Research on Hexahedral and Tetrahedral Mesh Applied to Strength Analysis of Bogie Frame

2013 ◽  
Vol 477-478 ◽  
pp. 150-154 ◽  
Author(s):  
Guang Jun Li ◽  
Wen Jing Wang ◽  
Li An ◽  
Ze Jin Zhang
Keyword(s):  
Structural Model ◽  
Complex Structure ◽  
Tetrahedral Mesh ◽  
Bench Test ◽  
Strength Analysis ◽  
Structure Model ◽  
Stress Distributions ◽  
Bogie Frame ◽  
Tetrahedral Elements ◽  
Experimental Values

The structure of bogie frame is meshed by hexahedral and tetrahedral elements respectively. FE analysis is taken based on the loads defined by JIS E 4207 standard and the stress distributions of two separate models are obtained. To clarify the accuracy of two kinds of finite element models, the bench test of the bogie frame is carried out. It shows that both the hexahedral and tetrahedral models are valid according to the comparison between FE results and experimental values when the structural model is regular. However, for complex structure model 10-node tetrahedral model takes precedence.

scholarly journals KAJIAN EFISIENSI PERENCANAAN PC-I GIRDER DENGAN MENGGUNAKAN SISTEM STRAND 0,5” DAN 0,6” TERHADAP KEKUATAN DAN BIAYA

2020 ◽  
Vol 3 (1) ◽  
pp. 11
Author(s):  
Jessen Richarlim ◽  
Edison Leo
Keyword(s):  
Prestressed Concrete ◽  
Structural Model ◽  
System Structure ◽  
Strength Analysis ◽  
Structure Model ◽  
Dead Load ◽  
Long Span ◽  
Long Span Bridge ◽  
Deflection Analysis ◽  
The Cost

Prestressed concrete can be defined as concrete that given internal compressive stress such that it can reduce the tensile stress caused by external load to a certain condition. Stressing applied by pulling the tendon that has been installed on the concrete. 0,5” strand system are usually used for medium span. While 0,6” strand system is used for long span bridge. The purpose of this study was to determine the efficiency of PC-I girder using 0,5 "and 0,6" strands in terms of strength and cost. Strength analysis can be calculated by stress analysis, ultimate moment analysis and deflection analysis, while for cost analysis is a comparison of the cost composition between the 0,5 "and 0,6" strand system for each structural model reviewed. Structural modeling with hinge-roll at both ends and working loadings are dead load, additional dead load and live load. Loss of prestress force that is calculated depend on SNI 1725:2016 about loading for the bridge. The analysis shows that the use of the 0,5” strand has a better cost efficiency compared to the 0,6" strand. This can be seen from the design costs of the 0,5" strand system structure model is smaller than the 0,6" strand system structure model. AbstrakBeton prategang dapat didefinisikan sebagai beton yang diberikan tegangan tekan internal sedemikian rupa sehingga dapat mengurangi tegangan tarik yang terjadi akibat beban eksternal sampai suatu batas tertentu. Pemberian tegangan dilakukan dengan cara penarikan tendon yang telah diinstalasi pada beton. Sistem strand ukuran 0,5” biasanya digunakan untuk konstruksi jembatan bentang menengah. Sedangkan sistem strand ukuran 0,6” digunakan untuk konstruksi jembatan bentang panjang. Tujuan dari penelitian ini adalah untuk mengetahui efisiensi perencanaan PC-I girder dengan menggunakan strand 0,5” dan 0,6” dalam segi kekuatan dan biayanya. Analisis segi kekuatan berupa analisis tegangan, analisis momen ultimit dan analisis lendutan sedangkan untuk analisis segi biaya berupa perbandingan komposisi biaya yang dihasilkan dengan sistem strand 0,5” dan 0,6” untuk setiap model struktur yang ditinjau. Pemodelan struktur dengan perletakan sendi-rol pada kedua ujungnya dan pembebanan yang bekerja berupa beban mati, beban mati tambahan dan beban hidup. Kehilangan gaya prategang yang diperhitungkan sesuai dengan peraturan SNI 1725:2016 tentang Pembebanan Untuk Jembatan. Hasil analisis menunjukkan bahwa penggunaan strand 0,5” memiliki efisiensi biaya yang lebih baik dibandingkan dengan strand 0,6”. Hal ini dilihat dari biaya desain model struktur sistem strand 0,5” lebih kecil dibandingkan dengan model struktur sistem strand 0,6”.

