scholarly journals Trustworthiness in Modeling Unreinforced and Reinforced T-Joints with Finite Elements

2019 ◽  
Vol 24 (1) ◽  
pp. 27 ◽  
Author(s):  
Slimane Ouakka ◽  
Nicholas Fantuzzi
Keyword(s):  
Finite Element ◽  
Static Strength ◽  
Fe Model ◽  
Static Behavior ◽  
T Joints ◽  
Shell Elements ◽  
Mesh Density ◽  
Element Type ◽  
Material Discontinuities ◽  
Conclusion Section

As required by regulations, Finite Element Analyses (FEA) can be used to investigate the behavior of joints which might be complex to design due to the presence of geometrical and material discontinuities. The static behavior of such problems is mesh dependent, thus these results must be calibrated by using laboratory tests or reference data. Once the Finite Element (FE) model is correctly setup, the same settings can be used to study joints for which no reference is available. The present work analyzes the static strength of reinforced T-joints and sheds light on the following aspects: shell elements are a valid alternative to solid modeling; the best combination of element type and mesh density for several configurations is shown; the ultimate static strength of joints can be predicted, as well as when mechanical properties are roughly introduced for some FE topologies. The increase in strength of 12 unreinforced and reinforced (with collar or doubler plate) T-joints subjected to axial brace loading is studied. The present studies are compared with the literature and practical remarks are given in the conclusion section.

scholarly journals Design and Structural Analysis of a Rack System for Using in Agriculture

2018 ◽  
Vol 66 (3) ◽  
pp. 641-646
Author(s):  
Miroslav Blatnický ◽  
Ján Dižo ◽  
Dalibor Barta
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Structural Analysis ◽  
Fe Model ◽  
Steel Tubes ◽  
Shell Elements ◽  
Human Power ◽  
Construction Design ◽  
Pull Out ◽  
Pressure Pipeline

The paper deals with a construction design and structural analysis of the rack system which will be used for storage of steel tubes of pressure pipeline for fodder mixtures transportation in agricultural company. Structure of the designed equipment is made by the welding of steel parts and consists of the main framework and four pull-out racks on both sides. Racks move by means of human power through a rotating crank. Every individual pull-out racks is able to carries pipes of various dimensions, both length and diameter with total weight up to 3 tons with respect to customer requests. Since it is a prototype’s structure, we have designed main dimensions of it, material and technology for production and performed also structural analyses as the integral part of every engineering design. Structural analyses were conducted by means of numeric procedure known as finite element method. With respect to the used steel profiles shell elements were used for FE model. Analyses were performed for maximal loading cases in order to identify the level of safety in the most exposed locations of the structure.

Finite Element Analysis of Elliptical Chord

2013 ◽  
Vol 3 (4) ◽  
pp. 44-61
Author(s):  
K. S. Narayana ◽  
R. T. Naik ◽  
R. C. Mouli ◽  
L. V. V. Gopala Rao ◽  
R. T. Babu Naik
Keyword(s):  
Finite Element ◽  
Natural Frequencies ◽  
Three Dimensional ◽  
Compressive Load ◽  
Dynamic Strength ◽  
Element Analysis ◽  
T Joints ◽  
Shell Elements ◽  
Tubular Joints ◽  
Plane Bending

The work presents the Finite element study of the effect of elliptical chords on the static and dynamic strength of tubular T-joints using ANSYS. Two different geometry configurations of the T-joints have been used, namely Type-1 and Type-2. An elastic analysis has been considered. The Static loading conditions used are: axial load, compressive load, In-plane bending (IPB) and Out-plane bending (OPB). The natural frequencies analysis (dynamic loading condition) has also been carried out. The geometry configurations of the T-joints have been used, vertical tubes are called brace and horizontal tubes are called chords. The joint consists of brace joined perpendicular to the circular chord. In this case the ends of the chord are held fixed. The material used is mild steel. Using ANSYS, finite element modeling and analysis of T-joint has been done under the aforementioned loading cases. It is one of the most powerful methods in use but in many cases it is an expensive analysis especially due to elastic–plastic and creep problems. Usually, three dimensional solid elements or shell elements or the combination of two types of elements are used for generating the tubular joints mesh. In tubular joints, usually the fluid induced vibrations cause the joint to fail under resonance. Therefore the natural frequencies analysis is also an important issue here. Generally the empirical results are required as guide or comparison tool for finite element investigation. It is an effective way to obtain confidence in the results derived. Shell elements have been used to model the assembled geometry. Finite element ANSYS results have been validated with the LUSAS FEA and experimental results, that is within the experimentation error limit of ten percentage.

