scholarly journals A weld-distortion analysis method of the shell structures using ultra structural FE model

2015 ◽  
Vol 33 (3) ◽  
pp. 62-67 ◽  
Author(s):  
Yunsok Ha ◽  
Myungsu Yi
Keyword(s):  
Shell Structures ◽  
Fe Model ◽  
Analysis Method ◽  
Distortion Analysis ◽  
Weld Distortion

scholarly journals Evaluation of the Effects of the Chincup Appliance on the Craniofacial Structures by the Finite Element Analysis

2017 ◽  
Vol 7 ◽  
pp. 219-223
Author(s):  
Beril Demir Karamanli ◽  
Hülya Kılıçoğlu ◽  
Armagan Fatih Karamanli
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Fe Model ◽  
Analysis Method ◽  
Class Iii ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Clinical Changes

Aims The aim of this study is to evaluate the effects of the chincup appliance used in the treatment of Class III malocclusions, not only on the mandible or temporomandibular joint (TMJ) but also on all the craniofacial structures. Materials and Methods Chincup simulation was performed on a three-dimensional finite element (FE) model. 1000 g (500 g per side) force was applied in the direction of chin-condyle head. Nonlinear FE analysis was used as the numerical analysis method. Results By the application of chincup, stresses were distributed not only on TMJ or mandible but also on the circummaxillary sutures and other craniofacial structures. Conclusions Clinical changes obtained by chincup treatment in Class III malocclusions are not limited by only mandible. It was seen that also further structures were affected.

scholarly journals Risks of Ear Complaints of Passengers and Drivers While Trains Are Passing Through Tunnels at High Speed: A Numerical Simulation and Experimental Study

2019 ◽  
Vol 16 (7) ◽  
pp. 1283 ◽  
Author(s):  
Pengpeng Xie ◽  
Yong Peng ◽  
Tiantian Wang ◽  
Honghao Zhang
Keyword(s):  
High Speed ◽  
Fe Model ◽  
Analysis Method ◽  
High Speed Train ◽  
Pressure Transients ◽  
Operation Speed ◽  
High Speed Trains ◽  
Recorded Data ◽  
Four Levels ◽  
Human Middle Ear

Ear complaints induced by interior pressure transients are common experiences for passengers and crew members when high-speed trains are passing through tunnels. However, approaches to assessing the risks of the pressure-related aural discomfort have not been reported until recently. The objective of this study was to evaluate the hazards of interior pressure transients of high-speed train on human ears combining the effects of operation speed and seal index. Moving model tests were conducted to obtain the pressure transients when the model train runs in the tunnel. The recorded data were transformed into the interior pressures by empirical formula. Furthermore, the aural sensations were divided into four levels hierarchically and the range for each level was derived by logistic regression analysis method and represented by three biomechanical metrics. Furthermore, a human middle ear finite element (FE) model was used to simulate its dynamics under the interior pressures. The results indicate that lifting operation speed from 250 km/h to 350 km/h in tunnel will prolong the duration of ear complaints by more than two times whereas improving the seal index from 4 s to 12 s will reduce the incidences of the onset of tinnitus and hearing loss by more than ten times. In addition, the duration of aural comfort shortens from the head car to the tail car against the running direction. It is desirable that enhancing the seal index improve the aural sensations of the passengers and crew members considering the lifting operation speed of high-speed train.

scholarly journals Transfer Path Analysis and Contribution Evaluation Using SVD- and PCA-Based Operational Transfer Path Analysis

2020 ◽  
Vol 2020 ◽  
pp. 1-23
Author(s):  
Wei Cheng ◽  
Diane Blamaud ◽  
Yapeng Chu ◽  
Lei Meng ◽  
Jingbai Lu ◽  
...  
Keyword(s):  
Path Analysis ◽  
Principal Component ◽  
Structure Design ◽  
Shell Structures ◽  
Analysis Method ◽  
Transfer Path ◽  
Frequency Components ◽  
Transfer Path Analysis ◽  
Value Decomposition ◽  
Traditional Counterpart

To quantitatively identify the transfer paths and evaluate path contributions of shell structures, an singular value decomposition- (SVD-) and principal component analysis- (PCA-) based operational transfer path analysis method is constructed and studied in this paper. Firstly, SVD is used to determine the contribution of each path and reduce crosstalk. Secondly, PCA is applied to reduce the influence of unwanted frequency components and thus reduce noises. This allows the presented OTPA to be more accurate than its traditional counterpart. Once the transmissibility function is obtained, the response synthesis is determined, and the transfer path analysis and path contribution evaluation can be effectively carried out. Numerical and experimental case studies are carried out to validate and test the performance of the presented method. Furthermore, a comprehensive observing the influences of correlation between sources and distance of sources and receiver is also provided. Generally, this paper provides accurate transfer path analysis and path contributions for mechanical systems, which can benefit vibration and noise monitoring and reduction through vibration reduction structure design for new equipment or vibration damping on the major vibration transfer paths for current equipment.

Simulation of Bus Ride Comfort under the Excitation of Road Irregularity

2012 ◽  
Vol 510 ◽  
pp. 249-254 ◽  
Author(s):  
Jin Feng ◽  
Yuan Hua Chen
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Ride Comfort ◽  
Temporal Frequency ◽  
Vertical Vibration ◽  
Fe Model ◽  
Analysis Method ◽  
The Road ◽  
Power Spectral ◽  
Bus Structure

Bus vibration is studied by the finite element method (FEM) base on bus structure model. The bus mathematical model of vertical vibration is established and the vibration response variables were deduced with the modal analysis method. The finite element (FE) model is established and decoupled. The transformational relation between spatial frequency displacement power spectral density (PSD) and temporal frequency displacement PSD and the sampling characteristics of the road irregularity PSD in numerical computation are discussed. Road irregularity load is modeled in software. The FE model is solved using modal analysis method and the acceleration PSD of each keypoint can be gained. Finally, a road test experiment is carried on to verify the simulation results. The example indicated that study on vehicle ride comford by FEM has instructive meaning.

