Welding Distortion Minimization for an Aluminum Alloy Extruded Beam Structure Using a 2D Model

2004 ◽  
Vol 126 (1) ◽  
pp. 52-63 ◽  
Author(s):  
Bart O. Nnaji ◽  
Deepak Gupta ◽  
Kyoung-Yun Kim
Keyword(s):  
Aluminum Alloy ◽  
Quality Index ◽  
Bending Moment ◽  
Element Model ◽  
Maximum Principal Stress ◽  
Welding Distortion ◽  
Beam Structure ◽  
Critical Areas ◽  
Distortion Minimization ◽  
Nonlinear Transient

Optimization of the weld sequence of a sub-assembly composed of thin walled aluminum alloy extruded beams is investigated and presented. The main factor considered is the quality of the assembly after welding, which is measured by the deformation behavior at pre-defined critical locations. The aluminum alloy extruded beam structure is simplified by a 2-D beam element model. Our methodology consists of applying pre-estimated angular shrinkages for each welding step thus eliminating use of a complex nonlinear transient analysis which would require consideration of thermo-mechanical interactions and plasticity. Two distortion modes (angular shrinkage and tilting shrinkage) are investigated and applied to model welding distortion. Different criteria for minimization of welding distortion have been investigated, such as overall deformation or weighted deformation with emphasis on some critical areas. A composite quality index is formulated, which is a weighted measure of critical deformation and the overall deformation. For simulating welding deformation and the role of sequences, some weld sequences were selected heuristically and they were simulated in ANSYS 5.2. Based on the quality index of these sequences, some were reproduced while mutating other portions of these sequences to find better sequences. Finally, deformation data for each node and weighted measures of deformation for considered sequences are presented, and final deformed shapes for different sequences, maximum principal stress, and bending moment across the beams are shown graphically.

NONLINEAR TRANSIENT ANALYSIS OF A RAILWAY CONCRETE SLEEPER IN A TRACK SYSTEM

2008 ◽  
Vol 08 (03) ◽  
pp. 505-520 ◽  
Author(s):  
SAKDIRAT KAEWUNRUEN ◽  
ALEX M. REMENNIKOV
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Bending Moment ◽  
Element Model ◽  
Beam Elements ◽  
Finite Element Software ◽  
Track System ◽  
Wide Range ◽  
Nonlinear Transient ◽  
Dynamic Magnification Factor

Railway sleepers in a track system are usually subjected to a wide range of loading conditions. A critical type of loading condition that causes cracking in the railway concrete sleepers is the dynamic transient wheel force. The transient wheel forces are often due to wheel or rail abnormalities. This paper presents a dynamic finite element model of a railway concrete sleeper in a track system, aimed at raising the consideration of dynamic effects in sleeper design. The railway concrete sleeper is modeled using the beam-on-elastic-foundation theory. Since in the actual tracks the ballast underneath does not provide any tensile resistance, the finite beam elements employed in this investigation take into account the bending and shear deformations, together with the tensionless nature of the elastic support. This paper places emphasis on the effect of the transient periods on the flexural responses of railway sleepers in track systems. Using the robust finite element software STRAND7, the finite element model of the railway concrete sleeper was previously established and validated against experimental data by the authors. The numerical analyses present the ratio between the dynamic and the static bending moment resultants, the dynamic magnification factor, of the railway concrete sleeper under different sinusoidal pulse durations.

scholarly journals Residual Stress Analysis of a 2219 Aluminum Alloy Ring Using the Indentation Strain-Gauge Method

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 979
Author(s):  
Yunlong Ma ◽  
Nianpu Xue ◽  
Qiong Wu ◽  
Hanjun Gao ◽  
Jian Wu
Keyword(s):  
Residual Stress ◽  
Aluminum Alloy ◽  
Strain Gauge ◽  
Expansion Method ◽  
Element Model ◽  
Maximum Principal Stress ◽  
Initial Residual Stress ◽  
2219 Aluminum Alloy ◽  
Rolling Ring ◽  
Indentation Strain

Aerospace thin-walled rings are vulnerable to machining distortion during the manufacturing process. Various research results show that the main factor causing machining deformation is initial residual stress inside the blank. In this study, the residual stress of a 2219 aluminum alloy ultra-large rolling ring was measured by using the indentation strain-gauge method. Results showed the maximum residual maximum principal stress was +265 MPa and stress distribution was uneven. To homogenize the initial residual stress of the ring, an expansion method is proposed based on the principle of pre-stretching plate, and the feasibility of the expansion method was analyzed by establishing a simplified theoretical model of ring. A FE (Finite Element) model was established to investigate residual-stress evolution during the rolling ring and the expanding ring process. The expansion simulation results show that the reduction rates of residual stress were greater than 40% and the maximum residual stress was only 65 MPa.