Continuum Finite Element Methods to Establish Compressive Strain Limits for Offshore Pipelines in Ice Gouge Environments

2007 ◽  
Author(s):  
Ali Fatemi ◽  
Shawn Kenny ◽  
Farid Taheri
Keyword(s):  
Finite Element ◽  
Finite Element Methods ◽  
Compressive Strain ◽  
Pipeline System ◽  
Operational Parameters ◽  
Offshore Pipelines ◽  
Geometric Imperfection ◽  
Mesh Density ◽  
Post Buckling ◽  
Element Type

In the design process for offshore pipelines in ice gouge environments, compressive strain limits provide a basis to assess pipeline mechanical integrity for design load events. A parametric study, using the continuum finite element methods, has been conducted to assess the global pipeline moment-curvature response for displacement-based loading conditions through the post-buckling regime. The purpose of this study was to investigate the accuracy and efficiency of some computational parameters in simulating the stability characteristics of thick pipes. For that, the study used a pipe that has been the subject of a comprehensive and extensive experimental investigation. In specific, the study selected the exact geometric, material, loadings, boundary conditions and operational parameters similar to the BPXA Northstar pipeline system. The numerical analysis examined the effect of element type, mesh density, internal pressure, axial load, end moment, and geometric imperfection mode on the predicted post-buckling response. The analysis demonstrated the importance of element type, mesh density and characteristics of initial geometric imperfections on the post-buckling response of a thick-walled pipeline subject to combine loads. In addition, element performance and solution efficiency was examined.

scholarly journals An Efficient and General Finite Element Model for Double-Sided Incremental Forming

2016 ◽  
Vol 138 (9) ◽  
Author(s):  
Newell Moser ◽  
David Pritchet ◽  
Huaqing Ren ◽  
Kornel F. Ehmann ◽  
Jian Cao
Keyword(s):  
Finite Element ◽  
Incremental Forming ◽  
Mesh Size ◽  
Element Model ◽  
Explicit Finite Element ◽  
Fully Integrated ◽  
Shell Elements ◽  
Mass Scaling ◽  
Element Simulation ◽  
Element Type

Double-sided incremental forming (DSIF) is a subcategory of general incremental sheet forming (ISF), and uses tools above and below a sheet of metal to squeeze and bend the material into freeform geometries. Due to the relatively slow nature of the DSIF process and the necessity to capture through-thickness mechanics, typical finite element simulations require weeks or even months to finish. In this study, an explicit finite element simulation framework was developed in LS-DYNA using fully integrated shell elements in an effort to lower the typical simulation time while still capturing the mechanics of DSIF. The tool speed, mesh size, element type, and amount of mass scaling were each varied in order to achieve a fast simulation with minimal sacrifice regarding accuracy. Using 8 CPUs, the finalized DSIF model simulated a funnel toolpath in just one day. Experimental strains, forces, and overall geometry were used to verify the simulation. While the simulation forces tended to be high, the trends were still well captured by the simulation model. The thickness and in-plane strains were found to be in good agreement with the experiments.

Car Seat Backrest Static Strength Experiment and Simulation

2009 ◽  
Vol 16-19 ◽  
pp. 178-182 ◽  
Author(s):  
Zhi Wei Xu ◽  
Zhong Qi Sheng ◽  
Hong Hong Zhang ◽  
Yong Xian Liu
Keyword(s):  
Finite Element ◽  
Simulation Analysis ◽  
Model Simulation ◽  
Static Strength ◽  
Analysis Model ◽  
Element Analysis ◽  
Shell Elements ◽  
Car Seat ◽  
Model And Simulation ◽  
The Cost

According to the characteristics of car seat structure and the distribution of car seat load, the finite element static strength model of the car seat is constructed in this paper. The model contains shell elements and beam elements. Some seat structure elements such as welding connection, screw connection, pin connection are simplified in the model. Simulation analysis of the static characteristics of car seat backrest frame model is carried out. At the same time, the experimental research on the static strength characteristics of the back seat is made by the measurements of non-electric physical quantities. By comparing and analyzing the results of experiment and computer simulation of seat static strength, the practicability and credibility of the seat static finite element analysis model and simplified model constructed in this paper are verified. It also proves that the simulation of various connecting forms of the seat structure is effective and is a reliable method in the structural design of the car seat. The model and simulation of the car seat can reduce the cost and shorten the design period.