Dynamic simulation of the motion of capsules in pipelines

1995 ◽  
Vol 286 ◽  
pp. 201-227 ◽  
Author(s):  
J. Feng ◽  
P. Y. Huang ◽  
D. D. Joseph
Keyword(s):  
Lift Force ◽  
Two Dimensions ◽  
Inertial Forces ◽  
Stress Distributions ◽  
Three Stages ◽  
Heavy Crude ◽  
Lift Off ◽  
Experimental Values ◽  
Transient Oscillations ◽  
Core Flows

In this paper we report results of two-dimensional simulations of the motion of elliptic capsules carried by a Poiseuille flow in a channel. The numerical method allows computation of the capsule motion and the fluid flow around the capsule, and accurate evaluation of the lift force and torque. Results show that the motion of a capsule which is heavier than the carrying fluid may be decomposed into three stages: initial lift-off, transient oscillations and steady flying. The behaviour of the capsule during initial lift-off and steady flying is analysed by studying the pressure and shear stress distributions on the capsule. The dominant mechanism for the lift force and torque is lubrication or inertia or a combination of the two under different conditions. The lift-off velocity for the ellipse in two dimensions is compared with experimental values for cylindrical capsules in pipes. Finally, the mechanisms of lift for capsules are applied to flying core flows, and it is argued that inertial forces are responsible for levitating heavy crude oil cores lubricated by water in a horizontal pipeline.

FRACTAL PORE STRUCTURE MODEL AND MULTILAYER FRACTAL ADSORPTION IN SHALE

Fractals ◽  
2014 ◽  
Vol 22 (03) ◽  
pp. 1440010 ◽  
Author(s):  
LIEHUI ZHANG ◽  
JIANCHAO LI ◽  
HONGMING TANG ◽  
JINGJING GUO
Keyword(s):  
Fractal Dimension ◽  
Pore Structure ◽  
Saturated Vapor ◽  
Adsorption Property ◽  
Fractal Theory ◽  
Complex Structure ◽  
Structure Model ◽  
Adsorption Model ◽  
Adsorption Volume ◽  
Isothermal Adsorption

The complex structure and surface property of porous media have significant impact on its accumulation and adsorption capacity. Based on the fractal theory, this paper presents a fractal pore structure model for shales. The effect of different pore structures on fractal dimension is discussed, and the influence of fractal dimension and pore size distribution on porosity is also analyzed. It is shown that the fractal dimension D decreases with the increase of structure parameter q/m for a certain pore diameter ratio, and porosity has positive relationship with fractal dimension. This paper also presents a multilayer fractal adsorption model which takes into account the roughness of adsorption surface by using fractal theory. With the introduction of pseudo-saturated vapor pressure in the supercritical temperature condition, the proposed adsorption model can be applied into a wider range of temperature. Based on the low-pressure nitrogen adsorption and methane isothermal adsorption experiments, the effect of fractal dimension on the adsorption behavior of shales is discussed. Fractal dimension has significant impact on the surface adsorption property and adsorption layer number n. The monolayer saturated adsorption volume Vm increases with the increase of D, while parameter C has the opposite variation trend. Finally, the optimal combination of fractal parameters for describing pore structure of shale samples is selected.

scholarly journals An efficient three-dimensional foil structure model for bump-type gas foil bearings considering friction

Friction ◽  
2020 ◽  
Author(s):  
Yongpeng Gu ◽  
Xudong Lan ◽  
Gexue Ren ◽  
Ming Zhou
Keyword(s):  
Structural Model ◽  
Three Dimensional ◽  
Element Model ◽  
Experimental Results ◽  
Synthesis Methods ◽  
Structure Model ◽  
Foil Bearings ◽  
Static Responses ◽  
Bearing Sleeve ◽  
Shell Finite Element

