Finite Element Modelling to Predict Equivalent Stiffness of 3D Space Frame Structural Joint Using Circular Beam Element

2013 ◽  
Vol 431 ◽  
pp. 104-109 ◽  
Author(s):  
Mohd Shukri Yob ◽  
Shuhaimi Mansor ◽  
Razali Sulaiman
Keyword(s):  
Finite Element ◽  
Research Work ◽  
Experimental Result ◽  
Equivalent Stiffness ◽  
Space Frame ◽  
3D Space ◽  
Vehicle Structure ◽  
Structural Joint ◽  
Circular Beam ◽  
Thin Walled

In automotive industry, thin walled beam is widely used to build vehicles structure. Vehicle structure is built by joining thin walled beams using various welding techniques. The usage of thin walled structure in automotive is important to improve vehicle performance by offering better strength-to-weight ratio. However the application of thin walled structure will cause few drawbacks to vehicle structure. When thin walled beam or structure is loaded with compression load, at certain limit it will undergo local or global buckling. Another problem is when thin walled beam is joined to other thin walled beams, it will show unexpected deformation which called joint flexibility. Both phenomena will cause numerical and analytical model to predict stiffness of structure tend to deviate from experimental result. In vehicle structure fabrication 3D space frame is used a lot. As a case study for this application, area around car bulkhead where cross member, side sill and A pillar are connected to each other at right angle is studied. The intention of this research work is to produce validated finite element model to predict equivalent stiffness of 3D space frame structural joint. Finite element, shell element is most common technique used to model the joined structure. However it is known that shell model cannot produce good result. In this result work, modelling of equivalent stiffness for 3D space frame structural joint is presented. The result shows, using this model the accuracy is about 65%. New modelling technique is proposed to increase the accuracy based on solid model. By introducing circular beam elements at welding area, it is found that accuracy improves up to 90%.

Joint Stiffness of 3D Space Frame Thin Walled Structural Joint Considering Local Buckling Effect

2014 ◽  
Vol 660 ◽  
pp. 773-777
Author(s):  
Mohd Shukri Yob ◽  
Shuhaimi Mansor ◽  
Razali Sulaiman
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Joint Stiffness ◽  
Element Model ◽  
Joint Effect ◽  
Experimental Result ◽  
Space Frame ◽  
3D Space ◽  
Structural Joint ◽  
Thin Walled

Thin walled structure is widely used in designing light weight vehicle. For automotive industry, weight is an important characteristic to increase performance of a vehicle. Vehicle structures are built from thin walled beams by joining them using various joining methods and techniques. For a structure, its stiffness greatly depends on joint stiffness. However, stiffness of thin walled beam is difficult to predict accurately due to buckling effect. Once the beams are joined to form a structure, it will expose to joint flexibility effect. A lot of researches had been done to predict the behaviors of thin walled joint analytically and numerically. However, these methods failed to come out with satisfactory result. In this research work, finite element model for 3D space frame thin walled structural joint is developed using circular beam element by validating with experimental result. Another finite element model using rigid element is used to represent 3D space frame behavior without joint effect. The difference between these 2 models is due to joint effect. By using same modelling technique, joint stiffness for different sizes can be established. Then, the relation between joint stiffness for 3D space frame and size of beam can be obtained.

Individual Stiffness of 3D Space Frame Thin Walled Structural Joint Considering Local Buckling Effect

2014 ◽  
Vol 554 ◽  
pp. 411-415 ◽  
Author(s):  
Mohd Shukri Yob ◽  
Shuhaimi Mansor ◽  
Razali Sulaiman
Keyword(s):  
Research Work ◽  
Local Buckling ◽  
Weight Ratio ◽  
Space Frame ◽  
Thin Walled Structures ◽  
3D Space ◽  
Vehicle Structure ◽  
Cross Member ◽  
Thin Walled ◽  
The Individual

Thin walled beams are widely used to build vehicle structure. Thin walled structure offers high stiffness-to-weight ratio to the vehicle for better handling and fuel consumption. Despite these advantages, thin walled structures will expose to the buckling and joint flexibility effects. For a vehicle structure, 3D space frame is used a lot in designing vehicle structure. However, the stiffness of thin joint is difficult to predict accurately by numerical and analytical model due to buckling effect and the complexity of the joint. The essence of this research work is to determine individual stiffness of 3D space frame members using reduction member method. By knowing the individual stiffness of all members, the stiffness of 3D space frame can be predicted easily. This study will help design engineer to optimize vehicle structure with more efficient way rather than trial and error approach. As a case study, structure around bulkhead area which consists of A pillar, sidesill and cross member will be analyzed.

