• Steel and Composite Structures
• /
• v.22 no.4
• /
• pp.753-775
• /
• 2016

This paper aims to investigate the demountability of steel column-baseplate connections subjected to monotonic and cyclic loading. This paper presents the finite element analysis of steel column-baseplate connections under monotonic and cyclic loading. The finite element model takes into account the effects of material and geometric nonlinearities. Bauschinger and pinching effects were also included in the developed model, through which degradation of steel yield strength in cyclic loading can be well simulated. The results obtained from the finite element model are compared with the existing experimental results. It is demonstrated that the finite element model accurately predicts the initial stiffness, ultimate bending moment strength of steel column-baseplate connections. The finite element model is utilised to examine the effects of axial load, baseplate thickness, anchor bolt diameter and position on the behaviour of steel column-baseplate connections. The effects of various parameters on the demountability of steel column-baseplate connections are investigated. To achieve a demountable and reusable structure, various design parameters need to be considered. Initial stiffness and moment capacity of steel columnbaseplate connections are compared with design strengths from Eurocode 3. The comparison between finite element analysis and Eurocode 3 indicates that predictions of initial stiffness for semi-rigid connections should be developed and improved design of the connections needs to be used in engineering practice.

• Structural Engineering and Mechanics
• /
• v.80 no.5
• /
• pp.553-562
• /
• 2021

In this paper, a hybrid scaled boundary finite element and finite volume method (SBFEM-FVM) is proposed for simulating hydraulic-fracture propagation in brittle concrete materials. As a semi-analytical method, the scaled boundary finite element method is introduced for modelling concrete crack propagation under both an external force and water pressure. The finite volume method is employed to model the water within the crack and consider the relationship between the water pressure and the crack opening distance. The cohesive crack model is used to analyse the non-linear fracture process zone. The numerical results are compared with experimental data, indicating that the F-CMOD curves and water pressure changes under different loading conditions are approximately the same. Different types of water pressure distributions are also studied with the proposed coupled model, and the results show that the internal water pressure distribution has an important influence on crack propagation.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2002.05a
• /
• pp.103-107
• /
• 2002

The 2nd forming process of flanging/hemming has recently many interest because it determines external quality of automobile. It is difficult to apply finite element simulation in flanging/hemming due to small element size which needs for expression of bending effect on the die corner and big model size of side door, back door, tank lid and like opening Parts. This paper shows the process of flanging/hemming simulation using finite element model for automotive panels. The explicit finite element program PAM-STAMP$\^$TM/ was used to simulate the flanging and hemming operations.

• Advances in nano research
• /
• v.15 no.2
• /
• pp.141-153
• /
• 2023

The main objective of this paper is to develop the finite element study on the nonlinear free vibration of functionally graded nanocomposite spherical shells reinforced with graphene platelets under the first-order shear deformation shell theory and von Kármán nonlinear kinematic relations. The governing equations are presented by introducing the full asymmetric nonlinear strain-displacement relations followed by the constitutive relations and energy functional. The extended Halpin-Tsai model is utilized to specify the overall Young's modulus of the nanocomposite. Then, the finite element formulation is derived and the quadrilateral 8-node shell element is implemented for finite element discretization. The nonlinear sets of dynamic equations are solved by the use of the harmonic balance technique and iterative method to find the nonlinear frequency response. Several numerical examples are represented to highlight the impact of involved factors on the large-amplitude vibration responses of nanocomposite spherical shells. One of the main findings is that for some geometrical and material parameters, the fundamental vibrational mode shape is asymmetric and the axisymmetric formulation cannot be appropriately employed to model the nonlinear dynamic behavior of nanocomposite spherical shells.

• Tribology and Lubricants
• /
• v.39 no.3
• /
• pp.118-122
• /
• 2023

In our study, we develop a finite element model based on Archard's wear law to predict the cumulative wear and the evolution of the tool profile in friction stir welding (FSW) applications. Our model considers the rotational and translational behaviors of the tool, providing a comprehensive description of the wear process. We validate the accuracy of our model by comparing it against experimental results, examining both the predicted cumulative wear and the resulting changes to the tool profile caused by wear. We perform a detailed comparison between the predictions of the model and experimental data by manipulating non-dimensional coefficients comprising model parameters, such as element sizes and time increments. This comparison facilitates the identification of a specific non-dimensional coefficient condition that best replicates the experimentally observed cumulative wear. We also directly compare the worn tool profiles predicted by the model using this specific non-dimensional coefficient condition with the profiles obtained from wear experiments. Through this process, we identify the model settings that yield a tool wear profile closely aligning with the experimental results. Our research demonstrates that carefully selecting non-dimensional coefficients can significantly enhance the predictive accuracy of finite element models for tool wear in FSW processes. The results from our study hold potential implications for enhancing tool longevity and welding quality in industrial applications.