Abstract This paper presents an efficient three-dimensional (3D) structural model for bump-type gas foil bearings (GFBs) developed by considering friction. The foil structures are modeled with a 3D shell finite element model. Using the bump foil mechanical characteristics, the Guyan reduction and component mode synthesis methods are adopted to improve computational efficiency while guaranteeing accurate static responses. A contact model that includes friction and separation behaviors is presented to model the interactions of the bump foil with the top foil and bearing sleeve. The proposed structural model was validated with published analytical and experimental results. The coupled elastohydrodynamics model of GFBs was established by integration of the proposed structural model with data on hydrodynamic films, and it was validated by comparisons with existing experimental results. The performance of a bearing with an angular misalignment was studied numerically, revealing that the reaction torques of the misaligned bearing predicted by GFB models with 2D and 3D foil structure models are quite different. The 3D foil structure model should be used to study GFB misalignment.

scholarly journals Structural model and dynamic analysis of six-axis Cartesian coordinate robot for sheet metal bending

2019 ◽  
Vol 16 (4) ◽  
pp. 172988141986156
Author(s):  
Fengyu Xu ◽  
Quansheng Jiang ◽  
Lina Rong ◽  
Pengfei Zhou ◽  
Jinlong Hu
Keyword(s):  
Dynamic Analysis ◽  
Sheet Metal ◽  
Laboratory Testing ◽  
Structural Model ◽  
Dynamic Performance ◽  
Work Conditions ◽  
Structure Model ◽  
Sheet Metal Bending ◽  
Cartesian Coordinate ◽  
The Stability

Bending is an important procedure for processing sheet metals, while it is a key link in the realization of automatic processing of sheet metal. To improve the efficiency and accuracy of bending processing, this article proposed a structure model and a prototype of a six-axis Cartesian coordinate robot for sheet metal bending to replace workers completing automatic bending processes. Based on the analysis of overall structure schemes of the robot, kinematic simulation is conducted by using the automatic dynamic analysis of mechanical system (ADAMS). Furthermore, the dynamic performance of the structural model of the robot for sheet metal bending is analysed and design optimization is performed. A prototype of the robot based on the optimal structural model of six-axis Cartesian coordinate robot for sheet metal bending is made. Finally, under the work conditions, the efficiencies and accuracies of sheet metal bending by a worker and the robot are compared and tested. The structural model of six-axis Cartesian coordinate robot for sheet metal bending presented in this article is found to be applicable to sheet metal bending robot and improves the stability of sheet metal bending machine. The laboratory testing and experimental results verified the feasibility of the proposed robot.

Configurable Product Structure Model Based on Semantic Network

2013 ◽  
Vol 655-657 ◽  
pp. 2074-2079
Author(s):  
Xin Wang ◽  
Lin Gao ◽  
Chong Chong Ji
Keyword(s):  
Knowledge Representation ◽  
Structural Model ◽  
Semantic Network ◽  
Semantic Networks ◽  
Product Structure ◽  
Semantic Relation ◽  
Product Configuration ◽  
Configuration Design ◽  
Structure Model ◽  
Representation Form

Depending on the demand of structure model in product configuration design, product types that can be configured are described and analyzed. Based on semantic networks as a kind of available knowledge representation form and Extend A/O tree, structural model of configurable product is put forward. The structural relation, assembly relation and configuring option relation are included, semantic relation among assembly parts is also expressed. Finaly, configurable node model is proposed.

scholarly journals Fatigue strength analysis of bogie frames under random loads

2019 ◽  
Vol 11 (9) ◽  
pp. 168781401987801 ◽  
Author(s):  
Qi An ◽  
Hua Zhao ◽  
Peihai Li ◽  
Maohai Fu
Keyword(s):  
Fatigue Strength ◽  
Coordinate System ◽  
Welded Joints ◽  
Strength Analysis ◽  
Node Degree ◽  
International Institute ◽  
Bogie Frame ◽  
Welding Method ◽  
Stress Components ◽  
Time Histories

In this study, a method for analyzing the fatigue strength of a bogie frame under a random load was proposed. Based on the geometric features, a welded joint coordinate system was established to compute the stress components of each node in this coordinate system. With the influence of small amplitude cycles included, based on the corrected S–N curve and a method for calculating the equivalent constant amplitude stress, the node and comprehensive degree of utilization were calculated based on the anti-fatigue design grade of welded joints to evaluate the fatigue strength of a structure under a given lifespan. The FKM and International Institute of Welding methods were used to evaluate the fatigue strength of typical welded joints of a bogie frame. The characteristics of the node degree of utilization under different analytical methods were compared, and the results showed that when the time histories of the three stress components of the nodes had significant non-proportional features, the FKM method obtained conservative results. When the time histories of the three stress components of the nodes were synchronized, the criterion value specified by the International Institute of Welding method was the main factor affecting the distribution characteristics of the node degree of utilization. The analysis based on the International Institute of Welding method can effectively balance the lightweight design and reliability of the structure.

