moment response of the piles to their bending moment capacity,verging on a fault offset of 0.6 m at bedrock.

关键词： normal fault rupture failure mechanism pile-raft system pocket connection Finite element modeling

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