Study on Key Factors of Numerical Simulation on Automotive Panel Forming

2012 ◽  
Vol 503-504 ◽  
pp. 115-118
Author(s):  
Qiang Wang
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Adaptive Mesh ◽  
Material Model ◽  
Element Formulation ◽  
Key Factors ◽  
Shell Elements ◽  
Automobile Panel ◽  
Hourglass Control ◽  
Element Type

In this paper, for improving simulative accuracy of auto panel forming, some key factors of numerical simulation with finite element method on automobile panel stamping forming are researched. These key factors include finite element algorithm, adaptive mesh, element type and element formulation, hourglass control, material model, and so on. Through simulation example and analysis show that the dynamic explicit algorithm is suitable for metal stamping forming and the static implicit algorithm for springback stage, the adaptive mesh must be adopted in sheet blank forming, element should be selected shell elements, material model should be selected Barlat’s 3-parameter plasticity model.

Discussion on two methods for determining static strength of tubular T-joints at elevated temperature

2016 ◽  
Vol 20 (5) ◽  
pp. 704-721 ◽  
Author(s):  
Yongbo Shao ◽  
Haicheng Zhao ◽  
Dongping Yang
Keyword(s):  
Heat Transfer ◽  
Finite Element ◽  
Elevated Temperature ◽  
Critical Temperature ◽  
Mechanical Analysis ◽  
Static Strength ◽  
T Joints ◽  
Hollow Section ◽  
Tubular Joint ◽  
Circular Hollow Section

To predict the static strength of a welded tubular joint at elevated temperature using finite element simulation, two methods in the literature were reported. The first method aims to analyze the static strength of a tubular joint at a specified elevated temperature, and a routine mechanical analysis is carried out by defining the material properties at the specified elevated temperature according to some specifications. This method does not consider the heat transfer process of the tubular joint in a fire condition. The second method is used to determine the static strength of a tubular joint using a combination of transient state heat transfer analysis and mechanical analysis. The tubular joint subjected to a specified load is heated in accordance with ISO 834-1 standard fire curve to fail at a critical temperature, and the specified load is considered as the static strength of the joint at the critical temperature. In this study, a detailed parametric study on the failure process of circular hollow section tubular T-joints at elevated temperature is carried out using finite element method. The static strengths of the circular hollow section T-joint models obtained from the two methods are compared. The comparison shows that the first method produces a higher estimation on the static strength compared to the second method. Finally, the effect of some geometrical parameters, chord stress ratio, and elevated temperature on the difference of the two methods is also investigated.

Finite Element Modeling of Bolted Cold-Formed Steel Storage Rack Upright Frames

2016 ◽  
Vol 846 ◽  
pp. 251-257
Author(s):  
Nima Talebian ◽  
Benoit P. Gilbert ◽  
Nadia Baldassino ◽  
Hong Guan
Keyword(s):  
Finite Element ◽  
Experimental Test ◽  
Transverse Shear ◽  
Shear Stiffness ◽  
Fe Model ◽  
Test Results ◽  
Shell Elements ◽  
Building Enclosure ◽  
Earthquake Design ◽  
Cold Formed Steel

Steel storage racks, commonly assembled from cold-formed steel profiles, are braced in the cross-aisle direction, where bracing members are typically bolted between two uprights forming an “upright frame”. Especially for high-bay racks and racks supporting the building enclosure, accurately determining the transverse shear stiffness of upright frames is essential in calculating the elastic buckling load, performing earthquake design and serviceability checks. International racking specifications recommend different approaches to evaluate the said transverse shear stiffness. The Rack Manufacturers Institute (RMI) Specification conservatively uses an analytical solution based on Timoshenko and Gere's theory while the European (EN15512) and Australian (AS4084) Specifications recommend testing to be conducted. Previous studies have shown that Finite Element Analyses (FEA), solely using beam elements, fail to reproduce experimental test results and may overestimate the transverse shear stiffness by a factor up to 25. This discrepancy is likely attributed to the local deformations occurring at the bolted joints. In this paper, a commercially used upright frame configuration has been modeled using shell elements in FEA and the response is verified against published experimental test results. A good correlation is found between the FEA and test results, concluding that shell elements are able to fully capture the behaviour of the upright frame. Future studies on the use of the FE model are also presented.

