Finite Element Method for Kinematic Analysis of Parallel Hip Joint Manipulator

2015 ◽  
Vol 7 (4) ◽  
Author(s):  
Gang Cheng ◽  
Song-tao Wang ◽  
De-hua Yang ◽  
Jian-hua Yang

This paper presents a finite element method (FEM) for the kinematic solution of parallel manipulators (PMs), and this approach is applied to analyze the kinematics of a parallel hip joint manipulator (PHJM). The analysis and simulation results indicate that FEM can get accurate results of the kinematics of the PHJM, and the solution process shows that using FEM can solve nonlinear and linear kinematic problems in the same mathematical framework, which provides a theory base for establishing integrated model among different parameter models of the PHJM.

Author(s):  
T. R. Grimm

Abstract The importance of the finite element method as an engineering tool for design and analysis is emphasized in a senior level elective course taught at Michigan Technological University. The course emphasizes hands-on experience with computers and the pre- and post-analysis of results to establish confidence in solutions obtained. The students learn by using the finite element method to “solve” several design projects, rather than by being told about the method without significant actual experience. They also learn about the basis of the method, including formation of the matrix equations required and the numerical methods used in their solution. Intelligent use of the method requires that engineers understand both the mechanics of how to apply the method, i.e modeling requirements, and the limitations imposed by the basic solution process. The course provides the students with important experience in using the powerful finite element method as a design tool. It requires a strong background of fundamentals and stimulates the problem solving thinking skills so essential to industry.


2018 ◽  
Vol 32 (34n36) ◽  
pp. 1840073
Author(s):  
Hui Li ◽  
Yi-Bo Jiang ◽  
Jian-Wen Cai

Azimuthal electromagnetic wave logging-while-drilling (LWD) technology can detect weak electromagnetic wave signal and realize real-time resistivity imaging. It has great values to reduce drilling cost and increase drilling rate. In this paper, self-adaptive hp finite element method (FEM) has been used to study the azimuthal resistivity LWD responses in different conditions. Numerical simulation results show that amplitude attenuation and phase shift of directional electromagnetic wave signals are closely related to induced magnetic field and azimuthal angle. The peak value and polarity of geological guidance signals can be used to distinguish reservoir interface and achieve real-time geosteering drilling. Numerical simulation results also show the accuracy of the self-adaptive hp FEM and provide physical interpretation of peak value and polarity of the geological guidance signals.


2020 ◽  
Vol 12 ◽  
Author(s):  
Jue Wang ◽  
Tao Ma ◽  
Xu Wang ◽  
Fang Wang

Background: : A THz Plasmonic Waveguide Based on Graphene Coated Bow-tie Nanowire (TPW-GCBN) is proposed. The waveguide characteristics are investigated by using Finite Element Method (FEM). The influence of the geometric parameters on propagation constants, electric field distributions, effective mode areas, and propagation lengths are obtained numerically. The performance tunability of TPW-GCBN is also studied by adjusting the Fermi energy (FE). The simulation results show that the TPW-GCBN has better mode confinement ability. The TPW-GCBN has potential applications in high density integration of photonic circuit for the future tunable micro nano optoelectronic devices. Surface plasmon polaritons (SPPs) based waveguides have been widely used to enhance the local electric fields. It also has the capability of manipulating electromagnetic fields on the deep-subwavelength. Objective:: The waveguide characteristics of a THz Plasmonic Waveguide Based on Graphene Coated Bow-tie Nanowire (TPW-GCBN) should be investigated. The tunability of TPW-GCBN should be studied by adjusting the chemical potential (FE) which can be changed by the voltage. Method: : The mode analysis and parameter sweep in Finite Element Method (FEM) were used to simulate the TPW-GCBN for analyzing effective refractive index (neff), electric field distributions, normalized mode areas (Am), propagation length (Lp) and figure of merit (FoM). Results: : At 5 THz, Aeff of λ2/14812, Lp of ~2 μm and FoM of 25 can be achieved. The simulation results show that the TPW-GBN has good mode confinement ability and flexible tunability. Conclusion:: The TPW-GBN provides a new freedom to manipulate the graphene surface plasmons, and leads to new applications in high density integration of photonic circuit for tunable integrated optical devices.


