Analysis of Torsion Stiffness of Flexible Pivot Bearing with Radial Array Rectangular Section

2013 ◽  
Vol 584 ◽  
pp. 214-219
Author(s):  
Chun Jie Liu ◽  
X.Q. Wu ◽  
W.M. Gan ◽  
Zhi Wei Chen
Keyword(s):  
Finite Element ◽  
Angular Displacement ◽  
Element Model ◽  
Simulation Method ◽  
Limited Range ◽  
Rectangular Section ◽  
Performance Specification ◽  
Pivot Bearing ◽  
The Difference ◽  
Torsion Stiffness

Flexible pivot bearing, a kind of precision elastic components, can provide necessary angular displacement within limited range. The torsion stiffness of the bearing, as the most important performance specification, is studied in the paper. The analytical expression (for array numberNand) of the torsion stiffness of the flexible pivot bearing with rectangular section is deduced by using static equilibrium theory. The constituent parts and physical meaning of the expression are discussed. The accuracy and applicability of the deduced expression are investigated in comparison with other equations in references. A finite element model is built accurately. Simulation of the flexible bearing (N=4) is carried out to compare the FEM solution with that obtained by the derived expression. The results show that the deduced equation is applicable to allNradial array flexible pivot bearing with rectangular section, and the difference of the stiffness value is about 7% comparing with that calculated by simulation method.

scholarly journals Analysis of Vertical Stiffness of Air Spring Based on Finite Element Method

2018 ◽  
Vol 153 ◽  
pp. 06006
Author(s):  
Jiatong Ye ◽  
Hua Huang ◽  
Chenchen He ◽  
Guangyuan Liu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Finite Element Simulation ◽  
Element Model ◽  
Simulation Method ◽  
Bench Test ◽  
Air Spring ◽  
Vertical Stiffness ◽  
Element Simulation ◽  
Element Method

In this paper, a finite element model of membrane air spring in the vehicle is established, and its vertical stiffness characteristics under a certain inflation pressure are analysed. The result of finite element simulation method is compared with the result of the air spring bench test. The accuracy and reliability of the finite element simulation method in nonlinear analysis of air spring system are verified. In addition, according to the finite element method, the influence of the installation of the air spring limit sleeve on its stiffness is verified.

Growth Behavior of Two Interacting Surface Cracks of Dissimilar Size (Comparison for Tensile and Bending Load)

2010 ◽  
Author(s):  
Masayuki Kamaya ◽  
Masanori Kikuchi ◽  
Eiichi Miyokawa
Keyword(s):  
Finite Element ◽  
Element Model ◽  
Growth Behavior ◽  
Multiple Cracks ◽  
Surface Cracks ◽  
Element Mesh ◽  
Loading Direction ◽  
Parallel Surface ◽  
Bending Load ◽  
The Difference

When multiple cracks approach one another, the stress intensity factor is likely to change due to the interaction of the stress field. This causes change in growth rate and shape of cracks. In particular, when cracks are in parallel position to the loading direction, the shape of cracks becomes non-planar. In this study, the complex growth of interacting cracks is evaluated by using the S-Version finite element method, in which local detailed finite element mesh (local mesh) is superposed on cores finite element model (global mesh) representing the global structure. In this study, two parallel surface cracks are subjected to two types of loading; tensile and bending load. Comparisons are made on the growth behavior under two types of loading. It is shown that the smaller crack stop growing due to the interaction when the difference in size of two cracks is large. This tendency is more significant for the bending load. The procedure for evaluating crack growth for Fitness-for-Service assessment is discussed.

The Sardinia Radio Telescope: A comparison between close-range photogrammetry and finite element models

2015 ◽  
Vol 22 (5) ◽  
pp. 1005-1026 ◽  
Author(s):  
Franco Buffa ◽  
Andrea Causin ◽  
Antonio Cazzani ◽  
Sergio Poppi ◽  
Giannina Sanna ◽  
...  
Keyword(s):  
Finite Element ◽  
Radio Telescope ◽  
Active Surface ◽  
Element Model ◽  
Wind Pressure ◽  
Primary Mirror ◽  
Actual Surface ◽  
Close Range Photogrammetry ◽  
Close Range ◽  
The Difference

The Sardinia Radio Telescope (SRT), located near Cagliari (Italy), is the world’s second largest fully steerable radio telescope endowed with an active-surface system. Its primary mirror has a quasi-parabolic shape with a diameter of 64 m. The configuration of the primary mirror surface can be modified by means of electro-mechanical actuators. This capability ensures, within a fixed range, the balancing of the deformation caused, for example, by loads such as self-weight, thermal effects and wind pressure. In this way, the difference between the ideal shape of the mirror (which maximizes its performances) and the actual surface can be reduced. In this paper the authors describe the characteristics of the SRT, the close-range photogrammetry (CRP) survey developed in order to set up the actuator displacements, and a finite element model capable of accurately estimating the structural deformations. Numerical results are compared with CRP measurements in order to test the accuracy of the model.