Plastic Crushing Behavior of Thin-Walled Spheres

2008 ◽  
Vol 33-37 ◽  
pp. 719-724
Author(s):  
P. Xue ◽  
J.P. He ◽  
Yu Long Li
Keyword(s):  
Numerical Simulation ◽  
Finite Element Method ◽  
Plastic Deformation ◽  
Finite Element ◽  
Deformation Process ◽  
Experimental Result ◽  
Plastic Deformation Process ◽  
Post Buckling ◽  
Thin Walled ◽  
Crushing Behavior

Plastic crushing behavior of thin-walled spheres under various loading cases is studied using Finite Element Method. The entire plastic deformation process is tracked during the post-buckling process. The results are compared with the experimental results reported in literature [13], and very good agreements between the numerical simulation and the experimental result are achieved.

Anti-Crashing Energy-Absorbing Simulation and Optimization of Thin-Walled Components

2011 ◽  
Vol 201-203 ◽  
pp. 347-355
Author(s):  
Bing Zhi Chen ◽  
Zhi Dong Lv ◽  
Su Ming Xie ◽  
Wen Zhong Zhao
Keyword(s):  
Finite Element ◽  
Cross Sections ◽  
Experimental Result ◽  
Loading Capacity ◽  
Simulation And Optimization ◽  
Finite Element Software ◽  
Different Shapes ◽  
Thin Walled ◽  
Energy Absorbing ◽  
Different Thickness

Higher speed and loading capacity of trains nowadays have aroused higher ability of crashworthiness, which could be effectively improved by well-designed energy absorbing structures. The thin-walled components, the most traditional and effective energy absorbing device, have been widely used for design of energy absorbing device. As a result, the thin-walled components are used as an example to examine the process of axial compression of it. A comparison of a dynamic compressing simulation on fold-collapse tube and the experimental result of it is made, which shows the two matches very well. Based on this comparison, a further research and optimization on the thin-walled energy absorbing components is implemented. With the material modal and finite element modal of this component, a research on the simulation of PAM-CRASH, the crashing finite element Software, is implemented on such component with different shapes of cross-section, different thickness and square cross-sections with single-cell and multi-cell. What's more, suggestions on such thin-walled components energy absorbing structure is given based on the analysis of the parameters of the simulation.

Post-buckling inelastic analysis of thin-walled metal members using the Generalised Beam Theory

2019 ◽  
Author(s):  
Miguel Abambres ◽  
Dinar Camotim ◽  
Miguel Abambres
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Beam Theory ◽  
Flow Theory ◽  
Promising Alternative ◽  
Inelastic Analysis ◽  
Post Buckling ◽  
Thin Walled ◽  
Shell Finite Element ◽  
Generalised Beam Theory

A 2nd order inelastic Generalised Beam Theory (GBT) formulation based on the J2 flow theory is proposed, being a promising alternative to the shell finite element method. Its application is illustrated for an I-section beam and a lipped-C column. GBT results were validated against ABAQUS, namely concerning equilibrium paths, deformed configurations, and displacement profiles. It was concluded that the GBT modal nature allows (i) precise results with only 22% of the number of dof required in ABAQUS, as well as (ii) the understanding (by means of modal participation diagrams) of the behavioral mechanics in any elastoplastic stage of member deformation .

First and Second Order Elastoplastic Analyses of Thin-Walled Metal Members using Generalized Beam Theory

2018 ◽  
Author(s):  
Miguel Abambres
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Cross Section ◽  
Beam Theory ◽  
Second Order ◽  
Flow Rule ◽  
Non Linear ◽  
Thin Walled ◽  
Shell Finite Element ◽  
Generalized Beam Theory

Original Generalized Beam Theory (GBT) formulations for elastoplastic first and second order (postbuckling) analyses of thin-walled members are proposed, based on the J2 theory with associated flow rule, and valid for (i) arbitrary residual stress and geometric imperfection distributions, (ii) non-linear isotropic materials (e.g., carbon/stainless steel), and (iii) arbitrary deformation patterns (e.g., global, local, distortional, shear). The cross-section analysis is based on the formulation by Silva (2013), but adopts five types of nodal degrees of freedom (d.o.f.) – one of them (warping rotation) is an innovation of present work and allows the use of cubic polynomials (instead of linear functions) to approximate the warping profiles in each sub-plate. The formulations are validated by presenting various illustrative examples involving beams and columns characterized by several cross-section types (open, closed, (un) branched), materials (bi-linear or non-linear – e.g., stainless steel) and boundary conditions. The GBT results (equilibrium paths, stress/displacement distributions and collapse mechanisms) are validated by comparison with those obtained from shell finite element analyses. It is observed that the results are globally very similar with only 9% and 21% (1st and 2nd order) of the d.o.f. numbers required by the shell finite element models. Moreover, the GBT unique modal nature is highlighted by means of modal participation diagrams and amplitude functions, as well as analyses based on different deformation mode sets, providing an in-depth insight on the member behavioural mechanics in both elastic and inelastic regimes.

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