Global Structural Response Analysis of Jack-Up Ship in Transit Condition

2013 ◽  
Vol 344 ◽  
pp. 66-69
Author(s):  
Xiang Zhu ◽  
Yong Sheng Tang ◽  
Yao Zhao ◽  
Heng Kui Ye
Keyword(s):  
Structural Response ◽  
Bending Moment ◽  
Element Model ◽  
Inertia Force ◽  
Response Analysis ◽  
Wave Loads ◽  
Critical Areas ◽  
Hull Structure ◽  
In Transit ◽  
Jack Up

The global structural response of a four-leg jack-up wind turbine installation ship in the transit condition was analyzed in this paper. The finite element model of the hull and legs were established with the Software MSC. PATRAN. On the basis of long-term forecast of the wave loads, the corresponding designed wave parameters are determined with the vertical wave bending moment of the midship cross section served as the main load control parameter. Considering the gravity, hydrostatic pressure, the hydrodynamic loads induced by the wave, inertia force induced by the motion and acceleration of the ship and the wind force on the legs and hull, the direct calculated method was used to evaluate the global structural response of the vessel. The deformation and stress of the hull and legs were calculated and checked. The results showed that the strength of the hull and leg could meet the rules requirements. For the jack-up ship in the transit condition, the critical areas are mainly lower part of legs and the corresponding hull structure.

scholarly journals Internal Force on and Deformation of Steel Assembled Supporting Structure of Foundation Pit under Thermal Stress

2021 ◽  
Vol 11 (5) ◽  
pp. 2225
Author(s):  
Fu Wang ◽  
Guijun Shi ◽  
Wenbo Zhai ◽  
Bin Li ◽  
Chao Zhang ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Bending Moment ◽  
High Strength ◽  
Element Model ◽  
Internal Force ◽  
Foundation Pit ◽  
Dimensional Finite Element ◽  
Influence Of Temperature On ◽  
Scale Experiment ◽  
Three Dimensional Finite Element

The steel assembled support structure of a foundation pit can be assembled easily with high strength and recycling value. Steel’s performance is significantly affected by the surrounding temperature due to its temperature sensitivity. Here, a full-scale experiment was conducted to study the influence of temperature on the internal force and deformation of supporting structures, and a three-dimensional finite element model was established for comparative analysis. The test results showed that under the temperature effect, the deformation of the central retaining pile was composed of rigid rotation and flexural deformation, while the adjacent pile of central retaining pile only experienced flexural deformation. The stress on the retaining pile crown changed little, while more stress accumulated at the bottom. Compared with the crown beam and waist beam 2, the stress on waist beam 1 was significantly affected by the temperature and increased by about 0.70 MPa/°C. Meanwhile, the stress of the rigid panel was greatly affected by the temperature, increasing 78% and 82% when the temperature increased by 15 °C on rigid panel 1 and rigid panel 2, respectively. The comparative simulation results indicated that the bending moment and shear strength of pile 1 were markedly affected by the temperature, but pile 2 and pile 3 were basically stable. Lastly, as the temperature varied, waist beam 2 had the largest change in the deflection, followed by waist beam 1; the crown beam experienced the smallest change in the deflection.

Character Analysis of Balance and Imbalance of Varying Rigidity of Rigid Pile Composite Foundation under Seismic Load

2014 ◽  
Vol 1065-1069 ◽  
pp. 19-22
Author(s):  
Zhen Feng Wang ◽  
Ke Sheng Ma
Keyword(s):  
Finite Element ◽  
Bending Moment ◽  
Horizontal Displacement ◽  
Element Model ◽  
Composite Foundation ◽  
Seismic Load ◽  
Seismic Loads ◽  
Element Analysis ◽  
Rigid Pile ◽  
Rigid Pile Composite Foundation

Based on ABAQUS finite element analysis software simulation, the finite element model for dynamic analysis of rigid pile composite foundation and superstructure interaction system is established, which selects the two kinds of models, by simulating the soil dynamic constitutive model, selecting appropriate artificial boundary.The influence of rigid pile composite foundation on balance and imbalance of varying rigidity is analyzed under seismic loads. The result shows that the maximum bending moment and the horizontal displacement of the long pile is much greater than that of the short pile under seismic loads, the long pile of bending moment is larger in the position of stiffness change. By constrast, under the same economic condition, the aseismic performance of of rigid pile composite foundation on balance of varying rigidity is better than that of rigid pile composite foundation on imbalance of varying rigidity.