scholarly journals Finite Element Modeling and Mechanical Behavior of Masonry-Infilled RC Frame

2016 ◽  
Vol 10 (1) ◽  
pp. 76-92
Author(s):  
Hongyu Deng ◽  
Baitao Sun
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Element Model ◽  
Simulation Method ◽  
Shear Resistance ◽  
Calculation Formula ◽  
Infill Wall ◽  
Seismic Code ◽  
Element Modeling ◽  
Contact Position

During the analysis of reinforced concrete structures, the infill wall is usually simplified as a diagonal inclined strut to facilitate finite element modeling calculations. However, the actual seismic damage and single frame-filled wall pushover experimental results show that when the earthquake shear force is huge, the top of the infill wall and the beam–column connections are usually, thus the path of the force transfer will be changed. Based on this actual failure phenomenon, a new calculation model which has different contact position between the equivalent bracing walls and the frame columns is generated. Thus, the force analysis is given based on this model, the formulae for calculating the equivalent width of bracing walls, the shear bearing capacity of the wall-filled frame, and the infill wall’s actual participation in the stiffness. A finite element simulation method by ABAQUS is used to determine an empirical formula for calculating the reasonable contact position between the equivalent bracing walls and the frame columns. The verification results show that the finite element model presented in this paper is more reasonable, and the stiffness and shear resistance of infill wall should not be neglected. The calculation formula of stiffness of infill wall presented in this paper is coincided with seismic code. But the calculation formula of shear resistance of infill wall presented in seismic code is higher than the actual value, so it is suggested that calculation formula presented in this paper should be accepted.

Investigation of Broken Cut Spikes on Elastic Fastener Tie Plates Using an Integrated Simulation Method

2018 ◽  
Author(s):  
Yin Gao ◽  
Mike McHenry ◽  
Brad Kerchof
Keyword(s):  
Finite Element ◽  
Element Model ◽  
Simulation Method ◽  
Operating Conditions ◽  
Analysis Model ◽  
Element Analysis ◽  
Integrated Simulation ◽  
Multibody Model ◽  
Track System ◽  
High Degree

Cut spike fasteners, used with conventional AREMA rolled tie plates and solid sawn timber ties, are the most common tie and fastener system used on North American freight railroads. Cut spikes are also used to restrain tie plates that incorporate an elastic rail fastener — that is, an elastic clip that fastens the rail to the tie plate. Elastic fasteners have been shown to reduce gage widening and decrease the potential for rail roll compared to cut spike-only systems. For this reason, elastic fastener systems have been installed in high degree curves on many railroads. Recent observations on one Class I railroad have noted broken cut spikes when used with these types of tie plates in mountainous, high degree curve territory. Broken screw spikes and drive spikes on similar style plates have also been observed. In this paper, a simulation method that integrates a vehicle-track system dynamics model, NUCARS®, with a finite element analysis model is used to investigate the root causes of the broken spikes. The NUCARS model consists of a detailed multibody train, wheel-rail contact parameters, and track model that can estimate the dynamic loading environment of the fastening system. For operating conditions in tangent and curve track, this loading environment is then replicated in a finite element model of the track structure — ties, tie plates, and cut spikes. The stress contours of the cut spikes generated in these simulations are compared to how cut spikes have failed in revenue service. The tuning and characterization of both the vehicle dynamics multibody model and the finite element models are presented. Additionally, the application of this approach to other types of fastening systems and spike types is discussed. Preliminary results have identified a mechanism involving the dynamic unloading of the tie plate-to-tie interface due to rail uplift ahead of the wheel and the resulting transfer of net longitudinal and lateral forces into the cut spikes. Continued analysis will attempt to confirm this mechanism and will focus on the severity of these stresses, the effect of increased grade, longitudinal train dynamics, braking forces, and curvature.

scholarly journals Numerical Simulation of The Response of An Underground Pipeline Connector With a Super-Large Section Under Complex Geological Conditions

2021 ◽  
Author(s):  
Long Ma ◽  
Ping Ai ◽  
ChuanSheng Xiong
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Simulation Method ◽  
Large Section ◽  
Simulation Accuracy ◽  
Numerical Simulation Method ◽  
Geological Conditions ◽  
The Finite Element Model

