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Motion-based analysis for construction workers using biomechanical methods

Xincong YANG, Yantao YU, Heng LI, Xiaochun LUO, Fenglai WANG

《工程管理前沿(英文)》 2017年 第4卷 第1期   页码 84-91 doi: 10.15302/J-FEM-2017004

摘要: Sustaining awkward postures and overexertion are common factors in construction industry that result in work-related injuries of workers. To address there safety and health issues, conventional observational methods on the external causes are tedious and subjective, while the direct measurement on the internal causes is intrusive leading to productivity reduction. Therefore, it is essential to construct an effective approach that maps the external and internal causes to realize the non-intrusive identification of safety and health risks. This research proposes a theoretical method to analyze the postures tracked by videos with biomechanical models. Through the biomechanical skeleton representation of human body, the workload and joint torques are rapidly and accurately evaluated based on the rotation angles of joints. The method is then demonstrated by two case studies about (1) plastering and (2) carrying. The experiment results illustrate the changing intramuscular torques across the construction activities in essence, validating the proposed approach to be effective in theory.

关键词: biomechanical method     motion-based analysis     construction worker     muscular torques     workload    

生物机械工程研究进展

王裕清

《中国工程科学》 2005年 第7卷 第11期   页码 12-16

摘要:

论述了生物机械工程的重要意义、研究现状、发展趋势、存在问题及对策,旨在推动我国生物机械工程的研究和学术地位的确立,推动生物医学工程学的进步,提高人民的健康水平。

关键词: 生物机械     生物机械工程学     研究进展    

Harvesting biomechanical energy in the walking by shoe based on liquid metal magnetohydrodynamics

Dan DAI, Jing LIU, Yixin ZHOU

《能源前沿(英文)》 2012年 第6卷 第2期   页码 112-121 doi: 10.1007/s11708-012-0186-x

摘要: A liquid metal magnetohydrodynamics generation system (LMMGS) was proposed and demonstrated in this paper for collecting parasitic power in shoe while walking. Unlike the conventional shoe-mounted human power harvesters that use solid coil and gear mechanism, the proposed system employs liquid metal (Ga In Sn ) as energy carrier, where no moving part is requested in magnetohydrodynamics generators (MHGs). While walking with the LMMGS, the foot alternately presses the two liquid metal pumps (LMPs) which are respectively placed in the front and rear of the sole. As a result, the liquid metal in the LMPs (LMP I and II) is extruded and flows through the MHGs (MHG I and II) in which electricity is produced. For a comparison, three types of LMMGSs (LMMGS A, B and C) were built where all the parts are the same except for the LMPs. Furthermore, performances of these LMMGSs with different volume of injected liquid metal were tested respectively. Experimental results reveal that both the output voltage and power of the LMMGS increase with the volume of injected liquid metal and the size of the LMPs. In addition, a maximum output power of 80 mW is obtained by the LMMGS C with an efficiency of approximately 1.3%. Given its advantages of no side effect, light weight, small size and reliability, The LMMGS is well-suited for powering the wearable and implantable micro/nano device, such as wearable sensors, drug pumps and so on.

关键词: human energy harvesting     liquid metal     wearable magnetohydrodynamics generator     parasitic power in shoe    

基于人体髋关节转动中心分析的髋关节外骨骼仿生设计 Article

Wei YANG,Can-jun YANG,Ting XU

《信息与电子工程前沿(英文)》 2016年 第17卷 第8期   页码 792-802 doi: 10.1631/FITEE.1500286

摘要: 为了改善外骨骼穿戴舒适性,本文提出了一种基于人机物理交互优化的外骨骼设计方法。该方法通过设计外骨骼髋关节,使其保证人体髋关节运动时外骨骼髋关节转动中心能跟随人体髋关节转动中心的运动轨迹。当人体髋关节运动时,通过实验测量和计算可以得到其转动中心轨迹。本文设计的外骨骼髋关节运动机构能在人体髋关节屈曲/伸展和外展/内收时,保证转动中心都能够包容人体髋关节转动中心运动范围。同时,所设计的外骨骼髋关节被应用到下肢步行康复训练外骨骼中。通过人机接触力实验可知,与传统设计外骨骼髋关节进行相比,本文设计的仿生髋关节外骨骼在髋关节屈曲/伸展和内收/外展时分别可以减小24.1%和76.0%的人机接触力。这一结果证明仿生设计髋关节外骨骼更具穿戴舒适性,更符合人机工程学的设计要求。最后,本文通过建立人机闭式链模型进一步分析了仿生设计对于人体髋关节内力的影响,并验证该设计能减少关节内力作用。