Research on Friction between Grade Flat Approach Slab and Sliding Material in Jointless Bridges

2019 ◽  
Author(s):  
Yufeng Tang ◽  
Bruno Briseghella ◽  
Junqing Xue ◽  
Peiquan Zhang ◽  
Fuyun Huang ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Life Cycle Cost ◽  
Bending Moment ◽  
Horizontal Displacement ◽  
Element Model ◽  
Expansion Joints ◽  
Approach Slab ◽  
Jointless Bridges ◽  
Friction Function ◽  
The Mathematical Model

<p>The application of jointless bridges has been increasing year by year, because it could reduce the life‐cycle cost and improve the riding comfort. The approach slab in jointless bridges does not only have the function of road transition which is the same as the approach slab in bridges with expansion joints, but also transfer and absorb the deformation produced by the thermal expansion and contraction of the girder. The Grade Flat Approach Slab (GFAS) horizontally placed on the subgrade is one of the most common types of the approach slab in jointless bridges. The material placed between GFAS and subgrade should be able to properly slide to reduce the stress in GFAS. The friction coefficient between GFAS and sliding material is an important parameter affecting the mechanical behavior of GFAS in jointless bridges. In this paper, the tests of GFAS with different sliding materials subjected to horizontal displacement were conducted to obtain the corresponding friction coefficients (from 0.34 to 0.68). The mathematical model of bilinear spring could be adapted to simulate the friction function between GFAS and different sliding materials. One Deck‐Extension Bridge (DEB) that is one type of jointless bridges was chosen as a case study. The finite element model was implemented by using Midas‐Civil software. The influence of GFAS with different sliding materials on the mechanical properties of DEB under temperature variation was investigated. It can be concluded that the influence of the friction coefficient between GFAS and sliding material on the bending moment of DEB should be taken into account.</p>

scholarly journals Dynamic Response Evaluation of Long-Span Reinforced Arch Bridges Subjected to Near- and Far-Field Ground Motions

2018 ◽  
Vol 8 (8) ◽  
pp. 1243 ◽  
Author(s):  
Iman Mohseni ◽  
Hamidreza Lashkariani ◽  
Junsuk Kang ◽  
Thomas Kang
Keyword(s):  
Ground Motion ◽  
Dynamic Performance ◽  
Time History ◽  
Bending Moment ◽  
Element Model ◽  
Structural Performance ◽  
Far Field ◽  
Inelastic Behavior ◽  
Earthquake Loads ◽  
Arch Bridges

This study assessed the structural performance of reinforced concrete (RC) arch bridges under strong ground motion. A detailed three-dimensional finite element model of a 400 m RC arch bridge with composite superstructure and double RC piers was developed and its behavior when subjected to strong earthquakes examined. Two sets of ground motion records were applied to simulate pulse-type near- and far-field motions. The inelastic behavior of the concrete elements was then evaluated via a seismic time history analysis. The concept of Demand to Capacity Ratios (DCR) was utilized to produce an initial estimate of the dynamic performance of the structure, emphasizing the importance of capacity distribution of force and bending moment within the RC arch and the springings and piers of the bridge. The results showed that the earthquake loads, broadly categorized as near- and far-field earthquake loads, changed a number of the bridge’s characteristics and hence its structural performance.

scholarly journals WAVE ANALYSIS OF A L-BEAM STRUCTURE WITH A BLOCKING MASS

2020 ◽  
Author(s):  
Johnny Tiu ◽  
Richard Bachoo
Keyword(s):  
Systematic Approach ◽  
Building Blocks ◽  
Element Model ◽  
Structural Systems ◽  
Structural Elements ◽  
Wave Analysis ◽  
Beam Structure ◽  
Reflection Matrix ◽  
Geometric Changes ◽  
Transmission And Reflection

The wave vibration approach regards the vibrations present within a structure as waves, whereby each wave flows along a structural member and upon meeting a discontinuity; portions of the incident wave are reflected and transmitted across the discontinuity. The reflected, transmitted and propagating wave transformations are represented mathematically by matrices, which are used to develop a set of wave relation equations at each discontinuity that can be used to describe the frequency response of the system holistically. This method creates a systematic approach of analysing structures by utilizing common cases as building blocks for a specific structure. The L-joint, described as two beams meeting at right angles; is a ubiquitous case for spatial portal and structural frames, which may become geometrically complex. Such structures are well suited to a wave vibration approach due to the large number of geometric changes and the prevalence as well as recurrence of specific cases. In this paper, the L-joint expanded to include a blocking mass, typically employed in structural systems and allows for the isolation and reflection of vibration away from contiguous structural elements. Included are; variance of transmission and reflection matrix components as the size of the blocking mass increases, numerical examples and comparison to a Finite Element Model developed in ANSYS.

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