Abstract Aiming at the low simulation accuracy of the numerical simulation method of the joint response of the super-large section underground comprehensive pipeline gallery under the current complicated geological conditions, a numerical simulation method of the joint response of the super-large section underground comprehensive pipe gallery joint response under the complicated geological conditions based on the finite element model was proposed. According to the analysis process for the super-large section underground comprehensive pipe gallery, the viscous boundary of the comprehensive pipe gallery is determined. Additionally, by analyzing soil and structural parameters, the optimal combined dynamic boundary is used as the model boundary. The HSS model is used to describe the constitutive structure of the soil, and by improving the Goodman element to describe the contact surface of the model, the finite element model of the joint response of the comprehensive pipe gallery is constructed. Furthermore, based on the internal force balance and deformation coordination conditions, considering the influence of the deformation shape of the joint joints and the elongation of the prestressed tendons on the finite element model, the response model of the integrated pipe gallery joint is optimized. Experimental results show that the proposed method has higher numerical simulation accuracy.

scholarly journals Effect of Torsional Element towards High-Speed Rotating Shaft’s Critical Speed at Different Boundary Conditions

2019 ◽  
Vol 8 (4) ◽  
pp. 6787-6792
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
High Speed ◽  
Critical Speed ◽  
Element Model ◽  
Accurate Estimation ◽  
Fe Model ◽  
Rotating Shaft ◽  
Different Boundary Conditions ◽  
The Difference

Efficiency improvement that can be provided by the high-speed rotating equipment becomes a concern for designers nowadays. Since the high-speed rotating machinery was capable of rotating at very near to critical speed, the accurate estimation of critical speed needs to be considered. This paper investigated the effect of torsional element towards critical speed of high-speed rotating shaft system for pinned-pinned (P-P), clamped-free (C-F) and clamped-free (C-F) boundaries condition. The Nelson’s finite element model that considers the torsional effect was developed for formulating the finite element (FE) model. This FE model was used to derive Mathieu-Hill’s equation and then solved by applying the Bolotin’s theory. From the solution, the Campbell’s diagram of the high-speed shaft was plotted. It was found that torsional motion has significant effect on the critical speed for different boundary conditions. The difference between critical speed of 4DOF and 5DOF models can be as high as 6.91 %.

scholarly journals Finite Element Simulation for Dynamic Performance of a Dummy’s Head in Helicopter Anti-prang Tests

2018 ◽  
Vol 232 ◽  
pp. 02006
Author(s):  
Jingfa Lei ◽  
Yan Xuan ◽  
Tao Liu ◽  
Miao Zhang ◽  
Hong Sun
Keyword(s):  
Finite Element ◽  
Dynamic Performance ◽  
Reference Value ◽  
Element Model ◽  
Simulation Method ◽  
Head Model ◽  
Fe Model ◽  
Element Simulation ◽  
Dynamic Performances ◽  
Reference Index

The dynamic performance of a dummy’s head plays a important role in the research of helicopter anti-prang testing. In this paper, we firstly construct the finite element model for a dummy’s head based on the parameter features of 50th percentile Chinese pilot. Then, the dynamic performance of the head model is simulated according to the calibration rules. After comparing the simulation results with the reference index of the dummy head’s dynamic performances, we find that the FE model has good anthropopathic integrality, and the simulation method used to analyze the dynamic performance of the dummy’s head is correct and validated. This paper has practical guiding significance in the study of helicopter anti-prang testing and other dummy parts, which also provide the reference value for the improvement of dummy structure.

The Local Stress Analysis for the Anchorage Zone of Tooth Plate in Steel Box Girder

2013 ◽  
Vol 477-478 ◽  
pp. 631-634
Author(s):  
Zuo Long Luo ◽  
Jiang Long Wang ◽  
Feng Hui Dong
Keyword(s):  
Finite Element ◽  
Comparative Analysis ◽  
Local Stress ◽  
Element Model ◽  
Maximum Difference ◽  
Box Girder ◽  
Steel Box Girder ◽  
Tooth Plate ◽  
The Difference ◽  
Different Parts

Calculating the local stress for the anchorage zone of each part in the tooth plate by establishing two kinds of finite element model: considering concrete effect and not considering concrete effect. The result of the comparative analysis of the two models shows that the local stress considering the concrete effect is smaller than that not considering the concrete effect and the maximum difference is about 170 MPa. The difference is not the same in different parts of the tooth plate. Although the design will be tend to be safe for not considering the concrete effect, the size of the tooth plate may increase. Therefore, in order to reduce the weight of the tooth plate , the concrete effect should be taken into consideration in the design.

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