2020 ◽  
Vol 32 (5) ◽  
pp. 707-724
Author(s):  
Xuzhong Su ◽  
Xinjin Liu

PurposeTensile property is one basic mechanics performance of the fabric. In general, not only the tensile values of the fabric are needed, but also the dynamic changing process under the tension is also needed. However, the dynamic tensile process cannot be included in the common testing methods by using the instruments after fabric weaving.Design/methodology/approachBy choosing the weft yarn and warp yarn in the fabric as the minimum modeling unit, 1:1 finite element model of the whole woven fabrics was built by using AutoCAD software according to the measured geometric parameters of the fabrics and mechanical parameters of yarns. Then, the fabric dynamic tensile process was simulated by using the ANSYS software. The stress–strain curve along the warp direction and shrinkage rate curve along the weft direction of the fabrics were simulated. Meanwhile, simulation results were verified by comparing to the testing results.FindingsIt is shown that there are four stages during the fabric tensile fracture process along the warp direction under the tension. The first stage is fabric elastic deformation. The second stage is fabric yield deformation, and the change rate of stress begins to slow down. The third stage is fiber breaking, and the change of stress fluctuates since the breaking time of the fibers is different. The fourth stage is fabric breaking.Originality/valueIn this paper, the dynamic tensile process of blended woven fabrics was studied by using finite element method. Although there are differences between the simulation results and experimental testing results, the overall tendency of simulation results is the same as the experimental testing results.


2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Huifen Peng ◽  
Yujie Song ◽  
Ye Xia

The cohesive zone model (CZM) has been widely used for numerical simulations of interface crack growth. However, geometrical and material discontinuities decrease the accuracy and efficiency of the CZM when based on the conventional finite element method (CFEM). In order to promote the development of numerical simulation of interfacial crack growth, a new CZM, based on the wavelet finite element method (WFEM), is presented. Some fundamental issues regarding CZM of interface crack growth of double cantilever beam (DCB) testing were studied. The simulation results were compared with the experimental and simulation results of CFEM. It was found that the new CZM had higher accuracy and efficiency in the simulation of interface crack growth. At last, the impact of crack initiation length and elastic constants of material on interface crack growth was studied based on the new CZM. These results provided a basis for reasonable structure design of composite material in engineering.


2015 ◽  
Vol 1096 ◽  
pp. 417-421
Author(s):  
Pei Luan Li ◽  
Zi Qian Huang

By the use of finite element method, this paper predicts the effects of the shapes of reinforcements with different ductility (Co) on the effective elastic response for WC-Co cemented carbide. This paper conducts a comparative study on the material properties obtained through theoretical model, numerical simulation and experimental observations. Simulation results indicate that the finite element method is more sophisticated than the theoretical prediction.


2011 ◽  
Vol 480-481 ◽  
pp. 634-638
Author(s):  
Shao Feng Zeng ◽  
Wen Zhe Chen

In this study AZ31 sheet with a thickness of 1.2mm and diameter of 52mm was simulated to press into a dish by a finite element method(FEM) software, which to obtain better processing of plastics forming of magnesium alloy by varying die parameters. In order to find the way of development on drawing property and to formulate the rational stamping processing, simulations have been applied on the maximum principal stress various with round radius of dent die and round radius of punch and die gap. Simulation results show that: to obtain a dish of 29mm diameter, a sheet of AZ31 magnesium with a thickness of 1.2mm and diameter of 52mm has been drawn, the fracture occurring at the corner of dish wall bottom. the ability of drawing varies with the round radius of dent die, which better radius is 3.8 mm. In the same way better round radius of punch is 3.0 mm, while better half gap is 1.8mm. Experiments also show that high diameter ratio has been increased with the various of die parameters and forming ability of material has been developed. It is reliable of simulation of finite element method.


2013 ◽  
Vol 416-417 ◽  
pp. 287-292
Author(s):  
Qiang Liu ◽  
Hai Tao Yu ◽  
Jia Dong Zhu ◽  
Shi Ui Zhou ◽  
Chun Yuan Liu

A double-sided linear flux-switching permanent magnet machine applied in marine rudder direct drive applications is presented. The starting performances of the machine are calculated by finite element method. The simulation results of the proposed DLFSPM are verified by the experiment. The results have verified that the machine is suitability marine rudder direct drive applications.


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