关键词: 髋关节外骨骼;髋关节中心;柔顺关节;人机交互力    

增材制造技术在假肢矫形器领域的应用 Review

王岩, 谭启涛, 蒲放, David Boone, 张明

《工程(英文)》 2020年 第6卷 第11期   页码 1258-1266 doi: 10.1016/j.eng.2020.07.019

摘要:

假肢和矫形器是常见的用以代偿或补偿机体障碍人士功能需求的辅助设备。假肢矫形器的传统制造方法是一个耗时且劳动密集的过程,并存在严重的材料浪费问题。这些问题随着增材制造(AM)技术的发展和应用迎刃而解。人们已经进行了大量的理论和实践尝试,但将该技术真正用以制造假肢矫形器并满足临床需要还存在很大挑战。现存的挑战之一是缺乏一个集成AM技术和操作过程的系统框架。另外,如何基于该技术设计出同时满足功能性和舒适性需求的产品也是待解决的问题。本研究回顾了AM技术在制造假肢矫形器方面的应用现状,并对基于计算分析的产品优化设计方法和生物力学评估做了讨论。我们还设计了一个系统框架,该框架融合了从目标肢体的医学影像扫描到高适配性能产品的全过程。该过程还包含了用有限元方法进行产品优化设计和生物力学评估的环节。一个完善的系统框架能够高效地制造出满足生物力学性能需求的产品,从而大大促进AM技术在假肢矫形器领域中的应用。

关键词: 增材制造     肌肉骨骼系统生物力学     计算模型     假肢矫形器     3D打印    

Comparison of shallow tunneling method with pile and rib method for construction of subway station in

Sina AMIRI; Ali Naghi DEHGHAN

《结构与土木工程前沿(英文)》 2022年 第16卷 第6期   页码 704-717 doi: 10.1007/s11709-021-0746-4

摘要: In the present study, a comparison between the new shallow tunneling method (STM) and the traditional pile and rib method (PRM) was conducted to excavate and construct subway stations in the geological conditions of Tehran. First, by selecting Station Z6 located in the Tehran Subway Line 6 as a case study, the construction process was analyzed by PRM. The maximum ground settlement of 29.84 mm obtained from this method was related to the station axis, and it was within the allowable settlement limit of 30 mm. The acceptable agreement between the results of numerical modeling and instrumentation data indicated the confirmation and accuracy of the excavation and construction process of Station Z6 by PRM. In the next stage, based on the numerical model validated by instrumentation data, the value of the ground surface settlement was investigated during the station excavation and construction by STM. The results obtained from STM showed a significant reduction in the ground surface settlement compared to PRM. The maximum settlement obtained from STM was 6.09 mm as related to the front of the excavation face. Also, the sensitivity analysis results denoted that in addition to controlling the surface settlement by STM, it is possible to optimize some critical geometric parameters of the support system during the station excavation and construction.

关键词: shallow tunneling method     pile and rib method     ground surface settlement     subway station construction     numerical modeling    

Development of a new method for RMR and Q classification method to optimize support system in tunneling

Asghar RAHMATI,Lohrasb FARAMARZI,Manouchehr SANEI

《结构与土木工程前沿(英文)》 2014年 第8卷 第4期   页码 448-455 doi: 10.1007/s11709-014-0262-x

摘要: Rock mass classification system is very suitable for various engineering design and stability analysis. classification method is confirmed by Japan Highway Public Corporation that this method can figure out either strength or deformability of rock mass, further appropriating the amount of rock bolts, thickness of shotcrete, and size of pitch of steel ribs just after the blasting procedure. Based on these advantages of method, in this study, according to data of five deep and long tunnels in Iran, two equations for estimating the value of method from and classification systems were developed. These equations as a new method were able to optimize the support system for and classification systems. From classification and its application in these case studies, it is pointed out that the method for the design of support systems in underground working is more reliable than the and classification systems.