FEA Analysis of Subsea Mooring Suction Anchor Under Operation Condition

2015 ◽  
Author(s):  
Shuqin Wang ◽  
Jiaping Zhang ◽  
Jim Malachowski ◽  
Jubair Hossain ◽  
James Colling
Keyword(s):  
Structural Engineering ◽  
Structural Model ◽  
Limit State ◽  
Strength Analysis ◽  
Soil Parameters ◽  
Soil Reaction ◽  
Soil Pressure ◽  
Operation Condition ◽  
Limit States ◽  
Conservative Result

The analysis of a mooring suction anchor involves both geotechnical and structural engineering. The design starts with the geotechnical analysis of a mooring suction anchor where the design loads are used to determine the size of the mooring suction anchor. Typically, a conservative estimate would be made for the soil strength and analysis would involve several layers of soil with different properties. The mooring suction anchor is then designed using the relevant soil parameters for various limit states under the combined vertical, lateral, torsional, and moment loading. Soil pressures or reactions acting on a rigid steel mooring suction anchor for each limit state are calculated. The calculation results are then provided to structural engineers to perform strength analysis to verify the integrity of the anchor. Therefore, it is important to understand how the soil reactions interact with the suction anchor in the structural model. The current analysis used the soil reaction data developed for an in-place loading condition for a mooring suction anchor. The structure of the mooring suction anchor was modelled using a 3D finite element method. Two studies were performed. The first study performed the regular mapping of the soil pressure to the suction anchor. The second study assumed that all the loads would be applied on the mooring padeye and the bottom of the suction would be fixed. It was presumed that the second study would yield a conservative result. However, the analysis results showed that the second study did not provide a conservative result. Therefore, it is recommended that the care should be taken when making such assumptions in future studies.

A Comparison of the Performance of Hexahedral and Tetrahedral Elements in Finite Element Models of the Foot

2010 ◽  
Author(s):  
Srinivas C. Tadepalli ◽  
Ahmet Erdemir ◽  
Peter R. Cavanagh
Keyword(s):  
Finite Element ◽  
Mesh Generation ◽  
Complex Structure ◽  
Shear Loading ◽  
Superior Performance ◽  
Hexahedral Mesh ◽  
Tetrahedral Elements ◽  
Heel Pad ◽  
Hexahedral Elements ◽  
Foot Biomechanics

Characterization of the contact pressure patterns under the foot provides significant insight into pathological conditions such as diabetic peripheral neuropathy [1]. The finite element method (FEM) is widely used in foot biomechanics for predictive simulations of plantar pressures in barefoot and shod conditions [2–6]. In the analysis of the foot, mesh generation accounts for most of the labor in model development, due to the complex structure of the foot including highly partitioned, embedded, and branching geometries. In FEM, hexahedral elements are preferred over tetrahedral elements because of their superior performance in terms of convergence and accuracy of the solution [7]. This becomes more apparent as the convergence behavior of the simulations are hindered by large deformation, material incompressibility, and contact with friction, mechanical features which are commonly seen in foot biomechanics. Unfortunately, unlike tetrahedral meshing which is highly automated [8], hexahedral mesh generation is a time consuming process requiring considerable operator intervention. Despite their reputed advantages, the relative performance of tetrahedral meshes in foot models has not been well established; to our knowledge, there has not been a comprehensive study comparing the performance of hexahedral and tetrahedral elements when material and geometric nonlinearity are included combined with material incompressibility and shear force loading conditions. Hence, the objective of the present study was to evaluate various types of meshes that can be used to model the interaction of a bone-soft tissue construct and rigid floor complex under compressive and shear loading in a heel-pad analog model.

Sign in / Sign up

Export Citation Format

Share Document