Development of Welding Distortion Analysis Method Using Residual Strain as Boundary Condition

2008 ◽  
Vol 580-582 ◽  
pp. 649-654 ◽  
Author(s):  
Yun Sok Ha ◽  
Si Hoon Cho ◽  
Tae Won Jang
Keyword(s):  
Boundary Condition ◽  
Boundary Conditions ◽  
Residual Strain ◽  
The Other ◽  
Welding Distortion ◽  
Thermal Distortion ◽  
Analysis Method ◽  
Distortion Analysis ◽  
Direct Input ◽  
Inherent Strain

There are two ways of conventional thermal distortion analysis. One is thermal elastoplastic analysis and the other is equivalent forces method based on inherent strain. The former needs exorbitant analysis time, while the latter cannot obtain stress results and requires more time with loads modeling on curved plates. To solve those time-consuming problems, a new kind of thermal distortion analysis method was developed. In this method, inherent strains are devised to be used as direct input factors as boundary conditions. Suggested analysis method was already adopted at welding distortion analysis of large hull block, which was considered as impossible.

Dynamic Instability of a Cylindrical Shell Structure Subjected to Horizontal and Vertical Excitations Simultaneously

2004 ◽  
Author(s):  
Katsuhisa Fujita ◽  
Taisuke Nosaka ◽  
Tomohiro Ito
Keyword(s):  
Cylindrical Shell ◽  
Dynamic Stability ◽  
Parametric Excitation ◽  
Dynamic Instability ◽  
Simulation Analysis ◽  
Seismic Analysis ◽  
Shell Structures ◽  
Analysis Method ◽  
Water Tanks ◽  
Vertical Excitations

Many structures such as support columns such as those for elevated expressways and towers tend to become larger and more flexible recently, thus the buckling or collapse of these structures is considered to easily occur than ever due to huge earthquakes. Actually, in the Hyogo-ken Nambu earthquake in Japan, buckling phenomena of tall support columns were observed every-where. Therefore, the evaluation technology on the dynamic stability is very important in order to ensure the seismic design reliability for these structures. The authors have ever studied the effects of the horizontal and vertical simultaneous excitations on the above-mentioned buckling phenomena of support columns experimentally. More-over, they also investigated the fundamental phenomena of the dynamic stability of the support columns subjected to the horizontal and vertical excitations simultaneously by numerical simulations using an analytical model where the support column is treated as a tall elastic cantilever beam. The purpose of this paper is on the dynamic instability, that is dynamic buckling, of a cylindrical shell structures such as those for elevated expressways, towers, containment vessels, LNG tanks and water tanks in various industrial plants so on subjected to horizontal and vertical excitations simultaneously. The coupled motion of equation with horizontal and vertical excitations simultaneously for these cylindrical shell structures is derived in this paper, and this modeling is shown to become a Mathieu type’s parametric excitation. The numerical simulation analysis is carried out for a cylindrical shell model with an attached mass on its tip. Comparing with the classical seismic analysis method, this proposed dynamic instability analysis method shows the larger deformation in horizontal direction due to the parametric excitation of the vertical seismic wave. As the results, the structures are apt to lose the structural stability more due to the coupling effects between the horizontal and vertical seismic simultaneous loadings.

Safety Analysis on the Variable Constraint Space Reticulated Shell Structures

2011 ◽  
Vol 368-373 ◽  
pp. 1613-1616
Author(s):  
Xiu Li Wang ◽  
En Ping Jin ◽  
Yan Peng Zhu
Keyword(s):  
Shell Structure ◽  
Reference Value ◽  
Shell Structures ◽  
Optimized Design ◽  
Quality And Safety ◽  
Analysis Method ◽  
Long Span ◽  
Temporary Support ◽  
Multiple Variable ◽  
Constraint Structure

During construction, the spatial shell structure is the variable constraint structure system. In order to guarantee the construction quality and safety, its addition or disassembly scheme of temporary support must be optimized design. Based on variable constraint structure analysis method, the paper simulated and analyzed possible multiple variable constraint scheme during the long-span space reticulated shell structural construction, and put forward the principle and method abide by addition and disassembly design of temporary support. For other variable constraint structures similar to the spatial shells, the principle and method proposed has a very great reference value.

Study on Finite Element Model of Infilled Walls of Steel Frames

2011 ◽  
Vol 250-253 ◽  
pp. 2424-2427 ◽  
Author(s):  
Xin Zhao ◽  
Mai Wu ◽  
Dan Dan Kong ◽  
Shun Wei Chen
Keyword(s):  
Finite Element ◽  
Lightweight Concrete ◽  
Steel Frames ◽  
Residential Building ◽  
Element Model ◽  
Fe Model ◽  
Analysis Method ◽  
Hysteresis Model ◽  
Theory Analysis ◽  
Comparison Theory

Autoclaved lightweight concrete (ALC) block infills are used widely for steel residential building system in China; the authors of this paper brought forward a kind of macro finite element (FE) model of ALC block infills of steel frames on the basis of experimental study. Furthermore the hysteresis model of the strut element of infill was established. At last the validity of the strut element was verified by comparison theory analysis results with experiment ones. The analysis method and theory of this paper can be applied to other kind of infills after being revised properly.

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