关键词: JH classification     Q and RMR classification     new method    

Independent cover meshless particle method for complex geotechnical engineering

Jianqiu WU, Yongchang CAI

《结构与土木工程前沿(英文)》 2018年 第12卷 第4期   页码 515-526 doi: 10.1007/s11709-017-0428-4

摘要: A new Independent Cover Meshless Particle (ICMP) method is proposed for the analysis of complex geotechnical engineering. In the ICMP method, the independent rectangular cover regardless of the shape of the analysis model is employed as the influence domain of each discrete node, the general polynomial is employed as the meshless interpolation function of the independent nodal cover, and the Cartesian Transformation Method (CTM) is used for the numerical integration of the nodal covers cut by material interfaces, joints, cracks and faults. The present method has a simple formulation and a low computational cost, and is easy for the numerical analysis and modeling of complex geotechnical engineering. Several typical numerical examples are presented to demonstrate the accuracy and robustness of the proposed method.

关键词: meshless method     particle method     independent cover     CTM     geotechnical engineering    

3D mode discrete element method with the elastoplastic model

Wei HU, Feng JIN, Chong ZHANG, Jinting WANG

《结构与土木工程前沿(英文)》 2012年 第6卷 第1期   页码 57-68 doi: 10.1007/s11709-012-0139-9

摘要: The three-dimensional mode-deformable discrete element method (3MDEM) is an extended distinct element approach under the assumptions of small strain, finite displacement, and finite rotation of blocks. The deformation of blocks is expressed by the combination of the deformation modes in 3MDEM. In this paper, the elastoplastic constitutive relationship of blocks is implemented on the 3MDEM platform to simulate the integrated process from elasticity to plasticity and finally to fracture. To overcome the shortcomings of the conventional criterion for contact fracturing, a new criterion based on plastic strain is introduced. This approach is verified by two numerical examples. Finally, a cantilever beam is simulated as a comprehensive case study, which went through elastic, elastoplastic, and discontinuous fracture stages.

关键词: mode discrete element method     elastoplastic     numerical method     discontinuum     contact    

The smoothed finite element method (S-FEM): A framework for the design of numerical models for desired

Gui-Rong Liu

《结构与土木工程前沿(英文)》 2019年 第13卷 第2期   页码 456-477 doi: 10.1007/s11709-019-0519-5

摘要:

The smoothed finite element method (S-FEM) was originated by G R Liu by combining some meshfree techniques with the well-established standard finite element method (FEM). It has a family of models carefully designed with innovative types of smoothing domains. These models are found having a number of important and theoretically profound properties. This article first provides a concise and easy-to-follow presentation of key formulations used in the S-FEM. A number of important properties and unique features of S-FEM models are discussed in detail, including 1) theoretically proven softening effects; 2) upper-bound solutions; 3) accurate solutions and higher convergence rates; 4) insensitivity to mesh distortion; 5) Jacobian-free; 6) volumetric-locking-free; and most importantly 7) working well with triangular and tetrahedral meshes that can be automatically generated. The S-FEM is thus ideal for automation in computations and adaptive analyses, and hence has profound impact on AI-assisted modeling and simulation. Most importantly, one can now purposely design an S-FEM model to obtain solutions with special properties as wish, meaning that S-FEM offers a framework for design numerical models with desired properties. This novel concept of numerical model on-demand may drastically change the landscape of modeling and simulation. Future directions of research are also provided.