Comparison of Different Radial Basis Functions in Developing Subject-Specific Infant Head Finite Element Models for Injury Biomechanics Study

2012 ◽  
Author(s):  
Zhigang Li ◽  
Jingwen Hu ◽  
Jinhuan Zhang
Keyword(s):  
Finite Element ◽  
Interpolation Method ◽  
Fe Model ◽  
Mesh Quality ◽  
Injury Biomechanics ◽  
Shell Elements ◽  
Mesh Morphing ◽  
Subject Specific ◽  
Radial Basis ◽  
Spatial Interpolation Method

Developing a subject-specific finite element (FE) model, especially with only high quality hexahedral solid elements and quadrilateral shell elements, is very time-consuming. Recently, template-based mesh morphing method has become popular to construct subject-specific FE models, in which a baseline FE mesh can be morphed into a FE model with subject-specific geometry. Because the mesh morphing algorithm could be programmed and run automatically, it is a very promising method for future applications of subject-specific FE models in injury biomechanics studies. Radial Basis Function (RBF) as a powerful spatial interpolation method has already been used as a mesh morphing method (1). The types of RBFs can affect the morphed mesh quality and geometry accuracy in the RBF method. However, to date, no previous study has tried to compare the differences generated by different RBFs. Therefore, in this study, different RBFs were used to morph a baseline infant head FE model into 10 different subject-specific infant head FE models based on CT images from 10 children aged from 0 to 3 months. The mesh quality and geometry accuracy of the subject-specific models generated by different RBFs were compared using statistic analysis.

Development and Validation of a 2D/3D Finite Element Model of a Composite Hemipelvis

2010 ◽  
Author(s):  
Egleide Y. Elenes ◽  
Esra Roan ◽  
Ruxandra C. Marinescu ◽  
Haden A. Janda
Keyword(s):  
Finite Element ◽  
Strain Gauge ◽  
Element Model ◽  
Cortical Layer ◽  
Fourth Generation ◽  
Strain Gauges ◽  
Fe Model ◽  
Shell Elements ◽  
Testing Procedures ◽  
Composite Bone

The use of mechanical analogue composite bone models for a range of biomechanical analyses and testing procedures has grown rapidly since their introduction by Sawbones (Pacific Research Laboratories, Inc., Vashon, WA). The advantages of these composite bones over cadaveric human bones include less variability among specimens, ready availability, lower costs and ease of handling. The fourth generation of Sawbones is now commercially available, which include human femurs, tibiae, humeri and hemipelves. A number of these composite bone models have been mechanically evaluated, i.e. the femur and tibia models, but others such as the hemipelvis have been neglected. However, the composite hemipelvis has been used in several biomechanical research studies; therefore, mechanical validation of the hemipelvis is required. For this study, a robust finite element (FE) model was constructed to investigate the mechanical behavior of a composite left hemipelvis bone model. A computer tomography (CT) scan of the analogue was obtained to produce a computer aided volumetric model. This model was imported and discretized in ABAQUS (Simulia, Providence, RI). In order to reduce computational costs, two-dimensional (2D) shell elements were used to mesh the thin cortical bone layer, while the cancellous bone region was meshed with solid, three-dimensional (3D) tetrahedral elements. A series of FE tests were performed on various shell-solid element domains, to ensure the use of 2D shell elements to model the cortical layer. Once the shell-solid approach was confirmed, a FE model of the hemipelvis was constructed and validated against strain gauge data from quasi-static loading experiments. Three rosette strain gauges (Vishay Micro-Measurements, Raleigh, NC) were mounted on regions of interest along the pubic body, inferior ramus and ischium of the composite hemipelvis. The hemipelvis was fully restrained in a custom-built fixture while quasi-statically loaded using an MTS Mini Bionix II to control the application of 600 N (MTS Systems Corp, Eden Prairie, MN). Maximum and minimum principal strains were calculated from the strain gauge readings and compared to FE predictions of strain at the mounting location of the strain gauges.

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