• Steel and Composite Structures
• /
• v.6 no.4
• /
• pp.285-302
• /
• 2006

This paper describes the design and behaviour of cold-formed stainless steel slender circular hollow section columns. The columns were compressed between fixed ends at different column lengths. The investigation focused on large diameter-to-plate thickness (D/t) ratio ranged from 100 to 200. An accurate finite element model has been developed. The initial local and overall geometric imperfections have been included in the finite element model. The material nonlinearity of the cold-formed stainless steel sections was incorporated in the model. The column strengths, load-shortening curves as well as failure modes were predicted using the finite element model. The nonlinear finite element model was verified against test results. An extensive parametric study was carried out to study the effects of cross-section geometries on the strength and behaviour of stainless steel slender circular hollow section columns with large D/t ratio. The column strengths predicted from the parametric study were compared with the design strengths calculated using the American Specification, Australian/New Zealand Standard and European Code for cold-formed stainless steel structures. It is shown that the design strengths obtained using the Australian/New Zealand and European specifications are generally unconservative for the cold-formed stainless steel slender circular hollow section columns, while the American Specification is generally quite conservative. Therefore, design equation was proposed in this study.

• Journal of the Korean Society of Industry Convergence
• /
• v.20 no.2
• /
• pp.195-204
• /
• 2017

Predicting the failure life of automated manufacturing systems can reduce overall downtime, maintenance costs, and total plant operation costs. Therefore, there is a growing interest in fatigue failure mechanisms as the safety or service life assessment of manufacturing systems becomes an important issue. In particular, fretting fatigue is caused by repeated tangential stresses that are generated by friction during small amplitude oscillatory movements or sliding between two surfaces pressed together in intimate contact. Previous studies in fretting fatigue have observed size effects related to contact width such that a critical contact width exists where there is drastic change in the fretting fatigue life. However, most of them are the two-dimensional finite element analyses based on the plane strain assumption. The purpose of this study is to investigate the contact size effects on the three-dimensional finite element model of a finite width of a flat specimen and a cylindrical pad exposed to fretting fatigue. The contact size effects were analyzed by means of the stress and strain averages at the element integration points of three-dimensional finite element model. This study shows that the fretting fatigue life of manufacturing systems can be predicted by three-dimensional finite element analysis based on SWT critical plane model.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.26 no.8
• /
• pp.1577-1584
• /
• 2002

This paper develops a finite element model for studying the occupant behavior and injury cofficients of a large-sized cab-over type truck. Since it does not have a room to absorb collision energy and deformation in front of the passenger compartment the deformation is directly transmitted to the passenger compartment. Moreover, since its steering column is attached on the frame, severe deformation of the frame directly affects on the steering wheel's movement. Therefore, if the occupant behavior and injury coefficients analysis is performed using a finite element model developed based on a sled test, it is very difficult to expect acquiring satisfactory results. Thus, the finite element model developing in this paper is based on the frontal crash test in order to overcome the inherent problems of the sled test based model commonly used in the passenger car. The occupant behavior and injury coefficients analysis is performed using PAM-CRASH installed in super-computer SP2. In order to validate the reliability of the developed finite element model, a frontal crash test is carried out according to a test method used fur developing truck occupant's secondary safety system in european community and japan. That is, test vehicle's collision direction is vertical to the rigid barrier and collision velocity is 45kph. Thus, measured vehicle pulses at the lower parts of the left and right B-pilla., dummy chest and head deceleration profiles, HIC(head injury criterial) and CA(chest acceleration) values, and dummy behavior from the frontal crash test are compared to the analysis results to validate reliability of the developed model.

• Journal of the Korean Geotechnical Society
• /
• v.16 no.4
• /
• pp.183-190
• /
• 2000

In this research, the finite element analysis of piezocone penetration and dissipation tests have been conducted using the anisotropic elastoplastic-viscoplastic bounding surface model in the Updated Lagrangian reference frame for the large deformation and finite strain nu\ature of piezocone penetration. Accordingly, virtual work equation and corresponding finite element equations have been reformulated. Theory of mixtures has been incorporated to explain the behavior of the sol. It has been observed that the viscoplastic part of the soil model affected the whole formulation. The results of the finite element analysis have been compared and investigated with the experimental results. The formulations and the results are described in part 'I' and part 'II', respectively.

• Journal of Welding and Joining
• /
• v.18 no.4
• /
• pp.28-37
• /
• 2000

In this paper the LNG vessel of the Moss type which is capable of lifting 15,261 tons is investigated in the view point of the pressure vessel preliminary design using the finite element method. The Pressure vessel design is based on the equivalent stress levels due to the internal pressure. The finite element model of the spherical pressure vessel is configured using 4 noded quadrilateral shell element. The finite element analysis program NASTRAN and ANSYS 5.5are implemented. The design is compared with the three kinds of the boundary condition : first, where the equator of the pressure vessel is fixed, and where the top and is fixed, and, the bottom end is fixed, respectively. A comparison is presented between the results obtained by the finite element model and by the prototype production model. Additionally just below position(case 1 & case 2) of equator ring was carried out by using ANSYS 5.5. The results show that the vessel design based on the stress is acceptable at the preliminary design.