关键词: computational method     finite element method     smoothed finite element method     strain smoothing technique     smoothing domain     weakened weak form     solid mechanics     softening effect     upper bound solution    

Explicit optimization method for cutting-screw-thread on the basis of dual-RSM

Zhengbao LEI, Shubin WEI, Qingyun DU

《机械工程前沿(英文)》 2010年 第5卷 第4期   页码 423-430 doi: 10.1007/s11465-010-0109-7

摘要: To obtain the explicit function for optimizing the cutting-screw-thread (CST) in crash, the simulations of frontal crash at the speed of 56 km/h have been carried out in VPG. The peak acceleration in crash has been taken as the evaluation index of energy absorption characteristics. First, the single factor experiment was taken based on six parameters affecting on the absorption characteristics of CST. Second, the peak acceleration function of each parameter by using response surface method (RSM) is obtained. Third, the explicit resultant peak acceleration function of six parameters by using RSM again is obtained. A dual RSM-based explicit method is proposed. According to this function, the best size dimensions of CST in different crash conditions could be easily obtained. Finally, an example shows that the values of the calculation errors for simulation value and target value (40 g) are 3.6% and 1.3%, respectively. This method can satisfy the demand for engineering accuracy.

关键词: vehicle engineering     crash     safety     explicit method     response surface method    

Unified method for typical gear failure modeling and stiffness calculation based on the matrix equation

《机械工程前沿(英文)》 2024年 第19卷 第3期 doi: 10.1007/s11465-024-0794-2

摘要: The failure types in gear systems vary, with typical ones mainly including pitting, cracking, wear, and broken teeth. Different modeling and stiffness calculation methods have been developed for various gear failure types. A unified method for typical gear failure modeling and stiffness calculation is introduced in this study by considering the deviations in the time-varying meshing stiffness (TVMS) of faulty gears resulting from the use of different methods. Specifically, a gear tooth is discretized into a large number of microelements expressed with a matrix, and unified models of typical gear failures are built by adjusting the values of the matrix microelements. The values and positions of the microelements in the tooth failure model matrix have the same physical meaning as the parameter variables in the potential energy method (PEM), so the matrix-based failure model can be perfectly matched with PEM. Afterward, a unified method for TVMS is established. Modeling of healthy and faulty gears with pitting, wear, crack, and broken tooth is performed with the matrix equation, and the corresponding TVMS values are calculated by incorporating the matrix models with PEM. On the basis of the results, the mechanism of typical fault types that affect TVMS is analyzed, and the conclusions are verified through the finite element method. The developed unified method is a promising technique for studying the dynamic response characteristics of gear systems with different failure types because of its superiority in eliminating stiffness deviations.

关键词: gears     matrix equation     failure modeling     TVMS calculation     unified method    

Application of random set method in a deep excavation: based on a case study in Tehran cemented alluvium

Arash SEKHAVATIAN, Asskar Janalizadeh CHOOBBASTI

《结构与土木工程前沿(英文)》 2019年 第13卷 第1期   页码 66-80 doi: 10.1007/s11709-018-0461-y

摘要: The design of high-rise buildings often necessitates ground excavation, where buildings are in close proximity to the construction, thus there is a potential for damage to these structures. This paper studies an efficient user-friendly framework for dealing with uncertainties in a deep excavation in layers of cemented coarse grained soil located in Tehran, Iran by non-deterministic Random Set (RS) method. In order to enhance the acceptability of the method among engineers, a pertinent code was written in FISH language of FLAC2D software which enables the designers to run all simulations simultaneously, without cumbersome procedure of changing input variables in every individual analysis. This could drastically decrease the computational effort and cost imposed to the project, which is of great importance especially to the owners. The results are presented in terms of probability of occurrence and most likely values of the horizontal displacement at top of the wall at every stage of construction. Moreover, a methodology for assessing the credibility of the uncertainty model is presented using a quality indicator. It was concluded that performing RS analysis before the beginning of every stage could cause great economical savings, while improving the safety of the project.

关键词: uncertainty     reliability analysis     deep excavations     random set method     finite difference method    

A simple method for evaluating liquefaction potential from shear wave velocity

Lianyang ZHANG,

《结构与土木工程前沿(英文)》 2010年 第4卷 第2期   页码 178-195 doi: 10.1007/s11709-010-0023-4

摘要: The simplified procedure using shear wave velocity measurements is increasingly used to evaluate the seismic liquefaction potential of soils. This procedure is based on finding the boundary separating the liquefaction and non-liquefaction cases through the analysis of liquefaction case histories, following the general format of the Seed-Idriss simplified procedure based on standard penetration test (SPT) data. It is noted that many assumptions have been made in the simplified procedure. This paper develops a simple method for evaluating the liquefaction potential of soils from shear wave velocity by using the optimum seeking method to directly analyze the liquefaction history data and quantify the influence of major factors affecting the liquefactions potential of soils. The factors considered are the earthquake magnitude, the vertical effective overburden stress, the shear wave velocity, the peak acceleration at the ground surface of the site, and the fines content of the soil. The most important factor has been identified as the shear wave velocity. The developed method uses the measured data directly and in a very simple way. Neither stress-correction of shear wave velocity nor calculation of cyclic shear stress as in the simplified procedure is required. Comparisons indicate that the developed simple method has a higher success rate for evaluating liquefaction potential of soils than the simplified procedure. A case study is presented to illustrate the application of the developed simple method and further confirms its accuracy.

关键词: liquefaction     earthquake     simple method     shear wave velocity     case history introduction    

A new method for boring of non-circular holes

ZHANG Kai, HU De-jin

《机械工程前沿(英文)》 2006年 第1卷 第4期   页码 456-460 doi: 10.1007/s11465-006-0058-3

摘要: A revolving electromagnetic actuation mechanism composed of an electromagnetic stator and an electromagnetic rotor has been developed for boring non-circular holes. The main component of the rotor is a flexure-hinged based flexible body. There are four pole-pair coils in the stator supplying actuation currents. The micro-displacement between the stator and rotor can be controlled by changing the currents applied in the pole-pair coils. Through linearization of the actuation force near the static action point, a linear relationship between the control current and the actuation force was established, and the synchronizing control method of the electromagnetic actuation mechanism is presented here. With two-factor analysis of the linearization error of the actuation force, the influences of control current and micro-displacement to the linearization error of the actuation force were studied. Then, the principle for designing the basic parameters of the magnetic actuation mechanism is put forward. The calibration of the mechanism indicates that the relationship between the micro-displacement of the rotor and the control current has linear characteristics in the required micro-displacement range. Simulation tests show that the turning radius of the rotor changes with the control current. The proposed mechanism can feasibly supply a controllable micro displacement to the boring bar.

关键词: electromagnetic actuation     control method     displacement     flexible body     revolving electromagnetic    

标题 作者 时间 类型 操作

Motion-based analysis for construction workers using biomechanical methods

Xincong YANG, Yantao YU, Heng LI, Xiaochun LUO, Fenglai WANG

期刊论文

生物机械工程研究进展

王裕清

期刊论文

Harvesting biomechanical energy in the walking by shoe based on liquid metal magnetohydrodynamics

Dan DAI, Jing LIU, Yixin ZHOU

期刊论文

基于人体髋关节转动中心分析的髋关节外骨骼仿生设计

Wei YANG,Can-jun YANG,Ting XU

期刊论文

增材制造技术在假肢矫形器领域的应用

王岩, 谭启涛, 蒲放, David Boone, 张明

期刊论文

Comparison of shallow tunneling method with pile and rib method for construction of subway station in

Sina AMIRI; Ali Naghi DEHGHAN

期刊论文

Development of a new method for RMR and Q classification method to optimize support system in tunneling

Asghar RAHMATI,Lohrasb FARAMARZI,Manouchehr SANEI

期刊论文

Independent cover meshless particle method for complex geotechnical engineering

Jianqiu WU, Yongchang CAI

期刊论文

3D mode discrete element method with the elastoplastic model

Wei HU, Feng JIN, Chong ZHANG, Jinting WANG

期刊论文

The smoothed finite element method (S-FEM): A framework for the design of numerical models for desired

Gui-Rong Liu

期刊论文

Explicit optimization method for cutting-screw-thread on the basis of dual-RSM

Zhengbao LEI, Shubin WEI, Qingyun DU

期刊论文

Unified method for typical gear failure modeling and stiffness calculation based on the matrix equation

期刊论文

Application of random set method in a deep excavation: based on a case study in Tehran cemented alluvium

Arash SEKHAVATIAN, Asskar Janalizadeh CHOOBBASTI

期刊论文

A simple method for evaluating liquefaction potential from shear wave velocity

Lianyang ZHANG,

期刊论文

A new method for boring of non-circular holes

ZHANG Kai, HU De-jin

期刊论文